Communication Satellites were first used as the sole means for intercontinental telephony. It was the first and only way that telephone calls could be placed between countries separated by the vast oceans. The introduction of fiber-optic technology in underwater submarine cables allowed an alternate means for intercontinental telephony, so there was a reduction in use […]
Communication Satellites were first used as the sole means for intercontinental telephony. It was the first and only way that telephone calls could be placed between countries separated by the vast oceans. The introduction of fiber-optic technology in underwater submarine cables allowed an alternate means for intercontinental telephony, so there was a reduction in use of communication satellites.
Communication satellites remain important today because of the large number of users and locations that are still not accessible by submarine cables. Remote islands would be one example of a place where it would not be economically feasible to run cables. Additionally, there are countries that are accessed by submarine cables, but the land line system in that country is not adequate to relay the calls to other places in that country. Ships at sea, military combatants in the field, and airplanes are also places where satellite communications remain the only way to communicate. Even places that do have access to submarine cables often have back-up systems that use satellite communications. So, satellite communications remain an important way to stay in contact, and that will remain the case in the future.
ATI is offering a course Satellite Communication Systems which should be of interest to engineers that work in this exciting area. This three-day course covers all the technology of advanced satellite communications, as well as the principles behind current state-of-the-art satellite communications equipment. New and promising technologies will be covered to develop an understanding of the major approaches, including network topologies, VSAT and IP networking over satellite.
The Satellite Communication Systems course begins in early December, so don’t waste any time registering for this ATI short course. You can learn more about the course, and register to attend, here.
As always, you can learn about the many other courses offered by ATI at www.aticourses.com .
Just imagine the communication that occurs between a satellite orbiting the earth and the receiving station on earth. Clearly, in order for that communication to be successful, the signal needs to be received at the earth station with enough SNR (signal to noise ratio) for the signal to be intelligently received and acted upon at […]
Just imagine the communication that occurs between a satellite orbiting the earth and the receiving station on earth.
Clearly, in order for that communication to be successful, the signal needs to be received at the earth station with enough SNR (signal to noise ratio) for the signal to be intelligently received and acted upon at the earth station.
In order for the Satellite designers and the Earth Station designers to do their jobs, they must work together to ensure that transmitting satellite transmits with enough power for the receiving station/dish to understand the signal. This would be simple if we could assume that the receiving dish receives all of the power that the satellite transmits, but that would not be a good assumption. There are various things encountered by the signal during its trip between the satellite and the receiving station which each reduce the power of the signal by a small amount. The transmitter must know how much its transmission will be reduced by all of those things, and account for those losses by boosting transmitting power by that amount so that a reduced received power will still be sufficient for the receiving station to get sufficient SNR in the signal.
A Satellite Link Budget is an accounting of all of the gains and looses that signal will experience in space between a transmitter and a receiver.
So, what are the things that may increase or decrease the power of a signal during its journey between a transmitter and a receiver?
Rain is one example of something that reduces the power contained in the signal. A designer must assume that it will always be raining during the transmission, or they will end up with a system which is only effective on non-rainy days. This would not be a good design.
The easiest way to account for gains and losses is with a proven computer tool like SatMaster from Arrowe. Rain models from the ITU (International Telecommunications Union) provide a viable methodology for assessing rain attenuation in microwave and millimeter wave bands.
And, what are some of the other things that will reduce transmitted power? These are all great questions, beyond the scope of this blog.
If you design transmitters, or if you design receivers, or if you simply want to learn more about Satellite Link Budgets, consider taking the upcoming ATI course Satellite Link Budget Training on the Personal Computer – GEO and non-GEO, L through Q/V bands. You can learn more about this course and register to attend the course here.
There are currently 5 branches of the Armed Forces, namely, Army, Navy, Marines, Air Force, and the Coast Guard. However, in light of changing needs and priorities, President Trump issued a new directive in February to establish the US Space Force as the sixth military branch, which will be within the Department of the Air […]
There are currently 5 branches of the Armed Forces, namely, Army, Navy, Marines, Air Force, and the Coast Guard. However, in light of changing needs and priorities, President Trump issued a new directive in February to establish the US Space Force as the sixth military branch, which will be within the Department of the Air Force.
The directive states that “ Although United States space systems have historically maintained a technological advantage over those of our potential adversaries, those potential adversaries are now advancing their space capabilities and actively developing ways to deny our use of space in a crisis or conflict. It is imperative that the United States adapt its national security organizations, policies, doctrine, and capabilities to deter aggression and protect our interests.”
The directive provides the following priorities for the Space Force:
(a) Protecting the Nation’s interests in space and the peaceful use of space for all responsible actors, consistent with applicable law, including international law;
(b) Ensuring unfettered use of space for United States national security purposes, the United States economy, and United States persons, partners, and allies;
(c) Deterring aggression and defending the Nation, United States allies, and United States interests from hostile acts in and from space;
(d) Ensuring that needed space capabilities are integrated and available to all United States Combatant Commands;
(e) Projecting military power in, from, and to space in support of our Nation’s interests; and
(f) Developing, maintaining, and improving a community of professionals focused on the national security demands of the space domain.
The directive specifies that Space Force will be lead by a civilian to be known as the Undersecretary of the Air Force for Space, and will be appointed by the President and approved by the Senate. The directive specifies that a senior military officer ( General or Admiral ) will serve as the Chief of Staff of the Space Force, and will serve as a member of the Joint Chiefs of Staff.
Applied Technology Institute looks forward to providing training to the workforce which will be needed to support the US Space Force.
A list of all the Space Related Courses offered by ATI can be found at
If your organization requires Space-Related Training which you do not currently see in our Course Offerings, please give us a call and we will try to accommodate your needs.
In 1905 Albert Einstein employed one of the most powerful brains on planet Earth to puzzle out an elusive concept called “The Special Theory of Relativity”. Ten years later he used those same brain cells to develop his even more powerful “General Theory of Relativity”. Figure 1 highlights his most dramatic proposal for proving – […]
In 1905 Albert Einstein employed one of the most powerful brains on planet Earth to puzzle out an elusive concept called “The Special Theory of Relativity”. Ten years later he used those same brain cells to develop his even more powerful “General Theory of Relativity”.
Figure 1 highlights his most dramatic proposal for proving – or disproving! – his General Theory of Relativity. The test he proposed had to take place during a total eclipse of the sun. For, according to The General Theory of Relativity, light from a more distant star would be bent by about one two-thousandths of a degree when it swept by the edge of the sun.
Four years later (in 1919) the talented British astronomer Arthur Eddington in pursuit of a total eclipse of the sun, ventured to the Crimean Peninsula to perform the test Einstein had proposed based on the idea that “starlight would swerve measurably as it passed through the heavy gravity of the sun, a dimple in the fabric of the universe.”*
A black hole comes into existence when a star converts all of its hydrogen into helium and collapses into a much smaller ball that is so dense nothing can escape from its gravitational pull, not even light.
Figure 1: In 1915, when he finally worked out his General Theory of Relativity, Albert Einstein proposed three clever techniques for testing its validity. Four years later, in 1919 the British astronomer, Arthur Eddington, took advantage of one of those tests during a total eclipse of the sun to demonstrate that, when a light beam passes near a massive celestial body, it is bent by the local gravitational field as predicted by Einstein’s theory. This distinctive bending is similar to the manner a baseball headed toward home plate is bent downward by the gravitational pull of the earth.
The existence of black holes was inadvertently predicted by a mathematical relationship Sir Isaac Newton understood and employed in 1687 in developing many of his most powerful scientific predictions, including the rather weird concept of escape velocity. As Figure 2 indicates, it is called the Vis Viva equation.
Start by solving the Vis Viva equation for the radius Re, then plug in the speed of light, C, as a value for the escape velocity, Ve. The resulting radius Re is the so-called “event horizon”, which equals the radius at which light cannot escape from an extremely dense sphere of mass, M. As the calculation on the right-hand side of Figure 2 indicates, if we could somehow compressed the earth down to a radius of 0.35 inches – while preserving its total mass light waves inside the sphere would be unable to escape and, therefore, could not be seen by an observer. The radius of the event horizon associated with a spherical body of mass, M, is directly proportional to the total mass involved.
Figure 2: The Vis Viva equation was developed and applied repeatedly by Isaac Newton when he was evaluating various gravity-induced phenomena. Properly applied, the Vis Viva equation predicts that sufficiently dense celestial bodies generate such strong gravitational fields that nothing – not even a beam of light – can escape their clutches. Today’s astronomers are discovering numerous examples of this counterintuitive effect. Black holes are one result.
As Figure 3 indicates, an enormous black hole 50 million light years from Earth has been discovered to have a mass equal to 2 billion times the mass of our sun. It is located in the M87 Galaxy in the constellation Virgo.
Figure 3: In 1994 the Hubble Space Telescope discovered a huge black hole approximately 300,000,000,000,000,000,000,000 miles from planet Earth nestled among the stars of the M87 galaxy in the Virgo constellation. Astronomers estimate that it is 2,000,000,ooo times heavier than our son. That black hole’s event horizon has a radius of 3,700,000,000 miles or about 40 astronomical units. One astronomical unit being the distance from the earth to our sun.The graph presented in Figure 4 links the masses of various celestial bodies with their corresponding event horizons. Notice that both the horizontal and the vertical axes range over 20 orders of magnitude! In 1942 the Indian-born American astrophysicist, Subrahmanyan Chandrasekhar, demonstrated from theoretical considerations that the smallest black hole that can result from the collapse of a main-sequence star, must have a mass that is equal to approximately 3 suns with a corresponding event horizon of 5.5 miles. The event horizon of a black hole is the maximum radius from which no light can escape.
The graph presented in Figure 4 links the masses of various celestial bodies with their corresponding event horizons. Notice that both the horizontal and the vertical axes range over 20 orders of magnitude! In 1942 the Indian-born American astrophysicist, Subrahmanyan Chandrasekhar, demonstrated from theoretical considerations that the smallest black hole that can result from the collapse of a main-sequence star, must have a mass that is equal to approximately 3 suns with a corresponding event horizon of 5.5 miles. The event horizon of a black hole is the maximum radius from which no light can escape.
See all the ATI courses on 1 page.
What courses would you like to see scheduled as an open-enrollment or on-site course near your facility?
ATI is planning its schedule of technical training courses and would like your recommendations of courses
that will help your project and/or company.
These courses can also be held on-site at your facility.
The researchers at NORAD*, which is located under Cheyenne Mountain in Colorado Springs, Colorado, are currently tracking 20,000 objects in space as big as a softball or bigger. Most of these orbiting objects are space debris fragments that can pose a collision hazard to other orbiting satellites such as the International Space Station. Tracking these […]
The researchers at NORAD*, which is located under Cheyenne Mountain in Colorado Springs, Colorado, are currently tracking 20,000 objects in space as big as a softball or bigger. Most of these orbiting objects are space debris fragments that can pose a collision hazard to other orbiting satellites such as the International Space Station.
Tracking these fragments of debris is complicated and expensive. Preventing collisions is expensive, too. So, too, is designing and building space vehicles that can withstand high-speed impacts. A cheaper alternative may be to sweep some of the debris out of space to minimize its hazard to other orbit-crossing satellites.
When two orbiting objects collide with one another, the energy exchange can be large and destructive. Two one-pound fragments impacting each other in a solid collision in low-altitude orbits intersecting at a 15-degree incidence angle can create the energy caused by exploding two pounds of TNT!!
One scientific study showed that returning substantial numbers of debris fragments to Earth with a hydrogen-fueled spaceborne tug would cost approximately $3 billion for each percent reduction in the fragment population – which has been increasing by about 12 percent per year, on average.
Fortunately, a powerful, but relatively inexpensive laser on the ground pointing vertically upward can be used to deorbit fragments of space debris traveling around the earth in low-altitude orbits. The radial velocity increment provided by such a ground-based laser causes the object to reenter the earth’s atmosphere as shown in the sketch in the upper left-hand corner of Figure 1.
The total required velocity increment can be added in much smaller increments a little at a time over days or weeks. Drag with the atmosphere was neglected in the case considered in Figure 1, but, in the real world, atmospheric drag would help the object return to Earth.
Radiation pressure created by the assumed 50,000 watt laser beam is equivalent to 40 suns spread over the one square foot cross section of the object. The total photon pressure equals 1/13th of a pound per square foot.
* NORAD = North American Aerospace Defense (Command)
The researchers at NORAD*, which is located under Cheyenne Mountain in Colorado Springs, Colorado, are currently tracking 20,000 objects in space as big as a softball or bigger. Most of these orbiting objects are space debris fragments that can pose a collision hazard to other orbiting satellites such as the International Space Station.
Tracking these fragments of debris is complicated and expensive. Preventing collisions is expensive, too. So, too, is designing and building space vehicles that can withstand high-speed impacts. A cheaper alternative may be to sweep some of the debris out of space to minimize its hazard to other orbit-crossing satellites.
When two orbiting objects collide with one another, the energy exchange can be large and destructive. Two one-pound fragments impacting each other in a solid collision in low-altitude orbits intersecting at a 15-degree incidence angle can create the energy caused by exploding two pounds of TNT!!
One scientific study showed that returning substantial numbers of debris fragments to Earth with a hydrogen-fueled spaceborne tug would cost approximately $3 billion for each percent reduction in the fragment population – which has been increasing by about 12 percent per year, on average.
Fortunately, a powerful, but relatively inexpensive laser on the ground pointing vertically upward can be used to deorbit fragments of space debris traveling around the earth in low-altitude orbits. The radial velocity increment provided by such a ground-based laser causes the object to reenter the earth’s atmosphere as shown in the sketch in the upper left-hand corner of Figure 1.
The total required velocity increment can be added in much smaller increments a little at a time over days or weeks. Drag with the atmosphere was neglected in the case considered in Figure 1, but, in the real world, atmospheric drag would help the object return to Earth.
Radiation pressure created by the assumed 50,000 watt laser beam is equivalent to 40 suns spread over the one square foot cross section of the object. The total photon pressure equals 1/13th of a pound per square foot.
* NORAD = North American Aerospace Defense (Command)
Figure 2: These engineering calculations show that the 20,000 space debris fragments now circling the earth in low-altitude orbits could, on average, each be deorbited with ground-based lasers for approximately $40,000 worth of electrical power. Those same ground-based lasers could be used in a different mode to reboost valuable or dangerous payloads in low-altitude orbits or to send those payloads bound for geosynchoronous orbits onto their transfer ellipses. (SOURCE: Short course “Fundamentals of Space Exploration”. Instructor: Tom Logsdon. (Seal Beach, CA)
See all the ATI courses on 1 page.
What courses would you like to see scheduled as an open-enrollment or on-site course near your facility?
ATI is planning its schedule of technical training courses and would like your recommendations of courses
that will help your project and/or company.
These courses can also be held on-site at your facility.
Tom Logsdon teaches a number of courses for Applied Technology Institute including: Orbital & Launch Mechanics – Fundamentals GPS Technology Strapdown and Integrated Navigation Systems Breakthrough Thinking: Creative Solutions for Professional Success The article below was written by him could be of interest to our readers. AMERICA’S INFRARED SPITZER TELESCOPE “As in the soft and […]
NASA’s Spitzer Space Telescope, which launched Aug. 25, 2003, will begin the “Beyond” phase of its mission on Oct. 1, 2016. Spitzer has been operating beyond the limits that were set for it at the beginning of its mission, and making discoveries in unexpected areas of science, such as exoplanets.
Tom Logsdon teaches a number of courses for Applied Technology Institute including:
The article below was written by him could be of interest to our readers.
AMERICA’S INFRARED SPITZER TELESCOPE“As in the soft and sweet eclipse, when soul meets soul on lover’s lips.”
British Lyric Poet
Percy Shelly
Prometheus Unbound, 1820
America’s famous inventor, Thomas Edison, The Wizard of Menlo Park, had long admired the somber, romantic words penned by England’s master poet Percy Shelly. And, like Shelly, he, too, was enchanted with the sensual experiences conjured up by the periodic eclipses that blotted out the sun and the moon.
In 1878 Edison clambered aboard the newly constructed transcontinental railroad headed from New Jersey to Wyoming where he hoped to utilize his newly constructed infrared sensor to study the total solar eclipse he knew would soon sweep across America’s western landscape. When he arrived in Wyoming, the only building he could rent was an old chicken coop at the edge of the prairie. And, as soon as the moon slipped in front of the sun causing the sky to darken, the chickens decided to come to roost.
Soon The Wizard of Menlo Park was so busy trying to quiet his squawking companions, he caught only a fleeting glimpse of the rare and colorful spectacle lighting up the darkened daytime sky. His infrared sensor, unfortunately, remained untested that day.
Even if those agitated Wyoming chickens had behaved themselves with proper decorum during that unusual event, Thomas Edison’s sensor would have been entirely ineffective because most of the infrared frequencies emanating from the sun and the stars are absorbed by the atmosphere surrounding the earth. However, sensors of similar design can, and do, handle important astronomical tasks when they are installed in cryogenically cooled telescopes launched into space by powerful and well-designed rockets.
The infrared rays streaming down to earth from distant stars and galaxies lie just beyond the bright red colors at the edge of in the electromagnetic spectrum our eyes can see. As such, they penetrate the clouds of dust found, in such abundance, in interstellar space. The dust that has accumulated under your bed is not particularly valuable or interesting. But the dust found in outer space is far more beneficial – and exciting, too!
The Spitzer Space Telescope – a giant thermos bottle in space – now following along behind planet earth as it circles the sun, was an effective infrared telescope until it used up its entire supply of liquid helium coolant. In the meantime, it has become a “warm” space-age telescope seeking out previously undiscovered exoplanets orbiting around suns trillions of miles away. This is accomplished by observing their shadows periodically dimming the star’s visible light as the various planets coast in between the Spitzer and the celestial body being observed.
See all the ATI courses on 1 page.
What courses would you like to see scheduled as an open-enrollment or on-site course near your facility?
ATI is planning its schedule of technical training courses and would like your recommendations of courses
that will help your project and/or company.
These courses can also be held on-site at your facility.
How to Promote Your ATI Course in Social Media LinkedIn for ATI Rocket Scientists Did you know that for 52% of professionals and executives, their LinkedIn profile is the #1 or #2 search result when someone searches on their name? For ATI instructors, that number is substantially lower – just 17%. One reason is […]
How to Promote Your ATI Course in Social MediaLinkedIn for ATI Rocket Scientists
Did you know that for 52% of professionals and executives, their LinkedIn profile is the #1 or #2 search result when someone searches on their name?
For ATI instructors, that number is substantially lower – just 17%. One reason is that about 25% of ATI instructors do not have a LinkedIn profile. Others have done so little with their profile that it isn’t included in the first page of search results.
If you are not using your LinkedIn profile, you are missing a huge opportunity. When people google you, your LinkedIn profile is likely the first place they go to learn about you. You have little control over what other information might be available on the web about you. But you have complete control over your LinkedIn profile. You can use your profile to tell your story – to give people the exact information you want them to have about your expertise and accomplishments.
Why not take advantage of that to promote your company, your services, and your course?
Here are some simple ways to promote your course using LinkedIn…
On Your LinkedIn Profile
Let’s start by talking about how to include your course on your LinkedIn profile so it is visible anytime someone googles you or visits your profile.
1. Add your role as an instructor.
Let people know that this course is one of the ways you share your knowledge. You can include your role as an instructor in several places on your profile:
Experience – This is the equivalent of listing your role as a current job. (You can have more than one current job.) Use Applied Technology Institute as the employer. Make sure you drag and drop this role below your full-time position.
Summary – Your summary is like a cover letter for your profile – use it to give people an overview of who you are and what you do. You can mention the type of training you do, along with the name of your course.
Projects – The Projects section gives you an excellent way to share the course without giving it the same status as a full-time job.
Headline – Your Headline comes directly below your name, at the top of your profile. You could add “ATI Instructor” at the end of your current Headline.
Start with an introduction, such as “I teach an intensive course through the Applied Technology Institute on [course title]” and copy/paste the description from your course materials or the ATI website. You can add a link to the course description on the ATI website.
This example from Tom Logsdon’s profile, shows how you might phrase it:
Here are some other examples of instructors who include information about their courses on their LinkedIn profile:
Buddy Wellborn – His Headline says “Instructor at ATI” and Buddy includes details about the course in his Experience section.
D. Lee Fugal – Mentions the course in his Summary and Experience.
Jim Jenkins – Courses are included throughout Jim’s profile, including his Headline, Summary, Experience, Projects, and Courses.
2. Link to your course page.
In the Contact Info section of your LinkedIn profile, you can link out to three websites. To add your course, go to Edit Profile, then click on Contact Info (just below your number of connections, next to a Rolodex card icon). Click on the pencil icon to the right of Websites to add a new site.
Choose the type of website you are adding. The best option is “Other:” as that allows you to insert your own name for the link. You have 35 characters – you can use a shortened version of your course title or simply “ATI Course.” Then copy/paste the link to the page about your course.
This example from Jim Jenkins’ profile shows how a customized link looks:
3. Upload course materials.
You can upload course materials to help people better understand the content you cover. You could include PowerPoint presentations (from this course or other training), course handouts (PDFs), videos or graphics. They can be added to your Summary, Experience or Project. You can see an example of an upload above, in Tom Logsdon’s profile.
4. Add skills related to your course.
LinkedIn allows you to include up to 50 skills on your profile. If your current list of skills doesn’t include the topics you cover in your course, you might want to add them.
Go to the Skills & Endorsements section on your Edit Profile page, then click on Add skill. Start typing and let LinkedIn auto-complete your topic. If your exact topic isn’t included in the suggestions, you can add it.
5. Ask students for recommendations.
Are you still in touch with former students who were particularly appreciative of the training you provided in your course? You might want to ask them for a recommendation that you can include on your profile. Here are some tips on asking for recommendations from LinkedIn expert Viveka Von Rosen.
6. Use an exciting background graphic.
You can add an image at the top of your profile – perhaps a photo of you teaching the course, a photo of your course materials, a graphic from your presentation, or simply some images related to your topic. You can see an example on Val Traver’s profile.
Go to Edit Profile, then run your mouse over the top of the page (just above your name). You will see the option to Edit Background. Click there and upload your image. The ideal size is 1400 pixels by 425. LinkedIn prefers a JPG, PNG or GIF. Of course, only upload an image that you have permission to use.
Share News about Your Course
You can also use LinkedIn to attract more attendees to your course every time you teach.
7. When a course date is scheduled, share the news as a status update.
This lets your connections know that you are teaching a course – it’s a great way to reach the people who are most likely to be interested and able to make referrals.
Go to your LinkedIn home page, and click on the box under your photo that says “Share an update.” Copy and paste the URL of the page on the ATI website that has the course description. Once the section below populates with the ATI Courses logo and the course description, delete the URL. Replace it with a comment such as:
“Looking forward to teaching my next course on [title] for @Applied Technology Institute on [date] at [location].”
Note that when you finish typing “@Applied Technology Institute” it will give you the option to click on the company name. When you do that ATI will know you are promoting the course, and will be deeply grateful!
When people comment on your update, it’s nice to like their comment or reply with a “Thank you!” message. Their comment shares the update with their network, so they are giving your course publicity.
If you want to start doing more with status updates, here are some good tips about what to share (and what not to share) from LinkedIn expert Kim Garst.
8. Share the news in LinkedIn Groups.
If you have joined any LinkedIn Groups in your areas of expertise, share the news there too.
Of course, in a Group you want to phrase the message a little differently. Instead of “Looking forward to teaching…” you might say “Registration is now open for…” or “For everyone interested in [topic], I’m teaching…”
You could also ask a thought-provoking question on one of the topics you cover. Here are some tips about how to start an interesting discussion in a LinkedIn Group.
9. Post again if you still have seats available.
If the course date is getting close and you are looking for more people to register, you should post again. The text below will work as a status update and in most LinkedIn Groups.
“We still have several seats open for my course on [title] on [date] at [location]. If you know of anyone who might be interested, could you please forward this? Thanks. ”
“We have had a few last-minute cancellations for my course on [title] on [date] at [location]. Know anyone who might be interested in attending?”
10. Blog about the topic of the course.
When you publish blog posts on LinkedIn using their publishing platform, you get even more exposure than with a status update:
The blog posts are pushed out to all your connections.
They stay visible on your LinkedIn profile, and
They are made available to Google and other search engines.
A blog post published on LinkedIn will rank higher than one posted elsewhere, because LinkedIn is such an authority site. So this can give your course considerable exposure.
You probably have written articles or have other content relevant to the course. Pick something that is 750-1500 words.
To publish it, go to your LinkedIn home page, and click on the link that says “Publish a post.” The interface is very simple – easier than using Microsoft Word. Include an image if you can. You probably have something in your training materials that will be perfect.
At the end of the post, add a sentence that says:
“To learn more, attend my course on [title].”
Link the title to the course description on the ATI website.
For more tips about blogging, you are welcome to join ProResource’s online training website. The How to Write Blog Posts for LinkedIn course is free.
Take the first step
The most important version of your bio in the digital world is your LinkedIn summary. If you only make one change as a result of reading this blog post, it should be to add a strong summary to your LinkedIn profile. Write the summary promoting yourself as an expert in your field, not as a job seeker. Here are some resources that can help:
Write the first draft of your profile in a word processing program to spell-check and ensure you are within the required character counts. Then copy/paste it into the appropriate sections of your LinkedIn profile. You will have a stronger profile that tells your story effectively with just an hour or two of work!
Contributed by guest blogger Judy Schramm. Schramm is the CEO of ProResource, a marketing agency that works with thought leaders to help them create a powerful and effective presence in social media. ProResource offers done-for-you services as well as social media executive coaching. Contact Judy Schramm at jschramm@proresource.com or 703-824-8482.
Applied Technology Institute (ATI Courses) offers a variety of courses on spacecraft design. spacecraft quality control or spacecraft thermal design. We think the news below could be of interest to our readers. An international inquiry is under way into an embarrassing error which has left two multi-million European satellites that were launched from French Guiana in […]
The satellites were launched on Friday from French GuianaApplied Technology Institute (ATI Courses)offers a variety of courses on spacecraft design. spacecraft quality control or spacecraft thermal design.
We think the news below could be of interest to our readers.
An international inquiry is under way into an embarrassing error which has left two multi-million European satellites that were launched from French Guiana in the wrong orbit.
On 22 August, a Soyuz rocket launched the fifth and sixth satellites of Europe’s Galileo project, a satellite navigation system that will eventually comprise 30 satellites designed to make Europe independent of U.S., Russian, and other GPS systems. Unlike most Soyuz launches, the rocket did not lift off from Baikonur, Kazakhstan, but from Kourou, Europe’s space center in French Guiana. Apparently the launch went off without incident, but it soon became apparent that the two satellites were injected into the wrong orbits. The upper stage of the Soyuz rocket, the Fregat-MT, injected them into elliptical orbits instead of circular ones, making the satellites unusable for GPS navigation.
The issue was the result of a frozen full pipe that delivered hydrazine to thrusters necessary to align the Fregat upper stage ready for correct orbital injection.
The freeze was the result of cold helium feed lines being installed in close proximity to the hydrazine fuel lines. They were collectedly the same support structure which led to a thermal bridge. This sequence of events occurred due to a design ambiguity which failed to recognize the possibility of thermal transfer between these components.
While it doesn’t help the two satellites that are now effectively lost to the Galileo network, it is at least a simple fix and will not result in delays to the next launch scheduled for December.
The Soyuz TMA-06M spacecraft docked at the space station’s rooftop after a two-day orbital chase. Riding on the Soyuz were American astronaut Kevin Ford of NASA and Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin, who are beginning a five-month mission to the space station. “We can see you, everything looks fine,” Russian cosmonaut Yuri Malenchenko, who was […]
The Soyuz TMA-06M spacecraft docked at the space station’s rooftop after a two-day orbital chase. Riding on the Soyuz were American astronaut Kevin Ford of NASA and Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin, who are beginning a five-month mission to the space station.
“We can see you, everything looks fine,” Russian cosmonaut Yuri Malenchenko, who was already onboard the station, told the approaching crew before the two spacecraft docked about 230 miles (370 km) over southern Ukraine.
Ford, Novitskiy and Tarelkin launched into space on Tuesday (Oct. 23) atop a Soyuz rocket that blasted off from the Central Asian spaceport of Baikonur Cosmodrome in Kazakhstan. They are the second half of the space station’s six-person Expedition 33 crew, which is commanded by NASA astronaut Sunita Williams. Malenchenko and Japanese astronaut Akihiko Hoshide round out the crew.
The Soyuz spacecraft is bringing some fishy friends to the space station in addition to its human crew. The spacecraft is ferrying 32 small medaka fish to the space station so they can be placed inside a tank, called the Aquatic Habitat, for an experiment to study how fish adapt to weightlessness.
Thursday’s Soyuz docking at the space station kicks off a flurry of arrivals and departures at the International Space Station.
A robotic Dragon space capsule built by the private spaceflight company SpaceX will depart the space station on Sunday (Oct. 28) and splash down in the Pacific Ocean off the coast of Southern California. The Dragon capsule will return nearly 2,000 pounds (907 kilograms) of science experiment hardware and other gear back to Earth.
On Wednesday (Oct. 31), an unmanned Russian Progress spacecraft will launch toward the space station and arrive six hours later to make a Halloween delivery of food, equipment and other Halloween treats.
Williams, Hoshide and Malenchenko are in the final weeks of their mission to the space station, and will return to Earth Nov. 12. At that time, Ford will take command of the space station crew to begin the Expedition 34 mission.
Video Clip: Click to Watch Everything about Orbital Mechanics is Counterintuitive Award-winning rocket scientist, Thomas S. Logsdon really enjoys teaching this short course titled, ATI’s Orbital Mechanics: Ideas and Insights, because everything about orbital mechanics is counterintuitive. In this comprehensive four day short course, Mr. Logsdon uses four hundred clever color graphics to clarify these and […]
Each student will receive a new personal GPS Navigator with multi-channel capability
Everything about Orbital Mechanics is Counterintuitive
Award-winning rocket scientist, Thomas S. Logsdon really enjoys teaching this short course titled, ATI’s Orbital Mechanics: Ideas and Insights, because everything about orbital mechanics is counterintuitive.
In this comprehensive four day short course, Mr. Logsdon uses four hundred clever color graphics to clarify these and a dozen other puzzling mysteries associated with orbital mechanics. He also provides you with a few simple one-page derivations using real-world inputs to illustrate all the key concepts being explored.
For example, did you know that if you fly your spacecraft into a 100-mile circular orbit and:
• Put on the brakes, your spacecraft speeds up!
• Mash down the accelerator, it slows down!!
• Throw a banana peel out the window and 45 minutes later it will come back and slap you in the face!!!
Why not take a short course?
Since 1984, the Applied Technology Institute (ATI) has provided leading-edge public courses and onsite technical training to DoD and NASA personnel, as well as contractors. ATI short courses are less than a week long and are designed to help you keep your professional knowledge up-to-date.
Our courses provide a practical overview of space and defense technologies which provide a strong foundation for understanding the issues that must be confronted in the use, regulation and development of complex systems. Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of satellite systems in a short time. You will become aware of the basic vocabulary essential to interact meaningfully with your colleagues.
Determine for yourself the value of our courses before you sign up.
Click here for more information on this courseClick below to see slide samples from this course
Click below to see a video clip of this course on YouTube.
What You Will Learn When You Take this Course:• How do we launch a satellite into orbit and maneuver it into a new location?
• How do today’s designers fashion performance-optimal constellations of satellites swarming the sky?
• How do planetary swing by maneuvers provide such amazing gains in performance?
• How can we design the best multi-stage rocket for a particular mission?
• What are libration point orbits? Were they really discovered in 1772? How do we place satellites into halo orbits circling around these empty points in space?
• What are JPL’s superhighways in space? How were they discovered? How are they revolutionizing the exploration of space?
After attending the course you will receive a full set of detailed notes from the class for future reference, as well as a certificate of completion. Each student will receive a new personal GPS Navigator with multi-channel capability. Please visit our website for more valuable information.
About ATI and the InstructorsOur mission here at ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses. ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.
For more than 30 years, Thomas S. Logsdon, has conducted broad ranging studies on orbital mechanics at McDonnell Douglas, Boeing Aerospace, and Rockwell International His key research projects have included Project Apollo, the Skylab capsule, the nuclear flight stage and the GPS radionavigation system.
Mr. Logsdon has taught 300 short courses and lectured in 31 different countries on six continents. He has written 40 technical papers and journal articles and 29 technical books including Striking It Rich in Space, Orbital Mechanics: Theory and Applications, Understanding the Navstar, and Mobile Communication Satellites.
Dates and LocationsThe next date and location of this short course is:
Jan 9-12, 2012 Cape Canaveral,FL
Video Clip: Click to Watch If not, then maybe you need ATI’s SATCOM Technology and Networks course This three-day short course provides accurate background in the fundamentals, applications and approach for cutting-edge satellite networks for use in military and civil government environments. The focus is on commercial SATCOM solutions (GEO and LEO) and government satellite systems […]
MILSTAR Satellite Communications System
Video Clip: Click to Watch
If not, then maybe you need ATI’s SATCOM Technology and Networks courseThis three-day short course provides accurate background in the fundamentals, applications and approach for cutting-edge satellite networks for use in military and civil government environments. The focus is on commercial SATCOM solutions (GEO and LEO) and government satellite systems (WGS, MUOS and A-EHF), assuring thorough coverage of evolving capabilities. It is appropriate for non-technical professionals, managers and engineers new to the field as well as experienced professionals wishing to update and round out their understanding of current systems and solutions.
ATI’S SATCOM TECHNOLOGY AND NETWORKS COURSEWhat you will learn:
• How a satellite functions to provide communications links to typical earth stations and user terminals
• The various technologies used to meet requirements for bandwidth, service quality and reliability
• Basic characteristics of modulation, coding and Internet Protocol processing
• How satellite links are used to satisfy requirements of the military for mobility and broadband network services for warfighters
• The characteristics of the latest US-owned MILSATCOM systems, including WGS, MUOS, A-EHF, and the approach for using commercial satellites at L, C, X, Ku and Ka bands
• Proper application of SATCOM to IP networks
Course Outline, Samplers, and NotesIn addition to the course notes, each participant will receive a book of collected tutorial articles written by the instructor, and soft copies of the link budgets discussed in the course. Please visit our website for more valuable information.
About ATI and the InstructorsOur mission here at ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses. ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.
Bruce Elbert is a recognized SATCOM technology and network expert and has been involved in the satellite and telecommunications industries for over 35 years. He consults to major satellite organizations and government agencies in the technical and operations aspects of applying satellite technology. Prior to forming his consulting firm, he was Senior Vice President of Operations in the international satellite division of Hughes Electronics (now Boeing Satellite), where he introduced advanced broadband and mobile satellite technologies. He directed the design of several major satellite projects, including Palapa A, Indonesia’s original satellite system; the Hughes Galaxy satellite system; and the development of the first GEO mobile satellite system capable of serving handheld user terminals. He has written seven books on telecommunications and IT.
Times, Dates, and LocationsThis short course can be presented at your facility at your convenience. An onsite presentation is economical when 6-8 people want the course and a great value if you have more than 10 who are interested. I suggest that you read through the course description and then call me personally, Jim Jenkins, at 410-956-8805 or toll free at 1-888-501-2100, and I’ll explain in detail what we can do for you, what it will cost, and what you can expect in results and future capabilities.
Video Clip: Click to Watch ATI presents: An overview of commercial satellite communications hardware, operations, business and regulatory environment This three-day introductory course has been taught to rave reviews to thousands of industry professionals for over two decades. The material is frequently updated and the course is a primer to the concepts, jargon, buzzwords, and acronyms […]
ATI presents:An overview of commercial satellite communications hardware, operations, business and regulatory environment
This three-day introductory course has been taught to rave reviews to thousands of industry professionals for over two decades. The material is frequently updated and the course is a primer to the concepts, jargon, buzzwords, and acronyms of the industry, plus an overview of commercial satellite communications hardware, operations, and business environment.
Here is Dr. Mark R. Chartrand, course instructor, on YouTube.
Since 1984, the Applied Technology Institute (ATI) has provided leading-edge public courses and onsite technical training to DoD and NASA personnel, as well as contractors. Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of complex satellite systems in a short time. You will become aware of the basic vocabulary essential to interact meaningfully with your colleagues.
Here is more about the course.
SATELLITE COMMUNICATIONS COURSE — AN ESSENTIAL INTRODUCTIONThe first section provides non-technical people with the technical background necessary to understand the space and earth segments of the industry, culminating with the importance of the link budget. The concluding section of the course provides an overview of the business issues, including major operators, regulation and legal issues, and issues and trends affecting the industry.
What You Will Learn:• How do commercial satellites fit into the telecommunications industry?
• How are satellites planned, built, launched, and operated?
• How do earth stations function?
• What is a link budget and why is it important?
• What legal and regulatory restrictions affect the industry?
• What are the issues and trends driving the industry?
The course is intended primarily for non-technical people who must understand the entire field of commercial satellite communications, and who must understand and communicate with engineers and other technical personnel. The secondary audience is technical personnel moving into the industry who need a quick and thorough overview of what is going on in the industry.
Concepts are explained at a basic level, minimizing the use of math, and providing real-world examples. Several calculations of important concepts such as link budgets are presented for illustrative purposes, but the details need not be understood in depth to gain an understanding of the concepts illustrated.
Course Outline, Samplers, and NotesOur short courses are designed for individuals involved in planning, designing, building, launching, and operating space and satellite systems.
Don’t believe it?
Here is what one of our recent students had to say about this course.
“I truly enjoyed your course and hearing of your adventures in the Satellite business. You have a definite gift in teaching style and explanations.”
Still not convinced?
You can see for yourself the value of our course before you sign up.
View Satellite Course Sampler
You can also check out some of our other short courses on the ATI YouTube channel.
Attendees receive a copy of the instructor’s new textbook, Satellite Communications for the Non-Specialist, and will have time to discuss issues pertinent to their interests.
After completing the course, you will also receive a certificate of completion. Please visit our website for more valuable information.
About ATI and the InstructorsOur mission here at ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses.
ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.
Dr. Mark R. Chartrand is a consultant and lecturer in satellite telecommunications and the space sciences. For more than 25 years he has presented professional seminars on satellite technology and telecommunications to satisfied individuals and businesses throughout the United States, Canada, Latin America, Europe and Asia.
Dr. Chartrand has served as a technical and/or business consultant to NASA, Arianespace, GTE Spacenet, Intelsat, Antares Satellite Corp., Moffett-Larson-Johnson, Arianespace, Delmarva Power, Hewlett-Packard, and the International Communications Satellite Society of Japan, among others.
He has appeared as an invited expert witness before Congressional subcommittees and was an invited witness before the National Commission on Space.
He was the founding editor and the Editor-in-Chief of the annual The World Satellite Systems Guide, and later the publication Strategic Directions in Satellite Communication. He is author of six books and hundreds of articles in the space sciences. He has been chairman of several international satellite conferences, and a speaker at many others.
Times, Dates, and LocationsThe times, dates and locations of our Satellite Communications – An Essential Introduction short course are as follows:
Sep 20-22, 2011 Cocoa Beach
Nov 29-Dec 1, 2011 Laurel, MD
Apr 17-19, 2012 Columbia, MD
NASA announced that it awarded $269,3 million to the following companies in order to accelerate human spaceflight capability and commercial crew transportation. The companies were selected for the second round of the Commercial Crew Development (CCDev2). Blue Origin is a privately-funded aerospace company set up by Amazon.com founder Jeff Bezos. The company was awarded $3.7 million in funding […]
NASA announced that it awarded $269,3 million to the following companies in order to accelerate human spaceflight capability and commercial crew transportation. The companies were selected for the second round of the Commercial Crew Development (CCDev2).
Blue Originis a privately-funded aerospace company set up by Amazon.com founder Jeff Bezos. The company was awarded $3.7 million in funding in 2009 by NASA via a Space Act Agreement under the Commercial Crew Development (CCDev) program for development of concepts and technologies to support future human spaceflight operations. The company’s innovative ‘pusher’ Launch Abort System (LAS) was one of the technologies that was of particular interest to NASA. To date abort systems have been of the tractor variety, which pulls a crew vehicle to safety in case of an emergency.
Initially focused on sub-orbital spaceflight, the company has built and flown a testbed of its New Shepard spacecraft design at their Culberson County, Texas facility. According to company statements, it initially planned on placing the New Shepard in commercial suborbital tourist service in 2010 with flights about once a week. However, the most recently publicized timetable states that Blue Origin will fly unmanned in 2011, and manned in 2012.
Sierra Nevada Corporation(SNC) is an electronic systems provider and systems integrator specializing in microsatellites, energy, telemedicine, nanotechnology, and commercial orbital transportation services. The company contracts with the US military, NASA and private spaceflight companies. The company is headquartered in Sparks, Nevada.
SNC employs over 2000 people. SNC has six different business areas, and 35 locations in 16 states along with numerous customer support sites located throughout the world.
Space Exploration Technologies Corp. (SpaceX) is an American space transport company founded by PayPal co-founder Elon Musk. It has developed the Falcon 1 and Falcon 9 rockets, both of which are built with a goal of being reusable launch vehicles. SpaceX is also developing the Dragon spacecraft to be carried to orbit by Falcon 9 launch vehicles. SpaceX designs, tests and fabricates the majority of their components in-house, including the Merlin, Kestrel, and Draco rocket engines. In December 2010, SpaceX became the first private company to successfully launch, orbit and recover a spacecraft (a Dragon).
Originally based in El Segundo, SpaceX now operates out of Hawthorne, California, USA.
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois[2] since 2001. Boeing is made up of multiple business units, which are Boeing Commercial Airplanes (BCA); Boeing Defense, Space & Security (BDS); Engineering, Operations & Technology; Boeing Capital; and Boeing Shared Services Group.
Washington, DC Tuesday, November 30, 2010 “Even I Could Learn a Thing or Two from ATI” Video Clip: Click to Watch Since 1984 ATI has provided leading-edge public courses and onsite technical training The short technical courses from the Applied Technology Institute (ATI) are designed to help you keep your professional knowledge up-to-date. Our courses provide […]
Since 1984 ATI has provided leading-edge public courses
and onsite technical training
The short technical courses from the Applied Technology Institute (ATI) are designed to help you keep your professional knowledge up-to-date. Our courses provide a practical overview of space and defense technologies which provide a strong foundation for understanding the issues that must be confronted in the use, regulation and development such complex systems.
The classes are designed for individuals involved in planning, designing, building, launching, and operating space and defense systems. Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of complex systems in a short time.
ABOUT ATI AND THE INSTRUCTORS
Our mission here at the ATI is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses.
ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.
For example:
Robert Fry worked from 1979 to 2007 at The Johns Hopkins University Applied Physics Laboratory where he was a member of the Principal Professional Staff. He is now working at System Engineering Group (SEG) where he is Corporate Senior Staff and also serves as the company-wide technical advisor. Throughout his career he has been involved in the development of new combat weapon system concepts, development of system requirements, and balancing allocations within the fire control loop between sensing and weapon kinematic capabilities. He has worked on many aspects of the AEGIS combat system including AAW, BMD, AN/SPY-1, and multi-mission requirements development. Missile system development experience includes SM-2, SM-3, SM-6, Patriot, THAAD, HARPOON, AMRAAM, TOMAHAWK, and other missile systems.
Robert teaches ATI’s Combat Systems Engineering course
Wayne Tustin has been president of Equipment Reliability Institute (ERI), a specialized engineering school and consultancy he founded in Santa Barbara, CA, since 1995. His BSEE degree is from the University of Washington, Seattle. He is a licensed Professional Engineer in the State of California. Wayne’s first encounter with vibration was at Boeing/Seattle, performing what later came to be called modal tests, on the XB-52 prototype of that highly reliable platform. Subsequently he headed field service and technical training for a manufacturer of electrodynamic shakers, before establishing another specialized school on which he left his name.
Based on over 50 years of professional experience, Wayne has written several books and literally hundreds of articles dealing with practical aspects of vibration and shock measurement and testing.
Wayne teaches ATI’s Fundamentals of Random Vibration & Shock Testing course.
Thomas S. Logsdon, M.S
For more than 30 years, Thomas S. Logsdon, M. S., has worked on the Navstar GPS and other related technologies at the Naval Ordinance Laboratory, McDonnell Douglas, Lockheed Martin, Boeing Aerospace, and Rockwell International. His research projects and consulting assignments have included the Transit Navigation Satellites, The Tartar and Talos shipboard missiles, and the Navstar GPS. In addition, he has helped put astronauts on the moon and guide their colleagues on rendezvous missions headed toward the Skylab capsule. Some of his more challenging assignments have centered around constellation coverage studies, GPS performance enhancement, military applications, spacecraft survivability, differential navigation, booster rocket guidance using the GPS signals and shipboard attitude determination.
Tom Logsdon has taught short courses and lectured in thirty one different countries. He has written and published forty technical papers and journal articles, a dozen of which have dealt with military and civilian radionavigation techniques. He is also the author of twenty nine technical books on various engineering and scientific subjects. These include Understanding the Navstar, Orbital Mechanics: Theory and Applications, Mobile Communication Satellites, and The Navstar Global Positioning System.
Courses Mr. Logsdon teaches through ATI include:
Understanding SpaceFundamentals of Orbital & Launch MechanicsGPS Technology – Solutions for Earth & Space and
Strapdown Inertial Navigation Systems
COURSE OUTLINE, SAMPLERS, AND NOTES
Determine for yourself the value of our courses before you sign up. See our samples (See Slide Samples) on some of our courses.
Or check out the new ATI channel on YouTube.
After attending the course you will receive a full set of detailed notes from the class for future reference, as well as a certificate of completion. Please visit our website for more valuable information.
DATES, TIMES AND LOCATIONS
For the dates and locations of all of our short courses, please access the links below.
Sincerely,
The ATI Courses Team
P.S. Call today for registration at 410-956-8805 or 888-501-2100 or access our website at www.ATIcourses.com. For general questions please email us at ATI@ATIcourses.com.
Washington, DC Monday, November 29, 2010 Is One of These Yours? Video Clip: Click to Watch When Did You Last do Something for Your Career? Since 1984, the Applied Technology Institute (ATI) has provided leading-edge public courses and onsite technical training to DoD and NASA personnel, as well as contractors. Our courses provide a practical overview of space […]
Since 1984, the Applied Technology Institute (ATI) has provided leading-edge public courses and onsite technical training to DoD and NASA personnel, as well as contractors. Our courses provide a practical overview of space and defense technologies which provide a strong foundation for understanding the issues that must be confronted in the use, regulation and development such complex systems.
ATI short courses are designed to help you keep your professional knowledge up-to-date.
Our short courses are designed for individuals involved in planning, designing, building, launching, and operating space and defense systems.
Whether you are a busy engineer, a technical expert or a project manager, you can enhance your understanding of complex systems in a short time. You will become aware of the basic vocabulary essential to interact meaningfully with your colleagues.
Course Outline, Samplers, and Notes
Determine for yourself the value of our courses before you sign up. See our samples (See Slide Samples) on some of our courses.
Or check out the new ATI channel on YouTube.
After attending the course you will receive a full set of detailed notes from the class for future reference, as well as a certificate of completion. Please visit our website for more valuable information.
About ATI and the Instructors
Our mission here at the Applied Technology Institute (ATI) is to provide expert training and the highest quality professional development in space, communications, defense, sonar, radar, and signal processing. We are not a one-size-fits-all educational facility. Our short classes include both introductory and advanced courses.
ATI’s instructors are world-class experts who are the best in the business. They are carefully selected for their ability to clearly explain advanced technology.
Dates, Times and Locations
For the dates and locations of all of our short courses, please access the links below.
Sincerely,
The ATI Courses Team
P.S Call today for registration at 410-956-8805 or 888-501-2100 or access our website at www.ATIcourses.com. For general questions please email us at ATI@ATIcourses.com.
The White House, Senate and House policy guidelines all provide for a total NASA budget of about $19 billion, but each provides different and conflicting directions . The House committee, chaired by Rep. Bart Gordon, D-Tenn., directs NASA to build upon $9 billion already invested in the Constellation program, which the White House proposed terminating […]
The White House, Senate and House policy guidelines all provide for a total NASA budget of about $19 billion, but each provides different and conflicting directions .
The House committee, chaired by Rep. Bart Gordon, D-Tenn., directs NASA to build upon $9 billion already invested in the Constellation program, which the White House proposed terminating in its February budget request for fiscal year 2011.
“In an environment of constrained budgets, responsible stewardship of taxpayer-provided resources makes it imperative that NASA’s exploration program be carried out in a manner that builds on the investments made to date in the Orion, Ares 1 and heavy-lift projects,” the draft bill says.
The draft bill also calls for NASA to develop a heavy-lift rocket by the end of this decade.
http://spaceflightnow.com/news/n1007/20house/
If you enjoyed this information:
“Houston, we have a problem.” “Say again, Apollo 13.” “We have a problem.” It was a problem all right! Seconds before, a violent explosion had ripped through the Apollo Service Module, knocking out two of its three fuel cells and dumping the astronauts’ precious oxygen supplies into black space. At first they managed to remain […]
“Houston, we have a problem.”
“Say again, Apollo 13.”
“We have a problem.”
It was a problem all right! Seconds before, a violent explosion had ripped through the Apollo Service Module, knocking out two of its three fuel cells and dumping the astronauts’ precious oxygen supplies into black space. At first they managed to remain fairly calm, but as their crippled spacecraft hurtled on toward the moon, a fresh crisis suddenly unfolded: The lithium hydroxide canisters in the LEM (Lunar Excursion Module) and the Service Module turned out to be noninterchangeable, and as a result, the air the astronauts were breathing was rapidly becoming polluted. Fortunately, they were able to patch together a workable connection to the canisters in the Service Module, thus making them usable in their overcrowded “lifeboat” LEM. During the next few years other astronauts successfully achieved a number of other spectacular spaceborne repairs, thus proving that astronauts were definitely not merely along for the ride of “Spam in a can” as a cynical journalist once wryly observed. When the micrometeoroid shield was ripped off the main body of the Skylab, for instance, the astronauts erected a big cooling parasol to shield themselves from the burning rays of the sun. On the next mission, astronauts Jack R. Lousma and Owen K. Garriott remodeled the Skylab’s parasol sunshade by erecting two 55-foot metal poles to form a large A-frame tent over their freshly occupied home in space. Other Skylab astronauts repaired an ailing battery, retrieved exposed film from the Apollo telescope mount, and removed and replaced several gyroscopes used in stabilizing their wobbling craft. These complicated tasks were all performed in full space suits outside the protective envelope of the Skylab modules.
The retrieval and redeployment of the Solar Max satellite — which was filmed with IMAX cameras operated by other space shuttle astronauts — provides another powerful illustration of the skill and dexterity of humans in space.Ì Space-age robots have also performed in a similarly impressive manner. For instance, when the television camera mounted on the elbow of the shuttle’s 50-foot robot arm sent back pictures of a big chunk of ice growing on the outside of the waste-water vent on the shuttle orbiter, the Canadian robot arm helped the astronauts execute a clever solution. Rather than risk possible damage to the shuttle’s delicate heat shield, should chunks of the ice break loose during reentry the astronauts were instructed to use the robot arm like a big, heavy trip hammer to knock the ice loose.
On another mission, the robot arm was ready to release the Earth Radiation Budget Satellite into the blackness of space. Unfortunately, during deployment, its solar arrays got stuck in an awkward position so the astronauts used the robot arm to shake the satellite vigorously. Then they held it up to the warming rays of the sun so its solar array could unfold.
The charts provide a basis for engagement with outside organizations, including international entities, industry, academia and other government agencies. Involving outside groups helps NASA make informed decisions as program objectives and expectations are established. To view workshop presentations, visit: http://www.nasa.gov/exploration/new_space_enterprise/home/workshop_home.html Day 1 briefings will be made available below in PDF format and Day 1 video […]
The charts provide a basis for engagement with outside organizations, including international entities, industry, academia and other government agencies. Involving outside groups helps NASA make informed decisions as program objectives and expectations are established. To view workshop presentations, visit:
http://www.nasa.gov/exploration/new_space_enterprise/home/workshop_home.html
Day 1 briefings will be made available below in PDF format and Day 1 video will be made available within one week.
A New Space Enterprise
(PDF, 9.7 MB)Chris Moore (PDF, 2.5 MB)
Exploration Technology Development & Demonstration (ETDD);
Heavy Lift & Propulsion Technology (HL&PT)
> Cris Guidi (PDF, 840 KB)
Flagship Technology Demonstrations (FTD)
> Mike Conley (PDF, 8.7 MB)
Explorations Precursor Robotic Missions (xPRM)
> Jay Jenkins (PDF, 2.2 MB)
Commercial Crew (CC)
> Phil McAlister (PDF, 455 KB)
Participatory Exploration (PE)
> Kathy Nado (PDF, 500 KB)
Panel Q&A/ Wrap-Up
> Mike Conley, Douglas Cooke, Cris Guidi, Michael Hecker, Jay Jenkins, Laurie Leshin, Phil McAlister, Chris Moore, Kathy Nado
If you enjoyed this information:
Freddy posed the following question to Dr. Robert A. Nelson: Dear Dr. Nelson: I understand that GEO satellites are 2 degree appart in its orbital position. How is possible that some satellites ( Telstar 11N and NSS 10 located at 37.5W; Astra 2C and 1D at 31.5 E) occupied the same orbital position ?. Could […]
Freddy posed the following question to Dr. Robert A. Nelson:
Dear Dr. Nelson: I understand that GEO satellites are 2 degree appart in its orbital position. How is possible that some satellites ( Telstar 11N and NSS 10 located at 37.5W; Astra 2C and 1D at 31.5 E) occupied the same orbital position ?. Could you please, help me to understand this ?.
Thank you Dr. Nelson.
Dr. Nelson responded as follows:
The two-degree spacing requirement applies to satellites that use the same
frequencies at C-band or Ku-band. Interference is avoided through the use
of highly directional Earth Station antennas, although there is inevitably
some adjacent satellite interference, with a C/I typically around 22 dB.
Satellites that share the same orbital slot use different frequency bands
and sometimes also different polarizations. For example, at 101 degrees WL,
there are several satellites, including an SES Americom C/Ku-band satellite,
an MSAT L-band satellite, and three or four DirectTV satellites that use a
special portion of Ku-band for DBS and also use different polarizations.
These satellites are separated by only about 0.02 degrees, or about 15
kilometers. Very exact stationkeeping must be maintained.
Dr. Nelson’s Satellite Communication Systems Engieering course is next scheduled December 8-10, 2009 in Beltsville, MD.
The Global Positioning System A National Resource by Robert A. Nelson On a recent trip to visit the Jet Propulsion Laboratory, I flew from Washington, DC to Los Angeles on a new Boeing 747-400 airplane. The geographical position of the plane and its relation to nearby cities was displayed throughout the flight on a video […]
The Global Positioning System
A National Resource
by Robert A. Nelson
On a recent trip to visit the Jet Propulsion Laboratory, I flew from Washington, DC to Los Angeles on a new Boeing 747-400 airplane. The geographical position of the plane and its relation to nearby cities was displayed throughout the flight on a video screen in the passenger cabin. When I arrived in Los Angeles, I rented a car that was equipped with a navigator. The navigator guided me to my hotel in Pasadena, displaying my position on a map and verbally giving me directions with messages like “freeway exit ahead on the right followed by a left turn.” When I reached the hotel, it announced that I had arrived at my destination. Later, when I was to join a colleague for dinner, I found the restaurant listed in a menu and the navigator took me there.
This remarkable navigation capability is made possible by the Global Positioning System (GPS). It was originally designed jointly by the U.S. Navy and the U.S. Air Force to permit the determination of position and time for military troops and guided missiles. However, GPS has also become the basis for position and time measurement by scientific laboratories and a wide spectrum of applications in a multi-billion dollar commercial industry. Roughly one million receivers are manufactured each year and the total GPS market is expected to approach $ 10 billion by the end of next year. The story of GPS and its principles of measurement are the subjects of this article.
EARLY METHODS OF NAVIGATION
The shape and size of the earth has been known from the time of antiquity. The fact that the earth is a sphere was well known to educated people as long ago as the fourth century BC. In his book On the Heavens, Aristotle gave two scientifically correct arguments. First, the shadow of the earth projected on the moon during a lunar eclipse appears to be curved. Second, the elevations of stars change as one travels north or south, while certain stars visible in Egypt cannot be seen at all from Greece.
The actual radius of the earth was determined within one percent by Eratosthenes in about 230 BC. He knew that the sun was directly overhead at noon on the summer solstice in Syene (Aswan, Egypt), since on that day it illuminated the water of a deep well. At the same time, he measured the length of the shadow cast by a column on the grounds of the library at Alexandria, which was nearly due north. The distance between Alexandria and Syene had been well established by professional runners and camel caravans. Thus Eratosthenes was able to compute the earth’s radius from the difference in latitude that he inferred from his measurement. In terms of modern units of length, he arrived at the figure of about 6400 km. By comparison, the actual mean radius is 6371 km (the earth is not precisely spherical, as the polar radius is 21 km less than the equatorial radius of 6378 km).
The ability to determine one’s position on the earth was the next major problem to be addressed. In the second century, AD the Greek astronomer Claudius Ptolemy prepared a geographical atlas, in which he estimated the latitude and longitude of principal cities of the Mediterranean world. Ptolemy is most famous, however, for his geocentric theory of planetary motion, which was the basis for astronomical catalogs until Nicholas Copernicus published his heliocentric theory in 1543.
Historically, methods of navigation over the earth’s surface have involved the angular measurement of star positions to determine latitude. The latitude of one’s position is equal to the elevation of the pole star. The position of the pole star on the celestial sphere is only temporary, however, due to precession of the earth’s axis of rotation through a circle of radius 23.5 over a period of 26,000 years. At the time of Julius Caesar, there was no star sufficiently close to the north celestial pole to be called a pole star. In 13,000 years, the star Vega will be near the pole. It is perhaps not a coincidence that mariners did not venture far from visible land until the era of Christopher Columbus, when true north could be determined using the star we now call Polaris. Even then the star’s diurnal rotation caused an apparent variation of the compass needle. Polaris in 1492 described a radius of about 3.5 about the celestial pole, compared to 1 today. At sea, however, Columbus and his contemporarie s depended primarily on the mariner’s compass and dead reckoning.
The determination of longitude was much more difficult. Longitude is obtained astronomically from the difference between the observed time of a celestial event, such as an eclipse, and the corresponding time tabulated for a reference location. For each hour of difference in time, the difference in longitude is 15 degrees.
Columbus himself attempted to estimate his longitude on his fourth voyage to the New World by observing the time of a lunar eclipse as seen from the harbor of Santa Gloria in Jamaica on February 29, 1504. In his distinguished biography Admiral of the Ocean Sea, Samuel Eliot Morrison states that Columbus measured the duration of the eclipse with an hour-glass and determined his position as nine hours and fifteen minutes west of Cadiz, Spain, according to the predicted eclipse time in an almanac he carried aboard his ship. Over the preceding year, while his ship was marooned in the harbor, Columbus had determined the latitude of Santa Gloria by numerous observations of the pole star. He made out his latitude to be 18, which was in error by less than half a degree and was one of the best recorded observations of latitude in the early sixteenth century, but his estimated longitude was off by some 38 degrees.
Columbus also made legendary use of this eclipse by threatening the natives with the disfavor of God, as indicated by a portent from Heaven, if they did not bring desperately needed provisions to his men. When the eclipse arrived as predicted, the natives pleaded for the Admiral’s intervention, promising to furnish all the food that was needed.
New knowledge of the universe was revealed by Galileo Galilei in his book The Starry Messenger. This book, published in Venice in 1610, reported the telescopic discoveries of hundreds of new stars, the craters on the moon, the phases of Venus, the rings of Saturn, sunspots, and the four inner satellites of Jupiter. Galileo suggested using the eclipses of Jupiter’s satellites as a celestial clock for the practical determination of longitude, but the calculation of an accurate ephemeris and the difficulty of observing the satellites from the deck of a rolling ship prevented use of this method at sea. Nevertheless, James Bradley, the third Astronomer Royal of England, successfully applied the technique in 1726 to determine the longitudes of Lisbon and New York with considerable accuracy.
Inability to measure longitude at sea had the potential of catastrophic consequences for sailing vessels exploring the new world, carrying cargo, and conquering new territories. Shipwrecks were common. On October 22, 1707 a fleet of twenty-one ships under the command of Admiral Sir Clowdisley Shovell was returning to England after an unsuccessful military attack on Toulon in the Mediterranean. As the fleet approached the English Channel in dense fog, the flagship and three others foundered on the coastal rocks and nearly two thousand men perished.
Stunned by this unprecedented loss, the British government in 1714 offered a prize of £20,000 for a method to determine longitude at sea within a half a degree. The scientific establishment believed that the solution would be obtained from observations of the moon. The German cartographer Tobias Mayer, aided by new mathematical methods developed by Leonard Euler, offered improved tables of the moon in 1757. The recorded position of the moon at a given time as seen from a reference meridian could be compared with its position at the local time to determine the angular position west or east.
Just as the astronomical method appeared to achieve realization, the British craftsman John Harrison provided a different solution through his invention of the marine chronometer. The story of Harrison’s clock has been recounted in Dava Sobel’s popular book, Longitude.
Both methods were tested by sea trials. The lunar tables permitted the determination of longitude within four minutes of arc, but with Harrison’s chronometer the precision was only one minute of arc. Ultimately, portions of the prize money were awarded to Mayer’s widow, Euler, and Harrison.
In the twentieth century, with the development of radio transmitters, another class of navigation aids was created using terrestrial radio beacons, including Loran and Omega. Finally, the technology of artificial satellites made possible navigation and position determination using line of sight signals involving the measurement of Doppler shift or phase difference.
TRANSIT
Transit, the Navy Navigation Satellite System, was conceived in the late 1950s and deployed in the mid-1960s. It was finally retired in 1996 after nearly 33 years of service. The Transit system was developed because of the need to provide accurate navigation data for Polaris missile submarines. As related in an historical perspective by Bradford Parkinson, et al. in the journal Navigation (Spring 1995), the concept was suggested by the predictable but dramatic Doppler frequency shifts from the first Sputnik satellite, launched by the Soviet Union in October, 1957. The Doppler-shifted signals enabled a determination of the orbit using data recorded at one site during a single pass of the satellite. Conversely, if a satellite’s orbit were already known, a radio receiver’s position could be determined from the same Doppler measurements.
The Transit system was composed of six satellites in nearly circular, polar orbits at an altitude of 1075 km. The period of revolution was 107 minutes. The system employed essentially the same Doppler data used to track the Sputnik satellite. However, the orbits of the Transit satellites were precisely determined by tracking them at widely spaced fixed sites. Under favorable conditions, the rms accuracy was 35 to 100 meters. The main problem with Transit was the large gaps in coverage. Users had to interpolate their positions between passes.
GLOBAL POSITIONING SYSTEM
The success of Transit stimulated both the U.S. Navy and the U.S. Air Force to investigate more advanced versions of a space-based navigation system with enhanced capabilities. Recognizing the need for a combined effort, the Deputy Secretary of Defense established a Joint Program Office in 1973. The NAVSTAR Global Positioning System (GPS) was thus created.
In contrast to Transit, GPS provides continuous coverage. Also, rather than Doppler shift, satellite range is determined from phase difference.
There are two types of observables. One is pseudorange, which is the offset between a pseudorandom noise (PRN) coded signal from the satellite and a replica code generated in the user’s receiver, multiplied by the speed of light. The other is accumulated delta range (ADR), which is a measure of carrier phase.
The determination of position may be described as the process of triangulation using the measured range between the user and four or more satellites. The ranges are inferred from the time of propagation of the satellite signals. Four satellites are required to determine the three coordinates of position and time. The time is involved in the correction to the receiver clock and is ultimately eliminated from the measurement of position.
High precision is made possible through the use of atomic clocks carried on-board the satellites. Each satellite has two cesium clocks and two rubidium clocks, which maintain time with a precision of a few parts in 1013 or 1014 over a few hours, or better than 10 nanoseconds. In terms of the distance traversed by an electromagnetic signal at the speed of light, each nanosecond corresponds to about 30 centimeters. Thus the precision of GPS clocks permits a real time measurement of distance to within a few meters. With post-processed carrier phase measurements, a precision of a few centimeters can be achieved.
The design of the GPS constellation had the fundamental requirement that at least four satellites must be visible at all times from any point on earth. The tradeoffs included visibility, the need to pass over the ground control stations in the United States, cost, and sparing efficiency.
The orbital configuration approved in 1973 was a total of 24 satellites, consisting of 8 satellites plus one spare in each of three equally spaced orbital planes. The orbital radius was 26,562 km, corresponding to a period of revolution of 12 sidereal hours, with repeating ground traces. Each satellite arrived over a given point four minutes earlier each day. A common orbital inclination of 63 was selected to maximize the on-orbit payload mass with launches from the Western Test Range. This configuration ensured between 6 and 11 satellites in view at any time.
As envisioned ten years later, the inclination was reduced to 55 and the number of planes was increased to six. The constellation would consist of 18 primary satellites, which represents the absolute minimum number of satellites required to provide continuous global coverage with at least four satellites in view at any point on the earth. In addition, there would be 3 on-orbit spares.
The operational system, as presently deployed, consists of 21 primary satellites and 3 on-orbit spares, comprising four satellites in each of six orbital planes. Each orbital plane is inclined at 55. This constellation improves on the “18 plus 3” satellite constellation by more fully integrating the three active spares.
SPACE SEGMENT
There have been several generations of GPS satellites. The Block I satellites, built by Rockwell International, were launched between 1978 and 1985. They consisted of eleven prototype satellites, including one launch failure, that validated the system concept. The ten successful satellites had an average lifetime of 8.76 years.
The Block II and Block IIA satellites were also built by Rockwell International. Block II consists of nine satellites launched between 1989 and 1990. Block IIA, deployed between 1990 and 1997, consists of 19 satellites with several navigation enhancements. In April 1995, GPS was declared fully operational with a constellation of 24 operational spacecraft and a completed ground segment. The 28 Block II/IIA satellites have exceeded their specified mission duration of 6 years and are expected to have an average lifetime of more than 10 years.
Block IIR comprises 20 replacement satellites that incorporate autonomous navigation based on crosslink ranging. These satellites are being manufactured by Lockheed Martin. The first launch in 1997 resulted in a launch failure. The first IIR satellite to reach orbit was also launched in 1997. The second GPS 2R satellite was successfully launched aboard a Delta 2 rocket on October 7, 1999. One to four more launches are anticipated over the next year.
The fourth generation of satellites is the Block II follow-on (Block IIF). This program includes the procurement of 33 satellites and the operation and support of a new GPS operational control segment. The Block IIF program was awarded to Rockwell (now a part of Boeing). Further details may be found in a special issue of the Proceedings of the IEEE for January, 1999.
CONTROL SEGMENT
The Master Control Station for GPS is located at Schriever Air Force Base in Colorado Springs, CO. The MCS maintains the satellite constellation and performs the stationkeeping and attitude control maneuvers. It also determines the orbit and clock parameters with a Kalman filter using measurements from five monitor stations distributed around the world. The orbit error is about 1.5 meters.
GPS orbits are derived independently by various scientific organizations using carrier phase and post-processing. The state of the art is exemplified by the work of the International GPS Service (IGS), which produces orbits with an accuracy of approximately 3 centimeters within two weeks.
The system time reference is managed by the U.S. Naval Observatory in Washington, DC. GPS time is measured from Saturday/Sunday midnight at the beginning of the week. The GPS time scale is a composite “paper clock” that is synchronized to keep step with Coordinated Universal Time (UTC) and International Atomic Time (TAI). However, UTC differs from TAI by an integral number of leap seconds to maintain correspondence with the rotation of the earth, whereas GPS time does not include leap seconds. The origin of GPS time is midnight on January 5/6, 1980 (UTC). At present, TAI is ahead of UTC by 32 seconds, TAI is ahead of GPS by 19 seconds, and GPS is ahead of UTC by 13 seconds. Only 1,024 weeks were allotted from the origin before the system time is reset to zero because 10 bits are allocated for the calendar function (1,024 is the tenth power of 2). Thus the first GPS rollover occurred at midnight on August 21, 1999. The next GPS rollover will take place May 25, 2019.
SIGNAL STRUCTURE
The satellite position at any time is computed in the user’s receiver from the navigation message that is contained in a 50 bps data stream. The orbit is represented for each one hour period by a set of 15 Keplerian orbital elements, with harmonic coefficients arising from perturbations, and is updated every four hours.
This data stream is modulated by each of two code division multiple access, or spread spectrum, pseudorandom noise (PRN) codes: the coarse/acquisition C/A code (sometimes called the clear/access code) and the precision P code. The P code can be encrypted to produce a secure signal called the Y code. This feature is known as the Anti-Spoof (AS) mode, which is intended to defeat deception jamming by adversaries. The C/A code is used for satellite acquisition and for position determination by civil receivers. The P(Y) code is used by military and other authorized receivers.
The C/A code is a Gold code of register size 10, which has a sequence length of 1023 chips and a chipping rate of 1.023 MHz and thus repeats itself every 1 millisecond. (The term “chip” is used instead of “bit” to indicate that the PRN code contains no information.) The P code is a long code of length 2.3547 x 1014 chips with a chipping rate of 10 times the C/A code, or 10.23 MHz. At this rate, the P code has a period of 38.058 weeks, but it is truncated on a weekly basis so that 38 segments are available for the constellation. Each satellite uses a different member of the C/A Gold code family and a different one-week segment of the P code sequence.
The GPS satellites transmit signals at two carrier frequencies: the L1 component with a center frequency of 1575.42 MHz, and the L2 component with a center frequency of 1227.60 MHz. These frequencies are derived from the master clock frequency of 10.23 MHz, with L1 = 154 x 10.23 MHz and L2 = 120 x 10.23 MHz. The L1 frequency transmits both the P code and the C/A code, while the L2 frequency transmits only the P code. The second P code frequency permits a dual-frequency measurement of the ionospheric group delay. The P-code receiver has a two-sigma rms horizontal position error of about 5 meters.
The single frequency C/A code user must model the ionospheric delay with less accuracy. In addition, the C/A code is intentionally degraded by a technique called Selective Availability (SA), which introduces errors of 50 to 100 meters by dithering the satellite clock data. Through differential GPS measurements, however, position accuracy can be improved by reducing SA and environmental errors.
The transmitted signal from a GPS satellite has right hand circular polarization. According to the GPS Interface Control Document, the specified minimum signal strength at an elevation angle of 5 into a linearly polarized receiver antenna with a gain of 3 dB (approximately equivalent to a circularly polarized antenna with a gain of 0 dB) is – 160 dBW for the L1 C/A code, – 163 dBW for the L1 P code, and – 166 dBW for the L2 P code. The L2 signal is transmitted at a lower power level since it is used primarily for the ionospheric delay correction.
PSEUDORANGE
The fundamental measurement in the Global Positioning System is pseudorange. The user equipment receives the PRN code from a satellite and, having identified the satellite, generates a replica code. The phase by which the replica code must be shifted in the receiver to maintain maximum correlation with the satellite code, multiplied by the speed of light, is approximately equal to the satellite range. It is called the pseudorange because the measurement must be corrected by a variety of factors to obtain the true range.
The corrections that must be applied include signal propagation delays caused by the ionosphere and the troposphere, the space vehicle clock error, and the user’s receiver clock error. The ionosphere correction is obtained either by measurement of dispersion using the two frequencies L1 and L2 or by calculation from a mathematical model, but the tropospheric delay must be calculated since the troposphere is nondispersive. The true geometric distance to each satellite is obtained by applying these corrections to the measured pseudorange.
Other error sources and modeling errors continue to be investigated. For example, a recent modification of the Kalman filter has led to improved performance. Studies have also shown that solar radiation pressure models may need revision and there is some new evidence that the earth’s magnetic field may contribute to a small orbit period variation in the satellite clock frequencies.
CARRIER PHASE
Carrier phase is used to perform measurements with a precision that greatly exceeds those based on pseudorange. However, a carrier phase measurement must resolve an integral cycle ambiguity whereas the pseudorange is unambiguous.
The wavelength of the L1 carrier is about 19 centimeters. Thus with a cycle resolution of one percent, a differential measurement at the level of a few millimeters is theoretically possible. This technique has important applications to geodesy and analogous scientific programs.
RELATIVITY
The precision of GPS measurements is so great that it requires the application of Albert Einstein’s special and general theories of relativity for the reduction of its measurements. Professor Carroll Alley of the University of Maryland once articulated the significance of this fact at a scientific conference devoted to time measurement in 1979. He said, “I think it is appropriate … to realize that the first practical application of Einstein’s ideas in actual engineering situations are with us in the fact that clocks are now so stable that one must take these small effects into account in a variety of systems that are now undergoing development or are actually in use in comparing time worldwide. It is no longer a matter of scientific interest and scientific application, but it has moved into the realm of engineering necessity.”
According to relativity theory, a moving clock appears to run slow with respect to a similar clock that is at rest. This effect is called “time dilation.” In addition, a clock in a weaker gravitational potential appears to run fast in comparison to one that is in a stronger gravitational potential. This gravitational effect is known in general as the “red shift” (only in this case it is actually a “blue shift”).
GPS satellites revolve around the earth with a velocity of 3.874 km/s at an altitude of 20,184 km. Thus on account of the its velocity, a satellite clock appears to run slow by 7 microseconds per day when compared to a clock on the earth’s surface. But on account of the difference in gravitational potential, the satellite clock appears to run fast by 45 microseconds per day. The net effect is that the clock appears to run fast by 38 microseconds per day. This is an enormous rate difference for an atomic clock with a precision of a few nanoseconds. Thus to compensate for this large secular rate, the clocks are given a rate offset prior to satellite launch of – 4.465 parts in 1010 from their nominal frequency of 10.23 MHz so that on average they appear to run at the same rate as a clock on the ground. The actual frequency of the satellite clocks before launch is thus 10.22999999543 MHz.
Although the GPS satellite orbits are nominally circular, there is always some residual eccentricity. The eccentricity causes the orbit to be slightly elliptical, and the velocity and altitude vary over one revolution. Thus, although the principal velocity and gravitational effects have been compensated by a rate offset, there remains a slight residual variation that is proportional to the eccentricity. For example, with an orbital eccentricity of 0.02 there is a relativistic sinusoidal variation in the apparent clock time having an amplitude of 46 nanoseconds. This correction must be calculated and taken into account in the GPS receiver.
The displacement of a receiver on the surface of the earth due to the earth’s rotation in inertial space during the time of flight of the signal must also be taken into account. This is a third relativistic effect that is due to the universality of the speed of light. The maximum correction occurs when the receiver is on the equator and the satellite is on the horizon. The time of flight of a GPS signal from the satellite to a receiver on the earth is then 86 milliseconds and the correction to the range measurement resulting from the receiver displacement is 133 nanoseconds. An analogous correction must be applied by a receiver on a moving platform, such as an aircraft or another satellite. This effect, as interpreted by an observer in the rotating frame of reference of the earth, is called the Sagnac effect. It is also the basis for a laser ring gyro in an inertial navigation system.
GPS MODERNIZATION
In 1996, a Presidential Decision Directive stated the president would review the issue of Selective Availability in 2000 with the objective of discontinuing SA no later than 2006. In addition, both the L1 and L2 GPS signals would be made available to civil users and a new civil 10.23 MHz signal would be authorized. To satisfy the needs of aviation, the third civil frequency, known as L5, would be centered at 1176.45 MHz, in the Aeronautical Radio Navigation Services (ARNS) band, subject to approval at the World Radio Conference in 2000. According to Keith McDonald in an article on GPS modernization published in the September, 1999 GPS World, with SA removed the civil GPS accuracy would be improved to about 10 to 30 meters. With the addition of a second frequency for ionospheric group delay corrections, the civil accuracy would become about 5 to 10 meters. A third frequency would permit the creation of two beat frequencies that would yield one-meter accuracy in real time.
A variety of other enhancements are under consideration, including increased power, the addition of a new military code at the L1 and L2 frequencies, additional ground stations, more frequent uploads, and an increase in the number of satellites. These policy initiatives are driven by the dual needs of maintaining national security while supporting the growing dependence on GPS by commercial industry. When these upgrades would begin to be implemented in the Block IIR and IIF satellites depends on GPS funding.
Besides providing position, GPS is a reference for time with an accuracy of 10 nanoseconds or better. Its broadcast time signals are used for national defense, commercial, and scientific purposes. The precision and universal availability of GPS time has produced a paradigm shift in time measurement and dissemination, with GPS evolving from a secondary source to a fundamental reference in itself.
The international community wants assurance that it can rely on the availability of GPS and continued U.S. support for the system. The Russian Global Navigation Satellite System (GLONASS) has been an alternative, but economic conditions in Russia have threatened its continued viability. Consequently, the European Union is considering the creation of a navigation system of its own, called Galileo, to avoide relying on the U.S. GPS and Russian GLONASS programs.
The Global Positioning System is a vital national resource. Over the past thirty years it has made the transition from concept to reality, representing today an operational system on which the entire world has become dependent. Both technical improvements and an enlightened national policy will be necessary to ensure its continued growth into the twenty-first century.
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Dr. Robert A. Nelson, P.E. is president of Satellite Engineering Research Corporation, a satellite engineering consulting firm in Bethesda, Maryland, a Lecturer in the Department of Aerospace Engineering at the University of Maryland and Technical Editor of Via Satellite magazine. Dr. Nelson is the instructor for the ATI course Satellite Communications Systems Engineering. Please see our Schedule for dates and locations.
On the 23rd day of this month, a revolutionary communication system will begin service to the public. Iridium will be the first mobile telephony system to offer voice and data services to and from handheld telephones anywhere in the world. Industry analysts have eagerly awaited this event, as they have debated the nature of the […]
On the 23rd day of this month, a revolutionary communication system will begin service to the public. Iridium will be the first mobile telephony system to offer voice and data services to and from handheld telephones anywhere in the world. Industry analysts have eagerly awaited this event, as they have debated the nature of the market, the economics, and the technical design.
As with any complex engineering system, credit must be shared among many people. However, the three key individuals who are recognized as having conceived and designed the system are Bary Bertiger,
Dr. Raymond Leopold, and Kenneth Peterson of Motorola, creators of the Iridium system.
The inspiration was an occasion that has entered into the folklore of Motorola. (The story, as recounted here, was the subject of a Wall Street Journal profile on Monday, December 16, 1996.) On a vacation to the Bahamas in 1985, Bertiger’s wife, Karen, wanted to place a cellular telephone call back to her home near the Motorola facility in Chandler, AZ to close a real-estate transaction. After attempting to make the connection without success, she asked Bertiger why it wouldn’t be possible to create a telephone system that would work anywhere, even in the remote Caribbean outback.
Bertiger took the problem back to colleagues Leopold and Peterson at Motorola. Numerous alternative terrestrial designs were discussed and abandoned.
In 1987 research began on a constellation of low earth orbiting satellites that could communicate directly with telephones on the ground and with one another — a kind of inverted cellular telephone system.
But as they left work one day in 1988, Leopold proposed a crucial element of the design. The satellites would be coordinated by a network of “gateway” earth stations connecting the satellite system to existing telephone systems. They quickly agreed that this was the sought-after solution and immediately wrote down an outline using the nearest available medium — a whiteboard in a security guard’s office.
Originally, the constellation was to have consisted of 77 satellites. The constellation was based on a study by William S. Adams and Leonard Rider of the Aerospace Corporation, who published a paper in The Journal of the Astronautical Sciences in 1987 on the configurations of circular, polar satellite constellations at various altitudes providing continuous, full-earth coverage with a minimum number of satellites. However, by 1992 several modifications had been made to the system, including a reduction in the number of satellites from 77 to 66 by the elimination of one orbital plane.
The name Iridium was suggested by a Motorola cellular telephone system engineer, Jim Williams, from the Motorola facility near Chicago. The 77-satellite constellation reminded him of the electrons that encircle the nucleus in the classical Bohr model of the atom. When he consulted the periodic table of the elements to discover which atom had 77 electrons, he found Iridium — a creative name that has a nice ring. Fortunately, the system had not yet been scaled back to 66 satellites, or else he might have suggested the name Dysprosium.
The project was not adopted by senior management immediately. On a visit to the Chandler facility, however, Motorola chairman Robert Galvin learned of the idea and was briefed by Bertiger. Galvin at once endorsed the plan and at a subsequent meeting persuaded Motorola’s president John Mitchell. Ten years have elapsed from this go-ahead decision, and thirteen years since Bertiger’s wife posed the question.
In December 1997 the first Iridium test call was delivered by orbiting satellites. Shortly after completion of the constellation in May 1998, a demonstration was conducted for franchise owners and guests. The new system was ready for operation, and Iridium is now on the threshold of beginning service.
REGULATORY HURDLES
In June, 1990 Motorola announced the development of its Iridium satellite system at simultaneous press conferences in Beijing, London, Melbourne, and New York. The Iridium system was described in an application to the Federal Communications Commission (FCC) filed in December of that year, in a supplement of February 1991, and an amendment in August 1992.
At the time, an internationally allocated spectrum for this service by nongeostationary satellites did not even exist. Thus Motorola proposed to offer Radio Determination Satellite Service (RDSS) in addition to mobile digital voice and data communication so that it might qualify for use of available spectrum in the RDSS
L-band from 1610 to 1626.5 MHz. A waiver was requested to provide both two-way digital voice and data services on a co-primary basis with RDSS.
Following the submission of Motorola’s Iridium proposal, the FCC invited applications from other companies for systems to share this band for the new Mobile Satellite Service (MSS). An additional four proposals for nongeostationary mobile telephony systems were submitted to meet the June 3, 1991 deadline, including Loral/Qualcomm’s Globalstar, TRW’s Odyssey, MCHI’s Ellipsat, and Constellation Communications’ Aries. Collectively, these nongeostationary satellite systems became known as the “Big LEOs”. The American Mobile Satellite Corporation (AMSC) also sought to expand existing spectrum for its geostationary satellite into the RDSS band.
At the 1992 World Administrative Radio Conference (WARC-92) in Torremolinos, Spain, L-band spectrum from 1610 to 1626.5 MHz was internationally allocated for MSS for earth-to-space (uplink) on a primary basis in all three ITU regions. WARC-92 also allocated to MSS the band 1613.8 to 1626.5 MHz on a secondary basis and spectrum in S-band from 2483.5 to 2500 MHz on a primary basis for space-to-earth (downlink).
In early 1993 the FCC adopted a conforming domestic spectrum allocation and convened a Negotiated Rulemaking proceeding. This series of meetings was attended in Washington, DC by representatives of the six applicants and Celsat, which had expressed an intention to file an application for a geostationary satellite but did not meet the deadline.
The purpose of the proceeding was to provide the companies with the opportunity to devise a frequency- sharing plan and make recommendations. These deliberations were lively, and at times contentious, as Motorola defended its FDMA/TDMA multiple access design against the CDMA technologies of the other participants.
With frequency division multiple access (FDMA), the available spectrum is subdivided into smaller bands allocated to individual users. Iridium extends this multiple access scheme further by using time division multiple access (TDMA) within each FDMA sub-band. Each user is assigned two time slots — one for sending and one for receiving — within a repetitive time frame. During each time slot, the digital data are burst between the mobile handset and the satellite.
With code division multiple access (CDMA), the signal from each user is modulated by a pseudorandom noise (PRN) code. All users share the same spectrum. At the receiver, the desired signal is extracted from the entire population of signals by multiplying by a replica code and performing an autocorrelation process. The key to the success of this method is the existence of sufficient PRN codes that appear to be mathematically orthogonal to one another. Major advantages cited by CDMA proponents are inherently greater capacity and higher spectral efficiency. Frequency reuse clusters can be smaller because interference is reduced between neighboring cells.
In April, 1993 a majority report of Working Group 1 of the Negotiated Rulemaking Committee recommended full band sharing across the entire MSS band by all systems including Iridium. Coordination would be based on an equitable allocation of interference noise produced by each system. The FDMA/TDMA system would be assigned one circular polarization and the CDMA systems would be assigned the opposite polarization. This approach required that each system would be designed with sufficient margin to tolerate the level of interference received from other licensed systems.
Motorola issued a minority report which stated that the Iridium system must have its own spectrum allocation. It proposed partitioning of the MSS L-band spectrum into two equal 8.25 MHz segments for the FDMA/TDMA and CDMA access technologies, with the upper portion being used by the FDMA/TDMA system where it would be sufficiently isolated from neighboring frequencies used by radio astronomy, GPS, and Glonass.
Faced with this impasse, the FCC in January 1994 adopted rulemaking proposals which allocated the upper 5.15 MHz of the MSS L-band spectrum to the sole FDMA/TDMA applicant, Iridium, and assigned the remaining 11.35 MHz to be shared by multiple CDMA systems. However, if only one CDMA system were implemented, the 11.35 MHz allotment would be reduced to 8.25 MHz, leaving 3.10 MHz available for additional spectrum to Iridium or a new applicant.
The response to the Commission’s proposals from the Big LEO applicants was generally favorable. Without this compromise, the alternative would have been to hold a lottery or auction to allocate the spectrum. The Iridium system was designed to operate with the full spectrum allocation. However, with 5.15 MHz, the system is a viable business proposition. The additional 3.10 MHz, should it become available, further adds to the system’s attractiveness.
The FCC also proposed that the MSS spectrum could be used only by Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) satellite systems. Therefore, the geostationary orbit (GEO) systems of AMSC and Celsat would not be permitted in this band. To qualify for a Big LEO license, the Commission proposed that the service must be global (excluding the poles) and that companies must meet stringent financial standards.
In October, 1994 the FCC issued its final rules for MSS, closely following language of the January proposed rulemaking. However, it allowed the CDMA systems to share the entire 16.5 MHz of downlink spectrum in S-band. The Commission gave the Big LEO applicants a November 16 deadline to amend their applications to conform to the new licensing rules.
On January 31, 1995 the FCC granted licenses to Iridium, Globalstar, and Odyssey but withheld its decision on Ellipsat and Aries pending an evaluation of their financial qualifications. The latter companies finally received licenses in June last year, while in December TRW dropped its Odyssey system in favor of partnership with ICO, the international subsidiary of Inmarsat which entered the competition in 1995.
Outside the United States, Iridium must obtain access rights in each country where service is provided. The company expects to have reached agreements with 90 priority countries that represent 85% of its business plan by the start of service this month. Altogether, Iridium is seeking access to some 200 countries through an arduous negotiating process.
FINANCING
Iridium LLC was established by Motorola in December, 1991 to build and operate the Iridium system, with Robert W. Kinzie as its chairman. In December, 1996 Edward F. Staiano was appointed Vice Chairman and CEO.
Iridium LLC, based in Washington, DC, is a 19-member international consortium of strategic investors representing telecommuni-cation and industrial companies, including a 25 percent stake by its prime contractor, Motorola, Inc.
In August 1993, Motorola and Iridium LLC announced they had completed the first-round financing of the Iridium system with $800 million in equity. The second round was completed in September, 1994, bringing the total to $1.6 billion. In July of last year $800 million in debt financing was completed. Iridium World Communications, Ltd., a Bermuda company, was formed to serve as a vehicle for public investment in the Iridium system. In June 1997 an initial $240 million public offering was made on the NASDAQ Stock Exchange.
TECHNICAL DESCRIPTION
The Iridium constellation consists of 66 satellites in near-polar circular orbits inclined at 86.4° at an altitude of 780 km. The satellites are distributed into six planes separated by 31.6° around the equator with eleven satellites per plane. There is also one spare satellite in each plane.
Starting on May 5, 1997, the entire constellation was deployed within twelve months on launch vehicles from three continents: the U.S. Delta II, the Russian Proton, and the Chinese Long March. The final complement of five 700 kg (1500 lb) satellites was launched aboard a Delta II rocket on May 17. With a satellite lifetime of from 5 to 8 years, it is expected that the replenishment rate will be about a dozen satellites per year after the second year of operation.
The altitude was specified to be within the range 370 km (200 nmi) and 1100 km (600 nmi). The engineers wanted a minimum altitude of 370 km so that the satellite would be above the residual atmosphere, which would have diminished lifetime without extensive stationkeeping, and a maximum altitude of 1100 km so that the satellite would be below the Van Allen radiation environment, which would require shielding.
Each satellite covers a circular area roughly the size of the United States with a diameter of about 4400 km, having an elevation angle of 8.2° at the perimeter and subtending an angle of 39.8° with respect to the center of the earth. The coverage area is divided into 48 cells. The satellite has three main beam phased array antennas, each of which serves 16 cells.
The period of revolution is approximately 100 minutes, so that a given satellite is in view about 9 minutes. The user is illuminated by a single cell for about one minute. Complex protocols are required to provide continuity of communication seamlessly as handover is passed from cell to cell and from satellite to satellite. The communications link requires 3.5 million lines of software, while an additional 14 million lines of code are required for navigation and switching. As satellites converge near the poles, redundant beams are shut off. There are approximately 2150 active beams over the globe.
The total spectrum of 5.15 MHz is divided into 120 FDMA channels, each with a bandwidth of 31.5 kHz and a guardband of 10.17 kHz to minimize intermodulation effects and two guardbands of 37.5 kHz to allow for Doppler frequency shifts. Within each FDMA channel, there are four TDMA slots in each direction (uplink and downlink). The coded data burst rate with QPSK modulation and raised cosine filtering is 50 kbps (corresponding to an occupied bandwidth of 1.26 ´ 50 kbps / 2 = 31.5 kHz). Each TDMA slot has length 8.29 ms in a 90 ms frame. The supported vocoder information bit rate is 2.4 kbps for digital voice, fax, and data. The total information bit rate, with rate 3/4 forward error correction (FEC) coding, is 3.45 kbps (0.75 ´ (8.28 ms/90 ms) ´ 50 kbps = 3.45 kbps), which includes overhead and source encoding, exclusive of FEC coding, for weighting of parameters in importance of decoding the signal. The bit error ratio (BER) at threshold is nominally 0.01 but is much better 99 percent of the time.
The vocoder is analogous to a musical instrument synthesizer. In this case, the “instrument” is the human vocal tract. Instead of performing analogue-to-digital conversion using pulse code modulation (PCM) with a nominal data rate of 64 kbps (typical of terrestrial toll-quality telephone circuits), the vocoder transmits a set of parameters that emulate speech patterns, vowel sounds, and acoustic level. The resulting bit rate of 2.4 kbps is thus capable of transmitting clear, intelligible speech comparable to the performance of high quality terrestrial cellular telephones, but not quite the quality of standard telephones.
The signal strength has a nominal 16 dB link margin. This margin is robust for users in exterior urban environments, but is not sufficient to penetrate buildings. Satellite users will have to stand near windows or go outside to place a call. Handover from cell to cell within the field of view of an orbiting satellite is imperceptible. Handover from satellite to satellite every nine minutes may occasionally be detectable by a quarter-second gap.
Each satellite has a capacity of about 1100 channels. However, the actual number of users within a satellite coverage area will vary and the distribution of traffic among cells is not symmetrical.
CALL ROUTINGThe Iridium satellites are processing satellites that route a call through the satellite constellation. The system is coordinated by 12 physical gateways distributed around the world, although in principle only a single gateway would be required for complete global coverage. Intersatellite links operate in Ka-band from 23.18 to 23.38 GHz and satellite-gateway links operate in Ka-band at 29.1 to 29.3 GHz (uplink) and 19.4 to 19.6 GHz (downlink).
For example, a gateway in Tempe, Arizona serves North America and Central America; a gateway in Italy serves Europe and Africa; a gateway in India serves southern Asia and Australia. There are 15 regional franchise owners, some of whom share gateway facilities. The constellation is managed from a new satellite network operations center in Lansdowne, Virginia.
As described by Craig Bond, Iridium’s vice president for marketing development, the user dials a telephone number with the handset using an international 13 digit number as one would do normally using a standard telephone. The user presses the “send” button to access the nearest satellite. The system identifies the user’s position and authenticates the handset at the nearest gateway with the home location register (HLR).
Once the user is validated, the call is sent to the satellite. The call is routed through the constellation and drops to the gateway closest to the destination. There it is completed over standard terrestrial circuits.
For a call from a fixed location to a handset, the process is reversed. After the call is placed, the system identifies the recipient’s location and the handset rings, no matter where the user is on the earth.
It is projected that about 95 percent of the traffic will be between a mobile handset and a telephone at a fixed location. The remaining 5 percent of the traffic represents calls placed from one handset to another handset anywhere in the world. In this case, the call “never touches the ground” until it is received by the handset of the intended recipient.
By comparison, a “bent pipe” satellite system, such as Globalstar, requires that a single satellite see both the user and the nearest gateway simultaneously. Thus many more gateways are needed. For example, in Africa Globalstar will require about a dozen gateways, while Iridium has none at all. Globalstar advocates would counter that this is not a disadvantage, since their system places the complexity on the ground rather than the satellite and offers greater flexibility in building and upgrading the system.
HANDSET
The Iridium handsets are built by Motorola and Kyocera, a leading manufacturer of cellular telephones in Japan. Handsets will permit both satellite access and terrestrial cellular roaming capability within the same unit. The unit also includes a Subscriber Identity Module (SIM) card. Major regional cellular standards are interchanged by inserting a Cellular Cassette. Paging options are available, as well as separate compact Iridium pagers.
The price for a typical configuration will be around $3,000. The handsets will be available through service providers and cellular roaming partners. In June, Iridium finalized its 200th local distribution agreement.
Information on how to obtain Iridium telephones will be advertised widely. Customers will also be actively solicited through credit card and travel services memberships. Distribution of the handsets and setup will typically be through sales representatives who will interface with the customer directly. Rental programs will also be available to give potential customers the opportunity to try out the system on a temporary basis.
MARKET
Iridium has conducted extensive research to measure the market. As described by Iridium’s Bond, the intended market can be divided into two segments: the vertical market and the horizontal market.
The vertical market consists of customers in remote areas who require satellites for their communications needs because they cannot access conventional terrestrial cellular networks. This market includes personnel in the petroleum, gas, mining, and shipping industries. It also includes the branches of the U.S. military. In fact, the U.S. government has built a dedicated gateway in Hawaii capable of serving 120,000 users so that it can access the Iridium system at a lower per minute charge.
The horizontal market is represented by the international business traveler. This type of customer wants to keep in contact with the corporate office no matter where he or she is in the world. Although mindful of the satellite link, this customer doesn’t really care how the telephone system works, as long as it is always available easily and reliably.
It has been consistently estimated that the total price for satellite service will be about $3.00 per minute. This price is about 25 percent to 35 percent higher than normal cellular roaming rates plus long distance charges. When using the roaming cellular capability, the price will be about $1.00 to $1.25 per minute.
The expected break-even market for Iridium is about 600,000 customers globally, assuming an undisclosed average usage per customer per month. The company hopes to recover its $5 billion investment within one year, or by the fourth quarter of 1999. Based on independent research, Iridium anticipates a customer base of 5 million by 2002.
PROBLEMS
As might be expected for a complex undertaking, the deployment of the constellation and the manufacture of the handsets has not been without glitches. So far, a total of nine spacecraft have suffered in-orbit failures. In addition, Iridium has announced delays in the development of the handset software.
Of the 72 satellites launched, including spares, one lost its stationkeeping fuel when a thruster did not shut off, one was damaged as it was released from a Delta II launch vehicle, and three had reaction wheel problems. In July two more satellites failed because of hardware problems. Delta II and Long March rockets, scheduled to begin a maintenance program of launching additional spares, were retargeted to deploy nine replacement birds to the orbital planes where they are needed in August.
Investors are also nervous about final software upgrades to the handsets. Following alpha trials last month, beta testing of the units was scheduled to commence within one week of the September 23 commercial activation date. The Motorola handsets are expected to be available to meet initial demand, but those made by Kyocera may not be ready until later. [Note added: On September 9, Iridium announced that the debut of full commercial service would be delayed until November 1 because more time is needed to test the global system.]
The fifteen gateways have been completed. Equipment for the China gateway, the last one, was shipped recently. Like a theatrical production, the players are frantically completing last minute details as the curtain is about to go up and Iridium embarks upon the world stage.
THE FUTURE
Iridium is already at work on its Next Generation system (Inx). Planning the system has been underway for more than a year. Although details have not been announced, it has been suggested that the system would be capable of providing broadband services to mobile terminals. In part, it would augment the fixed terminal services offered by Teledesic, which Motorola is helping to build, and might include aspects of Motorola’s former Celestri system. It has also been reported that the Inx terminal would provide greater flexibility in transitioning between satellite and cellular services and that the satellite power level would be substantially increased.
As customers sign up for satellite mobile telephony service, the utility and competitive advantage will become apparent. Information will flow more freely, the world will grow still smaller, and economies around the world will be stimulated. There will also be a profound effect on geopolitics and culture. Just as satellite television helped bring down the Berlin Wall by the flow of pictures and information across international boundaries, the dawning age of global personal communication among individuals will bring the world community closer together as a single family.
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Dr. Robert A. Nelson, P.E. is president of Satellite Engineering Research Corporation, a satellite engineering consulting firm in Bethesda, Maryland, a Lecturer in the Department of Aerospace Engineering at the University of Maryland and Technical Editor of Via Satellite magazine.
How to Promote Your ATI Course in Social Media
LinkedIn for ATI Rocket Scientists
Did you know that for 52% of professionals and executives, their LinkedIn profile is the #1 or #2 search result when someone searches on their name?
For ATI instructors, that number is substantially lower – just 17%. One reason is that about 25% of ATI instructors do not have a LinkedIn profile. Others have done so little with their profile that it isn’t included in the first page of search results.
If you are not using your LinkedIn profile, you are missing a huge opportunity. When people google you, your LinkedIn profile is likely the first place they go to learn about you. You have little control over what other information might be available on the web about you. But you have complete control over your LinkedIn profile. You can use your profile to tell your story – to give people the exact information you want them to have about your expertise and accomplishments.
Why not take advantage of that to promote your company, your services, and your course?
Here are some simple ways to promote your course using LinkedIn…
On Your LinkedIn Profile
Let’s start by talking about how to include your course on your LinkedIn profile so it is visible anytime someone googles you or visits your profile.
1. Add your role as an instructor.
Let people know that this course is one of the ways you share your knowledge. You can include your role as an instructor in several places on your profile:
3. Upload course materials.
You can upload course materials to help people better understand the content you cover. You could include PowerPoint presentations (from this course or other training), course handouts (PDFs), videos or graphics. They can be added to your Summary, Experience or Project. You can see an example of an upload above, in Tom Logsdon’s profile.
4. Add skills related to your course.
LinkedIn allows you to include up to 50 skills on your profile. If your current list of skills doesn’t include the topics you cover in your course, you might want to add them.
Go to the Skills & Endorsements section on your Edit Profile page, then click on Add skill. Start typing and let LinkedIn auto-complete your topic. If your exact topic isn’t included in the suggestions, you can add it.
5. Ask students for recommendations.
Are you still in touch with former students who were particularly appreciative of the training you provided in your course? You might want to ask them for a recommendation that you can include on your profile. Here are some tips on 
The Soyuz TMA-06M spacecraft docked at the space station’s rooftop after a two-day orbital chase. Riding on the Soyuz were American astronaut Kevin Ford of NASA and Russian cosmonauts Oleg Novitskiy and Evgeny Tarelkin, who are beginning a five-month mission to the space station.
“We can see you, everything looks fine,” Russian cosmonaut Yuri Malenchenko, who was already onboard the station, told the approaching crew before the two spacecraft docked about 230 miles (370 km) over southern Ukraine.
Ford, Novitskiy and Tarelkin launched into space on Tuesday (Oct. 23) atop a Soyuz rocket that blasted off from the Central Asian spaceport of Baikonur Cosmodrome in Kazakhstan. They are the second half of the space station’s six-person Expedition 33 crew, which is commanded by NASA astronaut Sunita Williams. Malenchenko and Japanese astronaut Akihiko Hoshide round out the crew.
The Soyuz spacecraft is bringing some fishy friends to the space station in addition to its human crew. The spacecraft is ferrying 32 small medaka fish to the space station so they can be placed inside a tank, called the Aquatic Habitat, for an experiment to study how fish adapt to weightlessness.
Thursday’s Soyuz docking at the space station kicks off a flurry of arrivals and departures at the International Space Station.
A robotic Dragon space capsule built by the private spaceflight company SpaceX will depart the space station on Sunday (Oct. 28) and splash down in the Pacific Ocean off the coast of Southern California. The Dragon capsule will return nearly 2,000 pounds (907 kilograms) of science experiment hardware and other gear back to Earth.
On Wednesday (Oct. 31), an unmanned Russian Progress spacecraft will launch toward the space station and arrive six hours later to make a Halloween delivery of food, equipment and other Halloween treats.
Williams, Hoshide and Malenchenko are in the final weeks of their mission to the space station, and will return to Earth Nov. 12. At that time, Ford will take command of the space station crew to begin the Expedition 34 mission.
The Boeing Company 
