Category Archives: Satellites

NASA FY 2011 Budget Data Available

NASA FY 2011 Budget Data are posted online at:

Also see previous posts below New Direction Planned for Space Exploration.

WASHINGTON — NASA’s Fiscal Year 2011 Budget Estimates on Monday, providing more information about the president’s plan for the agency’s future. The material highlights spending plans for program elements for each of the agency’s mission directorates, further defining the budget request unveiled Feb. 1. The information provides significant additional detail on the new programs, their goals, and the rationales for NASA’s new direction in human space exploration.

The 2011 budget proposal supports bold and ambitious space initiatives that invest in American ingenuity, develop more innovative technologies, foster new industries, strengthen international partnerships, and increase our understanding of the Earth, our solar system, and the universe beyond — all to propel the agency on a new journey of innovation and discovery.

NASA Data for Climate Warming Says Warming Continues for Decade Ending 2009

Global warning continues to make the news. Do you think
1. Global warming is proven?
2. Are the costs associated with Cap and Trade reasonable?

NASA WASHINGTON — A new analysis of global surface temperatures by NASA scientists finds the past year was tied for the second warmest since 1880. In the Southern Hemisphere, 2009 was the warmest year on record.

Although 2008 was the coolest year of the decade because of a strong La Nina that cooled the tropical Pacific Ocean, 2009 saw a return to a near-record global temperatures as the La Nina diminished, according to the new analysis by NASA’s Goddard Institute for Space Studies (GISS) in New York. The past year was a small fraction of a degree cooler than 2005, the warmest on record, putting 2009 in a virtual tie with a cluster of other years –1998, 2002, 2003, 2006, and 2007 — for the second warmest on record.

“There’s always interest in the annual temperature numbers and a given year’s ranking, but the ranking often misses the point,” said James Hansen, GISS director. “There’s substantial year-to-year variability of global temperature caused by the tropical El Nino-La Nina cycle.
When we average temperature over five or ten years to minimize that variability, we find global warming is continuing unabated.”

January 2000 to December 2009 was the warmest decade on record.
Looking back to 1880, when modern scientific instrumentation became available to monitor temperatures precisely, a clear warming trend is present, although there was a leveling off between the 1940s and 1970s.

In the past three decades, the GISS surface temperature record shows an upward trend of about 0.36 degrees F (0.2 degrees C) per decade.
In total, average global temperatures have increased by about 1.5 degrees F (0.8 degrees C) since 1880.

“That’s the important number to keep in mind,” said GISS climatologist Gavin Schmidt. “The difference between the second and sixth warmest years is trivial because the known uncertainty in the temperature measurement is larger than some of the differences between the warmest years.”

GEO Satellite question

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.