Liquid Rocket Engines for Spacecraft Pressure-Fed Propulsion Systems

Course Length:



Liquid Rocket Engines have been used to propel Earth orbiting satellites and deep space interplanetary missions for the last five decades.
This three-day course provides in-depth treatment of the fundamental concepts and technologies of modern spacecraft liquid propellant rocket engines. The course focuses on scientific and engineering foundations of pressure- fed, monopropellant, bipropellant, dual mode, and secondary combustion augmented thrusters for satellite orbit-raising and station-keeping operations. Thruster analyses; design; ground testing; flight operations; and lessons learned will be discussed in detail. Interactions of thrusters with the propulsion subsystem, and interfaces of the propulsion subsystem with other subsystems of spacecraft as they relate to the spacecraft overall design and operations will be discussed. The extensive set of course notes provides a concise reference for understanding virtually all aspects of modern spacecraft liquid thruster technologies. Each student will receive a copy of complete set of lecture notes and the relevant AIAA papers by the instructor and other authors.

What you will learn:

  • Fundamentals of
    • Rocket Propulsion and Rocket Engines
    • Flow-Pressure drop of liquids and gases in thruster valves and injector orifices
    • Heat transfer in thrusters
  • Developing thruster specification requirements
  • Thruster Design and Analysis
  • Developing thruster ground hot-fire test matrix
  • Thruster hot-fire testing
  • Thruster test data analysis
  • Thruster flight and in-orbit operations
  • Thruster EOL operation for optimum propellant life technical issues involved in the successful planning, design, development, fabrication, deployment and operation of space systems

Course Outline:

  1. Introduction: Course Overview: History of liquid rocket engines; Evolution of liquid propellant rocket engines from Second World War
  2. Rocket Engine Fundamentals and Definitions: Thrust, Impulse, Specific impulse, Impulse-bit, Thrust coefficient, Characteristic exhaust velocity, Catalytic decomposition, Combustion stoichiometry, Mixture ratio, Adiabatic flame temperature
  3. Monopropellant Rocket Engines: Hydrogen peroxide (H2O2) thrusters, Hydrazine (N2H4) thrusters, Catalytic decomposition reactions, Catalyst degradation mechanisms (catalyst bed voids, Catalyst bed poisoning)
  4. Early Bipropellant Rocket Engines: Early N2H4 / Nitric acid and Aerozine-50 / NTO bipropellant thrusters
  5. Current Bipropellant Rocket Engines: Disilicide-coated Columbium and Ir/Re chamber, hypergolic MMH/NTO orbit raising thrusters (100-lbf to 900-lbf class) and orbit maintenance thrusters (2-lbf to 25-lbf class)
  6. Future Dual Mode Rocket Engines: Disilicide-coated Columbium and Ir/Re chamber, hypergolic N2H4/NTO orbit raising thrusters (100-lbf class) and Platinum chamber orbit maintenance thrusters (5-lbf class)
  7. Secondary Combustion Augmented N2H4/NTO Thruster (SCAT): Nickel chamber, ability to operate in both mono- and bipropellant modes
  8. Bipropellant / Dual Mode Thruster Valves: Solenoid and Torque motor valves; Pressure actuated valves, Arc Suppressors, Valve testing (open/close response time; actuation cycles; flow-pressure drop, back-pressure relief feature, leakage, power, pull-in and drop-out voltage
  9. Bipropellant / Dual Mode Thruster Injectors: Showerhead, Platelet and Pintle injectors, Radiatively- and Regeneratively cooled injectors, Injectors for fuel film cooled (FFC) chambers), Rupe number, D/V “contact” time, Injector core momentum angle, oxidizer versus fuel lead Hydraulic Flip Injector coupling to combustion chamber and its effects on dribble volume and post-firing thermal soakback, Oxidizer Boiling, FORP ZOT, Thermal stresses, Deposits, Injector water-flow testing for stream quality and pressure drop
  10. Bipropellant/ Dual Mode Thruster Combustion Chamber Chamber materials and coatings, Chamber l/d ratio, Combustion instability, Thrust chamber burn-thru
  11. Nozzles: Straight conical and bell-shaped nozzle configurations
  12. Thruster Analyses: Steady state and pulse-mode performance, Startup & shutdown transients, Tail-off impulse, Thruster thermal analyses, Oxidizer boiling in injector orifices, Post-firing thermal soakback
  13. Thruster Ground Hot-Fire Testing: Test cell vacuum (vacuum pumps versus steam jet ejectors), Vertical versus Horizontal (nozzle-down) firing, Propellant saturation techniques, propellant temperature conditioning techniques, thrust measurement system, Pulse-mode flow measurement techniques, Oxidizer/fuel biasing, Propellant, valve and injector temperatures, Chamber temperature measurement, single species depletion, Data acquisition system (instrumentation response and data sampling rate), Propellant feed system flow-?P, Propellant feed system coupling, Developing test matrix, Test facility error analysis
  14. Spacecraft Flight Operations: Propulsion flight telemetry Propellant tank/ feed line pressures and temperatures, Valve and injector temperatures, Spacecraft dynamics parameters, Water hammer upon thruster valve closure, Single propellant species operation, Spacecraft end-of-life (EOL) de-orbit strategies


REGISTRATION:  There is no obligation or payment required to enter the Registration for an actively scheduled course.   We understand that you may need approvals but please register as early as possible or contact us so we know of your interest in this course offering.

SCHEDULING:  If this course is not on the current schedule of open enrollment courses and you are interested in attending this or another course as an open enrollment, please contact us at (410)956-8805 or Please indicate the course name, number of students who wish to participate. and a preferred time frame. ATI typically schedules open enrollment courses with a 3-5 month lead-time.   To express your interest in an open enrollment course not on our current schedule, please email us at

For on-site pricing, you can use the request an on-site quote form, call us at (410)956-8805, or email us at


  • G. P. Purohit, a retired Boeing Technical Fellow, is a recognized industry expert in Spacecraft Propulsion. He has worked virtually all aspects of spacecraft liquid propulsion systems and components for the past 35 years at JPL and at Boeing. He has published extensively on spacecraft propulsion. He received his MS and PhD in Mechanical Engineering from University of California, Los Angeles (UCLA). Dr. Purohit teaches graduate courses at USC on Spacecraft Propulsion and Satellite Thermal Control. He also teaches short courses on Propulsion at AIAA and UCLA where he has been cited as the Best Instructor. Dr. Purohit has served as Chair, ASME Liquid Propulsion Technical Committee, and as Technical Programs Vice Chair., AIAA Los Angeles Section. Dr. Purohit is the recipient of The AIAA Wyld Propulsion Award, NASA Exceptional Achievement Award, The US Government Eagle Award, and Boeing Technical Excellence Award

    Contact this instructor (please mention course name in the subject line)

Request On-Site Quote