Northrop Grumman Corporation has developed and successfully tested a Reaction Control Subsystem (RCS) engine for next-generation reusable space launch and transportation vehicles. The new engine burns nontoxic propellants, an achievement that enhances safety, reliability and affordability.
Developed by the company's Space Technology sector under a contract awarded in 2001 for NASA's Next Generation Launch Technology program, the RCS Thruster is made of a pure alloy - platinum iridium - and burns a combination of liquid oxygen and ethanol. These two developments eliminate the need for a ceramic coating currently used to protect RCS engines from damage caused by historically used toxic propellants.
RCS engines on Space Shuttle orbiters have been replaced as a result of service, handling or foreign object damage to such coatings, which are only three to six thousandths of an inch thick. In addition, workers need to take stringent, time-consuming safety precautions when maintaining or repairing hardware that currently uses toxic propellants.
"Our RCS Thruster increases the reliability, maintainability and safety of space vehicle engines," said Sonya Sepahban, vice president and deputy of technology development for Northrop Grumman Space Technology. "We began developing this 'clean propellant' engine more than two years ago. It's the first uncoated RCS engine developed and tested in the United States for NASA. We believe this engine will greatly increase both vehicles' utility and reusability."
The test, conducted at the company's Capistrano Test Site in San Clemente, Calif., demonstrated pulsing capability and steady state firing capability, showing that the engine exceeds performance requirements.
"Though we're still in the early stages of development, the platinum iridium chamber has proven very robust by handling the optimum mixture ratio with comfortable temperature margins," said Bernard Jackson, Space Technology project manager.
The RCS Thruster engine is based on Northrop Grumman Space Technology's pintle injector concept and shares heritage with the company's reliable Lunar Module Descent Engine and the 100-pound thrust engine used to insert NASA's Chandra X-ray Observatory into a highly elliptical orbit.