While much of the United States was bundled up against the biting cold, NASA was basking in the heat of rocket fuel burning during the first successful test of the Space Launch System (SLS) at the Stennis Space Center in Mississippi on Jan. 9.
Cradled on the A-1 test stand, the RS-25, which used to be the main shuttle engine, fired up for 500 seconds, according to NASA. Engineers were able to gather important data on the engine controller unit and inlet pressure conditions. The last hot fire of an RS-25 engine was in 2009.
NASA will use four RS-25 engines to power SLS on future missions, which will include a visit to an asteroid and the eagerly-awaited mission to Mars.
"We've made modifications to the RS-25 to meet SLS specifications and will analyze and test a variety of conditions during the hot fire series," said Steve Wofford, manager of the SLS Liquid Engines Office at NASA's Marshall Space Flight Center in Alabama. "The engines for SLS will encounter colder liquid oxygen temperatures than shuttle; greater inlet pressure due to the taller core stage liquid oxygen tank and higher vehicle acceleration; and more nozzle heating due to the four-engine configuration and their position in-plane with the SLS booster exhaust nozzles."
The engine controller unit acts as the engine's "brain," passing commands and data between the vehicle and the engine. The controller is also responsible for closed-loop management. The thrust and fuel mixture ratio must be monitored as well as engine health. The new, modified controller will bring the engine to SLS avionics operations level with new hardware and software, according to NASA.
"This first hot-fire test of the RS-25 engine represents a significant effort on behalf of Stennis Space Center's A-1 test team," said Ronald Rigney, RS-25 project manager at Stennis. "Our technicians and engineers have been working diligently to design, modify and activate an extremely complex and capable facility in support of RS-25 engine testing."
The next test is planned for April, which is the scheduled month of completion for updates on the high pressure industrial water system that furnishes cool water during a hot fire test.
Current engine development will involve eight tests, totaling 3,500 seconds. Another will complete 10 tests, totaling 4,500 seconds. The second will involve a preliminary test of new flight controllers, which is called "green running."
The first test flight of the SLS will carry an unmanned Orion spacecraft beyond low-Earth orbit with a configuration for a 77-ton lift capacity, according to NASA. Further upgrades will increase lift capacity to 143 tons, which will propel future deep space missions.
