Aerojet Rocketdyne successfully completed the first in a series of hot-fire tests on the RS-25 engine, which will be used on NASA’s Space Launch System (SLS), according to a company statement.
The company said the test, conducted at NASA’s Stennis Space Center, Miss., demonstrated the ability of the engine’s new computer to control the engine, from fuel-mixture ratios to power levels and performance. The RS-25 is formerly known as the Space Shuttle Main Engine (SSME). The controller on the SSME served as the “brain” and was manufactured in the 1980s, allowing for communication between the vehicle and the engine.
The new computer has since been modernized with the latest technologies to provide the capability necessary for four RS-25 engines to power the SLS core stage. During the first hot-fire test at Stennis, NASA and Aerojet Rocketdyne engineers tested the upgraded engine controller’s ability to control the engine, using different power levels and inlet conditions, according to NASA.
The RS-25 fired for roughly eight minutes, 20 seconds on Jan. 9 in the first hot-fire test of a RS-25 engine since the end of space shuttle main engine testing in 2009, NASA said. The modifications to the RS-25 will meet SLS specifications, according to a NASA engineer.
“The engines for SLS will encounter colder liquid oxygen temperatures than shuttle and greater inlet pressure due to the taller core stage liquid oxygen tank and higher vehicle acceleration,” Steve Wofford, manager of the SLS liquid engines office at NASA’s Marshall Space Flight Center, Ala., said in a statement. “(It will also encounter) more nozzle heating due to the four-engine configuration and their position in-plane with the SLS booster exhaust nozzles.”
Testing will resume in April after upgrades are completed on the high-pressure industrial water system, which provides cool water for the test facility during a hot-fire test. Eight tests; totaling 58 minutes, 20 seconds; are planned for the current development engine. Another development engine will later undergo 10 tests, totaling 75 minutes of testing. The second test series includes the first test of new flight controllers, known as green running.
The first unscheduled flight test of SLS will feature a configuration for a 77-ton lift capacity and carry an uncrewed Orion spacecraft beyond low-earth orbit to test the performance of the integrated system.
Aerojet Rocketdyne is a division of GenCorp [GY].