The new order, valued at $1.79 billion, calls for the California-based aerospace company Aerojet Rocketdyne to provide 18 RS-25 engines to power future SLS rockets. The agreement builds upon an existing deal between NASA and Aerojet for six SLS engines. This new order boosts the final contract's value to about $3.5 billion through 2029, NASA officials said.
"This contract allows NASA to work with Aerojet Rocketdyne to build the rocket engines needed for future missions," NASA SLS program manager John Honeycutt at the agency's Marshall Space Flight Center in Huntsville, Alabama said in a statement.
Each SLS rocket will use four RS-25 rocket engines to launch its 212-foot (65-meter) core stage. The rocket will also use two strap-on solid rocket boosters and an upper stage to launch NASA's Orion crew capsule. The Artemis program will use SLS and Orion to return astronauts to the moon by 2024.
NASA currently has 16 of the engines (salvaged from the agency's now-retired space shuttle program) that will be used on the first four SLS rocket launches for Artemis missions 1 through 4. Those engines will cover Artemis flights through the program's first crewed moon landing (Artemis 3) and a follow-up flight.
NASA's Artemis 1 mission is expected to launch in 2021. The engines for that flight are installed on an SLS core stage and awaiting a major test at NASA's Stennis Space Center in Mississippi. That work has been on hold since March due to the ongoing coronavirus pandemic.
The new agreement with Aerojet Rocketdyne will add another 24 SLS engines for the Artemis program, enough for another six flights.
"We've already begun production on the first six new RS-25 engines," SLS engines manager Johnny Heflin said in the same statement. "Aerojet Rocketdyne has restarted the production lines, established a supplier base and is building engines using advanced techniques that reduce both the cost and time for manufacturing each engine."
The SLS rocket's four RS-25 engines provide a total of 2 million lbs. of thrust during launch to carry an Orion capsule into orbit. The engines left over from the space shuttle program have been overhauled with new computer controllers and upgraded to ensure they can handle the higher performance demands of an SLS launch, NASA officials have said.
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