The four Aerojet Rocketdyne RS-25 engines powering the SLS core stage can provide over 500,000 pounds of thrust. Like Artemis I, the next three SLS flights will use refurbished Space Shuttle Main Engines equipped with state-of-the-art flight controllers. However, the RS-25 engines that will power future missions have been completely rethought to increase efficiency while decreasing costs. The RS-25 is the only high-performance engine in use today that uses liquid hydrogen in a staged combustion cycle.
On the historic Fred Haise Test Stand at NASA’s Stennis Space Center, engineers conducted a series of tests from February 8th through June 22nd, with firings lasting anything from 500 seconds (consistent with the normal SLS flight profile) to 720 seconds.
About Aerojet Rocketdyne
Aerojet Rocketdyne is an American company that makes rockets, hypersonic vehicles, and electric propulsion systems for use in military, commercial, and civilian settings. Aerojet Rocketdyne Holdings is the parent firm of the Sacramento, California-based corporation. In 2013, GenCorp, which already owned Aerojet, amalgamated with Pratt & Whitney Rocketdyne, which GenCorp had just acquired from Pratt & Whitney, to establish Aerojet Rocketdyne. The parent firm GenCorp changed its name to Aerojet Rocketdyne Holdings, Inc. on April 27, 2015.
Aerojet Rocketdyne Marks Milestone
From 80% to 111% rated power, and even briefly at 113% rated power to show operating safety margin, the engine was put through its paces during the test series.
Engine gimbaling at off-center angles of 1 to 6 degrees were also shown during the certification campaign, as were the new optimized flexible fuel and oxidizer feed lines that lead to cheaper hardware. The gimbal demonstrations and extended testing are useful for expanding the RS-25 performance database and apply to certain flying conditions.
Four of mighty engines, each capable of producing over 500,000 pounds of thrust, propel the SLS core stage. The three planned SLS missions, like Artemis I, will use retrofitted Space Shuttle Main Engines. However, the freshly constructed RS-25 engines will be used on subsequent flights. The RS-25 is the first engine in the world that use a staged combustion cycle and run on liquid hydrogen for high performance.
From February 8 through June 22, 2023, a series of certification tests were performed at NASA’s Stennis Space Center on the legendary Fred Haise Test Stand. Some firings lasted as little as 500 seconds, in line with the standard SLS flight profile, to as long as 720 seconds. The engine was put through its paces from 80% to 111% of its rated power, and even 113% for a short period of time, exhibiting what Aerojet called “a valuable operational safety margin.”
In order to finish the certification procedure, NASA and Aerojet Rocketdyne will undertake a similar 12-test series on a separate engine later this summer. The brand-new engines will make their first appearance on NASA’s Artemis V mission, which is set to launch in 2024.
The successful conclusion of this 12-test campaign is a significant achievement in our efforts to resume RS-25 manufacturing. Our faith in the new hardware designs and production methods that were put to the test in this set of tests has been restored. Aerojet Rocketdyne’s President and Chief Executive Officer Eileen P. Drake.
