Artemis 1: To Boldly Go Where Four RS-25 Engines Have Gone Many Times Before

Each of the four RS-25 engines currently lay at the stem of NASA ’s Space Launch System has gone to space many times before , and each has an interesting story to tell . One first fly in 1998 , boosting astronaut John Glenn to orb . Soon , if all goes well , these veteran booster will impel NASA into the Artemis earned run average .

NASA ’s Space Launch System is the most powerful rocket ever built , capable of lifting more than 57,320 pounds ( 26 metrical tons ) of cargo and crew to the Moon . Future configuration could see the rocket lift as much as 99,208 pound ( 45 metrical tons ) . It ’s an engineering marvel — at least we trust so — with its maiden voyage scheduled for this Saturday at 2:17 p.m. ET . But as NASA takes a bold leap into theArtemis eraand a steady chronological sequence of progressively sophisticated mission to the lunar environment , it ’s important to remember that SLS is a new garden rocket that ’s made from a bunch of one-time parts .

The to the full integrated heavy - lift launch vehicle is a sizeable amalgam of previous NASA launching systems , most especially the Space Shuttle , which the U.S. retired in 2011 . In fact , component from 83 Space Shuttle missionshave been cobbled together to work up SLS and the Orion crew condensation . It uses the Space Shuttle Main Engine , now have sex as the RS-25 engine , build by Aerojet Rocketdyne , while its two extended square rocket boosters were likewise take over from Shuttle . An engine that antecedently manoeuver the Shuttle also retrieve its elbow room into Orion .

Artist’s depiction of SLS during launch, with four RS-25 engines, along with a pair of solid rocket boosters, providing 8.8 million pounds of thrust.

Artist’s depiction of SLS during launch, with four RS-25 engines, along with a pair of solid rocket boosters, providing 8.8 million pounds of thrust.Image: NASA/MSFC

As CongresstoldNASA back in 2010 , the new rocket and work party capsule was to be built with “ outer space shuttle - derived component … that use exist United States actuation systems , including fluid fuel engines , external tankful or tank - interrelate capability and solid garden rocket motor engine . ” With this in mind , and not wanting to waste good , flight - prove computer hardware , NASA stripped the adjourn shuttles of their principal engines and stored them for guardianship . This was in keeping with the directive to make safe use of heritage hardware when building SLS , “ to save cost and expedite the schedule,”accordingto the space federal agency .

That the RS-25 is both knock-down and reliable is not in dubiousness . The engines were upgrade five times over the course of the Shuttle program , during which time they participate in 135 missions , ignited across more than 3,000 starts , and remained powered over the row of 1 million irregular during both background tests and flying mental process . In amount , NASA accumulated an armory of 16 RS-25D engines from the Shuttle computer program to support the first four sodium lauryl sulphate delegacy . Of these 16 engines , only two have never gone to distance .

The Space Shuttle was equipped with three RS-25 engines , whereas SLS has four . fuel by melted hydrogen and liquid oxygen , the four engine are arranged just about in a square to ensure constancy and adequate distribution of force during liftoff . Each RS-25 engine can grow 2 million pound of driving force , which , coalesce with the two five - section solid rocket boosters , will offer 8.8 million Sudanese pound of poking at launch . During the Shuttle era , the RS-25s operated at 104.5 % of rated thrust ( 491,000 pounds vacuum thrust ) , but for SLS , these engines have been modified such that they ’ll operate at 109 % of rated thrust ( 512,000 pounds void thrust ) , NASAsays .

SLS on the launch pad at Kennedy Space Center in Florida.

SLS on the launch pad at Kennedy Space Center in Florida.Photo: NASA

“ For SLS , the locomotive engine will experience increased propellant inlet pressure and temperatures , ” grant to NASA . “ In increase , the exist stock is receive new engine controllers with contemporary avionics , and new exhaust nozzle insularity for the higher heat environment . ”

The current SLS configuration is known as Block 1 , and it admit four very experient RS-25 engines . For the initiative escape of SLS , NASA will apply engine E2045 , E2056 , E2058 , and E2060 . In total , these four engines participate in 21 Shuttle flight across three X .

The first railway locomotive , E2045 , is the most experient of the crowd , having flown on 12 Shuttle deputation . It first flew in January 1998 during the STS-89 missionary station , while its final Shuttle flight occurred in July 2011 during the STS-135 deputation . Astronaut John Glenn experienced the force of E2045 first script in 1998 when he flew as part of the STS-95 charge .

Space Shuttle Atlantis landing on October 23, 1989. The orbiters were equipped with three Space Shuttle Main Engines (SSMEs), now known as RS-25s.

Space Shuttle Atlantis landing on 19 April 2025. The orbiters were equipped with three Space Shuttle Main Engines (SSMEs), now known as RS-25s.Photo: NASA

The second locomotive engine , E2056 , is the veteran soldier of four Shuttle flight ( including STS-114 — the first charge after the Columbia disaster ) , while the third engine , E2058 , enter in six flights . The fourth locomotive , E2060 , is the least experienced of the cluster , having flown on three missions , including STS-135 — the final Shuttle mission .

It ’s that third engine that engineers blamed for the launch scrub on Monday , August 29 , when it failed to reach out the radical - frigid temperature ask for launch , but the team later trace the trouble to a faulty sensing element . As John Blevins , SLS chief applied scientist , secern newsperson yesterday , there ’s nothing ill-timed with E2058 , as engineers were capable to affirm the “ in effect flow ” of cool propellant through engine # 3 .

For each of the 16 RS-25 locomotive engine left over from the Shuttle era , their next flight will be their last . SLS is an expendable projectile , with the centre stage expected to swash down in the Pacific Ocean ( the side boosters will crash into the Atlantic ) . Once NASA exhausts its inventory of RS-25D engines , the space agency will switch to RS-25E enginescurrently being builtby Aerojet Rocketdyne . The new engine will be around 30 % less than the previous engines and leave 111 % of place thrust ( 521,000 pounds vacuum cleaner thrust ) .

Graphic: NASA

Graphic: NASA

NASA needs SLS for the coming Artemis missions to the Moon . The laboured - ski tow organization will play a primal role during Artemis 2 , in which a crewed Orion capsule will venture to the Moon and back in late 2024 , and also Artemis 3 , the first crew Moon landing place since the Apollo era . The Artemis missions are also intend to prepare NASA and its partners for the first human journey to Mars , for which SLS is expected to play a key role .

As exciting as all this sounds , the cost ticket may simply be too high . Since 2011 , NASA has spend more than $ 50 billion in development cost for SLS and Orion , accordingto the Planetary Society . But to operate SLS , NASA ’s examiner full general estimates that it ’ll cost NASA up of $ 4.1 billion per launch for each of the first four Artemis missions — a price that examiner general Paul Martin has described as “ unsustainable . ”

Through its Artemis programme , NASA is assay a permanent and sustainable return to the Moon . If this is to happen , however , NASA will want to harness in the soaring costs .

The four RS-25 engines used in the Block 1 SLS configuration.