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SLS (Space Launch System) Interim Cryogenic Propulsion Stage

The SLS (Space Launch System) interim cryogenic propulsion stage (ICPS) is an in-space rocket stage that provides propulsion to the Orion spacecraft during the first three Artemis missions.

Encyclopedia
Updated Nov 29, 2024

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The SLS (Space Launch System) interim cryogenic propulsion stage (ICPS) is an in-space rocket stage that provides propulsion to the Orion spacecraft during the first three Artemis missions.

Measuring 45 ft. (13.7 m) tall and 16.7 ft. (5.1 m) in diameter, the ICPS provides in-space propulsion after the SLS solid rocket boosters and core stage are jettisoned. This propulsion is provided by the RL10 engine, which uses a liquid hydrogen/liquid oxygen-based system.

During the successful Artemis I uncrewed test mission, the ICPS’s RL10 engine provided the Orion spacecraft the final boost it needed to flyto the Moon with extreme precision, burning for a record-breaking 18 minutes.

These images and videos show how crews in Alabama prepared the ICPS (interim cryogenic propulsion stage) for NASA’s SLS (Space Launch System) rocket for shipment to Florida between July 29-31. The ICPS in the photos and videos will help power NASA’s Artemis III mission to the Moon. The SLS upper stage is manufactured by United Launch Alliance at its facility in Decatur. Its RL10 engine is produced by Aerojet Rocketdyne, the SLS engines lead contractor, in West Palm Beach, Florida. ULA is working with Boeing, the SLS core stage and exploration upper stage lead contractor, to develop ICPS. ULA’s R/S RocketShip is transporting the flight hardware to its sister facility in Florida near NASA’s Kennedy Space Center for final checkouts. The ICPS for Artemis III is the last of its kind as SLS transitions to its next, more powerful Block 1B configuration with an upgraded upper stage beginning with Artemis IV. NASA is working to land the first woman and first person of color on the Moon under Artemis. SLS is part of NASA’s backbone for deep space exploration, along with Orion and the Gateway in orbit around the Moon. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single mission.
The interim cryogenic propulsion stage (ICPS), a modified United Launch Alliance Delta Cryogenic Second Stage, provides 24,750 lbs. of thrust for in-space propulsion for the Block 1 crew and cargo vehicles.
NASA/Brandon Hancock

During Artemis II, Orion and ICPS will orbit Earth twice, with the ICPS firing once to maintain Orion’s path and firing a second time to raise the spacecraft to a high-Earth orbit.

After the Orion spacecraft separates from the SLS upper stage, Artemis II astronauts will use a target affixed on the outside of the ICPS as a visual marker to “test drive” Orion. This demonstration will assess Orion’s handling qualities for future rendezvous and docking operations with other Artemis components such as human landing systems and the Gateway lunar space station.

Approximately two hours after the Artemis I launch on Nov. 16, 2022, the ICPS separated from Orion after completing the translunar injection burn that put the spacecraft on course toward the Moon.
Approximately two hours after the Artemis I launch on Nov. 16, 2022, the ICPS separated from Orion after completing the translunar injection burn that put the spacecraft on course toward the Moon.
NASA
Expanded illustration of SLS (Space Launch System) Block 1.

Built by Boeing and United Launch Alliance, the ICPS is a modified Delta Cryogenic Second Stage, a proven upper stage used on United Launch Alliance’s Delta IV family of launch vehicles.

Modifications for SLS include lengthening the liquid hydrogen tank, adding hydrazine bottles for attitude control, minor avionics changes, and a modified liquid hydrogen vent and relief valve that supports RL10 in-flight engine restart.

The propulsion system is managed under the SLS Program by the Spacecraft/Payload Integration and Evolution Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.

NASA is working to land the first woman, first person of color, and its first international partner astronaut on the Moon under Artemis. SLS is the only rocket that can send Orion, astronauts, and supplies to the Moon in a single launch.

Interim Cryogenic Propulsion Stage Details

Height……………………. 43 ft. (13 m)

Diameter………………….17 ft. (5 m)

Propellant………………. Liquid Hydrogen/Liquid Oxygen

Engine……………………. 1 Aerojet Rocketdyne, a L3Harris Technologies Company, RL10

Thrust……………………..24,750 lbs

Contractors……………..Boeing, United Launch Alliance

National Aeronautics and Space Administration

George C. Marshall Space Flight Center
Huntsville, AL 35812
www.nasa.gov/marshall

www.nasa.gov

For more information about SLS, visit:
http://www.nasa.gov/artemis
http://www.nasa.gov/sls
http://www.twitter.com/NASA_SLS
http://www.facebook.com/NASASLS
http://www.instagram.com/nasaartemis

MSFS-11-2024-SLS-4980