The
Rocket

Space launch system: PUTTING IT ALL TOGETHER

NASA’s Space Launch System (SLS) is the backbone of a sustainable deep space exploration program that will yield breakthrough discoveries for years to come.

It cements U.S. leadership in space while engaging global partners aspiring to contribute to a sustained presence on and around the Moon and ultimately Mars.

Rocket image showing the components that make up the SLS.

Meet
the
Rocket

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MORE ABOUT THE DIFFERENT
COMPONENTS THAT FORM SLS

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MORE ABOUT THE DIFFERENT
COMPONENTS THAT FORM SLS

Orion Spacecraft

Built by Lockheed Martin

Launched on SLS, the Orion spacecraft will serve as the exploration vehicle that will carry up to four crew members to space, provide emergency abort capability, sustain the crew during multiweek missions and provide a safe reentry to Earth from deep space return velocities. It’s composed of a crew module, service module and launch abort system.

NASA photo

ICPS

Built by United Launch Alliance and Boeing

The Interim Cryogenic Propulsion Stage (ICPS) for SLS Block 1 is the initial configuration that can deliver 59,500 pounds (27 metric tons) of payload to the Moon. Based on the proven Delta Cryogenic Second Stage and powered by one Aerojet Rocketdyne RL10 engine, ICPS will propel an uncrewed Orion spacecraft to fly beyond the Moon and back on the Artemis I mission.

NASA photo

LVSA

Built by Teledyne Brown

The Launch Vehicle Stage Adapter (LVSA) connects the initial version of the core stage to the upper stage while providing structural, electrical and communication paths. It separates the core stage from the second stage that includes astronauts in the Orion crew vehicle. The cone-shaped adapter is roughly 30 feet (9.1 meters) in diameter by 30 feet tall. The LVSA consists of 16 aluminum-lithium 2195 alloy panels.

NASA photo

Avionics

Built by Boeing

Avionics are aerospace electronics, including the flight computers, power distribution, camera equipment, gyros and other devices housed in the SLS core stage forward skirt, intertank and engine section. They process data and give commands to guide the rocket’s trajectory while communicating with Orion, with one another and with ground control teams.

NASA photo

Forward Skirt

Built by Boeing

As the brains of SLS, the forward skirt is responsible for the rocket reaching its destination. It houses flight computers, cameras and avionics — the routers, processors, power, other boxes and software that control stage functions and communications. Along with the liquid oxygen tank and the intertank, it makes up the top half of the core stage.

NASA photo

LOX Tank

Built by Boeing

The liquid oxygen (LOX) tank holds 196,000 gallons (742,000 liters) of LOX cooled to minus 297 degrees Fahrenheit (minus 183.8 degrees Celsius). Its thermal foam coating protects it from extreme temperatures — the cold of the propellants and the heat of friction. A test article at NASA’s Marshall Space Flight Center in Alabama in 2020 was subjected to 170% maximum predicted flight loads — far beyond the pressures of liftoff and launch — before rupturing and spilling 197,000 gallons (746,000 liters) of water across the test stand.

NASA photo

Intertank

Built by Boeing

Joining the liquid hydrogen and liquid oxygen (LOX) tanks, the intertank houses avionics and electronics that will control the rocket in flight. It also anchors two massive solid rocket boosters. The avionics units on the SLS core stage work with the flight software to perform various functions during the first eight minutes of flight. Some control the navigation, some communicate with the Orion spacecraft, and some control how the engines perform. The intertank makes up the top half of the core stage, along with the LOX tank and forward skirt.

NASA photo

Core Stage

Built by Boeing

The aluminum 2219 alloy core stage supports the thrust from the engines beneath, the tug of the boosters, and the weight of the Orion spacecraft and other payloads. It is 212 feet (64.6 meters) tall, 188,000 pounds (85,300 kilograms) empty and 2.3 million pounds (1 million kilograms) fully fueled. Designed by Boeing engineers in Alabama, built in Louisiana and tested in Mississippi, it will launch from Kennedy Space Center in Florida.

NASA photo

LH2 Tank

Built by Boeing

The liquid hydrogen (LH2) tank comprises two-thirds of the core stage, weighs 150,000 pounds (68,000 kilograms) and holds 537,000 gallons (2 million liters) of LH2 cooled to minus 423 degrees Fahrenheit (minus 253 degrees Celsius). Thermal foam keeps the LH2 at the right temperature and pressure. A test article, structurally identical to the flight hardware, at NASA’s Marshall Space Flight Center in Alabama in 2019 withstood more than 260% of expected flight loads for over five hours before buckling.

NASA photo

Solid Rocket Boosters

Built by Northrop Grumman

The largest human-rated solid rocket boosters ever built for flight, the SLS twin boosters stand 17 stories tall and burn 1.4 million pounds (628,000 kilograms) of propellant in two minutes. Each booster generates more thrust than 14 four-engine 747 airplanes. Together, the SLS twin boosters provide more than 75% of the total thrust at launch.

NASA photo

Engine Section

Built by Boeing

In addition to its miles of cabling and hundreds of sensors, the engine section is a crucial attachment point for the four RS-25 engines that work with two solid rocket boosters to produce a combined 8.8 million pounds (4 million kilograms) of thrust at liftoff. Avionics here steer the engines, too. It was built vertically and rotated to horizontal to connect with the liquid hydrogen tank.

NASA photo

RS-25 Engines

Built by Aerojet Rocketdyne

Four RS-25 engines will deliver more than 2 million pounds (907,000 kilograms) of thrust at altitude. Combined with two five-segment solid rocket boosters, the propulsion system will give SLS more lift than any current rocket and 15% more than the Saturn Vs that launched the Apollo missions. An RS-25 variant is in production for Artemis missions past the first four.

Aerojet Rocketdyne photo

Follow
the
Timeline

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MORE ABOUT THE PATH
TO LAUNCH

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TO LAUNCH

Artemis I Core Stage Rollout

January 2020

NASA declared the SLS core stage for Artemis I complete on Dec. 9, 2019, at the agency’s Michoud Assembly Facility. The New Orleans factory is where Boeing created a production system to build the SLS core and upper stages and avionics and to complete preliminary testing. After checkouts, employees escorted the first core stage to NASA’s Pegasus barge. It was the first time a completed rocket stage had shipped out of Michoud since the Apollo program.

NASA photo

Installation in Stennis Test Stand

January 2020

The Artemis I core stage traveled from NASA’s Michoud Assembly Facility in New Orleans to NASA’s Stennis Space Center in Bay St. Louis, Mississippi, for testing on the B-2 test stand used in the Apollo and shuttle eras. Boeing teams prepared the massive stand to receive the 212-foot (65-meter)-tall core stage, the largest NASA has ever built or tested. After days of careful handling, the core stage was safely lifted into the stand.

NASA photo

Green Run Tests Complete

March 2021

The Green Run test series for the core stage took place over the next year. “Green” refers to the new hardware and “run” refers to operating it all together. Engineers turned the components on one by one to assess the stage, then fully fueled it. Green Run culminated in an eight-minute firing of the four engines through a “launch” and “ascent” while the fully operational stage remained locked into the test stand.

NASA photo

Delivery to Kennedy Space Center

April 2021

Teams inspected and refurbished the core stage before removing it from the B-2 test stand at Stennis Space Center in Mississippi and preparing it for shipment to Kennedy Space Center in Florida. The stage traveled 900 miles (1,400 kilometers) on the NASA Pegasus barge, then was offloaded and rolled into the Vehicle Assembly Building. There, it was stacked on its mobile launcher between two solid rocket boosters.

NASA photo

SLS Stacking Complete

October 2021

A launch vehicle stage adapter, Interim Cryogenic Propulsion Stage and Orion spacecraft stage adapter were added to the top of the Artemis I SLS core stage in a series of lifts in the Vehicle Assembly Building.

Tests performed during stacking included release and retraction of the rocket’s “umbilical” connections to the mobile launcher. SLS also successfully completed its design certification review.

NASA photo

Orion Stacked on Artemis I SLS

October 2021

Crews added the Orion spacecraft and its launch abort system on top of the Orion stage adapter to complete the launch system for Artemis I. The uncrewed Orion will be launched by SLS and boosted on a trajectory to the Moon by the rocket’s Interim Cryogenic Propulsion Stage.

NASA photo

SLS Rollout

March 2022

Boeing and other industry partners supported NASA as it completed more tests of the Artemis I system in the Vehicle Assembly Building (VAB) and practiced launch and mission operations. On March 17, NASA rolled the entire rocket through the VAB’s 456-foot (139-meter) door for the first time for a nearly 11-hour trip to the launch pad to undergo its final prelaunch tests.

NASA photo

Wet Dress Rehearsal

June 2022

After SLS and its mobile launcher made the approximately 11-hour, 4-mile (6.4-kilometer) trip to launch pad 39B on a 6.6 million-pound (3 million-kilogram) crawler-transporter, the rocket completed a wet dress rehearsal. Teams loaded, controlled and drained cryogenic propellants from the rocket’s core and upper stages and practiced a launch countdown. They collected test data before returning the rocket to a safe condition for rolling it back to the VAB.

NASA photo

Launch

2022

After wet dress rehearsal, the next time SLS and Orion roll out will be for the Artemis I mission countdown and launch!

NASA photo