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NASA Space Launch System (Artemis crew)

Boeing · Reusable Space Vehicle · USA · Digital Age (2010–present)

NASA Space Launch System (Artemis crew) — Reusable Space Vehicle
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The Space Launch System (SLS) is an American super-heavy-lift rocket built for NASA's Artemis Program. It is the most powerful launch vehicle flying today, taking that title back from the Saturn V after a 50-year gap. Boeing serves as prime contractor for the Core Stage, Northrop Grumman builds the solid-rocket boosters, and Aerojet Rocketdyne supplies the RS-25 main engines. First flight came on 16 November 2022 with the uncrewed Artemis 1 lunar test. Programme spending reached ~$23 billion through Artemis 1, with each launch costing roughly $4 billion. The rocket flies exclusively for NASA Artemis lunar work and, later, Mars missions.

SLS Block 1, the current configuration, comprises a Boeing Core Stage powered by four Aerojet Rocketdyne RS-25 engines — refurbished Space Shuttle Main Engines producing 2.2 GN combined thrust — flanked by two Northrop Grumman 5-segment solid rocket boosters at 16.0 GN each, topped by the Interim Cryogenic Propulsion Stage (ICPS). Lift performance is 95 metric tons to low Earth orbit and 27 metric tons through trans-lunar injection. The stack stands 98 m tall and weighs 2,608 metric tons fully fuelled. Block 1B (planned 2028+) swaps ICPS for the Exploration Upper Stage (EUS), lifting payload to 105 metric tons to LEO. Block 2 (planned 2030+) introduces upgraded boosters and RS-25E engines for 130 metric tons.

Artemis 1 lifted off on 16 November 2022, sending an Orion capsule on a 25-day uncrewed loop around the Moon — both the SLS maiden flight and the first beyond-LEO crew vehicle since Apollo. Artemis 2, planned for 2025, will fly four astronauts on a circumlunar pass, the first crewed lunar flight since Apollo 17 in 1972. Artemis 3, planned for 2026-2027, will land two astronauts at the lunar South Pole using a Human Landing System derived from SpaceX Starship. Further Artemis flights run through Artemis 10 and beyond into the mid-2030s. SLS and Starship occupy overlapping but distinct roles: SLS carries Orion and its crew, while Starship handles cargo and the surface landing — and may eventually take over crew launches as well.

For Kids — a shorter, friendlier version

The Space Launch System, or SLS, is a huge American rocket built by NASA. It is the most powerful rocket flying today. The SLS launches the Orion spacecraft and sends astronauts toward the Moon as part of the Artemis program.

The SLS first flew in November 2022 on a test mission called Artemis 1, without any people on board. The rocket sent a small Orion capsule on a loop around the Moon. The next flight, Artemis 2, will carry four astronauts on the same kind of trip around the Moon.

The SLS is taller than a 30-story building. It is heavier than 500 elephants when fully loaded with fuel. The rocket has four big main engines on the bottom plus two long white side boosters. The main engines are actually reused engines from the old Space Shuttle.

Each SLS launch costs about four billion dollars, which is very expensive. The Boeing-built core stage holds the liquid fuel and the four main engines. Even though the SLS is costly, only it is powerful enough to send astronauts and a heavy capsule all the way to the Moon today.

Fun Facts

  • The SLS is the most powerful rocket flying today.
  • Its main engines are reused engines from the old Space Shuttle.
  • The rocket first flew in November 2022 without astronauts.
  • The SLS is taller than a 30-story building.
  • Boeing builds the giant core stage, where the fuel and main engines live.
  • Each launch costs about four billion dollars.

Kids’ Questions

Why is the SLS so big?

To go all the way to the Moon, a rocket needs to carry a lot of fuel, a heavy spacecraft, and sometimes a lander too. Only a giant rocket can lift all that into space. The SLS is the only American rocket today big enough for crewed Moon trips.

Why is the SLS so expensive?

The SLS is built using older Space Shuttle parts and engines, which are very pricey to refurbish. Each engine costs about a hundred million dollars and gets used only once. Many people hope newer rockets like SpaceX Starship will be much cheaper in the future.

Variants

SLS Block 1 (2022-present)
Current variant. 95 tons LEO. ICPS upper stage.
SLS Block 1B (planned 2028+)
EUS upper stage. 105 tons LEO.
SLS Block 2 (planned 2030+)
Upgraded boosters. 130 tons LEO.

Notable Operators

NASA Artemis Program (2022-present)
Sole operator. Lunar and Mars-class missions.

Frequently Asked Questions

Why does SLS use refurbished Space Shuttle engines?

SLS Block 1 draws on 16 refurbished RS-25 engines pulled from the retired Shuttle fleet's Space Shuttle Main Engine (SSME) inventory. Three factors drove the refurbish-versus-new-build choice: (1) Cost — Aerojet Rocketdyne could refurbish existing engines for ~$40 million each against ~$150 million for new builds; (2) Risk — refurbished engines carry flight heritage and decades of Shuttle service data, whereas new builds would have demanded fresh ground and flight test campaigns; (3) Schedule — refurbishment matched the 2022 first-flight target, while new-build production would have pushed maiden launch to ~2025+. The trade-off is finite supply: 16 RS-25 engines cover the first 4 SLS launches, after which newly-built RS-25E engines from Aerojet Rocketdyne Stennis take over. Each RS-25 is expended on every flight — a sharp contrast to SpaceX's reusable Merlin and Raptor engines.

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