SLS Rocket: the launch vehicle behind Artemis

SLS is NASA Space Launch System, the heavy-lift rocket used for Artemis missions. It is designed to send the Orion spacecraft, astronauts and mission hardware toward the Moon. The rocket is a central part of the Artemis stack alongside Orion and the ground systems at Kennedy Space Center.

SLS lifts Orion and its crew from Kennedy Space Center. Commercial landers, launched separately, are planned to carry astronauts from lunar orbit to the surface on landing missions.

Sending humans beyond low Earth orbit requires enormous energy. The rocket must lift Orion, the crew, support systems and mission hardware onto a path that can reach lunar space. A lunar mission is not simply a bigger version of a satellite launch; it is a deep-space transportation problem.

The rocket has a core stage, solid rocket boosters and an upper stage. Orion sits above them. Together they give the crew spacecraft the energy needed to leave Earth orbit.

Block 1B was a planned more capable SLS configuration with a larger upper stage. It appears in older NASA descriptions of Artemis IV, along with plans to carry additional cargo.

NASA's current campaign overview says it is standardizing the SLS configuration beginning with Artemis IV. Some older NASA hardware reference pages still describe Block 1B as the Artemis IV rocket. Those pages reflect an earlier architecture and should not be treated as the latest mission plan.

SLS launches the crew aboard Orion, but Orion does not descend to the lunar surface. A separate commercial human landing system is needed to carry astronauts from lunar orbit to the ground and back.

That is why Artemis III's planned docking test matters: crews and engineers need to prove the vehicles can work together before attempting a surface landing.