What is NASA's Human Landing System (HLS)?

How it works

NASA describes the Human Landing System as the transportation that takes Artemis astronauts to the lunar surface. Crews board the lander in lunar orbit, descend, work on the surface and ride it back up to orbit. They travel from Earth and return home in a separate spacecraft, Orion.

NASA is buying the landers from two companies under firm-fixed-price contracts, according to a March 2026 audit by NASA's Office of Inspector General (OIG). It says the contracts pay out only as agreed milestones are met. The audit describes SpaceX's lander, a version of its Starship, as about 171 feet tall, under a contract originally worth up to about $4.3 billion. Blue Origin is developing the 52-foot Blue Moon under an award of about $3.1 billion made in May 2023.

Both designs must be refueled in space. For SpaceX, the audit describes a depot in low Earth orbit filled by more than 10 tanker flights before the lander takes on propellant and heads for lunar orbit.

Why it matters

The OIG found that NASA had kept contract costs under control but that lander development problems had delayed planned Artemis missions. It found both companies behind schedule and SpaceX's lander delayed at least two years.

Transferring super-cold propellant between vehicles in space had never been done. The audit said NASA's lander program ranks it among the most significant technical challenges. It added that NASA cannot rescue a crew stranded in space or on the lunar surface.

NASA has obligated $6.9 billion for lander development since 2019 and estimates it will spend $18.3 billion through fiscal 2030, the OIG reported.

Where things stand in 2026

NASA announced a new plan on February 27, 2026, after the OIG had completed its audit work. Artemis III, previously planned as the first landing, became a 2027 mission in low Earth orbit to test docking between Orion and one or both commercial landers. The first landing moved to Artemis IV, which NASA said it was still targeting for early 2028, with lander readiness deciding which company flies it.

In July 2026, NASA said both companies are to fly test versions of their landers on Artemis III. Up to two astronauts would enter Blue Origin's test lander and none SpaceX's.

Starship reached orbit for the first time on September 28, 2026. Space.com noted that SpaceX had not yet demonstrated refueling in orbit.