Human Landing System

NASA's Human Landing System (HLS) programme is the agency's effort to acquire commercial lunar landers that can carry astronauts from lunar orbit to the Moon's surface and back. Originally intended to produce a single provider, the programme now spans two parallel contracts: SpaceX's Starship HLS (awarded 2021, valued at up to $4.5 billion) for Artemis III and IV, and Blue Origin's Blue Moon MK2 (awarded $3.4 billion in 2023) for Artemis V. NASA's Office of the Inspector General audited the programme in 2025 and found Starship HLS at least two years behind schedule, with disputes over manual control authority adding risk to the programme.

The architectural challenge is formidable. Neither lander launches from Earth; both must be pre-positioned in lunar near-rectilinear halo orbit after multiple propellant transfer flights. Starship HLS, at 52 metres tall, must land vertically on sloped polar terrain with an elevator to carry crew to the surface, a design the OIG has flagged as a significant stability and safety risk at the South Pole. Blue Moon MK2 uses heritage hydrolox propulsion and is a more conventional lander profile.

The HLS programme sits on the critical PATH for crewed lunar surface access. Without it, Artemis cannot land on the Moon regardless of whether SLS and Orion are ready. Delays to SpaceX's Starship milestones have already triggered discussions about mission replanning, and a NASA study concluded there is no credible rescue option if a crew is stranded on the lunar surface.