When NASA awarded SpaceX a $2.89 billion contract in April 2021 to develop the Human Landing System for the Artemis program, it marked a turning point not just for the company, but for the entire architecture of lunar exploration SpaceX Starship HLS: The Gamble Gets Bigger . The Starship HLS , a modified version of SpaceX's fully reusable launch vehicle , would become the largest and most capable lunar lander ever built. With a payload capacity of 100 metric tons to the lunar surface and a pressurized volume larger than the International Space Station's habitable space, Starship HLS dwarfs every lunar lander concept in history. It represents a radical departure from the minimalist approach that defined Apollo's Lunar Module , and a bet that sheer scale can solve problems that precision engineering alone cannot. SpaceX Conducts First Orbital Propellant Transfer Test in low Earth orbit" class="rounded-lg w-full shadow-lg border border-neutral-700"> AI-generated image Artist's concept of Starship orbital propellant transfer, a critical prerequisite for lunar missions. June 2026 Update: HLS Is Now the Artemis IV Gatekeeper NASA's latest Artemis planning moved the next crewed lander work into a different sequence. Artemis III is now being defined as a low Earth orbit rendezvous and docking test with Orion, SpaceX's Starship HLS pathfinder, and Blue Origin's Blue Moon Mark 2 pathfinder. The first post-Artemis II surface return has shifted to Artemis IV, which makes Starship's 2026 long-duration flight and in-space propellant transfer tests the schedule items to watch. SpaceX says it has completed 49 HLS contract milestones , including work on landing legs, docking adapters, and Raptor engine testing. The open risk is no longer whether NASA wants Starship in the lunar stack. It is whether SpaceX can prove the tanker, depot, docking, and cryogenic transfer chain quickly enough for a 2028 landing campaign. From Mars Vehicle to Moon Lander SpaceX's journey to becoming NASA's primary lunar transportation provider began not with the Moon, but with Mars. The Starship program , originally announced as the Interplanetary Transport System in 2016 , was conceived as a fully reusable vehicle capable of establishing a human presence on Mars. Founded in 2002 by Elon Musk with the explicit goal of making life multi-planetary, SpaceX spent its first decade developing the Falcon 1, Falcon 9, and Dragon spacecraft, building the operational track record and engineering capability that would eventually underpin the Starship program. The pivot to lunar operations came when NASA's Artemis program needed a lander that could meet ambitious requirements: carrying at least two astronauts to the lunar surface, supporting extended stays, and delivering significant cargo. SpaceX proposed a modified Starship , and its audacious bid beat out competing proposals from Blue Origin's National Team and Dynetics , in part because of its dramatically lower cost and higher capability. The initial contract covered development and a crewed demonstration mission that NASA once mapped to Artemis III. The program has since been reshuffled. NASA's 2026 plan now uses Artemis III as an Earth-orbit systems test, with Orion demonstrating rendezvous and docking operations alongside commercial lander pathfinders before a later lunar landing attempt. In November 2022, NASA exercised an option worth approximately $1.15 billion for a second SpaceX landing mission, bringing the total HLS contract value to over $4 billion. The value of that work is now judged less by a single mission label and more by whether Starship can mature into a repeatable lunar logistics system. $4B+ Total HLS Contract Value 100 t Payload to Lunar Surface 614 m³ Pressurized Volume 52 m Vehicle Height 9 m Diameter 6 Raptor Engines The Orbital Refueling Challenge The single greatest technical challenge facing Starship HLS isn't landing on the Moon , it's getting there fully fueled. Because Starship burns most of its propellant reaching orbit, a lunar mission requires the HLS variant to be refueled in space before it can boost toward the Moon. This demands a fleet of Starship tanker vehicles and an orbital propellant depot. NASA expects that between four and fourteen tanker flights could be needed to fully fuel an HLS vehicle in orbit, depending on the final mission design. The propellant transfer campaign has slipped from earlier public schedules, but SpaceX now identifies two HLS-linked tests as the next major markers: a long-duration Starship orbital flight and an in-space propellant transfer demonstration. Both are targeted for 2026, with timing tied to the upgraded Starship architecture and the results of upcoming flight tests. The operational sequence remains daunting. A depot Starship reaches orbit first, tankers ferry liquid methane and liquid oxygen to fill it, then the HLS vehicle docks and receives the propellant it needs for trans-lunar injection. The lunar lander story is therefore also a launch cadence story, a ground systems story, and a cryogenic storage story. This represents an unprecedented operational tempo. No organization has ever attempted rapid-cadence orbital refueling at this scale. SpaceX aims for biweekly launches from a single pad , with a stretch goal of weekly launches using two pads. The cryogenic propellant management challenge , keeping methane and oxygen cold enough to remain liquid in orbit for weeks , requires specialized insulating tiles distinct from the heat shield tiles used during atmospheric reentry. AI-generated image Raptor engines power Starship HLS during the majority of its lunar descent and ascent phases. Hardware and Technology Starship HLS is derived from the standard Starship upper stage but with critical modifications for lunar operations. At 52.3 meters tall and 9 meters in diameter , it towers over every previous lunar lander. The vehicle is powered by three sea-level Raptor engines and three vacuum-optimized Raptor engines, all burning liquid methane and liquid oxygen. Unlike the standard Starship, the HLS variant does not reenter Earth's atmosphere, which eliminates the need for a heat shield and aerodynamic control surfaces. This mass reduction translates directly into additional payload capacity. The vehicle is wrapped in a band of solar panels for electrical power generation and can loiter in lunar orbit for up to 100 days . One of the more novel design challenges is crew access. Because the crew cabin sits approximately 50 meters above the lunar surface, SpaceX has designed an elevator system to lower astronauts and cargo to the ground. When close to the surface (within 100 meters), HLS switches from its main Raptor engines to dedicated high-thrust landing engines mounted on the mid-body of the vehicle. These engines use gaseous methane and oxygen to minimize plume interaction with lunar regolith , a critical concern given that high-velocity exhaust can sandblast equipment and create dangerous debris clouds. Key Technical Innovation: Cryogenic Propellant Management Starship HLS and the orbital depot use specialized insulating tiles that provide micrometeoroid and orbital debris (MMOD) protection while keeping cryogenic propellants cold enough for long-duration storage. This technology is distinct from the ceramic heat shield tiles on atmospheric-reentry Starships and represents a critical new capability for cislunar operations. Starship V3: The Test Program Now Carries the Lunar Schedule While HLS development continues, SpaceX is pushing the base Starship vehicle into the version that matters most for Artemis. The upgraded V3 architecture is expected to carry the docking, propellant-transfer, and long-duration orbital capabilities needed for a lunar lander campaign. That makes every integrated flight test a proxy indicator for HLS schedule risk. The most important milestones are no longer headline altitude or splashdown targets. They are orbital endurance, controlled rendezvous