Starship HLS
Starship HLS mission
Country of originUnited States
ApplicationsCrewed reusable lunar lander
Launch mass~1,320 t (2,910,000 lb)
RegimeCislunar space
Length50 m (164 ft 1 in)
Width9 m (29 ft 6 in)
StatusIn development
Maiden launchNET 2024
Related spacecraft
Derived fromSpaceX Starship (spacecraft)
Powered byRaptor, RCS thruster bank
PropellantCH4 / LOX

Starship HLS, or Starship Human Landing System, is a lunar lander variant of the Starship spacecraft that is slated to transfer astronauts from a lunar orbit to the surface of the Moon and back. It is being designed and built by SpaceX under the Human Landing System contract to NASA as a critical element of NASA's Artemis program to land a crew on the Moon no earlier than 2026.

The mission plan calls for a Super Heavy booster to launch a Starship HLS into an Earth orbit, where it will be refueled by multiple Starship tanker spacecraft before boosting itself into a lunar near-rectilinear halo orbit (NRHO). There, it will rendezvous with a crewed Orion spacecraft that will be launched from Earth by a NASA Space Launch System (SLS) launcher. A crew of two astronauts will transfer from Orion to HLS, which will then descend to the lunar surface for a stay of approximately 7 days which is to include five or more EVAs. It will then return the crew to Orion in NRHO.

In the third phase of its HLS procurement process NASA awarded SpaceX a contract in April 2021 to develop, produce, and demonstrate Starship HLS. An uncrewed test flight is planned for 2024 to demonstrate a successful landing on the Moon. Following that test, a crewed flight is expected to occur as part of the Artemis 3 mission, no earlier than December 2025.[1] NASA later contracted for an upgraded version of Starship HLS to be used on the Artemis 4 mission.[2]


Starship HLS is a variant of SpaceX's Starship spacecraft optimized to operate on and around the Moon. In contrast to the Starship spacecraft from which it derives, Starship HLS will never reenter an atmosphere, so it does not have a heat shield or flight control surfaces. In contrast to other HLS designs that proposed multiple stages, the entire spacecraft will land on the Moon and will then launch from the Moon. Like other Starship variants, Starship HLS has six Raptor engines mounted at the tail which are used when the Starship HLS acts as the second stage during the launch from Earth. They are also used as its primary propulsion system in all other flight phases. Within 100 meters of the lunar surface, the variant will utilize high‑thrust RCS thrusters located mid‑body to avoid plume impingement problems with the lunar regolith. The thrusters burn gaseous oxygen and methane instead of the liquid oxygen and methane used by the Raptors.[3][4]: 50:30  However, these thrusters may not be needed.[5] Starship HLS is supplied with electrical power by a band of solar panels around the circumference of the vehicle.[citation needed]

Starship HLS requires in-orbit propellant transfer in its mission profile. Prior to the launch of the HLS vehicle from Earth, a Starship variant configured as a propellant depot would be launched into an Earth orbit and then partially or fully filled by between four and fourteen[a] Starship tanker flights carrying propellant.[6] The Starship HLS vehicle would then launch and rendezvous with the already-loaded propellant depot and refuel before transiting from Earth orbit to Lunar orbit.[7]

Starship HLS incorporates the following design characteristics:[7]

Within the Artemis lunar landing architecture as of April 2021,[7] a NASA Orion spacecraft is planned to be launched by a Space Launch System rocket and rendezvous with a waiting Starship HLS lander in a near-rectilinear halo orbit around the Moon. The crew of Orion would then dock with, and transfer to Starship HLS, which would subsequently depart and descend to the lunar surface. After lunar surface operations, Starship HLS will lift-off from the Moon and return to lunar orbit to rendezvous with Orion. The crew then transfers back to Orion and departs for Earth. Although not confirmed yet, Starship HLS could, in theory, be refueled in orbit to carry more crews and cargo to the surface.[8][9]


Starship HLS builds on the SpaceX Starship system by adding a new spacecraft variant called Starship HLS. This spacecraft will be used in conjunction with the Starship booster (called Super Heavy) and two additional Starship spacecraft variants, "tanker" and "depot", that were already being planned prior to the HLS contract.

Starship system history

Further information: SpaceX Starship § History

The SpaceX Starship concept was initially conceived in the early 2010s as a spacecraft that would be principally built for the Mars colonization effort that SpaceX CEO Elon Musk has advocated since 2011,[10] with the first colonists arriving no earlier than the middle of the 2020s.[11]

By 2016, the scope became somewhat broader, when Musk realized the high-level design SpaceX had been working on for the Starship vehicle allowed for variants that would be suitable for interplanetary travel more generally, and could work both on planets with and without an atmosphere.[12] Lunar destination flights, however, were not generally emphasized by Musk, and he specifically stated that the Moon was not a necessary step on the path to Mars.[13][14]

By late 2018, SpaceX had specified the primary construction material for Starship to be stainless steel[15] – after approximately a year of building manufacturing pathfinder hardware out of carbon composite materials—and manufacture of the initial test article including pressure vessel construction for the liquid methane and liquid oxygen tanks began in early 2019.[16]

Between July 2019 and July 2021, seven Starship prototype vehicles, each with different vehicle design configurations and varied test objectives, flew a total of eight atmospheric test flights, all launched from the SpaceX South Texas launch site at Boca Chica, Texas.[17]

Starship HLS history

Main article: Human Landing System

Initial "Option A" Contract

Starship itself has been in privately-funded development by SpaceX since the mid-2010s, but the HLS (Human Landing System) variant is being developed under contracts with the United States' National Aeronautics and Space Administration (NASA). The initial contracted design work started in May 2020, with selection and funding for full-development occurring in April 2021, when Starship HLS was selected by NASA to land "the first woman and the next man" on the Moon during the Artemis 3 mission, potentially as early as 2024.

NASA signed a US$2.89 billion contract with SpaceX to develop and manufacture Starship HLS,[18] and to conduct two flights – an uncrewed demonstration mission, and a crewed lunar landing.[19][7] Starship HLS is intended to dock in a lunar NRHO with either the NASA Orion spacecraft or NASA lunar Gateway space station, in order to take on passengers before descending to the lunar surface and return them after ascent.

Starship HLS, with HLS being an initialism for Human Landing System, was first made public when it was initially selected by the NASA in April 2020 for a design study as part of their Artemis program, which aims to land humans on the Moon. SpaceX was one of three teams selected to develop competing lunar lander designs for the Artemis program over a year-long[20] period starting in May 2020.[20] The other landers in consideration were Dynetics HLS, developed by aerospace manufacturer Dynetics, and the Integrated Lander Vehicle, developed by a team led by Blue Origin.[8] NASA intended to later select and fund at most two of these landers to continue to perform initial demonstration flights.[21][9]

On 16 April 2021, NASA selected only Starship HLS for crewed lunar lander development[18] plus two lunar demonstration flights – one uncrewed and one crewed – no earlier than 2024. The contract is valued at US$2.89 billion over a number of years.[19][7] Two NASA Artemis astronauts are to land on the first crewed Starship HLS landing.[22] NASA had previously stated that it preferred to fund development of multiple Human Landing System proposals with dissimilar capabilities; however, "only one design was selected for an initial uncrewed demonstration and the first crewed landing, due to significant budget constraints" for the human landing system program imposed by US Congress. NASA stated that the unselected proposals – Dynetics HLS and Blue Origin ILV – as well as landers from other companies would be eligible for later lunar landing contracts.[7]

On 26 April 2021, Blue Origin and Dynetics separately protested the award to SpaceX at the US Government Accountability Office (GAO).[23] On 30 July 2021, the GAO rejected the protests and found that "NASA did not violate procurement law" in awarding the contract to SpaceX, who bid a much lower cost and more capable human and cargo lunar landing capability for NASA Artemis.[23][24] Soon after GAO rejected the appeal, NASA made the initial $300 million contract payment to SpaceX.[25] The protest action delayed NASA from authorizing work on the contract, and thus delayed the start of work by SpaceX for 95 days.[26]

Main article: Blue Origin v. United States & Space Exploration Technologies Corp.

On 13 August 2021,[27] Blue Origin filed a lawsuit in the US Court of Federal Claims challenging "NASA's unlawful and improper evaluation of proposals".[26][28] Blue Origin asked the court for an injunction to halt further spending by NASA on the existing contract with SpaceX,[29] and NASA stopped work on the contract on 19 August, after SpaceX had been allowed to work on the NASA-specific parts of Starship HLS for just three weeks since the work had been previously halted in April.[27] Reactions to the lawsuit were negative, with many criticizing Blue Origin for causing unnecessary delays to the Artemis program.[30][31][32] On 4 November, the court granted the federal government's motion to dismiss the case,[33][34][35] and NASA announced that it would resume work with SpaceX as soon as possible.[36]

"Option B" contract

On 23 March 2022, NASA announced it would be exercising "option B", an option under the initial SpaceX HLS contract that would allow a second-generation Starship HLS design to conduct a demonstration mission after Artemis 3.[37]

On 15 November 2022, NASA announced the Option B award of US$1.15 billion, and announced that this crewed landing is to occur as part of Artemis 4.[2] The flight will include docking with the Gateway. The Option B HLS will meet NASA's requirements for a "sustainable" HLS. These include the ability to support a crew of four and longer-duration lunar surface stays.

Subsequent contracts

After NASA awarded the Option A contact to SpaceX, congress directed NASA to award a second HLS contract. NASA responded by creating "Appendix P" for a non-SpaceX sustainable HLS. This lander will be used for Artemis 5 as its crewed demonstration flight. In May 2023, Blue Origin was awarded $3.4 billion by NASA to develop their Blue Moon lunar lander, compared to the $2.89 billion of the original bid that had been awarded to SpaceX for Option A.[38][39] NASA intends to allow Starship HLS option B and the Blue Moon lander to compete for Artemis missions after Artemis 5.

See also


  1. ^ In the documentation of SpaceX's HLS bid, a conservative figure of 14 tanker flights is used. Musk has stated that with a tanker payload mass of 150 tons, four to eight tanker flights would be necessary, depending on the payload mass on Starship HLS itself and the intended fuel load (since the mission profile may allow for a less than full tank).


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  3. ^ Cummings, Nick (11 June 2020). Human Landing System: Putting Boots Back on the Moon. American Astronautical Society. Event occurs at 35:00–36:02. Retrieved 12 June 2020 – via YouTube. ... for the terminal descent of Starship, a few tens of meters before we touch down on the lunar surface, we actually use a high-thrust RCS system, so that we don't impinge on the surface of the Moon with the high-thrust Raptor engines. ... uses the same methane and oxygen propellants as Raptor.
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