Starship HLS facts for kids
A picture showing a future Starship HLS on the Moon
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| Manufacturer | SpaceX |
|---|---|
| Country of origin | United States |
| Operator | SpaceX |
| Applications | Lunar lander |
| Specifications | |
| Spacecraft type | Crewed, reusable |
| Crew capacity | 2–4 |
| Volume | 614 m3 (21,700 cu ft) |
| Regime | Cislunar space |
| Dimensions | |
| Diameter | 9 m (30 ft) |
| Capacity | |
| Payload to lunar surface | 100,000 kg (220,000 lb) |
| Production | |
| Status | In development |
| Maiden launch | 2027 (planned) |
| Related spacecraft | |
| Derived from | SpaceX Starship (spacecraft) |
| Flown with | SpaceX Super Heavy |
| Starship HLS | |
| Engines |
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| Fuel | CH 4 / LOX |
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Starship HLS stands for Human Landing System. It is a special version of the Starship spacecraft. This vehicle is designed to carry astronauts from orbit around the Moon down to its surface and then back again.
SpaceX is building Starship HLS for NASA. It is a key part of NASA's Artemis program, which aims to land astronauts on the Moon.
The plan is for a Super Heavy rocket to launch Starship HLS into orbit around Earth. There, other Starship tanker spacecraft will fill it with fuel. After refueling, Starship HLS will travel to a special orbit around the Moon called a near-rectilinear halo orbit (NRHO).
In lunar orbit, Starship HLS will meet up with a crewed Orion spacecraft. The Orion spacecraft is launched from Earth by NASA's Space Launch System (SLS) rocket. A team of astronauts will move from Orion to Starship HLS. Then, the HLS will land on the Moon for about seven days, including at least five spacewalks (called EVAs). After their mission, it will take the crew back to Orion in lunar orbit.
In April 2021, NASA chose SpaceX to develop and build Starship HLS. This was part of a contract for the Human Landing System. An uncrewed test flight, originally planned for 2025 to show a successful Moon landing, was delayed. Following that test, a crewed lunar landing with Starship HLS is expected as part of the Artemis IV mission, which is scheduled for early 2028.
SpaceX has been developing the Starship itself since the mid-22010s. However, the special HLS version is being funded by NASA's Human Landing System contracts.
Contents
Exploring the Starship Human Landing System
What is Starship HLS?
The Starship Human Landing System program involves several types of Starship spacecraft. These include the Starship HLS ship, which is made to work on and near the Moon. There is also a Starship depot that will store fuel in Earth orbit. Finally, Starship tankers will make many trips from Earth to orbit to bring fuel and oxygen to the depot.
For one mission to land humans on the Moon, all three types of Starship will work together. They will also dock with another NASA spacecraft in a special orbit around the Moon.
Unlike the regular Starship, the HLS and depot versions do not return to Earth's atmosphere. This means they do not need a heat shield or fins for re-entry. Removing these parts makes the spacecraft lighter. This means fewer tanker launches are needed to refuel them in orbit. Like other Starships, the HLS and depot ships have six Raptor engines. These engines are used for launch and most of the landing and ascent phases.
When Starship HLS is close to the Moon's surface (within 100 meters), it is planned to use special landing engines. These engines are in the middle of the spacecraft. They help avoid kicking up too much lunar dust with their exhaust. These landing engines burn gaseous oxygen and methane. The main Raptor engines use liquid oxygen and methane. Solar panels around the ship provide electricity. Starship HLS can stay in lunar orbit for 100 days.
NASA wants to keep the design of Starship HLS as similar as possible to other Starship versions. This helps speed up development and testing. It also ensures that the ships are ready on time for missions.
Both the Starship HLS and the Starship depot use special insulating tiles. These tiles protect them from tiny space rocks and keep the super-cold liquid oxygen and methane fuel from getting warm. These in-space tiles are different from the ceramic tiles on Starships that return to Earth.
Starship HLS for Cargo Missions
In April 2024, NASA announced that a version of the lander specifically for carrying cargo was being developed. NASA expects this cargo version to be ready and in use by the Artemis VII mission. This cargo variant will be called Human-class Delivery Landers by NASA. As of June 2024, these are the largest capacity landers NASA has for lunar exploration.
How Starship HLS Missions Work
Fueling Up in Space
A test to transfer fuel between Starships in orbit was optimistically scheduled for 2026. However, as of March 2026, this demonstration had not yet happened. Lessons learned from other projects, like LOXSAT, might help with this.
Before the Starship HLS leaves Earth, a Starship configured as a fuel depot is launched into Earth orbit. This depot is then filled by many Starship tanker flights. Between four and fourteen tanker flights are needed to fill the depot. So, the HLS mission uses the Super Heavy booster, the HLS lander, and the tanker and depot Starship variants.
In 2021, Elon Musk said "four to eight" tanker launches would be needed. The US Government Accountability Office (GAO) said "16 launches overall" would be required. In 2023, a NASA official estimated the number of Starship launches for one lunar landing to be "in the high teens." In 2024, a SpaceX vice president estimated "around 10" tanker launches. These launches need to happen quickly to avoid losing too much super-cold fuel.
After the fuel depot is full, the Starship HLS vehicle launches. It meets the depot in Earth orbit and refuels. Then, it travels from Earth orbit to lunar orbit.
Once Starship HLS is in its special orbit around the Moon (NRHO), an Orion spacecraft is launched by a Space Launch System rocket. Orion docks with the waiting Starship HLS lander to transfer astronauts. After two to four crew members move into the HLS, it leaves Orion and descends to the Moon's surface. After exploring the Moon, Starship HLS lifts off and returns to lunar orbit to meet Orion again. The crew then transfers back to Orion and heads for Earth. It is possible that Starship HLS could be refueled in orbit to carry more crews and cargo to the Moon in the future.
The Story of Starship HLS
Why a New Lunar Lander?
In the early 2010s, NASA planned to use the Orion spacecraft and the Space Launch System (SLS) to land astronauts on the Moon. The Orion capsule's design came from an older lunar program called Constellation. The SLS rocket was developed after the Space Shuttle retired in 2011. However, the SLS cannot launch Orion directly into a low lunar orbit, like the Saturn V rocket did during the Apollo program.
The closest the SLS can launch Orion to the Moon is into NRHO. This is an elliptical orbit that gets close to the Moon. Landing on the Moon from NRHO needs much more energy than from a low lunar orbit. It also only allows a landing opportunity once every 6.5 days.
To solve these problems, NASA asked private companies in 2018 to develop a Human Landing System (HLS). These HLS vehicles needed to travel from Earth to NRHO, meet Orion, land on the Moon, and then return to NRHO to dock with Orion again.
SpaceX had been planning to build a large vehicle for traveling to other planets since the 2000s. Their goal was to help colonize Mars. In response to NASA's request, SpaceX changed their Starship design. They created a version, Starship HLS, to carry NASA astronauts to the Moon from NRHO.
Choosing the Lunar Lander
NASA first contracted SpaceX for design work on a Starship variant in May 2020. This was part of the Artemis III mission. In April 2021, Starship HLS was chosen for full development and funding. NASA selected it to land "the first woman and the next man" on the Moon for the Artemis III mission. This mission was later delayed by NASA until Artemis IV.
- How Starship HLS was chosen
In 2021, NASA signed a contract with SpaceX worth $2.89 billion. This money was for developing and building the Starship HLS lunar lander. It also covered two flights: an uncrewed test mission and a crewed lunar landing.
Starship HLS was first shown to the public when NASA selected it in April 2020 for a design study. SpaceX was one of three teams chosen to develop competing lunar lander designs for the Artemis program. The other landers were proposed by Dynetics and Blue Origin. NASA had planned to choose up to two landers for initial test flights.
On April 16, 2021, NASA chose only Starship HLS for crewed lunar lander development. This included two lunar demonstration flights—one without a crew and one with a crew—no earlier than 2024. The contract was worth $2.89 billion. Two NASA Artemis astronauts are planned to land on the first crewed Starship HLS mission. NASA had previously said it preferred to fund multiple lander designs. However, due to budget limits from the US Congress, only one design was chosen for the first crewed landing. NASA stated that the other proposals could still be considered for future lunar landing contracts.
- Challenges from other companies
On April 26, 2021, Blue Origin and Dynetics separately raised concerns about the contract award to SpaceX. On July 30, 2021, the US Government Accountability Office (GAO) reviewed these concerns. They found that NASA had followed the rules in awarding the contract to SpaceX. SpaceX had offered a much lower cost and a more capable design. Soon after, NASA made the first $300 million payment to SpaceX. The challenges caused a 95-day delay in NASA authorizing work on the contract.
On August 13, 2021, Blue Origin took further legal action. They challenged "NASA's unlawful and improper evaluation of proposals." Blue Origin asked the court to stop NASA from spending more money on the contract with SpaceX. NASA stopped work on the contract on August 19. Many people criticized Blue Origin for causing delays to the Artemis program.
On November 4, 2021, the court decided against Blue Origin's challenge. NASA announced that it would restart work with SpaceX as soon as possible.
- Artemis IV contract (Option B)
On March 23, 2022, NASA announced it would use an option under the SpaceX HLS contract, called Option B. This would allow a second-generation Starship HLS design to fly a demonstration mission after Artemis III.
On November 15, 2022, NASA announced it had given SpaceX the Option B contract modification, worth $1.15 billion. This crewed landing is planned as part of Artemis IV. The Option B HLS will meet NASA's needs for a "sustainable" HLS. This includes supporting four crew members and delivering more cargo to the Moon.
- Other NASA contracts
After NASA awarded the first contract to SpaceX, Congress asked NASA to add a second sustainable HLS design. This design had to come from a different company. NASA created "Appendix P" for this. They specified a lander that would be used for Artemis V as its crewed demonstration flight. In May 2023, Blue Origin received $3.4 billion from NASA to develop their Blue Moon lunar lander. NASA plans to have Starship HLS Option B and the Blue Moon lander compete for Artemis missions after Artemis V.
Recent Developments (2021–Present)
In 2021, NASA's internal watchdog (OIG) warned that the HLS development schedule was too ambitious. They noted that major NASA space programs usually took about 8.5 years from contract award to first flight. The HLS Program was trying to do it in about half that time. The OIG also pointed out that the Apollo Lunar Lander took about 6 years to develop. It also received much more funding, adjusted for inflation. Based on past delays, the OIG estimated the HLS Program could face delays of up to 3.4 years.
In June 2023, a NASA chief mentioned that the Starship HLS design review was delayed. This review was needed before more funds could be released to SpaceX. It was delayed until SpaceX completed an in-orbit refueling demonstration. The head of NASA's Moon and Mars exploration strategy said that the delay of Artemis III from 2025 to 2026 was partly due to "development challenges" with its contractors.
In November 2023, the US GAO reported on several challenges facing the Artemis program. They noted that as of September 2023, the NASA HLS program had delayed 8 out of 13 key events by at least 6 months. Two events were delayed to the year of launch (2025 at the time). The GAO also identified the development of the Raptor engine as a "top risk." However, SpaceX considered the Raptor engine technology to be quite mature. The GAO noted that SpaceX had made limited progress on technologies for in-orbit refueling and storing super-cold fuel. The GAO concluded that the Artemis III crewed lunar landing was unlikely to happen in 2025, with early 2027 being a more probable launch date.
NASA astronauts tested the elevator concept for moving between the Starship HLS cabin and the lunar surface in December 2023.
In January 2024, NASA and SpaceX stated that the uncrewed Starship HLS lunar landing test was expected in 2025. Artemis III was delayed to no earlier than September 2026. This delay was partly due to issues with Orion's heat shield during Artemis I. The test was later delayed until 2027.
By February 2024, SpaceX had fully tested the life support system. NASA also performed a full-scale test of the Starship HLS to Orion docking system. In the same month, NASA said SpaceX had completed over 30 HLS-specific milestones. These included defining and testing hardware for power, communications, navigation, propulsion, life support, and protection from space environments.
On March 14, 2024, SpaceX successfully tested transferring fuel inside a Starship during Integrated Flight Test 3. In April 2024, NASA reported that a cargo version of the lander was being developed. NASA expects this variant to be ready and in service by Artemis VII.
In a meeting on September 10, 2024, lawmakers Brian Babin and Haley Stevens shared concerns. They worried that the speed of license processing by the FAA could affect the Artemis program. Both Blue Origin and SpaceX HLS landers will launch using commercial licenses. After a two-month delay by the FAA for Starship flight test 5, SpaceX mentioned that government approvals slowed down their flight schedule for Artemis.
In October 2024, NASA stated that the flight tests for transferring fuel between ships were planned to start around March 2025 and finish by summer. NASA's design certification review was also planned for that time. However, as of March 2026, neither the demonstration nor the design certification review had occurred.
In October 2025, NASA planned to reopen the contract for the Artemis III mission because of delays in Starship's development.
See also
- Apollo program
- Blue Moon (spacecraft)
- Lanyue
- LK (spacecraft)
- List of crewed lunar landers
