SpaceX Starship

Starship

Left: Starship spacecraft SN16 on display Right: Super Heavy booster BN4
Function	Intercontinental transport Orbital launch and re-entry Extraterrestial lander
Manufacturer	SpaceX
Country of origin	United States
Size
Height	120 m (390 ft)
Diameter	9 m (30 ft)
Mass	5,000 t 11,000,000 lb
Stages	2
Launch history
Status	In development
Launch sites	Boca Chica launch site LC-39A Phobos and Deimos
Payload to low Earth orbit
Altitude	500 km (310 mi)
Orbital inclination	98.9°
Mass	>100 metric tons (220,000 lb) reusable
Volume	c. 1,100 m3 (39,000 cu ft)
Payload to higher Earth orbits, the Moon or Mars
Mass	>100 metric tons (220,000 lb) after one or multiple refuellings
Volume	c. 1,100 m3 (39,000 cu ft)
First stage – Super Heavy
Height	70 m (230 ft)
Propellant mass	3,400 metric tons (7,500,000 lb)
Powered by	33 Raptor
Maximum thrust	c. 72 MN (16,000,000 lbf)
Propellant	Liquid CH4 and O2
Second stage – Starship
Height	50 m (160 ft)
Propellant mass	1,200 metric tons (2,600,000 lb)
Powered by	3 Raptor 3 Raptor Vacuum
Propellant	Liquid CH4 and O2

Starship is a reusable launch system in development by American aerospace company SpaceX. The launch system includes a first stage named Super Heavy and a second stage named Starship; both are made from stainless steel and designed to hold liquid oxygen and liquid methane fuel. During liftoff, Super Heavy's 33 Raptor engines produce 72 MN (16,000,000 lb_f) of thrust, twice that of a Saturn V rocket. Three Raptors are optimized to operate in the vacuum of space, three others are used to land vertically. Two pairs of flaps control its descent. Launch pads and towers stack Starship's stages and aid launch and recovery operations. Starship payloads to low Earth orbit are more than 100 metric tons (220,000 lb). Higher Earth orbits, the Moon, and Mars are accessible after being refueled by tanker Starship.

In 2005, the first publicly announced rocket concept with Starship-level payloads from SpaceX was BFR, burning a mixture of RP-1 and liquid oxygen. After major changes, on 25 July 2019, Starhopper performed the first successful flight by any Starship test article. The flight launched from the Boca Chica launch site, which as of October 2021 was the main build and launch site. The first complete Starship test article was SN8, which launched and crashed upon landing on 9 December 2020. On 5 May 2021, SN15 became the first test article to launch and land successfully. As of October 2021, SN20 and BN4 were expected to become the first test article to attempt going to orbit. Starship launch system is incorporated into upcoming and envisioned space missions, such as the dearMoon project, NASA's Artemis program, and SpaceX's Mars program.

Design

As of October 2021, the Starship launch system consists of two stages: a Super Heavy booster and a Starship spacecraft. Starship's body is made from welded 9 m (30 ft) diameter rings. They are 3.97 mm (0.156 in) thick, 1.8 m (5 ft 11 in) tall, and composed of SAE 304L stainless steel. The goal of Starship launch system is to be a fully reusable orbital launch and reentry vehicle.

Super Heavy booster

When launched, the Super Heavy booster accelerates the spacecraft to Mach 8 or 9 and lands itself on the launch tower's arms. The booster is 70 m (230 ft) tall. The bottom of the booster houses up to 33 sea-level optimized Raptors that produce 72 MN (16,000,000 lb_f) of thrust during liftoff. Musk stated in an interview that the tanks hold 3,600 metric tons (7,900,000 lb) of propellant, consisting of about 2,800 metric tons (6,200,000 lb) of liquid oxygen and 800 metric tons (1,800,000 lb) of liquid methane. Musk also noted that Super Heavy might gimbal its engine to spin the whole launch system, causing the booster to separate from the spacecraft.

The Super Heavy booster contains components such as four grid fins, a flight computer, vents, and batteries. The grid fins installed above the booster are controlled by electric motors. They control Super Heavy's descent and touchdown onto the launch tower's pair of mechanical arms. The grid fins are not spaced out evenly, instead, they are positioned closer to control the booster's pitch while landing. As of August 2021, SpaceX plans to not retract the grid fins during launch, citing complexity, mass increase, and insignificant drag for the rationale. The company also plans to vent evaporated gas inside the propellant tanks as in a reaction control system. The vents would control the booster's altitude and orientation during flight.

Starship spacecraft

The Starship spacecraft is attached to the top of the booster. It is 50 m (160 ft) tall and has a total propellant capacity of 1,200 metric tons (2,600,000 lb). The bottom section houses six Raptors: three are optimized for atmospheric pressure, and three for vacuum operation. The liquid oxygen and liquid methane propellant tanks are positioned above the tanks, separated by a dome containing a small, spherical liquid methane header tank.

On top of the tanks is the payload section. It houses a liquid oxygen header tank and payload. For cargo, a large clamshell door replaces conventional payload fairings, which can capture, store, and return payload to Earth. The payload door is closed during launch, opens to release payload once in orbit, then closes again during reentry. SpaceX also considers using the clamshell door feature to capture space debris at Earth orbit. In the crewed variant, the payload bay houses cabins and other facilities. In an interview, Musk stated that Starship would not have a launch escape system because SpaceX is confident that Starship would be safe and reliable in its finalized design.

Once it separates from Super Heavy, Starship accelerates to orbit. The flaps control the spacecraft's attitude during reentry and descent. From its horizontal position moving at terminal velocity, Starship fires its engines to flip back up and slow itself down. Starship has two pairs of vertically installed flaps, perpendicular to the tangent line of its body. A larger pair of flaps sit at the bottom of Starship, and a smaller pair is placed on the nose cone. The windward side of the spacecraft is covered by a heat shield made from ceramic hexagon tiles designed to withstand up to 1,350 °C (2,460 °F) and prevent plasma from accelerating through the gap. The heat shield goal is to be used multiple times with little refurbishment in-between. Simulations from SpaceX showed that 99.9% of Starship's kinetic energy can dissipate upon reentry to Earth, but the thinner Mars atmosphere can dissipate only 99% of its kinetic energy.

Variants

SpaceX plans to build multiple Starship variants. The original design will be used to transport cargo on missions. This variant is used to deliver, deploy, and pick up cargo in orbit by a large cargo bay door. Starship tanker is optimized to orbit its propellant and refuel rendezvoused spacecraft. Starship Mars's variant might carry 100 passengers and cargo to Mars, as Elon Musk proposed at the 67th International Astronautical Congress.

Another Starship variant could carry passengers on long-distance sub-orbital flights. Its president Gwynne Shotwell predicted that it could be cost-competitive with business class travel. The craft would travel between spaceports, with flight times of some 40 minutes from New York City to Shanghai.

Starship Human Landing System (Starship HLS) is another variant of Starship, targeted to serve as the crewed lunar lander for the Artemis program. Starship HLS lacks a heat shield and body flaps. This spacecraft will have a docking system, solar panels, and extra landing thrusters placed in the middle of the ship to minimize dust. However, in an interview in August 2021, Musk mentioned that Starship SLS might have the same engine placement as a normal Starship. Another variant of Starship might ferry heavy payloads to the Moon's surface for the Commercial Lunar Payload Services program.

Ground infrastructure

Starship launch tower at the Boca Chica launch site

Starship may launch at SpaceX's Boca Chica launch site, offshore platforms, and Kennedy Space Center Launch Complex 39A (LC-39A). The Boca Chica launch site, referred to by SpaceX as Starbase, is planned to be the first to launch Starship to orbit. The offshore platforms, named Phobos and Deimos after the moons of Mars, were former oil drilling rigs owned by Valaris. As of January 2021, SpaceX is actively constructing the Boca Chica launch site, and as of August 2021, Phobos and Deimos' construction is not prioritized.

The launch and landing pad consists of a launch mount, a tower, and tanks. The launch tower in Boca Chica is 146 m (479 ft) tall, consisting of 143 m (469 ft) tall steel truss sections and a 3 m (9.8 ft) tall lightning rod on top. The launch tower has a pair of quick-disconnect claws and a large crane. These components allow the launch tower to lift, fuel, and stabilize Starships on the launch pad. For landing, the rocket stages will initially touch down on drone ships or landing pads near the launch site.

In the future, the launch tower might recover the Super Heavy directly, using a cable system that matches the incoming booster's velocity and a pair of mechanical steel arms that move around pivots. The tower's arms catch the booster by closing and letting the booster's grid fins touch down on them.

Raptor engine

Main article: SpaceX Raptor

Both stages are equipped with Raptor engines. A Raptor engine can produce approximately 2.3 MN (520,000 lb_f) of thrust. It uses a liquid methane and oxygen full-flow staged combustion cycle. In an interview with Tim Dodd, Musk stated that Raptors would burn liquid oxygen to liquid methane in a ratio of 3.5 to 3.7, which is somewhat less than a chemically perfect ratio. Musk also mentioned that most of the original Raptor variant is produced in a SpaceX facility in McGregor, while SpaceX's factory at Hawthorne would be used to produce Raptor Vacuum and testing new engine design.

For the Raptor Vacuum variant, it is equipped with nozzle extension with a throat area to exit area of 1 to 80. The Raptor Vacuum is designed to increase Raptor's specific impulse in space. Musk clarified that the Raptor Vacuum has a specific impulse of 378 s (3.71 km/s). The engine's goal is to reach 380 s (3.73 km/s).

Generally, a full-flow staged combustion cycle rocket engine works by flowing liquid methane and oxygen into its turbopumps. The gases are pressurized, mixed, and heated in two preburners, with one receiving more methane and the other more oxygen. Both the high pressure and high temperature cause the liquids to evaporate, spinning the turbines and turbopumps by a shaft. This process repeats until the hot gas ignites in a combustion chamber. The resultant gas quickly moves, and the engine nozzle directs it to produce thrust. The engine is cooled by circulating the fuel around the outside of the fuel chamber, which also preheats the mixture.

Operation

Planned missions

Artist depiction of a large white lunar lander on the Moon, with the crews nearby

Artist depiction by SpaceX of Starship HLS offloading astronauts and cargo onto the lunar surface

SpaceX aims for Starship to replace its existing rockets, Falcon 9, Falcon Heavy, and Dragon 2 fleet. In November 2019, Musk estimated that a Starship launch might cost US$2 million, including US$900,000 of propellant. Starship could carry up to four hundred Starlink satellites into orbit, far more than the Falcon 9's 60.

On 14 September 2018, SpaceX's first private contract was announced by Japanese entrepreneur Yusaku Maezawa. He plans a private space tourism mission called the dearMoon project. The mission would perform a trans-lunar injection, circle the Moon, and return to Earth. As of October 2021, the mission's crew consists of Maezawa and ten to twelve others.

In October 2020, NASA provided US$53.2 million to SpaceX to demonstrate the transfer of 10 metric tons (9.8 long tons) of cryogenic propellant between two Starships.

On 16 April 2021, NASA selected Starship HLS and awarded SpaceX a US$2.89 billion contract over Integrated Lander Vehicle and Dynetics HLS. Starship HLS will perform an uncrewed landing demonstration and an Artemis 3 crewed lunar landing mission.

Space colonization

Main article: SpaceX Mars program

Artist depiction by SpaceX of ITS in close approach to Mars

SpaceX has stated that its goal is to kick-start Mars colonization and terraforming by its launch vehicles. Musk has stated that his goal is the long-term survival of the human species and to inspire legislators to fund spaceflight more. From 2011 to 2017, the company proposed a spacecraft to transport crew and cargo to Mars called Red Dragon, using a modified Dragon capsule. Musk estimated that a Mars city containing a million people would be self-sustaining, involving at least ten thousand crewed Starships and a hundred thousand Starships carrying cargo excluding local population growth.

The mission begins with cargo Starships that deliver requisite equipment to Mars' surface, including a fertilizer factory, a propellant factory, and construction materials for assembling geodesic domes to cover farmland. The propellant factory takes in carbon dioxide from Mars's atmosphere and hydrogen from underground ice. Afterward, the factory uses the Sabatier reaction to create liquid methane and liquid oxygen. The spacecraft can then return from Mars to Earth.

At the 67th International Astronautical Congress, Musk outlined that the Mars variant might carry cargo and 100 passengers to Mars. It might have 825 m³ (29,100 cu ft) of pressurized space, divided into forty cabins, storage space, a galley, a common area, and a solar storm shelter to protect against ionizing radiation. At that conference, Musk presented conceptual missions to destinations such as Enceladus, Europa, Pluto, and the Oort cloud that could launch from Mars.

Development

For further information, see [[:SpaceX Starship development history]]. For a list of test articles flights, see [[:List of SpaceX Starship launches]].

Design history

Artist depiction by SpaceX of Big Falcon Rocket in flight

The first reference by SpaceX of a rocket concept with Starship lifting capabilities was in 2005. In a student conference, Musk briefly mentioned a theoretical heavy‑lift launch vehicle code-named BFR, later known as the Falcon XX. It would be powered by a larger version of the Merlin engine, called Merlin 2, and feature a lifting capability of 140 metric tons (310,000 lb) to low Earth orbit. In 2012, in a public discussion about a conceptual Mars colonization program, Musk described the Mars Colonial Transporter. He envisioned it as a reusable super heavy-lift launch vehicle that could deliver approximately 150 to 200 metric tons (330,000 to 440,000 lb) to low Earth orbit. The Mars Colonial Transporter might be powered by Raptors, consuming liquid methane and liquid oxygen.

In September 2016, at the 67th International Astronautical Congress, Musk announced the Interplanetary Transport System (ITS), a conceptual reusable rocket conceived to launch humans to Mars and other destinations in the Solar System. The ITS was to be 122 m (400 ft) tall, 12 m (39 ft) wide, and capable of lifting 300 metric tons (660,000 lb) to low Earth orbit. Both stages were to be made from carbon composites. The first stage or booster was to be powered by 42 Raptors, and the second stage by nine Raptors. Once refueled while in Earth orbit, the spacecraft could accelerate to Mars. When an Interplanetary Spaceship enters the atmosphere, it cools itself via transpiration and controls the spacecraft's descent by moving its delta wings and split flaps. At the following Congress, Musk announced a replacement rocket called the Big Falcon Rocket or informally Big Fucking Rocket. The Big Falcon Rocket is 106 m (348 ft) tall and 9 m (30 ft) wide. In that conference, he talked about a possible suborbital transportation feature and termed it Earth to Earth.

In November 2018, the present names were first used: Super Heavy for the booster, Starship for the spacecraft, and Starship system or just Starship for the whole vehicle. Around that time, Musk announced a redesigned spacecraft concept with three aft flaps and two forward flaps. In January 2019, Musk announced that Starship would be made from stainless steel and stated that this might be stronger than an equivalent carbon composite in a wide range of temperatures. In March, Musk tweeted that SpaceX opted for a heat shield composed of hexagonal ceramic tiles instead of transpiration. In October, the Starship spacecraft's engine configuration was changed to three Raptors optimized for atmospheric pressure and three optimized for space. The number of rear fins was reduced from three to two and placed at the heat shield's edges.

Testing

A steel rocket stage hovering with an engine

SN5's hop at the Boca Chica launch site, firing a Raptor

The Boca Chica launch site is the primary facility for developing and testing Starship. Starship test articles must pass the ambient-temperature pressure test, cryogenic proof test, and static fire test. In detail:

• The ambient-temperature pressure test involves filling the stage's tanks with ambient pressure nitrogen gas to highlight leaks;
• The cryogenic proof test assesses the vessel's strength by loading and unloading liquid nitrogen; and
• A static fire test confirms the engines' readiness by loading propellant and firing the rocket engines.

Verified test articles will launch in different flight paths, depending on their objectives.

On 27 August 2019, a simplified test article named Starhopper hopped 150 m (490 ft) high. Unveiled in a SpaceX event in September 2019, Starship Mk1 (Mark 1) was the first full‑scale Starship test article to be built. The Mk2 in Florida was constructed five months later. Neither flew: Mk1 failed a cryogenic proof test and Mk2 was scrapped. In early 2020, SpaceX changed Mk3's name to SN1 (serial number 1). During a cryogenic proof test on 28 February 2021, a fault in SN1's bottom tank caused it to crumble. On 8 March 2020, SN2 stripped-down test tank completed its only cryogenic proof test. On 3 April 2020, during SN3's cryogenic proof test, a valve leaked the liquid nitrogen inside its lower tank, causing the vessel to depressurize and collapse. After SN4's fifth successful static fire test on 29 May 2020, the quick disconnect fuel line caused it to explode. On 15 June 2020, Musk tweeted that new prototypes would be made from SAE 304L instead of 301 stainless steel. On 4 August 2020, SN5 completed a 150 m (490 ft) hop using a single Raptor, the first full-scale test article to complete a flight test intact. On 24 August 2020, SN6 replicated SN5's flight path successfully. SN7 was not completed, but as of October 2021, its tanks were salvaged for various experiments.

SN8 was the first complete test article. In October and November 2020, SN8 underwent four static fire tests; the first, second, and fourth were successful, but the third caused an engine shutdown. According to Musk, the force from the engine destroyed parts of the launch pad sending some pieces of it into the engine. On 9 December 2020, SN8 performed the first flight by a Starship, reaching an altitude of 12.5 km (7.8 mi). During landing, its methane header tank did not provide sufficient fuel to the Raptors, reducing thrust from one engine. The test article exploded on impact. On 2 February 2021, SN9 flew 10 km (6.2 mi) high. While descending, one of its engines did not function and burst on landing at an angle. On 3 March 2021, SN10 repeated SN9's flight path, then hard landed and set off itself 8 minutes later.

A steel rocket firing its engine with an orange plume

Liftoff of SN15 at the Boca Chica launch site, firing three Raptors

The first Super Heavy booster named BN1 (booster number 1) finished construction on 8 March 2021, but it had not received engines. On 30 March 2021, SN11 exploded in midair without a confirmed explanation because of the dense fog at the launch site. A possible explanation is that an engine might have burned the test article's avionics and could have caused a hard start on the engine's turbopump. After the launch, SpaceX skipped SN12, SN13, SN14, and BN2, and incorporated obsolete test articles' improvements to SN15 instead. On 5 May 2021, the test article flew the same flight path as previous test articles and soft landed successfully. On 20 July 2021, BN3 fired its engines for the only time. As of October 2021, SN15, SN16, and BN3 had been retired and displayed.

As of October 2021, skipping over SN16, SN17, SN18, and SN19, SN20 along with BN4 are targeted to an orbital flight scheduled for late 2021. However, a NASA public document that outlines NASA's plan to observe Starship's reentry inferred that the launch might happen near March 2022. The Federal Aviation Administration (FAA) has not approved the environmental impact statement draft released on 19 September 2021. The rocket is planned to head toward the middle of the Straits of Florida. BN4 is expected to separate about three minutes into the orbital flight and splashdown in the Gulf of Mexico, approximately 30 km (19 mi) from the shoreline. SN20 is then expected to accelerate close to orbital speed, then splashdown ninety minutes later about 100 km (60 mi) northwest of Kauai.

• Pictures of Starship test articles
• 
  Starship Mk1's nose cone near construction tents
• 
  Starhopper in construction
• 
  A crane lifting Starship SN5
• 
  Starship SN7's tank
• 
  Starship SN9 on the launchpad
• 
  A worker is examining Starship SN20's ceramic tiles

Test articles timeline

See also: List of SpaceX Starship test articles

Note: The start dates are when the test articles were first spotted by the public, and the end dates are when the test articles are destroyed, decommissioned, or retired.Template:Starship Timeline

Criticism and controversies

Starship SN8 remains after it crashed to the ground

Some residents of Boca Chica Village, Brownsville, and environmental activists criticized the Starship development program, stating that SpaceX had harmed local wildlife, conducted unauthorized test flights along with infrastructure construction, and polluted the area with noise. Environmental groups warned that the program threatens wildlife in the area, including 18 vulnerable and endangered species. David Newstead, the director of one local environmental group, complained that the explosion of SN11 left rocket debris on parts of the wildlife refuge that took three months to clean up.

The United States Fish and Wildlife Service claimed that SpaceX had caused 1,000 hours of highway closures in 2019, well above the permitted 300 hours. In June 2021, Cameron County District Attorney Luis Saenz threatened to prosecute SpaceX for unauthorized road and beach closures, as well as employing security officers who may not be licensed to carry handguns.

During the SN8 launch, SpaceX ignored FAA warnings that the flight profile posed a risk of explosion. Following the launch, the FAA's Associate Administrator Wayne Monteith commented that SpaceX does not has a strong safety culture for not conducting thorough checks and following the FAA's statements. Members of the United States Congress voiced concerns about the FAA's response, calling on the agency to not over-influence SpaceX.

As of October 2021, the FAA was allowing the public to comment until 1 November on the environmental impact statement draft, released on 19 September. Experts commented that SpaceX's environmental assessment was missing important details about where its fuel will come from. One such example is SpaceX's plan of building a 250-megawatt gas-fired power plant without specifying how it would obtain sufficient fuel (tens of millions of cubic feet of gas per day). Pat Parenteau, a law professor and senior counsel for the Environmental Advocacy Clinic at Vermont Law School, stated that it was unusual to exclude such details, which could violate the U.S. National Environmental Policy Act.

External links

• Media related to Starship at Wikimedia Commons
• Starship's official website by SpaceX