SpaceX Starship (spacecraft). {{Infobox spacecraft class
| name = Starship
| image = Starship S20.jpg
| image_caption = Starship prototype SN20 at the launch site; the distinctive stainless steel structure is visible as well as the edges of the dark thermal protection tiles that cover the other side of the vehicle.
| manufacturer = SpaceX
| country = United States
| operator = SpaceX
| applications = 
| website = 
| spacecraft_type = Crewed, reusable
| payload_capacity =  (planned)
| crew_capacity = Up to 100 (planned)
| volume =  (planned)
| winged = yes
| span = 
| status = In development
| launched = 
| retired = 3
| failed = 
| lost = 
| firstlaunch = 20 April 2023
| derivatives = Starship HLS
| flown_with = SpaceX Super Heavy
| stagedata = 
  

}}
Starship is a spacecraft and second stage under development by American aerospace company SpaceX. Stacked atop its booster, the Super Heavy, the pair compose SpaceX's super heavy-lift space vehicle, also called Starship. The spacecraft is designed to transport both crew and cargo to a variety of destinations, including Earth orbit, the Moon, and Mars. It's designed to be reusable and capable of landing propulsively by firing its engines to perform a controlled descent in the arms of a tower on Earth or with landing legs on other planetary bodies. It is intended to enable long duration interplanetary flights with a crew of up to 100 people. It will also be capable of point-to-point transport on Earth, enabling travel to anywhere in the world in less than an hour. Furthermore, it will be used to refuel other Starship spacecraft, enabling them to reach higher orbits and other space destinations. Elon Musk, the CEO of SpaceX, estimated in a tweet that eight launches would be needed to completely refuel a Starship in low Earth orbit, enabling it to travel onwards.

Development began in 2012, when Musk described a plan to build a reusable launch vehicle with substantially greater capabilities than the Falcon 9 and the planned Falcon Heavy. The rocket evolved through many design and name changes. On July 25, 2019, the Starhopper prototype performed the first successful flight at SpaceX Starbase near Boca Chica, Texas. In May 2021, the SN15 prototype became the first full-size test spacecraft to take off and land successfully. On April 20, 2023, Starship 24 performed the first full flight test on top of a Super Heavy booster, followed by a second test on November 18, 2023, when Starship 25 successfully completed hot-staging and passed the Kármán Line, becoming the first Starship to reach space as well as the heaviest object to ever reach space, before exploding at 148 km. As of November 2024, SpaceX has conducted 4 more flight tests of Starship, successfully achieving orbital velocities and gradually testing the atmospheric reentry and vertical landing capabilities of the vehicle by performing controlled splashdowns into the Indian Ocean. In April 2024, Elon Musk announced two new versions of Starship, Block 2 and Block 3. Both versions will be taller and will have increased thrust.

Design 
The Block 2 version of Starship is  tall,  wide, and is composed of four general sections: the engine bay, the oxygen tank, the fuel tank, and the payload bay. The retired Block 1 was constructed in a similar manner, though it was only  tall. Elon Musk stated in 2021 that the vehicle has a dry mass of roughly . The windward side is protected by a heat shield, which is composed of eighteen thousand hexagonal black tiles that can withstand temperatures of . It is designed to protect the vehicle during atmospheric entry and to be used multiple times with minimal maintenance between flights. The silica-based tiles are attached to Starship with pins, and have small gaps in between to allow for heat expansion. After IFT-4, SpaceX added a secondary ablative layer under the primary heat shield, though this was only added to the flaps of the IFT-6 vehicle. This ablative layer is likely composed of pyron, which is similar in composition to carbon composites. The total mass of the heat shield and ablative layer of a Block 1 ship is .

Tanks 
The propellant tanks on Starship are separated by a common bulkhead, similar to the ones used on the S-II and S-IVB stages on the Saturn V rocket. While Block 2 vehicles use an elliptical dome, the common and forward domes of the Block 1 design were more conical. Both tanks are heavily reinforced, with roughly 30 and 48 stringers attached to the interior walls of the methane and oxygen tanks, respectively. Block 1 vehicles lacked any reinforcement to the methane tank, and the oxygen tank only had 24 stringers. The vehicle's tanks hold  of propellant, consisting of  of liquid oxygen and  of liquid methane. Running along the sides of the tanks are the "raceways", which support the transfer of pressurization gas and electricity throughout the vehicle. Beginning with Block 2 vehicles, these are covered by dedicated aerocovers.

The methane tank has a camera installed in the forward dome, enabling images of the interior of the tank. There are three baffles located inside the tank to prevent sloshing of the propellant during flight. Fuel is fed to the engines via four downcomers, with three smaller downcomers feeding the Vacuum Raptors/RVacs and the central downcomer feeding the inner three engines. The central downcomer connects to a large sump, instead of directly to the methane tank itself. The original design only featured a single downcomer, which terminated in a distribution manifold, directing propellant to the three sea level engines and the individual RVacs. Inside this tank are two additional downcomers, which provide oxygen and methane to the central three engines from the header tanks. The LOX downcomer extends into the LOX tank, with a small expanded portion of unknown purpose. A camera is located on the walls of the tank, near the flight termination system.

Like the methane tank, the oxygen tank also has three baffles to prevent sloshing. The oxygen tank terminates with the thrust structure of the vehicle. The RVacs are mounted directly to the aft dome, which has reinforcements mounted inside of the tank. The three sea level engines are mounted on the thrust puck, which forms the bottom of the aft dome. A conical steel structure is mounted inside the bottom of the dome, reinforcing the thrust puck enough to enable its support of the inner three engines, while also providing pathways for methane and oxygen to flow into the engines. The outer wall of the aft dome is covered in an insulation material, presumably to prevent frost from building up inside the engine bay during propellant load.

The propellant lines on the vehicles are all vacuum jacketed, reducing boiloff while in orbit. Block 1 vehicles used more conventional insulation, though only on the header tank's propellant lines.

Propulsion 
Starship is powered by 6 Raptor engines, which are housed within a dedicated shielding compartment. This compartment is present before engine installation, and contains several critical systems. These includes some of the motors for the aft flaps, the quick disconnect interface, and at least one battery. A camera is mounted inside of this bay, enabling images of the engines during flight. Until Starship flight test 3, this section held the hydraulic power unit, which provided the three sea level engines with thrust vector control capability. The first Block 1 vehicle, S20, had multiple composite overwrapped pressure vessels (COPVs) mounted in this region as well. These components are all protected by the engine shielding.

The 3 Rvacs, which are arranged in a single ring, are in a fixed position. An additional three RVacs will be added to the Block 3 ship design. The inner three engines are attached to an adapter, which rests directly against the thrust puck/aft dome assembly. These engines are equipped with gimbal actuators, and reignite for the landing burns. After Starship's second flight test, this gimbaling system was switched from a hydraulic system to an electric one, enabling the removal of the hydraulic power units. This change was made to the booster after the first flight test. During the ascent burn burns, the engines draw propellant from the main tanks, with all subsequent burns drawing propellant from dedicated header tanks. 

The engine shielding, which isolates individual engines in the event of a failure, was upgraded after Starship's first flight test, alongside the fire suppression system. This system uses  tanks to purge the individual engine compartments during flight, as well as a nitrogen purge while on the launch pad. There are ten vents in the aft bay for preventing an overpressure in the engine shielding compartment. Beginning with S25, the Block 1 design had between 14 and 16 such vents.

The Raptor engine uses a full-flow staged combustion cycle, which has both oxygen and methane-rich turbopumps. Before 2014, only two full-flow staged-combustion rocket engine designs had advanced enough to undergo testing: the Soviet RD-270 project in the 1960s and the Aerojet Rocketdyne Integrated Powerhead Demonstrator in the mid-2000s. To improve performance, the engines burn super cooled propellant.

The Block 1 version of the ship (used through November 2024) produces a total of  almost triple the thrust of the Saturn V second stage, with this total being expected to increase to  for Block 2 boosters and later up to  with the Block 3 vehicle.

During unpowered flight in orbit, control authority is provided by cold gas thrusters fed with residual ullage gas. Four of these thrusters are located on the methane tank. Another four are located just below the payload bay, and two on the oxygen tank. Near the top of the nosecone, there are four vents connected to the header tanks, as well as two others located on the tip of the payload bay. In the aft bay, two engine chill lines double as thrusters near the base of the vehicle. Finally, three large liquid oxygen  (LOX) vents are located in the aft bay of the vehicle, enabling the ship to dump LOX as needed. For Block 1 ships, these vents terminated in a singular large nozzle, with Block 2 vehicles, each vent splits into two smaller nozzles.

Payload bay 
The payload bay hosts the nosecone, header tanks, forward flaps, multiple COPVs, and the "pez dispenser". The header tanks provide propellant for all burns after SECO, and are mounted at the tip of the payload bay. These tanks only connect to the sea level engines. The LOX header tank forms the top of the nosecone, with the methane header tank attached directly below it. These tanks terminate in a conical sump, which are attached to the downcomers. Block 1 vehicles lacked this sump, reducing propellant capacity. Fourteen COPV's are mounted in the space around the methane header tank, providing the startup gas for the engines, as well as six near the pez dispenser.

The nosecone has substantial internal reinforcement, mainly around the forward flap attachment points and lifting points for the chopsticks. The number of internal stringers was increased between Block 1 and Block 2 vehicles. Additional reinforcements are used to support the pez dispenser on ships equipped with one. Located along the sides of the nosecone are two Starlink antennas. Another two are placed at the bottom of the payload bay. These allow communication with the ship during reenty.

The pez dispenser is used to deploy Starlink satellites into LEO. It was first added to S24, though it was permanently sealed until flight 3. It consists of the dispenser mechanism and the door. The door is actuated, folding up into the payload bay to open, and lowering to close. Its approximately  tall and  wide. In order to account for the door, significant structural reinforcements are added around it. During assembly, additional reinforcements are added to the door. The door has substantial reinforcements added to its interior, helping prevent deformation. The door is capable of maintaining a seal during flight, so long as it is not opened.

The dispenser itself is mounted directly to the forward dome. It has a truss structure for its base, with solid steel used elsewhere. A mobile track is used in the base, enabling the dispenser to push the satellite out of the vehicle. After dispensing a satellite, the next payload is lowered onto the base, and is deployed. The opposite occurs during loading, with the dispenser raising its payloads to receive another satellite. In order to prevent the satellite from floating out of the mechanism during zero-g operations, the dispenser locks the satellites in position using a "retention frame". This is lowered alongside the satellites during operation. On Block 1 vehicles, beginning with S24, the dispenser was made from stainless steel, with SpaceX potentially changing this to aluminum on Block 2.

Flaps 

Starship controls its reentry with four flaps, two aft flaps mounted to the sides of the engine bay and LOX tank and two forward flaps on the payload bay. Significant structural reinforcement is added to the flap attachement point and within the flaps themselves. According to SpaceX, the flaps replace the need for wings or tailplane, reduce the fuel needed for landing, and allow landing at destinations in the Solar System where runways do not exist (for example, Mars). The flap's hinges are sealed in aerocovers because they would otherwise be easily damaged during reentry.

Despite this, damage to the forward flaps was observed on flights four, five, and six, with near complete loss occurring on flight 4. Beginning with Block 2, the design of these forward flaps was significantly changed, becoming thinner and angled. This sets them at an approximately 140 degree angle between the forward flaps, compared to the 180 degrees of the aft flaps. On Block 1 vehicles, the forward flaps were also parallel to each other. This change was made to prevent the damage observed on the last three flights of the Block 1 ship. There are two cameras located at the bottom of the flaps, with another providing images of the flap itself. Both sets of flaps feature cameras in their hinges as well. All four flaps have small static wicks, which enable the vehicle to discharge static electricity in flight.

Variants 

For a non-Starlink satellite launch, Starship is planned to have a large cargo door that opens to release payloads, similar to NASA's Space Shuttle, and close upon reentry instead of a jettisonable nosecone fairing. Instead of a cleanroom, payloads are integrated directly into Starship's payload bay, which requires purging the payload bay with temperature-controlled ISO class 8 clean air.

Crewed Starship vehicles would replace the cargo bay with a pressurized crew section and have a life-support system. For long-duration missions, such as crewed flights to Mars, SpaceX describes the interior as potentially including "private cabins, large communal areas, centralized storage, solar storm shelters, and a viewing gallery". Starship's life support system is expected to recycle resources such as air and water from waste.

Starship will be able to refuel by docking with separately launched Starship propellant tanker spacecraft in orbit. Doing so increases the spacecraft's mass capacity and allows it to reach higher-energy targets, such as geosynchronous orbit, the Moon, and Mars. A Starship propellant depot could cache methane and oxygen on-orbit and be used by Starship to replenish its fuel tanks.

Starship Human Landing System (HLS) is a crewed lunar lander variant of the Starship vehicle that would be modified for landing, operation, and takeoff from the lunar surface. It features landing legs, a body-mounted solar array, a set of thrusters mounted mid-body to assist with final landing and takeoff, two airlocks, and an elevator to lower crew and cargo onto the lunar surface.

Varying estimates have been given about the number of tanker launches required to fully fuel HLS, ranging from between "four and eight" to a number "in the high teens". These launches will reportedly have to be in "rapid succession" in order to manage schedule constraints and cryogenic fuel boil-off. When fully fueled, Starship HLS is designed to land  of payload on the Moon.

History

Early concepts

Mars Colonial Transporter 
In October 2012, the company made the first public articulation of plans to develop a fully reusable rocket system with substantially greater capabilities than SpaceX's existing Falcon 9. Later in 2012, the company first mentioned the Mars Colonial Transporter rocket concept in public. It was to be able to carry 100 people or  of cargo to Mars and would be powered by methane-fueled Raptor engines. Musk referred to this new launch vehicle under the unspecified acronym "MCT", revealed to stand for "Mars Colonial Transporter" in 2013, which would serve as part of the company's Mars system architecture. SpaceX COO Gwynne Shotwell gave a potential payload range between 150 and 200 tons to low Earth orbit for the planned rocket. According to SpaceX engine development head Tom Mueller, SpaceX could use nine Raptor engines on a single MCT booster or spacecraft. The preliminary design would be at least  in diameter, and was expected to have up to three cores totaling at least 27 booster engines.

Interplanetary Transport System 
In 2016, the name of the Mars Colonial Transporter system was changed to the Interplanetary Transport System (ITS), due to the vehicle being capable of other destinations. Additionally, Elon Musk provided more details about the space mission architecture, launch vehicle, spacecraft, and Raptor engines. The first test firing of a Raptor engine on a test stand took place in September 2016.
The ITS second stage was planned to be used for long-duration spaceflight, instead of solely being used for reaching orbit. The two proposed variants aimed to be reusable. Its maximum width would be , with three sea level Raptor engines, and six optimized for vacuum firing. Total engine thrust in a vacuum was to be about . It would have  of propellant, and a dry mass of 150 tonnes (330,000 lb).

Big Falcon Rocket 
In September 2017, at the 68th annual meeting of the International Astronautical Congress, Musk announced a new launch vehicle calling it the BFR, again changing the name, though stating that the name was temporary. The acronym was alternatively stated as standing for Big Falcon Rocket or Big Fucking Rocket, a tongue-in-cheek reference to the BFG from the Doom video game series.

The BFR was designed to be  tall,  in diameter, and made of carbon composites. The upper stage, known as Big Falcon Ship (BFS), included a small delta wing at the rear end with split flaps for pitch and roll control. The delta wing and split flaps were said to expand the flight envelope to allow the ship to land in a variety of atmospheric densities (vacuum, thin, or heavy atmosphere) with a wide range of payloads. The BFS design originally had six Raptor engines, with four vacuum and two sea-level. By late 2017, SpaceX added a third sea-level engine (totaling 7) to allow greater Earth-to-Earth payload landings and still ensure capability if one of the engines fails.

Starship 
In December 2018, the structural material was changed from carbon composites to stainless steel, marking the transition from early design concepts of the Starship. Musk cited numerous reasons for the design change; low cost and ease of manufacture, increased strength of stainless steel at cryogenic temperatures, as well as its ability to withstand high heat. The windward side would be cooled during entry by allowing fuel or water to bleed through micropores in a double-wall stainless steel skin, removing heat by evaporation. The liquid-cooled windward side was changed in 2019 to use reusable heat shield tiles similar to those of the Space Shuttle.

In 2019, SpaceX began to refer to the entire vehicle as Starship, with the second stage being called Starship and the booster Super Heavy.

Initial testing 
The first tests started with the construction of the first prototype in 2018, Starhopper, which performed several static fires and two successful low-altitude flights in 2019. In June 2020, SpaceX started constructing a launch pad for orbital Starship flights. In August and September 2020, SN5 and SN6 conducted a  hop test. This was followed by a  flight test in December 2020, using SN8. Despite a full successfully ascent burn, SN8 failed durign the landing attempt, due to low methane header tank pressure.On February 2, 2021, Starship SN9 launched to  in a flight path similar to SN8. The prototype crashed upon landing because one engine did not ignite properly. A month later, on March 3, Starship SN10 launched on the same flight path as SN9. The vehicle landed hard and crushed its landing legs, and detonated ten minutes later. On March 30, Starship SN11 flew into thick fog along the same flight path. The vehicle exploded during descent, possibly due to excess propellant in a Raptor's methane turbopump. On May 5, 2021, SN15 launched, completed the same maneuvers as older prototypes, and landed safely. SN15 had a fire in the engine area after landing but it was extinguished.

Integrated flight tests 
Booster 7 and Ship 24 conducted several static fire and spin prime tests before launch, with the first such test doing significant damage to Booster 7 on July 11, 2022. After a launch attempt aborted on April 17, 2023, Booster 7 and Ship 24 lifted off on 20 April at 13:33 UTC in the first orbital flight test, with the vehicle being destroyed before stage separation.
On November 18, 2023, Booster 9 and Ship 25 lifted off the pad. After a successful stage separation, the second stage continued its ascent until it reached an altitude of ~, before the flight termination system activated, and destroyed the vehicle. It appeared to re-enter a few hundred miles north of the Virgin Islands, according to NOAA weather radar data.

Flight 3 launched from the SpaceX Starbase facility along the South Texas coast around 8:25 CDT on March 14, 2024, coincidentally the 22nd anniversary of its founding. After stage separation, the Starship vehicle reached orbital velocity. While on an almost-orbital trajectory, the vehicle conducted several tests after engine cutoff, including initiating a propellant transfer demo and payload dispenser test. It attempted to re-enter the atmosphere, and at an altitude of around , all telemetry from Ship 28 stopped, indicating a loss of the vehicle.

The fourth flight test of the full Starship configuration launched on June 6, 2024, at 7:50 AM CDT. The goals for the test flight were for the ship to survive peak heating during atmospheric reentry. The ship survived atmospheric reentry and successfully ignited its engines for a controlled splashdown.

Flight 6 was flown on November 19, 2024, successfully relighting a Raptor engine in the vacuum of space, paving the way for payload deployments on future flights. A stuffed toy banana served as the zero-g indicator, becoming Starship's first payload, though it remained within the vehicle for the duration of the flight. Eric Berger claimed that, due to the success of the in-space relight, Starship would likely be "cleared to travel into orbit".

See also 
 SpaceX Super Heavy
 Artemis Program
 New Glenn
 Falcon Heavy
 Private spaceflight
 Space Shuttle orbiter
 Timeline of space exploration

Notes

References 

Proposed reusable launch systems
Reusable spaceflight technology
Reusable spacecraft
Rocket stages
SpaceX Starship
SpaceX spacecraft