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Starship is a fully reusable launch vehicle in development by American aerospace company SpaceX. The launch vehicle consists of a reusable Super Heavy booster and Starship spacecraft. Both are made from stainless steel and hold liquid oxygen with liquid methane use by the Raptor rocket engines. Starship's large payload capacity to space and full reusability should make it both extremely cost-competitive and able to serve many facets of spaceflight, including space tourism, interplanetary spaceflight, and fast point-to-point flights between places on Earth. With these capabilities, the rocket is incorporated into many space missions, such as the dearMoon project, NASA's Artemis program, and SpaceX's Mars program.
Starship was called the Mars Colonial Transporter, Big Falcon Rocket, and Interplanetary Transport System, each with different designs. On 25 July 2019, Starhopper performed the first successful flight by any Starship test article at the South Texas launch site. The first complete Starship test article was SN8, which crashed upon landing on 9 December 2020 and has raised many concerns about SpaceX's safety procedures on testing and damages to the surrounding environment. As of October 2021, Super Heavy BN4 and Starship SN20 were expected to become the first test article to attempt launch to orbit.
Background
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Although a large-scale, self-sufficient, and developed space economy is the aim of the industry, the extreme cost of accessing space has been a barrier to achieving the goal. Little market competition emerged inside any national market, and within the United States, high cost and preference in existing contractors made commercial launch service providers difficult to compete. However, many measures of cost reduction had been implemented by various agencies and companies with varying success. One example is the development of small-lift launch vehicles, which in 2008 the United States Air Force expected launch cost to be less than ten million United States dollars ($).
In the early 2010s, private spaceflight emerged and brought substantial competition into the existing market, which notable space vehicles of the sector include the Falcon 9, Electron, and the LauncherOne. Also at the time, there have been numerous concepts and proposals of human mission to Mars, however, none of them made it to the technology development phase.
SpaceX recovered first stages of several early Falcon 9 flights to assist engineers making the rocket stage's reusable. At first, both stages were equipped with parachutes, but the mechanism failed to survive extreme heat during atmospheric re-entry. By late 2014, SpaceX replace the parachutes with directly using the first stage's engines to propulsively land and abandon the idea of reusing Falcon 9's second stage. Technology developed for second stage reuse were then transferred to Starship's development.
Current design
The goal of the Starship launch vehicle is to be a fully reusable orbital launch and reentry vehicle. It is 120 m (390 ft) high and has a 9 m (30 ft) diameter, taller than the Saturn V also by 9 m (30 ft). Starship consists of two stages: a Super Heavy booster and a Starship spacecraft; both have a body made from SAE 304L stainless steel. Starship and Super Heavy are also powered by Raptor and Raptor Vacuum engines, consuming liquid oxygen and methane.
A Starship launch can deliver more than 100 t (220,000 lb) to low Earth orbit, and higher Earth, Moon, Mars, and other orbits can be accessed after the spacecraft is refueled by tanker Starships. Starship is an integral component of the envisioned SpaceX's Mars program, which should start the planet's exploration and hypothetical colonization. Its design has influenced other launch vehicles, such as the Terran R's full reusability capability.
Raptor engine
Both Starship's stages are equipped with Raptor engines, full-flow staged combustion cycle rocket engines consuming liquid methane and oxygen. In an interview with Tim Dodd, Musk stated that Raptors would combust liquid oxygen to liquid methane in a ratio of 3.5 to 3.7. For the Raptor Vacuum variant, it is equipped with nozzle extension with a throat area to exit area of 1 to 80 to increase Raptor's specific impulse in space to about 380 s (3.73 km/s). Later Starships might be equipped with an improved version of Raptor called Raptor 2. In the same interview, Musk also mentioned that most of the original Raptor variant will be produced in a new SpaceX facility in McGregor, while SpaceX's factory at Hawthorne would be used to produce Raptor Vacuum and test new engine design.
Super Heavy booster
The booster is 70 m (230 ft) tall and may house up to 33 sea-level optimized Raptor engines. Its tanks can hold about 3,600 t (7,900,000 lb) of propellant, consisting of about 2,800 t (6,200,000 lb) of liquid oxygen and 800 t (1,800,000 lb) of liquid methane. Without propellant, the booster might weigh from 160 t (350,000 lb) to 200 t (440,000 lb).
Four grid fins are installed above the booster and controlled by electric motors; these grid fins are used to 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 change the booster's pitch easier. 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 use evaporated gas from the propellant tanks to control the booster's attitude during flight, as well as exploit the Coriolis effect to separate from the spacecraft.
Starship spacecraft
The Starship spacecraft is attached to the top of the Super Heavy booster, 50 m (160 ft) tall, and can hold 1,200 t (2,600,000 lb) of propellant. The closest estimation of Starship's dry mass from Elon Musk is less than 100 t (220,000 lb). Six Raptors are connected at spacecraft's bottom, three are optimized for atmospheric pressure, and three for vacuum operation.
Starship also has four body flaps to control falling velocity and vehicle's orientation, two are mounted at the nose cone and called aft flaps, and two are mounted near the bottom and called front flaps. Its heat shield should be able to use multiple times with little maintenance in-between. SpaceX think Starship would be reliable by the time it is crewed, so it does not have a launch escape system.
SpaceX plans to build multiple Starship variants. For the cargo variant, 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.
Starship Human Landing System (Starship HLS), a variant of Starship, will serve as a crewed lunar lander for NASA's Artemis program. It does not need a heat shield or body flaps since it will not enter back to Earth's atmosphere, and accompanying are Starship tankers transferring propellant in orbit to Starship propellant depot variant, where it stores propellant to fuel the lunar lander. It is expected that SpaceX will demonstrate transferring 10 t (22,000 lb) of propellant between two Starships for NASA.
Another Starship variant could deliver passengers on point-to-point flights, termed Earth to Earth by SpaceX. The craft would travel between spaceports, with flight times of some 40 minutes from New York City to Shanghai. Its president Gwynne Shotwell predicted that it could be cost-competitive with business class travel. UBS predicted that point-to-point travel market would worth $20 billion in 2030 and would directly compete with airline travel.
Operation
Ground infrastructure
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The Starship's launch tower consists of steel truss sections and a lightning rod on top, with a pair of mechanical arms and a large crane. The crane lifts and stabilizes the rocket on the launch table, while the launch tower recovers Super Heavy by catching with the mechanical arms, nicknamed Mechazilla by Musk. Eventually, this recovery system might make these rocket stages to be prepared quickly and allow multiple launches in a day.
Starship may launch at SpaceX's South Texas launch site, offshore platforms, and Kennedy Space Center Launch Complex 39A (LC-39A). The South Texas launch site is also referred to by SpaceX as Starbase. The offshore platforms, named Phobos and Deimos after the moons of Mars, were former oil drilling rigs named Valaris 8500 and 8501. Both spaceports are 78 m (260 ft) long and 73 m (240 ft) wide; each is also equipped with two Seatrax S90 cranes.
These infrastructures are the subject of many spaceflight news correspondents and enthusiasts. However, some residents of the Boca Chica Village and Brownsville criticized the Starship development program, claiming that SpaceX had conducted unauthorized test flights along with infrastructure construction, force sale of houses, and noise pollusion. Environmental groups claimed that the program threatens surrounding wildlife, including eighteen endangered species.
Economics and missions
As Starship will be more capable and less expensive to launch, it is aimed to replace all SpaceX's existing launch vehicles and spacecraft, including the Falcon 9, Falcon Heavy, and Dragon 2. For example, while a Falcon 9 launch can deliver sixty Starlink satellites to low Earth orbit, Starship would be able to put four hundred of them to the same destination.
While Starship launch cost estimates vary widely, in November 2019, Musk estimated that a launch might cost $2 million, with $900,000 for propellant. It is expected with a larger volume and mass capacity, as well as substantially lower cost per kilogram to orbit, Starship may allow larger and more advanced science payloads such as the 15.1 m (49.5 ft) mirror diameter variant of the Large Ultraviolet Optical Infrared Surveyor space telescope.
Another potential for Starship is space tourism, where a space mission named dearMoon project has been planned by Japanese entrepreneur Yusaku Maezawa. Originally using a Crew Dragon capsule, the dearMoon project plans to perform a flight around the Moon with Starship. The mission's crew is expected to consist of Maezawa and eight others from the public.
Starship might transport cargo anywhere on Earth in under 1 hour on point-to-point flights. As of October 2020, the Rocket Cargo program is the only dedicated program that research this mode of transport, funded by United States Transportation Command. Although the specific launch vehicle is not disclosed, many news media speculated that Starship is the most possible launch vehicle mentioned for the program, the only space vehicle with these capability.
On 16 April 2021, NASA selected Starship HLS and awarded SpaceX a $2.89 billion contract over the Integrated Lander Vehicle and Dynetics HLS, where Starship HLS will need to perform an uncrewed landing demonstration before it would do a crewed lunar landing on the Artemis 3 flight. However, responding to the announcement, Blue Origin on 26 April 2021 filed a protest with the Government Accountability Office, and on 4 November 2021, the United States Court of Federal Claims gives a memorandum opinion titled Blue Origin v. United States & Space Exploration Technologies Corp. rejecting Blue Origin's complaint.
Space colonization
SpaceX has stated that its goal is to start the colonization of Mars and terraforming by its launch vehicles, for the long-term survival of the human species. Musk had estimated that a Mars city containing a million people would be self-sustaining, meaning excluding population growth, at least ten thousand crewed Starships and a hundred thousand Starships delivering cargo is needed.
Starship can use the Sabatier reaction to create liquid methane and liquid oxygen on Mars, by exposing carbon dioxide and hydrogen to a catalyst and temperature conditions of 300–400 °C (600–800 °F) and pressure conditions of 3 MPa (400 psi). Carbon dioxide and hydrogen gas can be obtained from Mars's atmosphere and underground ice. The Sabatier reaction is an endothermic reaction with a chemical formula below:
- CO2 (g) + 4 H2 (g) → CH4 (g) + 2 H2O (g) (ΔHr = −165.0 kJ/mol)
Development
Earlier designs
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In November 2005, SpaceX first referenced a launch vehicle concept with Starship's capabilities, when in a student conference, Musk briefly mentioned a theoretical heavy‑lift launch vehicle code-named BFR. It was going to be powered by a larger version of the Merlin engine called the Merlin 2. At least from 2012, SpaceX has thought about building another space vehicle called the Mars Colonial Transporter, but little information is given to the public.
In September 2016 at the 67th International Astronautical Congress, Musk announced the renamed the Mars Colonial Transporter called Interplanetary Transport System, as well as provided key information about it to the public. The Interplanetary Transport System was to be 122 m (400 ft) tall, 12 m (39 ft) wide, and conceived to be a fully reusable launch vehicle that could launch humans to Mars and other destinations in the Solar System.
Both stages were to be made from carbon composites, with the first stage or booster was to be powered by 42 Raptor engines, and the second stage or spacecraft named Interplanetary Spaceship was to be powered by nine Raptor engines. These Raptor engines are used not only for thrusting the launch vehicle to orbit, but also enable these rocket stages to propulsively land to the surface. The second stage was going to have a PICA heat shield to protect itself when enters the atmosphere as well as could be fueled in orbit to be able to reach further destinations in the Solar System.
At the following International Astronautical Congress, Musk announced a replacement launch vehicle called the Big Falcon Rocket or informally called the Big Fucking Rocket. The Big Falcon Rocket was revised to be 106 m (348 ft) tall and 9 m (30 ft) wide, with three aft flaps and two forward flaps to control its descent. Other than updated rocket engine arrangement, most features of this launch vehicle are largely equivalent to the Interplanetary Transport System. In that conference, he talked about a possible point-to-point transportation feature and termed it Earth to Earth. In November 2018, the present names of the launch vehicle and stage were first published: Super Heavy for the booster, Starship for the spacecraft, and Starship for the whole vehicle.
Starhopper–SN7: Hops
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 the same month, SpaceX announced it would lay off ten percent of its workforce to help finance Starship and Starlink projects. On 27 August 2019, a simplified test article named Starhopper hopped 150 m (490 ft) high. Starship Mk1 (Mark 1) was the first full‑scale Starship test article built in September 2019 and Mk2 was constructed five months later in Florida. Both test articles could not fly and were recycled years later.
During a cryogenic proof test on 28 February 2021, SN1 (Mk3) crumbled due to a fault in its bottom tank. 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 test article also exploded. A month later, Musk tweeted that new prototypes would be made from SAE 304L instead of SAE 301 stainless steel. On 4 August 2020, SN5 completed a 150 m (490 ft) hop using a single Raptor engine, and SN6 replicated SN5's flight path successfully 20 days later.
SN8–SN19: Flights
SN8 was the first complete Starship test article and underwent four static fire tests between October and November 2020. Notably, in the third static fire test, the engine might melt the launch pad and bits of molten concrete hit it back. On 9 December 2020, SN8 performed the first flight by a Starship, reaching an altitude of 12.5 km (7.8 mi), and crashed on impact. During the SN8 launch, SpaceX ignored Federal Aviation Administration (FAA) warnings that the flight profile posed a risk of explosion, causing the FAA's Associate Administrator Wayne Monteith to condemn the company for not conducting thorough checks established by the agency.On 2 February 2021, SN9 flew 10 km (6.2 mi) high, then crashed at an angle. On 3 March 2021, SN10 repeated SN9's flight path and successfully hard landed. However, it exploded 8 minutes later. On 30 March 2021, SN11 exploded in a dense fog while descending, with the most possible explanation is a hard start on the engine's turbopump. After the launch, SpaceX skipped SN12, SN13, and SN14, incorporating their improvements to SN15 instead. On 5 May 2021, the test article flew the same flight path as previous test articles and soft-landed successfully.
SN20–present: Orbital launches
As of October 2021, skipping over SN16, SN17, SN18, and SN19, SN20 along with BN4 are targeted to an orbital flight near March 2022. 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 spacecraft's ground track will then traverse the middle of the Straits of Florida. Once over the Atlantic Ocean, SN20 is then expected to accelerate close to the orbital speed and splashdown around ninety minutes later 100 km (60 mi) northwest of Kauai, Hawaii. The FAA allowed the public to comment until 1 November on the environmental impact statement draft released on 19 September, which many experts criticized it for missing important details about the propellant source.
