SpaceX

SpaceX was founded in 2002 by entrepreneur Elon Musk with the goal of reducing space transportation costs and enabling the colonization of Mars. SpaceX has since developed the Falcon launch vehicle family and the Dragon spacecraft family, which both currently deliver payloads into Earth's orbit. SpaceX was formed, in part, with the idea of making affordable spaceflight a reality.

The Dragon resupply mission represented the first re-flight of a commercial spacecraft to and from the International Space Station (ISS). In 2012, the Dragon spacecraft became the first commercial spacecraft to deliver cargo to and from the International Space Station. In 2020, SpaceX became the first commercial company to bring astronauts to the International Space Station.

SpaceX's design and manufacturing headquarters is in Hawthorne, California. Here, the majority of the launch vehicles and spacecraft are designed and manufactured. The company also has a 4,000 acre rocket testing facility in McGregor, Texas, where SpaceX tests its engines, vehicle structures, and systems and validates every engine for flight and thruster control. The facility is outfitted with sixteen specialized test stands.

The company has launched vehicles from Cape Canaveral Space Force Station in Florida, the Vandenberg Air Force Base on the California Coast, and the Kennedy Space Center in Florida. The company is also constructing a commercial launch site at Starbase in Texas, designed for orbital missions and where Starship vehicles are built and tested.

SpaceX's first vehicle was the Falcon 1 rocket, a two-stage liquid-fueled craft designed to send small satellites into orbit. The Falcon 1 was less expensive to build and operate than launch vehicles developed by competitors, including publicly owned and government-funded companies such as Lockheed Martin and Boeing. Part of the rocket’s cost-effectiveness was made possible by the SpaceX-developed Merlin engine, a cheaper alternative to those used by other companies. SpaceX also focused on making these rockets and launch vehicles reusable, rather than being single use as most launch vehicles and rockets have been.

Falcon 1 rocket launched from the Kwajalein Atoll in September 2008.

In March 2006, SpaceX made its first Falcon 1 launch. The launch was successful until a fuel leak and a fire ended the launch prematurely. However, the company, through its demonstrated capabilities and less expensive rockets, earned millions of dollars in launching orders, many from the US government. In August of that year, SpaceX was a winner of a NASA competition for funds to build and demonstrate spacecraft that could potentially service the ISS after NASA decommissioned the space shuttle. Following this, there were Falcon 1 launch that failed to attain Earth orbit in March 2007 and August 2008. In September 2008, SpaceX successfully launched the Falcon 1 rocket into Earth orbit and became the first privately owned company to send a liquid-fueled rocket into orbit. Three months later, it won a NASA contract for servicing the ISS worth more than $1 billion.

Merlin 1C Vacuum rocket engine.

The Merlin is a family of rocket engines developed by SpaceX. The engines use RP-1 and liquid oxygen as propellants in a gas-generator power cycle. Originally designed for sea recovery and reuse, the Merlin family of engines have been used on the Falcon family of launch vehicles, including the Falcon 1, Falcon 9, and Falcon Heavy. The Merlin uses a pintle type injector, similar to those used in the Apollo Lunar Module landing engine, with propellants fed by a single-shaft, dual-impeller turbopump, which provides high-pressure fluid for the hydraulic actuators. The engine recycles the fluid into a low-pressure inlet and, in doing so, eliminates the need for a separate hydraulic drive system and removes the possibility of failures through loss of hydraulic fuel. SpaceX has developed multiple revisions of the Merlin rocket engine, including the Merlin 1A, 1B, 1C, the Merlin Vacuum (1C), the Merlin 1D, and the Merlin 1D Vacuum.

The Merlin rocket engine contains a triple-redundant design in its system, which incorporates three computers in each processing unit that check on each other for a fault-tolerant design. The turbopump used in the Merlin rocket engine can spin at 36,000 revolutions per minute and is capable of delivering 10,000 horsepower.

As of August 2011, SpaceX produced Merlin engines at a rate of 8 per month. In September 2013, SpaceX increased the size of the manufacturing space and configured it to produce at a rate of 40 rocket cores per year and utilize 400 engines annually. In October 2014, SpaceX announced the 100th Merlin 1D engine had been manufactured, and the manufacturing capabilities had been increased to 4 rocket engines produced per week. The production of Merlin engines was increased in order to keep up with larger launch vehicles.

As of 2021, SpaceX launched 111 Falcon 9 and Falcon Heavy rocket missions, with all but one Falcon 9 flight having nine Merlin engines and each Falcon Heavy having twenty-eight engines, adding up to 1,163 Merlin engine flights since the development and consistent launch of the Falcon 9—more than any other large US rocket engine and with a 99.7 percent launch success record.

In 2010, SpaceX first launched its Falcon 9, a bigger version of the Falcon 1 and named for its use of nine engines. The Falcon 9 was designed to have a first stage that could be reused. And in 2015, the capability was proven, with a Falcon 9 first stage that returned to Earth near its launch site. In 2017, a rocket stage previously returned to Earth was reused in a launch. As of 2021, the Falcon 9 had successfully landed eighty-two times and had reflown sixty-four rockets. The launch vehicle is intended for transport of people and payloads into orbit and beyond. The reusability of the rocket allows the most expensive components to be reflown, which makes space flight less expensive.

Falcon 9 launch.

The Falcon 9 rocket is capable of carrying a 22,800 kg payload to low-Earth orbit, a 8,300 kg payload to geostationary transfer orbit, and a possible 4,020 kg payload to Mars. The launch vehicles incorporate the nine Merlin engines, which throttle near the end of the first stage to limit the launch vehicle acceleration as the rocket's mass decreases with fuel being burned, and to ensure the launch vehicle could reorient prior to reentry and decelerate for landing. To land the Falcon 9, the rocket deploys four landing legs made of carbon fiber with an aluminum honeycomb.

Falcon 9 rocket with a fairing payload carrying Starlink satellites.

The second stage of the rocket is a single Merlin Vacuum Engine, which delivers the payload of the Falcon 9 rocket to the desired orbit. The second stage engine is capable of restarting multiple times to achieve the desired orbit. First and second stages of the Falcon 9 are connected by an interstage, which houses the pneumatic pushers that allow the first and second stage to separate during flight. Depending on the Falcon 9's launch priorities, the rocket can be equipped with a fairing payload, which is used for launching satellites and is manufactured of composite materials. The fairing cover has been recovered for future missions. And for crewed missions, the Falcon 9 can carry the Dragon module, which is capable of carrying up to seven people or cargo in a pressurized section that can accommodate secondary payloads and can be used to connect to the ISS.

In 2011, SpaceX broke ground on a launch site for the Falcon Heavy, a launch vehicle designed to break the $1,000-per-pound-to-orbit cost barrier and could be used to transport astronauts into deep space. The Falcon Heavy rocket had its first test flight in 2018. Two of the three first stages landed successfully; the third hit the water near the drone ship. That Falcon Heavy's payload was a Tesla Roadster, with a mannequin in a space suit buckled into the driver’s seat. The Falcon Heavy is similar to the Falcon 1 and Falcon 9, except it has been outfitted with twenty-nine Raptor rocket engines, rather than the Merlin engines. The configuration is expected to have thirty-three engines.

The Falcon Heavy rocket with two boosters.

The Falcon Heavy has also been composed of nine Falcon 9 nine-engine cores, composed of twenty-seven Merlin engines, with more than 5 million pounds of thrust at liftoff. The rocket has the ability to lift 64 metric tons to a low-Earth orbit. Otherwise, the rocket is capable of carrying a 26,700 kg payload to geosynchronous transfer orbit, and a 16,800 kg payload to Mars. The Falcon Heavy is made of three cores in the first stage, with the boosters connected to the main rocket at the nosecone, the interstage, and on the octaweb. After liftoff, the center core engines are throttled down for the boosters to separate before the center engine throttles back to full thrust. For the interstage, second stage, and payload design, the Falcon Heavy draws on the same components of the Falcon 9 rocket.

As well, the Falcon Heavy is expected to take flight with the company's Booster 4, a super heavy rocket booster. This is a massive, single-core rocket that is 70 meters tall, has a diameter of 9 meters, and has thrust capabilities around double that of the Saturn V rocket.

The sea-level variant of the Raptor engine on left, and the vacuum variant on the right.

The Raptor engine was initially unveiled in 2017 under the name "BFR" and was developed to power a Mars-bound rocket. The rocket is powered by liquid oxygen and methane, with the fuel intended to enable astronauts to fly to Mars and refuel using resources from the planet. The engines were developed with the Starship prototype, which has reached a height of 33,000 feet in test flights. The engine has a sea-level variant, which is used by the Super Heavy Booster to get a payload into orbit, and a vacuum variant optimized for space.

The Raptor engine uses a full-flow staged combustion engine—only the third engine in history to employ this technique. This is different from the Merlin's open cycle system. The previous two attempts at a full-flow stage engine were in the 1960s in the former Soviet Union and in the United States in the early 2000s. Neither engine made it beyond testing.

Raptor engine during test burn.

A full-flow stage combustion engine refers to how the pump spins a turbine to drive an engine. In a normal open cycle engine, this process expends some of the propellant to start the process. In the Raptor, every drop of the propellant is made available to create an efficient rocket engine. This is done through the engine burning the fuel at high enough pressure to steer the fire from preburner back into the combustion chamber. This is not only more efficient than the Merlin engine but also capable of creating greater thrust than the Merlin. The Raptor engine operates at three times greater pressure than the Merlin engine, around 300 bars in the main chamber of the engine, which has required the development of a new metal alloy. As well, as the Raptor engine burns methane rather than kerosene, which is a lower cost and higher performing fuel. A higher performing fuel allows for the size reduction of the Raptor engine compared to the Merlin.

The Dragon Capsule was developed by SpaceX for carrying astronauts and cargo and is capable of docking with the ISS in order to transfer astronauts and supply the ISS with cargo.In December 2010, the company became the first commercial company to release a spacecraft into orbit and return it to Earth. The Dragon capsule again made history on May 25, 2012, when it became the first commercial spacecraft to dock with the ISS, to which it successfully delivered cargo. The Dragon capsule is also considered to be possible for use for space tourism flights by NASA and for a concept proposed by SpaceX called DragonLab, which would turn the dragon spacecraft into a free-flying laboratory carrying experiments for missions ranging from one week to two years in duration.

The Dragon Capsule approaching the ISS.

In 2021, the Dragon capsule was used to bring time-sensitive science experiments back to Earth from the ISS. Experiments include Cardinal Heart, which studies how changes in gravity affect cardiovascular cells and tissues; Space Organogenesis, a study by the Japan Aerospace Exploration Agency to demonstrate the growth of 3D organ buds from human stem cells in order to analyze changes in gene expression; the Bacterial Adhesion and Corrosion experiment, which identifies bacterial genes during biofilm growth to examine whether the biofilms can corrode stainless steel and to evaluate the effectiveness of silver-based disinfectant; Fiber Optic Production, which includes the return of experimental optical fibers created in microgravity using zirconium, barium, lanthanum, sodium, and aluminum; and Rodent Research-23, which involves the return of live mice in a study of the function of arteries, veins, and lymphatic structures in the eye and changes in the retina before and after spaceflight.

The Dragon Spacecraft is comprised of two portions—the unpressurized section and the pressurized section. The unpressurized section, also known as the trunk, has a volume of 37 m³ and works to support the spacecraft during ascent and while on station. The trunk has solar panels on one side for power generation and remains attached to the pressurized section until shortly before reentry. The pressurized section, or the capsule, has a volume of 9.3 m³ and allows for the transport of people and environmentally sensitive cargo. The capsule is equipped with Draco thrusters for maneuvering.

Draco thruster engines firing to separate the Dragon spacecraft from the Falcon 9 second stage.

The Draco is a thruster equipped on the Dragon spacecraft for orientation during the mission, including apogee and perigee maneuvers, orbit adjustment, and attitude control. The thruster is capable of generating 90 pounds of force in the vacuum of space, and the Dragon spacecraft is equipped with sixteen Draco thrusters. The Draco thrusters are hypergolic liquid rocket engines that use monomethyl hydrazine as a fuel and nitrogen tetroxide as an oxidizer, which have a long on-orbit lifetime and provide the Dragon spacecraft the capability of remaining berthed at the ISS for a year or more and enable it to serve as an emergency lifeboat if needed. The Draco thrusters are a part of the reaction control system, or RCS.

The SuperDraco Thruster.

Part of the Draco family of thrusters, the SuperDraco engine is intended to offer fault-tolerant propulsion for the Dragon's launch escape system. There are eight SuperDraco engines arrayed around the Dragon spacecraft, and in the event of an emergency, the SuperDraco engines can power the Dragon a half mile away from the launch vehicle in less than eight seconds. This larger version of the Draco engine delivers 100 times the thrust of the smaller engine. On top of being a redundant system and a critical resource in the case of an aborted flight, the SuperDraco provides thrust for landing the Dragon during nominal launches. The SuperDraco uses the same hypergolic propellants as the Draco. An individual SuperDraco thruster is capable of producing 16,400 pounds of thrust. The total power of the eight-thruster system, which is clustered in four pairs, is 122,600 pounds. The thrusters have a 20 cm exit nozzle and an exhaust velocity of 2,300 meters per second. This allows for the Dragon spacecraft to accelerate from zero to one hundred miles per hour in 1.2 seconds.

The Starship, a spacecraft designed to provide fast transportation between cities on Earth and for the colonization of moon and Mars, is a larger scale spacecraft intended to replace other space vehicles. SpaceX plans to use the Starship for a flight around the moon carrying Japanese businessman Maezawa Yusaku and several artists in 2023 and to launch settlers to Mars in the mid-2020s.

Starship at the SpaceX test center.

The Starship prototype completed its fifth high-altitude flight test from Starbase in Texas on May 5, 2021. The ship is powered by three Raptor engines, each of which shut down in sequence prior to the vehicle reaching apogee. After reaching the desired altitude, the shuttle was able to descend under active aerodynamic control and by independent movement of two forward and two aft flaps. These flaps were controlled by the onboard flight computer for control of Starship's attitude during flight and the Starship proved capable of precise landing.

The Starship payload fairing is 9 meters in diameter and 18 meters high, with a resulting payload volume of 1,100 m³, which can be configured for both crew and cargo. The use cases proposed for the Starship include satellite delivery, which is proposed to be done at a lower cost per launch than SpaceX's own Falcon vehicles. This can include new satellite deployment due the to Starship's large fairing. Another proposed use for the Starship is for travel to Mars and the moon.

Image of the Super Heavy booster rocket.

The Starship is propelled by the Super Heavy first stage or booster rocket. The Super Heavy uses sub-cooled liquid methane and liquid oxygen propellants in its Raptor engines, with a gross liftoff mass of over 3 million kg. The booster also uses six legs to land on its return to Earth.

Illustration of a proposed SpaceX lander for NASA's Artemis program.

In April 2021, SpaceX was announced as a partner for NASA and NASA's mission to return to the moon and explore the moon as part of NASA's Artemis program. As per the partnership, SpaceX is given a firm-fixed, milestone-based contract with a total award value of $2.89 billion. This is to continue development of a commercial human lander to bring American astronauts to the lunar surface. SpaceX is expected to work closely with NASA in the initial phases of the lander design to ensure it meets NASA's performance requirements and standards. The initial expectation is the resulting lander will use SpaceX's Raptor engines and the Starship architecture, if not a similar architecture. This is to provide a fully reusable launch and landing system. Project Artemis, and by extension the contract with SpaceX, is considered an important step for NASA in its long-term plan for deep space exploration.

SpaceX has a stated goal of reaching Mars using the Starship flight program. This is in part because the atmosphere on Mars is expected to be capable of being manipulated to warm the planet up and be used for agriculture through compression of the atmosphere. The mission is expected to take six months to reach Mars. And part of the capability of reaching Mars and being able to return is the Raptor engine's fuel source, which is expected to be capable of being produced on Mars. The Starship platform is also developed with the capability for refilling on orbit, which would allow for the transport of the ship to Mars.