Dragon V2

Dragon 2 is a class of partially reusable spacecraft developed, manufactured, and operated by the American space company SpaceX for flights to the International Space Station (ISS) and private spaceflight missions. The spacecraft, which consists of a reusable space capsule and an expendable trunk module, has two variants: the 4-person Crew Dragon and Cargo Dragon, a replacement for the Dragon 1 cargo capsule. The spacecraft launches atop a Falcon 9 Block 5 rocket, and the capsule returns to Earth through splashdown.

Crew Dragon's primary role is to transport crews to and from the ISS under NASA's Commercial Crew Program, a task handled by the Space Shuttle until it was retired in 2011. It will be joined by Boeing's Starliner in this role when NASA certifies it. Crew Dragon is also used for commercial flights to ISS and other destinations and is expected to be used to transport people to and from Axiom Space's planned space station.

Cargo Dragon brings cargo to the ISS under a Commercial Resupply Services-2 contract with NASA, a duty it shares with Northrop Grumman's Cygnus spacecraft. As of January 2025, it is the only reusable orbital cargo spacecraft in operation, though it may eventually be joined by the under-development Sierra Space Dream Chaser spaceplane.

Development and variants

There are two variants of Dragon 2: Crew Dragon and Cargo Dragon.Audit of Commercial Resupply Services to the International Space Station
NASA 26 April 2018 Report No. IG-18-016 Quote: "For SpaceX, certification of the company's unproven cargo version of its Dragon 2 spacecraft for CRS-2 missions carries risk while the company works to resolve ongoing concerns related to software traceability and systems engineering processes" Crew Dragon was initially called "DragonRider" and it was intended from the beginning to support a crew of seven or a combination of crew and cargo. Earlier spacecraft had a berthing port and were berthed to ISS by ISS personnel. Dragon 2 instead has an IDSS-compatible docking port to dock to the International Docking Adapter ports on ISS. It is able to perform fully autonomous rendezvous and docking with manual override ability. For typical missions, Crew Dragon remains docked to the ISS for a nominal period of 180 days, but is designed to remain on the station for up to 210 days, matching the Russian Soyuz spacecraft. "Spaceship teams seek more funding"
MSNBC 10 December 2010 Retrieved 14 December 2010

Crew Dragon

Crew Dragon is capable of autonomous operation. SpaceX and NASA state that it is capable of carrying seven astronauts, but in normal operations, it carries two to four crew members, and , has never carried more than four.

Crew Dragon includes an integrated pusher launch escape system whose eight SuperDraco engines can separate the capsule away from the launch vehicle in an emergency. SpaceX originally intended to use the SuperDraco engines to land Crew Dragon on land; parachutes and an ocean splashdown were envisioned for use only in the case of an aborted launch. Precision water landing under parachutes was proposed to NASA as "the baseline return and recovery approach for the first few flights" of Crew Dragon. However, propulsive landing was later cancelled, leaving ocean splashdown under parachutes as the only option.

In 2012, SpaceX was in talks with Orbital Outfitters about developing space suits to wear during launch and re-entry. Each crew member wears a custom-fitted space suit that provides cooling inside the Dragon (IVA type suit) but can also protect its wearer in a rapid cabin depressurization. For the Demo-1 mission, a test dummy was fitted with the spacesuit and sensors. The spacesuit is made from Nomex, a fire-retardant fabric similar to Kevlar.

The spacecraft's design was unveiled on 29 May 2014, during a press event at SpaceX headquarters in Hawthorne, California. In October 2014, NASA selected the Dragon spacecraft as one of the candidates to fly American astronauts to the International Space Station, under the Commercial Crew Program. In March 2022, SpaceX President Gwynne Shotwell told Reuters that "We are finishing our final (capsule), but we still are manufacturing components, because we'll be refurbishing". SpaceX later decided to build a fifth Crew Dragon capsule, to be available by 2024. SpaceX also manufactures a new expendable trunk for each flight.

SpaceX's Commercial Crew Transportation Capabilities (CCtCap) contract values each seat on a Crew Dragon flight to be around US$88 million, while the face value of each seat has been estimated by NASA's Office of Inspector General (OIG) to be around US$55 million. This contrasts with the 2014 Soyuz launch price of US$76 million per seat for NASA astronauts.

Cargo Dragon

Dragon 2 was intended from the earliest design concept to carry crew, or with fewer seats, both crew and cargo.

The cargo version, dubbed Cargo Dragon, became a reality after 2014, when NASA sought bids on a second round of multi-year contracts to bring cargo to the ISS in 2020 through 2024. In January 2016, SpaceX won contracts for six of these flights, dubbed CRS-2. , Cargo Dragon has completed nine missions to and from the ISS with six more planned.

Cargo Dragons lack several features of the crewed variant, including seats, cockpit controls, astronaut life support systems, and SuperDraco abort engines. Cargo Dragon improves on many aspects of the original Dragon design, including the recovery and refurbishment process.

Since 2021, Cargo Dragon has been able to provide power to some payloads, saving space in the ISS and eliminating the time needed to move the payloads and set them up inside. This feature, announced on 29 August 2021 during the CRS-23 launch, is called Extend-the-Lab. "For CRS-23 there are 3 Extend-the-Lab payloads launching with the mission, and once docked, a 4th which is currently already on the space station will be added to Dragon". For the first time, Dragon performed test reboost of the ISS via its aft-facing Draco thrusters on 8 November 2024 at 17:50 UTC.

The US Deorbit Vehicle is a planned Cargo Dragon variant that will be used to deorbit the ISS and direct any remnants into the " spacecraft cemetery", a remote area of the southern Pacific Ocean. The vehicle will attach to the ISS using one of the Cargo Dragon vehicles, which will be paired with a longer trunk module equipped with 46 Draco thrusters (instead of the normal 16) and will carry of propellant, nearly six times the normal load. NASA plans to launch the deorbit vehicle in 2030 where it will remain attached, dormant, for about a year as the station's orbit naturally decays to . The spacecraft is to then conduct one or more orientation burns to lower the perigee to , followed by a final deorbiting burn. In June 2024, NASA awarded a contract worth up to $843 million to SpaceX to build the deorbit vehicle as it works to secure funding.

Design

SpaceX, which aims to dramatically lower space transportation costs, designed Dragon 2 to be reused, not discarded as is typical of spacecraft. It is composed of a reusable capsule and a disposable trunk.

SpaceX and NASA initially certified the capsule to be used for five missions. , they are working to certify it for up to fifteen missions.

To maximize cost-effectiveness, SpaceX incorporated several innovative design choices. The Crew Dragon employs eight side-mounted SuperDraco engines for its emergency escape system, eliminating the need for a traditional, disposable escape tower. Furthermore, instead of housing the critical and expensive life support, thruster, and propellant storage systems in a disposable service module, Dragon 2 integrates them within the capsule for reuse.

The trunk serves as an adapter between the capsule and the Falcon 9 rocket's second stage and also includes solar panels, a heat-dissipation radiator, and fins to provide aerodynamic stability during emergency aborts. Dragon 2 integrates solar arrays directly into the trunk's structure, replacing the deployable panels of its predecessor, Dragon 1. The trunk can also accommodate unpressurized cargo, such as the Roll Out Solar Array transported to the ISS. The trunk is connected to the capsule using a fitting known as "the claw."

The typical Crew Dragon mission includes four astronauts: a commander who leads the mission and has primary responsibility for operating the spacecraft, a pilot who serves as backup for both command and operations and two mission specialists who may have specific duties assigned depending on the mission. However, the Crew Dragon can fly missions with just two astronauts as needed, and in an emergency, up to seven astronauts could return to Earth from the ISS on Dragon.

On the ground, crews enter the capsule through a side hatch.

On the Crew Dragon, above the two center seats (occupied by the commander and pilot), there is a three-screen control panel. Below the seats is the cargo pallet, where around of items can be stowed. The capsule’s ceiling includes a small space toilet (with privacy curtain), and an International Docking System Standard (IDSS) port. For private spaceflight missions not requiring ISS docking, the IDSS port can be replaced with a domed plexiglass window offering panoramic views, similar to the ISS Cupola. Additionally, SpaceX has developed a "Skywalker" hatch for missions involving extravehicular activities.

The Cargo Dragon is also loaded from the side hatch and has an IDSS port on the ceiling. However, it lacks the control panels, windows, and seats of the Crew Dragon.

The spacecraft can be operated in full vacuum, and "the crew will wear SpaceX-designed space suits to protect them from a rapid cabin depressurization emergency event". The spacecraft has also been designed to be able to land safely with a leak "of up to an equivalent orifice of in diameter".

The spacecraft's nose cone protects the docking port and four forward-facing thrusters during ascent and reentry. This component pivots open for in-space operations. Dragon 2's propellant and helium pressurant for emergency abort and orbital maneuvers are stored in composite-carbon-overwrap titanium spherical tanks at the capsule's base in an area known as the service section.

For launch aborts, the capsule relies on eight SuperDraco engines arranged in four redundant pairs. Each engine generates of thrust. Sixteen smaller Draco thrusters placed around the spacecraft control its attitude and perform orbital maneuvers.

When the capsule returns to Earth, a PICA-3 heat shield safeguards the capsule during reentry. Dragon 2 uses a total of six parachutes (two drogues and four mains) to decelerate after atmospheric entry and before splashdown, compared to the five used by Dragon 1. The additional parachute was required by NASA as a safety measure after a Dragon 1 suffered a parachute malfunction. The company also went through two rounds of parachute development before being certified to fly with crew. In 2024, the use of the SuperDraco thrusters for propulsive landing was enabled again, but only as a back-up for parachute emergencies.

Crewed flights

Crew Dragon is used by both commercial and government customers. Axiom Space launches commercial astronauts to the ISS and intends to eventually launch to their own private space station. NASA flights to the ISS have four astronauts, with the added payload mass and volume used to carry pressurized cargo.

On 16 September 2014, NASA announced that SpaceX and Boeing had been selected to provide crew transportation to the ISS. SpaceX was to receive up to US$2.6 billion under this contract to provide development test flights and up to six operational flights. Dragon was the less expensive proposal, but NASA's William H. Gerstenmaier considered the Boeing Starliner proposal the stronger of the two. However, Crew Dragon's first operational flight, SpaceX Crew-1, was on 16 November 2020 after several test flights, while Starliner suffered multiple problems and delays, with its first operational flight slipping to no earlier than early 2025.

In a departure from the prior NASA practice, where construction contracts with commercial firms led to direct NASA operation of the spacecraft, NASA is purchasing space transport services from SpaceX, including construction, launch, and operation of the Dragon 2.

NASA approved a new propellant loading procedure due to the Falcon 9 rocket's novel use of superchilled propellants. Unlike earlier NASA spacecraft, such as the Saturn V and Space Shuttle—where propellants were fully loaded hours before launch and before astronauts boarded—on the Falcon 9, propellants are loaded just before launch to keep the liquid oxygen near and the kerosene near . Propellant loading begins approximately 40 minutes before liftoff, with the launch escape system active to ensure the crew can be safely pulled away from the rocket in the event of an emergency during fuel loading.

The first uncrewed test mission, Demo-1, launched to the International Space Station (ISS) on 2 March 2019. After schedule slips, the first crewed flight, Demo-2, launched on 30 May 2020.

Testing

SpaceX planned a series of four flight tests for the Crew Dragon: a pad abort test, an uncrewed orbital flight to the ISS, an in-flight abort test, and finally, a crewed flight to the ISS, which was initially planned for July 2019, but after a Dragon capsule explosion, was delayed to May 2020.

Pad abort test

The pad abort test was conducted successfully on 6 May 2015 at SpaceX's leased SLC-40 launch site. Dragon landed safely in the ocean to the east of the launchpad 99 seconds after ignition of the SuperDraco engines. While a flight-like Dragon 2 and trunk were used for the pad abort test, they rested atop a truss structure for the test rather than a full Falcon 9 rocket. A crash test dummy embedded with a suite of sensors was placed inside the test vehicle to record acceleration loads and forces at the crew seat, while the remaining six seats were loaded with weights to simulate full-passenger-load weight. The test objective was to demonstrate sufficient total impulse, thrust and controllability to conduct a safe pad abort. A fuel mixture ratio issue was detected after the flight in one of the eight SuperDraco engines causing it to under perform, but did not materially affect the flight.

On 24 November 2015, SpaceX conducted a test of Dragon 2's hovering abilities at the firm's rocket development facility in McGregor, Texas. In a video, the spacecraft is shown suspended by a hoisting cable and igniting its SuperDraco engines to hover for about 5 seconds, balancing on its 8 engines firing at reduced thrust to compensate exactly for gravity. The test vehicle was the same capsule that performed the pad abort test earlier in 2015; it was nicknamed DragonFly.

Demo-1: orbital flight test

In 2015, NASA named its first Commercial Crew astronaut cadre of four veteran astronauts to work with SpaceX and Boeing – Robert Behnken, Eric Boe, Sunita Williams, and Douglas Hurley. The Demo-1 mission completed the last milestone of the Commercial Crew Development program, paving the way to starting commercial services under an upcoming ISS Crew Transportation Services contract. On 3 August 2018, NASA announced the crew for the DM-2 mission. The crew of two consisted of NASA astronauts Bob Behnken and Doug Hurley. Behnken previously flew as mission specialist on the STS-123 and the STS-130 missions. Hurley previously flew as a pilot on the STS-127 mission and on the final Space Shuttle mission, STS-135.

The first orbital test of Crew Dragon was an uncrewed mission, commonly called "Demo-1" and launched on 2 March 2019. The spacecraft tested the approach and automated docking procedures with the ISS, remained docked until 8 March 2019, then conducted the full re-entry, splashdown and recovery steps to qualify for a crewed mission. Life-support systems were monitored for the entirety the test flight. The same capsule was planned to be re-used in June 2019 for an in-flight abort test before it exploded on 20 April 2019.

Explosion during testing

On 20 April 2019, , the capsule used in the Demo-1 mission, was destroyed in an explosion during static fire testing at the Landing Zone 1 facility. On the day of the explosion, the initial testing of the Crew Dragon's Draco thrusters was successful, with the anomaly occurring during the test of the SuperDraco abort system.

Telemetry, high-speed camera footage, and analysis of recovered debris indicate the problem occurred when a small amount of dinitrogen tetroxide leaked into a helium line used to pressurize the propellant tanks. The leakage apparently occurred during pre-test processing. As a result, the pressurization of the system 100 ms before firing damaged a check valve and resulted in the explosion.

SpaceX modified the Dragon 2 replacing check valves with burst discs, which are designed for single use, and the adding of flaps to each SuperDraco to seal the thrusters prior to splashdown, preventing water intrusion. The SuperDraco engine test was repeated on 13 November 2019 with . The test was successful, showing that the modifications made to the vehicle were successful.

Since the destroyed capsule had been slated for use in the upcoming in-flight abort test, the explosion and investigation delayed that test and the subsequent crewed orbital test.

In-flight abort test

The Crew Dragon in-flight abort test was launched on 19 January 2020 at 15:30 UTC from LC-39A on a suborbital trajectory to conduct a separation and abort scenario in the troposphere at transonic velocities shortly after passing through max Q, where the vehicle experiences maximum aerodynamic pressure. The Dragon 2 used its SuperDraco abort engines to push itself away from the Falcon 9 after an intentional premature engine cutoff, after which the Falcon was destroyed by aerodynamic forces. The Dragon followed its suborbital trajectory to apogee, at which point the spacecraft's trunk was jettisoned. The smaller Draco engines were then used to orient the vehicle for the descent. All major functions were executed, including separation, engine firings, parachute deployment, and landing.

Dragon 2 splashed down at 15:38:54 UTC just off the Florida coast in the Atlantic Ocean. The test objective was to demonstrate the ability to safely move away from the ascending rocket under the most challenging atmospheric conditions of the flight trajectory, imposing the worst structural stress of a real flight on the rocket and spacecraft. The abort test was performed using a Falcon 9 Block 5 rocket with a fully fueled second stage with a mass simulator replacing the Merlin engine.

Earlier, this test had been scheduled before the uncrewed orbital test, however, SpaceX and NASA considered it safer to use a flight representative capsule rather than the test article from the pad abort test.

This test was previously planned to use the capsule C204 from Demo-1, however, C204 was destroyed in an explosion during a static fire testing on 20 April 2019. Capsule C205, originally planned for Demo-2 was used for the In-Flight Abort Test with C206 being planned for use during Demo-2. This was the final flight test of the spacecraft before it began carrying astronauts to the International Space Station under NASA's Commercial Crew Program.

Prior to the flight test, teams completed launch day procedures for the first crewed flight test, from suit-up to launch pad operations. The joint teams conducted full data reviews that needed to be completed prior to NASA astronauts flying on the system during SpaceX's Demo-2 mission.

Demo-2: crewed orbital flight test

On 17 April 2020, NASA Administrator Jim Bridenstine announced the first crewed Crew Dragon Demo-2 to the International Space Station would launch on 27 May 2020. Astronauts Bob Behnken and Doug Hurley crewed the mission, marking the first crewed launch to the International Space Station from U.S. soil since STS-135 in July 2011. The original launch was postponed to 30 May 2020 due to weather conditions at the launch site. The second launch attempt was successful, with capsule C206, later named '' Endeavour'' by the crew, launching on 30 May 2020 19:22 UTC. The capsule successfully docked with the International Space Station on 31 May 2020 at 14:27 UTC. On 2 August 2020, Crew Dragon undocked and splashed-down successfully in the Atlantic Ocean. Launching in the Dragon 2 spacecraft was described by astronaut Bob Behnken as "smooth off the pad" but "we were definitely driving and riding a dragon all the way up ... a little bit less g's [than the Space Shuttle] but more 'alive' is probably the best way I would describe it".

Regarding descent in the spacecraft, Behnken stated, "Once we descended a little bit into the atmosphere, Dragon really came alive. It started to fire thrusters and keep us pointed in the appropriate direction. The atmosphere starts to make noise—you can hear that rumble outside the vehicle. And as the vehicle tries to control, you feel a little bit of that shimmy in your body. ... We could feel those small rolls and pitches and yaws—all those little motions were things we picked up on inside the vehicle. ... All the separation events, from the trunk separation through the parachute firings, were very much like getting hit in the back of the chair with a baseball bat ... pretty light for the trunk separation but with the parachutes it was a pretty significant jolt".

List of vehicles

List of flights

List includes only completed or currently manifested missions. Dates are listed in UTC, and for future events, they are the earliest possible opportunities (also known as dates) and may change.

Crew Dragon flights

Cargo Dragon flights

Timeline

Crew Dragon has flown twelve missions for NASA under its CCDev and CCP programs and, six privately funded crewed missions. Cargo Dragon has flown twelve cargo missions for NASA. For brevity, the Demo-1 mission is not shown.

See also

* Comparison of crewed space vehicles
* Comparison of space station cargo vehicles
* List of crewed spacecraft
* Crew Dragon Launch Abort System
*

Notes

References

External links

Real-time orbital tracking
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uphere.space

Real-time orbital tracking
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isstracker.pl

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SpaceX spacecraft
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