SpaceX Dragon spacecraft
On 16 September 2014 NASA selected SpaceXís Falcon 9 launch vehicle and Dragon spacecraft to fly American astronauts to the International Space Station under the Commercial Crew Program. Under the $2.6 billion contract, SpaceX will launch the Crew Dragon spacecraft atop the Falcon 9 launch vehicle from Kennedy Space Center in Cape Canaveral, Florida. As a modern, 21st century manned spacecraft, Crew Dragon will be capable of carrying up to seven crewmembers, landing propulsively almost anywhere on Earth, and refueling and flying again for rapid reusability. Dragon was designed from the beginning to carry humans, and the upgraded human-rated vehicle will be one of the safest, most reliable spacecraft ever flown. The vehicle holds seats for 7 passengers, and includes an Environmental Control and Life Support System (ECLSS) that provides a comfortable environment for crewmembers.
Crew Dragonís powerful launch escape system, the first of its kind, will provide escape capability from the time the crew enters the vehicle all the way to orbit. Should an emergency occur during launch, eight SuperDraco engines built into the side walls of the Dragon spacecraft will produce up to 120,000 pounds of axial thrust to carry astronauts to safety.
Dragon is a free-flying spacecraft designed to deliver both cargo and people to orbiting destinations. Dragon made history in 2012 when it became the first commercial spacecraft in history to deliver cargo to the International Space Station and safely return cargo to Earth, a feat previously achieved only by governments. It is the only spacecraft currently flying that is capable of returning significant amounts of cargo to Earth. Currently Dragon carries cargo to space, but it was designed from the beginning to carry humans. Under an agreement with NASA, SpaceX is now developing the refinements that will enable Dragon to fly crew.
The pressurized section of the spacecraft, also referred to as the capsule, is designed to carry both cargo and humans into space. Towards the base of the capsule but outside the pressurized structure are the Draco thrusters, Dragon's guidance navigation and control (GNC) bay and Dragonís advanced heat shield.
Dragonís trunk supports the spacecraft during ascent to space, carries unpressurized cargo and houses Dragonís solar arrays. The trunk and solar arrays remain attached to Dragon until shortly before reentry to Earthís atmosphere, when they are jettisoned.
he Dragon spacecraft has three configurations to meet a variety of needs: cargo, crew and DragonLab. To ensure a rapid transition from cargo to crew capability, the cargo and crew configurations of Dragon are almost identical. This commonality simplifies the human rating process, allowing systems critical to crew and space station safety to be fully tested on unmanned cargo flights. With DragonLab, essentially the same spacecraft can be used as a platform for in-space technology demonstrations and experiments.
Dragon is the first commercial spacecraft to deliver cargo to the International Space Station and currently the only cargo spacecraft flying capable of returning significant amounts of cargo to Earth. Dragon accommodates pressurized cargo in the capsule as well as unpressurized cargo in its trunk. The racks are a honeycomb carbon-aluminum construction designed for efficient packing in a zero-gravity environment. They accommodate a variety of standard-size NASA cargo bags as well as freezers for carrying materials such as biological samples.
Boeing and SpaceX each faced significant safety and technical challenges with parachutes, propulsion, and launch abort systems that need to be resolved prior to receiving NASA authorization to transport crew to the ISS. The complexity of these issues has already caused at least a 2-year delay in both contractorsí development, testing, and qualification schedules and may further delay certification of the launch vehicles by an additional year. Consequently, given the amount, magnitude, and unknown nature of the technical challenges remaining with each contractorís certification activities, CCP will continue to be challenged to establish realistic launch dates. Furthermore, final vehicle certification for both contractors will likely be delayed at least until summer 2020 based on the number of ISS and CCP certification requirements that remain to be verified and validated.
SpaceX chose a design that uses four parachutes. Originally, when first designing the Dragon 2 capsule, SpaceX had intended to use its propulsion systems for landing, with parachutes considered a backup system. As a result, the parachutes were developed using more lightweight and less robust materials. Given the effort required to qualify the propulsion system for safe operation, SpaceX decided to rely fully on its parachutes for landing, a system that would later require design modifications.
In August 2018, SpaceX experienced failures on two main parachute canopies during the return of its Dragon capsule from a cargo resupply mission to the ISS. This resulted in additional work to improve load balancing on the planned crewed parachute system. However, the parachute design for SpaceX cargo missions uses three instead of four parachutes and receives more turbulence from the cargo capsule compared to a crew capsule and therefore they are not suitable for direct comparison to one another. In April 2019, SpaceX experienced an anomaly during an air drop test intended to demonstrate that the Dragon 2 capsule could safely land with three instead of four parachutes. During the test, the three parachutes failed, resulting in the loss of the test sled.
In April 2019, SpaceXís Dragon 2 exploded during a static fire test of its launch abort system. The spacecraft was the same uncrewed vehicle that flew to and returned safely from the ISS in March 2019. An anomaly occurred during the test just before ignition of the SuperDraco thrusters, resulting in the destruction of the spacecraft. In July 2019, SpaceXís preliminary report traced the anomaly to components in the propulsion system that ignited due to fluid trapped in the lines during pressurization of the system, causing the explosion.
A SpaceX test of parachute systems for its new Crew Dragon manned capsule ended in failure 24 March 2020, with a helicopter dropping the test article from an unknown height. During a planned parachute drop test, the test article suspended underneath the helicopter became unstable. Out of an abundance of caution and to keep the helicopter crew safe, the pilot pulled the emergency release. As the helicopter was not yet at target conditions, the test article was not armed, the parachute system did not initiate the parachute deployment sequence. The company said it did not consider the mishap a failure of the parachute system itself.
NASAís SpaceX Demo-2 flight test will send two astronauts to the International Space Station as part of the agencyís Commercial Crew Program. This mission will be the return of human spaceflight launch capabilities to the United States and the first launch of American astronauts aboard an American rocket and spacecraft since the final space shuttle mission on July 8, 2011. SpaceXís Falcon 9 rocket will launch Crew Dragon, with NASA astronauts Bob Behnken and Doug Hurley aboard the spacecraft, from Launch Complex 39A at NASAís Kennedy Space Center in Florida. NASA and SpaceX were currently targeting no earlier than mid-to-late May 2020 for launch.
At 3:22 pm US Eastern Time on 30 May 2020, a SpaceX Falcon 9 rocket lifted off from Florida, bearing a spaceship called Crew Dragon with two men inside - NASA astronauts Bob Behnken and Doug Hurley. It was the first time that US astronauts were sent into space from US soil after a nine-year gap.