SpaceX's Dragon: First Private Spacecraft to Reach Space Station
The capsule will begin its scheduled three-week-long stay at the orbiting space station. Image released March 3, 2013.
Credit: NASA

The Dragon spacecraft carries cargo to the International Space Station under commercial agreements that NASA has with SpaceX, a private space company founded by entrepreneur Elon Musk. Dragon was the first private spacecraft to berth with the ISS. SpaceX is also developing a crewed version to take astronauts to the space station.

Dragon's first cargo demonstration flight to the station took place in May 2012, and commercial flights began that fall. SpaceX is currently contracted with NASA to do 12 robotic supply flights to the station for a minimum of $1.6 billion.

While SpaceX is busy ferrying cargo to and from the station, the company is also working on a plan to put astronauts on the Dragon spacecraft. In 2014, the company received $2.6 billion from NASA for the latest phase of the Commercial Crew Program, which aims to fly astronauts on American spacecraft. Boeing received $4.2 billion to develop its CST-100 Starliner module.

SpaceX founder Elon Musk has said he named the Dragon spacecraft after the song "Puff, the Magic Dragon," a 1960s tune from folk group Peter, Paul and Mary. Musk chose the name, he said, because critics considered his business plan impossible when he founded SpaceX. In fact, Musk and SpaceX kept Dragon's first 18 months of development secret as the company publicly developed its light Falcon 1 and heavy-lift Falcon 9 rockets.

The news became public in March 2006 after SpaceX and several teammates submitted a proposal for NASA's Commercial Orbital Transportation Services (COTS) demonstration program. NASA accepted the SpaceX proposal in August 2006. SpaceX initially received a contract valued at up to $278 million; later, other milestones were added that boosted the total possible contract value to $396 million.

What SpaceX proposed to do was fly the Dragon spacecraft on three Falcon 9 rocket flights — a rocket that was still under development. At the time, SpaceX planned to fly those flights in the 2008-09 timeframe, but the design, approval and milestone process took years longer than anticipated.

Dragon passed a NASA critical design review in October 2007, marking a key milestone, as this is when the shape of the spacecraft is determined. The next month, SpaceX broke ground for a launch site at Cape Canaveral Air Force Station. This would be the launching pad for Falcon 9 and Dragon, when the time was right.

As Dragon development moved forward, NASA offered more funding in several forms. In April 2008, NASA awarded SpaceX a launch services contract.

Dubbed "indefinite delivery/indefinite quality," the pact allowed for NASA to order anywhere between $20,000 and $1 billion worth of launches from SpaceX through December 2012. "[SpaceX] can compete for NASA missions using the Falcon 1 and Falcon 9 launch vehicles," the firm stated.

Then came a large breakthrough. In December 2008, NASA selected Space X's Falcon 9/Dragon combination for cargo resupply to the International Space Station. The contract was for a minimum of $1.6 billion, with the option to extend services to up to $3.1 billion. Musk stated it was a "tremendous responsibility" for SpaceX, given the approaching retirement of the shuttle program at the time.

The firm placed some communications hardware on the STS-129 shuttle flight in November 2009 to assist with future SpaceX flights to the station. SpaceX launched the Falcon 9 rocket for the first time in June 2010. This flight included a "qualification unit" of the Dragon spacecraft that was primarily supposed to transmit data during its ride into space.

With the test unit successfully flown, SpaceX turned its attention to sending the real thing. The first full-up test of the Dragon spacecraft came on Dec. 8, 2010. The mission was a success. It marked the first time a private unmanned space capsule was recovered safely back on Earth. 

The private Dragon capsule built by SpaceX is seen at the end of the International Space Station's robotic arm during its undocking on Oct. 28, 2012, in this camera view. The Dragon capsule made the first commercial cargo delivery to the space station for NASA.
The private Dragon capsule built by SpaceX is seen at the end of the International Space Station's robotic arm during its undocking on Oct. 28, 2012, in this camera view. The Dragon capsule made the first commercial cargo delivery to the space station for NASA.
Credit: NASA TV

With the world watching, SpaceX prepared to send the first cargo demonstration flight to the station in May 2012. An abort took place after a problem was detected in one of the engines, pushing back the launch a few days. The spacecraft made it into orbit on May 22.

Three days later, Dragon made its final approach to the station. The spacecraft experienced some problems with its laser distance-judging system when the laser got "distracted" and began bouncing signals off the wrong part of the station. SpaceX controllers then narrowed Dragon's view, and the approach proceeded.

Dragon's first official supply run took place in October 2012. While the spacecraft made it into orbit safely, Falcon 9 experienced a problem with one of its rocket engines during flight. SpaceX adjusted the trajectory of the rocket to put Dragon on the right path. Dragon berthed with the station, and then splashed down successfully weeks later in the Pacific Ocean near California.

One Dragon spacecraft was lost en route to the International Space Station in 2015 when the Falcon 9 rocket carrying it failed, causing a catastrophic explosion. Space station flights were delayed by several months while SpaceX addressed the underlying problem. Cargo flights resumed in 2016; a Falcon 9 exploded that year on the launch pad with a commercial payload, once again pushing back flights until 2017.

SpaceX was one of three companies that received commercial resupply contracts from NASA in January 2016. Between SpaceX, Sierra Nevada Corp. and Orbital ATK, the contracts are valued at up to $14 billion. (Who gets how much depends on the exact mix of spacecraft NASA requires for ISS objectives.) NASA also periodically awards more space station cargo missions as required, such as what happened with SpaceX in February 2016. 

One thing that sets Dragon spacecraft apart from other ISS spacecraft is the ability to survive re-entry with delicate cargo on board. NASA commonly uses Dragon spacecraft to send back life sciences experiments (such as experiments requiring that astronauts take samples of urine or blood). The samples are refrigerated in the spacecraft and picked up quickly after splashdown. Dragon can also carry back living creatures, allowing for biological experiments on the ISS.

While Dragon flights make periodic cargo trips to the International Space Station, SpaceX is also working on a human-rated version for NASA's Commercial Crew Program. The company unveiled its design for the crewed spacecraft in 2014 to great fanfare.

The vehicle can hold up to seven astronauts. SpaceX and NASA are hoping this capability will allow International Space Station crews to expand from the current normal level of six people. The first uncrewed test flight is scheduled for November 2018; crewed tests are set for April 2019, NASA has announced.

While the Dragon spacecraft will not be used to get colonists to Mars, Musk has set his sights on launching humans to the Red Planet. Musk has expressed dreams of colonization for many years. In 2016 and 2017, he outlined several plans to establish Martian colonies.

A look inside the SpaceX Dragon capsule and its Falcon 9 rocket.
A look inside the SpaceX Dragon capsule and its Falcon 9 rocket.
Credit: Karl Tate/SPACE.com