On Thursday, NASA revealed the profiles of the four astronauts who were picked to fly its first commercial space flights. The crew of veteran astronauts will be flying the capsules built by SpaceX and Boeing to the International Space Station (ISS) beginning 2017, according to CBS News.

Robert Behnken, Eric Boe, Doug Hurley and Sunita "Suni" Williams will begin their training for the Dragon crew capsule and the CST-100.

Behnken is an Air Force colonel who was with the Endeavour missions in 2008 and 2010 as a specialist. Boe is also an Air Force colonel who was with Endeavour in 2008 as its pilot and the final Discovery spaceflight in 2011. Hurley is a Marine colonel who was part of the Endeavour crew in 2009 as its pilot and the Atlantis' final mission in 2011. Williams, a Navy captain, was in space missions between 2006-2007 and 2012. She is the record holder for a cumulative spacewalk time by a female astronaut (50 hours and 40 minutes), according to NBC News.

"These distinguished, veteran astronauts are blazing a new trail, a trail that will one day land them in the history books and Americans on the surface of Mars," NASA Administrator, Charles Bolden said in a statement.

"It's really been the dream of all of us to participate in the test of a new vehicle, and a vehicle like a spacecraft is probably the gem, if you will, of a career," Behnken said during a press conference.

"To be part of a new test program ... is extremely exciting. The challenge from a test pilot perspective is great, and I'm just looking forward to (getting) from today all the way up to the space station," Hurley said.

Last year, NASA awarded SpaceX and Boeing the contract for the commercial space flights. With $2.6 billion, SpaceX was tasked to build the Dragon cargo spacecraft, while Boeing had $4.2 billion to build the CST-100.

"For the crewed test flights, two NASA astronauts will fly on the SpaceX Crew Dragon, and one NASA and one Boeing astronaut will fly on the Boeing CST-100. The companies each proposed the composition based on their unique approaches to meet NASA's requirements. NASA requires the flight test program include a crewed flight to the International Space Station. This minimally crewed flight must include a NASA crew, dock with the International Space Station, remain docked for a sufficient duration to check out space station interfaces, then return to a supported landing site," NASA said, according to NBC News.

For more coverage on SpaceX and Boeing missions, check out the related links below.