Boeing [BA] and Space Exploration Technologies Corp. (SpaceX) on Tuesday won a pair of contracts from NASA totaling $6.8 billion for Commercial Crew (CCP), the civil space agency’s highly-anticipated effort to taxi astronauts to and from the International Space Station (ISS) by 2017.

Boeing was awarded $4.2 billion and SpaceX $2.6 billion, a NASA official said Tuesday during a briefing. Sierra Nevada Corp. (SNC) and Jeff Bezos-backed Blue Origin lost out on Commercial Crew, which is provide an alternative to relying on Russia for traveling back and forth to ISS. SNC had proposed its Dream Chaser space vehicle that looked like the Space Shuttle. Blue Origin offered its biconic-shaped “Space Vehicle,” according to a 2012 statement.

Photo: NASA.
Photo: NASA.

Astronauts will fly on Boeing’s CST-100 and SpaceX’s Dragon Verson 2 space capsule, NASA said on Twitter. NASA’s contracts include at least one crewed flight test per company to verify the integrated rocket and spacecraft system can launch, maneuver in orbit and dock to ISS.

Once the test program has been successfully completed and the systems achieve NASA certification, the contractors also complete at least two, and as many as six, crewed missions to ISS. Boeing and SpaceX will be paid based on performance of milestones, a NASA official said during an announcement Tuesday.

SNC spokeswoman Michelle Erlach said Tuesday in a statement the company plans to have a debrief session with NASA soon. When debriefing concludes, Erlach said, SNC will elaborate further on its future options regarding the contract decision and the Dream Chaser program.

Blue Origin declined to comment Tuesday. SpaceX did not respond to a request for comment by press time.

Boeing said it will build three CST-100s at its Kennedy Space Center, Fla., facility. The spacecraft will undergo a pad abort test in 2016 and an uncrewed flight in early 2017, leading up to the first crewed flight to ISS in mid-2017, according to a statement. Boeing said it was the only Commercial Crew competitor to pass a critical design review (CDR) as well as complete all CCP milestones on time and budget.