It will also be the first time in history a privately-built spacecraft will dock with the International Space Station.
NASA and SpaceX are now aiming for a March debut of the first capsule from a private company created to fly astronauts to the International Space Station.
Then will come huge milestones - crewed test flights to the ISS. If all goes well on the upcoming uncrewed missions, test pilots could launch in the Crew Dragon as soon as July and the Starliner in August.
According to NASA, United Launch Alliance is finalizing processing for the Atlas V rocket that will provide the thrust for the Starliner launch from Cape Canaveral Air Force Station's launch complex 41.
Boeing's first uncrewed test flight of its CST-100 Starliner vehicle, previously scheduled for March, is now expected no earlier than April.
After the Crew Dragon completes its first test flight, SpaceX aims to have the capsule's first manned mission take place in July, which is a bit later than planned. NASA astronauts Michael Fincke and Nicole Aunapu Mann, as well as Boeing astronaut Christopher Ferguson will participate in the second flight.More news: Your Spotify account may be terminated if you try to block ads
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"We are excited about seeing the hardware we have followed through development, integration, and ground testing move into flight".
These adjustments allow for completion of necessary hardware testing, data verification, remaining NASA and provider reviews, as well as training of flight controllers and mission managers.
The Crew Dragon will blast off towards the ISS for two weeks in a bid to prove its reliability and safety in carrying astronauts into space.
It would be the first launch of US astronauts into orbit, from USA soil, since NASA's shuttle program ended in 2011. "NASA has been working together with SpaceX and Boeing to make sure we are ready to conduct these test flights and get ready to learn critical information that will further help us to fly our crews safely".
SpaceX also completed a pad abort test in 2015.
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Astronauts haven't been launched from the U.S. since the shuttering of NASA's longstanding shuttle program in 2011.