Doug Hurley and Bob Behnken are about to become the first astronauts to travel to the International Space Station aboard a craft made by a commercial company instead of a government agency.
Elon Musk's company SpaceX is providing the hardware, and NASA the crew.
The trip, which will be the first to launch NASA astronauts into space from US soil since 2011, was scheduled for Wednesday (local time) but has been postponed until Sunday.
The weather was not clear enough for liftoff, according to CNN.
Here's who they are.
Robert L. Behnken
Behnken, 49, served in the air force and has six spacewalks on his resume. He will be in charge of docking at the International Space Station.
Behnken completed two bachelor's degrees in physics and mechanical engineering in 1988 and 1992 from Washington University before going on to get his master's in mechanical engineering in 1993 at the California Institute of Technology. He then went on to get a Doctorate in Mechanical Engineering from the California Institute of Technology 1997.
After he graduated Behnken joined the Air Force Test Pilot School at Edwards Air Force Base in California, while also serving as a flight test engineer in the Air Force Reserve Officers' Training Corps.
In 2000 he was selected by NASA and, after training, he served as the chief of the space station operations at the Kennedy Space Center. Behnken's first trip to space was in 2008 on the Endeavour to the international space station. He travelled on the Endeavour again in 2010.
Behnken has a six-year-old son and is married to NASA astronaut Megan McArthur.
Douglas G. Hurley
Hurley, 53, served in the US Marines Corps and is in charge of the launch and landing during the trip to the International Space Station.
Hurley completed a bachelor of science degree in civil engineering in 1988 from Tulane University.
Later that same year he became a second lieutenant in the US Marine Corps and completed flight training at the Basic School in Virginia.
In 2000 Hurley joined NASA where, after training, he served as the lead astronaut support personnel for shuttle missions STS-107 and STS-121.
His first trip to space was in 2009 on the Endeavour. He made a second trip in 2011 on the Atlantis.
Hurley is married to fellow NASA astronaut Karen Nyberg and they have one son.
