Boeing's CST-100 and SpaceX's Dragon capsules will be the first new space crafts in a generation to fly astronauts to the International Space Station.
NASA announced Tuesday the companies that will share a $6.8 billion contract to replace the shuttle program.
Boeing gets $4.2 billion. SpaceX will receive $2.6 billion.
Kathy Lueders, manager of NASA's Commercial Crew Program, says each space craft can carry four astronauts.
"This means we can double the amount of scientific research performed on the station today."
The highly anticipated announcement sharpens the future of American space exploration, which had been adrift since the shuttle program ended in 2011.
Since then American astronauts have flown with Russia.
The Dragon and CST-100 will launch from Florida's Space Coast. The first manned mission is scheduled for 2017.
