Still in the works

Several companies are hard at work designing, building and testing vehicles that aim to fill the American gap in human spaceflight following the retirement of NASA's space shuttle program. These commercial providers hope to carry astronauts to the International Space Station, but could also one day transport other paying customers to the space station and future destinations in low-Earth orbit.
Boeing, SpaceX, Blue Origin and Sierra Nevada are developing and testing vehicles and launch systems as part of NASA's Commercial Crew Development (CCDev) program.