Spacecraft Alternatives
{{#rendered}} {{/rendered}}An artist's impression of Orbital Sciences' Cygnus capsule approaching the International Space Station. (Orbital Sciences Corporation)
SpaceX's Falcon 9 rocket during a test at Cape Canaveral, Fla. (Space Exploration Technologies Corp.)
A composite image showing an Orbital Sciences Taurus II rocket on the launch pad at the Mid-Atlantic Regional Spaceport on Virginia's Eastern Shore. (Orbital Sciences Corporation)
An artist's view of SpaceX's Dragon capsule in orbit. (Space Exploration Technologies Corp.)
A night shot of the Falcon 9 rocker on the launch pad at Cape Canaveral, Fla. (Space Exploration Technologies Corp.)
An artist's impression of an Orbital Sciences Taurus II rocket blasting into space. (Orbital Sciences Corporation)
An artist's illustration of what would have been Rocketplane Kistler's K-1 rocket. (NASA)
A full-scale mock-up of a SpaceX Dragon crew capsule on display during the 2007 X-Prize Cup at Holloman Air Force Base, N.M. (Wikimedia Commons)
An aerial photograph of the Mid-Atlantic Regional Spaceport and NASA's Wallops Flight Facility on Virginia's Eastern Short. (NASA)
An artist's illustration of a DC-X reusable launch vehicle lifting off. (NASA)
A full-scale mockup of the HL-20 lifting-body spacecraft, still seen by some as a possible replacement for the space shuttle. (NASA)