Now that the U.S. space shuttle program has ended, NASA is turning to the private sector for the next generation of reusable manned spacecraft—including the Sierra Nevada Corporation's Dream Chaser (illustrated above).
The brainchild of the Colorado-based Sierra Nevada Corporation, the Dream Chaser is one of five private-spacecraft proposals that won U.S. $50 million in federal grants under the 2009 American Recovery and Reinvestment Act.
The proposed new shuttle's primary mission is to transport cargo and up to seven astronauts to the International Space Station, and to return crews safely to Earth, according to Sierra Nevada's website.
Among Dream Chaser's advantages: It's designed to launch on top of Atlas rockets, which have been reliably used by NASA since 1957.
Last month Sierra Nevada was awarded an additional $213 million grant—along with $440 million to SpaceX and $460 million to Boeing Corporation—to continue plans that, NASA said, would set the stage for "demonstration missions to low-Earth orbit by the middle of the decade."
—Richard A. Lovett
Illustration courtesy SNC Space Systems
Competing spacecraft designs must pass safety and reliability tests, as shown in this picture of the Dream Chaser concept undergoing structural testing.
The goal of supporting private manned spacecraft is to bridge the "spaceflight gap" left by the retirement of the shuttles—and to allow the space agency to focus on longer-range missions, such as sending rovers to Mars, NASA has said.
The hope is that NASA astronauts will soon be able to buy tickets to space in much the same way the rest of us buy airline tickets.
It's an exciting era, said David Brin, a science fiction writer who holds a Ph.D. in space science from the University of California, San Diego.
"Ever since Challenger blew up [in 1986], NASA's approach has been to redouble caution," added Brin, who applauds the risktaking ethos he sees among the private-shuttle contenders.
SpaceX's unmanned Dragon spacecraft is corralled by the International Space Station's robotic arm on May 25. The flight proved that the reusable Dragon, which can be reconfigured to carry a crew, can deliver cargo to the space station—the first commercial spacecraft to do so.
Despite its pioneering mandate, Dragon lands the old-fashioned way, with an Apollo-style splashdown.