CST-100

[Image credit: Boeing, PDF]

Boeing's entry into the commercial crew and cargo program is the Crew Space Transportation-100, or CST-100 for short. In addition to shuttling astronauts to the International Space Station, it's intended to carry folks to private space stations like those proposed by Bigelow Aerospace. When it's tasked with taxiing humans, Boeing's vessel can carry a crew as large as seven.

For landings, the craft slows itself down with parachutes and touches down on terra firma. In the case of an emergency, however, the vehicle can take a dip in the sea.

The CST-100 isn't quite ready to be tossed into the vacuum of space quite yet, but it's making good progress. In February, the hardware that connects it to Atlas V rockets passed muster with NASA, and it's on track to hit the development milestones the space agency is looking for in 2014.

CST-100 Diameter 4.56 m (15 ft) Height 5 m (16.5 ft) Weight Approx. 9,000kg (20,000 lbs) Crew (maximum) 7 Launch Vehicle(s) Atlas V, Delta IV and Falcon 9

Dream Chaser

[Image credit: NASA]

The odd duck in the government's commercial crew program is the Dream Chaser. Rather than rely on a capsule design, Sierra Nevada Corporation's built its astronaut taxi by picking up the space shuttle's mantle. Although it resembles NASA's retired 184-foot long workhorse, it measures up at just 29.5 feet long. Not only does it look like a pint-sized shuttle, but it also functions much like one.

The Dream Chaser uses an entirely different form of controlled descent from its competition. By gliding down from low-Earth orbit, the contraption is able to land at any airport runway suited for commercial airliners. While it builds on the shuttle's strengths, it also inherits some of its weaknesses. Sierra Nevada's solution can handle ferrying up to seven folks to space in low-earth orbit, but it's not fit for long trips to other planets.

In November of 2016, the pint-sized shuttle lookalike is scheduled to make it to orbit for the first time. As if the similarities to NASA's spaceplane weren't enough already, it's set to use the very same runway (for landing) as its much larger doppelgänger.

Dream Chaser Length 9 m (29.5 ft) Wingspan 7 m (22.9 ft) Weight 11,300 kg (25,000 lbs) Crew (maximum) 7 Launch Vehicle Atlas V

Orion

[Image credit: NASA, Flickr]

OK, NASA's next-generation space vehicle, Orion, isn't a commercial craft, but it's certainly worth mentioning. Although it was originally devised as part of the now-canceled Constellation program that aimed to take astronauts to asteroids, Mars and the moon, the space agency's building a version of the craft -- with the help of Lockheed Martin -- that'll become its Swiss Army knife. Now dubbed the Orion Multi-Purpose Crew Vehicle (MPCV), it'll be able to make those same trips using a new rocket setup called the Space Launch System. What's more, it'll also be able to haul up to six people to the International Space Station if the need arises.

Returning to Earth for Orion means deploying parachutes and splashing down in the ocean, much like the Apollo missions did. In an emergency, however, the vessel can safely set itself down on soil.