The ORION capsule
The Orion space craft is a design throwback to the Apollo style splashdown capsules. These teardrop shaped capsules are placed on the tip of a rocket and launched into orbit on an Ares V rocket.
Orion is part of the Constellation class crew vehicles. The Apollo shaped vehicle is the best understood design for reentry and splashdown. But perhaps the greatest driving force for the Orion vehicle is that its design allows for an emergency separation of the crew vehicle during an orbital injection procedure. In other words, NASA scientisits believe it will kill less astronauts during launch.
The capsule is 5 meters wide and masses about 25 tons. This design will enable NASA to begin preparations for moon landings, constructing a moon base, and beginning construction on low-Earth-orbital space docks for construction of craft to visit Mars.
Unfortunately, the Orion craft will not be ready until 2013. So that leaves a gap between the shuttle retirement and the beginning of Orion's mission of nearly 4 years. Meanwhile the International Space Station still needs to be manned by American astronauts, experiments performed on the ISS, and construction of other space enterprises in orbit. So how will America keep its access to space during this gap?
NASA plans to use the Russian Soyuz capsules in accordance with the Russian space program. The Soyuz capsules have been used by Russia for a very long time and have proven to be reliable and efficient, if a bit small. One concern that was presented about the Soyuz is its ballistic reentry, but NASA seems to believe that if the Cosmonauts can do it, so can American astronauts. there are of course other political concerns, but the fear that the Chinese heavy-lift capacity will get them to the moon sooner is driving both the US and Russia to combine forces to reach there first in a new sprit of cooperation.