NASA’s Orion space vehicle is scheduled to make its first (unmanned) flight on December 4th. Like most first flights, it’s objectives are fairly modest. Toss it up, make a couple orbits, come back down. The one really aggressive move it will be making is that the orbits will be highly elliptical, with a maximum altitude of about 3,600 miles. That the highest orbit for a man rated vehicle in about 40 years.
Why do this? Because Orion is not simply designed for low earth orbit, but rather for deep space exploration, potentially lunar or even Mars orbital missions. When you return from lunar flight, the reentry speed is much, much greater than from simple low earth orbit.
Not only will Orion use its power to achieve a higher orbit, it will use its engines to artificially accelerate to mimic that higher reentry speed. A similar test was done during the Apollo program.
Here’s a look at the first quarter 2014 progress report.