] Developing a new space plane in five years is a very
] short timetable. It took more than 10 years to get the
] shuttle flying. But the idea behind the new space plane
] is to make it simple, small and reliable, and not to
] break too much new technological ground.

If they have a conservative enough design, it is absolutely possible to do this ... but I expect NASA will probably drop the ball anyway...

WESH.com - News - NASA Works To Build New Spaceship