Photo courtesy Lockheed Martin
The VentureStar could become the mass transit system for Earth-to-orbit travel.
Take a peek at NASA's drawing board and you're bound to see amazing plans for giant, lightweight solar sails that will take us far beyond the edge of our solar system, and space elevators that will allow us to zip in and out of orbit whenever we like. Long before those plans are realized, you will see the latest members of NASA's X-fleet spaceships, which could make space a vacation destination within the first two decades of this century.

Since the beginning of the American space program, the X-planes have been the test models for space technology. Currently there are several experimental X-plane models in development that could make space travel as routine as airplane travel. Each of these latest X-planes are reusable launch vehicles (RLVs), like the space shuttle, which means that they can be launched into orbit repeatedly before being replaced.

These lightweight vehicles are designed to lower launch costs, and could eventually replace the space shuttle, which has been in use since 1981. Commercial space travel remains prohibitive because of the expense: It costs about $10,000 to get one pound (.45 kg) of payload into Earth's orbit. Space planes could lower that price to $1,000 per pound. In this edition of How Stuff Will Work, you'll find out about some of the space planes being developed by NASA, and how these spacecraft might one day succeed the space shuttle and be used as commercial vehicles for space tourism.