NASA has bold plans to explore the final frontier - again.

AS YOU READ THIS, astronauts in the International SpaceStation (ISS) are circling the earth every 90 minutes. NASA isbusily preparing to relaunch the space shuttle fleet. And more thana dozen robotic NASA spacecrafts are exploring our neighborhood inthe Milky Way: Cassini-Huygens spacecraft photographing Saturn'smoons, the rovers poking around Mars, and the venerable Voyagersinvestigating the edge of our solar system. Important stuff, to besure. But what about all that new-millennium, gee-whiz spaceexploration that seemed so promising when an astronaut was hittinga golf ball on the moon decades ago? Whatever happened to a futureof Capt. James T. Kirk, phasers set on stun, and humans living onthe moon?

Where, exactly, is the U.S. space program heading?

Since 1972, hundreds of people have
been to space, but no one has gone beyond orbiting Earth, about 200miles from our planet. NASA is now making committed moves to getearthlings beyond that realm again. Commercial companies andnonprofits also are looking to stake claims in a new era ofexploring the final frontier.

If you listen to the enthusiasts and scientists who relish defyinggravity, that's just the beginning. Our future in the cosmos couldinclude humans plasma-rocketing to Mars, NASA vehicles dodgingspace elevators that rise 62,000 miles high, human colonies on themoon that harvest oxygen from rocks, and giant sails coasting onsunlight to Pluto.­ Here are some of these plans.


NASA's human-transport plans are both futuristic and retro. John Connolly was a deputy for the group that was given a 90-day challenge in the summer of 2005 to create a new vehicle for getting humans to the moon and to Mars. "We went back to documents that were written in the 1960s, and we had a blue-ribbon group of folks who walked on the moon to help," he says. "Subconsciously, we really didn't want this to look like Apollo.­ We wanted it to look like our generation's spacecraft, our trip to the moon. But after three months of study, we learned that it's the physics that basically shape what the vehicles look like." NASA administrator Michael D. Griffin calls it "Apollo on steroids," referring to the greater size and expanded capacities of the new vehicle.

Much of the system will rely on recycled shuttle engines and tanks. A futuristic difference for a return to the moon may be the fuel sources. "Eighty percent of the mass you land on the moon is your rocket fuel to get home," says Connolly. "If you could manufacture a fraction of that, there's an incredible economy."

Once on the moon, "there are chemical ways of cracking the oxygen out of the moon dirt, which is called regolith. It's ground-up rocks, really," Connolly says. "We've actually done experiments using real lunar samples that the astronauts brought home in the '60s, and we've proved in the laboratory that it can be done." He is also optimistic about producing methane on Mars, which would provide another good rocket-fuel component.

In theory, he says, "You could manufacture all the oxygen you'd need to breathe, all the water you'd need to drink, and all the fuel you'd need to get you home."