A new flight plan: back to the moon

Science News, March 13, 2004 by Ron Cowen

And then there's the decision to eliminate any further shuttle missions to repair or upgrade the Hubble Space Telescope. Without maintenance, that orbiting telescope could stop functioning as early as 2006 instead of lasting into the next decade.

NASA administrator Sean O'Keefe says that his decision was based solely on safety issues. However, Rodger Thompson of the

University of Arizonain Tucson and some other astronomers contend that the real reason for cutting Hubble short is to save money for the moon-Mars initiative.

"I'd love to go to Mars," says Thompson, but an early demise of Hubble "is a pretty high price to pay today for a program that may never get funded."

MARS TEST BED The President's plan has people living and working on the moon for extended periods "If we can develop a closed life support system on the moon, then we'll be able to do the same thing at least as easily on Mars," says Duke.

As a dress rehearsal for investigating the Red Planet, lunar explorers would build a base, assemble a filling station, and learn how to manipulate fragile grains of material for scientific analysis. The advantage, of course is that the moon is just 3 days away, while traveling to Mars could be a nearly yearlong sojourn.

However, the demonstration site may provide obstacles that Mars visitors would never encounter. The moon lacks the shield provided by even a thin planetary atmosphere, such as Mars, so lunar explorers will have to withstand the relentless bombardment of harmful solar radiation and pelting rain of micrometeoroids. Despite its windstorms, Mars might turn out to be a more hospitable place because it has more water and other essential materials, says Duke.

If it's to build upon astronauts' lunar experience, a human mission to Mars must follow sooner rather than later, says Garvin. Bush's plan doesn't specify when the journey to the Red Planet might occur.

But NASA shouldn't delay another 20 years beyond 2020, the target for returning to the moon, says Garvin. If the agency waits too long, he cautions, "then all the technology lessons learned from the moon will be lost."

RELATED ARTICLE: NASA's nuclear legacy: using fission to journey to the red planet.

For many space enthusiasts, sending people to Mars has long been the ultimate dream. President George W. Bush, in his new space-exploration plan, doesn't specify a date for a human journey to the Red Planet. But some space scientists hold that much of the technology is ready to roll.

Shortly after Neil Armstrong's historic moon walk in 1969, NASA rocket scientist Wernher Von Braun told a House of Representatives science committee that the space agency would be ready to fly people to Mars by 1981. Braun based his prediction on research NASA had been conducting since the early 1960s on using nuclear reactors to propel spacecraft into deep space.

In 1961, NASA and the Atomic Energy Commission founded the Nuclear Engines for Rocket Vehicle Applications (NERVA) program. The NERVA design for rockets was relatively simple. A nozzle would be attached to a reactor in which the fission of uranium-235 releases tremendous amounts of heat. Liquid hydrogen would flow around the reactor, absorbing heat and vaporizing. That would provide a propulsive force as the hydrogen rushes out the nozzle.