For the first time since 1972, the United States is planning to fly to the moon, but instead of a quick, Apollo-like visit, astronauts intend to build a permanent base and live there while they prepare what may be the most ambitious undertaking in history — putting human beings on Mars.
President Bush in 2004 announced to great fanfare plans to build a new spaceship, get back to the moon by 2020 and travel on to Mars after that. But with NASA focused on designing a new spaceship and spending about 40 percent of its budget on the troubled space shuttle and international space station programs, that timetable may suffer.
Still, NASA's moon planners are closely following the spaceship initiative and, within six months, will outline what they need from the new vehicle to enable astronauts to explore the lunar surface.
"It's deep in the future before we go there," said architect Larry Toups, head of habitation systems for NASA's Advanced Projects Office. "But it's like going on a camping trip and buying a new car. You want to make sure you have a trailer hitch if you need it."
Scientists and engineers are hard at work studying technologies that don't yet exist and puzzling over questions such as how to handle the psychological stress of moon settlement, how to build lunar bulldozers and how to reacquire what planetary scientist Christopher P. McKay of NASA's Ames Research Center calls "our culture of exploration."
A lethal place
The moon is not for the faint of heart. It is a lethal place, without atmosphere, pelted constantly by cosmic rays and micrometeorites, plagued by temperature swings of hundreds of degrees, and swathed in a blanket of dust that can ruin spacesuits, pollute the air supply and bring machinery to a screeching halt.
And that says nothing about the imponderables. Will working in one-sixth of Earth's gravity for a year cause crippling health problems? What happens when someone suffers from a traumatic injury that can't be treated by fellow astronauts? How do people react to living in a tiny space under dangerous conditions for six months?
"It's like Magellan. You send them off, and maybe they come back, maybe they don't," said planetary scientist Wendell W. Mendell, manager of NASA's Office for Human Exploration Science, during an interview at the recently concluded Lunar and Planetary Science Conference here. "There's a lot of pathologies that show up, and there's nobody in the Yellow Pages."
Harder than Mars
In some ways, the moon will be harder than Mars. Moon dust is much more abrasive than Mars dust; Mars has atmosphere; Mars has more gravity (one-third of Earth's); Mars has plenty of ice for a potential water supply, while the moon may have some, but probably not very much.
Still, the moon is ultimately much more forgiving because it is much closer — 250,000 miles away, while Mars is 34 million miles from Earth at its closest point. If someone needs help on the moon, it takes three days to get there. By contrast, Mars will be several months away even with the help of advanced — and as yet nonexistent — propulsion systems.
Not having to pay as dearly for mistakes is one key reason why the moon is an integral part of the Bush initiative. The other, as even scientists point out, is that if the United States does not return to the moon, others will.
"The new thing is China, and they've announced they're going to the moon. The Europeans want to go; the Russians want to go; and if we don't go, maybe they'll go with the Chinese," Mars Institute Chairman Pascal Lee said in an interview. "Could we bypass the moon and go to Mars while India and China are going to the moon? I don't think so."
Bush's 2004 "Vision for Space Exploration," by calling for a lunar return and a subsequent Mars mission, set goals, which, if achieved, would keep the United States in the forefront of space exploration for decades.
Since then, mishaps and delays with the space shuttle and the space station programs have shrunk both the moon research budget and the rhetoric promoting the mission.
Instead, NASA Administrator Michael D. Griffin has focused agency attention and resources on the design and construction of a new "crew exploration vehicle" and its attendant rocketry — the spacecraft that will push U.S. astronauts once again beyond low Earth orbit.
Despite the moon's current low profile, however, NASA continues to plan a lunar mission and to promote the technological advances needed to achieve it. Toups, one of the moon program's designers, said NASA envisions that a lunar presence, once achieved, will begin with two to four years of "sorties" to "targeted areas."
These early forays will resemble the six Apollo lunar missions, which ended in 1972. "You have four crew for seven to 10 days," Toups said in a telephone interview. "Then, if you found a site of particular interest, you would want to set up a permanent outpost there."
The south pole is currently the top target. It is a craggy and difficult area, but it is also the likeliest part of the lunar surface to have both permanent sunlight, for electric power, and ice, although many scientists have questions about how much ice there is. Without enough water, mission planners might pick a gentler landscape.
Site selection will mark the end of what McKay calls Apollo-style "camping trips." "There's got to be a lot more autonomy, so we keep it simple," McKay said. "We're going to be on Mars for a long time, and we have to use the moon to think in those terms."
The templates, cited frequently by moon mavens, are the U.S. bases in Antarctica, noteworthy for isolation, extreme environment, limited access, lack of indigenous population and no possibility of survival without extensive logistical support.
"The lunar base is not a 'colony,'" Lee said. "'Colonization' implies populating the place, and that's not on the plate. This is a research outpost."
Technologies yet to be found
Once planners choose a base, the astronauts will immediately need to bring a host of technologies to bear, none of which currently exist. "Power is a big challenge," Toups said. Solar arrays are an obvious answer, but away from the poles 14 days of lunar sunlight are followed by 14 days of darkness, so "how do you handle the dormancy periods?"
Next is the spacesuit. Apollo suits weighed 270 pounds on Earth, a relatively comfortable "felt weight" of 40 to 50 pounds on the moon, but an unacceptable 102 pounds on Mars. "You can't haul that around, bend down or climb hills," Lee said. "Somehow we have to cut the mass of the current spacesuit in half."
And the new suit, unlike the Apollo suits or the current 300-pound shuttle suit, is going to have to be relatively easy to put on and take off, and to be able withstand the dreaded moon dust.
After three days, Apollo astronauts reported that the dust was causing the joints in their suits to jam, "and we're not talking about three outings," Lee said of the next moon missions. "We're talking about once a week for 500 days — between 70 and 100 spacewalks."
Back to the 19th century?
Dealing with dust is also a major concern in building shelters on the lunar surface. Toups said it might be possible to harden the ground by microwaving it, creating a crust "like a tarp when you're camping." Otherwise, the dust pervades everything, and prolonged exposure could even lead to silicosis.
Dust also makes it virtually impossible to use any kind of machinery with ball bearings. Civil engineer Darryl J. Calkins, of the Army Corps of Engineers Cold Regions Research and Engineering Laboratory, warned that the combination of dust, low gravity, temperature swings and the high cost of flying things to the moon is going to define the lunar tool kit in unforeseen ways.
"You can't put a diesel up there; you can't put a 20,000-pound bulldozer up there; and none of our oils or hydraulic fluids are going to survive," Calkins said in a telephone interview. "We may have to go back to the 19th century to find appropriate tools — use cables, pulleys, levers."
And even then, it will be difficult to level a base site and haul away the fill because there's not enough gravity to give a tractor adequate purchase. Instead, Calkins envisions a device that can "scrape and shave" small amounts of soil and take it away bit by bit.
But in the end, "you have to learn how to do it, with real people," McKay said. "This is hard, but we can learn it. And if we do it right on the moon, we will be able to answer my ultimate question: Can Mars be habitable? I think the answer is 'yes.'"