Forty years after the first humans walked on the moon, NASA is trying again to reach the Earth's nearest celestial neighbor.
It's not just about retracing 40-year-old footsteps in the lunar dust, though. This time, NASA wants its moonshot to become an outpost and eventually a Mars shot too, if Congress and others can be persuaded to part with the necessary money.
The new attempt is well past the idea stage. Two spacecraft are freshly launched on scouting missions to map the moon and see whether permanently shaded areas in craters on its south pole really do contain ice, a substance that could make living on the moon vastly easier and that could in theory even be turned into new rocket fuel.
And, with a program called Constellation now in its third year, NASA wants to land people on the moon in 2020 and then create an outpost--a "toehold on the frontier," according to John Connolly, head of engineering for the bigger Altair lunar lander.
It might well be that overcoming the Earth's gravity is easier than overcoming the financial constraints of a nation in economic recession.
"Given the current budget, if nothing changes, it's going to be very challenging" to meet the goal of reaching the moon by 2020, said John Olson, director of NASA's Exploration Systems Mission Directorate Integration Office.
The current budget plan is uncertain: the Obama administration in May ordered a review of human space-flight programs that considers the goal of "fitting within the current budget profile for NASA exploration activities."
Why go back?
There's no more Cold War race spurring the National Aeronautics and Space Administration to outdo the Russians, but the overall reason to go to the moon and beyond remains the same: inspiration and science.
"The most important attribute we got out of Apollo is it taught us nothing was impossible," Olson said of the first trips to the moon. Monday will mark the 40th anniversary of Apollo 11's lunar landing.
The new program, with aspirations to bring people not just to the moon but also Mars and the asteroids, is "motivating the next generation of students and researchers and engineers and scientists," Olson said.
NASA also takes pains to point out its economic influences--jobs, spinoffs, and money infused in the country's industrial base. The agency is seeking a 6 percent budget increase to $19.3 billion for fiscal 2010, Olson said. Elements of the Constellation program are under way in 11 states.
What's got Larry Taylor excited, though, is that "scientifically, there's a lot to learn." A former NASA geologist who worked on the Apollo missions and now a professor at the University of Tennessee in Knoxville, Taylor is interested in questions about the origins of the moon--the history of massive impacts and upwellings of the moon's initially molten interior during the early years of the solar system. Prevailing opinion today holds that the moon was a byproduct of a Mars-sized object hitting Earth in the solar system's more turbulent beginnings.
These reasons weigh against the fact that it's expensive to get to the moon.
"You're not going to see any moon mission in my opinion," predicted Charles Pellerin, who as NASA's former director of astrophysics led the Hubble Space Telescope project. "The price to go back to the moon is probably at least a doubling of NASA's budget."
He prefers robotic exploration to human exploration. And if he controlled NASA's purse strings, he'd spend the budget to study the science behind the Earth's climate, the origins of life, and new physics informed by investigation of the universe's distant past. The Hubble showed visible light from far away--and therefore long ago--but he'd like to see the same views in X-ray, gamma ray, and infrared light.
"There are phenomena throughout the universe that have physics you can't even conceive of on the Earth," Pellerin said. "Quasars release more energy in one second than the sun does in 30,000 years. How's that work?"
How do we get there?
But of course a lot of folks can get more excited about humans exploring than about astrophysics, and it's for them that NASA likes to send people into space. So how does the new and improved moon program work?
The same way the old one did, in part. "The physics of moving around the solar system hasn't changed," Connolly said. But there are many significant differences from the grander aspirations.
"We designed the transportation system so we could fly folks to Mars eventually," Connolly said. Chiefly, that means that the system can lift more mass into space, whether to build a lunar outpost or to head to Mars.
To lift more weight, there are two rockets, Ares I and V, instead of Apollo's one rocket. The smaller Ares I is designed to carry the crew--as many as six, four of whom can land on the moon. The more powerful Ares V is for carrying the Altair lunar lander and anything else destined for the surface of the moon, such as a pressurized vehicle or a lunar dwelling.
The two rockets' contents will be united in orbit around the Earth, then the cargo in the tip of the Ares V, called the Earth departure stage, will carry the crew and lander to the moon, according to the plan. As with Apollo, the lander will make the descent to the moon while some crew remain above in an orbiter.
The lander itself looks as awkward as the original Apollo landers, including the four splayed legs. But it's bigger, with enough resources to keep four people on the lunar surface for a full seven days, compared to two for Apollo.
On the way back, the bottom half of the lander stays put on the moon while the ascent stage docks with the orbiter in orbit about 100 kilometers above the lunar surface. The crew is reunited, the ascent stage is discarded, and the crew return to Earth, eventually plunging through the atmosphere in a conical capsule
For Mars, things get more complicated, though details are not pinned down yet. The lunar missions are designed to let engineers work out the issues. Even under the optimistic schedule, a Mars return is set tentatively for 2030.
Meanwhile, in 2009
NASA's present work is designed to lay the groundwork for a manned moon mission with two spacecraft that were launched June 18.
First is the Lunar Reconnaissance Orbiter (LRO), which has begun mapping the lunar surface from the very low elevation of 50 kilometers, or about 31 miles. NASA plans to release its first images of proposed landing sites on Friday.
But the rocket could carry a little more payload, so piggybacking on the trip is the second craft, the Lunar Crater Observation and Sensing Satellite (Lcross). This craft will come to a deliberate and dramatic end October 9, when first the Centaur rocket that carried it and the LRO to the moon smashes into a crater at a speed of 1.55 miles per second, then Lcross itself follows shortly after.
Lcross sports three cameras, said Rusty Hunt, one of the mission's flight directors, to closely watch the debris from when the 5,200-pound, 41-foot Centaur rocket hits the moon. NASA expects a plume 6.2 miles high, and Lcross will send a real-time stream of observational data to Earth.
Various Earth-bound telescopes and the Hubble will watch the plume, too. And because the plume will be visible from Earth with modestly powerful telescopes, NASA hopes amateur astronomers will send in their own photographs to help analyze the position and visibility of the plume.
So why the south pole?
The Apollo missions landed on the moon's equatorial regions, a navigationally simpler task. But there are good reasons to visit the polar reasons when it comes to human habitation resulting from the fact that some rises are in permanent sunlight and some crater interiors are in permanent shade.
Scientists have found the physical signature of hydrogen in the polar regions, leading them to believe it's possible there is ice hidden in the shade. The ice, likely the leftovers of eons of comet impacts, is useful for human consumption and, more grandly, for producing rocket fuel by splitting it into the liquid oxygen and liquid hydrogen that are today's rocket propellant of choice. And, of course, oxygen is necessary for breathing.
"If we can find water, it greatly enhances our ability to set up a long-term outpost or permanent moon base," Hunt said. Scientifically, "it'll help to fill in gaps about the early evolution of the moon and the earth-moon system and solar system if we can say yes, indeed, there's water there."
Lunar high ground on the polar regions benefit from permanent sunlight, too. That makes for an easier, balmier climate and means rotating solar panels can track the sun at all times with ease, Connolly said.
August panel results
The present moon missions stem from an initiative former President George W. Bush outlined in 2004. Five years later, LRO and Lcross show some evidence that NASA is making progress.
The budgetary hurdles are formidable. The first clues about funding are scheduled for August, when the head of the Obama administration's human space-flight review, retired Lockheed Martin chief executive Norm Augustine, presents his panel's options.
In the long run, though, Olson is optimistic not only about revisiting the moon, but making it to Mars, too.
"I don't think we're yet ready from fiscal or technical capability to go to Mars," Olson said. "But I'm confident we'll eventually get there."