...is for carrying the Altair lunar lander and anything else destined for the surface of the moon, such as a pressurised 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 is 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 100km 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, although the details are not yet pinned down. 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 on 18 June.
First is the Lunar Reconnaissance Orbiter (LRO), which has begun mapping the lunar surface from the very low elevation of 50km, 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 on 9 October, 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 analyse the position and visibility of the plume.
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 is 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 will 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."
