None of these plans went anywhere, of course. "There were a number of years where 'exploration' was a dirty word at the agency," Connolly says.
Then came the 2003 Columbia accident, and a dramatic, White House-mandated change of course. No more circling Earth. Returning people to the moon, and using it as a training ground for Mars, would be the space agency's new plan. So for the past two years, Connolly and his colleagues at NASA headquarters have been developing the Architecture (a word NASA uses with the same reverence fundamentalists accord to "Scripture") for accomplishing their new mission.
The Architecture calls for sending four astronauts at a time to the lunar surface, compared with Apollo's two. Instead of spending three days on the moon, they'll stay a week. And rather than being confined to a narrow band of landing sites around the lunar equator, they'll be able to land anywhere, even the poles, where scientists believe ice in the soil could be converted to fuel and drinking water.
These improvements over Apollo result largely from an advantage in rocket power. Not only are modern propulsion systems more efficient than those of 40 years ago, but NASA is also taking a different approach this time, launching the moon vehicles on two separate rockets with a combined 150 metric tons of lift. In comparison, Saturn V had 130 tons.
LSAM's additional lift power will enable it to be bigger, better, and in every way more capable than its predecessor. In cargo-only mode, with no crew, its carrying capacity will be 21 tons, more than the weight of the entire LM.
But will it look very different? No matter how many years have passed or how many studies have been conducted, the physics and engineering practicalities of landing on the moon drive the design inexorably toward what the Grumman engineers came up with decades ago. "We might have wanted the LSAM to look like the Millennium Falcon," says Connolly, with a trace of wistfulness. "But it will probably look like the Apollo LM."
The best way to do lunar exploration would be a "direct-direct" option, straight from Cape Canaveral to the surface of the moon. But that requires a rocket that can lift 200 tons to Earth orbit, says Connolly, and "we're just not going to build a launcher that big."
The LSAM lander will go on a large rocket, along with the Earth departure stage needed to reach the moon. A smaller rocket will then deliver the crew (in an Apollo-style capsule called the Crew Exploration Vehicle) to Earth orbit. There the CEV and LSAM will link up, the departure stage will fire, and three days later the still-joined vehicles will enter a 60-mile-high lunar orbit, from which the LSAM will descend to the moon's surface. NASA calls this big rocket-small rocket combo its "1.5 launch" option.
The study team quickly settled on a two-stage lander, same as that in Apollo, with a descent stage topped by a smaller ascent stage that brings the crew back up to lunar orbit following their adventures on the surface. In orbit, they'll return to the CEV capsule for the journey home.
Here the new plan again diverges from the old one. There will be no Mike Collins waiting in lunar orbit to greet Neil and Buzz -- the CEV will be left unattended.