NASA hopes to open a competition this winter for a new cryogenic upper stage and related hardware that, when combined with a single space shuttle solid rocket booster (SRB) and the Crew Exploration Vehicle (CEV) already in development, will form the basis for a new generation of vehicles that could transport humans to Mars in 25 years.

Administrator Michael D. Griffin wants to combine shuttle parts like the SRB and operational concepts dating back to the Apollo program to shift the space-exploration course set 35 years ago to one that will last at least another 35. But with barely three years remaining in the presidential administration of the man who hired him, it won't be easy.

To get his agency--and humankind--on the tack President Bush set on Jan. 14, 2004, with the post-Columbia "vision for space exploration," Griffin plans to start a process in the next few weeks that will see an orderly transition from the shuttle to the shuttle-derived Crew Launch Vehicle (CLV) by 2012, at the latest. Limited by the funds available rather than by technical hurdles, NASA would then use the new CLV and four-seat CEV--hopefully in conjunction with commercial cargo launchers--to service and staff the International Space Station.

MEANWHILE, SPENDING money freed by the shuttle's retirement in 2010, the U.S. space agency would start developing a much larger rocket assembled from shuttle components that would take four astronauts to the surface of the Moon by 2018, and eventually lift the first human Mars mission for assembly in low Earth orbit. The plan would make maximum use of the expertise gained flying the shuttle and assembling the ISS, as well as ground infrastructure dating back to the Apollo era.

But to get started, Griffin must navigate tricky political, technical and managerial waters that will exercise to the utmost the experience he has gained as a Washington-based spaceflight expert over the past 30 years. Congress returns this week for the first time since the shuttle Discovery completed its post-Columbia shakeout mission, and the White House has yet to sign off on all the details of the program Griffin will present on Capitol Hill.

By the end of this year, Griffin and his colleagues must sell the White House and Congress their plans for managing the transition from shuttle to CEV, and for the architecture that will get U.S. astronauts to ISS and the Moon. With midterm elections a little more than a year ahead, they must mollify the political and scientific constituencies whose programs will be cut to fund the new efforts, and convince a skeptical public that NASA hasn't lost the technical skills that took it to the Moon the first time.

"This is a big month coming up for us," Griffin said in an Aug. 25 interview. "We expect there'll be a lot of newsmaking events over the next month."

Since he took office on Apr. 18, Griffin has overturned much of the "spiral development" work initiated under his predecessor to implement the president's exploration program. In place of casting a wide net for technology with standing-room-only exploration workshops and plans for a fairly lengthy parallel CEV development by competing contractors, Griffin and his relatively small management group have largely worked behind the scenes. From there, they have drafted their view of the exploration architecture and the "improvements" to the CEV proposals they want from the two contractors competing to build it--Lockheed Martin and a Northrop Grumman/Boeing combination.

"We don't have an infinite amount of money," he says. "What we have is a specific task we're trying to perform, and I'm trying to do that in the simplest, cheapest, easiest, most prudent way possible, and that's at the root of my preference for shuttle-derived architectures. I'm also trying not to waste the cadre of manned spaceflight experience that exists out there in the workforce today. So when we talk about retiring the shuttle, we're really talking about retiring the shuttle orbiter."

As required by Bush's space transportation policy, Griffin has worked a deal with the U.S. Air Force to use the Atlas V and Delta IV Evolved Expendable Launch Vehicles (EELVs) "to the maximum extent possible" for unmanned civil missions requiring lift of up to 20 metric tons. That spreads the EELV cost around the government, while giving NASA freedom to develop its two shuttle-derived vehicles for its unique exploration missions.

Those vehicles have been pushed for more than a year by ATK Thiokol, builder of the SRB, and others as a quick and relatively inexpensive way to get human-rated rockets ready for the post-shuttle era (AW&ST June 28, 2004, p. 26). The new upper stage will also be needed for EELV cargo missions to the ISS, Griffin says, but he remains "agnostic" on issues of the stage design and the human-rated engines that have been suggested to power it.

"The J-2 Apollo-Saturn engine was a great engine, and certainly the nation can go restart that production line and build that engine again," he says. "The shuttle main engine is a great engine. We would need a production version of it instead of one that was designed for substantial reuse, but that's a great engine. And what choice at the engine level that we make depends on the outcome of the trades that people are working on."

Griffin says the "single-stick" SRB-derived Crew Launch Vehicle could also be used to carry cargo to the ISS. But he reiterates his plan to make about $500 million available in the NASA budget to buy commercially developed cargo-delivery services for the station (AW&ST June 27, p. 24). NASA is also considering an investment fund--currently dubbed Red Planet--that would provide seed money for advanced exploration technology development, like the CIA-backed In-Q-Tel fund where Griffin once worked as president and chief operating officer.

Despite the plans for continued station support, NASA's ISS partners are worried the U.S. will retire the shuttle fleet before it finishes launching and assembling the station components that were tailored to shuttle capabilities. Their concern only increased after continued foam-shedding during the shuttle's return-to-flight ascent in July forced NASA to push the next flight back to March 2006 at the earliest (AW&ST Aug. 22/29, p. 26).

Griffin reiterates what NASA has been saying since the Columbia accident and subsequent investigation: Every shuttle flight remaining will be a test flown with much more care and attention to engineering detail than was the case on Columbia's last mission. But, he argues, most of the big pieces remaining can be added to the station before the shuttle retires.

"WE THINK WE can fly out the shuttle program and use the shuttle to assemble the station even with this very careful, very disciplined approach to flying the shuttle," he says. "And if we get to the end and we have a thing or two to still be put up with the new system, then that's what we'll do."

Once the station is complete and the shuttle retired, NASA plans to begin work on the heavy-lifter that will be needed to take humans back to the Moon and on to Mars. It must be able to take at least 100 metric tons to low Earth orbit.

"You can argue about what the second digit is, but the first one is clearly 100," he says.

With that capability--formed by removing the shuttle orbiter and using the remaining boosters, external tank and cryogenic engines to form an in-line stack with the payload on top--Griffin and his team believe they can launch a four-person mission to the Moon. Drawing on Apollo concepts, they would use a combination of Earth- and lunar-orbit rendezvous, leaving the CEV in lunar orbit while its entire crew explores the surface below. Their concept would also place the lunar poles, where water ice may exist in the permanent shadow of deep craters, within range of human explorers.

That development will be paced by the funds NASA hopes will be available once the shuttle orbiter is retired. Griffin says his team's plans include a 20% reserve, and can be achieved for the funds expected if development of the lunar vehicles is deferred. "We really only think it's about a six-year job to get back to the Moon, but it's a question of when you start," he says. "Okay, we can't start until the existing obligations have been worked off. . . so the budget money that we can foresee allows us to talk about envisioning a return to the Moon in, say, the 2018 timeframe."

Beyond that, the picture is less clear. Griffin sees using both pads at Kennedy Space Center, Fla., to launch shuttle-derived heavy-lifters in three pairs over six-week increments to get a notional 500-600 metric tons into LEO for assembly and departure on to Mars. While he says there has long been a consensus among exploration planners on that overall weight figure, the details remain to be worked out.

"We've not yet begun. . . but the first element of traceability to a Mars mission is the ability to get fairly large amounts of cargo up in a reasonable amount of time," he says.

Despite the uncertainty over ISS completion, Griffin says he expects NASA's station partners will also be partners in exploration beyond LEO, with the U.S. in the same leadership role it has taken on station development. He rejects editorial calls for an abrupt shuttle retirement in the wake of Discovery's problematic mission as "a classic, frankly, American, desire for instant gratification."

"The most important thing about retiring the shuttle is having an agreed-upon date that I can work to as an engineering manager to do the process," he says.