Forget all this talk about manned missions to Mars; is it time to scale back US space plans and land on an asteroid instead, Armageddon style?

Earlier this year, in response to a request from John Holdren, the White House's Director of the Office of Science and Technology Policy, NASA empaneled a committee and charged them with evaluating the future of US manned space flight. After a series of public meetings and the earlier release of an executive summary, its final report has been released.

The committee has concluded that NASA now has plans that don't reflect any sort of budgetary reality, and suggests that a "flexible path" series of missions to asteroids and orbital LaGrange points as realistic goals for the next few decades. Mars can wait.

Unsustainable



The committee is unsparing in its view of the US manned space program, from the first sentence onwards: "The US human spaceflight program appears to be on an unsustainable trajectory. It is perpetuating the perilous practice of pursuing goals that do not match allocated resources."

As that statement implies, the problems outlined by the committee are primarily financial. NASA has currently budgeted for the decade under a few assumptions—the retirement of the space shuttle at the end of next year and the de-orbiting of the International Space Station in 2016—that seem completely unrealistic.

The shuttle retirement date can only work if an aggressive mission schedule is kept through the remainder of this year and all of next. At this point, keeping that schedule would require launches to continue at double the rate NASA has achieved since it restarted launches after the Columbia disaster.

NASA has also failed to budget any money for the actual act of deorbiting the ISS, although that's probably not the worst of its problems. The ISS has only just reached its full habitation capacity, and further additions are still planned. That means we may end up with less than five years of it operating at planned capacity if deorbiting proceeds as scheduled. The committee, in a fit of understatement, calls this a poor return on investment, and says that NASA needs a renewed focus on getting as much as it can out of what it has built.

In sum, the committee expects that both the shuttle and ISS will continue to eat into NASA's budget for long after the current projections assume. Unfortunately, future planned flights will require the development of the Ares/Orion series of vehicles, and their program budgets assume that the money currently devoted to the shuttle and ISS will become available. The combination of that assumption being wrong with NASA's need to plan for a flat budget more or less means that we're not going anywhere.

"The heavy-lift vehicle, Ares V, is not available until the late 2020s, and there are insufficient funds to develop the lunar lander and lunar surface systems until well into the 2030s, if ever," one section of the report concludes.

At best, an accelerated development schedule for the manned launch vehicle would see a seven-year gap between the retirement of the shuttle and the availability of a crewed replacement. Given the increasingly international nature of space exploration, the committee found that acceptable, but felt that the US should seriously consider alternatives for putting humans into space, given that the service date for Ares I (the intended replacement) was likely to slip. Their favored solution was a series of guaranteed contracts that would foster the development of a commercial alternative.

Any manned mission beyond Earth orbit, however, will require a heavy lift capability. The committee considered a variety of options, including updating existing launch vehicles, creating an unmanned derivative of the shuttle, and the further development of the planned Ares V heavy lift vehicle. Each of these was considered to have its strong points, but the language of the report makes it pretty clear that the committee would like to see a simplified version of the Ares V dubbed "Ares Light."

This would sacrifice about 10 tons of lift capacity (still leaving it with a hefty 140 metric tons), but enable it to carry both cargo and crew. Combined with shifting smaller manned launch vehicles to the commercial sector, this would allow NASA to develop only a single new launch vehicle, which would have major budgetary and safety benefits.

This leaner approach—developing fewer vehicles and avoiding goals around hardware that may not materialize—extends to the advice on future missions. Developing a crewed vehicle that can return astronauts from surfaces like that of the Moon or Mars is simply a challenge that NASA doesn't have the money for. As such, the report argues that we should be concentrating on a series of extended missions outside of Earth orbit that don't necessarily involve human landings.

So, for example, a rendezvous with a near-Earth asteroid could provide a wealth of scientific data and practical experience with extended spaceflight without adding the challenge of a significant gravity field to overcome. The report also suggests that human trips to stable orbital locations called LaGrange points are also in order. We're already placing astronomical observatories there, and the combination of heavy launch capabilities and manned intervention could make for equipment that rivals the Hubble in terms of continued scientific returns.

To Mars! (eventually)

This doesn't mean giving up on Mars; rather, "the Committee finds that Mars is the ultimate destination for human exploration of the inner solar system, but it is not the best first destination." Extended missions to the planet could involve landings on its moons or in-orbit control of rovers that have sample return capacity.

The report itself lays out a large variety of options, from vehicles to missions, but it's clear where the preferences of its authors lie. But even if the plans they outline are far more realistic than those that have been floated around NASA, there will still be serious challenges. Even more conservative vehicle development plans will require a boost of $3 billion to NASA's 2010 budget, and adjustments for inflation from then on. And development of the Ares vehicles has already begun—there's a test flight being prepped for launch at the moment—and may be difficult to change.

If nothing else, however, the report rightly focuses on the fact that NASA has been given a series of tasks it cannot possibly achieve, and it can only approach success by turning its back on the ISS, the structure it has spent the last several decades planning and building.