Back in May, the White House announced that it was convening a 10-member independent panel to take a long, hard look at NASA's plans for human spaceflight. The committee delivered a summary of its report (pdf) to the president's Office of Science and Technology Policy this week, solidifying many of the sober warnings that the panel had aired in a series of public meetings earlier this summer.

The nation's current program for human spaceflight appears to be "on an unsustainable trajectory," the report of the Review of U.S. Human Space Flight Plans Committee declares. "It is perpetuating the perilous practice of pursuing goals that do not match allocated resources."

As we noted in November, President Obama inherited a space program clouded with uncertainties, and the panel, led by former Lockheed Martin Chief Executive Norman Augustine, was asked to provide some clarifying guidance. That guidance takes the form of general assessments and pronouncements, along with five paths Obama could choose to pursue with NASA—two that assume a flat-lined agency budget and three that assume a roughly 15 percent boost over the next five years.

Among the issues dumped onto Obama's plate when he took office: the impending retirement of the space shuttle, an oft-delayed and much criticized replacement program for the shuttle known as Constellation, and whether to keep the International Space Station (ISS) afloat as it nears completion and the end of its assured funding.

The shuttle's final flight, currently scheduled for next September, will likely take place in 2011 given the time needed to prepare for launches with as many safety procedures as possible, according to the new report. Nevertheless, it will be several years after that before the U.S. has a means to get astronauts into orbit, and although the report provides one potential path in which the shuttle could be extended through that period, the committee found the interim reliance on international partners an acceptable alternative. Russian launchers and spacecraft already shuttle crewmembers, including Americans, to and from the ISS.

Constellation, the space launch hardware overhaul unveiled by the Bush Administration in 2004, is well behind schedule and won't be ready to send astronauts into orbit before 2017, the committee estimates. The Bush plan, which had Constellation astronauts returning to the moon by 2020, would not be executable until the 2030s, if ever, on NASA's current budget.

The space station, only now nearing the end of its lengthy construction, would be de-orbited in 2016 without a funding extension. The Augustine panel advises that the U.S. and its partners in the ISS would get a much better return on investment if the station were terminated in 2020 instead. "It seems unwise to de-orbit the station after 25 years of assembly and only five years of operational life," the report states. Without more money, keeping the ISS going would require scrapping the crew-lift rocket now under development for Constellation and relying on commercial operators instead. Exploration of the moon would be tabled for decades.

More money is the key to returning to the moon or achieving any of the more ambitious goals considered by the committee: sending humans on Mars flybys or setting up a rendezvous with a near-Earth asteroid or one of Mars's moons, for instance. With increases to reach a NASA budget of about $22 billion by 2014 (NASA's current outlay for fiscal year 2010 is roughly $19 billion), the report surmises, the space agency could continue Constellation toward a lunar landing in the mid-2020s, but the ISS would have to be junked in 2015.

And even with that increased budgetary profile, extending the life of the space station while simultaneously pursuing the moon or goals deeper in the solar system would necessitate scrapping at least some of Constellation's components and relying on the private sector to boost astronauts to low-Earth orbit.

Photo of a meeting of the Augustine committee in Cocoa Beach, Fla., in July: NASA