The US human spaceflight programme is on an "unsustainable trajectory", according to a report released yesterday by the Review of US Human Space Flight Plans Committee, otherwise known as the Augustine Commission. The report, commissioned by US President Barack Obama in May to review planned US human space flight activities, warns that the programme is "perpetuating the perilous practice of pursuing goals that do not match allocated resources."

Chaired by Norman Augustine, the retired CEO of technology giant Lockheed Martin, the report arrives as the US space shuttle programme is preparing for its final few missions. The US will then have to rely on Russian rocketry to launch its astronauts because it will be several years before the shuttle's successors – Ares rockets and Orion crew vehicles – are ready for flight.

More money needed

The committee's summary document, issued yesterday pending the completion of the full report, says that NASA's current budget cannot support human exploration beyond low-Earth orbit and that any programme to send astronauts further into space would require an extra $3bn annually beyond NASA's proposed budgets for the next five years. The Obama administration has requested $18,686m for the 2010 financial year, which starts on 1 October.

The committee offers five different options for future human spaceflight. The first, operating within the current budget, would keep humans in low-Earth orbit and provide funds to keep the space shuttle operating until 2011. The ISS would be brought down to Earth by 2016 and only after that would the first Ares launcher become available. Under this plan NASA could not afford to develop a lunar lander and lunar surface systems until "well into the 2030s, if ever". The second option, also operating within the current budget, would extend the ISS until 2020, and would start a programme of lunar exploration with the Ares V launcher.

The third option would follow NASA's current programme, but $3bn extra in annual funding would be needed to achieve the goals of de-orbiting the ISS, developing the Orion exploration vehicle and Ares launchers, and starting human exploration of the Moon. Appropriately funded, this option could see astronauts return to the Moon in the mid-2020s.

Destination for human exploration

The next option relies on an extra $3bn annually that would keep the Moon as the first destination for human exploration beyond low-Earth orbit. It would keep the ISS aloft until 2020, fund technology advancement, and use commercial launch vehicles to carry astronauts to low-Earth orbits. One version of this option would use the planned Ares V launcher for lunar exploration; another would extend the life of the space shuttle to 2015.

The final option, again relying on an annual budget of $3bn more than the current proposals, would start exploration in the early 2020s with lunar fly-bys, visits to LaGrange points and near-Earth objects, and Martian fly-bys. The option envisions a possible rendezvous with the Martian moons or astronauts' return to the Moon by the mid- to late-2020s. Launch options include the Ares V, a commercial heavy-lift vehicle and a new launcher based on shuttle technology.

Commercial launch services

The report emphasizes the potential contributions of international partners and commercial launch services for future manned space exploration. It points out that "Mars is the ultimate destination for human exploration, but it is not the best first destination."

President Obama commissioned the report as "an independent review of planned US human space flight activities with the goal of ensuring that the nation is on a vigorous and sustainable path to achieving its boldest aspirations in space."

The committee presented the summary report to presidential science advisor John Holdren and NASA administrator Charles Bolden. "We will release the final report when it is final," Bolden said, "but until the options it lays out are thoroughly considered, it would be premature for anyone at NASA to draw conclusions from the committee's work."