Lawmakers have tapped the brakes on NASA's post-shuttle future. When the House appropriations subcommittee handed back President Obama's proposed $18.7 billion NASA budget last week, the bill was $483 million lighter.

Most notable among the cuts was a 16 percent slash to the agency's budget for manned space exploration, originally weighing in at $4 billion.

The move "reflects the uncertainty surrounding NASA's current strategy for replacing the space shuttle and returning astronauts to the moon by 2020," wrote Space.com.

Rep. Alan Mollohan (D) of West Virginia, chairman of the subcommittee, stressed that the cuts did not mean Congress has lost faith in NASA. Instead, the congressmen are waiting for the results of a 10-member panel that's looking into the future of manned mission.

With NASA's shuttle program coming to an end in 2010, the White House formed a commission, headed by former Lockheed Martin chief Norm Augustine, to investigate the Orion capsule, Ares I rocket, and the other technologies on the table. Their report should come in August.

The budget cut is "a deferral taken without prejudice; it is a pause, a time-out, to allow the president to establish his vision for human space exploration and to commit to realistic future funding levels to realize this vision," Mollohan said during the June 4 subcommittee meeting.

Mr. Augustine has already said that his panel is not bound to the current plan, known as Constellation.

"We will be looking at different architectures, as well as the existing architecture, and I am not in a position to make any predictions," he said during a briefing in May. "We have been asked to provide options."

As Peter N. Spotts, the Monitor's science correspondent, wrote last month:

One important political factor that could keep Constellation on track: Without it, US astronauts would have to rely on Russian Soyuz launches to reach the International Space Station far longer than they would otherwise would. An approach other than Constellation would take years to develop. It is a potential gap in US capabilities that former NASA administrator Michael Griffin called "unseemly."