NASA's plan is to build a pair of new rockets called Ares (one for crew and another heavy-lifter for cargo) and a capsule called Orion. The goal is to fly Orion to the station by 2015, land a crew on the moon by 2020, build a moon base and eventually get to Mars.
"NASA has a plan," shuttle program manager John Shannon told the Augustine panel. "I think it was a well thought-out plan ... but it has not been funded to the level that we would need to see it through."
NASA, commercial companies and other groups outlined other options for traveling to the space station and the moon. During a series of meetings in July, the panel is expected to consider why the United States should go.
"If the objective is Mars, then you definitely want a heavy-lift rocket," Zubrin told Discovery News. "If you're not going beyond low-Earth orbit, there's no need for it."
Zubrin, who is hoping to testify before the commission, is concerned that if the country's focus and resources are pinned to lunar exploration, the ultimate goal of getting to Mars will be lost.