Should we stay, or should we not bother? A moon base could be a waste of resources, say critics.NASA

Sending astronauts to the moon could be a dead-end journey if the real goal is to get to Mars, says a space exploration advocate who plans to take advantage of an ongoing review of the U.S. space program to lobby for a new destination.

"The fundamental question is 'Do you have a space program that's going somewhere or not? Do we want to go to Mars in our lifetime?," said Robert Zubrin, an engineer, author and long-time proponent of Mars exploration and settlements.

Zubrin's latest target is the presidential commission tasked to review the U.S. human spaceflight program. The panel, headed by former Lockheed Martin chief executive Norm Augustine, held its first public meeting last week.

President Barack Obama inherited a space program big on plans and short of money. Under the Vision for Space Exploration laid out by the previous administration, NASA was to complete construction of the International Space Station, retire the expensive and risky space shuttle fleet and develop a new space transportation system that could not only ferry crews to the station, which orbits about 225 miles above the planet, but double as deep-space vessels that can travel to the moon and beyond.

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.

"Mars is where the challenge, the science and the future is," he said. "We don't want to spend the next 20 years solving the wrong problems."

The commission's report is expected in August.