An international team of astronauts will be living and working at a permanent moon base to be built at one of the resource-rich lunar poles within two decades, NASA announced Monday.

Earth’s first off-world colonists will cruise the surface in a new generation lunar lander that will function like a low-gravity pickup truck, possibly journeying to the dark side to build the most ambitious collection of observatories ever constructed, NASA said.

The announcement of NASA’s vision to build a permanent scientific research station on the moon represents the space agency’s first outline of its plans once it reaches the moon, scheduled no later than 2020.

“We will begin with short missions. Then we will build up to the point where we are staying 180 days, and then we will have a permanent presence,” Doug Cooke, deputy associate administrator for exploration systems, said at a news conference at Johnson Space Center in Houston.

The permanent base could be operational as early as 2024, officials said.

In 2004, President Bush announced the Vision for Space Exploration, which proposed a return to the moon by 2020, as the first step to an eventual manned mission to Mars. Since then, NASA has embarked on a $100 billion-plus program to design a new launch system and crew vehicle capable of carrying four astronauts to the lunar surface. To free up money to carry out the vision, NASA will mothball the space shuttle by 2010.

But until now, it was unclear what NASA had in mind for the moon. Was it to be nothing but a rest stop on the highway to Mars? Or was it to be a permanent off-world home for human beings, much like the International Space Station?

“We’re going to go after a lunar base,” said Scott Horowitz, associate administrator for exploration systems. “This is a very, very big decision; one of the few where the science and exploration communities agree.”

Space science advocates have been complaining in recent months that money for basic scientific research is being raided to pay for manned spaceflight, which they feel is an expensive proposition, the benefits of which are unclear at a time when robotic explorers can perform many tasks far more cheaply.

In choosing to locate the moon base at either the north or south pole, NASA was persuaded by three factors. One, the sites are relatively unexplored. Two, temperatures are more moderate there than in the searing heat of the equatorial bright side and the numbing cold of the dark side. Lastly, previous NASA moon missions detected the presence of unusual amounts of hydrogen at both poles.

This undated artist's rendering released by NASA shows an artist's concept of a new lunar lander. Unveiling the agency's bold plan for a return to the moon, NASA said Monday it will establish an international base camp on one of the moon's poles, permanently staffing it by 2024, four years after astronauts land there.

Some scientists have speculated this could be traced to hidden ice deposits, a potential source of water for moon colonists.

Lunar experts are particularly interested in an area in Shackleton Crater at the south lunar pole.

NASA officials said they won’t make a final decision about where to build the lunar base until they obtain results from the Lunar Reconnaissance Orbiter, a mapping mission scheduled for launch in 2008.

Deputy NASA administrator Shana Dale said space agencies from Australia, Canada, China, Europe, Japan, India and Russia have expressed interest in participating in the U.S. lunar program.

Timeline

In 2004, the year after the space shuttle Columbia accident that killed seven astronauts, President Bush announced a plan to return astronauts to the moon by 2020, and a later mission to Mars. The 16-year-long venture to the moon will take twice as long as NASA’s first trip there took in planning.

The estimated time frame for NASA’s lunar plans are:

¢ 2009 – a first test of one of the lunar spaceships.

¢ 2014 – the first manned test flight of the Orion crew exploration vehicle, but no moon landing.

¢ 2020 – the first flight of the four-astronaut crew to the moon.

For four years, the lunar base won’t be built up enough for long visits, so astronauts will only spend a week at a time. But after that, NASA envisions people living on the moon for six-month stints.