WASHINGTON—Scientists are rushing to put together a scientific case for sending robots and astronauts back to the moon in the coming decade.
Experts say Earth's nearest neighbor contains a unique record of the infancy of the solar system, including our own planet, and may shine light on how and when life began. But some are skeptical that returning to the moon is worth the cost and the risk. After all, we've been there, done that.
A generation ago, the world marveled at the six American Apollo landings and three Russian Luna round trips to the moon. Then interest faded, and to this day, researchers haven't finished studying the 850 pounds of rocks they brought back in the 1970s.
President Bush made a renewed lunar project a key part of the "Vision for Space Exploration" program he unveiled in January 2004. He portrayed the moon as a steppingstone for human exploration of Mars and eventually other worlds.
"Our road to Mars goes through the moon," NASA Administrator Mike Griffin says repeatedly.
Space exploration, not science, is the primary reason for returning to the moon, Griffin says. But he thinks a strong research program is important to win scientists' support for the president's expensive vision.
The space community is painfully aware of the disappointing performance of the International Space Station, now circling the Earth with little scientific value to show for its $100-plus billion cost. They want to be sure that a new round of lunar expeditions produces good science as well as good engineering.
"The kind of criticism we're receiving in connection with the ISS needs to be headed off at the pass for the moon," Griffin told NASA executives.
"We don't want the science community to be hostile to the lunar program," said Paul Hertz, chief scientist at NASA's Science Mission Directorate. "Weak science would be questioned and could jeopardize the entire lunar program."
As a result, NASA has asked lunar experts outside the space agency to propose a detailed science program for the moon.
In response, the National Academy of Sciences created a Committee on the Scientific Context for the Exploration of the Moon, which will present its recommendations this summer. The committee, which is headed by George Paulikas, retired vice president of The Aerospace Corp. of El Segundo, Calif., met for the first time last week in Washington.
The moon is "a unique vantage point for understanding the evolution of the Earth-moon system and for the scientific exploration of the solar system," Charles "Chip" Shearer, an expert on meteors at the University of New Mexico, Albuquerque, told the committee.
Norman Sleep, a geophysicist at Stanford University, in Palo Alto, Calif., called the moon "a tape recorder" that preserves the history of the solar system. "The moon is much better than Earth at retaining the record of the past," he said.
Scientists think the moon was created when a Mars-size object—nicknamed Theia—smashed into the Earth about 4.5 billion years ago. The collision hurled a huge gob of molten rock into space that solidified and became our permanent satellite.
About 600 million years later, Earth, Mars and the moon were bombarded by a violent storm of giant rocks, hundreds of miles across, left over from the formation of the solar system. The scars of that barrage are still visible on the face of the moon, but were mostly covered up and lost on Earth.
Some scientists say pinning down the time of the bombardment will help them figure out when life began on Earth. Sleep speculated that heat-loving microbes may have arisen shortly after Earth was born and survived the rain of rocks by hiding deep within the planet's crust.
Astronauts who visited the moon three decades ago were able to explore only a tiny portion of the surface facing Earth. The far side, the polar regions and the interior remain mysteries.
NASA's return to the moon will begin with the launch of an unmanned Lunar Reconnaissance Orbiter in October 2008 to identify the best places and resources for future landings.
The first robotic lander is planned for 2010 to a site yet to be determined. A second lander will aim for the 1,300-mile-wide Aitken Basin at the moon's south pole. The basin is the largest and oldest impact crater in the solar system, and it may hold a large store of frozen water for astronauts to use.
The Aitken basin is "one of the richest scientific targets on the moon," said Bradley Jolliff, a geologist at Washington University in St. Louis. "We can learn key aspects of solar-system science—what happened in the first 500 million years—where the record on Earth is almost gone."
The first manned landing won't take place until at least 2018, almost 50 years after Neil Armstrong and Buzz Aldrin set foot on the moon. New, larger lunar landers will carry crews of four and packages of scientific instruments for stays of four to seven days.
After 2024, NASA hopes to establish a semi-permanent outpost, which will shelter astronauts for stays of 30 to 90 days, perhaps even six months. The astronauts will be able to make scientific observations near their base, and will be aided by robots that can travel hundreds of miles beyond.
"Science is an important part of the president's vision even though it isn't the key driver," said Jeffrey Taylor, a member of NASA's Lunar Exploration Analysis Group from the University of Hawaii in Honolulu. "We can do them both at once. No one has to get the short end of the stick."
For more information online, go to www.lpi.usra.edu/leag/reports.html
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(c) 2006, McClatchy-Tribune Information Services.
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