KAILUA, KONA, Hawai'i — The next generation of astronauts may soon be able to manufacture their own oxygen and water supplies, turning lunar rocks and soil literally into thin air.

A slew of scientists, engineers and researchers began field tests this year on a NASA system to drill for metal-rich soil, chemically extract the hydrogen and oxygen components, and form water and oxygen.

The idea is to make astronauts self-sufficient over an extended period of time at an outpost on the moon and minimize the amount of water and oxygen that must be transported from Earth.

On a seven-acre patch of volcanic, iron-infused soil at the 9,600-foot level of Mauna Kea volcano on the Big Island, scores of scientists and researchers have spent the last two weeks running three machines through their paces.

"We met all of our major objectives," Tom Simon, NASA's In Situ Utilization Project chief engineer, said today. "We had everything running full on and we were producing oxygen at outpost levels."

NASA hopes to generate 1 to 2 metric tons of oxygen annually, enough to sustain four to six people living at a lunar outpost.

"There's a lot more science to do, but we need to be able to live on the surface of the moon for 500 days to test for Mars," said Bill Larson, Kennedy Space Center mission director. "We've got to get it all working and reliable when we get to Mars."

The ability to churn out air, water and even rocket fuel will make a huge dent in cost, Larson said.

"We've always carried everything we need on our back," he said. "We have to learn to live off the land, much like Lewis and Clark."

For example, Larson said, if it costs $50,000 per pound to send supplies into orbit and this technology can kick out 2,220 pounds of oxygen a year, it conceivably could save $10 billion in launch costs.

The system includes three machines: a prospecting dune buggy robot called Scarab equipped with a drill to sample soil, and two complementary production machines that can syphon off the oxygen and hydrogen elements.

Within the last year, tests have been conducted on the dry, loose sands of Moses Lake, Wash., and under pressurization conditions at a facility in Arizona.

"The field testing is to deal with all the issues and problems that could come up. We've thought about all kinds of questions - terrain, temperature, dark," said Dave Wettergreen, a Carnegie Mellon University research scientist who worked on Scarab. "The challenge is integrating all the engineering and you have to all that before you're ready for the moon."

The Mauna Kea site was chosen for its lunar-like soil chemistry, said Frank Schowengerdt, director of the University of Hawaii-Hilo's Pacific International Space Center for Exploration Systems, or PISCES.

"The Big Island may be the closest you can come on Earth to being on the moon," he said. "Much of the island is covered with ash and rocks that are very similar to what you would find on the moon."

The scientists and researchers are looking beyond the tests, beyond the moon and beyond 2020.

"In my lifetime, I'd like to see astronauts going to Mars and growing plants there," Simon said. "It's very doable."