Traveling light -- between planets

Wringing water out of the Martian atmosphere to make rocket propellant for a return voyage to Earth may sound like the stuff of a Grimm Brothers fairy tale.

However, like the dwarf who helped the miller's daughter become queen by spinning straw into gold, scientists are conducting research that someday may make space-refueling stations, and the possibility of interplanetary travel, a reality for all of us.

Using a technology known as in situ resource utilization, or ISRU, researchers are studying ways to mine natural resources on other planets. Their efforts could greatly reduce the cost to visit, and eventually live in, space. Current projects include efforts to produce rocket propellants from water in the air, and to mine aluminum for a special antenna that could collect solar energy and convert it into electricity for manufacturing on another planet.

ISRU technology has been around for several decades, but in recent years it got a boost from the Mars and other longterm missions.

"ISRU technology is available now, and it could be used to develop space in a big way, to the point where people could live in space independently," says Peter Curreri, group leader of the biological and physical space research laboratory at NASA's Marshall Space Flight Center in Huntsville, Ala.

Martian refueling stations could greatly decrease the payload weight, and thus the cost, of long-distance, manned space travel. About 10 percent of the Space Shuttle's weight is payload and fuel. It now costs at least $10,000 per pound to put a spacecraft into low-Earth orbit, according to the National Aeronautics and Space Administration. That's more than double the price of gold. Not carrying extra fuel also leaves more room for passengers and scientific experiments.

"It's the same as an airplane from Boston to Seattle being able to refuel in Seattle, rather than taking all the fuel for a two-way trip. If the plane is full of fuel, there's less room for passengers," says Adam Bruckner, professor and chairman of the astrobiology program at the University of Washington in Seattle.

Dr. Bruckner and his colleagues are experimenting on Earth with a material called zeolite 3A that could be an absorbent of water in the Martian atmosphere. Other types of zeolite are used on Earth to take impurities out of chemical flows or to dry up spills.

On Mars, the aim is to build a system in which ambient winds and fans would blow Martian atmosphere over a bed of zeolite 3A. Once the zeolite 3A is completely saturated with Martian water, it would be put into a sealed chamber and heated with microwave radiation to separate and collect the water. The zeolite 3A then could be reused.

The extracted water could be used for life support, or to create rocket propellant by separating the hydrogen from the water, and combining it with carbon dioxide to get methane and oxygen, which makes a potent fuel.

It could take as long as a year to accumulate enough water, but the cost savings over transporting fuel could be significant, Bruckner says. He adds that the water-extraction system could be set up and run remotely with robots. The technology isn't likely to be used on Mars for at least another decade.

Mr. Curreri of the Marshall Space Flight Center is looking at ways to get energy to planet surfaces. He and his colleagues want to mine aluminum to make a "rectenna," a receiver that can generate electricity from solar energy, beamed in the form of radio waves to the surface of Mars from a mother ship orbiting above. The energy collected would be stored in a power grid.

"This could power manufacturing on Mars," says Curreri, who will present a paper on his project at the upcoming October meeting of the International Astronautical Federation in France. Again, this technology is in the early research stage.

Page: 1 | 2