Though humans will not return to the moon for at least another 13 years, researchers are already thinking about technologies for what many of them see as a logical next step: a permanent presence there.
On Wednesday, NASA announced a prize competition for inventors and scientists, to design an automated robot able to scoop and carry moon soil. These competitions help by “reaching out to the research communities you could not reach otherwise,” said Brant Sponberg, the manager of NASA’s Centennial Challenges program.
Other challenges include building a better astronaut glove-as the current model strains the user’s hands-and figuring out how to transmit power through a light or laser beam. A breakthrough there would mean robots could leave their bulky power source behind.
The new challenge, with a $250,000 prize purse, involves the mining of the moon’s regolith, the fine rock rubble formed by tiny meteorites striking the lunar surface. NASA is challenging inventors to build an autonomous excavator, no heavier than 25 kilograms, that can move at least 150 kilograms of regolith from place to place in 30 minutes.
But regolith is tough to work with. Its grains are jagged and glassy, and tend to get attached to things; static charge builds up on them, so they stick to surfaces such as space suits and equipment like iron fillings to a bar magnet.
Barring that, though, it turns out a device as simple as a microwave oven could turn the stuff to pay dirt. Dr. Lawrence Taylor, a geoscientist at the University of Tennessee, has used microwaves to scorch moon soil. He described his results in a recent paper in the Journal of Aerospace Science. The microwaves cause the iron in the regolith to melt and then resolidify, producing a glassy material, blocks of which could be used as a building material. They might also free hydrogen and oxygen trapped in the minerals. The only drawback is a scarcity of moon soil on Earth to experiment on.
Nonetheless, Taylor posits that lunar soil is the most suitable material for immediate use there. He envisions a road-paving wagon traversing the lunar surface, using microwaves to melt the top layer of soil. This could yield a trafficable road surface for lunar vehicles.
Meanwhile, Lockheed Martin and NASA are working on a way to extract and store oxygen from the moon’s surface. They plan to use microwaves or lasers to melt metal oxides in the regolith, which are made of metallic atoms bonded with oxygen-on Earth you would call it rust. The process eventually produces water, which is then split apart with electricity into hydrogen and oxygen gas.
The goal is to produce oxygen gas and then liquefy it, storing it in large cylinders on the moon surface. These could provide breathable air to a would-be moon base, or gas up Earth-bound spacecraft. In turn, the spacecraft could carry more cargo, since about four-fifths of the weight of a typical mission to the moon is taken up by fuel.
A lot of this technology is still science fiction though, since the distribution of useful resources on the moon, such as frozen water and metals, remains unknown. But the armada of satellites headed toward the moon will soon start prospecting it. Still, the fact that researchers are thinking about them shows their hope that when humans return to the Moon, it will be to stay.
