Mining the Moon’s hidden resources
The Moon is almost as large as North and South America combined, with only the tiniest sliver explored by Apollo astronauts or Soviet robots. Astrobotic is developing the machines that will prospect and recover resources that both enable affordable exploration and raise living standards on Earth.
Ice at the poles
None of the Apollo and Soviet missions landed at the Moon’s poles, where vast amounts of frozen water, methane, ammonia and other compounds have been sensed from orbit. If confirmed by Astrobotic prospecting robots, these resources can be turned into life support for human outposts, and into propellant to refuel spaceships for their return to Earth. Living off the land using these volatiles will dramatically lower the cost of space exploration and lead to permanent settlements off planet.
Astrobotic rovers are solar powered, and the ice deposits they can access are expected to be covered by a few inches of dry soil, based on orbital readings. Scraping off this layer and then scooping up the ice requires an excavator that can work in the one-sixth lunar gravity. With reduced gravity, machines have less traction to overcome digging resistance.
The most recent bucket-wheel prototype for the excavating rover
Astrobotic solves this problem by concentrating the digging into a small area so that even in light gravity, the excavator has enough traction to force the soil to move. A wheel with a dozen buckets on its edge does the scraping and scooping, taking repeated small bites. This is compared to a dozer approach that forces a broad blade into the soil, generating a lot of pushback. Traction is increased by mounting the bucket wheel transverse to the wheels, so that any pushback would need to force the wheels sideways.
Astrobotic has won two NASA contracts for the development of an excavator prototype for the Moon. The device is expected to be completed by early 2013.
Energy and metal resources
Astrobotic also will develop mining machines to recover energy and metal resources.
Over billions of years, the solar wind has deposited a surface layer of volatiles into the lunar soil. One of the elements is helium3, a nonradioactive element with two protons and one neutron. When two helium 3 atoms are fused, the power released can be harvested directly as an electrical current. Today’s nuclear fission plants, besides using radioactive fuel, are inefficient because they first generate heat which then powers steam boilers, which then must spin turbines to create electricity. Fusion plants using helium 3 for direct electricity production will be compact, efficient, and generate almost no radioactive waste.
A single shipment of helium 3 back to Earth – small enough to fit into a single tanker truck – could generate sufficient electrical power to sustain the needs of the United States for a year. Fusion reactors to use helium 3 have not been developed, in part because technologists are waiting for robot prospectors to confirm that helium 3 can be recovered in sufficient quantities from the lunar soil. Astrobotic will develop and deliver those prospecting machines.
Millions of asteroids have crashed into the Moon. About six percent of all asteroids are metal rich, primarily iron and nickel, so likely six percent of the Moon’s craters were created by nickel-iron impacts. The great unknown now is whether a sufficient percent of these impacts took place at low speeds to preserve a metal mass in the crater’s center. If they did, then they could be mined to supply lunar colonists with natural stainless steel, and Earth with the rare platinum-group metals that would be worthwhile to ship back to the home planet. Platinum is in great demand for pollution control devices, such as catalytic converters for auto exhaust systems.
