Turning Lunar Dust into Gold
On Hawai`i’s Mauna Kea volcano, which rises over 13,000 feet above sea level, there is a mid-level base facility where scientists can pretend they are on the Moon. Hawai`i’s volcanic terrain, soil and remote environment provide an ideal environment for testing instruments and equipment that someday may be used by astronauts at a lunar base.
Recently, a team of scientists working for the Pacific International Space Center for Exploration Systems (PISCES) demonstrated its first field test for NASA’s In Situ Resource Utilization (ISRU) Project. Research Operations Manager John Hamilton supported the mission simulation to show how astronauts will be able to prospect for resources on the Moon to make their own oxygen, fuel and water from lunar rocks and soil. A key motivation of these experiments is the fact that almost half the moon, by weight, is made of oxygen.
Representatives from four NASA space centers (Johnson, Kennedy, Jet Propulsion Laboratory and Glenn Research Center) were at the test site. Engineers from the Canadian and German space agencies also were at the site, as were representatives from Carnegie Mellon University, Lockheed Martin, and Michelin North America – making this field test a true global effort.
The crew convened at a small campsite located at the bottom of a rough and narrow four-wheel-drive road. For some, this field test was their first chance to meet and work with their colleagues outside of a lab. Much of the equipment had been developed by teams working in different locations. During the two week field test, the crew worked through complications that arose as the different pieces of hardware were brought together for the first time.
Strong winds had been gusting for days, reaching up to 45 mph. Most of the crew were bundled in protective clothing, with eye protection, dust masks, large hats, ear plugs and gloves. Any area left exposed would be covered in a layer of gritty dust, as was the large platter of papayas, pineapple and other exotic fruit the scientists had brought in from Hilo. Although wind will never be an issue on the Moon, the dust added an unexpected level of realism to the operation.
"We know we have to do deal with lunar dust," said Jerry Sanders, ISRU Project Manager at NASA’s Johnson Space Flight Center. "We just didn’t know we had to deal with it right now!"
The type of dust that attracted the engineers to Hawai`i is called "tephra," a fine, powder-like material that is ejected during a volcanic eruption. Tephra works well in the prototype chemical processing units because it mimics the dust found on the Moon.
A NASA-developed rover called SCARAB showed how a prospecting rover could dig beneath the dusty lunar surface to process soil in order to extract oxygen. A similar rover on the Moon could look for water ice and volatile gases such as hydrogen, helium and nitrogen in the permanently shadowed craters of the Moon’s poles.
Larger systems could produce oxygen from greater quantities of Moon soil. Roxygen (developed by NASA) and the Precursor In Situ Resource Utilization Lunar Oxygen Testbed, or PILOT (developed by Lockheed Martin) both feature a hydrogen reduction system that can produce and store oxygen from soil.
"We’re trying to make the lunar outposts more self-sustaining," explained Tom Simon, head of the OPTIMA program at NASA’s Johnson Space Flight Center, which is overseeing the development of the PILOT and ROxygen test units. "We want to produce oxygen, but we also want to extract oxygen from the regolith so that we can combine it with what’s left of the residual hydrogen from the descent tanks and make water. Our goal is to never send a tank of oxygen or a tank of water to the Moon."
During this field test, a robotic excavator, similar in size and weight to those currently exploring the planet Mars, showed how soil could be extracted and delivered to the ROxygen system. Also tested was an excavator that uses a bucket drum to collect and deliver soil to the PILOT system.
"It’s one thing to test these instruments in the laboratory,” said Hamilton, “but that really doesn’t tell you how it will perform during a lunar mission. Our challenge is to replicate those conditions as closely as possible to ensure that the test results will be a true reflection of how these instruments will perform on the Moon."
Advanced Life Support
NASA’s lunar exploration plan says that on-site lunar resources could generate about one to two metric tons of oxygen per year, enough to support four to six people annually. Since it takes about 100 kilograms (kg) of soil to get 1 kg of oxygen, team leaders are looking at electrostatic and magnetic separation techniques to possibly concentrate the soil and increase the production rate. Next June, for example, testing will begin on a process that could potentially draw as much as 10 or 20 kg of oxygen out of every 100 kg of soil.
Other concepts tested at the PISCES test site included a new lunar wheel developed by Michelin North America, a sample coring drill developed by the Northern Center for Advanced Technology in Canada, and a night vision camera developed by Neptec for navigation and drill site selection. The wheel has plastic spokes that can absorb shocks, prevent flats and give better traction. The coring drill is a small unit that can autonomously dig beneath the surface without any “down-the-hole” electric components.
“We hope to make sure that we are not missing any process steps,” said Simon. “We are just getting a handle on where our starting point is based on the precursors. This equipment will get smaller and more compact each and every year.”
The Canadian Space Agency is also contributing a utility support vehicle for personnel and hardware transportation, and the German Space Agency is developing an autonomous mole drill, which can burrow deep beneath the surface to search for water or other resources.
Frank Schowengerdt, director of PISCES, explains that the Center uses state funding and working agreements from public and private partners, including several universities, to involve students from around the world in space research. “In the next two years, PISCES will conduct research and testing on the Big Island, and we will be major contributors to the space exploration programs of several countries planning missions to the Moon, including the United States.”