Technology developed to prolong the lives of robotic probes on the moon and Mars is being tested for a new use on Earth: keeping solar panels dust-free.
A mere one-seventh of an ounce of dust spread out over a square yard of solar paneling can cut the amount of power harvested by 40 percent, according to researcher Malay Mazumder, with Boston University. More than four times that amount of dust settles on Arizona every month. The Middle East, Australia and India are even dustier.
Mazumder and colleagues have spent nearly a decade developing a transparent, electrode-laced shield that can zap away dust from the surface of a solar panel. Embedded sensors detect when dust levels reach a critical mass and automatically trigger an electric charge that cascades across the shield, levitating and transporting dust grains that have settled on the surface.
Tests show it takes about two minutes to clear off 90 percent of the dust, said Mazumder.
NASA picked up on the dust-busting technology as a way to keep solar panels on its landers and rovers operating more efficiently on the dusty surfaces of the moon and Mars. The agency also is looking at using the shields to keep dust from settling on heat radiators, communications antennas and even the spacesuits worn by future astronauts.
A demonstration is scheduled for next month in Arizona as part of a two-week NASA field research program known as the Desert Research and Technology Studies, or Desert RATS.
Electrically-sensitive shields on a prototype lunar habitat will be tested to see if they can remove dust prior to the docking of a prototype rover, said Carlos Calle, who heads the Electrostatics and Materials Physics Lab at NASA's Kennedy Space Center in Florida.
Mazumder and colleagues see a much wider use for the technology, including harvesting more of the sun's energy for power on Earth. Currently, solar panels are generating only about .04 percent of the world's total energy production, Mazumder told Discovery News.
If just 4 percent of Earth's deserts were put to work harvesting solar power, the entire world's annual demand for energy -- roughly 15 trillion watts of power -- could be met, he added.
"Most of the places where it is sunniest also happen to be the dustiest," Mazumder said. "It is very difficult to go in that weather to clean the panels so I think it should be automatic, robust and operated in such a way that is utilizes the energy really efficiently.
"What we're trying to do is define the technology that will make is the most inexpensive so that the cost of production doesn't increase by more than 2 percent," he added.
That would add about $10 for a self-cleaning shield onto a panel costing $500.
There are some limitations to the technology, points out Alex Biris, with the University of Arkansas in Little Rock.
"The electrodes need to be transparent and flexible so they don't obscure the solar cells," Biris told Discovery News.
Colleague Doug Wilson, who is working on the system's electronics and power supply, sees solar-powered cell phone towers as another potential market.
"They're in more remote locations, and they need to be serviced regularly. Having something that would clean itself would be big plus for them," Wilson said.
Mazumder presented his research this week at the American Chemical Society annual meeting in Boston.