The electric solar sail, or ESAIL, is a ‘sail’ that provides propulsion for a spacecraft simply by using the solar wind, no fuel whatsoever. Invented only very recently, in 2006, a prototype has not yet been created. But now one of the primary limitations have been overcome, the production of the 1-km-long ESAIL tether, something which had been considered impossible by most global experts in ultrasonic welding.
The technology, which works by creating a electric field that deflects solar wind protons and takes momentum from them, offers the future possibility of fast, cheap, and fuel-less travel throughout the solar system. And perhaps more interestingly, an economically viable way to extract resources from asteroids.
Four years ago, it was the view of international experts in ultrasonic welding that it would be impossible to produce tethers made of extremely thin wires welded together every centimeter. (It’s necessary for the tethers to be created this way, though, so that micrometeoroids, like those that cause meteor showers, don’t cause debilitating damage to the structure.)
But now, researchers at the University of Helsinki have succeeded in creating a 1-km-long ESAIL tether, featuring 90,000 ultrasonic welds. This provides proof that it is possible to manufacture full-size ESAIL tethers. And thanks to this breakthrough, “the theoretically predicted electric sail force will be measured in space during 2013,” the University of Helsinki notes in a news release. The Estonian ESTCube-1 satellite launching in March will first test out a 15-meter-long tether. Followed by a test of a 100-meter tether in 2014.
The development of such a technology would allow for extremely cheap, large-scale gathering of the abundant resources available in space, primarily those available in asteroids and comets.
In fact, all of the “gold, cobalt, iron, manganese, molybdenum, nickel, osmium, palladium, platinum, rhenium, rhodium, ruthenium, and tungsten” that we mine from the Earth’s crust was deposited by asteroid impacts well after the crust on the planet cooled. It’s been estimated that these and many more elements that are used by modern civilization in large quantities may run out within 50-60 years.
The ESAIL also would allow the large-scale mining of water, oxygen, hydrogen, and construction metals; to be used in space. This would completely bypass the currently extremely expensive process of sending objects into space — simply build it there first if it’s possible to do so.
Image Credits: Timo Rauhala; Henri Seppänen & Sergiy Kiprich; Eros via Wikimedia Commons