It's time to talk trash! Space trash, to be specific. Trash collection has never really seemed like an enviable job to most of us. But, what if you were collecting trash from outer space? That sounds like what could be the coolest job in the galaxy.
Tethers Unlimited, (TUI) a 15-employee company based in Bothell, Washington, aims to begin cleaning up space junk later this year by launching their "Terminator Tether" into space aboard AeroCube-5 satellites. Once the tether attaches itself to an object - an obsolete satellite, for example, it then unfurls a long fiber or wire. The tether collects electrons as it drags through the Earth's magnetic field at orbital speed, creating a voltage called "Motional EMF." The resulting drag from the electrons collected on the tether can then deorbit the satellite, causing it to fall back to earth. According to TUI's website:
"This module uses active electron emission technologies to greatly increase the electrodynamic forces, enabling it to deorbit most LEO spacecraft with in a period of several months. The Terminator Tether modules will typically mass less than 2% of the host spacecraft's dry mass."
Rob Hoyt, a physicist and inventor, came up with the idea seventeen years ago, while working out of his house. There are currently over 21,000 pieces of space junk larger than a grapefruit circling the Earth, threatening any manned or unmanned spacecraft up there. Hoyt proposes that TUI's method of satellite removal would be a fraction of the cost of using rocket fuel to deorbit the object.
In 2007, the United Nations Committee on Peaceful Uses of Outer Space adopted a set of space debris mitigation guidelines, which included a 25-year deorbit requirement for satellites in Low Earth Orbit (LEO). Hence the need for Hoyt's company.
Tethers Unlimited is well on their way to astronomic success, if their concepts prove viable. Hoyt expressed his optimism by telling the Puget Sound Business Journal:
"There's a lot of cool stuff going on here in the state, and we're rebuilding the space industry here. We're getting more of the new space companies and organizations taking hold here. We could still use better support from the state."
Tethers Unlimited is also working to develop a rocket engine that uses solar energy to split water into hydrogen and oxygen, which it would then use as fuel. That's right - a rocket that runs on water.
Another very impressive technology from TUI is what they call a "Trusselator" device. It's a technology that uses additive manufacturing techniques (similar to 3D printing) to enable on-orbit fabrication of high-performance carbon-fiber truss structures. Per TUI's website:
"The Trusselator technology is a key element of TUI's "SpiderFab" architecture, which will enable on-orbit fabrication of huge antennas, high-power solar arrays, and other systems not possible with current technologies."
The ability to build structures in space on-the-fly has implications for dreams of colonization. Net structures being built by the Trusselator could be used as supply depots for missions to Mars. While the concept may sound like something out of Star Wars, we're still far, far way from having the ability to complete something as ambitious as the Death Star.