When a rocket sends a capsule up with supplies for the International Space Station, they usually send a bunch of their trash back down with it, all of which burns up in the atmosphere on re-entry. But as long as you’ve got that (doomed) vehicle up there, you might as well do some science with it along the way. And that’s exactly what the Japanese Space Agency (JAXA) is doing with their Kounotori 6 supply ship that just left the ISS on Friday.
The experiment is with an electromagnetic tether that can be used to either turn electrical energy into kinetic or vice-versa. When you string a long conducting wire outwards from earth, the two ends pass through the earth’s magnetic field at different altitudes and thus pass through magnetic fields with different strengths, and an electrical potential is generated. In the KITE experiment (translated), a resistive load and an electron emitter on the supply ship are designed to burn up this electrical energy, lowering the ship’s kinetic energy, and dropping its orbit down to earth.
The eventual plan is to use a tether system like this to remove kinetic energy from space junk, pulling it out of orbit and out of harm’s way without requiring the ship to carry extra fuel to do so. The seven-day test mission will investigate thrust and current generated by the 700-meter-long aluminum wire, as well as experimenting with controlling it as it unfurls. The video, embedded below, makes it look like they’re going to actively control the load to stabilize the end of the tether relative to the ship. Anyone want to chime in on that? This isn’t the first time an electrodynamic tether has been tested in space, but with some luck, it will be the first successful test in orbit.
This is definitely not a hack, and the science is really cool. But cleaning up the space junk with a freighter that’s bound to burn up in the atmosphere is a win. The ISS gets rid of its metaphorical dirty laundry, which is mostly expended batteries, and the orbit gets cleaned up to boot. We wish them the best of luck.
Via [Spaceflight Now].