A supply ship deployed by the Japanese Aerospace Exploration Agency (JAXA) burned in the Earth’s atmosphere during its descent from an unsuccessful mission. The Kounotori Six craft was deployed into space over one week ago, and was part of a trial experiment aiming at cleaning up the scores of potentially hazardous debris orbiting Earth. The 30×14-foot ship initially transported lithium-ion batteries along with other goods and resources to the International Space Station (ISS) without incident, before shifting gears to its next task.
The Kounotori Six was supposed to deploy an electrodynamic tether that measured about a half-mile in length, which was composed of stainless steel and aluminum wiring and strands. Kounotori Six’s tether was also coated with a lubricant that was designed to stimulate electric conductivity. The tip of the tether contained a 48-pound end mass that would attach to a piece of debris, which along with the interaction between the tether’s electrodynamics and Earth’s electromagnetic field, would thwart the piece’s orbital path into the planet’s atmosphere where it would burn. Primarily geared towards derailing the orbits of space junk like discarded rocket stages and defunct satellites, the Kounotori Six’s electrodynamic tether would have had the same alluring effect on smaller debris pieces as well.
According to JAXA, the half-mile tether failed to even deploy when one of its four bolts attached to the spacecraft did not release, despite receiving commands to do so. Scientists eventually abandoned their efforts after spending several hours trying every conceivable method to extend the tether. It was at this time when the Kounotori Six was directed to plummet into the Earth’s atmosphere where it disintegrated. This is the third mission involving the deployment of an electrodynamic tether that’s blown up in scientists’ faces. Dating back to the 1990s, one tether broke during deployment, while a second failed to fully extend.
The growing number of space debris has become increasingly problematic as more junk that’s discarded from space missions, orbits around Earth. It’s estimated there are around two million pieces of space debris revolving around Earth whose dimensions range from less than an inch, to several meters. It’s believed only 500,000 pieces of debris larger than half an inch are being tracked out of an estimated two million revolving around Earth. The risk is quite evident for the 800+ satellites that are locked in low-hanging orbits, and for larger spacecraft like the ISS. Considering how most debris can travel at speeds up to 17,500 mph, a piece smaller than a half-inch can have catastrophic consequences if it were to strike the International Space Station or a low-hanging satellite.
Filed Under: Aerospace + defense