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Japan Sends Its New Space Junk-Fighting Technology To The ISS (phys.org)
What floats 249 miles in the sky, stretches 2,300 feet, and took over 10 years to develop?
An anonymous reader quotes Phys.org:
Japan launched a cargo ship Friday bound for the International Space Station, carrying a
"space junk" collector that was made with the help of a fishnet company... Researchers are using a so-called electrodynamic tether made from thin wires of stainless steel and aluminum... The electricity generated by the tether as it swings through the Earth's magnetic field is expected to have a slowing effect on the space junk, which should, scientists say, pull it into a lower and lower orbit. Eventually the detritus will enter the Earth's atmosphere, burning up harmlessly long before it has a chance to crash to the planet's surface.
Bloomberg has some interesting background: The experiment is part of an international cleanup effort planning to safeguard astronauts and about $900 billion worth of space stations, satellites and other infrastructure... Satellite collisions and testing of anti-satellite weapons have added thousands of debris fragments in the atmosphere since 2007, according to NASA... With debris traveling at up to 17,500 miles an hour, the impact of even a marble-size projectile can cause catastrophic damage.
Bloomberg has some interesting background: The experiment is part of an international cleanup effort planning to safeguard astronauts and about $900 billion worth of space stations, satellites and other infrastructure... Satellite collisions and testing of anti-satellite weapons have added thousands of debris fragments in the atmosphere since 2007, according to NASA... With debris traveling at up to 17,500 miles an hour, the impact of even a marble-size projectile can cause catastrophic damage.
Relative to the centre of the Earth, which can be considered stationary for this frame of reference.
A spot at sea level on the equator is moving about 1000 miles an hour in the same frame of reference.
17,500 mph is the same speed as the ISS. At the distance of 22,236 miles, where the telecommunications satellites are, that drops to 6876 mph.
The Space Station isn't going to be doing anything to space junk, except trying to avoid it. The supply craft is carrying this tether device to test its performance. After it drops off its payload at the Space Station and detaches, before it is de-orbited, it will unspool this tether and see if the electrodynamic drag produced matches predictions.
TFA isn't clear, and mixes terminology. The summary seems to say this will act like a net to remove many little particles, but the technology is a single tether line.
As I recall, years ago there was a tether test that generated so much power (moving through the Earth's magnetic field) that it shorted out part of the test satellite. The goal of that test, if memory serves, was to use the tether as a propulsion/braking system. Run power through to go faster, drain power out for braking. Presumable a resistance coil / heater.
If this is that same technology, it isn't going to do anything for debris that isn't already captured or attached to the tether. Keeping a dead satellite from becoming space junk is good, but this won't help with the countless particles out there already.