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An ESA-funded scientist is developing a magnetic space tug to combat the growing problem of space debris. The tugs could lock onto derelict satellites and deorbit them before they become a hazard to navigation, and because they use cryogenic magnets, they wouldn't have to even touch the derelicts and the targets wouldn't need to be specially modified for towing.
Depending on how it's defined, there are over 500,000 pieces of debris or "space junk" orbiting the Earth, ranging in size from old launch vehicles and dead satellites down to flecks of paint. Because they travel at tens of thousands of miles per hour, even the smallest object can strike with the force of a meteor, and if a large one should hit a satellite, the impact could turn them both into deadly clouds of shrapnel.
Funded by ESA's Networking/Partnering Initiative, Emilien Fabacher of the Institut Supérieur de l'Aéronautique et de l'Espace at the University of Toulouse has come up with a system using magnetic fields generated by superconducting wires cooled to cryogenic temperatures. For his PhD research, he has been using a rendezvous simulator with magnetic interaction models to study how to guide, navigate, and control such tugs.
"With a satellite you want to deorbit, it's much better if you can stay at a safe distance, without needing to come into direct contact and risking damage to both chaser and target satellites," says Fabacher. "So the idea I'm investigating is to apply magnetic forces either to attract or repel the target satellite, to shift its orbit or deorbit it entirely."
(Score: 1, Interesting) by Anonymous Coward on Tuesday June 27 2017, @10:31PM (2 children)
Launching something up there is not workable. The energy requirement is absurd, the materials cost is absurd, and you'll only end up making more space junk as the garbage collector devices collide with stuff.
Lasers work in multiple ways. You get light pressure, vaporization, and the thrust generated as bits of surface material boil off or explode off as ions.
The place to install the lasers is where the power can be generated. Put a laser at each large power plant. (hydro, nuke, coal, natural gas... the usual)
Consider the USA doing this. As a bit of debris rises over the west coast, all lasers on that coast fire at it. Continuing across the country, each laser begins firing as soon as the debris is suitably above the horizon.
The use of multiple lasers is important. With a single laser, output power is limited by the air. Air molecules rip apart and generally mess with the beam. With numerous lasers, each can be below the limit. The only limit is some sort of quantum vacuum thing, which is quite a lot of power. Pulsing the lasers can be helpful. This reduces the amount wasted on heating a gas cloud. It is possible for an intense pulse to strip multiple electrons from each surface atom, causing the resulting ions to leave the surface with a good deal of energy. This gets you thrust, which will slow the object to deorbit it. It also does a fine job of vaporizing objects.
(Score: 2) by bob_super on Tuesday June 27 2017, @11:40PM
The other reason to use multiple lasers spaced far apart is to only have the energy on the target, not on everything that passes behind it in the direction the laser is pointing at.
I'm pretty sure the NRO would still object.
(Score: 2) by unauthorized on Wednesday June 28 2017, @12:06AM
The problem with blasting stuff from Earth is that you need a really damn accurate laser in order to avoid accelerating the object along the radial axis, which could increase it's reentry speed substantially or possibly even blast it into solar orbit. In order to slow down the object, you need to heat up the side that is facing in a direction opposite of it's current momentum. This is not a problem if your laser has a higher orbit than the junk piece, because you can aim your laser at it when it's moving towards the laser satellite.