Debris in space is threatening a lot of valuable missions and endangering lives.
Today’s invention is intended as a possible contribution to cleaning up the mess before it gets bad enough to cause a communications blackout or a fatal accident.
A number of long metal tubes is placed in orbit. They would be of different diameters and with one end closed. These would be repositioned radially, using traditional thrusters, but always aligned circumferentially so as to admit small items of debris into the leading, open end. A detection system would be carried which could spot and avoid oncoming items bigger than a certain fraction of the tube bore.
Smaller crumbs would be involved in a series of glancing collisions with the interior wall of a tube, causing their relative motion to decrease and heating the tube by this frictional contact (but without damaging or deflecting the tube significantly).
The heat generated would be used to power the thruster and imaging system. The tubes would gradually harvest the fragments they came across at each radius. Eventually, each tube would be effectively full and forced to fall from orbit, incinerating itself and its contents completely on re-entry.