The amount of space debris in near-earth orbit is already in the hundreds of millions of fragments. The main danger of these "high-tech" debris lies in their speed - over 28, 000 km / h. Even a small piece at this speed can cause serious damage and even disable a functioning spacecraft.
So far, collisions have been avoided thanks to constant monitoring by space agencies using a system of ground-based telescopes and laser radars.
Engineers in the Aeronautics Department of the Massachusetts Institute of Technology (MIT) have developed a laser sensing technique that can determine not only the location of space debris, but also some of its characteristics. Now, for example, it has become possible to identify a metal fragment, as well as the presence of paint on it.
One of the methods is called "laser polarimetry". It allows you to measure the polarization of light reflected from various objects.
For example, when the sun's rays are reflected off a rubber ball, the electric field of the incident light can oscillate vertically. However, if the surface of the ball has irregularities, then the reflected light will begin to vibrate and even deflect. The same material can have several polarizations depending on the angle at which the light is incident.
Detailed identification of space debris will help to more accurately assess the danger it poses, first of all, to the ISS crews and promptly warn them about it.