The amount of space debris in the near-earth orbit is already estimated at hundreds of millions of fragments. The main danger of these “high-tech” debris lies in their speed – more than 28,000 km / h. Even a small piece at this speed can cause serious damage and even disable an operating spacecraft.
Until collisions are avoided, thanks to the constant monitoring carried out by space agencies using a system of ground-based telescopes and laser radars.
Engineers at the Faculty of Aeronautics at the Massachusetts Institute of Technology (MIT) have developed a laser sensing technique that can be used to determine not only the location of space debris, but also some of its characteristics. Now, for example, it became possible to identify the metal fragment, as well as the presence of paint on it.
One of the methods is called “laser polarimetry.” It makes it possible to measure the polarization of light reflected from various objects.
For example, when the sun’s rays are reflected from 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 oscillate and even deflect. The same material can have several polarization variants depending on the angle at which light falls.
The detailed identification of space debris will help to more accurately assess the danger that it poses primarily to the ISS crews and promptly warn them about it.