Collisions in Low Earth Orbit: The Kessler Effect

Pollution
STEM
Edward Hessler

Have you ever heard of the Kessler effect, also known as collisional cascading?  I hadn't.

It is a density effect. When the number of objects in low earth orbit (LEO) becomes high enough  collisions would result in a  cascade of collisions. This is known as an unstable debris environment. The hypothesis was first proposed by NASA scientist, Donald J. Kessler in 1978.

The estimate is that there are some 700,000 objects larger than 1 cm and 170 million larger than 1 mm residing in Earth orbit. It is crowded out there.

Space debris [Wikimedia] 

The topic is an active area of research and was the subject of a recent conference. The film, Space Debris: A Journey to Earth was produced for the 7th European Conference on Space Debris, 18-21 April 2017. LEO looks very messy.

Warning. The volume overwhelms the narration at times.

The International Space Station has been in orbit for more than 15 years. There have been four times when crew members were ordered to take emergency shelter in the space capsule attached to the space station.

Here is a photograph of a window chip caused by a collision. It was taken by British astronaut Tim Peake when he was a crew member on the International Space Station.