Carbon dioxide snow to clean spatial telescope

An interesting method to keep the Webb Space Telescope mirror, seven times larger than Hubble, spotless.
The James Webb Space Telescope is the scientific successor to NASA’s Hubble Telescope. In order to capture light from 13.5 billion light-years away, its mirror, seven times larger than Hubble, must remain spotless.

The engineers’ technique to keep it clean involves shooting carbon dioxide snow on the mirror. Crystals knock contaminate particulates or molecules off the mirror without scratching it.

Led by NASA in collaboration with the European Space Agency and Canadian Space Agency, the Spatial Telescope should be launched in 2018.

CryoGas International (July 2015)