How Do You Clean an $8 Billion Telescope? With High-Speed Snowballs


When it comes to cleaning an $8.8 billion space telescope designed to see farther into the universe than humans have ever been able to before, you can’t just break out a few Clorox wipes. You can, however, blast it with snow. 

The James Webb Space Telescope, the NASA-born successor to Hubble, is set to launch in 2018 as a collaboration between the American space agency and its counterparts in Europe and Canada. With infrared capabilities and a mirror that will be seven times larger than Hubble’s, NASA touts it as the most powerful telescope ever built, able to see 13.5 billion light-years away. 

Although the telescope is being assembled in a world-class cleanroom at the Goddard Space Flight Center in Maryland—an environment designed to keep particles from landing on the telescope and its instruments—it still might need to be dusted off if it somehow becomes contaminated during testing. 

One of the mirrors for the James Webb Space Telescope arrives at Goddard's cleanroom for assembly.

"Small dust particles or molecules can impact the science that can be done with the Webb," Lee Feinberg, NASA’s optical telescope element manager (read: master of some of the world's most valuable lenses) explains in a press statement. "So cleanliness especially on the mirrors is critical."

To clean the sensitive gold mirror, NASA engineers are developing a method of snow cleaning, which they piloted on a special test version of the mirror (see top image). Engineers shoot a high-speed carbon-dioxide liquid that freezes when it hits the mirror, turning into snow-like flakes. The gentle snowflakes brush aside any contaminants (particles of dust, etc.) that might have settled on the lightweight folding mirror segments without scratching. Bring on the super clean snowball fights! 

[h/t: Smithsonian]

All images courtesy NASA/Chris Gunn