Webb sustains micrometeoroid impact; NASA says impact was larger than expected

In May 2022, NASA's James Webb Space Telescope was hit by a micrometeoroid that the agency says was larger than the observatory was tested for. Despite this 'rare statistical event', the telescope is fully capable of performing the science it was designed to achieve.

"We have experienced 14 measurable micrometeoroid hits on our primary mirror, and are averaging one to two per month, as anticipated. One of these was higher than our expectations and prelaunch models; however, even after this event our current optical performance is still twice as good as our requirements," said Mike Menzel, Webb lead mission systems engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland.

According to NASA, Webb was built to withstand continual bombardment from these dust-sized particles moving at extreme velocities, to continue to generate groundbreaking science far into the future.

To minimize future impacts of this magnitude, a team of optics and micrometeoroid experts from NASA Goddard's Webb team, the telescope's mirror manufacturer, the Space Telescope Science Institute, and the NASA Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Alabama, has decided that future observations will be planned to face away from what are now known as 'micrometeoroid avoidance zones'. The team will implement the micrometeoroid avoidance zone starting with Webb's second year of science, or Cycle 2.

Our team is taking steps to make this rare event even more unlikely. Webb will still see the full sky over the course of its orbit, but observations that face micrometeoroid “zones” will be rescheduled to when Webb can more safely make them from a different location in its orbit.

— NASA Webb Telescope (@NASAWebb) November 15, 2022

Observations that are time critical, such as solar system targets, will still be carried out in the micrometeoroid avoidance zone if needed, the agency said on Tuesday.