NASA Shares Plan To Protect Webb Telescope After Surprise Micrometeroid Impact

NASA convened a team of experts to devise a plan to protect its extremely valuable Webb telescope from powerful micrometeoroid impacts. The team was assembled following an impact in May, which exceeded any prelaunch models.

NASA reported in June of this year that the Webb telescope had been struck by multiple micrometeoroids between May 23 and 25. While the space agency stated that it had anticipated strikes of that nature, one of the micrometeoroids delivered a more powerful impact than had been anticipated. The fifth impact recorded required engineers to adjust the instrument to compensate for the unexpected damage. Now, NASA has devised a plan to try and avoid any additional powerful impacts in the future to JWST.

"We have experienced 14 measurable micrometeoroid hits on our primary mirror, and are averaging one to two per month, as anticipated. The resulting optical errors from all but one of these were well within what we had budgeted and expected when building the observatory," explained Mike Menzel, Webb lead mission systems engineer at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Menzel added that while the impact exceeded expectations of prelaunch models, the observatory was still delivering performance twice as good as previous requirements.

Webb's mirrors were built to withstand micrometeoroids, which are unavoidable in space. In May, a dust-sized hit was larger than tested for. After careful analysis, we've found it to be a rare statistical event. Webb’s optical performance remains twice as good as requirements. ⬇️ pic.twitter.com/9WmNfwvk40

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

Following the impacts in May, NASA convened a group of optics and micrometeoroid experts from NASA Goddard's Webb team, the telescope's manufacturer, the Space Telescope Science Institute, and the NASA Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Alabama. The team studied the impacts that occurred and came to the conclusion that the "higher-energy impact observed in May was a rare statistical event both in terms of energy, and in hitting a particularly sensitive location on Webb's primary mirror."

In order to minimize future impacts of this enormity, the team decided that future observations will be conducted facing away from what is now known as the 'micrometeoroid avoidance zone.' By doing this, the team believes they can avoid unneeded direct impacts on the primary mirror. By being able to avoid strikes of this magnitude, the team hopes to extend the optical performance for decades, according to Lee Feinberg, Webb optical telescope element manager at NASA Goddard.

Feinberg went on to add, "This does not mean that these areas of the sky cannot be observed, only that observations of those objects will be more safely made at a different time in the year when Webb is in a different location in its orbit."

The upcoming changes are scheduled to be implemented beginning in Webb's second year of science, or "Cycle 2."