One of the James Webb Space Telescope’s primary mirror segments was struck by a micrometeoroid and while it has been damaged, NASA says it’s not cause for alarm and the telescope is still on schedule.
The impact occurred between May 23 and May 25 and was reported to the public last week. Despite the impact on one of its primary mirrors — the system Webb uses to make its observations — NASA says that the telescope is still performing at a level that exceeds all mission requirements despite a “marginally detectable” effect in the data.
Space is a chaotic and difficult to predict environment, and NASA says that impacts on the multi-billion dollar telescope aren’t just going to happen, but they are expected.
“Impacts will continue to occur throughout the entirety of Webb’s lifetime in space; such events were anticipated when building and testing the mirror on the ground,” NASA says.
The space agency says that Webb’s mirror was engineered to withstand bombardment from micrometeoroids, as the environment it orbits is filled with dust-sized particles that fly around at extreme velocities.
“We always knew that Webb would have to weather the space environment, which includes harsh ultraviolet light and charged particles from the Sun, cosmic rays from exotic sources in the galaxy, and occasional strikes by micrometeoroids within our solar system,” Paul Geithner, technical deputy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, says.
“We designed and built Webb with performance margin — optical, thermal, electrical, mechanical — to ensure it can perform its ambitious science mission even after many years in space.”
In late May, Webb sustained a dust-sized micrometeroid impact to a primary mirror segment. Not to worry: Webb is still performing at a level that exceeds all mission requirements. Our first images will #UnfoldTheUniverse on July 12: https://t.co/9jp0uq7ytS pic.twitter.com/VKkSp16yrg
— NASA Webb Telescope (@NASAWebb) June 8, 2022
“Micrometeoroid strikes are an unavoidable aspect of operating any spacecraft, and we expect that impacts will continue to occur throughout Webb’s lifetime,” NASA Webb Telescope team wrote on Twitter. “Our team built and tested the mirror on the ground anticipating such events.”
NASA says that while Webb was being built, engineers used a mixture of simulations and actual test impacts on mirror samples to get an idea of how the telescope would respond to impacts in space and study how to make sure that it would continue to operate within expectations when it inevitably would be. And while NASA says that this impact was larger than the scientists tested for — and beyond what the team could have tested on the ground — the space agency is confident that Webb can continue to perform as designed.
The impact was not the result of a meteor shower and is considered to be an unavoidable “chance event.” NASA says that as a result of the impact, a team of engineers has been formed to look at ways to mitigate the effects of further impacts by micrometeoroids at this scale.
Webb’s mirrors can be adjusted to correct for the damage, and NASA says that they have been able to adjust the affected segment to cancel out a portion of the distortion that was caused by the impact.
So while NASA is working to make sure that future impacts don’t cause any major problems to Webb, this first impact has caused no change to Webb’s operating schedule and the plan to capture its first full-color photo this summer nor its first scientific observations.