James Webb Space Telescope gets struck by micrometeoroid; Will it affect NASA's mission?

The multi-billion-dollar space observatory, the James Webb Space Telescope, was recently hit by a micrometeoroid at its location at the second Lagrange point (L2), NASA revealed. The agency said that the incident occurred between May 23-25 when a tiny rock struck Webb’s primary mirror, which is composed of 18 hexagonal segments. While this was the first time Webb encountered a micrometeoroid, scientists say that the bombardment will continue throughout the entirety of the telescope’s lifetime. 

Webb, which will build on the success of the Hubble space telescope, is built at a cost of $10 billion with a joint work of NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA) and is just a few weeks from the beginning its operations.

Will the micrometeoroid impact harm Webb?

In its recent update, NASA said that although the effect was marginally detectable, it caused no harm to the telescope as it is still performing at a level that exceeds all mission requirements. And since scientists knew about the frequent micrometeoroid impacts, Webb’s mirror has been engineered to withstand the bombardment. These events were anticipated when building and testing the mirror segments on the ground as a result of which its performance is still well above expectations.

During the development of the telescope, the engineers ran simulations and actual test impacts on the primary mirror in order to prepare it for its orbit at L2. The second Lagrange point is where Webb currently is installed, and according to NASA, this is an environment for micrometeoroids as dust-sized particles fly at extreme velocities around here. 

"We always knew that Webb would have to weather the space environment...and occasional strikes by micrometeoroids within our solar system,” said Paul Geithner from NASA's Goddard Space Flight Center.

"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."

As for the impacts in the future, NASA says that mission teams can minimize the effect of impacts by adjusting the mirror segments. They can also use protective maneuvers that intentionally turn the optics away from known meteor showers before they are set to occur. The recent impact was not a result of a meteor shower but was what NASA calls, "an unavoidable chance event". Notably, the agency has now formed a team of engineers especially to find ways to mitigate the effects of further micrometeoroids of a similar scale.