NASA’s new powerful space observatory, the James Webb Space Telescope, was launched by a larger than expected micrometeoroid in late May, causing some detectable damage to one of the spacecraft’s 18 primary mirror segments. The impact means that the mission team must correct for the distortion created by the strike, but NASA says the telescope “continues to perform at a level that exceeds all mission requirements.”
NASA’s James Webb Space Telescope, or JWST, is the agency’s incredibly powerful next-generation space telescope, designed to look into the outer reaches of the universe and look back in time to the stars and galaxies formed just after the Big Bang. It cost NASA nearly $ 10 billion to build and more than two decades to complete. But on Christmas Day 2021, the telescope was finally launched into space, where it underwent an extremely complex unfolding process before reaching its final destination about 1 million miles from Earth.
Since its launch, JWST has already been hit by at least four different micrometeoroids, according to a NASA blog post, but all of these were small and about the size of what NASA expected the observatory to meet. A micrometeoroid is usually a small fragment of an asteroid, usually smaller than a grain of sand. However, the one that hit JWST in May was larger than the agency had prepared for, although the agency did not specify the exact size. NASA admits that the strike, which took place between May 23 and May 25, has caused a “marginally detectable effect in the data”, and that engineers continue to analyze the effects of the impact.
NASA expected that JWST would be hit by small space particles during its lifetime; fast-moving spots of space rock are just an inevitable feature of the deep space environment. In fact, NASA designed the telescope’s gold-plated mirror to withstand strikes by small remnants of space over time. The space agency also conducted a combination of simulations and ground testing with mirror tests to find out how best to strengthen the mirrors to withstand micrometeoroid impacts. However, NASA says that the models they used for these simulations did not have such a large micrometeoroid, and it was “beyond what the team could have tested on the ground.”
Still, this does not come as a total surprise. “We have always known that Webb would have to withstand the space environment, which includes strong ultraviolet light and charged particles from the sun, cosmic rays from exotic sources in the galaxy and sporadic attacks from micrometeoroids in our solar system,” said Paul Geithner, technical deputy project manager at NASA’s Goddard Space. Flight Center, said in a statement.
Engineers have the ability to also maneuver JWST’s mirrors and instruments away from storms of space debris, if NASA can see them coming. The problem, however, was that this micrometeoroid was not part of a shower, so NASA considers it an “unavoidable coincidence.” Nevertheless, the agency is forming an engineering team to come up with ways to potentially avoid or reduce the impact of micrometeoroid attacks of this magnitude. And since JWST is so sensitive, the telescope will also help NASA gain a better understanding of how many micrometeoroids there are in the deep space environment.
Despite the strike, NASA remained optimistic in its post on JWST’s future. “Web’s achievement at the beginning of life is still well above expectations, and the observatory is fully capable of performing the science it was designed to achieve,” according to the blog. Engineers can also adjust the affected mirror to help eliminate data distortion. The assignment team has already done this and will continue to tinker with the mirror over time to get the best results. It is a process that will take place through JWST’s planned five to ten years of life as new observations are made and events unfold. Simultaneous, NASA warns that engineers will not be able to completely cancel the impact of the strike.
NASA engineers had to build the JWST to be incredibly robust since the telescope is alone in space. Unlike its predecessor, the Hubble Space Telescope, which is currently in orbit around the Earth, the JWST was not designed to be usable. This means that if something significant breaks down on the spacecraft, engineers must troubleshoot a way to fix it from the ground. There is currently no option to send humans or a robotic spacecraft to fine tune the JWST. This means that JWST must live with the slightly damaged mirror until the end of the mission, and NASA expects that the spacecraft will be hit by even more debris over time.
In the meantime, the strike does not appear to be affecting JWST’s schedule. In fact, the news of this micrometeoroid comes just a month before a major milestone for the mission. After spending the last few months fine-tuning JWST’s instruments and fine-tuning the spacecraft’s mirrors, the mission team is set to unveil the first full-color images from JWST on 12 July. NASA will not say what the images will be, but they should be spectacular.