NASA announced Wednesday that a high-speed, dust-sized micrometeoroid crashed into one of the 18 James Webb Space Telescope primary mirror segments. This caused a noticeable but subtle effect on the segment’s performance. This was the fifth such impact since Webb's Christmas Day rocket.
Engineers expected to see random space dust hits over the lifetime of the observatory's $10 billion telescope. However, the impact between May 23-25 was greater than what pre-flight models had predicted.
Engineers analyzed the C3 mirror's performance after impact and sent commands to actuators to reposition the mirror. This helped to counteract most of the impact's effects, but not all. NASA stated that the telescope still operates better than it was before the impact.
NASA posted in a blog that "after initial assessments, NASA found that the telescope was still performing at a level which exceeds all mission requirements." "Thorough analysis is ongoing and measurements are being made."
James Webb Space Telescope, the most sophisticated and sensitive infrared observatory, has been launched. It is equipped with a 21.3-foot-wide segmented primary mirror that can detect faint, stretched-out light from galaxies and stars, which began to shine in the wake the Big Bang.
Each hexagonal sub-mirror in the beryllium primary mirror measures 4.3 feet in diameter. They are coated with a thin layer gold to increase reflectivity. These optical elements are some of the best ever designed. The highest bump in a segment would only be 2 inches high if it were scaled to North America.
Webb's four science instruments have not been affected by the micrometeoroid impact. NASA will unveil the first color images of the telescope's telescope on July 12, just as it had previously planned.
Lee Feinberg, Webb optical telescope manager at NASA's Goddard Space Flight Center said that the team had "anticipated that occasionally micrometeoroid impact would gracefully reduce telescope performance over time."
"Since launch we have had four smaller micrometeoroid hits that were consistent with our expectations, and this one more recently which is larger than what our degradation predictions predicted."
He stated that engineers and scientists would use the data to refine their models and "develop operational strategies to ensure we maximize Webb's imaging performance for many years."
Webb's 18-segment primary was built to resist micrometeoroid impacts by dust-size particles that are whizzing around the solar system. To better understand the threat to the telescope's image-degrading capabilities, simulations were run with actual mirror impacts before launch.
Engineers can reposition each segment with great precision. This allows them to counteract distortion caused by significant impacts after carefully studying the reflected light. NASA stated that not all degradation can be reversed by this method.
NASA managers have assured that the telescope is capable of weathering any environment by using the most current models and protecting it from meteor showers.
