The concept of this artist shows the fully deployed James Webb Space Telescope in space. Credit: Adriana Manrique Gutierrez, NASA animator
NASA’s James Webb Space Telescope crashed in one of its main mirror segments between May 23 and 25.
Our solar system is full of small particles of rock or metal called micrometeoroids. These small meteoroids usually weigh less than a gram, but still pose a significant threat to spacecraft, as their average speed relative to orbit is a staggering 22,500 miles per hour (10 kilometers per second).
Micrometeorological shocks are an inevitable aspect of the operation of any spacecraft that routinely suffers many impacts during long and productive scientific missions in space. Between May 23 and 25, NASA’s James Webb Space Telescope was hit in one of its main mirror segments.
After initial assessments, the team found that the telescope was still operating at a level that exceeded all mission requirements, despite a slight effect in the data. In-depth analysis and measurements continue. Impacts will continue to occur throughout the Web’s life in space; similar events were foreseen in the construction and testing of the ground mirror. After successfully launching, deploying and aligning the telescope, Webb’s early life work is still well above expectations and the observatory is fully capable of carrying out the science for which it was designed.
The Web mirror is designed to withstand the bombardment of the micrometeorological environment in its orbit around the Sun-Earth L2 by dust-sized particles flying at extreme speeds. While the telescope was being built, the engineers used a mixture of simulations and actual test effects on mirror samples to get a clearer idea of how to strengthen the orbiting observatory. This latest impact was greater than modeled, and beyond what the team could test on the ground.
“We’ve always known that the Web will have to withstand a space environment that includes harsh ultraviolet light and charged particles from the sun, cosmic rays from exotic sources in the galaxy and accidental micrometeroid impacts in our solar system,” said Paul Geithner, deputy technical director. of the project at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We designed and built Webb with a margin of productivity – optical, thermal, electrical, mechanical – to ensure that it can fulfill its ambitious scientific mission even after many years in space.
For example, due to the careful work of the launch site teams, Web optics were kept cleaner than necessary while on the ground; their pure purity improves the overall reflectivity and transmittance, thus improving the overall sensitivity. This and other performance margins make Webb’s scientific capabilities strong to the point of potential deterioration over time.
In addition, Webb’s ability to sense and adjust the positions of the mirrors allows partial adjustment of the impact result. By adjusting the position of the affected segment, engineers can eliminate some of the distortion. This minimizes the effect of any impact, although not all degradation can be reversed in this way. Engineers have already made the first such adjustment for the recently affected C3 segment, and additional planned mirror adjustments will continue to refine this adjustment. These steps will be repeated when necessary in response to future events as part of the telescope’s observation and maintenance during the mission.
To protect the Web in orbit, flight crews can use defensive maneuvers that deliberately divert optics from known meteor showers before they occur. This most recent impact is not the result of meteor showers and is currently considered an inevitable accident. As a result of this impact, a specialized team of engineers has been formed to look for ways to mitigate the effects of further micrometeorological shocks of this magnitude. Over time, the team will collect invaluable data and work with micrometeorological forecasting experts at NASA’s Marshall Space Flight Center to better anticipate how productivity may change, given that the initial telescope performance is better than expected. Webb’s enormous size and sensitivity make it an extremely sensitive micrometeorite detector; Over time, Webb will help improve environmental knowledge of the solar particulate matter in L2, for this and future missions.
“With Web’s mirrors in space, we expected accidental micrometeorological impacts to gracefully impair the telescope’s performance over time,” said Lee Feinberg, NASA’s Goddard Optical Telescope Element Manager. “Since launch, we have had four smaller measurable micrometeorological shocks that were in line with expectations and the recent one, which is larger than our degradation forecasts. We will use this flight data to update our performance analysis over time, as well as to develop operational approaches to ensure that we maximize Webb image performance to the best possible extent for many years to come.
This recent impact has not led to a change in the timing of Webb’s operations, as the team continues to test the monitoring modes of scientific tools and prepare for the release of the first images of Webb and the start of scientific operations.
Add Comment