November 16 () –
NASA has set out a strategy to protect the Webb Space Telescope from the impact of micrometeorites and ensure that all parts of the observatory continue to function at their best.
Specifically, it has been defined micrometeor avoidance zone (MAZ), that overlaps part of the field of observation of the space telescope.
The telescope’s 6.5-meter main mirror, located 1.5 million kilometers from Earthhas recorded 14 measurable micrometeorite impacts, averaging one or two per month. Only one impact recorded in May it passed the design tests of the observatory, although its performance did not decrease.
To ensure all parts of the observatory continue to perform at their best, NASA convened a working group of optics and micrometeorite experts from the Webb team at NASA Goddard, the maker of the telescope’s mirror, the Space Telescope Science Institute and the NASA Meteoroid Environment Office at NASA’s Marshall Space Flight Center in Huntsville, Alabama.
After extensive analysis, the team concluded that the highest-energy impact observed in May was a rare statistical eventboth in terms of energy and impact at a particularly sensitive location on Webb’s primary mirror.
“Micrometeoroids hitting the mirror head (moving in the opposite direction that the telescope is moving) have twice the relative velocity and four times the kinetic energy, so avoiding this direction when feasible will help extend the exquisite optical performance for decades,” said it’s a statement Lee Feinberg, director of Webb telescope optics at NASA Goddard.
This does not mean that these areas of the sky cannot be observed, just that observations of those objects will be more safely made at a different time of year when Webb is at a different location in its orbit. Observations that are time critical, such as solar system targets, will still be made in the micrometeor avoidance zone if necessary. This adjustment of how Webb observations are scheduled will have statistical benefit in the long run.
The team will implement the micrometeorite avoidance zone starting in Webb’s second year of science, or “Cycle 2”.
