NASA said today that one of the segments of the primary mirror of the Webb Space Telescope was hit by a micrometeoroid, a small fragment of an asteroid, between May 23 and 25. Initial assessments of the telescope found that the spacecraft was still functioning exceptionally well, although the effects of the impact were felt in recent data readings.
Micrometeoroids are extremely small (dust-sized) space debris that move rapidly. They are a common part of a hostile space environment that will bombard the Webb telescope throughout its years of operation.
“With Webb mirrors exposed in space, we expected the occasional impact of micrometeoroids to gracefully degrade the telescope’s performance over time,” Lee Feinberg, NASA’s Webb Optical Telescope Elements Manager, said in a statement. agency statement. “Since the launch, we’ve had four strokes of smaller measurable micrometeoroids that were consistent with expectations, and this one, more recently, is larger than our degradation predictions assumed.”
Webb arrived at L2, its observation point in space, in late January. L2 is a million miles from Earth, but that doesn’t mean the telescope is just coming out of empty space. In contrast, the telescope is in a dynamic part of the solar system that comes with a host of hostile space weather phenomena. In addition to micrometeoroids, there are cosmic rays, charged solar winds, and ultraviolet radiation, all of which can damage spacecraft.
Fortunately, Paul Geithner, NASA’s Deputy Technical Director of Projects, said in the statement that “We designed and built Webb with a range of performance (optical, thermal, electrical, mechanical) to ensure that it can carry out its ambitious scientific mission even after many years in space. ”
Webb mirrors are perhaps the most essential component of the $ 10 billion spacecraft. Mirrors are the ones that focus the light of the cosmos, allowing Webb images of everything from nearby exoplanets to the oldest light sources in the universe. After the telescope reached L2, the mirror went through a long period of alignment; in early May, Webb scientists said the alignment of the mirrors was perfect.
When Webb was built, its engineers designed mirrors to handle micrometeoroids like the one that recently impacted one of the segments. The telescope can adjust the positions of the mirror to correct the impacts of micrometeoroids, minimizing the effects that these collisions can have on the telescope’s image.
Larger events, such as meteor showers, are a major nuisance, but the telescope can be aimed away from those events to protect its optical equipment, NASA said in a statement. The team, and therefore Webb, seems to be well prepared for the space conditions on L2.
The first full-color images of the telescope are expected on July 12; Although NASA has not announced what Webb will do, we know that the images will capture one of the telescope’s main scientific targets. A pair of dusty micrometeoroids from old mirrors will not stop the flagship telescope from starting its scientific operations this summer.
More: The last image shows the impressive power of the Webb Space Telescope
Editor’s Note: Release dates for this article are based in the US, but will be updated with local Australian dates as soon as we know more.