Webb Telescope Chipped by Meteoroid Before It Goes Live

So far, things have been going a lot better than all the engineers expected with the new James Webb Space Telescope. All the tricky feats of magic they had to pull off proceeded flawlessly. The challenge was to get the massive gold-plated mirror segments into the proper orbit, assembled and aligned. Just as the fancy new telescope was about to go on the job, a random piece of space rock chipped one of the mirrors. It’s kind of like getting your brand new Maserati dented by a shopping cart. It still performs like a champ even with the infuriating flaw.

 Webb Expects the unexpected

Space fans have learned that things like this can happen when you least expect it. This time around the damage can be worked around with software fixes. Soon after the Hubble Space Telescope was deployed, the one which Webb is replacing, Hubble’s mirror unexpectedly warped from the temperature extremes. Engineers learned a lot about casting mirrors from that mistake because it was a doozy.

A set of lenses like eyeglasses had to be fitted to Hubble, by hand, to make it function. Once it had it’s spectacles, it brought us record breaking images. This time, the prognosis is a whole lot better.

According to NASA, “the damage from the dust-sized space rock was producing a noticeable effect in the $10 billion telescope’s data, but is not expected to limit the mission’s performance.” When the first images come out next month, there won’t be any difference at all in the “wow factor,” they promise.

Mark your calendar for July 12 to see the Webb telescope’s first official views of our universe. The release notes that the micrometeoroid struck between May 23 and 25. It did knock one mirror segment out of alignment but that won’t affect the work schedule. This isn’t the first space rock to impact. Actually, it’s the fifth but it was the largest.

Just like a BB shot at a window, “the impact left a ‘dimple‘ in the mirror segment known as C3 — one of the 18 beryllium-gold tiles.” When assembled together, those segments make a mirror 21 feet wide. Webb has been in “halo” orbit, parked at the Sun–Earth L2 point since December.

Since then, two test images have been released. The very first one wasn’t expected to show anything at all but ended up capturing images of some of the oldest galaxies ever seen by human kind.

Exceeds mission requirements

Engineers planned ahead for this sort of thing. The mirror “was engineered to withstand bombardment with dust-sized particles flying at extreme velocities in space, but the most recent impact was ‘larger than was modeled and beyond what the team could have tested on the ground.‘” They just keep their fingers crossed it doesn’t happen more often than expected and that nothing mission critical gets hit.

“After initial assessments, the team found the telescope is still performing at a level that exceeds all mission requirements.” They’re still measuring things and checking but the Webb team already started “a delicate readjustment of the impacted mirror segment to help ‘cancel out a portion of the distortion‘ caused by the micrometeoroid.”

Even with a chip in segment 13, Webb is still the most powerful space-based observatory ever built, hands down. It’s “suite of sensors and 18 gold-plated mirror segments working together” will survey exoplanets for signs of life and peer back to the earliest moments of our universe.

Like all random chance events, what happened here was a micrometeoroid which didn’t come from any known meteor shower. It was merely “an unavoidable chance event.” That’s one of the reasons why it has 18 separate hexagonal segments.

Hanging underneath and chilled to as close to absolute zero as they can get, are a cluster of various cameras and imaging devices allowing Webb to capture data in the full range of the infrared spectrum.

One of the two recently released images shows “slightly different views of the Large Magellanic Cloud, a small satellite galaxy of our Milky Way.” At first they don’t seem like much but when you compare them to the previous best images of the same astronomical feature, the HD difference is unmistakable.