Irreversible space rock damage will not stop the Webb telescope from exceeding expectations

Irreversible space rock damage will not stop the Webb telescope from exceeding expectations

Yes, a small rock particle hit the Webb telescope. No, the mission is by no means doomed.

You may have read misleading headlines emphasizing that the James Webb Space Telescope – the most powerful such observatory ever built – has sustained any permanent damage. It’s a cherry-picked piece from a new 55-page report describing the instrument’s excellent scientific performance over the past six months, while engineers prepared and tested its unique cosmic viewing capabilities.

The web telescope is in good shape overall. Here’s what you should know about the state of the observatory that will revolutionize our understanding of the cosmos.


The James Webb Telescope’s first amazing cosmic images are here

What did the scientists conclude about the condition of the Webb telescope?

NASA and its partners, the Canadian Space Agency and the European Space Agency, concluded that Webb – even after a moving micrometeoroid (a small, often dusty rock particle) hit and caused a “significant uncorrectable change” in one of the telescope’s 18 gold-plated hexagonal mirrors – is “fully capable of achieving the discoveries for which it was built.”

It is crucial that they expect Webb to do so exceed expectations. “Besides, almost across the board, JWST’s scientific performance is better than expected,” Webb’s researchers wrote.

“The scientific performance of JWST is better than expected.”

Why is Webb expected to outperform? The mirrors are cleaner than necessary to meet the high scientific goals. Its guidance system, which locks in and tracks targets, is better than necessary. And its overall performance when clearly viewing objects is better than the requirements.

And if there was not enough good news, Webbs researchers have concluded that it has enough limited fuel on board to help drive the mission for 20 years. (The telescope used less fuel than planned to reach the outpost about 1 million miles from Earth.) NASA originally hoped the instrument would last for five years, and the agency was initially pleased to hear that it would operate with sufficient fuel for more than 10 years. year.

With the Web telescope on top, astronomers plan to:

  • Look at stars and galaxies that formed over 13 billion years ago, just a few hundred million years after the Big Bang. “We’re going to see the very first stars and galaxies ever formed,” Jean Creighton, an astronomer and director of the Manfred Olson Planetarium at the University of Wisconsin-Milwaukee, told Mashable last year.

  • Look at the cosmos in infrared light, which allows us to see far more of the universe. Infrared has longer wavelengths than visible light, so the light waves pass more efficiently through cosmic clouds; the light does not collide as often with and is scattered by these densely packed particles. Ultimately, Webb’s infrared vision can penetrate places that the legendary Hubble Space Telescope cannot.

  • Look into distant exoplanets: The Web Telescope carries specialized equipment, called spectrometers, which will revolutionize our understanding of these distant worlds. The instruments can indicate which molecules (such as water, carbon dioxide and methane) are present in the atmosphere of distant exoplanets – whether they are gas giants or smaller rocky worlds. Webb will look at exoplanets in the Milky Way. Who knows what we find?

How bad is the damage to Webb?

As you have read above, the telescope is in good shape.

During the six months that scientists prepared the $ 10 billion telescope for its long-awaited scientific operations, scientists discovered six impacts from micrometeoroids. In fact, they expected about one hit each month. “Inevitably, any spacecraft will encounter micrometeoroids,” the report noted. Of the six hits, five had insignificant effects.

However, the impact that occurred between 22 and 24 May was strong enough to cause, as mentioned above, a “significantly uncorrectable change” in one of Webb’s 18 hexagonal mirror segments (segment C3). Fortunately, the observatory’s mirror – which collects dim light from the extremely distant cosmos – is quite large at over 21 feet across. This means that most of the telescope is not affected.

mirror on the James Webb Space Telescope

The image to the right shows a bright area (bottom right of the mirror) where a micrometeroid hit the Webb telescope, and finally changed the surface of the mirror.
Credit: NASA / ESA / CSA

“But the effect was small at full telescope level because only a small part of the telescope area was affected,” Webb’s researchers wrote.

In addition, after the strike, Web engineers worked to make small adjustments to the mirror’s alignment, which limited any small image errors. (Such errors can be expected as the telescope drifts slightly in space.) “Web’s ability to detect and adjust mirror positions allows for partial correction of the result of a collision,” NASA noted earlier. “By adjusting the position of the affected segment, engineers can cancel out some of the distortion.”

What are the risks of future effects on the telescope?

Only time will tell whether this influence was rare, or whether it may be more common than Webb researchers estimated.

“It is not yet clear whether the May 2022 hit to segment C3 was a rare occurrence (ie an unfortunate early attack by a high kinetic energy micrometeoroid that can statistically occur only once in several years), or whether the telescope may be more exposed to damage by micrometeoroids than modeling before launch predicted, “the report concluded.

If it turns out that Webb has a higher risk of damage, NASA and Webb’s partners may consider minimizing the amount of time the telescope sees in directions where more micrometeoroids are flying through space, or pointing the telescope away during certain meteor showers.

For now, however, the telescope is ready to succeed.

“With revolutionary capabilities, the JWST has begun the first of many years of scientific discovery,” the report concluded.

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