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

Irreversible space rock damage will not prevent the Webb telescope from exceeding expectations
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Yes, a small rock particle hit the Webb telescope. No, the mission is almost certainly not a failure.

You may have read the confusing headlines The James Webb Space Telescope – the most powerful such observatory ever built – suffered some permanent damage. This is a cherry-picked bit A new 55-page report It describes the instrument’s outstanding scientific performance over the past six months as engineers developed and tested it unprecedented cosmic vision.

The Webb telescope is generally in excellent condition. Here’s what you need to know about the state of the observatory that will revolutionize our understanding of space.

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

NASA and its collaboration partners, the Canadian Space Agency and the European Space Agency, concluded that Webb – even after a fast-moving micrometeoroid (a small, often dust-sized rock particle) struck and caused a “significant irreparable change” in one of the telescope’s 18 golds. . – coated hexagonal mirrors — “capable of fully achieving the discoveries for which they were built.”

Most importantly, that’s what they expect from Webb exceed expectations. “Furthermore, almost across the board, JWST’s science performance is better than expected,” the Webb scientists said.

“JWST’s science performance is better than expected.”

Why is Webb expected to be a high achiever? Its mirrors are purer than required to achieve high scientific goals. His management system, locks onto and tracks targets, better than required. And his overall performance to see objects clearly better than the requirements.

If that wasn’t good enough news, Webb’s scientists concluded that it had limited enough fuel to power the mission. 20 years. (The telescope used less fuel than planned It reaches its outpost about 1 million miles from Earth.) Initially, NASA hoped the instrument would last five years, and the agency was initially pleased to learn that it would work. Adequate fuel for more than 10 years.

With the high performance of the Webb telescope, astronomers plan to:

  • Take a look at the stars and galaxies that formed 13 billion years ago, just a few hundred million years after the Big Bang. “We’re going to see the 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.

  • See space in infrared light, which allows us to see more of the universe. Infrared is longer wavelengths than visible light, so light waves are more efficiently swept through cosmic clouds; light does not collide with these densely packed particles as often and is not scattered. Finally, Webb’s infrared vision could penetrate places the legendary Hubble Space Telescope could not.

  • Take a look at distant exoplanets: Web telescope carries special equipment called spectrometers, will revolutionize our understanding of these distant worlds. Instruments can decipher what molecules (such as water, carbon dioxide, and methane) are present in the atmospheres of distant exoplanets—whether gas giants or small rocky worlds. Webb will look at exoplanets in the Milky Way galaxy. Who knows what we will find?

How bad is the damage to Webb?

As you read above, the overall telescope is in excellent condition.

During the six months scientists prepared the $10 billion telescope for the expected science operations, researchers detected six impacts from micrometeoroids. Indeed, they expected about one hit every month. “Any spacecraft will inevitably encounter micrometeoroids,” the report states. Five of the six hits had minor effects.

But the impact between May 22 and 24 was strong enough to cause a “significant irreversible shift” in one of Webb’s 18 hexagonal mirror segments (segment C3), as noted above. Fortunately, the observatory’s mirror, which collects faint light from extremely distant space, is quite large at 21 feet across. This means that most of the telescope is unaffected.

Mirrors on the James Webb Space Telescope

The image on the right shows the area of ​​light (bottom right of the mirror) where the micrometroid hits the Webb telescope and eventually changes the surface of the mirror.
Credit: NASA / ESA / CSA

“However, the effect at the full telescope level was small because only a small part of the telescope field was affected,” Webb’s scientists wrote.

Moreover, after the strike, Webb engineers tried to make small adjustments to the mirror alignment, which limited any minor imaging errors. (Because the telescope drifts slightly in space, such errors are to be expected.) “Webb’s ability to sense and adjust the mirror positions allows partial correction of the resulting effects,” NASA noted earlier. “By adjusting the position of the affected segment, engineers can cancel out some of the distortion.”

What risks could the telescope cause in the future?

Only time will tell if this effect is rare or more common than the Webb scientists guessed.

“It is not yet clear whether the May 2022 C3 segment impact was a rare event (that is, an unfortunate early impact by a high-kinetic-energy micrometeoroid that occurs statistically only once every few years) or whether the telescope is more sensitive. damage caused by micrometeoroids is greater than pre-launch modeling predicted,” the report concluded.

If it turns out that Webb’s risk of damage is higher, NASA and its Webb partners can shift the telescope’s time to areas where there are more micrometeoroids flying through space, or move the telescope away for a certain period of time. meteor showers.

For now, the telescope is poised to succeed.

“With revolutionary capabilities, JWST has launched the first of many scientific discoveries in many years,” the report concludes.

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