Irreversible damage from space rocks won’t stop Webb telescope from exceeding expectations

Irreversible damage from space rocks won’t stop Webb telescope from exceeding expectations

Yes, a tiny particle of rock hit the Webb telescope. No, the mission is not about to be doomed.

You may have read misleading headlines pointing out that the James Webb Space Telescope – the most powerful observatory ever built – has suffered permanent damage. It’s an excerpt from a new 55-page report detailing the instrument’s excellent scientific performance over the past six months as engineers prepared and tested its unprecedented cosmic visualization capabilities.

The Webb Telescope, overall, is in very good condition. Here’s what you need to know about the state of the observatory that will revolutionize our understanding of the cosmos.

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What have scientists concluded about the condition of the Webb Telescope?

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

Basically they expect Webb exceed expectations. “Furthermore, in almost every area, JWST’s scientific performance is better than expected,” the Webb scientists wrote.

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

Why does Webb expect to surpass? Its mirrors are cleaner than necessary to achieve its noble scientific goals. Its guidance system, which locks on and tracks targets, is better than it needs to be. And its overall performance in visualizing objects clearly is better than the requirements.

And if that wasn’t enough, Webb’s scientists concluded he had enough finished fuel on board to help power the mission for 20 years. (The telescope used less propellant than expected to arrive at its outpost about 1 million miles from Earth.) NASA originally hoped the instrument would last five years, and the agency has d I was initially delighted to learn that it would operate with the correct thruster for over 10 years.

With the Webb Telescope at peak performance, astronomers plan to:

  • See 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 that ever formed,” Jean Creighton, astronomer and director of the Manfred Olson Planetarium at the University of Wisconsin-Milwaukee, told Mashable last year.

  • View the cosmos in infrared light, allowing us to see much more of the universe. Infrared has longer wavelengths than visible light, so light waves glide more efficiently through cosmic clouds; light does not collide with these dense particles as often and is not scattered by them. Ultimately, Webb’s infrared vision can penetrate places the legendary Hubble Space Telescope cannot.

  • Observe distant exoplanets: The Webb Telescope carries specialized equipment, called spectrometers, which will revolutionize our understanding of these distant worlds. The instruments can decipher which molecules (such as water, carbon dioxide and methane) exist in the atmospheres of distant exoplanets – whether gas giants or smaller rocky worlds. Webb will look at exoplanets in the Milky Way galaxy. Who knows what we’ll find?

How serious is the damage done to Webb?

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

In the six months that scientists prepared the $10 billion telescope for its highly anticipated scientific operations, researchers detected six micrometeoroid impacts. Indeed, they were expecting about one hit per month. “Inevitably, any spacecraft will encounter micrometeoroids,” the report notes. Of the six hits, five had negligible effects.

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

mirrors on the James Webb Space Telescope

The image on the right shows a bright area (bottom right of the mirror) where a micrometer hit the Webb telescope, ultimately changing the surface of the mirror.
Credit: NASA / ESA / ASC

“However, the effect was small at the full telescope because only a small portion of the telescope area was affected,” the Webb scientists wrote.

Also, after the strike, Webb engineers worked to make slight adjustments to the alignment of the mirror, which limited small imaging errors. (Such errors are to be expected because the telescope drifts quite a bit in space.) “Webb’s ability to sense and adjust mirror positions allows for partial correction of the impact outcome,” NASA previously noted. “By adjusting the position of the affected segment, engineers can undo some of the distortion.”

What risks do future impacts on the telescope pose?

Only time will tell if this impact was rare or if it could be more common than Webb’s scientists estimated.

“It is not yet clear whether the May 2022 hit on the C3 segment was a rare event (i.e. an unlucky early hit by a high kinetic energy micrometeoroid that statistically could not occur only once in several years), or whether the telescope might be more susceptible to damage from micrometeoroids than pre-launch modeling predicted,” the report concludes.

If Webb is found to pose a higher risk of damage, NASA and its Webb partners may consider minimizing the time the telescope scans in directions where there are more micrometeoroids flying through space, or point the telescope during some meteor showers.

For now, however, the telescope is poised for success.

“With groundbreaking capabilities, JWST has embarked on the first of many years of scientific discovery,” the report concludes.

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