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NASA’s James Webb Space Telescope was damaged after being shattered by space rocks, images show

NASA's James Webb Space Telescope was damaged after being shattered by space rocks, images show
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Damage to the main mirror of the James Webb Telescope by a micrometeorite impact in May is worse than first thought, according to new images revealed in a new report.

A paper published on Tuesday the academic preprint server arxiv.org The detailed account of Webb’s performance during the telescope’s commissioning revealed that most micrometeorite impacts on Webb’s large mirror caused negligible damage, but an impact in mid-May even left permanent damage to the telescope.

“The impact of a single micrometeorite, which occurred between May 22 and 24, 2022 UT, exceeded the pre-launch expected damage for a single micrometeoroid, prompting further investigation and modeling by the JWST project,” the report states .

Unlike the Hubble Space Telescope, which encloses in a cylindrical housing the primary mirror that the telescope uses to collect light and focus light on scientific instruments, Webb’s segmented mirror is 6.5 meters in diameter, facing space exposed. But given Webb orbit Around Lagrange Point 2, or L2, a region of space about 1 million miles from Earth, scientists expected Webb would encounter potentially dangerous micrometeorites only about once a month.

During commissioning from late January through June, as ground controllers calibrated, aligned, and tested Webb’s mirrors and instruments, the primary mirror suffered a total of six micrometeorite impacts.

Of those hits, five did little damage, causing less than 1 nanometer of root-mean-square wavefront error (RMS), a technical way to describe how much Webb’s mirror distorts the starlight the mirror collects. Most of the distortions caused by those five punches can be corrected from within the mirror, as the 18 hexagonal segments that make up his face can be individually and finely adjusted.

But the sixth hit, hitting a mirror segment labeled C3, did more damage that can be fully corrected. This micrometeorite impact increased the segment’s wavefront error from 56 nanometers to 178 nanometers after correction by segment adjustment.

However, since each mirror segment is adjustable, the damage to the C3 segment could be compensated for and did not affect the overall resolution of Webb’s primary mirror, according to the report. The total wavefront error for the entire mirror increased by about 9 nanometers from the impact.

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

The report further notes that the Webb project team is considering measures to mitigate future micrometeorite impacts, such as: B. Limiting how long the telescope can be pointed in directions known to expose the mirror to a higher probability of micrometeorite impacts.

Maintaining the long-term health of the Webb telescope has Our and astronomers everywhere.

After more than 20 years and $10 billion in development, the space telescope was launched on Christmas Day on an Ariane 5 rocket. That launch was more precise than expected, saving Webb significantly the fuel it would have needed to correct its course after launch and almost doubling the observatory’s projected operational lifespan — as long as space rocks don’t interfere with its optics.

“Prior to launch, JWST was required to carry propellant for at least 10.5 years of mission life,” the report said. “Now that JWST is in orbit around L2, it is clear that the remaining fuel will last for more than 20 years of mission life.”

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