5 ms·

It's not over yet - the micro-meteor strikes so far have been at a FAR higher rate than expected, and unless they turn out to be a statistical outliers, the lif

by q1w2 4y ago

It's not over yet - the micro-meteor strikes so far have been at a FAR higher rate than expected, and unless they turn out to be a statistical outliers, the lifespan of JWST is drastically reduced below expectations. This could still turn out to be a big disappointment if it goes offline within the year. I wonder how hard it is to launch a shield to protect it.

bjtitus 4y ago
> if it goes offline within the year This would be a >95% reduction in lifespan. I'm really curious what source suggests anything close to such a colossal failure in the predicted meteoroid environment.
avalys 4y ago
The telescope has had the mirror deployed for 6 months and so far it has had a single micrometeroid strike that exceeded expectations, and did some minor damage to a single mirror segment. Even if this continues at roughly the same rate, the telescope will continue to function within the initial design specification for at least another year or two, and will be far from "offline within a year". You can't extrapolate anything from a single event. It could have just been bad luck. If another one happens this year - then it's worth some concern.
muppetman 4y ago
I'm interested in the "strikes higher than expected" all I can find online is the one big strike a couple of weeks ago. Is there details online about the number it's getting?
- pja 4y ago
  It had one micrometeoroid strike that was larger than expected. This might mean the rate of strikes will be much larger than predicted, or it might be that we were just unlucky. We'll know more in a few months.
- widerporst 4y ago
  As of yet, there was only this one big strike that is a real problem. The frequency of micrometeoroids of this size and energy was predicted to be fairly low, so it isn't certain yet if this was extremely bad luck or if these events are more frequent than anticipated (which would be very bad news). The JWST performance report[1] says on page 18/19: "It is not yet clear whether the May 2022 hit to segment C3 was a rare event (i.e. an unlucky early strike by a high kinetic energy micrometeoroid that statistically might occur only once in several years), or whether the telescope may be more susceptible to damage by micrometeoroids than pre-launch modeling predicted." [1]: https://www.stsci.edu/files/live/sites/www/files/home/jwst/documentation/_documents/jwst-science-performance-report.pdf https://www.stsci.edu/files/live/sites/www/files/home/jwst/d...
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thombat 4y ago
Problem is, you don't want to protect it from photons...

by q1w2 4y ago

bjtitus 4y ago

> if it goes offline within the year This would be a >95% reduction in lifespan. I'm really curious what source suggests anything close to such a colossal failure in the predicted meteoroid environment.

avalys 4y ago

The telescope has had the mirror deployed for 6 months and so far it has had a single micrometeroid strike that exceeded expectations, and did some minor damage to a single mirror segment. Even if this continues at roughly the same rate, the telescope will continue to function within the initial design specification for at least another year or two, and will be far from "offline within a year". You can't extrapolate anything from a single event. It could have just been bad luck. If another one happens this year - then it's worth some concern.

muppetman 4y ago

I'm interested in the "strikes higher than expected" all I can find online is the one big strike a couple of weeks ago. Is there details online about the number it's getting?

pja 4y ago
It had one micrometeoroid strike that was larger than expected. This might mean the rate of strikes will be much larger than predicted, or it might be that we were just unlucky. We'll know more in a few months.
widerporst 4y ago
As of yet, there was only this one big strike that is a real problem. The frequency of micrometeoroids of this size and energy was predicted to be fairly low, so it isn't certain yet if this was extremely bad luck or if these events are more frequent than anticipated (which would be very bad news). The JWST performance report[1] says on page 18/19: "It is not yet clear whether the May 2022 hit to segment C3 was a rare event (i.e. an unlucky early strike by a high kinetic energy micrometeoroid that statistically might occur only once in several years), or whether the telescope may be more susceptible to damage by micrometeoroids than pre-launch modeling predicted." [1]: https://www.stsci.edu/files/live/sites/www/files/home/jwst/documentation/_documents/jwst-science-performance-report.pdf https://www.stsci.edu/files/live/sites/www/files/home/jwst/d...

deleted 4y ago

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thombat 4y ago

Problem is, you don't want to protect it from photons...