<p>This would not be possible. The JWST doesn't have downtime. It is always observing, or moving into position to observe (which requires it to be observing guide stars etc).</p>
<p>A shield that would work would be too heavy. Meteorites can come from any direction. You would completely surround the telescope and completely block out light.</p>
<p>Meteorites are expected. The telescope is not damaged. The telescope is designed to be hit repeatedly during its deployment. Your language is unreasonably dramatic. You should say &quot;A meteorite has hit the telescope and has had a marginally detectable effect&quot;, which is a lot different from &quot;done irreversible damage&quot;.</p>

CC BY-SA 4.0
2022-07-28T14:15:21.813Z
You don't want to unduly minimize the impact either.  If JWST continued to receive strikes at the rate implied by the first strike, it's operational lifetime would be reduced to less than its design parameters.
antlersoft
CC BY-SA 4.0
2022-07-28T14:59:47.120Z
Do all Solar Systems have meteors, comets etc. , rocks left over from the formation of a Solar System, or is this unknown ? Also does interstellar Space have these  damage causing meteorites as well ? Sorry if this is going away from the original topic.
Peter U
CC BY-SA 4.0
2022-07-28T15:04:33.347Z
@James K but the meteorite did cause noticeable damage to the Space Telescope which cannot be fixed .  It may be minor but if it becomes a frequent event ,then yes it will be serious.
Peter U
CC BY-SA 4.0
2022-07-28T15:04:48.207Z
Do all Solar Systems have meteors, comets etc. , rocks left over from the formation of a Solar System -  Yes (as far as we know) . interstellar Space have these damage causing meteorites  Yes, but fewer.   Feel free to ask a new question!
James K
CC BY-SA 4.0
2022-07-28T15:08:58.910Z
" cause noticeable damage to the Space Telescope"  not really.  This is what insurers call normal wear and tear.  This kind of event can happen pretty regularly without degrading the science.  The coolant would run out long long before the accumulation of this kind of impact would cause functional damage. (ie damage that affects the ability of the telescope to do science)
James K
CC BY-SA 4.0
2022-07-28T15:15:10.307Z
@PeterU Yes, we expect typical stellar systems to contain a *lot* of small material. OTOH, space is big, and there's generally a large distance between the bigger rocks. I have some details about this regarding our Solar system here: https://astronomy.stackexchange.com/a/49425/16685 & https://astronomy.stackexchange.com/a/46928/16685
PM 2Ring
CC BY-SA 4.0
2022-07-31T15:24:24.827Z
@JamesK MIRI's cryocooler uses a reversible process, the coolant won't ever run out. The JWST is supposed to last until its station-keeping propellant runs out.
Zac67
CC BY-SA 4.0
2022-08-01T22:12:29.957Z
“ but the meteorite did cause noticeable damage to the Space Telescope which cannot be fixed .” Wrong. The existing alignment actuators on each segment are sufficient that the figure error is only relevant locally. i. e., it was warped out. That segment has no science-level effect on the overall telescope PSF. Do not tell us how to do our jobs.
caInstrument
CC BY-SA 4.0
2022-07-28T06:09:15.893Z
2022-07-28T06:43:30.660Z
2022-07-28T06:43:30.660Z
James K
<p>Unfortunately a meteorite has already hit the telescope and caused irreversible damage to it. I was wondering if they could have provided a cover or shield, to protect it when it is not observing. Or does it need to be observing constantly and so cannot be covered to protect it from such damage causing collisions?</p>

CC BY-SA 4.0
2022-07-27T21:59:35.717Z
Related: https://astronomy.stackexchange.com/q/49532/16685
PM 2Ring
CC BY-SA 4.0
2022-07-27T22:07:07.627Z
Sounds complicated. And heavy. And moving it would chew up energy, and generate heat. What kind of shield do you recommend that will stop rocks travelling at upto 40 km/s?
PM 2Ring
CC BY-SA 4.0
2022-07-27T23:34:04.233Z
I suspect there probably isn't much downtime for the JWST;  They probably have more good proposals for observing time coming in than there is _actual time_, by an order of magnitude or two.
notovny
CC BY-SA 4.0
2022-07-28T14:00:03.287Z
In addition, with or without a magic shield,  momentum conservation leads to a need to realign.
Carl Witthoft
CC BY-SA 4.0
2022-07-28T15:08:42.033Z
@PM 2Ring I agree and also I wonder how they plan on dealing with this hazard, on any future manned space travel to Mars ?
Peter U
CC BY-SA 4.0
2022-07-28T15:21:54.577Z
@PeterU Question about space vehicles are on-topic on our sister site, https://space.stackexchange.com/questions/tagged/shielding The JWST is on-topic here because it's a telescope.
PM 2Ring
<james-webb-space-telescope><meteorite>
Could the James Webb Space Telescope be protected from meteorites?
Peter U
# Could the James Webb Space Telescope be protected from meteorites?

(Asked by: username_0 on 2022-07-27)

Unfortunately a meteorite has already hit the telescope and caused irreversible damage to it. I was wondering if they could have provided a cover or shield, to protect it when it is not observing. Or does it need to be observing constantly and so cannot be covered to protect it from such damage causing collisions?

**Tags:** james-webb-space-telescope, meteorite

> **Comments:**
> **username_1**: Related: https://astronomy.stackexchange.com/q/49532/16685  
> **username_1**: Sounds complicated. And heavy. And moving it would chew up energy, and generate heat. What kind of shield do you recommend that will stop rocks travelling at upto 40 km/s?  
> **username_2**: I suspect there probably isn't much downtime for the JWST;  They probably have more good proposals for observing time coming in than there is _actual time_, by an order of magnitude or two.  
> **username_3**: In addition, with or without a magic shield,  momentum conservation leads to a need to realign.  
> **username_0**: @username_1 I agree and also I wonder how they plan on dealing with this hazard, on any future manned space travel to Mars ?  
> **username_1**: @username_0 Question about space vehicles are on-topic on our sister site, https://space.stackexchange.com/questions/tagged/shielding The JWST is on-topic here because it's a telescope.  

---

## 1 answers

### Answer by username_4 on 2022-07-28. Score: 5

This would not be possible. The JWST doesn't have downtime. It is always observing, or moving into position to observe (which requires it to be observing guide stars etc).

A shield that would work would be too heavy. Meteorites can come from any direction. You would completely surround the telescope and completely block out light.

Meteorites are expected. The telescope is not damaged. The telescope is designed to be hit repeatedly during its deployment. Your language is unreasonably dramatic. You should say "A meteorite has hit the telescope and has had a marginally detectable effect", which is a lot different from "done irreversible damage".

> **Comments:**
> **username_5**: You don't want to unduly minimize the impact either.  If JWST continued to receive strikes at the rate implied by the first strike, it's operational lifetime would be reduced to less than its design parameters.  
> **username_0**: Do all Solar Systems have meteors, comets etc. , rocks left over from the formation of a Solar System, or is this unknown ? Also does interstellar Space have these  damage causing meteorites as well ? Sorry if this is going away from the original topic.  
> **username_0**: @username_4 but the meteorite did cause noticeable damage to the Space Telescope which cannot be fixed .  It may be minor but if it becomes a frequent event ,then yes it will be serious.  
> **username_4**: Do all Solar Systems have meteors, comets etc. , rocks left over from the formation of a Solar System -  Yes (as far as we know) . interstellar Space have these damage causing meteorites  Yes, but fewer.   Feel free to ask a new question!  
> **username_4**: " cause noticeable damage to the Space Telescope"  not really.  This is what insurers call normal wear and tear.  This kind of event can happen pretty regularly without degrading the science.  The coolant would run out long long before the accumulation of this kind of impact would cause functional damage. (ie damage that affects the ability of the telescope to do science)  
> **username_1**: @username_0 Yes, we expect typical stellar systems to contain a *lot* of small material. OTOH, space is big, and there's generally a large distance between the bigger rocks. I have some details about this regarding our Solar system here: https://astronomy.stackexchange.com/a/49425/16685 & https://astronomy.stackexchange.com/a/46928/16685  
> **username_6**: @username_4 MIRI's cryocooler uses a reversible process, the coolant won't ever run out. The JWST is supposed to last until its station-keeping propellant runs out.  
> **username_7**: “ but the meteorite did cause noticeable damage to the Space Telescope which cannot be fixed .” Wrong. The existing alignment actuators on each segment are sufficient that the figure error is only relevant locally. i. e., it was warped out. That segment has no science-level effect on the overall telescope PSF. Do not tell us how to do our jobs.  

---

