To everyone saying "what's the big deal, it sees more vibration on launch":
It sounds to me like this is more of an unintended shock event (see zeeb's response below) that caused an oscillation at the natural frequency ("vibration") but they tortuously avoided using the word "shock".
This would result in a given shock response spectrum [1], which effectively can amplify the input if it hits any part's natural frequency - e.g. a 1G input shock could become a 5G response somewhere in the satellite. I assume this wasn't accounted for in design so they'll determine if this could have damaged any onboard systems.
Launch vibration has a well known Power Spectral Density [2] which effectively says how much energy is being input at every frequency. If they design the system so no parts have a natural frequency at a high-energy peak it's safe.
Shock and vibration are closely related, but very different in practice. It's all about natural frequencies and what frequencies the energy is being input at.
RUAG makes most of the "payload adapters" that integrate the satellite onto the top of a rocket. Based on the size of JWST they're probably using a 1666 model payload adapter.
RUAG's clamp-bands and separation system have a very well characterized Shock Response Spectrum [0, pg. 4], which would have been accounted for in the design of JWST. But the spacecraft and satellite usually separate after the initial shock of the explosive bolt and clamp-band de-tensioning, so they may need to investigate any coupling or recontact of the clamp-band.
If we're lucky they had some accelerometers running during integration and can review actual response data.
Right, in design shock and vibration are basically 2 separately requirements, analyzed and tested separately. Sometimes by analysis it is shown that vibration test levels "cover" the shock requirement, but a spacecraft that is the first of its type, and with many mechanisms is likely to undergo discrete shock testing.
Minor addition to your reply, design typically avoids similar natural frequencies to the launcher, but the design needs to be compatible with the loads resulting from vibration as
It sounds like the clamp band was accidentally released just after installation, thankfully in a position that didn't drop the spacecraft somehow. The input shock is more like 1000G for these things, usually the largest source of shock for a spacecraft. Of course, it's designed to be released by the same mechanism, although it would not be designed to be released an unlimited number of times. I would guess they already know the components which are critical for shock, and will inspect and/or function test those before proceeding. Since it was an unplanned event, even documenting that it happened and getting everyone to agree to proceed based on the spacecraft having been designed for that input shock, takes at least a few days.
It does not sound like a larger than design shock was somehow applied and they have to check everything at spacecraft level analysis. That would take at least several weeks.
Is the JWST in a state where they can open it up and inspect? Or are they just going to run simulations to see if the shock/vibration would cause any anomalies?
> Let's be honest, words like "incident," "sudden," and "vibration" are not the kinds of expressions one wants to hear about the handling of a delicate and virtually irreplaceable instrument like the Webb telescope.
This reminded me of the terms the kerbal space program community use like "Rapid Unplanned Disassembly (RUD)" and "Lithobraking" (crashing into the ground thus "braking" and often breaking, an usually unwanted alternative to aerobraking).
I wouldn't be surprised to see the KSP community use Sudden Vibration Incident as a euphemism for what happens when you exit time-warp and sometimes the whole spaceship turns into a vibrating jelly.
Its easy to say "Just build two of them" or to say the telescope shouldn't have so many single points of failure.
To that I say that a single copy is the only reasonable option. JWT is essentially a prototype and a product in one.
The first to employ such a complex radiation shield,
The first to have berrylium mirrors (AFAIK),
The first to orbit L2.
A copy would inherit any unknown problems with the first telescope, which is especially bad if you've read how many times the JWT has run overbudget and ran into issues. You're better off launching the prototype product to learn what will go wrong and go from there.
The lack of doubles in space shows how exiting the field is because I'd rather have novel prototypes than another hubble.
Without a complete and honest accounting of the risk profile, which is something NASA and its contractors have historically not been great at, it's hard to say whether test/backup hardware would have been warranted.
IMO "build two, launch one and see what happens" was absolutely not the right approach here. But the goal of the program is to get a functional JWST instrument into position, and if there's any relatively (wrt. the entire program) cheap way they could have substantially de-risked that outcome—by tooling up for a possible second production run, flying a "dumb" article to test the deployment procedure in situ, or whatever else—it should have been seriously considered.
Frankly, this sort of judgment is something I don't trust NASA to get right in practice, through no major fault of their own. Congress runs NASA like they run the rest of the country: setting them up to fail, blaming them when they inevitably do, withholding realistic funding for congressionally mandated programs while simultaneously helping their military-industrial cronies wring out every last dollar. The only way to get anything at this scale done is to lowball up front and beg for more money later.
Good point. But doing two concurrenct desing would allow as backups for failures not in the telescope itself. For things like lauch, assembly, handling, etc.
If everything goes as planned, having two observatories sure would be appreciated by the scientific community.
Also, I assume, most the costs are associated with the project and setup of fabrication.
"Technicians were preparing to attach Webb to the launch vehicle adapter, which is used to integrate the observatory with the upper stage of the Ariane 5 rocket," NASA said in a blog post. "A sudden, unplanned release of a clamp band—which secures Webb to the launch vehicle adapter—caused a vibration throughout the observatory."
Engineers at heart wouldn't let a single point of failure in in the design of it to let a pin drop unexpectedly. Is the vehicle insured for a do-over should it fail to launch unspectacularly and land in the water?
Does anyone know how much of the price tag for JWST is manufacturing, as opposed to research/design/development costs? I would expect the actual manufacturing is a very small fraction, so I don't understand why they haven't built two of them - would seem to be good insurance for just this sort of mishap. And if you do find a problem when the first one is commissioned at the inaccessible L2 point, you at least have some chance to correct it on the second one. Best case is you get two for nearly the price of one.
The root problem with JWST was not being able to get the money in the first place. That led to budgeting shenanigans responsible for much of the project delay. The single telescope came within a whisker of being scrapped by Congress.
If you gave projects like Webb the kind of budget that now gets eaten by human space flight, you could have telescopes filling half the sky. But NASA has to work within the really severe funding constraints imposed by the white elephant that is ISS.
I don't think there's a meaningful distinction between "manufacturing" and other development activities in this case. This sort of thing, an effort to build a single example of a device using a mountain of new technology, just can't follow the process of design the whole thing, then manufacture it, then we're done. Kind of like waterfall vs agile software development. They're probably constantly fabricating and testing subsystems in various ways, iterating on manufacturing technique to get quality good enough, making changes in other related subsystems as a result of things they found to be impractical with the first, making sure subsystems actually integrate with each other as expected, etc.
They may not have the labor to build two of them. It's exceptionally difficult to put together the team necessary to build one of them.
The US isn't a serious nation any longer. The US is increasingly becoming a clown show. The response you'd get if you suggested to consider building two of them - for the reasons you mention - is that people would freak out (two boondoggles, $20 billion in cost, decades of time; that would be the flailing, screeching response).
I think the difference is whether the vibration is expected.
Vibrations from being launched are probably accounted for and tested numerous times, while an unintended vibration caused by a "sudden, unplanned release of a clamp band" could cause unforeseen damages to the instrument.
The statement does not actually say anything about the magnitude of the vibrations during this incident, let alone how they compare to those expected during launch.
Boeing thought their last launch delay was just going to take a small amount of time too. Then, as they dug into it, they basically put it on indefinite hold when they realized they had no idea on what to do about the issue causing the dealy.
Of course they will come out and say "just a short delay" immediately, but who knows what the actual delay gets to when they really start looking at it. Besides, how can they really know that it is okay without taking it down and putting it through all of the motions? A bent arm in a manner not visible while folded in launch config but prevents it from unfolding after launch is a very dumb reason to not have this thing work.
Maybe Elon is right, and instead of spending tens of billions of dollars and decades on one bulletproof piece of jewelry, maybe we should just launch 20 cheaply built ones with less redundancy and hope a couple make it through.
Think monolith mainframe versus cluster of commodity hardware.
There was a great article about this recently on HN, about how Spaceship will change everything with it's extremely cheap price per kilo and how NASA is not ready for it.
This is not Elon’s idea, there was much clamoring in the scientific community to spread the research dollars instead of having one flagship suck up all the funding. It’s a big gamble to be able to see what JWST is designed to see, no number of smaller projects would match it, whether it was the best use of our taxdollars remains to be seen
> Maybe Elon is right, and instead of spending tens of billions of dollars and decades on one bulletproof piece of jewelry
Musk is pretty much socially incompetent, proven so many times. On this topic he discounts the fact that the type of individuals needed to do this job have plenty of offers and nobody wants to work on something which will blow up and has very low odds of making it. Especially smart people who bathe in the concept of opportuinity cost with regards to their time and carrer.
Would it be possible to build an autonomously-assembling modular space telescope, launched piecemeal, with each piece rendezvousing at L2 and bolting on to the previous pieces? The idea being to lower the launch stakes.
"NASA's follow-on instrument to the wildly successful Hubble Space Telescope was originally due to launch about a decade ago"
I don't think anything else could better express just how bad the government is at deploying capital than the sentence above. Say what you will above SpaceX, but what they've been able to achieve in the time that this launch has been DELAYED is astounding.
We should be launching a new JWST every year. And we could, for a tiny fraction of the cost of a single large DOD project. Hopefully Starship will make these once-in-a-generation level missions more commonplace, so we're not losing our minds over every tiny thing that can go wrong with this thing.
Are you implying that yearly launches would reduce cost through economies of scale or something? Or just that JWST costs less than the F-35 program?
While having a Starship sized fairing to put JWST in for launch would probably reduce some packaging complexity, I'm not sure the launch vehicle is the major source of cost in this case.
Maybe, just maybe, if we stopped building telescopes like fragile porcelain dolls with glass heads that can't take a scratch and started building them like tanks that can take a beating..
What is the plan for these sorts of highly-expensive, super-delicate instruments in an environment where Russia (or other spacefaring nations) just blow things up leaving huge clouds of debris that would destroy it in seconds?
Does the JWST just operate at a different level of orbit or something?
[+] [-] scrooched_moose|4 years ago|reply
It sounds to me like this is more of an unintended shock event (see zeeb's response below) that caused an oscillation at the natural frequency ("vibration") but they tortuously avoided using the word "shock".
This would result in a given shock response spectrum [1], which effectively can amplify the input if it hits any part's natural frequency - e.g. a 1G input shock could become a 5G response somewhere in the satellite. I assume this wasn't accounted for in design so they'll determine if this could have damaged any onboard systems.
Launch vibration has a well known Power Spectral Density [2] which effectively says how much energy is being input at every frequency. If they design the system so no parts have a natural frequency at a high-energy peak it's safe.
Shock and vibration are closely related, but very different in practice. It's all about natural frequencies and what frequencies the energy is being input at.
1) https://en.m.wikipedia.org/wiki/Shock_response_spectrum
2) https://vru.vibrationresearch.com/lesson/what-is-the-psd/
[+] [-] zeeb|4 years ago|reply
RUAG's clamp-bands and separation system have a very well characterized Shock Response Spectrum [0, pg. 4], which would have been accounted for in the design of JWST. But the spacecraft and satellite usually separate after the initial shock of the explosive bolt and clamp-band de-tensioning, so they may need to investigate any coupling or recontact of the clamp-band.
If we're lucky they had some accelerometers running during integration and can review actual response data.
0) https://www.ruag.com/system/files/media_document/2019-03/PLE...
[+] [-] johnwalkr|4 years ago|reply
Minor addition to your reply, design typically avoids similar natural frequencies to the launcher, but the design needs to be compatible with the loads resulting from vibration as
It sounds like the clamp band was accidentally released just after installation, thankfully in a position that didn't drop the spacecraft somehow. The input shock is more like 1000G for these things, usually the largest source of shock for a spacecraft. Of course, it's designed to be released by the same mechanism, although it would not be designed to be released an unlimited number of times. I would guess they already know the components which are critical for shock, and will inspect and/or function test those before proceeding. Since it was an unplanned event, even documenting that it happened and getting everyone to agree to proceed based on the spacecraft having been designed for that input shock, takes at least a few days.
It does not sound like a larger than design shock was somehow applied and they have to check everything at spacecraft level analysis. That would take at least several weeks.
[+] [-] sudhirj|4 years ago|reply
[+] [-] laydn|4 years ago|reply
[+] [-] SahAssar|4 years ago|reply
This reminded me of the terms the kerbal space program community use like "Rapid Unplanned Disassembly (RUD)" and "Lithobraking" (crashing into the ground thus "braking" and often breaking, an usually unwanted alternative to aerobraking).
I wouldn't be surprised to see the KSP community use Sudden Vibration Incident as a euphemism for what happens when you exit time-warp and sometimes the whole spaceship turns into a vibrating jelly.
[+] [-] Kye|4 years ago|reply
[+] [-] Out_of_Characte|4 years ago|reply
To that I say that a single copy is the only reasonable option. JWT is essentially a prototype and a product in one. The first to employ such a complex radiation shield, The first to have berrylium mirrors (AFAIK), The first to orbit L2.
A copy would inherit any unknown problems with the first telescope, which is especially bad if you've read how many times the JWT has run overbudget and ran into issues. You're better off launching the prototype product to learn what will go wrong and go from there.
The lack of doubles in space shows how exiting the field is because I'd rather have novel prototypes than another hubble.
[+] [-] jobigoud|4 years ago|reply
There are some doubles though. Voyager 1 & 2, Spirit and Opportunity…
[+] [-] caconym_|4 years ago|reply
IMO "build two, launch one and see what happens" was absolutely not the right approach here. But the goal of the program is to get a functional JWST instrument into position, and if there's any relatively (wrt. the entire program) cheap way they could have substantially de-risked that outcome—by tooling up for a possible second production run, flying a "dumb" article to test the deployment procedure in situ, or whatever else—it should have been seriously considered.
Frankly, this sort of judgment is something I don't trust NASA to get right in practice, through no major fault of their own. Congress runs NASA like they run the rest of the country: setting them up to fail, blaming them when they inevitably do, withholding realistic funding for congressionally mandated programs while simultaneously helping their military-industrial cronies wring out every last dollar. The only way to get anything at this scale done is to lowball up front and beg for more money later.
[+] [-] boibombeiro|4 years ago|reply
If everything goes as planned, having two observatories sure would be appreciated by the scientific community.
Also, I assume, most the costs are associated with the project and setup of fabrication.
[+] [-] unknown|4 years ago|reply
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[+] [-] yosito|4 years ago|reply
[+] [-] mcast|4 years ago|reply
[+] [-] thuccess129|4 years ago|reply
[+] [-] netcraft|4 years ago|reply
[+] [-] yummybear|4 years ago|reply
[+] [-] mhandley|4 years ago|reply
[+] [-] drybjed|4 years ago|reply
-- S. R. Hadden, Contact (https://www.youtube.com/watch?v=Et4sMJP9FmM)
[+] [-] idlewords|4 years ago|reply
If you gave projects like Webb the kind of budget that now gets eaten by human space flight, you could have telescopes filling half the sky. But NASA has to work within the really severe funding constraints imposed by the white elephant that is ISS.
[+] [-] ufmace|4 years ago|reply
[+] [-] thuccess129|4 years ago|reply
[+] [-] adventured|4 years ago|reply
The US isn't a serious nation any longer. The US is increasingly becoming a clown show. The response you'd get if you suggested to consider building two of them - for the reasons you mention - is that people would freak out (two boondoggles, $20 billion in cost, decades of time; that would be the flailing, screeching response).
[+] [-] deodorel|4 years ago|reply
[+] [-] TwoFerMaggie|4 years ago|reply
[+] [-] NikolaeVarius|4 years ago|reply
It is not rated for being dropped.
[+] [-] unknown|4 years ago|reply
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[+] [-] kobalsky|4 years ago|reply
[+] [-] mannykannot|4 years ago|reply
[+] [-] xupybd|4 years ago|reply
[+] [-] dylan604|4 years ago|reply
Of course they will come out and say "just a short delay" immediately, but who knows what the actual delay gets to when they really start looking at it. Besides, how can they really know that it is okay without taking it down and putting it through all of the motions? A bent arm in a manner not visible while folded in launch config but prevents it from unfolding after launch is a very dumb reason to not have this thing work.
[+] [-] protomolecule|4 years ago|reply
[+] [-] arbitrage|4 years ago|reply
[+] [-] 323|4 years ago|reply
Think monolith mainframe versus cluster of commodity hardware.
There was a great article about this recently on HN, about how Spaceship will change everything with it's extremely cheap price per kilo and how NASA is not ready for it.
[+] [-] jazzyjackson|4 years ago|reply
[+] [-] SahAssar|4 years ago|reply
Like if I gave you 20 shitty 360p cameras to shoot a movie would it look as good as if I gave you one Arri Alexa?
[+] [-] GDC7|4 years ago|reply
Musk is pretty much socially incompetent, proven so many times. On this topic he discounts the fact that the type of individuals needed to do this job have plenty of offers and nobody wants to work on something which will blow up and has very low odds of making it. Especially smart people who bathe in the concept of opportuinity cost with regards to their time and carrer.
[+] [-] unknown|4 years ago|reply
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[+] [-] thewakalix|4 years ago|reply
[+] [-] jl6|4 years ago|reply
[+] [-] 0xffff2|4 years ago|reply
[+] [-] ryanSrich|4 years ago|reply
I don't think anything else could better express just how bad the government is at deploying capital than the sentence above. Say what you will above SpaceX, but what they've been able to achieve in the time that this launch has been DELAYED is astounding.
[+] [-] ramesh31|4 years ago|reply
[+] [-] FourHand451|4 years ago|reply
While having a Starship sized fairing to put JWST in for launch would probably reduce some packaging complexity, I'm not sure the launch vehicle is the major source of cost in this case.
[+] [-] bguebert|4 years ago|reply
[+] [-] rafaelturk|4 years ago|reply
[+] [-] joshuahedlund|4 years ago|reply
Still under one month? At least the slope is still less than one[1]
[1]https://xkcd.com/2014/
[+] [-] jacknews|4 years ago|reply
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[+] [-] HenryKissinger|4 years ago|reply
[+] [-] nkcmr|4 years ago|reply
Does the JWST just operate at a different level of orbit or something?
(edit: don't just single out Russia)