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Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @03:27PM (#29855830)
Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?
Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @03:46PM (#29856027)
Because it's a wrong assumption. Significant cost come from the assembly and testing of all the components itself, that you would have to redo entirely.

Also if you were to build just 2 or 3 of them, you can't expect any economy of scale.

On top of that, the operational cost of JWST is expected to be around 1B$ for it's lifetime, you could expect that to be similar for every single replica you have.

And finally, you can only put one per rocket, and just the rocket is about 200M$ dollar, and you need to add all the cost of shipping the telescope to Guyana, that's not cheap.

So overall, while a second replica would not cost you another 10B, it would probably cost in the order of 3-5B$, that's a lot of billions for a telescope with exactly identical capabilities to another one. It would still be useful, as astronomers are going to have to compete for time on the JWST and not everyone will be served, but the benefits of a second one would be marginal compared to the benefits of the first one. So the price/benefit ratio might actually be worse on a new copy.

Meanwhile, there is a myriad of other very cool NASA projects that would greatly benefit from 3-5B$ instead and do things that we haven't done so far.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @04:16PM (#29856378)
Assuming your figures are correct, you'll get double the data for another 30% cost.

If you wait a month before launching #2, if problems appear in #1 (like the telescope mirror was ground improperly) it can be fixed in #2.

The operational cost will not double. The same ground facility, equipment, and staff can manage both.

If you're buying two identical launches, you can get a quantity discount.

> the benefits of a second one would be marginal compared to the benefits of the first one

And yet I read many glowing accounts about how much extra value came from extending the Hubble's lifetime.

I do have some experience with this. I worked for 3 years on the design of the 757. Thousands of engineers spending maybe 5 years on it. None of that has to be repeated. In a machine shop, most of the cost is in the setup. Making two adds little cost. I had a job assembling electronics to help pay for college. The first board would take 2 hours to build. The next one, half that. The fourth, 20 minutes.

I'm sure there's plenty of software on board that machine. On HN we all know how expensive making software is. Making a copy costs nothing.

Re:James Webb is fully deployed by mlyle on Saturday January 08, 2022 @05:01PM (#29856825)
> Assuming your figures are correct, you'll get double the data for another 30% cost.

I think 30% is probably a reasonable guess, based on past programs where people have flown 2. You get to reuse design and some fixturing. You get to share some operational costs. But you're not at unit counts where you benefit from mass production techniques and a whole lot of verification and qualification work are still effectively one-offs for each one.

(You save a whole bunch of costs related to making a repeatable program that can turn out hundreds of an item, but more has to be validated/verified for each unit).

The thing is-- what's the marginal value of the additional data (and of the higher priority data arriving earlier)? Would you rather have 2 James Webbs for $13B, or 1 James Webb & some other $3B mission?

(Or, at the outset/original decision making: do you aim for 2 somewhat simpler telescopes or 1 really awesome telescope with the block of money you're given?)

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @08:37PM (#29858887)
Another poster here remarked that spares would be made. That would indicate the cost of doing so isn't that remarkable.
Re:James Webb is fully deployed by mlyle on Saturday January 08, 2022 @11:51PM (#29860259)
Lots of engineering models. Some spare parts for parts of assemblies.

Not a lot of complete, flight-capable assemblies.

I'm actually teaching a bunch of high school students to make a cubesat right now, and we are going through costing of:

* Prototypes -> protoflight -> flight, no engineering model

* "Flatsat" electronic engineering model, prototypes -> protoflight -> flight

* Prototypes -> qualification article -> flight article, + "flatsat"

* Prototypes -> qualification article -> flight article + ground engineering model

There's a whole lot of derisk that happens as you go down that list, but the cost and labor increase (the latter is "free" for us but also limited) is substantial.

Re:James Webb is fully deployed by BobbyJo on Saturday January 08, 2022 @04:33PM (#29856537)
Double the data may not be worth 30-50% more money to NASA. Going from no data of type X to 1 data of type X is worth a lot more than going from 1 to 2, and so the leap from 1 to 2 might just not be worth it, even if it is 50% cheaper than the leap from 0 to 1.
Re:James Webb is fully deployed by bumby on Saturday January 08, 2022 @04:44PM (#29856649)
>Making two adds little cost.

I think you are overextending your experience in a production environment here.

I’ve worked in both, and the type of builds in these aerospace applications still have huge costs in subsequent runs. Hell, even rebuilding an existing component can be prohibitively expensive.

Much of the GSE was likely existing so that’s probably a non-issue.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:03PM (#29856854)
> huge costs in subsequent runs

Often that's because they have to rebuild and reset the tooling. Within the run, though, the incremental cost should be minimal.

The huge costs may be huge, but not huge compared to the cost of the prototype.

Re:James Webb is fully deployed by bumby on Saturday January 08, 2022 @05:39PM (#29857244)
IMO your logic fits with large production runs.

In space applications costs can be exaggerated compared to actual production environments because the risks aren’t mitigated by something like the FAA, meaning they are often mitigated by some downstream process. Besides, a lot of the the designs already include critical spares, so there’s more than a single run, even in a one-off design

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:49PM (#29857366)
So build a copy out of the spares! If they're there, they're already paid for.
Re:James Webb is fully deployed by bumby on Saturday January 08, 2022 @06:08PM (#29857565)
Not every part meets the criteria to be a "critical" spare. You don't have a complete set of spares for every component.
Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @08:39PM (#29858902)
Are you suggesting that spares are only produced for the cheap parts?
Re:James Webb is fully deployed by bumby on Sunday January 09, 2022 @09:21AM (#29863428)
No. Only for the parts deemed critical.

An example may be a part with a long lead time and no redundancy. If it is found defective during testing, they need a replacement right away and don’t want the schedule to slip while it gets fabricated

Re:James Webb is fully deployed by kragen on Saturday January 08, 2022 @06:16PM (#29857649)
A lot of times when you make one of something, there's stuff you would make tooling for if you were going to do more than one, but which instead you do by hand. Sometimes this is even true in software, but not very often, because the advantages of being able to recompile something from source code are so huge.
Re:James Webb is fully deployed by WalterBright on Sunday January 09, 2022 @03:31AM (#29861459)
Even when doing things by hand, making a duplicate alongside the original is not much more time. That happens to me every time I do something by hand.
Re:James Webb is fully deployed by kragen on Sunday January 09, 2022 @03:13PM (#29866902)
This is true for things like motor mounts and pipe flanges, but not for things like optical surfaces and lathe ways. Even in cases where it is true, if you didn't make the duplicate alongside the original, you have to do the setup again to make a duplicate.
Re:James Webb is fully deployed by WalterBright on Monday January 10, 2022 @03:10PM (#29881361)
Yes, make it alongside the original. I've been saying that all along.
Re:James Webb is fully deployed by bumby on Monday January 10, 2022 @05:58PM (#29884193)
I think your mindset is stuck in thinking about this as an airplane production environment because that was your experience. And your points make sense in that type of environment. But research aerospace in which JWST operates is a very different scale, operating much more at the margins where the tech is less well understood and takes much longer to develop. Investing billions for redundancy on an unproven system is a big risk (besides the fact that it would likely be designed differently - and better - if started today).

The sunk cost fallacy already drives a lot of these projects...imagine how much worse it would be (and how many other, competing projects wouldn't get funded) if the costs were higher.

Re:James Webb is fully deployed by kragen on Monday January 10, 2022 @03:56PM (#29882288)
Doesn't help with telescope mirrors, as you likely know from experience.
Re:James Webb is fully deployed by bumby on Sunday January 09, 2022 @09:25AM (#29863465)
I think the error in your assumption comes, in part, that there’s is tooling set u for mass production of each part.

A lot of parts are hand-fabricated. The setup may take time but it’s not necessarily like a assembly plant that requires new dies on each design.

Re:James Webb is fully deployed by lisper on Saturday January 08, 2022 @04:32PM (#29856525)
> double the data

Yes, but the data has diminishing returns as well.

The real value in a second unit is having a backup in the event of a total failure of the first. But that's a hard sell to the taxpayers who fund these things.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:04PM (#29856867)
> Yes, but the data has diminishing returns as well.

I find that hard to believe considering there's literally a universe of things to look at. We find surprising things everywhere we look.

Re:James Webb is fully deployed by caconym_ on Saturday January 08, 2022 @05:59PM (#29857470)
It's not quite the same thing, but as an analogy: should we have built two CERNs (edit: LHCs, not CERNs) to "find" the Higgs boson faster? Or was it better just to build one, expecting that it had a good chance of finding the particle and other new physics, and then put future funding toward different/more advanced and capable instruments that will give us a window into even higher energies/entirely new observation spaces, rather than just accelerating our search of the same spaces by low integer multiples?

My understanding is that the JWST opens up new observation spaces, specifically very distant and highly redshifted objects that Hubble couldn't capture. So we should have a lot of data on a new class of objects in fairly short order, and thanks to the cosmological principle we can expect to see similar distributions of the same objects and phenomena no matter what direction we look in. As we gather more data, we will converge on an understanding of these new spaces, and eventually the error bars will shrink to the point where further observation is generally not giving us much new information.

Is it better to build more JWSTs, to accelerate that convergence by low integer multiples and similarly increase the chance that we'll happen to point one at something truly new and "surprising"? Or should we spend our money on bigger and more capable instruments that we know will give us access to entirely new observation spaces that are completely out of reach of the JWST and other extant instruments?

I don't think it would be such an obvious question, if we weren't constantly getting better and better at designing and launching large and complex instruments. As things stand, we can let JWST and its ilk blaze the trail, then follow up with cheaper instruments building on lessons learned and our general technological and economic progress.

Re:James Webb is fully deployed by CamperBob2 on Saturday January 08, 2022 @09:13PM (#29859163)
It's not quite the same thing, but as an analogy: should we have built two LHCs to "find" the Higgs boson faster?

Depends. Is experimental time at the LHC anywhere near as competitively-rationed as it is for a space telescope like Hubble or Webb?

Re:James Webb is fully deployed by caconym_ on Saturday January 08, 2022 @11:34PM (#29860148)
I don't think Hubble or the JWST have much to do with the question of whether we should have built another LHC to collect data twice as fast, except as an imperfect analogy to help frame the question in casual consideration—i.e. the reverse of the analogy I made in my comment.

In fact, answering that question should come down to whether we expect the LHC to realize the majority of important observations "in range" of its instruments within its projected lifetime, and also in time to make useful contributions to the selection and design of future experiments.

To answer your question directly: yes, AFAIK the LHC is fully utilized; when it's not running, it's down for maintenance or upgrades, and its observations are (or have been, in its active periods) in high demand. But it's far from clear that building another one would yield a good return on investment, especially given the opportunity cost of diverting funding from future experiments.

Re:James Webb is fully deployed by Beldin on Saturday January 08, 2022 @05:22PM (#29857084)
$3-5B would go a long way to a new Einstein telescope (ie. gravitational waves detector). It would likey allow for significant sensitivity increases in the existing ones. It could propel the National Ignition Facility or ITER forward. It could be used to build a new Arecibo. It could add an enormous amount of low-frequency telescopes - or other scopes for very large integrated scope arrays.

I'd much rather broaden our view than double it in one narrow band. (Or advance fusion research.)

Re:James Webb is fully deployed by mattkrause on Saturday January 08, 2022 @10:21PM (#29859653)
For reference, the entire NSF budget is about $8B (maaaybe $10B next year!).
Re:James Webb is fully deployed by lisper on Saturday January 08, 2022 @05:33PM (#29857187)
That's not true. The potential for surprises gets smaller and smaller the more data you collect. The Webb will produce surprises at first because it is able to make new kinds of observations that were not possible before, but after a while that new data will be used to improve our models and subsequent observations in the same regime will (almost certainly) be less surprising as a result.
Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:51PM (#29857387)
> The potential for surprises gets smaller and smaller the more data you collect.

Mathematically, you are quite correct.

But do you really believe that with one little ole' telescope pointed at the freakin' universe you're going to reach a significant point of diminishing returns?

It's like saying if you invent the first microscope, and discover bacteria, why bother with another one?

Re:James Webb is fully deployed by terramex on Saturday January 08, 2022 @06:28PM (#29857770)
> It's like saying if you invent the first microscope, and discover bacteria, why bother with another one?

Exactly, why bother with discovering millions of bacterias with 20 copies of the same microscope if for the same cost can build 5 different microscopes allowing discoveries of thousands of fungi, viruses, protozoans, algae, plankton etc.

In astronomy there are multiple bands to observe - gamma rays, x-rays, EUV, UV, visible light, near-IR, far-IR, short/medium/long radio waves. There are also gravitational wave observatories and special instruments like spectrographs and coronagraphs for imaging exoplanets. Every of those observations needs highly specialised instrument but brings a lot of new insight about what is happening in the universe.

Most of Hubble's groundbreaking discoveries came in first 10 years of its operation. Less in next 10 years. Even less in third decade. In fact its final service mission had been cancelled once but was reinstated once it was clear that JWST will be massively delayed and risky. For combined cost of Compton (gamma/high x-rays), Chandra (low x-rays) and Spitzer (infrared) we most likely could have built and launched another Hubble, but there was no point as those 3 generated much more valuable science than another Hubble ever would.

Re:James Webb is fully deployed by mlyle on Saturday January 08, 2022 @11:59PM (#29860316)
> But do you really believe that with one little ole' telescope pointed at the freakin' universe you're going to reach a significant point of diminishing returns?

I believe that James Webb has some unique capabilities, and a whole lot of overlap with other instruments, too. For things that you can only do in infrared, we have Herschel's history of observations, and VISTA. Sure, JWST is bigger and up at L2, and will be better overall, but VISTA's instruments have some advantages.

Not to mention all the other telescopes and ways we have of studying the universe.

There's all kinds of other things the government has spent $3B on in the intervening development time that I'd trade for another JWST. But it's a bit moot, here: NASA didn't have another $3B to spend. If you made JWST $3B more expensive, you'd not get 2 telescopes instead of 1: you'd get 0, because JWST almost died because of cost overruns.

(And even if NASA had $3B more--- there's a lot of other things that might have been better to do with it than JWSTx2).

Re:James Webb is fully deployed by richk449 on Saturday January 08, 2022 @06:23PM (#29857715)
I wonder what the optimal number of James Webb space telescopes would be? The cost per unit as a function of number built has been debated, but what about the marginal utility (benefit) ? If you built two instead of one, you would get lots of benefit from the second - an entirely independent set of scientists could decide what to do with it, and maybe explore entirely different subjects. If you made ten thousand of them though, the last one would be nearly useless, because there aren’t enough smart people to make proper use of it. My guess is that after a couple of them, the marginal utility falls off very quickly.
Re:James Webb is fully deployed by kragen on Saturday January 08, 2022 @06:18PM (#29857665)
You might see more new things if you spend the next US$4 billion on a different instrument instead of a carbon-copy Lagrange-point infrared telescope. But you're right that you also might not.
Re:James Webb is fully deployed by monocasa on Saturday January 08, 2022 @04:47PM (#29856672)
I think it's more that this argument can be continued ad infinitum. Yes the JWST had significant cost overruns, but in the design phase these types of projects necessarily are looked at as how to best utilize a fixed size grant of money. At the end of the day the decision got made to make a better single telescope than to make two simpler telescopes.

I wouldn't be surprised though if we start to see clever design proposals coming down the pipeline, like several cheaper telescopes, swarm designs for giant radio telescope arrays, and even amateur designed and operated space telescopes. Remember that the JWST started it's design phase back in 1996, and the economics of space launches have changed considerably since then.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @04:51PM (#29856716)
I remember having manuals printed in the 1980s. The first manual cost $1000 to print, the second one $1. This was with camera-ready copy. Never mind all the cost of writing the manual, proofing it, and formatting it.

When I worked at Boeing, the first forging of a part cost $250,000. The next, just a handful of dollars.

At Boeing, the first airplane gets a ton of testing, as the design is being tested. Airplanes #2 and on only get tested to verify it was built according to the design, at a tiny fraction of the cost of testing #1.

Re:James Webb is fully deployed by mlyle on Saturday January 08, 2022 @05:02PM (#29856840)
You still don't choose forging as a process to make quantity 2 (unless you absolutely need forged parts for strength). Instead, you're milling two parts from billet.

Milling 2 parts from billet is cheaper per unit than milling 1 (some shared setup and programming costs), but it's the same amount of raw material and basically the same amount of operator time.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:09PM (#29856924)
You're right that a one-off forging is so expensive that a hogout will be used instead. My point was how expensive one-offs can be compared to multiple ones, and I used extreme examples as illustrative.

Even in custom machine work, the cost is in the setup. A machinist can make two identical cuts on two parts for not much more cost than one cut on one part.

Re:James Webb is fully deployed by nabla9 on Saturday January 08, 2022 @04:40PM (#29856605)
>you'll get double the data for another 30% cost.

Sending just another similar telescope that provides more same typed data (wavelength, angular resolution) is probably not worth it. Spending the same sum for different type of telescope would be better use of the money.

Hubble, Hershel and Webb were are made for different wavelengths, they are complementary.

The Extremely Large Telescope (ELT) is ready around 2027 and it will be the next revolution. 0.005 arc-seconds compared to 0.1 arc-seconds of JWST. (978 m2 vs 25.4 m2 collecting area)

Re:James Webb is fully deployed by hypertele-Xii on Saturday January 08, 2022 @04:54PM (#29856740)
Doubling the data will also double the processing requirements for that data. The observatory is just the remote part of this operation. The data doesn't do squat unless stored, analyzed and interpreted by expensive professionals on expensive equipment.

It's like saying if you're gonna build a chip fab, why not build two while you're at it? Well because the building isn't the operation.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @08:55PM (#29859003)
Why do I have to do all the thinking?

1. Grad students and computers are cheap.

2. Crowd source it. Make the data (and the programs that process it) freely available. Let anyone who wants to analyze it - if they find something cool, they can be famous. They'll do it for free.

3. Processing doesn't have to be done in real time. There's no problem with taking 5 years to analyze 1 year of data.

Re:James Webb is fully deployed by hypertele-Xii on Sunday January 09, 2022 @03:34AM (#29861476)
All of the above are already utilized, to varying degrees of success, and lack thereof. I believe in this stuff but let's be real, we're exploding fossil fuel to propel a camera into space. Baby steps for global consciousness.
Re:James Webb is fully deployed by ramesh31 on Saturday January 08, 2022 @05:22PM (#29857085)
>I do have some experience with this. I worked for 3 years on the design of the 757. Thousands of engineers spending maybe 5 years on it.

Just wanted to say that's really awesome. The 757 is by far my favorite Boeing jet of all time. They are so overpowered it feels like taking off in a fighter jet. Delta still flies them from LAX to HNL, and it's always so much better than cramming into a 737.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:40PM (#29857258)
I am always pleased to be boarding a 757! I was sad when the front page of the Seattle Times showed one being cut up for scrap.
Re:James Webb is fully deployed by adventured on Saturday January 08, 2022 @10:50PM (#29859851)
> Assuming your figures are correct, you'll get double the data for another 30% cost.

The debate over the cost to build another is largely moot. You'd struggle to find the people to do it for many reasons. The talent is even scarcer than the money.

Re:James Webb is fully deployed by ianai on Saturday January 08, 2022 @04:31PM (#29856505)
Agree. A replica wouldn’t have to be sent to L2 for that matter. Pretty sure a lot of science could be done with even a slow trajectory leaving the solar system, if orbiting something else is infeasible.
Re:James Webb is fully deployed by ascar on Saturday January 08, 2022 @04:48PM (#29856682)
As I understood the engineering of the JWST requires it to be at L2 so it's in permanent shadow of the sun and can keep the very low temperatures necessary for good infrared image quality.
Re:James Webb is fully deployed by nitrogen on Saturday January 08, 2022 @05:12PM (#29856954)
It has solar panels, so it can't be in shadow. IIUC the advantage of earth-sun L2 is it's away from the light and shadow of the earth and moon, while being reachable by radio year round.
Re:James Webb is fully deployed by ascar on Saturday January 08, 2022 @05:46PM (#29857331)
I didn't check for sources again earlier, but this NASA article [1] explains it.

Yea shadow was the wrong word and doesn't actually apply because of the relative size of the sun and earth. However the L2 point is by definition in a straight line Sun -> Earth -> L2, so if the sun would be a single point light source that would block the sun and place the JWST in the permanent shadow thrown by the earth. The point is actually that the sunscreen is always facing earth and sun at the same time to block/reflect a maximum of heat.

[1] https://jwst.nasa.gov/content/about/orbit.html

Re:James Webb is fully deployed by finnh on Saturday January 08, 2022 @06:39PM (#29857866)
It's orbiting L2, not at it. It will have basically constant sunshine, which is good - solar panels provide all its power. (no RTG)
Re:James Webb is fully deployed by richardwhiuk on Saturday January 08, 2022 @08:43PM (#29858934)
It has constant sunshine on one side, and constant darkness on the other.
Re:James Webb is fully deployed by bumby on Saturday January 08, 2022 @04:00PM (#29856197)
This question comes up in every one of these threads and this is the correct response.

If you look at the line items on a build, you might see something like a $200 bolt. It’s not that there was $198 of R&D going into the design of the bolt, it’s that quality management drives the cost. Chain-of-custody, bonding, material testing, witnessing etc. are all part of that effort and they don’t scale like a design spec does.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @04:17PM (#29856382)
If it's a one-off bolt with a custom design, it will likely cost thousands of dollars.
Re:James Webb is fully deployed by bumby on Saturday January 08, 2022 @04:41PM (#29856608)
The GPs point was that subsequent builds would make it no longer a one-off design. My point is that there are other substantial cost drivers that break their assumptions. My analogy of a $200 bolt was not meant for a custom design, but the point stands regardless.

(I’ve worked in a custom machine shop for aerospace, and depending on the tolerances, the actual build is typically not thousands until you factor in all the aspects in my previous post)

Re:James Webb is fully deployed by BurningFrog on Saturday January 08, 2022 @04:33PM (#29856542)
> the benefits of a second one would be marginal compared to the benefits of the first one.

This can't be true.

The benefit of the JWST is the observations it can make Two JWSTs can make twice as many observations as one, so it provides twice the benefit.

In some sense there is a diminishing return in that the most important observations will be attempted first, and and over time the average observation will be less and less important. But surely there is many decades of pent up very important research!

Re:James Webb is fully deployed by simonh on Saturday January 08, 2022 @07:18PM (#29858255)
There is a list of specific questions JWST was built to answer.

* What were the first stars and galaxies like?

* How do stars come to form deep within a dusty nebula?

* What are the atmospheres of Earth-sized worlds like, and do they contain signatures of life?

* How far away do we need to look to see the pristine, pre-stellar Universe?

* How did the early stars and galaxies assemble to give rise to what we have today?

Once these questions have been answered, answering them again with exact copies of the same instruments at the same fidelity does offer diminishing returns. Sure it will provide valuable data for its whole lifespan, but there are diminishing returns. Better to invest the marginal cost of another JWST in a different instrument that gives us measurements the JWST can’t. There will be successors to the JWST, and that’s where the investment should go.

Re:James Webb is fully deployed by BurningFrog on Saturday January 08, 2022 @07:28PM (#29858342)
I know NASA has a reputation for bureaucracy, but I don't think it will be forbidden to use JWST for other purposes than those 5 questions?

It is capable of being aimed at any point of the sky and show us things we've never seen before, is it not?

Re:James Webb is fully deployed by simonh on Sunday January 09, 2022 @04:39AM (#29861834)
That is true, but it was designed specifically to perform certain tasks. It’s capable of much more, but those are essentially bonus stretch goals. Nobody is saying a second JWST would have no value, or couldn’t do useful science, that’s a gross mischaracterisation. There are diminishing returns, that’s all.

We all want more science, the question is what’s the best use of 3-4 Bn in extra funds. The real question is which other future telescopes and space missions would you cancel to get a second JWST?

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @11:35PM (#29860152)
Reminds me of when Seattle finished boring a transit line with their zillion dollar tunnel boring machine, they cut it up and sold it for scrap. Never mind that the machine could have just kept right on boring, extending the line.
Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @05:19PM (#29857052)
JWST was built to see in IR to help us get answers to a set of important questions. The best known one being trying to elucidate the question around the rate of expansion of the universe. We hope to get some answer by looking at objects much further away in space and time with the JWST and getting new estimates for the expansion rate. Something we cannot do today.

You don't need two telescopes to do that, you just need one with a specific set of IR capabilities.

Sure, having twice the imaging power is better, but it's definitely far from doubling the benefits. The lifetime of the JWST is expected to be 10+ years, that's a lot of data that will come to us already, and everything the astronomer community deems important will have time on the telescope.

Just like we only needed 1 LHC to confirm the existence of the Higgs boson and the robustness of the standard model. Building two of those would have been a massive waste of money, it was much better to build one, run experiments, assess the results and then use the money that was saved by building a single one to build new tools with new capabilities to answer the new questions.

Of course the reality of government budgeting is a little bit more complicated than my rosy picture but the point stands.

Re:James Webb is fully deployed by thiagotomei on Saturday January 08, 2022 @05:40PM (#29857254)
A small nitpick: yes, we only needed 1 LHC to confirm the existence of the Higgs boson, BUT we made sure to have two experiments (ATLAS and CMS) looking for it. As far as I know, every modern high energy physics accelerator has had two (or more) sister experiments to cross-check each others!

Of course, it is not a perfect analogy, since the two experiments are not replicas. They try to address the same physics cases, but they were designed, built and are operated in a completely independent way.

Re:James Webb is fully deployed by BurningFrog on Saturday January 08, 2022 @06:28PM (#29857775)
JWST is a general purpose telescope, and the by far most powerful ever built.

It should, if working as intended, be able to observe anything in the sky, and get the most detailed pictures ever seen of them. In wavelengths not seen before.

Without doing the math, there are probably billions of interesting things to point it at, most of which it will never get around to.

Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @06:44PM (#29857918)
> be able to observe anything in the sky, and get the most detailed pictures ever seen of them

That's just not true. JWST is primarily infrared, with some limited ability to observe in visible light (essentially half of the spectrum, no blue or green). It has no capability in ultraviolet, x-rays, gamma-rays, microwaves or radio.

You just can't build a single instrument to "observe anything".

JWST can't do what Hubble can for the most part, and Hubble can't do what JWST will do.

WMAP, Spektr (Russian), Chandra and many other missions all do different things and help us answer different questions with very little overlap.

Re:James Webb is fully deployed by BurningFrog on Saturday January 08, 2022 @07:24PM (#29858307)
You seem to argue against something I didn't say.

I understand it observes a different frequency range than Hubble, but it can still "observe anything in the sky, and get the most detailed pictures ever seen of them".

Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @08:03PM (#29858610)
> but it can still "observe anything in the sky, and get the most detailed pictures ever seen of them".

That's my point: it cannot!

Not all objects are visible at all wavelengths. Some extremely old and far-away objects are not emitting anything in the shortest wavelengths because of red-shifting, and you need infrared capabilities to see them (hence JWST).

Dust clouds are also blocking certain frequencies of light from reaching us, so you need instrument detecting certain frequencies to see through them. But if you want to study dust clouds, well you obviously need a different instrument that will not see through them.

If you care about observing very energetic objects like neutron star, you need x-ray capabilities.

If you care about studying atmosphere of exoplanet your best bet is UV light, and this is why NASA is working on LUVOIR.

It's like saying you can observe anything with an iPhone camera. You can't, if you care about imaging a brain tumor or a broken bone, you need x-ray, your iPhone just won't see through the skin. And if you care about taking a picture of the skin, you can't do that in x-ray.

Re:James Webb is fully deployed by BurningFrog on Sunday January 09, 2022 @10:40AM (#29864156)
> > but it can still "observe anything in the sky, and get the most detailed pictures ever seen of them".

> That's my point: it cannot! > > Not all objects are visible at all wavelengths.

A JWST observation showing nothing is new science. Now we know that object emits no light at those wavelengths even when observed by the most sensitive instrument!

But of course those are exceptions. Most things we point JWST to will be seen in greater detail than ever before, and also in frequencies not seen before.

> If you care about observing very energetic objects like neutron star, you need x-ray capabilities. > > If you care about studying atmosphere of exoplanet your best bet is UV light, and this is why NASA is working on LUVOIR.

This feels like deliberate misunderstandings (conscious or not) of my points. I don't think we can get any further in this discussion.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @11:46PM (#29860231)
Are you seriously suggesting there is no other value in infrared light images? That there's only one thing worth looking at in infrared? That nothing else one points it at could possibly yield a surprise?

I'm astonished. I don't think we remotely know enough about the universe to draw such conclusions.

Re:James Webb is fully deployed by Voloskaya on Sunday January 09, 2022 @09:53AM (#29863696)
> Are you seriously suggesting there is no other value in infrared light images

I have never suggested that no. What I am suggesting, is that if you asked the astronomy community wether they want to spend 3-5B$ into getting an exact copy of the JWST, or spend those 3-5B$ into a different telescope, with capabilities complimentary with the JWST, you would get an absolute overwhelming majority voting for the latter.

We are still going to invest in future IR telescopes, but they won't be exact copy of JWST, they will either be complementary (see the future Roman space telescope) or will just be based on newer technologies and be more powerful.

There is simply little value in getting twice the same instrument for that price tag.

Why didn't we build another Hubble? The US build 18 of those for reconnaissance purpose but a single one for astronomy. Because the astronomy community never chose to spend their budget on that, instead they chose 4 new telescopes, with 4 different capabilities, all different from Hubble. That's where JWST comes from. They could have asked for 4 JWSTs instead, but they didn't because that would be terribly pointless.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:20PM (#29857060)
I remember a NOVA on one of the Mars landers. Nobody had ever landed anything on Mars with a parachute before, so the developers had a massive problem. They built this humongous facility to test parachutes. One design after another failed, for several months. They finally found a design that worked.

I don't know what building a second chute would cost, but I bet it would be less than one thousandth of the cost of #1.

Re:James Webb is fully deployed by godelski on Saturday January 08, 2022 @05:10PM (#29856941)
Honestly that doesn't sound like much money. Especially since these projects aren't solely funded by one country, even if one foots most of the bill. Also, $1bn over it's lifetime is really cheap even just for the US alone.
Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @05:36PM (#29857216)
> Honestly that doesn't sound like much money

Well by comparison, here is the cost of two of the most impactful recent-ish (post 2000) space telescopes the US has launched:

- Spitzer: 700M$, JWST being it's successor. This telescope allowed us to detect an exoplanet through light for the first time, refine our understanding of the shape of the milky way, find candidate objects to be further observed by JWST and many more contributions.

- Kepler: 600M$, this is the telescope that allowed us to understand that planets were not rare at all, detecting more than 2500.

So imagine what you can do with 3 to 5B$. Certainly more interesting things than just doubling your data gathering rate of a single telescope.

Re:James Webb is fully deployed by godelski on Saturday January 08, 2022 @06:01PM (#29857487)
Instead of comparing to other telescope projects maybe better to compare to other mega science projects. Or better yet, other government costs. Though of course we'd need to run a cost benefit analysis.

The thing is that these numbers are big for us and most companies, but these are government numbers and decades of work. Both factors are important. It's $11bn over 24 years, or 458m/yr. I'm happy to pay an extra $3/yr for this project.

Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @07:02PM (#29858082)
> I'm happy to pay an extra $3/yr for this project.

Yes, I think many of us would be happy to. But the reality is that NASA has to fight a pretty ferocious budget battle every year, and often (not always) delay and increase in JWST cost has meant postponing or cancelling other missions.

For example the Nancy Grace Roman Space Telescope, which was deemed the top priority by the decadal survey in 2010 almost got canceled in 2018/2020 because of JWST overruns.

This Nature article is a good read: "The telescope that ate astronomy" [1] (and at the time of the article, JWST cost was "only" at 5B$).

I am very excited about what we will observe with the JWST, but shelling yet a few other billion of dollars out of NASA's tight astronomy budget to get an identical copy, mean we are yet again cancelling or postponing other exciting missions that could help us answer very important questions.

[1]: https://www.nature.com/articles/4671028a

Re:James Webb is fully deployed by godelski on Saturday January 08, 2022 @09:05PM (#29859099)
This isn't so much a limited resource problem as an allocation problem. If US, and western, interest increases in science then funding more missions like these will be more popular and Congress will increase budgets. But budget allocations are low because they are unpopular. We talk about the high costs of these missions but they are close to rounding errors in the US yearly budget. It's weird to me that we argue over pennies when we're spending hundreds with no question. We'd say that's insane if we were trying to set budgets for ourselves. The reason it works it because the total numbers are large and we aren't scaling properly. It's a distraction.
Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @11:52PM (#29860265)
If it makes you feel any better, if I had Gates' money I'd be funding a fleet of probes. Most of the same design :-)

Perhaps the cost of NASA probes is so high because politically they cannot tolerate failure. This drives the cost up 10x, which means it's a self-fulfilling prophecy that failure is career-ending.

Contrast this with Musk's approach to blow them up until they work, and then he has cheap launch vehicles.

Re:James Webb is fully deployed by bmitc on Saturday January 08, 2022 @03:38PM (#29855945)
I don't think that's necessarily the case. For advanced R&D projects like this, it's super difficult to capture all the processes and knowledge the first time around required to build it a second time. I think it would probably be cheaper and faster, but not by such a large amount. Also, given the timeframe of this project, I would estimate that many of the parts may be difficult to obtain again.

There's also the fact that for projects like this, so much is learned along the way that you probably wouldn't even want to build it the same way again, having found better, more efficient, cheaper, etc. ways of doing things.

Re:James Webb is fully deployed by wolverine876 on Saturday January 08, 2022 @04:25PM (#29856448)
> 90% of the cost is probably in R+D of the telescope

While I might have guessed that, IIRC someone at NASA said that most of the cost is parts, assembly, and testing of a massive, highly sensitive, highly unusual custom build. Many (most?) parts are custom made, and even finding vendors to make them again would be difficult - wasn't the manufacturing completed several years ago? Again, IIRC, they said a second one might even cost more.

Re:James Webb is fully deployed by mdavidn on Saturday January 08, 2022 @04:50PM (#29856701)
Projects to widen freeways face a similar diminishing return. The most value arises from the new capability. Each lane thereafter does not yield linearly increasing returns.
Re:James Webb is fully deployed by _Microft on Saturday January 08, 2022 @04:04PM (#29856242)
Why spend money on JWST 2 when you could as well spend it on ... LUVOIR? ^^

https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr...

Re:James Webb is fully deployed by smoe on Saturday January 08, 2022 @07:57PM (#29858563)
There are several space telescope projects under consideration besides luvoir.

Habitable Exoplanet Imaging Mission https://en.wikipedia.org/wiki/Habitable_Exoplanet_Imaging_Mi...

Lynx X-ray Observatory https://en.wikipedia.org/wiki/Lynx_X-ray_Observatory

Origins Space Telescope https://en.wikipedia.org/wiki/Origins_Space_Telescope

Re:James Webb is fully deployed by joering2 on Saturday January 08, 2022 @05:06PM (#29856895)
JWST versus LUVOIR-A... just wow! Imagine difference in quality of pictures!

https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr...

Re:James Webb is fully deployed by terramex on Saturday January 08, 2022 @06:54PM (#29858015)
Actually LUVOIR will most likely have smaller 6 meter mirror to reduce cost and use lessons from JWST construction. It will be simpler design than JWST as it will use only 2 or 3 layer sunshield and no cryocooler (creating equipment that can work at 5 Kelvin was massive issue for JWST). Its main science goal will be examining atmospheres of exoplanets, plus general observations like Hubble.

It will observe in UV/visible/near-IR so its resolution will be higher than JWST's as shorter wavelengths are easier to focus (diffraction limit is a function of wavelength) but it will not be able to see objects at the very end of observable universe as it cannot image in mid-IR or longer wavelengths. There is still plenty of interesting stuff closer to us and it will be "true" successor to Hubble.

Re:James Webb is fully deployed by moffkalast on Saturday January 08, 2022 @04:59PM (#29856802)
taps temple Why go big when you can go gigantic.
Re:James Webb is fully deployed by scottlawson on Saturday January 08, 2022 @03:35PM (#29855911)
Part of the reason is that each telescope has different scientific goals. For example, Hubble is a visible wavelength telescope and we learned a lot from the data it collected and continues to collect. JWST is an infrared telescope designed to see wavelengths that Hubble cannot see, and has a different set of science goals.
Re:James Webb is fully deployed by macintux on Saturday January 08, 2022 @03:34PM (#29855901)
I believe in this case it's not 90%.

Much of the cost here was (on the ground) assembly and testing, given the intricate nature of the setup.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @04:22PM (#29856422)
What about all the costs in developing the test procedures? Obtaining the test equipment. Designing and building the test rigs. Designing, coding, and debugging the test software. Training people on how to do the tests. Endless committee meetings on if the tests are accurate and complete. Failure analysis. I bet they're enormous.

Running the same tests again on another part would be at very little incremental cost.

Re:James Webb is fully deployed by guerrilla on Saturday January 08, 2022 @05:06PM (#29856889)
I wish there were a FAQ. This comes up every single time there's a thread about Webb on HN. Search previous posts. You'll see a hundred answers to your question, some of them well researched.
Re:James Webb is fully deployed by mturmon on Saturday January 08, 2022 @10:35PM (#29859735)
This is accurate, and unfortunately the questioner is going through all the threads repeating naive objections to the legit answers offered by people familiar with aerospace. I know the guy who led the assembly of the JWST/MIRI cryocooler, which was one of a handful of high-risk items on the spacecraft, and all of his team’s time was taken up with assembly, build, integration, and test, not just abstract design. I’ve explained this kind of thing in past threads, but it’s tiresome!
Re:James Webb is fully deployed by henrydark on Saturday January 08, 2022 @04:33PM (#29856544)
Reminds me of the line in Contact: "why build one when you can have two at twice the price?"
Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @04:55PM (#29856755)
Contact was written by a scientist who had no experience whatsoever in building things.
Re:James Webb is fully deployed by yongjik on Saturday January 08, 2022 @05:13PM (#29856971)
That doesn't sound right...

> Carl Sagan played a leading role in the American space program since its inception. He was a consultant and adviser to NASA beginning in the 1950s, he briefed the Apollo astronauts before their flights to the Moon, and was an experimenter on the Mariner, Viking, Voyager, and Galileo expeditions to the planets. He helped solve the mysteries of the high temperature of Venus (a massive greenhouse effect), the seasonal changes on Mars (windblown dust) and the reddish haze of Titan (complex organic molecules).

> For his work, Dr. Sagan received the NASA Medals for Exceptional Scientific Achievement and for Distinguished Public Service twice, as well as the NASA Apollo Achievement Award.

https://www.planetary.org/profiles/carl-sagan

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @05:45PM (#29857326)
I've met Sagan (he came by our dorm for conversation and dinner with the students). He was a great man. He was wonderful to talk to. He has made great contributions to science. He deserves all the credit and accolades you mentioned.

But I doubt he ever set foot in a machine shop. Making things is an entirely different skill.

Re:James Webb is fully deployed by tokai on Saturday January 08, 2022 @06:12PM (#29857614)
Machine shop experience is not related project cost estimations.
Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @09:38PM (#29859373)
Sorry, I'm not buying that. But that notion might be one reason why government projects cost so much.

I've taken apart cars many times. I know when I'm being fed a baloney sandwich when taking my car in for service, and use that to pare down the estimate sometimes as much as 50%.

(For all the women who rightly complain about being scammed by auto mechanics, I can vouch for them doing their best to scam me about 75% of the time.)

Re:James Webb is fully deployed by IAmYourDensity on Sunday January 09, 2022 @06:11AM (#29862260)
I'm not buying it either. NASA wasted billions on the space shuttle and single-use rockets until a programmer from Paypal showed them how to build re-usable rockets. Musk regularly refers to the economics of airliners as inspiration.

Obviously ideas to improve the economics of space exploration can come from anywhere, but one of the first places I'd look would be the Boeing machine shop.

And we haven't touched on human spaceflight, where economy must be balanced with safety. Hmm, I wonder what industry has the most experience with such engineering tradeoffs?

Re:James Webb is fully deployed by tokai on Saturday January 08, 2022 @06:09PM (#29857580)
But who had experience with a twin space science probe project.
Re:James Webb is fully deployed by chrsig on Saturday January 08, 2022 @03:39PM (#29855951)
My guesses:

- due to the time between the start of the project and the end, enough time has passed where there are sufficiently new advances in science/tech/robotics/etc to open up new possibilities

- a second one will probably still cost >10% of the original

- a second one wont yield enough benefit to be worth it

like...the JWST isn't anything like hubble, and can do things that hubble cannot. So it's not like a fleet of hubbles would equal one JWST or something.

Re:James Webb is fully deployed by halfdaft on Saturday January 08, 2022 @04:51PM (#29856713)
After reading / watching all the info on this page [1], I find it very hard to imagine even the tiniest reduction in cost in going from 19 insanely complex mirrors to 38, then there's all the insanely complex instruments. It might even be the case that the super specialised and expensive machines that were built to construct the telescope itself wouldn't be able to produce 2 full telescopes without being upgraded / refurbished, hence costing a lot more. Everything about this ambitious project is probably once-off for a very good reason.

[1] https://www.jwst.nasa.gov/content/observatory/ote/mirrors/in...

Re:James Webb is fully deployed by lazide on Saturday January 08, 2022 @03:34PM (#29855899)
When it takes so long to build, it’s already obsolete by the time it gets launched.

If you made a new one every year, it wouldn’t be so bad of course, but a decade+? Oof.

It was so bad they kept redesigning it mid way through to upgrade things as new discoveries were made, which caused even more delays.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @04:22PM (#29856427)
> redesigning it mid way through

And that doesn't have to be redone when making a copy.

Re:James Webb is fully deployed by lazide on Saturday January 08, 2022 @05:46PM (#29857332)
Except it will because no one wants an exact copy, because if you do it at the same time that’s twice the rework, and if you do it later, you’re building something you know is obsolete. No one can resist throwing in some upgrades.
Re:James Webb is fully deployed by loonster on Saturday January 08, 2022 @03:56PM (#29856150)
The Hubble telescope wasn't unique. It was simply the first one that was pointed away from earth.

For the JWST, is there even room for a 2nd telescope at L2?

Re:James Webb is fully deployed by ajuc on Saturday January 08, 2022 @04:13PM (#29856355)
There's room for a lot of them, it will be in orbit around L2, not exactly in L2.
Re:James Webb is fully deployed by baq on Saturday January 08, 2022 @04:57PM (#29856782)
Space is huge.
Re:James Webb is fully deployed by varajelle on Saturday January 08, 2022 @05:34PM (#29857195)
But L2 is just one point
Re:James Webb is fully deployed by CamperBob2 on Saturday January 08, 2022 @05:47PM (#29857346)
That's an abstraction. In reality, what we call "L2" is an orbit around the L2 point. No shortage of room.
Re:James Webb is fully deployed by loonster on Saturday January 08, 2022 @10:47PM (#29859831)
I was thinking since the point is so unstable, the orbit must be extremely small...

Boy was I wrong. The orbit is about the same size as the moon makes around the earth. [0] Its HUGE. We would run out of material to make satellites before we ever ran out of room.

[0] https://jwst.nasa.gov/content/about/orbit.html

Re:James Webb is fully deployed by WalterBright on Sunday January 09, 2022 @02:21PM (#29866454)
It seems that NASA and the Soviet Union used to build duplicates.

https://flyingbarron.medium.com/the-james-webb-space-telesco...

Re:James Webb is fully deployed by mhh__ on Monday January 10, 2022 @01:52PM (#29879648)
They technically did build duplicates of some (not exactly which missions, possibly all) rovers because of the communication delay i.e. you practice the dance moves on earth then send them to mars since you can't really do anything once it gets going.
Re:James Webb is fully deployed by Server6 on Saturday January 08, 2022 @03:34PM (#29855890)
Why would we need two? I would think the next one 20+ years from now would hopefully be exponentially better.
Re:James Webb is fully deployed by alimov on Saturday January 08, 2022 @03:37PM (#29855925)
So that more researchers have access. Afaik access is shared and researchers have to make a proposal and get it approved before use, which to me suggests some kind of queue
Re:James Webb is fully deployed by mrtnmcc on Saturday January 08, 2022 @04:03PM (#29856226)
Queueing researchers should be fine given the universe will be around for a while.
Re:James Webb is fully deployed by mendigou on Saturday January 08, 2022 @04:40PM (#29856600)
Next time you have to wait for your code to compile we'll say "should be fine, computers will be around for a while".
Re:James Webb is fully deployed by ajuc on Saturday January 08, 2022 @04:11PM (#29856329)
In 10 years we can send a bigger, simpler, cheaper, one-piece, non-foldable telescope in Starship for a fraction of the cost. The biggest saving wouldn't even be the launch costs - it would be the simple design allowed by relaxing the volume and mass constraints.
Re:James Webb is fully deployed by wolverine876 on Saturday January 08, 2022 @04:28PM (#29856483)
If only most of the cost was folding it (and if only Elon Musk's solutions somehow changed all the problems to fit them).
Re:James Webb is fully deployed by BurningFrog on Saturday January 08, 2022 @04:06PM (#29856260)
To get twice the science done, of course.
Re:James Webb is fully deployed by bokchoi on Saturday January 08, 2022 @03:40PM (#29855965)
Redundancy would be good reason.
Re:James Webb is fully deployed by spaetzleesser on Saturday January 08, 2022 @04:56PM (#29856766)
The technology is pretty outdated already at launch time. I think they take the lessons from this one into the next telescope.

There is also the question of the part if the spectrum they are looking at. The JWST is for infrared so I assume the next one will be for different frequencies.

Re:James Webb is fully deployed by brohoolio on Saturday January 08, 2022 @03:38PM (#29855946)
I was wondering that myself. How much would a second Webb cost? Or three? Or a fleet of smaller ones.

I’m assuming all of this was looked at, just curious what the answers to these questions.

Kudos to the team! Huge accomplishment.

Re:James Webb is fully deployed by WalterBright on Saturday January 08, 2022 @08:58PM (#29859031)
After reading all these replies, I'm glad Musk never listened to people who said he couldn't make a cheap, reliable rocket that could land on its tail.

grump, grump, grump

Re:James Webb is fully deployed by Voloskaya on Saturday January 08, 2022 @10:08PM (#29859571)
Your point is completely unfair.

Sure if our goal was to mass manufacture a "cheap and reliable JWST" we could, with a lot of money, create an entire assembly line and benefit from economies of scale. And then what? What are we supposed to do with 100s of JWST? It's cool they only cost 200M$ each now, but we don't need them.

What we need after JWST is a different telescope with different technologies to answer questions that JWST cannot answer and to follow up on the discoveries from JWST.

SpaceX and Boeing are responding to a scale problem: getting as much mass as possible into space, getting as much people as possible from point A to B. You solve a scale problem with scale.

JWST is science instrument, looking for answer to specific questions, once those answer are found we will want a different instrument to answer different questions. Scale does not help. Multiple JWSTs cannot see what a single one can't.

Re:James Webb is fully deployed by WalterBright on Sunday January 09, 2022 @03:47AM (#29861550)
Is it unfair?

In Spring 2020, in this forum, the vaccine experts here told me in no uncertain terms that a vaccine would take 18 months to develop. I said it could be done in 6 if all the slack was removed, and things done serially were done concurrently. I was told that was all completely unreasonable and impossible.

6 months later, the vaccine was released.

The JWST has what, 390 single points of failure, and cost $10B. I.e., it cannot afford to fail, so $10B was spent to ensure it would not fail. And it worked! But suppose for $1B one could build a less reliable JWST. They fail like Musk's early rockets, but since they're cheaper the failure is not career ending, and you can iterate the design fixing the things that broke rather than trying to make everything perfect. You wind up in the end spending a lot less money.

BTW, the airplane industry long ago gave up trying to make parts that could not fail. (390 parts that could fail and end the mission is pretty darn risky.) Instead, one makes redundant systems. It is far, far cheaper, and yet more reliable than going for perfection. Yes, it'll be heavier, and that will cost more. It makes airliners heavier, too, and it indeed costs more. But in the end it costs less, much less.

Do I know how to build satellite telescopes? Nope. But I do know how airliners are designed and built. And I know that Musk upended how rockets were designed and built.

As for different technology telescopes, I bet a lot of the telescope could be the same from design to design, just changing the instrument package.

Re:James Webb is fully deployed by rcxdude on Sunday January 09, 2022 @05:18AM (#29862029)
> Yes, it'll be heavier, and that will cost more.

It won't just cost more, it'll be impossible. Aircraft care a lot about weight, spacecraft are obsessed with it, because it's often an absolute limit based on what launch technology you have available and where you're trying to get. JWST doesn't have any spare weight to try to build more redundancy.

> But suppose for $1B one could build a less reliable JWST

Well, the calculus of many single failure points makes this questionable. Even if you're 99% confident in each point of failure, with 390 failure points you have a 2% chance of success. You need extremely reliable components. Also, it's not clear that the majority of the budget is being spent on increasing that reliability: certainly a lot goes into testing, but all of that testing is generally a lot cheaper than a launch and rebuild.

Re:James Webb is fully deployed by Voloskaya on Sunday January 09, 2022 @09:33AM (#29863547)
What I am saying is unfair is your insistence on trying to think of astronomy as a problem that can be resolved by scale.

> that a vaccine would take 18 months to develop. I said it could be done in 6

Cool anecdote. I was also part of those who thought it would be done earlier, we agreed on this. This is not comparable at all.

> so $10B was spent to ensure it would not fail. And it worked! But suppose for $1B one could build a less reliable JWST.

That was the plan, JWST was supposed to cost 1B$, not 10B$. And then we were supposed to start building other telescope based on the lesson learned with that design such as: https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr....

But it ended costing 10B$, not because that's what anyone wanted, but because that's what happens when you try to push the enveloppe. Just like the A380 program ended up costing 25B instead of 9 planed.

> Instead, one makes redundant systems. It is far, far cheaper, and yet more reliable than going for perfection

The JWST does not have 390 single point of failures like the media like to say, a lot of those are highly preferable but not make or break: If the mirror wings failed to deploy, JWST would still work at a lower res. If some of the sunshade layers didn't deploy correctly, it would still work. If the momentum flap didn't deploy, it would still work but require more fuel to keep orbit stable, lowering life expectancy of the missions, Latching mechanisms and release bolts where all designed with tolerance for some of them to fails etc.

There are was actually just a handful of true single point of failures with no redundancy.

> But I do know how airliners are designed and built

Yes I think by now we are all aware since you keep mentioning it in every single one of your comment. And I don't doubt that you know what you are talking about when discussing airliners, but it also seems to me that your experience is a hammer and now everything you see looks like a nail to you.

What I find irritating, is that the team that build the JWST is made of many, many highly intelligent individuals that thought about about how to best respond to the need of astronomy over 25 years, and you seem to think that they are complete idiots that didn't think about solutions and problem that you can think of in 5 minutes on hacker news. They have. A lot of those people come from the world of airplanes. One the biggest contractor for the JWST is Lockheed, which knows a thing or two about designing airplanes and asssembly line.

Hubble, was actually built like that, as it's actually a repurposed KH-11 reconnaissance satellite. Lockheed built 18 of those. Only one of them was ever ordered for astronomy.

So do not worry, JWST is built like it is, not because no one thought about your ideas before, but because they don't help solve what we actually care about.

Re:James Webb is fully deployed by WalterBright on Sunday January 09, 2022 @02:49PM (#29866719)
Apparently NASA and the Soviet Union used to build duplicates:

https://flyingbarron.medium.com/the-james-webb-space-telesco...

so it's not such a ridiculous idea after all.

Intelligence has nothing to do with it. All you have to do is look at the space shuttle design. It was a seriously flawed concept. I did not understand how that concept could have been pushed forward. So I emailed Homer Hickam about it, wondering what I missed. He said I was right, and that he'd also thought the concept was completely wrong. Events later showed both of us were right in every aspect. (I had not expected a reply from him, but he was very nice to do so!)

The Fukushima reactor and the Deepwater Horizon drilling rig were also designed and built by experienced, intelligent people, but they both could have used experience from the airline people. Both had multiple single points of failure, which failed, and none of those points had to be there. I see this again in the auto industry, in particular Toyota's onboard computer.

The software industry is also full of the smartest people I know. Yet I've been able to bring in ideas from airliner design that are of significant benefit. For example, "defensive programming" comes from a talk I gave in the 1990s.

I recommend James Burke's "Connections" series. It is a history of technology, on the theme of how outsiders repeatedly spark advances and innovation by seeing things that the insiders don't see.

I'm an outsider as far as space probes go. I know little about the details. But that also means I am not immersed in the conventional wisdom that develops around the insiders of every profession, and sometimes and outsider can see things the insiders don't.

I don't claim I'm always right. But all I ask is to keep an open mind. Sometimes an outsider with experience in another industry can make a connection.

Re:James Webb is fully deployed by BurningFrog on Saturday January 08, 2022 @04:24PM (#29856443)
I know nothing specific about the JWST, but here is a theory:

NASA is a government agency, which makes what it does ultimately political.

In a political "economy", the return on investments is mainly PR. Politicians aim to get voter sympathy in return for investing $B in NASA.

And voters won't much care if you put up 3 JWSTs or 1.