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James Webb Space Telescope emerges successfully from final thermal vacuum test (phys.org)
345 points by dnetesn 48 days ago | hide | past | web | favorite | 157 comments

Man, I really want this telescope to succeed its mission, but I just can't get over how complex its deployment procedure is. I am extremely pessimistic about it actually managing to deploy as planned.

That's what I thought about Curiosity's skycrane, and that ended up working out pretty well.

Yes, it's complicated, but I'm willing to accept that my intuitions about whether something is too complicated are wrong when we're talking about something that actual rocket scientist have spent millions of hours planning.

I can't let go of my intuition that complex deployment procedures carry an inherent additional risk to the mission.

Now, maybe that additional risk is less than the risk of doing it a different way, but that just means the mission is particularly risky. That appears to be the case with the JWST in any case.

Space is hard. We've failed many times. It seems rational to be concerned in this case.

You can retire risk and accelerate progress by launching more smaller missions and accepting that some of them fail.

The public must be enlightened enough to understand that occasional failure ia a much faster and better and even cheaper path to success.

The science done by a bunch of smaller IR telescope is different from what you can do with JWST. (Basically you are reducing resolution but get better time coverage of transients.)

Yes. But you can retire the risk of technologies like segmented mirrors or complex deployment in smaller missions.

These missions don't even need to be physically small.

Then launch the more expensive one.

You can combine multiple mirrors like they did with the black hole photo.

In this case, the black hole image was created with radio interferometry, in which you can separately record electromagnetic waves from individual radio telescopes and then combine them electronically after-the-fact. Visible and infrared interferometry is much more technically challenging because the frequencies are orders of magnitude too high to record in the same way, and so it hasn't really been successfully applied in space. (See the Space Interferometry Mission[0] for one sort-of attempt at this kind of thing.)

[0] https://en.wikipedia.org/wiki/Space_Interferometry_Mission#I...

This requires keeping the baseline constant to a fraction of the wave length. In other words you would have to position the satellites with a accuracy of 100 nm relative to each other. In other words: No we can not (, yet. For a decade at least).

wasn't there an experiment that used laser interferometry to calculate the precise distances between a constellation of three satellites? I assume something like that could work?

That was the LISA Pathfinder mission (https://en.wikipedia.org/wiki/LISA_Pathfinder), the preparatory step for a gravitational wave detector in space. And yes something like that could work eventually. Right now we are doing science on that concept. It takes a decade or three to get the technology mature enough that you can do astronomy with it.

In some StarLink thread on /r/spacex, someone was mentioning that you can't do IR/optical light interferometry without being able to measure the phase of light, and someone else said we're pretty close to being able to.

If you're able to deploy orbital observatories with a StarLink sort of cadence (keep throwing up cheap satellites as quickly as possible), would you think we'd reach more mature observation tech faster? Maybe observing from Earth is dead long term if you drive innovation up and costs down with the observing systems and the supporting data transport networks.

TLDR How do we make decades of progress in years instead?

Being able to iterate rapidly might be helpful to get tech of the ground into space once we have it. But right now even Earth-bound optical interferometry is in its infancy compared to optical astronomy and radio interferometry. It is an interesting subject of research for method development, but we are far away from an instrument that is sufficiently well understood to be useful.

unless the interferometer is assembled in orbit from several spacecraft. a frame plus three (or more) robotic mirrors.

It does absolutely increase risk, which everyone in the industry recognizes - people talk about things like minimizing separation events as a tool for reducing risk. When you're stuck doing risky stuff like this, you can compensate pretty easily by throwing an enormous testing budget at the thing, which is a big part of the ballooning cost of JWST.

I don't recall ever saying it was too complicated. I only indicated extremely complex, which it is. Millions of man hours have been lost to bad units. Rocket scientists are human.

I'm not sure why you're splitting hairs on this. GP is merely addressing your "extreme pessimism" but now for whatever reason you're either arguing semantics or showing some kind of cognitive dissonance.

Normally they name telescopes once they are on orbit and working, because they don’t want to put a name on something and have it fail.

The joke with JWST is that it’s not allowed to fail.

I have read in other discussions that the contractor has great confidence in the deployment of the sun shield because of their experience with similar systems on classified satellites. I think as long as the launch is successful there won’t be any problems with the mission.

Indeed. The NRO - rumor has it - has been launching satellites to observe the earth in the infrared for years..

Since you are looking at a warm planet you will never get your camera down to 7 K nor do you need to as all sources are close by and bright compared to the astronomical targets for JWST. So the shielding issue is somewhat different. Having Earth, Moon and Sun in the same direction so you can block all of them with a single heat shield is actually one of the reasons why JWST is going to the L2 Lagrange point.

I really hope this is true, but there must still be something different, because there's been years of delay caused by the solar shade not deploying properly.

This is a good take, I like it, the US has deployed tons of spy satellites, and if they think the sail/shield+Mirrors will deploy well because they have used it in spy satellites before then I'll believe it

And this isn't like hubble, where we could (and did) send up a space shuttle to fix an issue after launch. Really scary.

To be a bit more specific, we can't send something up to fix this because it's magnitudes further away from the earth than Hubble is.

JWT will be ~1.5 million km away from earth, in a special orbit around a spot called the "L2 Lagrange point". It's located there so that it can kind of hide in the earth's shadow at pretty much all times and keep all the nearby "bright" things behind the heat shield.

For comparison, the Hubble is ~600km away from the surface orbiting the Earth, and the Moon is a little under 400,000km away from the earth. JWT will be almost 4x further away than even the moon.

I mean, the giddy idiot in me just gets excited about the urgent need for a human L2 mission to fix it.

Likewise. My train of thought goes like

"So what if it fails? There's a lot of money sunk into that! Well, maybe someone would actually decide it's worth going to the L2 to fix it, wouldn't that be cool!!"

So yeah, not the only idiot...

We would probably do this robotically.

"What do we do when the robotic satellite fails?"

"Send another robot!"

Thank you. I was hoping to post these!

"What do we do when the L2 point is filled with broken robots?"

Could that happen?

Unclear. L2 is an unstable Lagrange point, so the robots wouldn't just stay put. But that doesn't mean they would leave, either, necessarily. They could end up in funky Lissajous orbits and go flying through L2 regularly.

The orbital mechanics around Lagrange points are weird.

If SpaceX’s Starship/Super Heavy (née BFR) actually pans out, it should be able to easily perform this mission.

With the irony being that if BFR pans out, this mission could have ended up being launched on it and eliminate a pile of complexity in the process. The mirrors wouldn't have to be hinged, for example.

Imagine going back to 1984, and telling the Hubble successor team "Just wait for a future heavy commercial space launch before planning any larger telescopes".

Or to 1997, and telling Goddard "Your specs will require technological development that we feel should be halted until a commercial spaceflight program develops. We're pretty sure next year someone will found a e-commerce business that will make him a billionaire, and he'll sort it all out."

Or to 2002, when tech internet tech was booming and paypal was going IPO, to tell TRW that the $824 million they just acquired should be put on a shelf until about 20 years later.

Or to 2005, 12 years before BFR was announced, when it appeared cost growth was a factor (not at all related to northrup aquisitions). Again, 2010 it passed review, 7 years before announcement. Is it really irony or somehow a waste? I don't think so.

(Full disclosure: I'm working on alternative tech to deoployables for large-aperture telescopes, but I greatly appreciate their efforts on JWST, given what we had over the last 20 years).

We also can't fix this, because it was designed to be unfixable. Making it fixable would counter productively make the design more complex.

With a $10 billion telescope dead in the water and the clock ticking, Louis Rossman leads a crack team of Apple repairmen -- specialists in fixing sytems designed to be unfixable -- through accelerated astronaut training for a last-chance human mission to L2! Will they save the day? Or will the inky clutches of space doom the mission and leave them stranded farther from civilization than any human in history?

Elon Musk spots them a SpaceX rocket. Joe Rogan puts them through basic training.

I'd watch this youtube red series

Starring Bill Nye and Neil deGrasse Tyson as Bill Nye and Neil deGrasse Tyson.

Can't wait for the theater version, starring Louis Rossman!

Minor nitpick, but the L2 point is selected so it doesn't need fuel to stay there. It's like a gravity well of the earth/sun system, any object getting a little further from it will get back to it.

L2 is unstable. There are stable Lagrange points that would be much better for this purpose if that was the reason.

The unique thing about L2 is that it's the only Lagrange point where the Sun is always blocked by the Earth. That's what they're going for here.

Not entirely true. Spacecrafts orbiting L2 do not stay still with respect to the Earth; rather, they follow a Lissajous orbit, which is quite efficient given the gravitational properties of the L2 point. Therefore, they will observe the Sun quite often. (The apparent size of the Sun from L2 is roughly the same as Earth's, so eclipsing the Sun would be too complicated.) And this is not bad, because otherwise solar panels could never produce the power necessary for the spacecraft to work!

The real reason why L2 is so interesting is that it violates Kepler's third law: despite being farther from the Sun than Earth, the orbital period is still the same as Earth, because of the gravitational attraction of Earth itself. This allows the spacecraft to keep the same distance from Earth during the year, which eases communications with ground stations.

(Disclaimer: I have been part of the Core Team of the ESA Planck mission, which flew around L2 like JWST will do.)

The spacecraft would also keep the same distance from the Earth during the year in Earth orbit, so there has to be another reason they picked L2.

The real reason for L2 is that the sun, moon, and Earth are all the same direction from the telescope when it is at L2, so the sunshield can block them all simultaneously. Yes, the spacecraft will receive insolation at L2 (yay solar power), but it will always be from the same direction and therefore the instrument can be persistently shielded.

EDIT: from the the horse's mouth:

> To have the sunshield be effective protection (it gives the telescope the equivalent of SPF one million sunscreen) against the light and heat of the Sun/Earth/Moon, these bodies all have to be located in the same direction.

> This is why the telescope will be out at the second Lagrange point.


I don't think that's true? At the exact L2 point, the forces are zero, anywhere off that point, they are non-zero, away from the point, from what I understand.

Ref: https://www.space.com/30302-lagrange-points.html "L1, L2 and L3 are all unstable points with precarious equilibrium."

That is incorrect, L2 is not a stable lagrange point, and will require station keeping adjustments to remain in position

They need to use fuel to station keep, there is a hard time limit to this.mission

Is it known how long it would last? Wikipedia doesn't say anything about this issue

The mission is minimum of 5 years with maximum 10 years based on the fuel.


After 10 years it will probably need more than just fuel. And doing maintenance in orbit, especially way out in the L2 point is easier said than done. Probably easier to build a new satellite with even more capability to replace it, except of course that the JWT is famously behind schedule and over budget and a more sophisticated replacement probably won't be any easier to build.

A replacement might actually easier to build. The detector is no small feat, but the major problems with JWST come from the foldable heat shield and the segmented mirror. Both of which are due to size constraints during launch. Basically it has to fit a 20 x 14 m heat shield and a 6.5 m mirror into the 6.4 by 4.6 m fairing of an Arianne 5.

Targeting a rocket with a larger fairing diameter (even at same payload mass) would make the design much simpler. An upper stage with 20 m length and 9 m diameter on a Falcon Super Heavy would allow to have a fixed mirror and heat shield that is only folded once, instead of the crazy origami that JWST is. But of course such an upper stage doesn't exist yet. SpaceX was only started 6 years after the work on JWST started...

What a shame. The mission won't be operational as long as its delays. After all that I'd at least hope there could be an option for re-fueling, but I bet there isn't.

Also Hubble was pretty much a derivative design of existing spy satellites, just fit with some different lenses and pointed in a different direction.

Yes, the deployment looks like a lengthy and risky operation. But the risks don't end there. The Northrop Grumman cryocooler has been a major problem for JWST, requiring years of development and rework. If it fails then some of the most crucial instruments are useless.

This is a good comment. The deployment is eye catching, but the cryocooler was the high technical risk item.

A more complicated process has worked multiple times in orbit already, look up the Orion program and Mentor sats.


For a project this magnitude, I think they should build a spare telescope or two to account for launch failures. Or is it not how the space industry operates?

The costs don't scale quite as well as you'd expect. Actually building, testing, and transporting the thing is really expensive. If you build 2, it's still a lot of expensive bespoke parts. Maybe if you build dozens the economies of scale start to pay off

exactly my sentiment!

why not build two, given the fact that most of the budget is likely to be R&D costs.

Manufacture, certification and launch are still quite expensive. You'd easily run a couple extra billions building a fleet.

Having said that, I'd be delighted to have a fleet of them.

Could you elaborate on the complexity, comparing it to other complex science projects that succeeded? I'm a layman, curious if this is actually riskier than what humanity has done so far.

This video explains it very well. https://www.youtube.com/watch?v=k8yRDrl76d0

Half way through the video, I understood why it's so expensive and risky.

On the other hand, Apollo 11 had many 'firsts' that couldn't be tested before the actual mission and it worked out 'first shot'. Of course there were some problems and Apollo 13 showed that the odd's where not too good.

Huge difference is that Apollo had highly trained human beings on board to fix things that could not be planned for. There were also 10 previous missions to Apollo 11 to work out the kinks, with one failing with loss of life.

JW is not designed to be fixed or fail, nor are there training runs. It HAS to work first shot.

Regarding the 10 missions before Apollo 11: It's a little more complicated. Apollo 1 is the name that was given to honor the astronauts who died in the pad accident. Apollo 2 and 3 didn't exists. But a whole bunch of other tests did exist testing Saturn 5 before we got to the unmanned Apollo 4, 5 and 6 tests. And starting with Apollo 7 humans were included. See https://en.wikipedia.org/wiki/List_of_Apollo_missions for details.

I probably should have known this. I've read alot on Apollo, but never really internalized some of these facts.

People forget there was an entire series leading up to the Saturn V: https://en.wikipedia.org/wiki/Saturn_V#Saturn_development

They've got a Saturn IB at an Alabama rest stop outside of Huntsville. Surprisingly small, but still towers above you!

> People forget there was an entire series leading up to the Saturn V

Well, sooorta. The Saturn V was the third in that series, after the Saturn I and Saturn IB. [0] While there were proposed intermediate Saturns (and ones past V, too) only two first stages were developed, and the V was the only launcher to fly with the F-1 engine.

0: https://en.wikipedia.org/wiki/Saturn_(rocket_family)

The really amazing thing is it took just over a year and a half to get from the first unmanned launch of a Saturn V to the moon landing.

Apollo is probably the wrong thing to compare with, but sky crane did work first shot.

You are right! Sky crane still blows my mind!

Wow, this video is mindblowing.

I think a big amount of the complexity comes from the folded up sunshield. I remember it had torn during a test deployment last year.

Here is a quick animation showing the whole deployment process: https://www.youtube.com/watch?v=vpVz3UrSsE4

If it tears bad it's technically possible to send up a shield that floats near the telescope. There were some plans for that way back during the design phase if I remember right. Still wouldn't be cheap or easy

It looks from the renders like the telescope has solar panels, antennas, etc on the sun/earth-side of the shield. Wouldn't sending a standalone shield screw that up as it would shade them?

Probably, although you could shape the shield not to.

It's still far more complex than just attaching the thing right to the telescope. And glancing starlight leaking in between the shield and the telescope could be a big problem.

I looked it up, the original proposal was actually to use a mobile shield to occlude far away stars for direct planet imaging. I think a similar approach could "fix" JWT but let's hope we never get there

For one, I think it has an astronomically (ha) high number of single-points-of-failure. A quick Google search reported 344.

One imagines that for every single point of failure they've got some kind of plan for how to still derive scientific value while operating it in a degraded state, similar to how Hubble was able to take pictures before service mission 1 and COSTAR.

I'm a layman too, and just watched this https://youtu.be/bTxLAGchWnA to better understand the complexity.

I'm incredibly nervous as well. If a second telescope had to be built for whatever reason would it take as long and cost as much as the first? Or is all the cost and time due to R+D?

I have great faith in it. The "deployables" crowd knows their stuff and all eyes are on them right now.

Anyone know if there are any well paying jobs in space programs of any kind? I've been seeing a growing number of reputable universities offering a wider range of space / aerospace / engineering offerings* and I've been getting curious what's out there. Only issue is, a lot of places I looked pay well below market rates :/ (at least for software engineers). I'll admit my expectations might be off considering I've been in the NYC area for a while now, and am used to seeing NYC salaries, but the pay is well below half of what I would make now and the cut seems too drastic even in a LCOL area.

* I'm mostly talking about masters programs here.

Just a bit of warning: Software Engineering in Aerospace is NOT fun. You're basically in a supporting role to the hardware and system engineers designing the spacecraft. It's pure drudgery... process to the point of absurdity, specs and tasks being spoon fed to you with little room for creativity and/or problem solving, etc.

The pay, benefits, and level of respect on the job reflect all of that.

If you really want to work in space, I'd go and get a MS (or higher) in aerospace engineering or space systems engineering and work at the systems level.

I got out of aerospace and am much happier for it.

To be fair, the reason for this is that if you try to be creative and don't follow strict processes, things fail a million miles from Earth or blow up entirely.

Oh, I admit there are good reasons for it. And there are people who prefer such a rigid, structured, and slow-paced environment. I ran into plenty while I was stuck doing that sort of work.

Good for them. The world needs such people, probably in much greater numbers than it needs people like me -- if it needs people like me at all :)

Nothing wrong with that. But you should know what you are getting into.

I really like building software that's rock solid. I never did aerospace systems, but I'm sure I'd be happy in that space.

Sadly, no need to fly me to the hardware to apply patches... :-(

You mean the strict processes that strictly demanded mixing imperial and SI units ?

The strict processes that got even more strict after they realized they weren't being strict enough when they mixed imperial and SI units.

> You mean the strict processes that strictly demanded mixing imperial and SI units ?

You're describing a mistake that happened literally 20 years ago. Don't you think they might have changed the processes in all that time?

Agreed. I have talked to people at JPL and all their tools are completely outdated, they have no room for creativity and everything they do is constantly watched and reviewed. Unless you are way up in leadership this doesn’t seem much fun.

Maybe it works at a startup where they try do something completely new but as soon as your stuff gets close to production it won’t be much fun.

This is an over generalization.

There’s a big range of agility at JPL depending on how close your work is to spacecraft operations. Here are two current job openings placed by good groups at JPL that many people here would find challenging and innovative —

https://jpl.jobs/jobs/2018-9779-Senior-Software-Engineer-Aut... (group webpage: https://ai.jpl.nasa.gov/)


I think what they build doesn’t run on any probe but on Earth so the world doesn’t go under if they make mistakes . It’s the same in medical. The closer you get to the patient the more regulation you get.

I worked for that AI group for a little while 20 years ago. It was one of my favorite jobs, but did not pay competitively (maybe it would've if I'd had a degree) and you're right that my code never flew (though others had better luck there).

Oh, to continue the theme I also interviewed for a couple of startups spun off by JPL people. The one that got to an offer offered way less money than the big internet company I was also interviewing with then.

I agree with your medical analogy.

Like I said, there’s a range of work at JPL, and some of the autonomy work by the linked group most definitely has run on Mars and in Earth orbit.

Thanks for your insight. I was actually eyeing the "space systems engineering" degrees. If I did ever make a move I'd probably want to transition from the individual contributor software engineer to something higher level (like you say, systems level). Space seems super interesting from the outside looking in, but I supposed there is a lot of careful work involved given the higher stakes, which makes the process much slower than most software companies.

Probably won't actually make the switch, but just interested in seeing what's out there I guess.

I have to agree with this. Tons of extremely smart people, but day to day was hell in the software side.

I had to agree. Never thought that web development would be more than aerospace software development. Hopefully, our project will change that part.

Just adding on to this. The government funded research labs and DoD contractors I've had offers from have been seriously sad, which makes me concerned on the quality of their missions, personally. Also it's frustrating because I'd much rather work in that space. I'm a senior dev making ~140k and was just offered 80k in a higher cost of living to manage a team of 10 developers with TS clearance working on spy satellite imaging. I don't consider myself a particularly strong developer, so who is taking these jobs?

That's definitely a lowball offer.

Government research labs are on the GS scale (mostly). We're capped at $166,500/year in the DC/NY/SF area (and also, as it happens, the Denver area). $80k is what we offer fresh-outs. A senior flight software engineer managing ten developers with a TS should be near if not at the top end of the salary range.

Contractors doing that work should be similar or higher. I've tried to convert contractor senior flight software engineers to civil servants, and I couldn't... because our ~$150k/year offer was $30k/year too low.

Here are the GS pay scale tables. The job you've describes should be either a high GS-14 or GS-15. So, $133k/year and up.


If it was direct government employment did they clarify final salary? There's the 'salary' and then the locality increase [1] which is a base of around 15% and goes up to 28% for places like DC. 102k (1.28*80) is still not worth it especially without prior federal service as you have pension vesting etc to wait for before your benefits are worthwhile.

[1]: https://www.opm.gov/policy-data-oversight/pay-leave/salaries...

Fixed math.

That company might've just been lowballing you. I'm much closer to your current salary at my job and I'm not management or a particularly senior developer. If that was a job direct from the government, they might've put you on the GS scale, which sucks (although you don't need as much in retirement savings if you have a pension that pays 40% of your salary)

That's really weird... I made more than that as a jr engineer doing imaging satellite flight software. Most of us are over 100k in the Denver area.

Can you name companies?

I can! Denver: Northrop Grumman, Level 1 software engineer, 75k. Denver: Northrop Grumman, level 2 SWE, 82k. I talked to lots of colleagues at my level while there and they were all within 3k of those numbers at those levels.

I'm betting that in 5-10 years, there will be an explosion of aero startups. But fast and loose don't work as well in space, where everything ends up going 11,000 meters per second at least. The culture will necessarily be a bit more conservative, and as others have mentioned, software is usually a supporting element at best, a necessary evil at worst.

With launch costs falling and hardware getting smaller/lighter it's getting less conservative. It used to be everything was C99, VxWorks and SPARC or worse but a lot of companies are starting to look at newer technologies. Good luck finding one of those projects right now but it is happening.

You can have a look at ours: https://www.exodusorbitals.com

Cube sats don't count :)

The requirements and budgets for them mean that they're much more expendable than something flying on a full size bus. As such, the level of risk tolerance is much higher.

Even CubeSats today still use the SPARC (LEON) since it's easy to implement on a FPGA as a soft core. I'm personally not fan of SPARC though.

> Only issue is, a lot of places I looked pay well below market rates :/ (at least for software engineers)

aerospace places tend to just have one engineering rate, and it's dominated by what aerospace engineering graduates cost. which is less than what software folks cost.

aerospace graduates are all high on hubble pictures and "we're doing spaaaaace!", so they charge way less.

ESA in Europe has decent salaries and you don't pay income taxes from them

what puzzles me all the time is why not build two instead. it looks like the R&D portion of the budget might be greater than the actual manufacturing cost, so building two would be less than 2x the price.

if one launch fails, we've got a backup. if both launch, we have two instruments deployed.

why don't we do it??

The NASA-Congress decision making complex is kind of a monster. Often makes lot of penny wise, pound foolish decisions. (I should say ${X-Body}-Congress decision making complex is like that).

NASA sometimes does it. Mars 2020 is an upgrade of Mars Science Laboratory (aka Curiosity) spare.

“The first rule of government spending is build two at twice the price” — S. R. Hadden

Generally they do build two - one as a ground testbed for interpreting diagnostic data, trying to reproduce issues, and testing software changes/commands.

However, at the very low rates we're talking, everything is (damn near) hand-built. Economies of scale don't kick in until higher volumes.

Is there any economy of scale? Why not wait until the first one fails to build another one?

Because that requires keeping all the specialized machinery and knowledge alive for the duration of the whole project.

Given the length of this project, I wouldn't be surprised if at this point NASA couldn't order a second one built even if they wanted to.

The unfortunate thing about advanced technology is that if you don't use it, you lose it. More specifically, you lose the research and machining setups and people with knowledge about them in their head; the main problem here being that documentation doesn't capture everything - a lot of tacit knowledge is captured in e.g. tuning of the machines, undocumented fixes made on-site, idiosyncrasies in manufacturing steps, etc.

Unfortunately that's already the case with many long running projects. A friend of mine that works on JWST recently fixed a mistake that was made by someone who retired 10 years ago.

I would expect the R&D costs to dominate.

One does not even need to consider economy of scale. For example, if the R&D is $1 million, and manufacturing one mirror costs $100k, the total price for two mirrors is $1.2 million vs. $1.1 million for one.

Plus, consider a non-zero probability of a launch failure.

At this price point it better be good. It has to make up for all the other astrophysics missions it killed with its (near) endless budget overruns.

That's a bit cynical. There are many examples of NASA missions that had far exceeded the original expectations.

Plus, check out some of the engineering on this $10B masterpiece.


In my opinion, much better for Human advancement than the typical $10B infrastructure project

indeed, I would take a bunch of 10billion scientific instruments over trillion dollar fighter jets or mid east military incursions any day.

Yup. Hubble was no different; took forever and cost more than expected. These are novel scientific instruments, not helicopters.

Hubble's cost structure is complicated. It is essentially a modified spy satellite and so much of its development costs were shrouded. We don't know how much was saved, or how much of Hubble's public budget was used on other projects. JWST is different. It is a unique object with no equivalent. Its cost structure is therefore not comparable to Hubble.

(Or I am wrong. Maybe JWST is a modified version of a super-secret unannounced program and its budget is covering the development costs of that spying program. Given the testing scheduled I doubt this, but it remains a possibility.)

Part of the cost of Hubble was that the teams working on the keyhole satellites was not allowed to tell the Hubble designers about "lessons learned" and the Hubble team had to find them out the hard way.

Any links or references? Sounds like a fascinating backstory.

I think it's fair to say that JWST isn't just a tweaked KH like Hubble. The mirrors and sensors in JWST are completely optimized for infrared, which is a borderline-useless part of the spectrum for high-res terrestrial surveillance. Optical scopes also wouldn't need the extensive sunshield and cooling systems that JWST will. By the time that a theoretical secret optical JWST-KH were retrofitted with new mirror designs, new sensors, and new active and passive cooling systems for a public infrared science mission, you basically have a completely redesigned satellite.

> There are many examples of NASA missions that had far exceeded the original expectations.

many of those concocted by NASA announcing artificially low public expectations, while ensuring the contractors know what the real (much higher) expectations are.


the whole point is that NASA isn't documenting this. go get a job in the industry and ask around after a couple of years.

Let's assume expectations scale with budget.

The original cost estimate was $0.5B [1]. Now it's roughly at $10B. So there was a 20x cost increase.

So if we assume original expectations it would need to exceed original expectations by 20x just to make up for the cost growth.

Of course we also need to consider all the other NASA telescopes that didn't get funded to feed this one. They all would likely have exceeded expectations too. It's hard to estimate those, but at least a factor of two addition seems reasonable. So it has to be 40x better just to not exceed

BTW nothing of this is cynical. It's just basic cost-benefit analysis.

It would have been better to cancel it early and spend a small part of the cost in technology development (and other more manageable telescopes) to make sure such an epic project disaster never happens again.

You're conflating expected value with investment cost.

Your argument has the same merit as "I need a car to get to a this new job which will cost $1000 and I'll make $100k more." If instead you purchase a car costing you $10k that doesn't mean it's no longer worth taking the job.

This project has advanced our ability to build complex devices, and refined various manufacturing processes that will all have meaningful impacts on our economy and that is before it has started it's mission. The data it will collect is potentially invaluable not to mention the personal inspiration that projects like these inspire in individuals.

Compare this to other ways that our government might have actually spent this $10B over the lifetime of this project and we're still getting a bargain.

Compared to other NASA projects we likely wouldn't have gotten the manufacturing processes or complex integration experience and even more likely we wouldn't have gotten the inspiration. Bigger and more expensive projects are expensive because they're hard. When we succeed in doing hard things and even make the same thing easier in the future we collectively absolutely get more value.

Obligatory xkcd: https://xkcd.com/2014/

2026? Probably not. 2021? I doubt it. My money is on 2023-24.

They already built the damn thing, how hard could it be to land it in stable orbit 1.5 gigameters from the planet? This ain't rocket science, people. Wait a second.

I had !remind me in 2 years setup for it. Didn't really know why, but figured out eventually by how long it's taking them.

Also - isn't the tech behind it is going to be obsolete pretty soon?

Obsolete in what sense?

It is a big digital camera. They dont stay cutting edge for very long.

It is only rocket science if you use rockets. If you get the telescope up with a space elevator then the term no longer applies here.

> one step closer to its 2021 launch

boy, that's gonna be a nail-biter. who's gonna insure that launch?

No one. Or, more accurately, the government self-insures most launches, and eats the cost of a failed launch.

How many megapixels is this one?

The main imager is the Near Infrared Camera. It has ten 2048x2048 sensors. They're configured in two kinda-independent groups with separate optics. Each group uses one of those sensors for longer wavelengths (so you get two lots of 2048x2048), and four of them for shorter wavelengths (so you get two lots of 4096x4096). The two modules can (and I guess usually will) be pointed at adjacent regions of the sky; I expect they'll overlap them a bit so you'll get slightly under 4096x2048 for the long wavelengths and slightly under 8192x4096 for the short. These are monochrome sensors but they have an array of filters they can swap in to measure different wavelengths.

There are several other instruments, including some other imagers.

Considering how much camera sensors have improved in the last few years I wonder how outdated these sensors are (or not)

Edit: makes me also wonder if with all the delays they upgrade any equipment in the meantime.

Hard to tell, since you can't use off-the-shelf sensors. They have to withstand the harsh environment in space, for a very long time, without any maintenance.

They're also specifically designed to operate in absurdly low temperatures — one in fact requires temperatures under 7 Kelvin and so in addition to the sun shield there's a mechanical cooler.


"Only" about 10 years. This has a very complicated orbit and needs to use fuel to adjust and stay on it.

I was working on an in space assembly project at NASA recently although it was in a research department so we were not concerned about using space rated equipment. We were exploring both traditional methods and reinforcement learning. The cameras we were using were 2048x2048 and I asked around about what we could expect to have available if it went to space and I think the best off the shelf space rated camera was about 720p so anything more would need to be custom.

> makes me also wonder if with all the delays they upgrade any equipment in the meantime.

This is how you never launch the damn thing. There is just no way to "upgrade any equipment" without introducing a tremendous amount of paperwork, additional testing, etc.

I seem to remember the detector arrays for MIRI were built sometime between 2005 and 2009. (I worked on MIRI for a time in 2011)

The complete array works out at 937 megapixels. (As of 2011. It may have changed.)


So about 14 smartphones of 2019

Beyond a doubt the sensors on a 2019 smartphone would pale in comparison to what is on that craft, and not just in resolution.

This is so cool!

And hot.

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