81 replies on “Webb Sunshield Works as Expected (In the Lab)”

  1. You mean ‘finally’ the screen didn’t rip after all these years trying? Yep we knew, we were not supposed to know, some were not supposed to tell us, but tell us they did. Now I would like to know the cost breakout analysis over these last many years specifically of the engineering/re-engineering etc. of the tennis court sized shield. The shield development a long term career achievement.

    1. You mean ‘finally’ the screen didn’t rip after all these years trying?

      What are you talking about??

        1. Haven’t been following very carefully, have we?

          Rather than posting snarky comments, how about providing a link or two to support these specious claims??

          In the U.S. we have an expression for such situations: “PUT UP OR SHUT UP”.

          Thank you in advance for your prompt attention to this matter.

          1. No need to shout. You should be able to research yourself or join NSF L2 which is a pay site. I’ve joined and therefore am privy to info’ that’s not in the public realm. Not going to disclose info’ I’ve paid to access. Sorry but that’s the way it is.
            Cheers

          2. I’ve joined and therefore am privy to info’ that’s not in the public realm. Not going to disclose info’ I’ve paid to access.

            And so privy that no one working the program or the various agencies that have audited the project know about it either.

        1. what you’re saying is (or rather, trying very hard to NOT say, but still implying) that the sunshield has been tested before and it did not deploy correctly, or that it ripped, or otherwise failed. i cannot find any articles online corroborating your implications.

          1. I wonder about this test and others like it: how does testing this device in a gravity well help predict how it will behave in microgravity?

  2. Why oh why do they design these things that “have to work perfectly”. Why not design something where they have a fallback in place if it doesn’t work “perfectly”. There will be tears if it doesn’t and the people will shrug their shoulders and say something stupid like oh space is hard you know.
    This is one reason why there is increasingly little bang for buck. These engineering marvels that keep pushing the boundaries and become so expensive that they’re only affordable once in every decade.
    Cheers

    1. Why not design something where they have a fallback in place if it doesn’t work “perfectly”.

      Thank goodness the world has clear-thinking visionary accountants like you to guide us engineering dimwits in our daily work.

      1. Great response to my post. Ask any business whether or not the can get by without beanies? I’ve worked for over three decades in engineering businesses and never seen the levels of incompetence in programmatic and project management as NASA is currently demonstrating in their PORs not to mention some of their cancelled efforts. Show me where I’m wrong.
        Cheers

        1. Ask any business whether or not the can get by without beanies?

          My comment was related to your telling JWST sunshield engineers how to do their job, not the usefulness of bean counters to count beans correctly.

          It has been known from Day 1 of JWST that the sunshield deployment system and other various items are single point failures for the mission. One should remember when playing armchair engineer that the whole thing MUST fit inside the payload fairing of an Ariane 5. I can’t think of a practical and cost effective way to avoid that ugly fact of life.

          1. Well a simple solution would have been to design something that fitted originally without the need for a complex folding shield, even say a heat dispersion system of some sort. There were other alternatives considered you know.
            But it’s too late now and the cost overruns and schedule slips are the result of an inherently complex design. Complexity increases risk and generally leads to increased cost and schedule.
            I stand by what I’ve already said on this project regarding design and management.
            Cheers

          2. Given JWST’s original size (10m) and the launch vehicles available at the time it was proposed, folding it up was the only way to make it fit. A lot of emphasis here is on the sunshield, but people seem to have forgotten that the primary mirror also folds up, and must deploy to sub-micron accuracy. One can make an argument today that given the current mirror’s descoped size, and the impending existence of vehicles like the Falcon 9H, that one could redesign around a monolithic mirror and shade. But now there are huge sunk costs, and the Ariane launch vehicle is the primary ESA contribution to the project, so there are politics there as well.

          3. Cost control means you go with the technology you currently have. That was the Ariane V, n-off. Within 2 years the Falcon Heavy will exist so missions and telescopes starting now can plan to use it.

          4. Gonzo_Skeptic wrote

            One should remember when playing armchair engineer that the whole thing MUST fit inside the payload fairing of an Ariane 5.

            I want a cite from the Bible on that one, enforced by eternal damnation.

            If it a man made rule it is negotiable. Being off the shelf the launch vehicle is one of the cheapest parts of this project.

            For instance the sun shield, mirror and avionics could have been launched separately and assembled in orbit. If deployment of the sun shield failed that a replacement with the design error fixed could have been launched.

          5. Belatedly:

            For instance the sun shield, mirror and avionics could have been launched separately and assembled in orbit.

            Similarly building a non-cooled version first to prove everything bar the cooling system, sunshield, and MIRI. Even earlier, building a smaller non-folding mirror (which otherwise uses the same mirror-segments and primary systems) to prove the spacecraft bus and core systems. Likewise, test just the fold-out mirror system and imager(s) at ISS, on a stripped down platform that piggybacks off ISS power/comms/propulsion, in order to not only test the mirror-system, but create a platform to test other components in-situ.

            But, obviously, building a single, cannot-fail, monster origami telescope all in one go, with a dozen brand new technologies that won’t be tested in space before deployment, launched into an irretrievable orbit with no capacity for repair, is obviously much cheaper than anything I’ve suggested. After all, one is cheaper than three, right? That’s just maths.

          6. Note that it hasn’t failed yet, so a doom and gloom result is only a possibility at this point.

          8. That may be, but I was referring to science and its function. It is possible that its future discoveries could partially justify its cost. Note I said “could.”

    2. An unencumbered observer of human activities in space would surely recognize the first, tiny steps of a baby learning to walk- hell, learning to just roll over. Trying and developing new stuff for space is essential. Suck it up.

      1. Ask your taxpayers what they think of the total failure to control cost and schedule. Any normal business would have seen heads roll long ago due to sheer incompetence thus demonstrated but this is NASA after all where projects are typically now never delivered and cancelled (DC-X, X-33, Cx) or suffer unbelievable budget bloat and schedule slip (MPCV, SLS, JWST).
        I’m not saying you shouldn’t develop new stuff in space but that doesn’t obviate the need for programmatic and project control.
        Cheers

        1. You are perhaps conflating two issues: the need to develop new tech with the need to do it in a financially responsible manner; on the latter you are correct, for the most part; as to the former, your observations are simply short-sighted.

          And, yea, I get the single point of failure.

      2. Belatedly:

        In what way is JWST “tiny steps”? Surely anyone who believes in incremental development of technology and expertise would criticise JWST precisely for ignoring, even actively opposing, that principle. A single spacecraft of a radical design, with a bunch of hideously complex novel systems never tested in space which must all work perfectly in order for the telescope to be usable at all. (If the origami mirror fails for unfold, you don’t just get a less powerful telescope, you get a mission failure. If the origami sunshield fails to deploy, you don’t just lose one experiment, you lose the telescope.)

        If the MSL’s drill failed, MSL still did science. If the laser failed, MSL still did science. If the drill and the laser failed, MSL still did science. But if any stage of the skycrane failed, MSL failed.

        JWST is all skycranes.

        Also:

        I had no idea that thing was so big.

        The stack in the image in the article is just one quarter of the entire sunshade. There are four of those on the full telescope. Starting with the one in the picture, mirror another stack towards the camera, then mirror that pair to the left of the camera.

    3. Yes a backup tennis court size shield. That isn’t folded up. Why didn’t they think of it. They could have self assembled it with a 3d printer in space using carbon nanotubes for trusses and graphene for the shield.

      Why didn’t they just send jwst outside the solar system far enough away from the sun and planets so that the instruments could be cold enough to operate without a shield? They could have used a giant solar sail for propulsion made out of dem nanotubes.

    4. Because is costs more and requires more hands on work and reviews. It is about the pork not the product;

    5. Well, that seems to have attracted some less than sympathetic comments…

      Without offering any opinions on why, I’d say one issue is a deep-set attitude in the aerospace industry about failure. An engineer is expected to design and build something which satisfies certain specific requirements and to verify that it does so. Going into a review and saying, “it may not work because of X, but I made sure the overall system will be fine even if that happens” is almost confessing to failure. That’s not a bad attitude in some cases, but it also creates an institutional bias against making things fault tolerant as opposed to fault free.

      But for JWST, I’m not sure how relevant that is. The design requirements are very demanding. However, this also points to another problem with what is often called “institutional culture.” The existing structure for flight hardware development doesn’t really allow room for back-and-forth discussion of requirements. The user/customer/scientist defines specific requirements. Usually before any real engineering design work, and without knowing what the technical implications will be. The engineers are then expected to go off and build something that satisfies those requirements. I’ve seen plenty of cases where there was no room (or no interest) in any iteration. In specifying the requirements, the scientists don’t really have a place to say “cool to 50 K, unless that’s going to drive the cost through the roof. If it does, I guess we can live with 55 K.” The engineers don’t have a good way to go back to the scientists and say, “doing X is really driving the cost through the roof, can you live with something less demanding.” That can mean unrealistic (or optimistic) requirements and enormous difficulties trying to satisfy them.

      1. A smart answer. I’ve been a professional designer and writer my entire life and seen this play out hundreds of times: a disconnect between users and designers, mostly because the guy paying the bill writes the specs.

        Community development is a case in point. I will layout a subdivision or multi-subdivision community based on my own living experiences, but there’s no input from the folks who will eventually live in those homes.

        It’s also why, incidentally, developers are able to cut corners on certain physical improvements; the cost of maintenance and repair is borne by someone in the future.

        The best I can do is put myself in the shoes of every future resident. It’s not possible, of course.

      2. Well, that’s the difference between “waterfall” and “agile” development. The problem is that agile development is very difficult when working with large numbers of disparate teams that aren’t co-located. And that kind of operation is very rare for big projects, if nothing else for purely political reasons of spreading work between centers and contractors.

        There’s also a large political issue with “too big to fail” projects. If something costs $10B it had damned well better work. NASA doesn’t get to write it off as a risk, because instead you find yourself hauled before a congressional committee.

  4. I only hope that this telescope actually works after the insane amount of funding that has and is being spent on it. Remember Hubble? No such second chance for this one and the science programs overall have suffered cuts for this one project that they may never recover from due to the now flat and decreasing budgets not to mention the other pork projects slipping and continuing to blow their budgets. Seems that programmatic and project management competence has virtually disappeared from NASA.
    Cheers
    PS. Intelligent posts for the most part below guys, well done (they’re not hard to find). If you have anything at all to do with NASA projects then I rest my case.

    1. If things had progressed as they should have in HSF then sending a crew to L2 to service JWST on a regular basis would have been no problem. But things obviously haven’t progressed as they should and so in my opinion starting such a project at this time was premature.

      1. No that’s not possible. JWST has not been designed to enable in-space access for servicing whereas Hubble did provide for such access.
        Cheers.

        1. “JWST has not been designed to enable in-space access”

          Exactly my point. When Hubble was built there was capability to service it. JWST was built knowing full well that similar capability was not yet available at L2 but they “started” anyway. Emphasis on the word started per my original message, because it is one thing to start a project when it was believed there will be capability, as happened to Skylab, Hubble and ISS. In the case of Skylab the Shuttle arrived too late and some pieces of Skylab landed on your continent (sorry about that). In the case of Hubble the Shuttle was shut down too soon and it was almost a fluke that the last servicing mission occurred otherwise Hubble would be dead already. As for ISS the replacement for the Shuttle never materialized and only with some luck are we still able to operate it.

          JWST is a whole different story, they started the project knowing that servicing capability did not yet exist but they went ahead anyway.

          1. I seem to recall that a number of the to-do items on Hubble servicing missions were aimed at parts of the thing that were not considered to be “field-serviceable items” according to its original design. That included replacement of some “non-serviceable” components with newer ones designed to more easily accommodate subsequent maintenance. I suspect the same may be possible for JWST.

            As to possible service missions, the thing won’t even fly before 2018 at the earliest. Even if there’s an early deployment problem, say, with either the sun shield or the mirror, it will probably be possible to gin up a repair mission for launch perhaps only a year or two later.

            Falcon Heavy will have been in service for three years by the time JWST flies. It may even have at least one type of follow-on second stage design available by then that yields improved lift capacity to LEO, should that prove necessary.

            At least one Bigelow LEO station should have been in operation for a year or more at the time of JWST launch as well. Bigelow and SpaceX could easily be already at work by that time on a deep space version of BA330 with a combo chemical and electric engine-based service module that would enable a JWST rescue. The first paying work for such a rig, though, will probably be to carry tourists, researchers and lunar prospectors, Apollo 8-style, around the Moon.

            Commercial space is advancing its capabilities swiftly enough that they will certainly be able to pull any future JWST chestnuts out of the fire for NASA at affordable cost and with only modest delays or interruptions to the big eye’s initial or on-going operations. It would be ironic if all of JWST’s delays wound up allowing time for others to develop what’s needed to assure its future salvation from death by glitch.

          2. Yes we might get lucky and be able to fix any deployment glitches, or extend the life of JWST as parts age, or replace instruments with newer ones built with still to be developed technology. The last Hubble servicing mission demonstrated that is possible however we got really lucky on several of those items. JWST is going to require an even stronger dose of luck if it needs any servicing.

            I am not saying that we shouldn’t ever explore beyond current human presence in space. I have no problem for example with sending probes to the outer planets even though obviously there is no way to service those probes (those that remain in the solar system) as probably that capability won’t exist until later in this century. But it seems like we have gotten away from the emerging ideal of a just few decades ago where we expected that virtually any satellite in LEO would be either serviceable on orbit or able to be brought back to Earth for repair. Challenger seemed to put an end to that dream when in my opinion it shouldn’t have. And of course since that dream seems to have been abandoned then obviously no one even considers any servicing beyond LEO.

            We seem to accept the current economic realities that make disposable satellites the norm, as we have until recently with launch vehicles. Elon Musk is attempting to change the equation on the latter and if he succeeds hopefully that will change the equation on the former also. And maybe the ISEE-3 project is helping to change people’s thinking about this.

            Hopefully we can eventually see an actual commercial market development for servicing satellites in LEO, cislunar space and even Lagrange points. Robots of course can be used also but only for routine and planned servicing. As Hubble has shown when the unexpected occurs you need a human presence.

          3. Agree entirely. It’s going to be quite awhile before AAA has tow trucks roving the Kuiper Belt. That doesn’t mean we shouldn’t design big-buck payloads intended to operate a lot closer in to be field serviceable and upgradable. Certainly anything intended to operate in cis-lunar space should be so designed. JWST, should it ever need on-site attention, will have to be partially and/or incrementally rebuilt as required, but we have the example and experience of Hubble as to how to do such things. Now all we need is the robotic and/or human-crewed tug/runabout technology to do such missions. As noted, I foresee a number of purely commercial needs that should induce development of such. Repair missions for NASA assets would just be incremental additional uses for this technology.

          4. The second of any design is much less expensive than the first. One of the reasons for abandoning the repair mission strategy was that the Hubble repair missions cost as much as building a duplicate telescope and launching it on an ELV. So far however our strategy has been to launch only one of each design. If we are going to have cost effective satellite servicing we need a low cost approach to doing it.

          5. Agreed and as I mentioned it’s the economics of our current technology that leads to disposable satellites, just as it does to disposable launchers. But I think it’s a Catch-22 that we are in because rocket technology has been geared for decades towards disposable, so that creates a self-fulfilling bias towards that method. Musk is trying to prove that if you make reusability a long-term goal then the economics will eventually move in the other direction.

            Unfortunately the Shuttle was a very high-profile attempt at reusability and its failure economically (although not technically) was a setback for reusability. It’s funny Musk has used the analogy of throwing away an airplane after its maiden flight to explain why he is so adamant about reusability, however I remember that same analogy was used to justify the high cost of developing the Shuttle, so I suppose it’s not surprising that so many people have doubts about the economics of reusability until they see evidence of it actually paying off. But unfortunately that is going to take a long time, thus creating the Catch-22 that keeps us bound to the old methods.

  5. The original concept for the ISS (back in the 70’s) was that astronomical satellites would co-orbit and dock with the ISS when servicing was needed. Final assembly and checkout could be done on while at ISS so that any problems could be corrected prior to deployment. The environment around ISS is cleaner than expected and should not present a problem.

    1. Because the ISS is in low earth equatorial orbit, just about the worst place you could put such a thing. Ok, I’ll admit the telecom is a lot easier than L2. But JWST (and virtually everything else on the books) is primarily an IR mission. The heat load from both the sun and the earth are unacceptable. And the combination of the sun, earth, and moon pointing constraints are really a bear. L2 is really the place where everything is going in the future. But we’ll need better telecom (like an optical relay), and let’s pray that whatever is happening to Gaia can be better understood very quickly.

      1. Because the ISS is in low earth equatorial orbit, just about the worst place you could put such a thing.

        No it isn’t. The ISS orbit is inclined over 50 degrees.

        1. From a science mission design standpoint, it’s the same thing. The ISS goes in and out of earth shadow, and the earth is a gigantic heat load as well. When your observations are measured in hours, and you’re trying to deal with earth occultation and a constantly changing sun-earth vector, and keeping power levels up, it’s a nightmare. You’ll still find survey missions in low earth orbit. But those are almost universally in sun-synchronous polar orbits, which simplifies everything – they basically just point out, away from earth, and use the effective rotation from the earth going around the sun to let them sweep the sky in a year. The sun vector is essentially fixed, keeping the panels pointed at the sun and allowing the sunshade to keep the telescope in darkness.

          1. I didn’t say being wrong about the ISS’s orbit invalidated the rest of your thesis – it doesn’t. I agree with you about all that stuff. But the ISS orbit is not equatorial. Just saying.

            I also agree with those who say that doing all of JWST’s mechanical deployments at ISS, then moving it out to L2 on some kind of low-thrust, high ISP tug would have made more sense and cost a lot less than the $10 billion the thing will have soaked up by the time it flies. That could straightforwardly have been part of the original design. The tug would have had lots of other uses apart from pushing JWST too.

          2. Well, that I actually agree with. I have no idea how hard it would be to move the deployed spacecraft to L2 afterwards, though. This also wanders into the political minefield of who actually pays for the manned monitoring of the deployment. The accounting for the HST servicing missions was always very dodgy, and financing the final one caused a lot of pain.

          3. Yeah, I agree about the murky accountancy on HST repair missions. The JWST has soaked up so many budget overruns, though, that giving it some human attention to insure all mechanical deployments are correct before Earth departure would be comparatively trivial even if charged entirely to the project. That may be playing into the sunk cost fallacy, but the sunk costs on the JWST are truly of Titanic proportions. Spending a bit more to insure it wasn’t all wasted just seems trivially prudent.

            It won’t happen, of course, but it would be worth whatever it cost – mainly an incremental ISS EVA or two, plus a few pro rata percent of the cost of a tug – if it could be made to happen.

          4. All I’m saying is that the concept of checking out telescopes at the Station was one of the primary missions of what was then called the Space Operations Center. Pressurized and unpressurized hangar modules were included for this purpose. At that time it was assumed the tug would use hypergolics. But today Hall Effect thrusters are capable of converting any amount of electricity that can be generated into thrust with an ISP >1000. (3000 is seriously discussed). If we can retrieve an asteroid, we can deploy or retrieve a spacecraft from the Earth-Sun L2 point in a reasonable period of time. A reusable solar electric tug could be (as we used to say) an enabling technology.

          5. How long ago was that, though? I have seen an early design concept from the 70s for Spitzer (nee SIRTF), which included hauling the entire spacecraft into a space station cargo bay for servicing. But the space station looks like something from Babylon 5, and was clearly conceived of in a different (and more flush) era.

      2. On the ISS cryocooling for IR sensors could be externally powered and closed loop. JWST is one telescope. The science community needs more than one sensor, and the limiting resource, as always, is funding.

        For scopes that need to go to L2 or other places in space, the concept (back in the late 70’s) was for a space tug so they could assemble and check out astro payloads at the ISS, then push them to final locations. With the impressive thrust available from newer Hall effect thrusters, a solar-electric tug could be a real enabler here.

        1. No, it’s not for cooling the detectors. That’s pretty trivial. The whole telescope assembly, all of it, needs to be at cryogenic temperatures. That is achieved in the modern era by shielding the whole thing from the sun and allowing it to radiatively cool. We’re talking wavelengths of interest longwards of 1.5 microns, and the radiation from a room-temperaturish anything (windows, mirrors, etc) is by far the dominant noise source. All of these modern missions have sunshades of some sort for this reason, it’s just that JWST is monstrously larger than all of it’s predecessors. By the mid-80s it had become obvious that was completely unfeasible to actively cool the entire assembly, and passive radiative cooling was the solution.

          1. it had become obvious that was completely unfeasible to actively cool
            the entire assembly, and passive radiative cooling was the solution.

            The MIRI instrument still needs to be cooled by an active cryo-cooler. So it’s not all passive.

            And when calculating the final cold temperature possible, one needs to consider that the black body radiation of the universe actually does contribute thermal energy ever so slightly back into the observatory. I will leave it as an exercise for the student and armchair engineer to calculate the temperature rise of a black object on the dark side assumed to be at 30 K and using a 2.7 K universe.

          2. Compared to to the energy requirements to theoretically cool the telescope assembly, the MIRI cryo-cooler requirements are pretty tiny, and even then it’s a ridiculously complex device – the amount of plumbing snaking around the spacecraft is pretty shocking. Maybe not for HSF, but for a science mission it’s extreme. The cooling of the telescope is passive. Since this approach is well-proven at this point, I don’t doubt that the cryo-engineers who did it have it right. I actually do this kind of of stuff for a living.

          3. I actually do this kind of of stuff for a living.

            That is clearly evident from your posts.

        2. That, by the way, is why HST no longer has any instruments that function past 2 microns. The heat load from the warm telescope optics means the backgrounds are not that much better than from earth. Large ground telescopes are both more sensitive and have higher spatial resolution. Shortwards of 2 microns and it’s fantastic. But JWST will focus on these longer wavelengths because cosmic redshift moves the optical light down into the mid-infrared.

  6. If this baby gets to L2 and doesn’t work then I’m the first one to volunteer to go fix it. It does have a docking ring after all.

    1. i thought the passive docking ring was removed to save weight. i can’t find any sources less than 7 years old (or that do not refer to documents from 2007) that says it’s still on the JWST.

  7. I’ve got a great idea. There is one place on Earth big enough to test the ENTIRE JSWT with sunshield in thermal vacuum conditions. NASA Plum Brook Station, SPF chamber. Why isn’t the JWST program looking for a full scale test before flight? Wouldn’t that sort out these types of issues?

    1. The SPF chamber at NASA’s Plum Brook Station was investigated early in the program and rejected for logistic and cost reasons. Although several existing test facility options were examined, there is no way to perform a full-scale thermal vacuum simulation of the entire vehicle without building a new chamber,

      1. Only logistical issue I’m aware of is access would need on site runway for air transport. Estimated cost $40M (or $0.005B). Current JWST program $8B. Half of 1% of program cost to provide final full scale test for a one shot no repair flagship mission. Unless I’m missing something that sounds like a good common sense investment

        1. Only logistical issue I’m aware of is access would need on site runway for air transport.

          There were other issues (such as emergency power and instrumentation), although not on the order of building a runway for the one-time landing of a C-5, all of which could be overcome by money. But at the time of the decision, JWST was only a 1 to 2 billion dollar program, and the investment in Plum Brook Station was considered too huge and politically dead.

          Even if the money was found and the testing had proceeded at the SPF, it would not have been a complete simulation since I don’t think you can get the whole thing positioned with the mirror cup up or down (for optical tests) and still have room in the chamber for the deployed sunshield.

          1. Given SPF’s dimensions–122′ high by100′ in diameter–it would be very difficult, if not impossible–to get a support structure in to hold JWST at the right orientation and to get a sufficiently folded optical path and beam size (in order to properly optically characterize the fully deployed mirror), along with the associated equipment, in SPF. It’s quite likely that would have required some very expensive, custom optics. Adding the testing of deployment to that would, I think, have moved the feasibility of such a test firmly into the range of the impossible.

          2. Plum Brook has tested other very large structures in SPF, including ISS radiators. Only 36 engineering changes to get what worked fine in earth conditions to properly deploy in space conditions.

            SPF is easily the world’s largest thermal vacuum chamber — twice the size of JSC’s Chamber A. Would you rather rely on lots of smaller tests to certify JWST, or just a few (or one)? Remember, the sum of the interfaces defines what bites you in the rear end.

            $40M for a runway + actual JSWT SPF tests is a lot less than $8B JWST. While the best counter argument to additional testing is the cost of delaying the launch, the question to NASA is: Can you afford what happens if JWST doesn’t work? At least the sunshield, which can fit in SPF, ought to be tested in thermal vacuum.

          3. At least the sunshield, which can fit in SPF, ought to be tested in thermal vacuum.

            The sunshield is basically a mechanical device.

            What do you think the full scale thermal vac test would show that individual piecepart thermal vac tests or full-scale testing in atmosphere would not?

          4. Plum Brook has tested other very large
            structures in SPF, including ISS radiators.
            Only 36 engineering changes to get what worked fine in earth conditions to
            properly deploy in space conditions.

            SPF is easily the world’s largest thermal vacuum chamber — twice the size of JSC’s Chamber A. Would you rather rely on lots of smaller tests to certify JWST, or just a few
            (or one)? Remember, the sum of the interfaces
            defines what bites you in the rear end.

            $40M for a runway + actual JSWT SPF tests is a lot less than $8B JWST. While the best counter argument to additional testing is the cost of delaying the launch, the question to NASA is: Can you afford what happens if JWST doesn’t work? At least the sunshield, which can fit in SPF, ought to be tested in thermal vacuum.

  9. I’m convinced that our future in space is predicated not in massively expensive and destination oriented projects, but by the development of countless small technologies solving a myriad of problems, some unknown. That’s why I support the design and testing of this solar shade, albeit at enormous expense.

    Space tugs, ways to clean up the junk in earth orbit, tech to move asteroids, and yes, 3D printing are all essential, as essential as a very much cheaper way in and out of orbit.

    Human life will be centered on earth for centuries with space providing a supporting role, possibly by contributing raw materials from asteroids (I’m out on a limb, here, I know). A true civilization in space, if it comes, is a very long way in the future.

    I sense, though, that a rational plan for space is out of the question. We are a curiously odd species, aren’t we? A rational plan that would layout even a vague way forward is impossible- we would squabble so much among ourselves that we would end up paying billions of dollars to shade a damn telescope.

    I offer as proof and at the risk of political disapprobation our lack of a sane energy policy that would take us away from oil and coal over time, thereby ameliorating global warming and, incidentally, removing the rationale for countless resentful citizens in the Middle East. We all know this is plainly needed. Where is this plan?

    For reasons far too disparate to list here, the future of humanity must include a strong space presence. Where is the vaguest hint of how to achieve it? Who is doing the thinking about this?

  10. Sorry, but there is nothing out there worth spending $8 Billion dollars on one piece of hardware. We already have thousands of pictures of places we can see but will never go to.
    But that’s ok, if that $8 Billion dollar piece of hardware fails out there at L2 there’s no fear because not a single NASA head will roll.

    1. How do you conclude that the pictures we have of “places we can see but will never go” are sufficient? I hope realize there are many questions yet unanswered in physics and other sciences that can only be answered by looking outward. JWST’s price did get out of control, but it’s still an impressive instrument that will be able to contribute to some equally impressive science. Don’t conflate the technical merits of JWST with the management problems that were rife within the program.

    2. more has been spent on the Hubble.

      cost at launch: 1.5 billion
      5 repair / servicing missions at ~1.5 billion each = 7.5 billion
      annual operating costs of ~100 million dollars for 24 years (and counting) = 2.4 billion

      estimated total of 11.4 billion.

      1. Probably similar operating cost for Webb so overall similar in cost, assuming no failures.

      2. I think some trade studies were done which suggested that it would have been cheaper to build and launch a new Hubble rather than do the repair missions.
        But they needed the publicity for shuttle and astronauts alike and it seemed like risk didn’t in the end, matter. If there’d been a problem with heat shield or similar it was all over as there was no way to get it to say the ISS.
        Cheers.

      3. I don’t know that you can call the costs ‘similar’. Guess it’s all perspective.
        JWST has apparently cost about $8 billion now. Another say 4 years to launch, what’s that worth, say $2 billion so that’s $10 billion and then operating costs will be higher than Hubble – it’s more complex, more people, larger team particularly initially. It’s going to be lots more expensive just based on historical evidence for NASA projects.
        What else could have been done with say $10 billiion over say 10 years?
        Guess that’s the rub when you look at NASA projects that go well over budget and schedule. The opportunity cost.
        PS. I think you’re right. I couldn’t locate anything on the docking ring. All the info’ says not servicable therefore why need a docking ring..
        Cheers.

        1. the current $8.835 billion estimate for JWST is for its total lifetime cost, according to NASA’s JWST FAQ

          http://jwst.nasa.gov/faq_sc…

          Yeah, I can’t locate anything recent on the docking ring, nor have I found any recent renderings that show it… but I can’t be certain of its fate…

          1. Ok HD, thanks for that information. It’s still been a lot of dough though isn’t it! With flat budgets, NASA’s and their science partners just gotta find a way in which to do science without the huge expense.
            Cheers.

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