[HN Gopher] The James Webb Space Telescope has passed the final ...
___________________________________________________________________
The James Webb Space Telescope has passed the final mission
analysis review
Author : guerrilla
Score : 252 points
Date : 2021-07-07 17:26 UTC (5 hours ago)
(HTM) web link (www.asc-csa.gc.ca)
(TXT) w3m dump (www.asc-csa.gc.ca)
| thangalin wrote:
| Time-lapse video of it opening (~1:20):
|
| https://www.bbc.com/news/science-environment-57078657
| sghiassy wrote:
| OMFG!!!! I'm so excited... let's go!!!!!!!
| cromwellian wrote:
| I feel like this is an all-eggs-in-one-basket mission. If it
| fails to launch, we have nothing.
|
| Why not build many JWSTs, surely the cost per unit would go down,
| and launch more than one?
| chorsestudios wrote:
| The cost per unit would probably remain around the same. You
| don't really get price cuts for ordering 2 of a custom
| component instead of 1
| wolverine876 wrote:
| > surely the cost per unit would go down, and launch more than
| one?
|
| Surely? They didn't build a JWST factory. It might go up, as
| people with specialized skills or knowledge have moved on.
| dgrant wrote:
| I think the verb tenses were not perfect... I think he just
| meant: why did they build only 1 in the first place? They
| could have built N instead, at a lower cost per unit.
| cromwellian wrote:
| Yes, surely. Most of the cost was in R&D and in the mirror
| manufacturing. They've been designing and manufacturing it
| for 20 years. Per-unit costs would go down. Take the mirror,
| it's made of segments, the facility used to produce those
| segments certainly would benefit from scaling up production.
| They'd get better at fabbing them over time, increasing
| yields, reducing costs.
|
| What NASA is doing is building the equivalent of a $10
| billion fab to produce one chip. Space telescopes could be
| continually produced on a schedule, and retired on a
| schedule, with constant improvement.
|
| Look at RS-25 engines vs Raptor engines in terms of costs to
| produce one.
| wolverine876 wrote:
| Increasing production from 1 unit to 2 doesn't necessarily
| reduce costs. Due to demand and limited supply, for
| example, some prices increase. We know almost nothing about
| this thing. It's very speculative to say the cost would
| decrease. Also, how many space telescopes of this variety
| do we need?
|
| All that said, it would be interesting to see NASA research
| on mass producing the more common components of its
| 'product line'. It does it for rockets, of course, but
| computers? Solar panels? Mars rover components? I'm sure
| it's been considered and I expect it's done in ways I'm not
| aware of.
| bumby wrote:
| Certainly a lot of the cost of the project is R&D, but most
| people would be shocked by how much of aerospace project
| budgets are driven by quality. E.g., a bolt costs $200 not
| because it has to go through a new R&D cycle, but because
| it needs a chain-of-custody, inspections, metal coupons
| stored, etc.
|
| There's also a huge amount of political risk for a
| government entity. Politicians will be reluctant to fund
| another JWST if the first one fails because many will fight
| it as a waste of money, and the previous failure just
| bolsters the JWST-opponent's position.
| cnlevy wrote:
| Looks like it just gave Elon Musk some ideas
|
| https://www.reddit.com/r/spacex/comments/ofqm8o/elon_musk_us...
| tectonic wrote:
| Such an exciting, and high stakes, and dramatically late and
| over-budget mission.
| Goety wrote:
| I am so amped for this telescope. I hope it exceeds my
| expectations.
|
| It also looks like this location will be quite crowded in the
| future
| https://en.wikipedia.org/wiki/List_of_objects_at_Lagrange_po...
| sitkack wrote:
| We really should have a big science lab up at L2
| tomschlick wrote:
| Government red tape and contracting at its finest
|
| Edit: Downvotes with no comments as to why... This thing is 24
| years in development and 20x over budget. If thats not a
| failure of government contracting, budgeting, etc then idk what
| is:
| https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Cos...
| - Obviously the platform will be cool once they get it
| launched, but until then its just a money pit.
| DubiousPusher wrote:
| It's because this is a flippant, unhelpful attitude. If we
| were talking about building a mile of blacktop highway then
| such a casual observation about the overrun might be
| warranted.
|
| But we're not talking about that. We're talking about
| building the first non-orbital space telescope in human
| history. To a certain extent, no one could know the actual
| cost ahead of time. It's one of those things you kind of have
| to do and it will cost what it will cost.
|
| Was there waste I this project? Probably. But there's a good
| chance the overruns are dominated by true "found work" rather
| than waste.
|
| In fact, this is exactly the kind of project you want handled
| by the government because the cost of failure is so high. In
| a project where you need to push the risk out as many decimal
| places as possible it is good to have an agency which can
| afford the overruns to do it.
| perihelions wrote:
| _" the first non-orbital space telescope"_
|
| There've been a few others, including Gaia (SEL-2 halo
| orbit -- same as JWST), and Kepler (heliocentric). [edit]:
| also Herschel (SEL-2)
|
| https://en.wikipedia.org/wiki/Gaia_(spacecraft)#Launch_and_
| o...
|
| https://en.wikipedia.org/wiki/Kepler_space_telescope#Orbit_
| a...
|
| https://en.wikipedia.org/wiki/Herschel_Space_Observatory#La
| u...
| DubiousPusher wrote:
| Interesting. I assumed these were in orbit like other
| satellites. I didn't realize they operated from the
| Lagrange points. Thanks.
| omgwtfbyobbq wrote:
| I think you're getting downvoted because what you're saying
| doesn't match up with the wiki article you linked.
|
| The original estimate was for $1.6 billion, in I'm guessing
| the 90s, and the estimate had been updated to $5 billion by
| the time it was formally confirmed for construction.
|
| > The telescope was originally estimated to cost US$1.6
| billion,[102] but the cost estimate grew throughout the early
| development and had reached about US$5 billion by the time
| the mission was formally confirmed for construction start in
| 2008.
|
| So yes, it has been over budget, but by 2x-3x, not 20x, and
| that isn't adjusted for inflation.
|
| Also, everything is just a money pit until it's
| launched/finished/etc.
| tomschlick wrote:
| According to the budget table, when the project started in
| 1997, the budget plan was 500 million. Today its close to
| 10 billion.
| omgwtfbyobbq wrote:
| That was just a bare bones estimate and likely closer to
| the costs of initiating the project than the full cost of
| launching a satellite.
|
| Based on this link, NASA hadn't even settled on a
| design/contractor in 1998.
|
| https://esahubble.org/images/opo9820a/
| guerrilla wrote:
| Adjusted for inflation it'd be about $2.5 billion this
| year. So it's almost exactly 2x.
| wolverine876 wrote:
| What basis do you have for blaming government contracting?
| Lots of projects built by lots of organizations are very late
| and over-budget. One difference between government and
| private industry is that the government has the resources and
| motivation to persist - they aren't in it for profit. If this
| was a private company, it may have been canceled long ago as
| unprofitable. Is that a preferable outcome?
|
| In fact, wasn't the JWST built by Northrop Grumman to a great
| extent? Why not blame them?
|
| EDIT: It's hard to criticize government contracting in the
| same context as NASA, which has taken more risks and achieved
| new things far beyond any private organization in history.
| NASA has operations throughout the Solar System, and in
| interstellar space. They are the only organization to put
| humans on the moon - 50 years ago! Can anyone else say
| anything that? SpaceX?
| minikites wrote:
| Where are all of the privately funded space telescopes?
| sp332 wrote:
| Pointed at earth.
| gamblor956 wrote:
| The original budget was a guess. They didn't know how much
| the telescope would cost because the required technology
| didn't actually exist at the start of the budgeting process
| 24 years ago.
|
| Now that technology does exist, and it turns out it's quite
| expensive, which drove most of the cost increases. However,
| since then the budget increases have generally paced with
| inflation.
|
| Source: your citation.
| DubiousPusher wrote:
| Further to your point, now that the pioneering work has
| been done, a similar piece of equipment could likely be
| built at a significantly reduced cost.
| systemvoltage wrote:
| Another way to put it is that it's a jobs program.
|
| Edit: what's with the downvotes? I would like to understand
| what the disagreement is here. Any gov program can be split
| up into two parts. One, the actual cost as dictated by the
| market economy, and second, the additional costs for delays,
| bureaucracy, etc which usually tends to be multiples of the
| actual costs. This money goes into paying salaries without
| actually making any progress. Hence the jobs program. What's
| there to disagree here? Is this argument somehow belonging to
| a particular political spectrum? Downvotes are fine but I'd
| like to gain some understanding of where my thoughts are not
| aligned with you. Please explain your position.
| DubiousPusher wrote:
| By that logic, so is the military, public schools and
| highway maintenance.
| systemvoltage wrote:
| Any over budget and poorly run government program I see
| it as a jobs program. F-35, CalTrain, NASA SLS, etc.
|
| This is in stark contrast with partnerships with private
| industries. For eg DARPA + Moderna or NASA + SpaceX.
| DubiousPusher wrote:
| I fail to see the difference. Private contracts often go
| over budget. The F-35 itself is full of privately
| contracted parts. Many public/private partnerships
| contracts are even no bid, meaning they are essentially
| uncompetitive. Whether the government hires people
| directly to do a job or whether they contract it out is
| equally distortionary. By allocating tax dollars to a
| public rocket lab or to a private rocket company you are
| increasing the demand for rocket engineers and thus
| creating a "rocket engineer" jobs program.
| wolverine876 wrote:
| All those projects were built by private industry,
| including the latter two.
| systemvoltage wrote:
| That's true. I concede my point.
| bumby wrote:
| While I am as critical of government overspending as
| anyone, this comparison misses some important nuances.
|
| Let's take the SpaceX example. SpaceX is great in terms
| of pushing innovation. But there would be no SpaceX
| without NASA or other government entities. They need
| those tax dollars (especially early on) to survive. And
| when they lose a government payload, the government takes
| something to the tune of 80% of the loss because they are
| self-insured. This has the effect of SpaceX farming out
| their risk to the government.
|
| But this is one of the areas where the government excels.
| Namely, taking large risks in nascent fields where the
| risk is too big for private companies to balance against
| the benefit by themselves. But the complexities and
| unknowns that create that risk is also the very same
| thing that creates the budget and schedule risk as well.
| Lammy wrote:
| I would say "PR program" more than jobs program. NASA is
| the public face of the DoD/NRO spy satellite tech. Most of
| them are just looking back toward Earth at you and I
| instead of looking out into space. Compare to these
| programs which had over 4x the budget of JWST in 2004:
| https://en.wikipedia.org/wiki/Key_Hole
|
| e: For example, KH-11 shares parts with the Hubble Space
| Telescope: https://en.wikipedia.org/wiki/KH-11_Kennen
|
| 'KH-11s are believed to resemble the Hubble Space Telescope
| in size and shape, as the satellites were shipped in
| similar containers. Their length is believed to be 19.5
| meters, with a diameter of up to 3 meters.[5][23] A NASA
| history of the Hubble,[24] in discussing the reasons for
| switching from a 3-meter main mirror to a 2.4-meter design,
| states: "In addition, changing to a 2.4-meter mirror would
| lessen fabrication costs by using manufacturing
| technologies developed for military spy satellites.'
|
| Notice how that says KH-11 _s_ , plural.
| ufmace wrote:
| The thing with this kind of project, we're not punching out
| the 10 millionth Honda Civic or something. There's a
| tremendous amount of stuff here that's never been done
| before. There's no good way to have an accurate estimate for
| how much it will cost. You pretty much have to just keep
| spending until you get it right. This works the same way
| whether it's Government or Private Industry. Just ask Intel
| how far over budget they've gone getting EUV working.
| systemvoltage wrote:
| It blows my mind that humans can get together and build
| something like this.
|
| I was just watching YT channel "Primitive Technology" and it
| really puts things into perspective. From sticks and stones to
| bootstrapping a James Webb Telescope that's gonna sit at a
| langrange point between the Earth and the Sun. Woah.
| swader999 wrote:
| Interesting angle and this telescope really is a time
| machine.
| slownews45 wrote:
| Does anyone remember the initial proposals for this. The cost was
| supposed to be $500M. At most something like $1B.
|
| Given this is standard govt contracting - I'm sure it's come out
| much higher.
| ProAm wrote:
| Wait until you see what they claimed the Iraq and Afghanistan
| wars were supposed to cost....
| Jabbles wrote:
| Here is a nice table with the history of the budget:
|
| https://en.wikipedia.org/wiki/James_Webb_Space_Telescope#Cos...
| slownews45 wrote:
| Clicking through we get this
|
| "JWST is now estimated to cost approximately $9.7 billion and
| launch in October 2021, which represents cost growth of 95
| percent and 88 months of schedule delays since the project's
| cost and schedule baselines were first established in 2009."
|
| So around $10B. Amazing.
| elihu wrote:
| I wonder what the marginal cost would be to build a second
| one?
| swarnie_ wrote:
| Fact boy covered it a few weeks ago:
|
| https://www.youtube.com/watch?v=CowU0QK0Pjs&ab_channel=Megap...
|
| From what i remember this project has been running since around
| the time of Hubble
|
| Still.... Can't wait for it to get up there, money and time
| well spent!
| slownews45 wrote:
| That's pretty amazing. A financial black hole.
|
| A cool project, but if you think of the thousands of folks
| who didn't get funding so this thing could gobble everything
| up - these projects really become crazy budget wise (SLS did
| the same path).
|
| I wish they would do pay for performance deals. We'll give
| you $4B if you put a telescope in space of X size that meets
| some basic specs.
|
| If you look at commercial side, space imaging (earth facing)
| has just exploded and the cost side has gotten very very
| good. So it's clear you can get optics and sensing into space
| for a lot less.
| swarnie_ wrote:
| 10bn in the scope of this joint project between the US,
| Europe and one other group (Canada or Japan?) is a rounding
| error over 20 years.
| nickik wrote:
| $1B? That gone last a year tops.
| OrvalWintermute wrote:
| Even 5B for a novel, and uniquely powerful observation platform
| would be a bargain!
|
| When you are engineering a unit of 1 pushing the boundaries of
| science, with multiple conflicting constraints, funded by a
| variety of self-interested stakeholders, and are forced to do
| commercial production, rather than govt production, even when
| it is most cost effective, it isn't like you are heading
| towards lowest cost, technically acceptable.
| slownews45 wrote:
| You can get a pretty good idea of quality of project
| management based on how well or poorly they estimated project
| baseline costs at outset.
|
| These are linked - incompetence in estimating costs /
| complexity = incompetence in execution = insane cost
| overruns.
|
| And you would get far more science with 5 $2B projects then
| one project like this. And if this thing has a launch of
| deployment problem all eggs in one basket. If there are cost
| overruns and delays, also all eggs in a basket and no other
| options.
| marcusverus wrote:
| It's easy to throw these big numbers around, but do you ever
| stop to consider the actual cost? Let's do some back-of-the
| envelope calculations to help us consider the human cost of a
| 5B telescope.
|
| The Median US household income is ~68,000/year[0] The Average
| income tax paid by someone in the 50-75K income range is
| $4,600/year.[1] The average working career is probably around
| 40 years.
|
| 5,000,000,000 / 4,600 / 40 = 27,173
|
| To fund a $5B project, 27,173 people (more, actually, since
| this is household data) could have worked _for their entire
| working lives_ , with every dime of federal income tax being
| spent on that one project!
|
| I agree that the JWST is a worthwhile project, but let's not
| pretend that it's a bargain.
|
| [0]https://www.census.gov/library/publications/2020/demo/p60-
| 27... [1]https://www.fool.com/taxes/how-much-does-the-
| average-america...
| lapetitejort wrote:
| Using the same numbers, 3,824,456 people worked their
| entire lives to fund the USA's military for 2021.
|
| https://www.defense.gov/Newsroom/Releases/Release/Article/2
| 6...
| RaiausderDose wrote:
| please don't blow up and deploy successful in space
| canadianfella wrote:
| Punctuation has a purpose.
| sonograph wrote:
| I remember getting excited about this telescope a decade ago. I
| haven't heard of it since; but I thought it's budget was cut and
| it was over.
|
| I'm excited NASA is finally going to get it up in space!
| darkwater wrote:
| It's ESA that's getting it up into space, NASA is "just"
| collaborating.
| sp332 wrote:
| https://xkcd.com/2014/
| pkaye wrote:
| Actually the budget was overrun quite a bit. I think it will
| cost $10B at this point.
| keanebean86 wrote:
| $9.5 billion over is pocket change! If you adjust for
| inflation $10 billion is only $7.7 billion in 2007 dollars.
| Assuming the telescope works I can live with it being
| expensive.
| mtdewcmu wrote:
| Unlike the F-35, I think the taxpayers are getting their
| money's worth.
| bumby wrote:
| Unfortunately, I think it's easier to fund something like
| the F-35 because it can be framed as a way to avoid an
| existential threat. It's difficult to do the same with
| fundamental science
| abz10 wrote:
| The F-35 was framed as a way to save money.
| bumby wrote:
| That argument only holds because it was purported to
| replace different weapons systems that were needed for
| mitigating a threat. The threat is the primary motivation
| and cost reduction is secondary. I.e., if not but for the
| existential threat there's no need for the JSF or any
| system it would replace.
| abz10 wrote:
| The F-22 was sufficient for threat mitigation. The F-35
| raison d'etre was cost reduction, after that was
| exportability which again was supposed to help with cost
| reduction.
|
| Edit; comparing the logic of a 'but for' vs a 'necessary'
| condition. Was the F-35 necessary for threat mitigation.
| No. Was it framed as the necessary for cost savings, yes.
| Retric wrote:
| Their designed for slightly different roles. The F-35's
| R&D looks hard to justify vs simply having more F-22, but
| the F-35B can do verticals takeoff for example and the
| F-22 can't.
|
| So, the real question is if the F-35's should have had
| fewer versions and thus been more capable in it's
| remaining roles.
| bumby wrote:
| There's similar analogies here to the space shuttle.
|
| For the shuttle to get approved, it had to meet the
| demands of many masters. The fact that it had to meet DoD
| missions as well as NASA missions made it a bit of a
| boondoggle. Likewise, the JSF needed to meet the Marine
| Corps demands of VTOL to take the place of the AV8B.
|
| It's hard to remain focused when you have so many
| stakeholders. As the saying goes, a camel is a horse
| designed by committee.
| GekkePrutser wrote:
| The space shuttle wasn't as bad as its reputation though.
| Both accidents had organizational causes and were
| entirely avoidable. And its huge payload bay and the fact
| it was a mobile base allowed for the construction of the
| ISS.
|
| It just failed at reusability, it was more like
| refurbishability :) But many lessons have been learned
| from that.
| bumby wrote:
| > _Was the F-35 necessary for threat mitigation. No. Was
| it framed as the necessary for cost savings, yes._
|
| I think we're saying the same thing. The argument is,
| "Was the F22/F18/Fwhatever/weapon-system necessary for
| threat mitigation? Yes."
|
| With that said, if proponents of the F35 want to frame it
| as "threat reduction + cost savings" that's how they get
| the budget approved. But the point stands that without a
| threat, there's no basis for the cost savings argument.
| I'm not saying it was effective as cost reduction.
|
| To circle back to the original point, it's much easier to
| get a budget approved when the basis is existential
| threat, rather than "science is cool."
| abz10 wrote:
| I don't think it's a great example of using existential
| threat for sales, when the whole thing was sold as a cost
| saving. Pretty much everyone at the time just wanted more
| F-22s.
| justshowpost wrote:
| Yes, if you prefer eye candy photos to public safety. By
| the way will James Webb wield a modern eye candy capable
| sensor? Not sure about that.
|
| There is few worth from remote sensing unreachable (even
| in theory) objects. Kepler already proved theoretized
| Goldilocks Zone rocky planets and, in general, provided a
| lot of data for non-field research (less exciting than
| Hubble photos indeed). Last, but not least, what's the
| JWST's mission exactly?
|
| Also, from taxpayers' money perspective Kepler's
| component quality was complete disaster.
|
| So, I'd better invest in more Martian/Jovian probes than
| in revival of obsoleted project. Such revival is very
| similar to Russian GLONASS (a competitor to 1970s
| NAVSTAR) programme reboot.
| eganist wrote:
| I hate how shortsighted these comments tend to be, but I
| can understand them.
|
| The money for projects like this, largely due to the
| sensitive nature of it all, still ends up staying local
| to the governments funding the projects, which means a
| significant minority of it still gets recouped in taxes
| two or three degrees down, and the balance that can't be
| recouped still ends up funding colossal technological
| advances, e.g advances in EM sensors, lensing, computing,
| electronic resiliency, power generation, the list goes
| on.
|
| The reason governments spend on projects like this
| regardless of public opinion is because they're necessary
| to advance the state of science and engineeeing when
| investment returns are out of the question near-term.
|
| Even defense spending operates this way, though the
| degree to which we pour good money after bad in defense
| is probably worth scrutiny. At least JWST will bring
| value, unlike the f35.
| whatshisface wrote:
| The JWST's mission is to see deep infared, which can pass
| through interstellar clouds. It will uncover things that
| have been veiled to us since the beginning of history. It
| can only be built as a space telescope because the
| frequency of its intended observations are so low that to
| a device sensitive to them, air radiates light of
| blinding intensity.
| RapidFire wrote:
| Thanks for this comment; that's a fascinating bit of
| information.
| sawjet wrote:
| All those European tax payers are certainly getting their
| money's worth
| callesgg wrote:
| I bet it will fail to deploy properly. But I hope not.
| [deleted]
| abhiminator wrote:
| On a related note, I highly, highly recommend watching this well-
| made documentary on JWST, released around 3 and a half years ago
| -- https://www.youtube.com/watch?v=FLD9LKq0u9E
|
| This documentary was produced by Northrop Grumman Corporation --
| the builders of JWST under a NASA contract.
| mongol wrote:
| What is it hoped this can see? Is there some specific hypothesis
| this telescope was built to confirm?
| SiempreViernes wrote:
| Hopefully it'll tell us about the period of reionisation, when
| the light of the first galaxies made the universe transparent
| again.
| redisman wrote:
| The oldest galaxies that have red shifted off the spectrum and
| are only visible with this. You can't do IR telescoping except
| at L2 because earth is giving off its own IR reflection or
| radiation or something like that
| 908B64B197 wrote:
| Here's the official release from the launch partner
| [0](Arianeespace and the Eeuropean Space Agency are providing the
| launch on an Ariane V rocket).
|
| They are the ones responsible for that milestone of the project
| (NASA and JPL already completed manufacturing of the spacecraft).
|
| Exciting news!
|
| https://www.esa.int/Science_Exploration/Space_Science/Webb/W...
| endymi0n wrote:
| While it's awesome to finally see the JWST finally come to close
| to launch after all those years, now it's a close race between it
| and SpaceX Starship that could have taken the 6.5 meter mirror up
| to space in one whole piece in its 9m diameter belly rather than
| having to do all the miraculous origami that took two decades to
| develop in the first place...
| jasonwatkinspdx wrote:
| While I'm rooting for SpaceX with Starship, lets be clear:
| they're still trying to get hovering grain silo versions
| working. Meanwhile JWT is ready to go. If it's a race one side
| has already won rather emphatically.
| wolverine876 wrote:
| SpaceX has nothing to do with this. Their rocket has zero
| demonstrated capability for this mission.
| minikites wrote:
| I wouldn't trust any payload on a SpaceX ship given their track
| record.
| JoeAltmaier wrote:
| That's how space travel development works. It doesn't take
| off; it crashes; it explodes; it fails to land; it works.
| From then on pretty much, it works.
| wolverine876 wrote:
| What is that based on? How do you distinguish launch
| systems that just don't work well? Everything works in the
| end? That would make engineering much easier and less
| stressful!
| jl6 wrote:
| If the JWST survives launch but has a subsequent mechanical
| problem that prevents it deploying properly (and it's the kind of
| problem that would have been fixable on Hubble, using a shuttle
| mission) would it be feasible to mount a robotic rescue mission
| to chase it down and remote-hands it back to life? For less than
| the cost of just launching another JWST?
| OrvalWintermute wrote:
| It is conceivable that on-orbit repair missions like OSAM-1
| could fix a mission with a mechanical failure, depending on the
| orbit that it reaches.
|
| https://nexis.gsfc.nasa.gov/osam-1.html
| derekp7 wrote:
| I would think that a cheaper (or multiple cheaper) versions
| could be made if they don't require the long lifespan and
| reliability that previous launch costs inflicted. Once Starship
| is going, and if it proves to be as low cost as the current
| projections, I could see multiple space telescopes being
| designed cheaply for a launch every year, each one designed in
| a narrow configuration that serves a specific purpose. But I
| really don't know what all goes into making a space telescope
| so expensive currently.
| phkahler wrote:
| >> But I really don't know what all goes into making a space
| telescope so expensive currently.
|
| I think you already said it. The long life (high reliability)
| requirement, and I'll add the complexity of having it unfold.
| Both of those become non-issues if you build the telescope
| right into a space-X starship. There may be other issues with
| that, but the mirror wouldn't need to fold ;-)
| bumby wrote:
| Are you speaking to the reliability of the launch vehicle
| or of the satellite? The launch itself is typically not a
| primary cost driver of a satellite mission. Complexity may
| be, due to constraints of the fairings but the
| manufacturing and quality checks drive quite a bit of the
| cost
| deepsun wrote:
| Also, all robotic space repair satellites are very into
| military tech (even taking pictures of open space is very
| strictly controlled, because you may inadvertently take a
| picture of a military satellite). Not event talking about
| disabling err.. repairing, de-orbiting, spinning etc other
| satellites. That types of tech is opposed by military, that's
| actually one of the reason we don't clear dangerous space
| garbage (especially considering some of that garbage is
| actually working military satellites).
| ufmace wrote:
| The trouble with robotic repair missions is that it could work
| pretty well if you knew 100% exactly what was wrong, and
| exactly what else might go wrong while applying the fix for
| whatever went wrong. The more potential unknowns, the harder it
| is. It's much harder to make a robot with enough general
| flexibility that it could probably handle diagnosing and
| repairing an unknown issue, or handle something going wrong
| while trying to carry out a planned repair sequence. Bolts
| jammed, too loose, too tight, tanks of stuff springing leaks,
| electrical short in some unknown place, component overheating
| for unknown reason, all sorts of things can go wrong that are
| tough to diagnose remotely or with a special-purpose robot.
| nhoughto wrote:
| And you'd need to have it designed to be serviceable once
| deployed. I'd imagine there would be a few assumptions going
| into the design process, "once deployed humans won't ever
| need to get to that.."
| nabla9 wrote:
| The JWST will not orbit Earth. It will be located near the
| second Lagrange point (L2) over 1,500,000 km away (The Moon is
| just 405,000 km from the Earth).
|
| Space Shuttle could not have reached it.
| wyldfire wrote:
| How long can it stay stable at that point? Does it have
| thrusters to keep a station there? If so, how long is the
| fuel for them provisioned for?
|
| Does use of the thrusters impact the sensors that the
| telescope uses?
| pageandrew wrote:
| The orbit needs to be actively maintained. The telescope
| was designed for a 5.5 year mission, but NASA says it could
| last up to 10.5 years with proper fuel management. It has
| two different types of thrusters under the "Propulsion
| Subsystem".
|
| > One kind is called "Secondary Combustion Augmented
| Thrusters" (SCAT), and they are used for orbit correction
| (like applied changes in velocity for each maneuver the
| spacecraft makes and also for orbit station-keeping). The
| SCATs are bi-propellant thrusters, using hydrazine (N2H4)
| and dinitrogen tetroxide (N2O4) as fuel and oxidizer,
| respectively.
|
| > The other kind of thruster on Webb is called a MRE-1, or
| mono-propellant rocket engine, since it only uses
| hydrazine. There are eight MRE-1s on Webb, and they are
| used for attitude control and momentum unloading of the
| reaction wheels
|
| Ref: https://jwst-docs.stsci.edu/jwst-observatory-
| hardware/jwst-s...
| spywaregorilla wrote:
| > Does use of the thrusters impact the sensors that the
| telescope uses?
|
| The point of sitting in a lagrange point is that you can
| stay there without moving due to two gravitational forces.
| That's not perfectly accurate, but I don't think it needs
| constant thrust, just occasional taps.
| [deleted]
| hguant wrote:
| The L2 point is unstable with a period of 23 days? I
| believe, so the JWT needs a course correct burn to stay
| positioned correctly (called station keeping).
|
| It does have thrusters - a ring of 16 hydrazine "burning"
| units that can produce thrust on 3 axis.
|
| The fact that the L2 point is unstable and that thrusters
| are required puts a lifetime on the telescope - I think
| NASA plans for a minimum of 5 1/2 years and are hoping to
| get up to 10. That's entirely reliant on the fuel supply.
|
| The use of thrusters does impact the sensors the telescope
| uses. NASA et al schedule usable telescope time around
| burns, and general attitude shifts/correction. The
| telescope uses a bunch of gyroscopes/flywheels to point
| itself in the proper direction, during maneuvers like that
| the sensors aren't operable.
| pklausler wrote:
| It's not an orbit, per se, but... it will go around the Earth
| once per year.
| phkahler wrote:
| >> it will go around the Earth once per year.
|
| I think more accurately it will go around the sun once per
| year. The earth will provide the extra gravitational pull
| (toward the sun) needed to orbit the sun at a larger radius
| than the earth in the same amount of time as the earth.
| pklausler wrote:
| Sure, but it also goes around the Earth once per year,
| too, sidereally.
| sp332 wrote:
| It equally orbits the sun and the earth.
|
| Normally, objects with smaller orbits take less time to
| make a circuit. But this is placed where the earth's
| gravity pulls it back, just enough to make it take one
| (earth) year to finish its smaller orbit. So gravity from
| the earth and the sun are involved.
| geenew wrote:
| It has a docking clamp, though that's for future-proofing.
| Apparently the initial type of mission envisioned was a crewed
| Orion vehicle, though I'm sure a wide variety of missions
| _could_ attach.
|
| My guess was that the clamp was mainly for possible future
| replenishment of consumables, though presumably some sort of
| robotic-arm-equipped repair mission could attach as well. A
| crewed mission seems possible, too, assuming one of the planned
| Lunar craft could be modified to go to the Lagrange point.
|
| https://www.space.com/3833-nasa-adds-docking-capability-spac...
|
| https://en.wikipedia.org/wiki/Spacecraft_Bus_(JWST)#Docking_...
| imglorp wrote:
| Nothing in the current fleet of new capsules have arms or
| airlocks.
|
| There is hope for the robotic refueling type mission though,
| or at least the kind where a new utility bot attaches to an
| old satellite and takes over propulsion to extend its life.
|
| https://nexis.gsfc.nasa.gov/rrm_refueling_task.html
| Torkel wrote:
| Latency is a bitch. So remote hands from earth is most likely a
| no-go, for this reason alone.
|
| And if you bring astronauts close, then I guess that some EVAs
| in existing suits starts looking appealing vs developing those
| remote hands.
| system2 wrote:
| They wouldn't operating it like they play computer games.
| Mars rover has a major latency too, they can simply instruct
| it with limits and work slightly slower.
| BitwiseFool wrote:
| The JWST orbits out beyond the Moon, so I don't know if the
| Orion capsule and European Service Module even has the Delta-V
| to make it to that Lagrange point and back. Plus, I'm also
| unsure about the life support and duration requirements for
| such a mission.
|
| I imagine the only realistic repair mission would be with a
| Starship crew, seeing as Orion and all the other Commercial
| Crew vehicles would probably require some additional components
| to make it out that far and to sustain their crews. Starship
| seems big enough and far enough along in development to be
| viable.
|
| Edit: The JWST has a docking ring to let Orion service it. But
| I don't know if the SLS in it's available configurations can
| get it up there. It _seems_ like a contingency but I don 't see
| any solid information about an Orion service mission.
| wolverine876 wrote:
| The GP asked about robotic, not human missions.
| BitwiseFool wrote:
| My mind skipped over that. I don't have a good answer for a
| robotic mission but I imagine NASA won't fund it.
| ultramegachurch wrote:
| Highly unlikely. That would require designing a new spacecraft
| from the ground up while also developing new robotics and
| operations technologies. I'd peg that mission at $300 - $500
| million. NASA would almost certainty be better off documenting
| lessons learned and pursuing a new observatory.
| nrdgrrrl wrote:
| They've spent almost 10 billion dollars on this telescope so
| far. What's another 0.5 billion for a repair mission?
| mcbutterbunz wrote:
| > I'd peg that mission at $300 - $500 million.
|
| If that was the cost for that mission, it would be worth it
| considering JWST cost about 20x that amount.
| bl5THJUSFXWy4ii wrote:
| You are considering the entire cost of developing the JWST.
| Surely the cost of building another based on the finished
| design would be lower.
| e_y_ wrote:
| I think part of the reason the JWST took so long to build
| was the complexity of the design. As in, it was difficult
| to manufacture and assemble and test due to the way it
| was designed. It might be cheaper to do it a second time
| based on the lessons (avoiding mistakes) from the first,
| but it would probably still be quite expensive.
| spaetzleesser wrote:
| When I look at project management for the small projects (1-20
| people) I am working on I always wonder how projects of such a
| complexity are managed. It must be freakishly difficult to
| coordinate all the pieces.
|
| The people working on this will also have several stressful
| months ahead of them. From launch to full deployment so many
| things can go wrong and there is nothing that can be done when
| something fails.
| Ronson wrote:
| I seen a video on this today, (megaprojects) and I thought the
| same thing and wondered how deep it goes.
|
| Like something about the sun shield being the width of a human
| hair, someone put the idea forward, something about how many
| motors are involved in unpacking, someone put the idea forward.
| All the way to the Ariane rocket.
|
| Is for example, the Ariane rocket so good that the person in
| charge is sipping tea and eating biscuits the night before
| launch, or is that person biting their nails to the bone hoping
| that it doesn't go wrong in some way with a 10 billion payload
| on board?
| 0xF57A wrote:
| I was watching a presentation given by the MGT project manager at
| cal tech and he mentioned that the MGT has a lower diffraction
| limit than the JWST. I think "diffraction limit" was the term he
| used, I don't remember. The idea was that the images are supposed
| to be sharper. I was very confused about that. Why build JWST if
| MGT is going to maker cleaner images?
| bronson wrote:
| MGT is limited to the light that filters through the
| atmosphere. JWST will be tuned to longer wavelengths
| (redshifted older objects) that can only be seen in cold space.
| wolverine876 wrote:
| > JWST will be tuned to longer wavelengths (redshifted older
| objects) that can only be seen in cold space.
|
| As I understand it: We're placing it at L2 specifically for
| that reason, to isolate it from other radiation.
| jcims wrote:
| I'm just a rube but in general there are two issues:
|
| 1 - the atmosphere distorts and filters out a lot of light in
| various wavelengths. MGT likely has better resolution, but only
| for light that reaches it.
|
| 2 - JWST is primarily for infrared. Given blackbody radiation
| of the equipment itself can create a bunch of noise there, it's
| important to keep the equipment as cool as possible.
| bongoman37 wrote:
| Many wavelengths of light are simply blocked by the Earth's
| atmosphere. If you want to see them you have to go above the
| atmosphere.
| wthomp wrote:
| The diffraction limit is the fundamental resolution limit of a
| telescope. This is the size of "spot" that will be created on
| the camera sensor for a single point of light like a star [1].
|
| Its easy to calculate, just take the wavelength of the of light
| you want to observe and divide it by the diameter of the
| primary mirror (and multiply by ~1.2).
|
| For example, for JWST observing in the mid-infrared, say
| 4micron, with a 6.5 meter diameter mirror, has a resolution
| limit of: 4e-6 / 6.5 = 6.15e-7 Or about 0.6 micro-radians
| (astronomers would normally use arcseconds but leaving in
| radians for clarity).
|
| This is just the theoretical limit though, it's reduced by any
| imperfections in the optics, and for telescopes on the ground,
| it's limited by the blurring of the Earth's atmosphere to about
| 4 micro-radians.
|
| For narrow fields of view, however, ground-based telescopes can
| use adaptive optics to compensate for this shimmering/blurring
| in real time and reach close to their theoretical diffraction
| limit. Plus, they can be much bigger since we don't have to
| launch them into space. I'm not familiar with the MGT but this
| might be how it will surpass JWST in terms of resolution (which
| again also depends on the wavelength).
|
| For infrared observations though, a huge effect that can't be
| compensated for is sensitivity. At mid-infrared wavelengths,
| the Earth's atmosphere actually glows and makes it much harder
| to see faint sources. This is one of the ways JWST will really
| shine.
|
| [1] Note however that you can still do things like measure the
| position of an object to less than the diffraction limit using
| e.g. centroiding. But you can't tell if there are two objects
| or one below this limit.
| DiogenesKynikos wrote:
| I'll add to this that resolution is not the only metric by
| which you can judge a telescope. One major advantage that
| space telescopes have is that their environment is much more
| stable, making calibration (for example, of the flux of a
| source) easier. On Earth, the weather changes from night to
| night, or even from minute to minute. You're effectively
| looking through a constantly changing, semi-opaque filter -
| the atmosphere.
|
| Ground-based telescopes have their own advantages, like the
| fact that they can be much larger and therefore can collect
| much more light.
|
| This is just to say that both space- and ground-based
| telescopes are useful, and have their own strengths.
| foota wrote:
| I believe there are some kinds of photography that can only be
| done outside the atmosphere.
|
| Edit: see:
| https://en.m.wikipedia.org/wiki/James_Webb_Space_Telescope,
| particularly comparison with other telescopes. Seems the
| primary reason is for infrared photography.
| jjoonathan wrote:
| Maybe MGT isn't limited by diffraction but rather by
| atmospheric distortion (or residual distortion, because
| presumably they do what they can to correct it)? Just a guess,
| I'm not an astronomer.
| fnord77 wrote:
| what's the biggest risk? rocket failure during takeoff or
| telescope malfunction?
| xeromal wrote:
| I believe the unfurling of the solar panels is one of the
| tricky parts.
| FranOntanaya wrote:
| Most rockets these days are pretty reliable. Ariane 5 only had
| one partial failure in 20 years I believe.
| RaiausderDose wrote:
| Ariane 5 rockets have accumulated 109 launches since 1996, 104
| of which were successful, yielding a 95.4% success rate.
| Between April 2003 and December 2017, Ariane 5 flew 82
| consecutive missions without failure, but the rocket suffered a
| partial failure in January 2018
|
| from: https://en.wikipedia.org/wiki/Ariane_5
| topspin wrote:
| There are several big risks. It's impossible to rank them in a
| credible way.
|
| Obviously there are all the usual launch risks. The cryogenics
| system has had a lot of development problems. The deployment is
| staggeringly complex and involves components that are not known
| for their robustness. Finally there is no repair option; one
| critical things goes wrong or is found to be misdesigned and
| that's it.
| abacadaba wrote:
| godspeed jwst team! find me an alienz!
| 1970-01-01 wrote:
| It's pretty close to launch, but it still feels like it's not
| going to be ready for a few more years!
| baggy_trough wrote:
| Going to be amazing if this thing can actually unfurl, but I'm
| scared.
| detritus wrote:
| I don't know why, but I've had this gut-wrenching feeling for a
| couple of years now that Something Terrible is going to happen
| to this before it gets into position at L2.
|
| I really hope not, obviously, but this seems like an All Your
| Eggs In One Basket lesson in the making.
|
| We need to commodify this tech, make them somewhat disposable,
| and sent oodles of them up on Starships.
| cnlevy wrote:
| Using 3 COTS (Commercial Off The Shelf) components with 90%
| reliability can ensure 99.9% redundancy instead of having a
| Unique _very reliable and even costlier_ 99.9% custom
| component can really lower costs. But it can happen only if
| mass is not a constraint.
|
| From Casey Handmer's blog:
| https://caseyhandmer.wordpress.com/2021/03/04/sls-what-now/
|
| The Perseverance Mars rover cost $2.4 billion, which works
| out to a few thousand salaries for just under a decade.
| Thousands of people are needed to build this rover because
| landing stuff on Mars is so hard that subsystem masses must
| be tracked to a tenth of a gram, on a system that weighs a
| tonne. The whole thing is meticulously handcrafted from
| custom silicon, PCBs, titanium tubes, motors, cameras, and
| other awe-inspiring instruments. Starship will be able to
| land 100 of them per flight. Now what? How can NASA feed a
| team that makes one feather light rover per decade for a
| billion dollars if the demand just jumped by a factor of a
| thousand and the unit cost fell by the same amount? Set up a
| production line? Work out how to make them with a team of
| ten? Build one every two weeks?
| CamperBob2 wrote:
| They should put that team to work on next-generation tech,
| the stuff that's not yet a commodity. They can start
| working on habitat construction materials and hardware, for
| instance.
|
| Although it is interesting to consider that we've put a lot
| of expense into optimizing payloads that, in retrospect,
| would have been smarter to put into better launch vehicles.
| SpaceX probably isn't going to spend $2 billion developing
| Starship (even if Boeing would have.)
| meepmorp wrote:
| IIRC, SpaceX is getting $2.89B from NASA for the Artemis
| lander, which proposal is based on Starship. Although,
| the GAO put that on hold recently, after complaints from
| BlueOrigin and Dynetics. Hardly surprising, I guess.
| pkaye wrote:
| The material requirements are extreme to what we typically us
| on earth. Handling temperature extremes, radiation, low
| outgassing, low weight.
| detritus wrote:
| We Can Do This(tm)
|
| - ed. For clarification, I imagine that I personally can't,
| so instead:
|
| It Can Be Done(tm)
| tleilaxu wrote:
| Same feelings here!
|
| Ever since it was announced I have been anxious about it all
| going to plan.
|
| Sometimes I put myself in the shoes of the engineers and
| controllers, and I can't imagine how nerve wracking it must be,
| waiting and waiting!
|
| The thing could simply blow up on the launch pad, for goodness
| sake!
| piquadrat wrote:
| Arianespace fat-fingering an Ariane 5 into the wrong orbit
| recently didn't exactly help with my anxiety...
|
| https://spacenews.com/bad-coordinates-led-ariane-5-astray-
| la...
|
| (OTOH, I'm positive that particular issue won't reoccur)
| holler wrote:
| > The thing could simply blow up on the launch pad, for
| goodness sake!
|
| exactly, I've wondered why they don't build e.g. 2 or 3 of
| them in tandem since it'd likely be cheaper/easier to do up
| front vs after the fact if things went wrong. They would then
| have the additional telescopes if things went right, offering
| even greater access.
| AnimalMuppet wrote:
| With Mars landers, they _do_ build two of them. When they
| have an issue with the one on Mars, they break out the one
| here on Earth and start debugging. When they have a
| solution that works, then they know what to do with the one
| on Mars.
|
| I don't know if that would work on telescopes, though - I
| suspect that the copy wouldn't have the full optics
| installed.
| OrvalWintermute wrote:
| You're correct - building constellations is definitely much
| cheaper.
|
| For an observational/capability platform such as for DoD or
| NOAA, making a large number in a series makes sense. For a
| research platform (NASA/NSF) that same idea doesn't apply,
| since science objectives dominate the discussion.
| lisper wrote:
| I used to work at JPL, and I was there when the sky-crane (the
| system currently used to land rovers on Mars) was first
| proposed back in the late 90s. I remember thinking to myself,
| "That is the craziest idea I have ever heard, there is no way
| that could possibly work." But it did.
|
| Never bet against NASA engineers. Sure, they have the odd high-
| profile screwup, but on the whole they are shockingly
| competent.
| jcims wrote:
| Do you know if there is any test footage of that anywhere?
| That's, to me anyway, the second most amazing thing about the
| sky crane...that I can't find a single frame of it in
| operation on earth.
| lisper wrote:
| Sorry I have no idea.
| bpodgursky wrote:
| I almost want the unfurling to get stuck, just b/c SpaceX
| launching a manned Starship out to a LaGrange point to hotfix
| it would be super cool.
| bronson wrote:
| Fly out there, spacewalk over, give it a little jiggle, looks
| good, fly home.
|
| It would be like driving six hours to push a power button,
| but epic.
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