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I'm just a space nerd, all the below is conjecture. Lots of talk about refueling even with the 20 year lifespan, from what I've gathered having watched a lot o

I'm just a space nerd, all the below is conjecture. Lots of talk about refueling even with the 20 year lifespan, from what I've gathered having watched a lot of the NASA conferences and livestreams this past year, with this amount of operational fuel capacity the problem in 20 years will be on operational lifetime of wear components, not just the fuel. The reaction wheels are _large_ moving parts on the JWST. The cryocooler for the MIRI is a very finely calibrated moving part. It's a closed system, but still relies on pumps and electronics. After 2 decades of operation it's very likely that these will be experiencing some issues. While in 2 decades it might be feasible to refuel the JWST, it seems very unlikely it'd be worth it given the operational wear of every other component. Had we used too much fuel to correct the course to get where we are the math may have been very different. Seems to me that we're fortunate that we can instead dedicate resources to the next-gen observatories!

samwillis 5y ago
With SpaceX Starship the space industry is going to be very different in 20 years time. Launching new telescopes, even larger ones, will be much easer. Attempts to refuel will be completely unneeded. Edit: This seems to be a controversial opinion (based on down votes). To clarify, my expectation is that if launch costs have come down as much as people suggest, launching a new and improved (potentially significantly larger) space telescope would be a better use of funds than a complicated and risky refuelling mission. There will be many lessons learnt from JWST that by then there will be an appetite for something new. My hope also is that if the cost to launch has come down so would the development costs of any new satellites, leading to reduced costs for science missions.
- ericbarrett 5y ago
  That's negating the cost of the telescope itself, though. JWST may be more expensive than something you could launch with e.g. Starship, due to the need to fit into an Ariane 5 payload, but it's still an insanely high-precision instrument that would surely have cost $billions even without the unfolding procedure. If you could refuel it for, say, $250 million, because Starship, why not do that instead of launching a new telescope for $5 billion?
  - sebzim4500 5y ago
    I agree with your point but I think that $5 billion is an overestimate for a telescope as capable as JWST which is much less mass/volume constrained. ELT, a ground based telescope vastly more capable than JWST, is expected to cost €1.3 billion.
    - ericbarrett 5y ago
      I don't think ground-based telescopes are really comparable to space-based. Just one of the issues with JWST is the exotic construction required for heat management, which would be an issue for any space telescope even if it was teleported into orbit. This is comparably not an issue with ground-based stuff where you have infinite power, coolant, and heat sinks; e.g. for the ELT: "ESO is aiming to implement proven technologies and commercial off-the-shelf components to build the cryogenic infrastructure for the ELT instruments. A combination of open loop Liquid Nitrogen cooling and low-vibration mechanical cryo-coolers will be installed to provide the required temperature levels and cooling capacities."[0] I grew up at Lick Observatory in the Bay Area, and really love ground-based stuff, but I'm somewhat familiar with their operations and I guarantee it's got nothing on space 'scopes. [0] https://www.eso.org/sci/libraries/SPIE2018/10706-47.pdf https://www.eso.org/sci/libraries/SPIE2018/10706-47.pdf
      - Robotbeat 5y ago
        You yourself are making a good argument for why massive reduction in launch costs (like 3 or 4 orders of magnitude compared to Ariane) changes things dramatically. Heat management becomes easier when you can afford liquid cryogens like Spitzer or a larger and cheaper (more ground-like) cryocooler. You literally could have 1000 tons of liquid nitrogen delivered to your telescope if you needed to, if it saved $1 billion. I think people still aren’t understanding the ambitions of Starship. We’re not talking about a 30% improvement in cost. But a 300000% improvement in part because you could even afford human technicians…
        ericbarrett 5y ago
- jofer 5y ago
  Refuelling satellites is currently a hot topic in the aerospace world. No matter how cheap launch gets (and there are some very real limits to how cheap it can get for orbits like what the JWT is in), the hardware itself is quite expensive and it's often worth maintaining older scientific missions for continuity. Propellant is often a key limitation to life of a satellite, especially for earth-observations sats in low earth orbit (the opposite of the JWT), and it's well worth refuelling a satellite in principle. The JWT is a _lot_ of expensive hardware. It's not crazy at all to think about refuelling, especially if it's expending significant propellant to say in a stable orbit +/- maneuver for imaging operations. All that having been said, refuelling is still a long way from reality, and despite a lot of companies marketing refuelling ports and similar things, it will be a long while time until it's a realistic solution. Over the lifetime of the JWT, it probably will become feasible, though.
  - richardwhiuk 5y ago
    Refuelling seems to be more like to be done by bolting another engine + propellant, than actually refuelling the in-service engine, based on current concepts.
    - jofer 5y ago
      Some commercial companies (e.g. Orbit Fab) are selling refuelling ports for satellites, FWIW. NASA put a lot of research into it as well, IIRC. For the JWT it's probably quite different, but for commercial earth observation sats, there are lots of folks considering including some of the refuelling port designs in current hardware even though the actually "refuel in space" service isn't available yet.
- gameswithgo 5y ago
  I too am a big fan of SpaceX but I think it is fair to say things like "If SpaceX Starship" rather than assume it is going to work and work affordably.
  - jjoonathan 5y ago
    Agreed. Also a fan of SpaceX, but I think NASA's approach is 100% reasonable: quietly prepare plans to take advantage of starship (see: LUVOIR) but wait until Starship is proven to do the high level push to switch.
- dredmorbius 5y ago
  I suspect you're being excessively dinged for the absolute statement that refueling will be completely unneeded. It's fair to say that over two decades, additional capabilities will exist. Given the advances in launch systems, both in situ assembly (large structures w/o complex packaging and deployments), and planned servicing and replaceability could mean that both arguments are true: - We'll have bigger, more capable, and/or simply more observatories. - Those themselves will be capable of being serviced and upgraded over their own lifetimes. Keep in mind that one element of science that's advanced by such projects is engineering systems for space environments themselves. Vacuum, radiation, micrometeorites, station-keeping, gravitational flux and variance, materials handling (cold-welding, lubrcation, moving parts, etc.), thermal management, and design-for-servicing itself, all factor in to considerations. It seems highly probable to me that any such servicing itself will all but certainly be robotic. At L2, speed-of-light issues are a factor as there is a one-way signal time of five seconds, long enough that direct control of physical manipulators is no longer feasible, or very slow. (Imagine that you reach for a wrench, and ten seconds later, see that your hand has actually extended and contacted it.) And putting humans in such a location, only reachable over many days or weeks, well out of Earth's magnetosphere radiation projection, would be fantastically expensive.
  - shagie 5y ago
    > - We'll have bigger, more capable, and/or simply more observatories. The LUVOIR is the next generation - https://asd.gsfc.nasa.gov/luvoir/ https://asd.gsfc.nasa.gov/luvoir/ and https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr... The design for it is really impressive. > LUVOIR Architecture A (LUVOIR-A) features a 15-m diameter primary telescope aperture and four serviceable instruments JWST has a 6.5 meter mirror.
    - lamontcg 5y ago
      In 20 years we might be able to spamcraft a bunch of ~3m space telescopes and be able to measure their positions with sufficient precision to enable long baseline interferometry in the IR and optical spectrum. We might never build this large of a single instrument again.
- hourislate 5y ago
  How dare you share your opinion and positive outlook about SpaceX. I wouldn't worry about the junks, they're fake internet points that mean nothing.
- cletus 5y ago
  I suspect the only "controversy" in your comment is that you said something positive about SpaceX. I believe the GP is correct: wear and tear on existing components means that fuel won't be the only issue in 20 years. Hubble has been serviced 5 times [1] for example. Part of the complexity (and thus cost) for JWST was all the issues introduced by trying to fit a 6.5m mirror on existing rockets. All those moving parts and points of failure have design costs. What you may find in 20 years is that we'll want to launch an even larger mirror and/or use interferometry between multiple telescopes to improve effective resolution. [1]: https://www.space.com/15892-hubble-space-telescope.html#:~:text=Hubble%20has%20been%20serviced%20five,an%20internal%20optical%20correction%20system https://www.space.com/15892-hubble-space-telescope.html#:~:t....)
  - deleted 5y ago
    [deleted]
  - engineer_22 5y ago
    It's weird, Musk was the golden child on HN about 2 years ago when he was electrifying cars, now a pariah because of his wealth.
    - autokad 5y ago
      its very hard to build something. its really easy to tear something/someone down
    - cletus 5y ago
      There's two things that go into that IMHO: 1. People like to hate on things and people just because they're popular when there's literally no other reason; and 2. A large number of people will let their personal opinion drive their behaviour. Elon is a dick, no question. Because of that some people will just downvote or speak ill of SpaceX or Tesla. Worse, this dislike can be used to rationalize pretty antisocial behaviour (eg doxxing, swatting). What SpaceX has done is nothing short of astounding whether you like him or not. I'm not sure of the exact number but I believe SpaceX has raised <$20B and brought launch costs from >$50k/kg (Space Shuttle) to $1-2k/kg to LEO. It seems highly likely that Starship will drive that below $1k/kg, possibly by a lot. By comparison, a single SLS/Artemis launch is likely to cost more than that. And if you think it's just a question of throwing money at the problem, just look at the abject failure that is Blue Origin (fun fact: Blue Origin was founded 3-4 years before SpaceX).
- autokad 5y ago
  yeah, the capabilities of JWST was limited by its size which was limited by payload capacity. Also its cost was driven up by lots of things to deal with the size problems, like all of its folding stuff. We could put up something cheaper and better today if we just had the payload capacity.
- Robotbeat 5y ago
  Additionally, you might prefer to leverage the low launch cost to use a different approach than JWST uses. Basically, Big Spitzer. Instead of a huge sunshade, use a telescope tube and a huge amount of liquid helium (even the relatively small amount in Spitzer lasted many years, and this is one instance where mass directly translates into time). Instead of big unfolding mirror, use a monolithic one. This would actually be technically superior to Webb (colder mirror and instruments than you can get with the typical Webb cryocooler, less starlight impacting the instruments as your telescope tube with baffles shields it better, less diffraction off the mirror segment interfaces) and ought to be potentially much simpler and cheaper. And you could afford to build more than one, allowing you to reduce risk aversion slightly and increase telescope time.
- spookthesunset 5y ago
  I’m not sure if the launch cost was a driving factor in JWST’s price tag. Granted a lot of the engineering was constrained around how to deal with the massive forces involved in launch but I suspect those forces will still be in play with starship. Yeah you might be able to get bigger and heavier but it still needs to contend with launch forces. Now assembling it in space might change things… but I’m sure that has its own challenges. And even then you’d probably want a space elevator instead of rockets to get your people and equipment int local orbit.
  - samwillis 5y ago
    I think the idea is that if the launch cost is so much lower you can take more risk with the design as you can more easily justify launching again or take a more iterative design approach. The Arian 5 costs around $185M to launch, they therefore need to make sure it works first time. Starship is estimated to be $2-10M.
    - dlp211 5y ago
      The JWST cost nearly $10 Billion and 24 years to build on earth. This is not a launch cost problem.
      - space_ghost 5y ago
        How much of that time and money was R&D and prototyping, and how much of that was the bespoke production of this single unit?
        dr_orpheus 5y ago
        There is some previous discussion on what it would cost to manufacture a copy of JWST in this discussion https://news.ycombinator.com/item?id=29725799 https://news.ycombinator.com/item?id=29725799 Speculation is somewhere in the 70%-90% of original cost.
        5y ago
- baq 5y ago
  cost to refuel JWST: $500M cost of a new JWST without a foldable mirror and a static sunshield: $2B why not do both?
- YXNjaGVyZWdlbgo 5y ago
  Please at least let it reach orbital flight before we start dreaming.
- BitwiseFool 5y ago
  Cost is important, certainly, but the available space inside of the payload fairing is going to be a huge boon for future telescopes. From what I recall, a tremendous amount of effort went into folding up the JWST just so it would fit in the small space provided by the biggest rocket they could get in 1997.
khuey 5y ago
It also may just be technologically obsolete in 20 years.
- Sebb767 5y ago
  This is helped a lot by the fact that's it's quite hard [EDIT: = expensive] to place an upgraded telescope somewhere. Hubble is still used despite it's tech being a few decades old.
  - wolfram74 5y ago
    I'm trying to parse those sentences, are you saying there are space constraints with hubble? it's orbit isn't at a particularly special elevation or inclination, I'm pretty sure we could have several telescopes in the same exact orbit but half an hour behind with no discernible consequences. Even out at the lagrange points, you don't have to be /exactly/ there, many cubic kilometers of space have roughly the same properties that make it appealing for JWST.
    - Sebb767 5y ago
      It's really expensive to get telescopes up in space. We have a lot of astronomers that could use some time on a space telescope, but launching enough to supply all of them is not economically viable in any way. Sure, the stuff hubble is currently used for is not as groundbreaking as when it was launch, but we still have use for it. My point it is, we have so few space telescopes that even having time on an "outdated" one is still pretty valuable. EDIT: Maybe a better example, it's not much use for a first-world person to use a ten year old smartphone, since current smartphones are much more capable and they're comparatively cheap. Planes, on the other hand, are used for decades, since simply buying a new one is very expensive. This is despite it's tech being far superior.
  - defaultname 5y ago
    Putting a device into space is relatively cheap for a project like this, and is only dropping with each year. Say $100M - $200M, on a $10B project, puts the launch at just 1-2% of the price tag. I believe the Hubble total project cost is pushing past $16B in adjusted dollars. It's the massive capital expenditure on the telescope and its infrastructure that is the significant limiting factor on the pace of putting newer and better telescopes in place.
_joel 5y ago
Given the forthcoming availability of larger diameter rocket fairings, I think we'll see a number launched that will make JWST obsolete at the end of 20 years, but who knows!
- immmmmm 5y ago
  the large rocket you're talking about has been said to possibly make that particular company bankrupt if they don't manage to ramp up their engine production soon. and the market for heavy launch vehicle is tiny. only 3 FH were flown as far as i know. also the irony here is that the only the only client this company has now is itself to launch his telecom satellite swarm, which in turn will have a negative effect on ground observations, both in VIS and RF bands. astronomers heavily rely on ground based observations, because on the contrary to space telescope the can modify their instruments easily. you can do a lot with other technologies, for instance diffractive lenses, chronographs as a separate spaceship, etc, etc... the best for a telescope is not always to have the biggest single piece mirror. i know i know, i'll get heavily downvoted for the above, i just don't like that the said company test their stuff in a middle of a natural reservation.
  - chinathrow 5y ago
    > has been said to possibly make that particular company bankrupt if they don't manage to ramp up their engine production soon. and the market for heavy launch vehicle is tiny. I read Musk's statements regarding this towards his workforce as a pure power play to put pressure on them working even harder on ongoing issues like you mentioned.
    - micromacrofoot 5y ago
      So is there any indication his statements aren't true?
      - chinathrow 5y ago
        I don't have any insights into this but that wasn't my point. I simply pointed out my opinion, that the message was so intense, that it was looking to me as a pressure play. That being said - if you can produce n amount of engines per time frame, I am positive that they manage to achieve n*x amount of engines per the same time frame as well.
dralley 5y ago
That's probably true. There's still cause for optimism, NASA hardware has a reputation for outlasting its designed lifetime by quite a bit.
mkoubaa 5y ago
I wonder how well the child comments will age in 20 years
deleted 5y ago
[deleted]
baq 5y ago
reaction wheels are a new kind which does not suffer from failures like the Kepler - this is a very recent development. electronics on the voyager still work, 45 years after launch. it is possible that things will break. it is also possible that they won't. we'll see in 20 years, but having an option on the table in case they do work is simply prudent engineering.
dr_orpheus 5y ago
I generally agree with your assessment that there are other moving mechanical assemblies that are likely to fail at some point as well so the practicality of re-fueling may not be optimal. But I also just wanted to point out as people discuss re-fueling that some of the concepts for this are not just open up the fuel tank and add more fuel but it might be operationally simpler to make a satellite that attaches like a jetpack [0] [0] https://en.wikipedia.org/wiki/Mission_Extension_Vehicle https://en.wikipedia.org/wiki/Mission_Extension_Vehicle
zeristor 5y ago
the reaction wheels have failed on a number previous missions, it appears to be down to solar storms inducing current in the spacecraft and arcing across the bearings causing pitting, and so increased friction. I don't think they can know for sure, however the bearings have been designed with this in mind using ceramics. Also I just realised with the JSWT going around the L2 point it won't be cutting through the Earth's magnetic field, mind you it will be exposed to the direct solar wind.

samwillis 5y ago

With SpaceX Starship the space industry is going to be very different in 20 years time. Launching new telescopes, even larger ones, will be much easer. Attempts to refuel will be completely unneeded. Edit: This seems to be a controversial opinion (based on down votes). To clarify, my expectation is that if launch costs have come down as much as people suggest, launching a new and improved (potentially significantly larger) space telescope would be a better use of funds than a complicated and risky refuelling mission. There will be many lessons learnt from JWST that by then there will be an appetite for something new. My hope also is that if the cost to launch has come down so would the development costs of any new satellites, leading to reduced costs for science missions.

ericbarrett 5y ago
That's negating the cost of the telescope itself, though. JWST may be more expensive than something you could launch with e.g. Starship, due to the need to fit into an Ariane 5 payload, but it's still an insanely high-precision instrument that would surely have cost $billions even without the unfolding procedure. If you could refuel it for, say, $250 million, because Starship, why not do that instead of launching a new telescope for $5 billion?
- sebzim4500 5y ago
  I agree with your point but I think that $5 billion is an overestimate for a telescope as capable as JWST which is much less mass/volume constrained. ELT, a ground based telescope vastly more capable than JWST, is expected to cost €1.3 billion.
  - ericbarrett 5y ago
    I don't think ground-based telescopes are really comparable to space-based. Just one of the issues with JWST is the exotic construction required for heat management, which would be an issue for any space telescope even if it was teleported into orbit. This is comparably not an issue with ground-based stuff where you have infinite power, coolant, and heat sinks; e.g. for the ELT: "ESO is aiming to implement proven technologies and commercial off-the-shelf components to build the cryogenic infrastructure for the ELT instruments. A combination of open loop Liquid Nitrogen cooling and low-vibration mechanical cryo-coolers will be installed to provide the required temperature levels and cooling capacities."[0] I grew up at Lick Observatory in the Bay Area, and really love ground-based stuff, but I'm somewhat familiar with their operations and I guarantee it's got nothing on space 'scopes. [0] https://www.eso.org/sci/libraries/SPIE2018/10706-47.pdf https://www.eso.org/sci/libraries/SPIE2018/10706-47.pdf
    - Robotbeat 5y ago
      You yourself are making a good argument for why massive reduction in launch costs (like 3 or 4 orders of magnitude compared to Ariane) changes things dramatically. Heat management becomes easier when you can afford liquid cryogens like Spitzer or a larger and cheaper (more ground-like) cryocooler. You literally could have 1000 tons of liquid nitrogen delivered to your telescope if you needed to, if it saved $1 billion. I think people still aren’t understanding the ambitions of Starship. We’re not talking about a 30% improvement in cost. But a 300000% improvement in part because you could even afford human technicians…
      - ericbarrett 5y ago
jofer 5y ago
Refuelling satellites is currently a hot topic in the aerospace world. No matter how cheap launch gets (and there are some very real limits to how cheap it can get for orbits like what the JWT is in), the hardware itself is quite expensive and it's often worth maintaining older scientific missions for continuity. Propellant is often a key limitation to life of a satellite, especially for earth-observations sats in low earth orbit (the opposite of the JWT), and it's well worth refuelling a satellite in principle. The JWT is a _lot_ of expensive hardware. It's not crazy at all to think about refuelling, especially if it's expending significant propellant to say in a stable orbit +/- maneuver for imaging operations. All that having been said, refuelling is still a long way from reality, and despite a lot of companies marketing refuelling ports and similar things, it will be a long while time until it's a realistic solution. Over the lifetime of the JWT, it probably will become feasible, though.
- richardwhiuk 5y ago
  Refuelling seems to be more like to be done by bolting another engine + propellant, than actually refuelling the in-service engine, based on current concepts.
  - jofer 5y ago
    Some commercial companies (e.g. Orbit Fab) are selling refuelling ports for satellites, FWIW. NASA put a lot of research into it as well, IIRC. For the JWT it's probably quite different, but for commercial earth observation sats, there are lots of folks considering including some of the refuelling port designs in current hardware even though the actually "refuel in space" service isn't available yet.
gameswithgo 5y ago
I too am a big fan of SpaceX but I think it is fair to say things like "If SpaceX Starship" rather than assume it is going to work and work affordably.
- jjoonathan 5y ago
  Agreed. Also a fan of SpaceX, but I think NASA's approach is 100% reasonable: quietly prepare plans to take advantage of starship (see: LUVOIR) but wait until Starship is proven to do the high level push to switch.
dredmorbius 5y ago
I suspect you're being excessively dinged for the absolute statement that refueling will be completely unneeded. It's fair to say that over two decades, additional capabilities will exist. Given the advances in launch systems, both in situ assembly (large structures w/o complex packaging and deployments), and planned servicing and replaceability could mean that both arguments are true: - We'll have bigger, more capable, and/or simply more observatories. - Those themselves will be capable of being serviced and upgraded over their own lifetimes. Keep in mind that one element of science that's advanced by such projects is engineering systems for space environments themselves. Vacuum, radiation, micrometeorites, station-keeping, gravitational flux and variance, materials handling (cold-welding, lubrcation, moving parts, etc.), thermal management, and design-for-servicing itself, all factor in to considerations. It seems highly probable to me that any such servicing itself will all but certainly be robotic. At L2, speed-of-light issues are a factor as there is a one-way signal time of five seconds, long enough that direct control of physical manipulators is no longer feasible, or very slow. (Imagine that you reach for a wrench, and ten seconds later, see that your hand has actually extended and contacted it.) And putting humans in such a location, only reachable over many days or weeks, well out of Earth's magnetosphere radiation projection, would be fantastically expensive.
- shagie 5y ago
  > - We'll have bigger, more capable, and/or simply more observatories. The LUVOIR is the next generation - https://asd.gsfc.nasa.gov/luvoir/ https://asd.gsfc.nasa.gov/luvoir/ and https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infrared_Surveyor https://en.wikipedia.org/wiki/Large_Ultraviolet_Optical_Infr... The design for it is really impressive. > LUVOIR Architecture A (LUVOIR-A) features a 15-m diameter primary telescope aperture and four serviceable instruments JWST has a 6.5 meter mirror.
  - lamontcg 5y ago
    In 20 years we might be able to spamcraft a bunch of ~3m space telescopes and be able to measure their positions with sufficient precision to enable long baseline interferometry in the IR and optical spectrum. We might never build this large of a single instrument again.
hourislate 5y ago
How dare you share your opinion and positive outlook about SpaceX. I wouldn't worry about the junks, they're fake internet points that mean nothing.
cletus 5y ago
I suspect the only "controversy" in your comment is that you said something positive about SpaceX. I believe the GP is correct: wear and tear on existing components means that fuel won't be the only issue in 20 years. Hubble has been serviced 5 times [1] for example. Part of the complexity (and thus cost) for JWST was all the issues introduced by trying to fit a 6.5m mirror on existing rockets. All those moving parts and points of failure have design costs. What you may find in 20 years is that we'll want to launch an even larger mirror and/or use interferometry between multiple telescopes to improve effective resolution. [1]: https://www.space.com/15892-hubble-space-telescope.html#:~:text=Hubble%20has%20been%20serviced%20five,an%20internal%20optical%20correction%20system https://www.space.com/15892-hubble-space-telescope.html#:~:t....)
- deleted 5y ago
  [deleted]
- engineer_22 5y ago
  It's weird, Musk was the golden child on HN about 2 years ago when he was electrifying cars, now a pariah because of his wealth.
  - autokad 5y ago
    its very hard to build something. its really easy to tear something/someone down
  - cletus 5y ago
    There's two things that go into that IMHO: 1. People like to hate on things and people just because they're popular when there's literally no other reason; and 2. A large number of people will let their personal opinion drive their behaviour. Elon is a dick, no question. Because of that some people will just downvote or speak ill of SpaceX or Tesla. Worse, this dislike can be used to rationalize pretty antisocial behaviour (eg doxxing, swatting). What SpaceX has done is nothing short of astounding whether you like him or not. I'm not sure of the exact number but I believe SpaceX has raised <$20B and brought launch costs from >$50k/kg (Space Shuttle) to $1-2k/kg to LEO. It seems highly likely that Starship will drive that below $1k/kg, possibly by a lot. By comparison, a single SLS/Artemis launch is likely to cost more than that. And if you think it's just a question of throwing money at the problem, just look at the abject failure that is Blue Origin (fun fact: Blue Origin was founded 3-4 years before SpaceX).
autokad 5y ago
yeah, the capabilities of JWST was limited by its size which was limited by payload capacity. Also its cost was driven up by lots of things to deal with the size problems, like all of its folding stuff. We could put up something cheaper and better today if we just had the payload capacity.
Robotbeat 5y ago
Additionally, you might prefer to leverage the low launch cost to use a different approach than JWST uses. Basically, Big Spitzer. Instead of a huge sunshade, use a telescope tube and a huge amount of liquid helium (even the relatively small amount in Spitzer lasted many years, and this is one instance where mass directly translates into time). Instead of big unfolding mirror, use a monolithic one. This would actually be technically superior to Webb (colder mirror and instruments than you can get with the typical Webb cryocooler, less starlight impacting the instruments as your telescope tube with baffles shields it better, less diffraction off the mirror segment interfaces) and ought to be potentially much simpler and cheaper. And you could afford to build more than one, allowing you to reduce risk aversion slightly and increase telescope time.
spookthesunset 5y ago
I’m not sure if the launch cost was a driving factor in JWST’s price tag. Granted a lot of the engineering was constrained around how to deal with the massive forces involved in launch but I suspect those forces will still be in play with starship. Yeah you might be able to get bigger and heavier but it still needs to contend with launch forces. Now assembling it in space might change things… but I’m sure that has its own challenges. And even then you’d probably want a space elevator instead of rockets to get your people and equipment int local orbit.
- samwillis 5y ago
  I think the idea is that if the launch cost is so much lower you can take more risk with the design as you can more easily justify launching again or take a more iterative design approach. The Arian 5 costs around $185M to launch, they therefore need to make sure it works first time. Starship is estimated to be $2-10M.
  - dlp211 5y ago
    The JWST cost nearly $10 Billion and 24 years to build on earth. This is not a launch cost problem.
    - space_ghost 5y ago
      How much of that time and money was R&D and prototyping, and how much of that was the bespoke production of this single unit?
      - dr_orpheus 5y ago
        There is some previous discussion on what it would cost to manufacture a copy of JWST in this discussion https://news.ycombinator.com/item?id=29725799 https://news.ycombinator.com/item?id=29725799 Speculation is somewhere in the 70%-90% of original cost.
        5y ago
baq 5y ago
cost to refuel JWST: $500M cost of a new JWST without a foldable mirror and a static sunshield: $2B why not do both?
YXNjaGVyZWdlbgo 5y ago
Please at least let it reach orbital flight before we start dreaming.
BitwiseFool 5y ago
Cost is important, certainly, but the available space inside of the payload fairing is going to be a huge boon for future telescopes. From what I recall, a tremendous amount of effort went into folding up the JWST just so it would fit in the small space provided by the biggest rocket they could get in 1997.

khuey 5y ago

It also may just be technologically obsolete in 20 years.

Sebb767 5y ago
This is helped a lot by the fact that's it's quite hard [EDIT: = expensive] to place an upgraded telescope somewhere. Hubble is still used despite it's tech being a few decades old.
- wolfram74 5y ago
  I'm trying to parse those sentences, are you saying there are space constraints with hubble? it's orbit isn't at a particularly special elevation or inclination, I'm pretty sure we could have several telescopes in the same exact orbit but half an hour behind with no discernible consequences. Even out at the lagrange points, you don't have to be /exactly/ there, many cubic kilometers of space have roughly the same properties that make it appealing for JWST.
  - Sebb767 5y ago
    It's really expensive to get telescopes up in space. We have a lot of astronomers that could use some time on a space telescope, but launching enough to supply all of them is not economically viable in any way. Sure, the stuff hubble is currently used for is not as groundbreaking as when it was launch, but we still have use for it. My point it is, we have so few space telescopes that even having time on an "outdated" one is still pretty valuable. EDIT: Maybe a better example, it's not much use for a first-world person to use a ten year old smartphone, since current smartphones are much more capable and they're comparatively cheap. Planes, on the other hand, are used for decades, since simply buying a new one is very expensive. This is despite it's tech being far superior.
- defaultname 5y ago
  Putting a device into space is relatively cheap for a project like this, and is only dropping with each year. Say $100M - $200M, on a $10B project, puts the launch at just 1-2% of the price tag. I believe the Hubble total project cost is pushing past $16B in adjusted dollars. It's the massive capital expenditure on the telescope and its infrastructure that is the significant limiting factor on the pace of putting newer and better telescopes in place.

_joel 5y ago

Given the forthcoming availability of larger diameter rocket fairings, I think we'll see a number launched that will make JWST obsolete at the end of 20 years, but who knows!

immmmmm 5y ago
the large rocket you're talking about has been said to possibly make that particular company bankrupt if they don't manage to ramp up their engine production soon. and the market for heavy launch vehicle is tiny. only 3 FH were flown as far as i know. also the irony here is that the only the only client this company has now is itself to launch his telecom satellite swarm, which in turn will have a negative effect on ground observations, both in VIS and RF bands. astronomers heavily rely on ground based observations, because on the contrary to space telescope the can modify their instruments easily. you can do a lot with other technologies, for instance diffractive lenses, chronographs as a separate spaceship, etc, etc... the best for a telescope is not always to have the biggest single piece mirror. i know i know, i'll get heavily downvoted for the above, i just don't like that the said company test their stuff in a middle of a natural reservation.
- chinathrow 5y ago
  > has been said to possibly make that particular company bankrupt if they don't manage to ramp up their engine production soon. and the market for heavy launch vehicle is tiny. I read Musk's statements regarding this towards his workforce as a pure power play to put pressure on them working even harder on ongoing issues like you mentioned.
  - micromacrofoot 5y ago
    So is there any indication his statements aren't true?
    - chinathrow 5y ago
      I don't have any insights into this but that wasn't my point. I simply pointed out my opinion, that the message was so intense, that it was looking to me as a pressure play. That being said - if you can produce n amount of engines per time frame, I am positive that they manage to achieve n*x amount of engines per the same time frame as well.

dralley 5y ago

That's probably true. There's still cause for optimism, NASA hardware has a reputation for outlasting its designed lifetime by quite a bit.

mkoubaa 5y ago

I wonder how well the child comments will age in 20 years

deleted 5y ago

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baq 5y ago

reaction wheels are a new kind which does not suffer from failures like the Kepler - this is a very recent development. electronics on the voyager still work, 45 years after launch. it is possible that things will break. it is also possible that they won't. we'll see in 20 years, but having an option on the table in case they do work is simply prudent engineering.

dr_orpheus 5y ago

I generally agree with your assessment that there are other moving mechanical assemblies that are likely to fail at some point as well so the practicality of re-fueling may not be optimal. But I also just wanted to point out as people discuss re-fueling that some of the concepts for this are not just open up the fuel tank and add more fuel but it might be operationally simpler to make a satellite that attaches like a jetpack [0] [0] https://en.wikipedia.org/wiki/Mission_Extension_Vehicle https://en.wikipedia.org/wiki/Mission_Extension_Vehicle

zeristor 5y ago

the reaction wheels have failed on a number previous missions, it appears to be down to solar storms inducing current in the spacecraft and arcing across the bearings causing pitting, and so increased friction. I don't think they can know for sure, however the bearings have been designed with this in mind using ceramics. Also I just realised with the JSWT going around the L2 point it won't be cutting through the Earth's magnetic field, mind you it will be exposed to the direct solar wind.