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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

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
      I'm well aware of the capabilities SpaceX is promising! This is why I said, "even if the telescope was teleported into orbit." If a new ground-based telescope is still $1 bil then something which has to operate in hard vacuum, high radiation, and with even greater temperature differences, with far less provision for repair (even with Starship), will be hard-pressed to come in at an even smaller budget. Then again, $1 bil ain't what it used to be.
      - Robotbeat 5y ago
        On the other hand, you don’t need a massive, expensive structure to keep the mirror from deforming under gravity, everything is already vacuum insulated for you, humidity isn’t a problem, you get 24/7 energy from the Sun using just solar panels (no diesel generators), you don’t have concerns for building on sacred land, you have like 3-4 times the observing time per day (which directly impacts cost per observing hour), independent of weather, access to both hemispheres, and no (or much less) need for expensive adaptive optics and laser systems to partially correct for the atmosphere.
        ericbarrett 5y ago
        All true! And mostly better for the ultimate purpose of a telescope, which is why we prefer to put them in space. However none of those advantages offset the greater cost, e.g. your "expensive structure to keep the mirror from deforming under gravity" is simply a steel scaffolding. Admittedly to higher precision than an office building, but not extraordinarily so. I think perhaps you are not respecting the challenges of space and the cost to operate reliably in it, even if launch costs were zero and mass unlimited, so I'd encourage you do do a little more research.
- kabdib 5y ago
  > vastly more capable than JWST ... not at the same wavelengths. The earth's atmosphere is largely opaque to IR, for instance.
  - dredmorbius 5y ago
    And even if not opaque, the thermal signature of the atmosphere itself would degrade signal from distant objects. There are some things you can only do beyond the atmosphere.
    - dlp211 5y ago
      Dust also greatly degrades earth based telescopes abilities.
      - dredmorbius 5y ago
        Skyglow, atmospheric distortion, atmospheric absorption of specific frequencies, wind, the Earth's inclination, orbit, and rotation (limits time-on-target for any specific target of interest), local conditions (static electricity being a major issue for the ESO in Chile, given elevation and lack of humidity, all electronics must be static-tolerant or resistant), etc., etc. Not that space isn't also hard, but each environment has both affordances and limitations.
        deleted 5y ago
        [deleted]
- soperj 5y ago
  really though, if Starship is that capable, and JWST is still usable, I think you do both. If only to test really crazy things that you haven't been able to look at before because the time was too valuable.
kemiller 5y ago
Lower launch costs could enable cheaper R&D for the satellite itself by enabling more testing of components in orbit rather than trying to nail the calculations ahead of time.

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
    I'm well aware of the capabilities SpaceX is promising! This is why I said, "even if the telescope was teleported into orbit." If a new ground-based telescope is still $1 bil then something which has to operate in hard vacuum, high radiation, and with even greater temperature differences, with far less provision for repair (even with Starship), will be hard-pressed to come in at an even smaller budget. Then again, $1 bil ain't what it used to be.
    - Robotbeat 5y ago
      On the other hand, you don’t need a massive, expensive structure to keep the mirror from deforming under gravity, everything is already vacuum insulated for you, humidity isn’t a problem, you get 24/7 energy from the Sun using just solar panels (no diesel generators), you don’t have concerns for building on sacred land, you have like 3-4 times the observing time per day (which directly impacts cost per observing hour), independent of weather, access to both hemispheres, and no (or much less) need for expensive adaptive optics and laser systems to partially correct for the atmosphere.
      - ericbarrett 5y ago
        All true! And mostly better for the ultimate purpose of a telescope, which is why we prefer to put them in space. However none of those advantages offset the greater cost, e.g. your "expensive structure to keep the mirror from deforming under gravity" is simply a steel scaffolding. Admittedly to higher precision than an office building, but not extraordinarily so. I think perhaps you are not respecting the challenges of space and the cost to operate reliably in it, even if launch costs were zero and mass unlimited, so I'd encourage you do do a little more research.
kabdib 5y ago
> vastly more capable than JWST ... not at the same wavelengths. The earth's atmosphere is largely opaque to IR, for instance.
- dredmorbius 5y ago
  And even if not opaque, the thermal signature of the atmosphere itself would degrade signal from distant objects. There are some things you can only do beyond the atmosphere.
  - dlp211 5y ago
    Dust also greatly degrades earth based telescopes abilities.
    - dredmorbius 5y ago
      Skyglow, atmospheric distortion, atmospheric absorption of specific frequencies, wind, the Earth's inclination, orbit, and rotation (limits time-on-target for any specific target of interest), local conditions (static electricity being a major issue for the ESO in Chile, given elevation and lack of humidity, all electronics must be static-tolerant or resistant), etc., etc. Not that space isn't also hard, but each environment has both affordances and limitations.
      - deleted 5y ago
        [deleted]
soperj 5y ago
really though, if Starship is that capable, and JWST is still usable, I think you do both. If only to test really crazy things that you haven't been able to look at before because the time was too valuable.

kemiller 5y ago

Lower launch costs could enable cheaper R&D for the satellite itself by enabling more testing of components in orbit rather than trying to nail the calculations ahead of time.