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NASA was developing plans for an 8 meter monolithic optical/UV space telescope concept[1]. NASA's concept videos from 17 years ago are still rattling around on

NASA was developing plans for an 8 meter monolithic optical/UV space telescope concept[1]. NASA's concept videos from 17 years ago are still rattling around on YouTube[2]. All that died when the Ares program was cancelled and the intended launch platform, Ares V, went away. Starship and SLS are supposed to have a large enough fairings. So, maybe one day... [1] https://ntrs.nasa.gov/api/citations/20090014194/downloads/20090014194.pdf https://ntrs.nasa.gov/api/citations/20090014194/downloads/20... [2] https://www.youtube.com/watch?v=2YsNvpVSzbI https://www.youtube.com/watch?v=2YsNvpVSzbI

dylan604 2y ago
After JWST, why build an monolithic mirror? If you only want visible spectrum, you wouldn't need the complexity of the heat shield of JWST. If an 8 meter primary is so much better, why not make it multiple times 8 meters similar to JWST? I understand this was something from 17 years ago, but let's just keep pushing capabilities instead of incrementing them.
- topspin 2y ago
  "why build an monolithic mirror?" "why not make it multiple times 8 meters" Cheap, simple design that doesn't take 20 years and a NASA to develop. 8m is a massive gain in angular resolution over Hubble's 2.3m and an improvement on JWST's 6.5m. From the our linked article: “Diameter is a huge lever arm,” “The larger the diameter, the better the resolution and sensitivity.” Based on the fairing specs it looks like Starship could achieve 9m. That would be nearly double the collector area of JWST. JWST is one, very expensive, exclusive design that perhaps only NASA is capable of delivering. What if someone other than the US wants a cutting edge "Great Observatories" class space telescope? A big, simple monolithic mirror design made feasible by super heavy lifters.
  - EcommerceFlow 2y ago
    Or maybe a 16m "single fold". Would the complexity of adding 1 fold be worth the benefit of a 2x size?
    - topspin 2y ago
      With its 9m fairing Starship could nearly double JWST's collector area with no folds. Big rockets solve a lot of problems.
      - johndunne 2y ago
        Or, put a JWST 2.0 with hexagonal segments each the size of the full JWST diameter, and fold that up into Starship... Yes please!
    - dylan604 2y ago
      But that's not 2x the size evenly, so I don't think that would be worthwhile. That's an advantage of the hexagonal shape that JWST used so that it could unfold to increase the size evenly.
- indoordin0saur 2y ago
  A complex unfolding mechanism makes things a lot more expensive, slower to develop and more likely to fail. If you could get an improvement over JWST delivered in 5 years at a tenth the cost that's a good option to have. Starship would theoretically allow for huge telescopes (like the 15m LUVOIR-A) but not all projects have the sort of budget or expertise for that.
  - vlovich123 2y ago
    Would building another identical JWST be meaningfully cheaper? All the R&D work would be done and we could update just the sensor package. I feel like we don’t do enough reuse in space programs and every project feels like a “from scratch” effort.
    - indoordin0saur 2y ago
      I'm not an expert, but I'd imagine a lot of it was R&D work, but also much of it was precision manufacturing that made it expensive. I do like the idea of making a bunch of identical telescopes to drive down cost and allow for more astronomers to have time on the best telescopes. We wouldn't need to make another JWST though, because Starship could just fit an unfolded telescope of that size in its fairing. The LUVOIR-A telescope is sort of a scaled-up JWST, with the folded mirrors, but from what I understand it is different enough that there are many new engineering challenges.
    - dylan604 2y ago
      Doubtful. In the time it took to develop, build, deploy JWST, most of the people that worked on it would probably no longer be around to build 2.0. So tribal knowledge would be lost.
    - mandevil 2y ago
      So a couple of things are happening here: most important is that the budget for multiple launches and physical spacecraft to do the same mission just isn't there, hasn't been there since the 1970's. Viking and Voyager each got two bites at the apple, but since then NASA has decided that their reliability is good enough to get away with one actual launch. And so the easiest form of reuse is off the table. And then since every mission is different, you end up needing different things for components. https://en.wikipedia.org/wiki/Mars_Observer https://en.wikipedia.org/wiki/Mars_Observer is what happens when you try and reuse components without fully taking into account the differences in mission. This was an early 1990's NASA Mars mission which failed because they reused an engine from Earth orbiting satellites which would always fire the engine shortly after getting into space. Probably its fuel tank failed because it was expected to lie dormant for months of travel and then fire. So the environment that HST, JWST, the Parker Solar Probe, and Juno are expected to operate in are enormously different from each other and re-using a component and having it fail because it was designed for a different environment would be really bad. Oh, and building a new JWST now would be pretty expensive, because a lot of the cost is in testing and certifying that it will do what it's supposed to do, and all of the people who built and tested the JWST have moved on and changed jobs, so all of that workforce would have to be re-created, and that's where the money goes, to pay people. If you wanted to build 8 JWST's at once, the cost wouldn't be that much more than building one JWST, but building a single new one now would be expensive.

dylan604 2y ago

After JWST, why build an monolithic mirror? If you only want visible spectrum, you wouldn't need the complexity of the heat shield of JWST. If an 8 meter primary is so much better, why not make it multiple times 8 meters similar to JWST? I understand this was something from 17 years ago, but let's just keep pushing capabilities instead of incrementing them.

topspin 2y ago
"why build an monolithic mirror?" "why not make it multiple times 8 meters" Cheap, simple design that doesn't take 20 years and a NASA to develop. 8m is a massive gain in angular resolution over Hubble's 2.3m and an improvement on JWST's 6.5m. From the our linked article: “Diameter is a huge lever arm,” “The larger the diameter, the better the resolution and sensitivity.” Based on the fairing specs it looks like Starship could achieve 9m. That would be nearly double the collector area of JWST. JWST is one, very expensive, exclusive design that perhaps only NASA is capable of delivering. What if someone other than the US wants a cutting edge "Great Observatories" class space telescope? A big, simple monolithic mirror design made feasible by super heavy lifters.
- EcommerceFlow 2y ago
  Or maybe a 16m "single fold". Would the complexity of adding 1 fold be worth the benefit of a 2x size?
  - topspin 2y ago
    With its 9m fairing Starship could nearly double JWST's collector area with no folds. Big rockets solve a lot of problems.
    - johndunne 2y ago
      Or, put a JWST 2.0 with hexagonal segments each the size of the full JWST diameter, and fold that up into Starship... Yes please!
  - dylan604 2y ago
    But that's not 2x the size evenly, so I don't think that would be worthwhile. That's an advantage of the hexagonal shape that JWST used so that it could unfold to increase the size evenly.
indoordin0saur 2y ago
A complex unfolding mechanism makes things a lot more expensive, slower to develop and more likely to fail. If you could get an improvement over JWST delivered in 5 years at a tenth the cost that's a good option to have. Starship would theoretically allow for huge telescopes (like the 15m LUVOIR-A) but not all projects have the sort of budget or expertise for that.
- vlovich123 2y ago
  Would building another identical JWST be meaningfully cheaper? All the R&D work would be done and we could update just the sensor package. I feel like we don’t do enough reuse in space programs and every project feels like a “from scratch” effort.
  - indoordin0saur 2y ago
    I'm not an expert, but I'd imagine a lot of it was R&D work, but also much of it was precision manufacturing that made it expensive. I do like the idea of making a bunch of identical telescopes to drive down cost and allow for more astronomers to have time on the best telescopes. We wouldn't need to make another JWST though, because Starship could just fit an unfolded telescope of that size in its fairing. The LUVOIR-A telescope is sort of a scaled-up JWST, with the folded mirrors, but from what I understand it is different enough that there are many new engineering challenges.
  - dylan604 2y ago
    Doubtful. In the time it took to develop, build, deploy JWST, most of the people that worked on it would probably no longer be around to build 2.0. So tribal knowledge would be lost.
  - mandevil 2y ago
    So a couple of things are happening here: most important is that the budget for multiple launches and physical spacecraft to do the same mission just isn't there, hasn't been there since the 1970's. Viking and Voyager each got two bites at the apple, but since then NASA has decided that their reliability is good enough to get away with one actual launch. And so the easiest form of reuse is off the table. And then since every mission is different, you end up needing different things for components. https://en.wikipedia.org/wiki/Mars_Observer https://en.wikipedia.org/wiki/Mars_Observer is what happens when you try and reuse components without fully taking into account the differences in mission. This was an early 1990's NASA Mars mission which failed because they reused an engine from Earth orbiting satellites which would always fire the engine shortly after getting into space. Probably its fuel tank failed because it was expected to lie dormant for months of travel and then fire. So the environment that HST, JWST, the Parker Solar Probe, and Juno are expected to operate in are enormously different from each other and re-using a component and having it fail because it was designed for a different environment would be really bad. Oh, and building a new JWST now would be pretty expensive, because a lot of the cost is in testing and certifying that it will do what it's supposed to do, and all of the people who built and tested the JWST have moved on and changed jobs, so all of that workforce would have to be re-created, and that's where the money goes, to pay people. If you wanted to build 8 JWST's at once, the cost wouldn't be that much more than building one JWST, but building a single new one now would be expensive.