9 ms·

It's my personal belief that these massive R&D space telescope programs are nearing their end. Computational approaches among multiple sensors, combined with go

by bane 5y ago

It's my personal belief that these massive R&D space telescope programs are nearing their end. Computational approaches among multiple sensors, combined with good 'ol factory mass manufacturing powered by low-cost reusable launch technology allows for the money spent on one-shot programs like this to be spent and allocated in radical different ways. Instead of building one huge short life-span spacecraft, why not launch hundreds or thousands of lower cost, less capable birds incrementally? You can start with a small "first light" capable instrument with a dozen or so spacecraft, then over time and more launches put up more and more capability and decommission failed or low capability pieces. Use some computational methods to combine the sensor collection from dozens, hundreds, or thousands of these kinds of spacecraft and you could end up with planet sized instruments pretty efficiently. By eliminating lots of the hard engineering for the massive instruments (like serviceability, difficult to make massive mirrors, etc) you can build even better instruments that are generational and relatively inexpensive. You get a more flexible funding story as well, e.g. fund at maintenance levels during difficult economic times and fund at larger amounts during boom times with matching launch schedules. Tasking the fleet could be more dynamic as well, with different researchers able to reserve different percentages of a huge fleet for their specific experiments and needs -- e.g. reserve a hundred spacecraft for a long dwell "deep field" type observation, or reserve thousands for planetary imaging in a nearby solar system. I know there are naysayers about this who think it's improbable. I urge those to think about the Starlink fleet, which went from zero birds in the air in 2015 to over 1500 spacecraft today. Now instead of radio antenna, what if they had imaging sensors and were turned to face out? SpaceX certainly didn't spend anywhere near what JWST ran as a program to reach this point and the development time has been a fraction so far.

nine_k 5y ago
As already said, the problem is in coordination of multiple telescopes in spacetime. It might be better to build one giant telescope piecemeal, by adding more and more small mirrors. A similar approach is taken by several terrestrial telescopes. It would still be very interesting to have a few space telescopes distributed across the Solar system, much wider than the Earth orbit. It could give a sort of stereoscopic picture of closest star systems, even though "simultaneous" observation would be ill-defined for them.
- imglorp 5y ago
  Actually, pulsars can be used for timing and position, and all telescopes in your fleet could have sight of the same ones. It's probably far easier to do interferometry if you don't have atmospheric distortion to deal with.
  - nine_k 5y ago
    Accordung to the theory of relativity, there's no such thing as "the same moment" between two distant bodies. When the distance is light milliseconds, we can pretend it does not exist. When it is light-seconds, like between Earth and GEO, it becomes hard to ignore. With many light hours which would separate the telescopes I was talking about, the idea of "the same moment" just becomes nonsensical, even in very approximate household terms. Such telescopes could, of course, register the same compact body, like an exoplanet, and then their pictures could be put together on one timeline, the planet's, thus synchronized. Maybe if a pulsar happens to be close (in angular terms) to the object observed, it could help synchronize the pictures. If the pulsar lies in a seriously different direction, it likely would be less helpful: most pulsars have rather short periods, and all pulses are the same.
  - Rebelgecko 5y ago
    OTOH it's much harder to do interferometry when you aren't able to sit on the ground and be stable: your refrigeration units can't be located somewhere far away to reduce vibration, and you can't stationkeep with nanometer accuracy (which may or may not matter depending on your frequency- in the past space based interferometry has usually only been practical for very long wavelengths)
Cacti 5y ago
You need exceedingly accurate timing and transmission to do computational inference with multiple telescopes. Even minuscule errors will wreck the entire effort. It is very, very hard even with only three telescopes on earth, nevermind a hundred hurtling around in orbit communicating with lasers. The people who work on these things aren’t morons, and everyone knows the scaling factor of multiple receivers. It’s just very, very hard.
- bane 5y ago
  Sure it's hard, bit I'm not really even proposing anything new. Labeyrie has proposed such a fleet, but raw economics have put it off, not technology -- I'd hardly call him a slouch in astronomical interferometry.
skhr0680 5y ago
Phone cameras show both the power and limits of computational photography. You can’t run away from physics forever.
- whoisburbansky 5y ago
  Phone cameras don’t have multiple lenses working together that you can interpolate between to create a single giant virtual lens. The technique OP is referring to is already used for the largest ground based radio telescopes.
  - bane 5y ago
    Exactly correct. And Labeyrie has a design in place for the exact type of fleet I'm talking about.
    - mhio 5y ago
      Do you have a link to the design? I'm assuming it's a radio telescope?
      - bane 5y ago
        No the design is optical. Here's a white paper on the concept. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.cosmos.esa.int/documents/1866264/3219248/LabeyrieA_LabeyrieESAwhitePaper2019.pdf/371f2caa-e30a-40fd-b040-99af76734f97%3Ft%3D1565184643980&ved=2ahUKEwjl_pCCu9PxAhWYPM0KHXsWCJMQFjAGegQIDhAC&usg=AOvVaw2Z81efFvZCMGyv1lcZPqtj https://www.google.com/url?sa=t&source=web&rct=j&url=https:/... Labeyrie has also proposed a fleet in L2 and on the Moon.
      - PabloRobles 5y ago
        Not the OP, but I guess he is talking about the hypertelescope concept: https://hypertelescope.org/hypertelescope-en/ https://hypertelescope.org/hypertelescope-en/ For additional background, there are already optical interferometry telescopes in use, see VLTI by the European Southern Observatory (Chile, shared facility with the four VLT telescopes and some smaller telescopes).
gpt5 5y ago
Even if this computational photography vision is years away, JWST might still become obsolete quickly. SpaceX's Starship would be able carry telescopes than JWST as a single piece. This would dramatically simplify development and increase optical quality.
- manquer 5y ago
  The challenges in building a mirror that size is enormous and take years. It is not only fairing size that is limiting
  - boardwaalk 5y ago
    Wouldn't land-based telescopes already use larger mirrors than any space telescope?
    - zaarn 5y ago
      Can you launch those mirrors into space on a rocket without them turning into very fine glass dust? Cuz I bet a lot of mirrors in land-based telescopes would simply shatter or break on a launch.
      - boardwaalk 5y ago
        Haven't a clue. It's an interesting question. What kind of materials they're made out of (weight considerations?), what kind of forces they can take, what kind of support structures they require, etc.
    - marcyb5st 5y ago
      Yes they do, but you have to consider the problems that the atmosphere poses. A lot of the budget for ground telescopes goes into the adaptive optics (actuators that can deform the mirror to compensate for distortions due to non-uniform column of air above the telescope). For adaptive optics to be effective you need bigger mirrors because you can't deform a small mirror enough to counter that. Additionally, the atmosphere blocks a bunch of wavelengths that are really interesting to observe [1] so we still want to be in space for these observations. Finally, in the non distant future I believe space telescopes will ditch mirrors altogether. For instance, the proposed Aragoscope [2] would use diffraction optics instead of so called geometric optics (lenses, mirrors) to focus light. Since the material that can provide the diffraction can be anything it would be much cheaper to launch a sheet of <insert light and bendy material here> that can unfold once in space instead of incredibly precise and fragile mirrors. Also, according to Nasa, this approach can achieve ~1000 time the resolution of HST at a fraction of the price and we are only limited by the size of the disk creating the diffraction. [1] https://www.researchgate.net/figure/The-atmospheric-transmission-windows-from-radio-to-X-ray-wavelengths-Figure-created-by_fig1_327860369 https://www.researchgate.net/figure/The-atmospheric-transmis... . [2] https://www.nasa.gov/content/the-aragoscope-ultra-high-resolution-optics-at-low-cost/ https://www.nasa.gov/content/the-aragoscope-ultra-high-resol... .
techdragon 5y ago
I'm building this! Minus the "computational methods" magic... Because as someone has already commented, there are significant issues with just merging the telescope data together with computational magic. With the advent of SpaceX's Starship providing a 100% (and the 100% is crucial to the economics of this project) reusability there is significant potential to reduce many of the costs that normally increase the price of a satellite. From not throwing away a $10,000 PPOD (cubesat deployer) to the myriad cost savings available when you know the next flight is cheap and you don't need to buy a $500 part, where a $50 or even $5 part would do the job, due to the different risk profile in many smaller satellites, compared to a few larger ones. > Instead of building one huge short life-span spacecraft, why not launch hundreds or thousands of lower cost, less capable birds incrementally? You can start with a small "first light" capable instrument with a dozen or so spacecraft, then over time and more launches put up more and more capability and decommission failed or low capability pieces. Thats the basic plan in a nutshell. Start small, build up, from the ~10cm primary mirror "phase one" prototypes, to eventually using ~50cm primary mirrors. Steady progress using a standardised telescope "chassis" for each generation, with each having a specific camera/instrument rather than the common (for space telescopes) practice of having complicated multi-instrument optical pathways. Think Planet Labs, but facing out at the universe, not down towards the ground, and a non-profit/charity not a commercial company. I'll spare the whole spiel that I've regurgitated into grant proposals (space costs money and it would be nice if I didn't have to pay the entire $250,000 or more out of my own pay-check over the course of a decade) if you want to know more (or just talk about it, or offer to help, or whatever else at all) you can contact me directly (email in my HN profile) or wait till I publish the eventual website later this year, I'll be sure to post a Show HN once I have pretty pictures of hardware.
zabzonk 5y ago
> Instead of building one huge short life-span spacecraft Short life-span? How long has the Hubble been up there?
- minitoar 5y ago
  It’s the telescope of Theseus, though.
  - xref 5y ago
    Because some component bays designed to be swapped out were swapped out? Far as I know they haven’t replaced the 2.4m main mirror or the housing, you know, the “ship”
    - minitoar 5y ago
      Yes, that is the joke I was making. Thank you for explaining it.
      - vimacs2 5y ago
        I think their point was your joke doesn't make much sense when only a small subsection of the entire telescope was ever replaced.
        minitoar 5y ago
        In my opinion that's part of what makes it funny, and is also a core issue in the Ship of Theseus problem -- who's to say how much it can be changed and is still "the same thing"? Maybe the thing that was replaced was very small but was very important to the identity.
        deleted 5y ago
        [deleted]
        xref 5y ago
deleted 5y ago
[deleted]
mustardgreen 5y ago
The Starlink fleet has been a huge problem for the field of astronomy entirely do to this "move fast and break things" ethos.
mhio 5y ago
I doubt the large space telescope programs will end, there will just be other options to how they're done. Scientists will still push the state of the art (if they get the funding) which will still be expensive and might still involve big mirrors here and there for optical imaging. Building a large fleet radio telescope in space actually sounds like a good proposal for massive R&D space telescope program. Unfortunately optical interferometry as suggested isn't a thing yet. Even the physical optical interferometry we do on the ground has only become possible relatively recently. I'm not in the field so I'm not sure what's around the corner but seems to rule out Hubble/JWST/WFIRST/LUVOIRE replacements any time soon. Maybe TESS like scanning imaging would be a good fit for a fleet? The big change I hope will be easier, cheaper, regular access to space which hopefully means there won't be such unicorn projects that spend 4 years in systems testing because they _can't_ fail. > Tasking the fleet could be more dynamic as well, with different researchers able to reserve different percentages of a huge fleet for their specific experiments and needs Specific observations require specific instruments though, there's no one size fits all fit out for a fleet satellite. JWST has a very large mirror looking a near and mid infra red a long way from earth with large IR shielding. You can't do this and Kepler/Tess type imagery in a single fleet unless the sats are specifically equipped for it on the ground before launch and sent to vastly different places which kind of nullifies a really dynamic fleet. Not saying that having a standardised, cheap satellite bus that can be quickly thrown up in space won't change things, it's just not the answer to everything.
arp242 5y ago
Deploying multiple smaller telescopes was one of the designs that was considered in the 90s for what eventually became the JWT. I'm not an expert on any of this, and I don't know specifically why it was rejected, but it's not like people aren't thinking about all sorts of possibilities. Usually there's a reason they're not being done though.
deleted 5y ago
[deleted]
dreamcompiler 5y ago
> Use some computational methods to combine the sensor collection from dozens, hundreds, or thousands of these kinds of spacecraft and you could end up with planet sized instruments pretty efficiently. This kind of thing cannot currently be done at optical wavelengths no matter how much computational power you throw at it; the frequencies are simply too high to do phase capture and syncing digitally. It's done on a limited basis at the very large telescope (VLT) in Chile but the phase combiners there are optical and analog.
shawkinaw 5y ago
From watching the documentary linked in another comment, a big part of the JWST’s potential is its deep-infrared sensitivity, which in turn requires very cold temperatures and exquisite shielding, and why it will be literally 1 million miles from Earth. I don’t think you can fake that with computation.

by bane 5y ago

nine_k 5y ago

As already said, the problem is in coordination of multiple telescopes in spacetime. It might be better to build one giant telescope piecemeal, by adding more and more small mirrors. A similar approach is taken by several terrestrial telescopes. It would still be very interesting to have a few space telescopes distributed across the Solar system, much wider than the Earth orbit. It could give a sort of stereoscopic picture of closest star systems, even though "simultaneous" observation would be ill-defined for them.

imglorp 5y ago
Actually, pulsars can be used for timing and position, and all telescopes in your fleet could have sight of the same ones. It's probably far easier to do interferometry if you don't have atmospheric distortion to deal with.
- nine_k 5y ago
  Accordung to the theory of relativity, there's no such thing as "the same moment" between two distant bodies. When the distance is light milliseconds, we can pretend it does not exist. When it is light-seconds, like between Earth and GEO, it becomes hard to ignore. With many light hours which would separate the telescopes I was talking about, the idea of "the same moment" just becomes nonsensical, even in very approximate household terms. Such telescopes could, of course, register the same compact body, like an exoplanet, and then their pictures could be put together on one timeline, the planet's, thus synchronized. Maybe if a pulsar happens to be close (in angular terms) to the object observed, it could help synchronize the pictures. If the pulsar lies in a seriously different direction, it likely would be less helpful: most pulsars have rather short periods, and all pulses are the same.
- Rebelgecko 5y ago
  OTOH it's much harder to do interferometry when you aren't able to sit on the ground and be stable: your refrigeration units can't be located somewhere far away to reduce vibration, and you can't stationkeep with nanometer accuracy (which may or may not matter depending on your frequency- in the past space based interferometry has usually only been practical for very long wavelengths)

Cacti 5y ago

You need exceedingly accurate timing and transmission to do computational inference with multiple telescopes. Even minuscule errors will wreck the entire effort. It is very, very hard even with only three telescopes on earth, nevermind a hundred hurtling around in orbit communicating with lasers. The people who work on these things aren’t morons, and everyone knows the scaling factor of multiple receivers. It’s just very, very hard.

bane 5y ago
Sure it's hard, bit I'm not really even proposing anything new. Labeyrie has proposed such a fleet, but raw economics have put it off, not technology -- I'd hardly call him a slouch in astronomical interferometry.

skhr0680 5y ago

Phone cameras show both the power and limits of computational photography. You can’t run away from physics forever.

whoisburbansky 5y ago
Phone cameras don’t have multiple lenses working together that you can interpolate between to create a single giant virtual lens. The technique OP is referring to is already used for the largest ground based radio telescopes.
- bane 5y ago
  Exactly correct. And Labeyrie has a design in place for the exact type of fleet I'm talking about.
  - mhio 5y ago
    Do you have a link to the design? I'm assuming it's a radio telescope?
    - bane 5y ago
      No the design is optical. Here's a white paper on the concept. https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.cosmos.esa.int/documents/1866264/3219248/LabeyrieA_LabeyrieESAwhitePaper2019.pdf/371f2caa-e30a-40fd-b040-99af76734f97%3Ft%3D1565184643980&ved=2ahUKEwjl_pCCu9PxAhWYPM0KHXsWCJMQFjAGegQIDhAC&usg=AOvVaw2Z81efFvZCMGyv1lcZPqtj https://www.google.com/url?sa=t&source=web&rct=j&url=https:/... Labeyrie has also proposed a fleet in L2 and on the Moon.
    - PabloRobles 5y ago
      Not the OP, but I guess he is talking about the hypertelescope concept: https://hypertelescope.org/hypertelescope-en/ https://hypertelescope.org/hypertelescope-en/ For additional background, there are already optical interferometry telescopes in use, see VLTI by the European Southern Observatory (Chile, shared facility with the four VLT telescopes and some smaller telescopes).

gpt5 5y ago

Even if this computational photography vision is years away, JWST might still become obsolete quickly. SpaceX's Starship would be able carry telescopes than JWST as a single piece. This would dramatically simplify development and increase optical quality.

manquer 5y ago
The challenges in building a mirror that size is enormous and take years. It is not only fairing size that is limiting
- boardwaalk 5y ago
  Wouldn't land-based telescopes already use larger mirrors than any space telescope?
  - zaarn 5y ago
    Can you launch those mirrors into space on a rocket without them turning into very fine glass dust? Cuz I bet a lot of mirrors in land-based telescopes would simply shatter or break on a launch.
    - boardwaalk 5y ago
      Haven't a clue. It's an interesting question. What kind of materials they're made out of (weight considerations?), what kind of forces they can take, what kind of support structures they require, etc.
  - marcyb5st 5y ago
    Yes they do, but you have to consider the problems that the atmosphere poses. A lot of the budget for ground telescopes goes into the adaptive optics (actuators that can deform the mirror to compensate for distortions due to non-uniform column of air above the telescope). For adaptive optics to be effective you need bigger mirrors because you can't deform a small mirror enough to counter that. Additionally, the atmosphere blocks a bunch of wavelengths that are really interesting to observe [1] so we still want to be in space for these observations. Finally, in the non distant future I believe space telescopes will ditch mirrors altogether. For instance, the proposed Aragoscope [2] would use diffraction optics instead of so called geometric optics (lenses, mirrors) to focus light. Since the material that can provide the diffraction can be anything it would be much cheaper to launch a sheet of <insert light and bendy material here> that can unfold once in space instead of incredibly precise and fragile mirrors. Also, according to Nasa, this approach can achieve ~1000 time the resolution of HST at a fraction of the price and we are only limited by the size of the disk creating the diffraction. [1] https://www.researchgate.net/figure/The-atmospheric-transmission-windows-from-radio-to-X-ray-wavelengths-Figure-created-by_fig1_327860369 https://www.researchgate.net/figure/The-atmospheric-transmis... . [2] https://www.nasa.gov/content/the-aragoscope-ultra-high-resolution-optics-at-low-cost/ https://www.nasa.gov/content/the-aragoscope-ultra-high-resol... .

techdragon 5y ago

I'm building this! Minus the "computational methods" magic... Because as someone has already commented, there are significant issues with just merging the telescope data together with computational magic. With the advent of SpaceX's Starship providing a 100% (and the 100% is crucial to the economics of this project) reusability there is significant potential to reduce many of the costs that normally increase the price of a satellite. From not throwing away a $10,000 PPOD (cubesat deployer) to the myriad cost savings available when you know the next flight is cheap and you don't need to buy a $500 part, where a $50 or even $5 part would do the job, due to the different risk profile in many smaller satellites, compared to a few larger ones. > Instead of building one huge short life-span spacecraft, why not launch hundreds or thousands of lower cost, less capable birds incrementally? You can start with a small "first light" capable instrument with a dozen or so spacecraft, then over time and more launches put up more and more capability and decommission failed or low capability pieces. Thats the basic plan in a nutshell. Start small, build up, from the ~10cm primary mirror "phase one" prototypes, to eventually using ~50cm primary mirrors. Steady progress using a standardised telescope "chassis" for each generation, with each having a specific camera/instrument rather than the common (for space telescopes) practice of having complicated multi-instrument optical pathways. Think Planet Labs, but facing out at the universe, not down towards the ground, and a non-profit/charity not a commercial company. I'll spare the whole spiel that I've regurgitated into grant proposals (space costs money and it would be nice if I didn't have to pay the entire $250,000 or more out of my own pay-check over the course of a decade) if you want to know more (or just talk about it, or offer to help, or whatever else at all) you can contact me directly (email in my HN profile) or wait till I publish the eventual website later this year, I'll be sure to post a Show HN once I have pretty pictures of hardware.

zabzonk 5y ago

> Instead of building one huge short life-span spacecraft Short life-span? How long has the Hubble been up there?

minitoar 5y ago
It’s the telescope of Theseus, though.
- xref 5y ago
  Because some component bays designed to be swapped out were swapped out? Far as I know they haven’t replaced the 2.4m main mirror or the housing, you know, the “ship”
  - minitoar 5y ago
    Yes, that is the joke I was making. Thank you for explaining it.
    - vimacs2 5y ago
      I think their point was your joke doesn't make much sense when only a small subsection of the entire telescope was ever replaced.
      - minitoar 5y ago
        In my opinion that's part of what makes it funny, and is also a core issue in the Ship of Theseus problem -- who's to say how much it can be changed and is still "the same thing"? Maybe the thing that was replaced was very small but was very important to the identity.
        deleted 5y ago
        [deleted]
        xref 5y ago

deleted 5y ago

[deleted]

mustardgreen 5y ago

The Starlink fleet has been a huge problem for the field of astronomy entirely do to this "move fast and break things" ethos.

mhio 5y ago

I doubt the large space telescope programs will end, there will just be other options to how they're done. Scientists will still push the state of the art (if they get the funding) which will still be expensive and might still involve big mirrors here and there for optical imaging. Building a large fleet radio telescope in space actually sounds like a good proposal for massive R&D space telescope program. Unfortunately optical interferometry as suggested isn't a thing yet. Even the physical optical interferometry we do on the ground has only become possible relatively recently. I'm not in the field so I'm not sure what's around the corner but seems to rule out Hubble/JWST/WFIRST/LUVOIRE replacements any time soon. Maybe TESS like scanning imaging would be a good fit for a fleet? The big change I hope will be easier, cheaper, regular access to space which hopefully means there won't be such unicorn projects that spend 4 years in systems testing because they _can't_ fail. > Tasking the fleet could be more dynamic as well, with different researchers able to reserve different percentages of a huge fleet for their specific experiments and needs Specific observations require specific instruments though, there's no one size fits all fit out for a fleet satellite. JWST has a very large mirror looking a near and mid infra red a long way from earth with large IR shielding. You can't do this and Kepler/Tess type imagery in a single fleet unless the sats are specifically equipped for it on the ground before launch and sent to vastly different places which kind of nullifies a really dynamic fleet. Not saying that having a standardised, cheap satellite bus that can be quickly thrown up in space won't change things, it's just not the answer to everything.

arp242 5y ago

Deploying multiple smaller telescopes was one of the designs that was considered in the 90s for what eventually became the JWT. I'm not an expert on any of this, and I don't know specifically why it was rejected, but it's not like people aren't thinking about all sorts of possibilities. Usually there's a reason they're not being done though.

deleted 5y ago

[deleted]

dreamcompiler 5y ago

> Use some computational methods to combine the sensor collection from dozens, hundreds, or thousands of these kinds of spacecraft and you could end up with planet sized instruments pretty efficiently. This kind of thing cannot currently be done at optical wavelengths no matter how much computational power you throw at it; the frequencies are simply too high to do phase capture and syncing digitally. It's done on a limited basis at the very large telescope (VLT) in Chile but the phase combiners there are optical and analog.

shawkinaw 5y ago

From watching the documentary linked in another comment, a big part of the JWST’s potential is its deep-infrared sensitivity, which in turn requires very cold temperatures and exquisite shielding, and why it will be literally 1 million miles from Earth. I don’t think you can fake that with computation.