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What is more useful, satellites or astronomers being able to view the stars clearly from the planets surface. Genuine question, but it seems to me that in the l

by notus 7y ago

What is more useful, satellites or astronomers being able to view the stars clearly from the planets surface. Genuine question, but it seems to me that in the long run satellites would win out.

kitd 7y ago
Well, in the really long run, a clear view of potential celestial destinations may be paramount :)
- lazyjones 7y ago
  Orbital telescopes are much better suited for this.
  - rtkwe 7y ago
    They're also much much more expensive and less flexible. With earth based satellites new experiments with new instrumentation is easy, in space currently we have no way to fix any issues.
    - thecount122195 7y ago
      We can and have fixed space telescopes before, probably the most famous example is Hubble and its poor sight. https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_mirror https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_...
      - rtkwe 7y ago
        We did but not any more 1) there's no longer anything like the shuttle available the only thing that could get close would take two launches to stage the parts and another for the crew capsule (not to mention most US capsules would have to evacuate the entire capsule to go outside iirc) and 2) most of the current space based telescopes like James Webb will be much much further out than Hubble was and most that get announced are also planned to orbit much further from Earth.
      - kuschku 7y ago
        So which space shuttle should we use to fix James Webb if anything would go wrong after the launch? Currently no country has a well-working solution for that, nor does any company (not even SpaceX themselves)
        sp332 7y ago
        JWST is for researching high-redshift object - the most distant things we can see in the universe. It's not a planet-hunter. And it will be much further away than other satellites, so they would be more easily serviced. (Not that it's easy, I just think you picked a bad example.)
        privong 7y ago
        > JWST is for researching high-redshift object - the most distant things we can see in the universe. It's not a planet-hunter. JWST is a general purpose observatory. It will make significant advances for high-redshift objects. It will not survey large numbers of star for new planets, but it will be able to observe and characterize planets that have been identified by other missions/observatories.
        mdorazio 7y ago
        Your comment assumes we still need fleshy meatbags wearing clunky suits in orbit to fix things. This was true 15 years ago, but I'm not convinced it's still true today. A couple of repair drones housed at the ISS combined with repair parts brought up along with normal resupply missions could probably be made to work if it was deemed cost effective.
        plotteddancer16 7y ago
        This is a misconception. The ISS is not in an orbit that’s suitable for repairing satellites in other orbits.
        rtkwe 7y ago
        The ISS isn't in a particularly good orbit because it's highly inclined (so Russia could easily launch to it) which is an expensive issue to fix dV wise unless all the target satellites are in a similarly inclined orbit. In terms of making them easy to swap out that's certainly possible but it will add weight compared to a monolithic satellite and so far we have very very little experience building and repairing things in space without using people.
      - monocasa 7y ago
        To be fair, that was the killer app of the space shuttle (ie. satellite interception and capture). We've lost that capability, and nothing on the medium term drawing board regains that.
        thecount122195 7y ago
        You're right we don't currently, that just means its time to boot up space race 2, I hope China's space program kicks NASA back into high gear, shift a couple of the DOD's billions around and get space race 2 electric boogaloo going.
        Robotbeat 7y ago
        Not true. SpaceX envisions using Starship (the same vehicle SpaceX would need to be able to launch 12,000 satellites) for satellite interception and capture. No Starship, no 12,000 satellites.
        rtkwe 7y ago
        You don't need Starship for limited constellations to cause issues with Earth based observations though. Also SpaceX isn't the only one that's going to be wanting to make a constellation.
        Robotbeat 7y ago
        Well in that case, we've had limited constellations that cause issues for Earth based observations for decades. (Note: this is one hint that the risk here is exaggerated... dealing with satellites has been a thing for a very, very long time. Filtering out satellite tracks is easy and common, and modern digital imaging and data storage techniques have made satellite track removal ever easier. And many satellites--particularly space stations--are orders of magnitude brighter than Starlink satellites will be.)
    - Robotbeat 7y ago
      ...with the kind of capabilities that enable megaconstellations (low cost launch, inexpensive space hardware replaced regularly every few years), neither of those things will be true. So either space astronomy becomes much easier/cheaper and we get megaconstellations, or megaconstellations won't happen.
      - rtkwe 7y ago
        Optics put a lot of design constrains on telescopes that mean they'll always be large items, when you're trying to look really far away at really dim objects you just need a lot of surface area to collect as much light as possible and the size of the object you can resolve is directly linked to the size of the aperture of the telescope you're using. Synthetic apertures using interferometry may solve that eventually but we're not there yet it looks like for really high resolution images.
        Robotbeat 7y ago
        Right, I meant cost in terms of cost per unit dry mass, not just miniaturizing existing satellites. Starlink satellites are really cheap per unit dry mass, not just per satellite. Starship will be super cheap per unit dry mass, enabling ever-larger space telescopes. NASA even tweeted out one concept out for an aperture much larger than JWST using SpaceX's Starship: https://twitter.com/nasagoddard/status/1116310431969239040?lang=en https://twitter.com/nasagoddard/status/1116310431969239040?l...
        rtkwe 7y ago
        They might get cheap to launch but they'll be quite expensive to build for the foreseeable future.
        Robotbeat 7y ago
        I don't see why they need to be. SpaceX has been able to reduce the cost of building space hardware with Starlink by an order of magnitude. When things are cheaper to launch, you can find ways to reduce the cost to build those things.
- Ajedi32 7y ago
  Yeah, but if you're thinking on those timescales you'd probably be better off using orbital telescopes, or telescopes located on other planets or moons with little to no atmosphere. Satellites and the commercialization of space will be important to enabling that level of space-borne infrastructure, so even in the really long run the utility of satellites probably still wins out.
thekingofh 7y ago
Both

by notus 7y ago

What is more useful, satellites or astronomers being able to view the stars clearly from the planets surface. Genuine question, but it seems to me that in the long run satellites would win out.

kitd 7y ago

Well, in the really long run, a clear view of potential celestial destinations may be paramount :)

lazyjones 7y ago
Orbital telescopes are much better suited for this.
- rtkwe 7y ago
  They're also much much more expensive and less flexible. With earth based satellites new experiments with new instrumentation is easy, in space currently we have no way to fix any issues.
  - thecount122195 7y ago
    We can and have fixed space telescopes before, probably the most famous example is Hubble and its poor sight. https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_mirror https://en.wikipedia.org/wiki/Hubble_Space_Telescope#Flawed_...
    - rtkwe 7y ago
      We did but not any more 1) there's no longer anything like the shuttle available the only thing that could get close would take two launches to stage the parts and another for the crew capsule (not to mention most US capsules would have to evacuate the entire capsule to go outside iirc) and 2) most of the current space based telescopes like James Webb will be much much further out than Hubble was and most that get announced are also planned to orbit much further from Earth.
    - kuschku 7y ago
      So which space shuttle should we use to fix James Webb if anything would go wrong after the launch? Currently no country has a well-working solution for that, nor does any company (not even SpaceX themselves)
      - sp332 7y ago
        JWST is for researching high-redshift object - the most distant things we can see in the universe. It's not a planet-hunter. And it will be much further away than other satellites, so they would be more easily serviced. (Not that it's easy, I just think you picked a bad example.)
        privong 7y ago
        > JWST is for researching high-redshift object - the most distant things we can see in the universe. It's not a planet-hunter. JWST is a general purpose observatory. It will make significant advances for high-redshift objects. It will not survey large numbers of star for new planets, but it will be able to observe and characterize planets that have been identified by other missions/observatories.
      - mdorazio 7y ago
        Your comment assumes we still need fleshy meatbags wearing clunky suits in orbit to fix things. This was true 15 years ago, but I'm not convinced it's still true today. A couple of repair drones housed at the ISS combined with repair parts brought up along with normal resupply missions could probably be made to work if it was deemed cost effective.
        plotteddancer16 7y ago
        This is a misconception. The ISS is not in an orbit that’s suitable for repairing satellites in other orbits.
        rtkwe 7y ago
        The ISS isn't in a particularly good orbit because it's highly inclined (so Russia could easily launch to it) which is an expensive issue to fix dV wise unless all the target satellites are in a similarly inclined orbit. In terms of making them easy to swap out that's certainly possible but it will add weight compared to a monolithic satellite and so far we have very very little experience building and repairing things in space without using people.
    - monocasa 7y ago
      To be fair, that was the killer app of the space shuttle (ie. satellite interception and capture). We've lost that capability, and nothing on the medium term drawing board regains that.
      - thecount122195 7y ago
        You're right we don't currently, that just means its time to boot up space race 2, I hope China's space program kicks NASA back into high gear, shift a couple of the DOD's billions around and get space race 2 electric boogaloo going.
      - Robotbeat 7y ago
        Not true. SpaceX envisions using Starship (the same vehicle SpaceX would need to be able to launch 12,000 satellites) for satellite interception and capture. No Starship, no 12,000 satellites.
        rtkwe 7y ago
        You don't need Starship for limited constellations to cause issues with Earth based observations though. Also SpaceX isn't the only one that's going to be wanting to make a constellation.
        Robotbeat 7y ago
        Well in that case, we've had limited constellations that cause issues for Earth based observations for decades. (Note: this is one hint that the risk here is exaggerated... dealing with satellites has been a thing for a very, very long time. Filtering out satellite tracks is easy and common, and modern digital imaging and data storage techniques have made satellite track removal ever easier. And many satellites--particularly space stations--are orders of magnitude brighter than Starlink satellites will be.)
  - Robotbeat 7y ago
    ...with the kind of capabilities that enable megaconstellations (low cost launch, inexpensive space hardware replaced regularly every few years), neither of those things will be true. So either space astronomy becomes much easier/cheaper and we get megaconstellations, or megaconstellations won't happen.
    - rtkwe 7y ago
      Optics put a lot of design constrains on telescopes that mean they'll always be large items, when you're trying to look really far away at really dim objects you just need a lot of surface area to collect as much light as possible and the size of the object you can resolve is directly linked to the size of the aperture of the telescope you're using. Synthetic apertures using interferometry may solve that eventually but we're not there yet it looks like for really high resolution images.
      - Robotbeat 7y ago
        Right, I meant cost in terms of cost per unit dry mass, not just miniaturizing existing satellites. Starlink satellites are really cheap per unit dry mass, not just per satellite. Starship will be super cheap per unit dry mass, enabling ever-larger space telescopes. NASA even tweeted out one concept out for an aperture much larger than JWST using SpaceX's Starship: https://twitter.com/nasagoddard/status/1116310431969239040?lang=en https://twitter.com/nasagoddard/status/1116310431969239040?l...
        rtkwe 7y ago
        They might get cheap to launch but they'll be quite expensive to build for the foreseeable future.
        Robotbeat 7y ago
        I don't see why they need to be. SpaceX has been able to reduce the cost of building space hardware with Starlink by an order of magnitude. When things are cheaper to launch, you can find ways to reduce the cost to build those things.
Ajedi32 7y ago
Yeah, but if you're thinking on those timescales you'd probably be better off using orbital telescopes, or telescopes located on other planets or moons with little to no atmosphere. Satellites and the commercialization of space will be important to enabling that level of space-borne infrastructure, so even in the really long run the utility of satellites probably still wins out.

thekingofh 7y ago

Both