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> The number of images partially blocked by satellites is still small, the team found, rising from nearly 3 percent of images taken between 2002 and 2005 to jus

> The number of images partially blocked by satellites is still small, the team found, rising from nearly 3 percent of images taken between 2002 and 2005 to just over 4 percent between 2018 and 2021 for one of Hubble’s cameras. > “Starlink is the densest patch of space that has ever existed,” says astronomer Samantha Lawler of the University of Regina in Canada. "The satellites are constantly navigating out of each other’s way to avoid collisions" [here a reference to a similarly alarmist study from 2009 is cited] Isn't this the point of putting telescopes in orbit? Starlink seems to at least be trying to reduce the visibility and size of its satellite fleet, but no one's working on cleaning up orbital debris - the best we have now is tracking of fairly large chunks of trash.

JohnFen 4y ago
We don't want all telescopes to have to be in orbit, though. That would raise the cost of astronomy enormously. Most astronomy is done with ground-based telescopes for pretty solid reasons.
- ricardobeat 4y ago
  A temporary problem, if cost per kg for launches comes down as predicted in the next few years.
  - JohnFen 4y ago
    I have doubts. Launch costs aren't the only thing that makes space-based telescopes very expensive.
    - techdragon 4y ago
      Having spent the time working on a space telescope design (Worked on making a cubesat amateur telescope during COVID lockdowns) it’s a significant driver of secondary costs beyond the primary “launch cost”. Space telescopes are commonly “volume constrained” not “mass constrained” like how only Ariane 5 had a fairing big enough for the James Web Space Telescope, how Hubble was as big as they could fit in the Shuttle cargo bay, and many other “big science” general purpose “an observatory in space” sort of telescopes end up expanding to fit their launch volume because the main structures are “empty tubes” or folding mirrors, or extending booms (X-ray telescope mirrors are super clever things) and so you end up with everything else around these low density telescopes structures having heaps of mass budget… but then your still looking at vibrations, ruggedness requires mass… and so the circular game of musical chairs with engineering constraints begins… and you do a lot of engineering work to keep your mission on track. With major reduction in launch costs it becomes a lot more practical to launch smaller more specifically focused telescopes like we’ve seen with Kepler, TESS and CHEOPS, there’s commercial suppliers of professional grade telescopes, which are more than enough for useful research and with ample spare launch mass they could be given the same kind of cushy ride to space that the commercial cameras you see on the ISS got… it’s a bit of work to vacuum rate something but it would be less work than a camera by far given the fewer moving parts… and so then it’s just your instruments… with lower launch costs you can get significantly better science. Astronomical grants routinely cover the development of new instruments for ground based telescopes, and the costs of some of these projects would easily be able to cover the development of a small dedicated space telescope for a smaller version of the same instrument ( not necessarily a loss in capacity given the advantages of a space telescope ) … it’s not going to be the case for every single telescope project… some of the advanced robotically driven fibre optic spectroscopy instruments would be a bit more challenging given that motors in space aren’t as simple as on the ground (lubricants, heat dissipation and all that) but there’s a lot of other work that could “make the jump” and I expect will make the jump once the cost comes down… there’s whole fields of astronomy that are in a tough spot because of atmospheric absorption, notably ultraviolet astronomy, and they’ve eagerly been producing mission concepts for decades.

JohnFen 4y ago

We don't want all telescopes to have to be in orbit, though. That would raise the cost of astronomy enormously. Most astronomy is done with ground-based telescopes for pretty solid reasons.

ricardobeat 4y ago
A temporary problem, if cost per kg for launches comes down as predicted in the next few years.
- JohnFen 4y ago
  I have doubts. Launch costs aren't the only thing that makes space-based telescopes very expensive.
  - techdragon 4y ago
    Having spent the time working on a space telescope design (Worked on making a cubesat amateur telescope during COVID lockdowns) it’s a significant driver of secondary costs beyond the primary “launch cost”. Space telescopes are commonly “volume constrained” not “mass constrained” like how only Ariane 5 had a fairing big enough for the James Web Space Telescope, how Hubble was as big as they could fit in the Shuttle cargo bay, and many other “big science” general purpose “an observatory in space” sort of telescopes end up expanding to fit their launch volume because the main structures are “empty tubes” or folding mirrors, or extending booms (X-ray telescope mirrors are super clever things) and so you end up with everything else around these low density telescopes structures having heaps of mass budget… but then your still looking at vibrations, ruggedness requires mass… and so the circular game of musical chairs with engineering constraints begins… and you do a lot of engineering work to keep your mission on track. With major reduction in launch costs it becomes a lot more practical to launch smaller more specifically focused telescopes like we’ve seen with Kepler, TESS and CHEOPS, there’s commercial suppliers of professional grade telescopes, which are more than enough for useful research and with ample spare launch mass they could be given the same kind of cushy ride to space that the commercial cameras you see on the ISS got… it’s a bit of work to vacuum rate something but it would be less work than a camera by far given the fewer moving parts… and so then it’s just your instruments… with lower launch costs you can get significantly better science. Astronomical grants routinely cover the development of new instruments for ground based telescopes, and the costs of some of these projects would easily be able to cover the development of a small dedicated space telescope for a smaller version of the same instrument ( not necessarily a loss in capacity given the advantages of a space telescope ) … it’s not going to be the case for every single telescope project… some of the advanced robotically driven fibre optic spectroscopy instruments would be a bit more challenging given that motors in space aren’t as simple as on the ground (lubricants, heat dissipation and all that) but there’s a lot of other work that could “make the jump” and I expect will make the jump once the cost comes down… there’s whole fields of astronomy that are in a tough spot because of atmospheric absorption, notably ultraviolet astronomy, and they’ve eagerly been producing mission concepts for decades.