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>> optics are way better though That was going to be my question. Doesn’t the NRO need big optical lenses for their missions? Are there any “telescopic” advanc

>> optics are way better though That was going to be my question. Doesn’t the NRO need big optical lenses for their missions? Are there any “telescopic” advancements that can fit into small sats that can meet their mission objectives?

ChuckMcM 6y ago
Yes. My understanding of these things based mostly on trolling through the various digital imagery company websites, is that many of the small satellites can generate detail as good as the "big guys" (at least as far is known in open sources) by using a telescopic lens. The difference however is aperture. Given the size of the optics on a small satellite the amount of area it can cover at 1 meter per pixel resolution is much smaller than something with a very large aperture could. As a result if you take a 10 Mpixel image with 1 meter per pixel accuracy that is a region roughly 3.2km on a side. Not a particularly large area.
- bartwe 6y ago
  Do the small sats have an advantage by being closer to the target, needing less zoom?
  - xvedejas 6y ago
    Higher orbits are much more expensive to launch a satellite into. I think partially because of this, commercial imaging satellites will be in the range of 600-800km altitude unless there's a really good reason otherwise. So I don't think that distance would account for a very large factor.
  - Fordec 6y ago
    Yes. The difference between 100k-400km in LEO is far different from 22000km in GEO. Planet Labs updated their licenses for a few satellites a couple of months back to gain double digit percentage resolution quality increases by dropping the orbit (I think it was somewhere about by 50km to the lower end of that range) for example. The trade off is that you hit more atmosphere in that lower orbit and will reenter the atmosphere much sooner. So that increases the number of launches you need to do to replenish your fleet. Which is $$$. Also, they have greater relative velocities so require better targeting and command & control technology to compensate.
- garmaine 6y ago
  Nothing open source can take images anywhere near the capability of spy satellites. We learned this when Trump tweeted an image of the Iranian missile/launch vehicle disaster.
- LargoLasskhyfv 6y ago
  Maybe [1] https://en.wikipedia.org/wiki/Superlens https://en.wikipedia.org/wiki/Superlens & [2] https://en.wikipedia.org/wiki/Negative-index_metamaterial https://en.wikipedia.org/wiki/Negative-index_metamaterial can change that? Also I'm sometimes wondering what happened to Holography, and if something like [3] https://en.wikipedia.org/wiki/Invention_Secrecy_Act https://en.wikipedia.org/wiki/Invention_Secrecy_Act came into play?
  - Fordec 6y ago
    There's also rules on launching a satellite with capabilities below 10m per pixel on the basis of national security. At least if you're an American company anyway, can't vouch for elsewhere but they're a bit behind the tech curve (at least in the private sector) in this field (but not by much) so it hasn't really come up yet as an issue so far. There was an image that Trump tweeted a satellite image about something in Iran a while back, I forget the actual reason. But it was a declassified image of something and some keen eyed observers did some analysis on it and concluded the resolution was better than what is "Officially" out there. So it's safe to say there's better out there that we just don't know about yet.
    - LargoLasskhyfv 6y ago
      Rocket blew up on pad during launch. [1] https://www.thedrive.com/the-war-zone/29634/trump-tweets-intelligence-image-after-irans-rocket-explosion-and-offers-them-best-wishes https://www.thedrive.com/the-war-zone/29634/trump-tweets-int... Made me think of the movie "Enemy of the State" from 1998, and another action/sci-fi B-Movie from before 1980 which I can't remember the title anymore because forgettable, except of the FLIR inserts they made. Which were as good as anything you can personally buy today as private person. In a B-Movie! From before 1980! (Maybe even 1975/76) W-T-F? I really can't remember the title anymore, because "loading, looking, lösching!" (loading, watching, erasing)
chiph 6y ago
In 2012 the NRO turned over two satellites to NASA [0] for research purposes. The scientists who have examined them (they have not been launched yet) described them as being better than Hubble even though they are comparable in size (designed to fit in the Shuttle bay). Given the unlimited funds available to them, I expect they're a decade ahead of industry. The NRO is probably going for larger lenses in future satellites to increase their field of view. Could they use a series of smaller sats orbiting in a cluster to form a virtual lens, much like the multiple mirror telescope in Arizona [1]? Maybe. [0] https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O... [1] https://en.wikipedia.org/wiki/MMT_Observatory https://en.wikipedia.org/wiki/MMT_Observatory
- walrus01 6y ago
  To clarify what they turned over were lens and optics assemblies that are a sort of cousin to the hubble space telescope's structural body and lens, not whole satellites. No power systems, no control electronics, no batteries, no comm systems, etc.
- LargoLasskhyfv 6y ago
  Probably. At least it works for RADAR in [1] https://en.wikipedia.org/wiki/TerraSAR-X https://en.wikipedia.org/wiki/TerraSAR-X & [2] https://en.wikipedia.org/wiki/TanDEM-X https://en.wikipedia.org/wiki/TanDEM-X edit: optical [3] https://en.wikipedia.org/wiki/Sentinel-2 https://en.wikipedia.org/wiki/Sentinel-2 but with rather low resolution.
- namibj 6y ago
  There are proposals[0] for mirror-fleet based exoplanet detecting and imaging, as well as for resolving the purported 20 km neutron star seen/known as the Crab Pulsar. But accurately controlling such a swarm seem like a still-untested concept. [0]: https://www.researchgate.net/profile/Olivier_Lardiere/publication/228590727_Hypertelescope_imaging-_From_exo-planets_to_neutron_stars/links/56095f5a08ae1396914a120c/Hypertelescope-imaging-From-exo-planets-to-neutron-stars.pdf https://www.researchgate.net/profile/Olivier_Lardiere/public...
bleepblorp 6y ago
Ultimately, the diffraction limit means that--all else held equal--larger optics will always beat smaller optics for image quality. Any tricks used to aid small optical platforms will have as much, or more, of an improvement if applied to large optical platforms.

ChuckMcM 6y ago

Yes. My understanding of these things based mostly on trolling through the various digital imagery company websites, is that many of the small satellites can generate detail as good as the "big guys" (at least as far is known in open sources) by using a telescopic lens. The difference however is aperture. Given the size of the optics on a small satellite the amount of area it can cover at 1 meter per pixel resolution is much smaller than something with a very large aperture could. As a result if you take a 10 Mpixel image with 1 meter per pixel accuracy that is a region roughly 3.2km on a side. Not a particularly large area.

bartwe 6y ago
Do the small sats have an advantage by being closer to the target, needing less zoom?
- xvedejas 6y ago
  Higher orbits are much more expensive to launch a satellite into. I think partially because of this, commercial imaging satellites will be in the range of 600-800km altitude unless there's a really good reason otherwise. So I don't think that distance would account for a very large factor.
- Fordec 6y ago
  Yes. The difference between 100k-400km in LEO is far different from 22000km in GEO. Planet Labs updated their licenses for a few satellites a couple of months back to gain double digit percentage resolution quality increases by dropping the orbit (I think it was somewhere about by 50km to the lower end of that range) for example. The trade off is that you hit more atmosphere in that lower orbit and will reenter the atmosphere much sooner. So that increases the number of launches you need to do to replenish your fleet. Which is $$$. Also, they have greater relative velocities so require better targeting and command & control technology to compensate.
garmaine 6y ago
Nothing open source can take images anywhere near the capability of spy satellites. We learned this when Trump tweeted an image of the Iranian missile/launch vehicle disaster.
LargoLasskhyfv 6y ago
Maybe [1] https://en.wikipedia.org/wiki/Superlens https://en.wikipedia.org/wiki/Superlens & [2] https://en.wikipedia.org/wiki/Negative-index_metamaterial https://en.wikipedia.org/wiki/Negative-index_metamaterial can change that? Also I'm sometimes wondering what happened to Holography, and if something like [3] https://en.wikipedia.org/wiki/Invention_Secrecy_Act https://en.wikipedia.org/wiki/Invention_Secrecy_Act came into play?
- Fordec 6y ago
  There's also rules on launching a satellite with capabilities below 10m per pixel on the basis of national security. At least if you're an American company anyway, can't vouch for elsewhere but they're a bit behind the tech curve (at least in the private sector) in this field (but not by much) so it hasn't really come up yet as an issue so far. There was an image that Trump tweeted a satellite image about something in Iran a while back, I forget the actual reason. But it was a declassified image of something and some keen eyed observers did some analysis on it and concluded the resolution was better than what is "Officially" out there. So it's safe to say there's better out there that we just don't know about yet.
  - LargoLasskhyfv 6y ago
    Rocket blew up on pad during launch. [1] https://www.thedrive.com/the-war-zone/29634/trump-tweets-intelligence-image-after-irans-rocket-explosion-and-offers-them-best-wishes https://www.thedrive.com/the-war-zone/29634/trump-tweets-int... Made me think of the movie "Enemy of the State" from 1998, and another action/sci-fi B-Movie from before 1980 which I can't remember the title anymore because forgettable, except of the FLIR inserts they made. Which were as good as anything you can personally buy today as private person. In a B-Movie! From before 1980! (Maybe even 1975/76) W-T-F? I really can't remember the title anymore, because "loading, looking, lösching!" (loading, watching, erasing)

chiph 6y ago

In 2012 the NRO turned over two satellites to NASA [0] for research purposes. The scientists who have examined them (they have not been launched yet) described them as being better than Hubble even though they are comparable in size (designed to fit in the Shuttle bay). Given the unlimited funds available to them, I expect they're a decade ahead of industry. The NRO is probably going for larger lenses in future satellites to increase their field of view. Could they use a series of smaller sats orbiting in a cluster to form a virtual lens, much like the multiple mirror telescope in Arizona [1]? Maybe. [0] https://en.wikipedia.org/wiki/2012_National_Reconnaissance_Office_space_telescope_donation_to_NASA https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O... [1] https://en.wikipedia.org/wiki/MMT_Observatory https://en.wikipedia.org/wiki/MMT_Observatory

walrus01 6y ago
To clarify what they turned over were lens and optics assemblies that are a sort of cousin to the hubble space telescope's structural body and lens, not whole satellites. No power systems, no control electronics, no batteries, no comm systems, etc.
LargoLasskhyfv 6y ago
Probably. At least it works for RADAR in [1] https://en.wikipedia.org/wiki/TerraSAR-X https://en.wikipedia.org/wiki/TerraSAR-X & [2] https://en.wikipedia.org/wiki/TanDEM-X https://en.wikipedia.org/wiki/TanDEM-X edit: optical [3] https://en.wikipedia.org/wiki/Sentinel-2 https://en.wikipedia.org/wiki/Sentinel-2 but with rather low resolution.
namibj 6y ago
There are proposals[0] for mirror-fleet based exoplanet detecting and imaging, as well as for resolving the purported 20 km neutron star seen/known as the Crab Pulsar. But accurately controlling such a swarm seem like a still-untested concept. [0]: https://www.researchgate.net/profile/Olivier_Lardiere/publication/228590727_Hypertelescope_imaging-_From_exo-planets_to_neutron_stars/links/56095f5a08ae1396914a120c/Hypertelescope-imaging-From-exo-planets-to-neutron-stars.pdf https://www.researchgate.net/profile/Olivier_Lardiere/public...

bleepblorp 6y ago

Ultimately, the diffraction limit means that--all else held equal--larger optics will always beat smaller optics for image quality. Any tricks used to aid small optical platforms will have as much, or more, of an improvement if applied to large optical platforms.