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There are some hard, unforgiving physical limits on resolution of photographs from orbit, even with digital correction of the images. For one thing, the camera

There are some hard, unforgiving physical limits on resolution of photographs from orbit, even with digital correction of the images. For one thing, the camera is necessarily far away, and moving fast at the same time.[1] I was able to follow the specific link just kindly submitted here, which of course shows a rather large object (a commercial airliner). The satellite company's image gallery[2] compares quite favorably in resolution to an earlier company's image gallery we discussed here on HN about three years ago. But it will be quite a while--perhaps never--before some of the statements about satellite imagery that were already being made for propaganda purposes in the 1960s will be anything close to reality, even for classified military intelligence satellites. We won't be reading people's mobile phone screens from orbit ever, probably. Unmanned drone aircraft are at nearer distance and travel at slower speed, and provide a much better platform than earth-orbiting satellites for high-resolution spying. [1] http://books.google.com/books?id=6DBnS2g-KrQC&pg=PA204&lpg=PA204&dq=Physics+for+Future+Presidents+spy+satellite+resolution http://books.google.com/books?id=6DBnS2g-KrQC&pg=PA204&lpg=P... http://www.kmc63.com/phy1000/worksheet-licenseplates.pdf http://www.kmc63.com/phy1000/worksheet-licenseplates.pdf [2] http://www.firstimagery.skybox.com/ http://www.firstimagery.skybox.com/

claar 13y ago
We've been overcoming hard, unforgiving physical limits for ages. The obvious solution in this case is to combine images from multiple satellites, ala http://en.wikipedia.org/wiki/Very_Large_Telescope http://en.wikipedia.org/wiki/Very_Large_Telescope
- mturmon 13y ago
  Yes. It would be unwise to assume that space-based optical interferometry is not currently being done.
bane 13y ago
The first link you provided also brings up several interesting implications about continuous surveillance from space. The first is that it is technically possible, but economically difficult. Getting ~5000 high resolution satellites in LEO is not really all that much more difficult than getting 1, it's a matter of scale. But getting funding to put that number up is virtually impossible. Even smallsats and other swarm approaches lack the physical space for the sensors (which is limited by physics, not technology). This is why air breathing drones are becoming so important. Make no mistake, NASA continuous aircraft programs like Helios have ready applications in surveillance. And from those heights, the sensors don't have to be nearly as large as on an LEO bird. The second is that receiving data from that many birds is problematic. There are only so many receiving stations and only so much EM bandwidth available for communication and recovery of the images. Even switching to drones doesn't solve the problem. Even as of last year bandwidth was a limiting factor for the number of drones up in the air at once. [1] So now we have two problems, getting birds in the air, and we still have the bandwidth problem for downlink. Finally, analyzing that much imagery is nearly impossible. Automated algorithms help some with certain tasks, but storage, processing, accessing, then analyzing all of that on a continuous basis is pretty much impossible. So even if getting enough sensors deployed is solved, and getting bandwidth is solved, it doesn't mean there's enough people to physically look at and interpret the results anyway. And storing all that for later instantaneous on-demand retrieval is still a problem nobody's really solved. 1 - http://www.defensenews.com/article/20130331/DEFFEAT02/303310009/Pentagon-Seeks-Solutions-UAV-Bandwidth-Crunch http://www.defensenews.com/article/20130331/DEFFEAT02/303310...
- JoeAltmaier 13y ago
  Bandwidth issues are alleviated by directional antennae, right?
  - toomuchtodo 13y ago
    http://en.wikipedia.org/wiki/Spot_beam http://en.wikipedia.org/wiki/Spot_beam
  - bane 13y ago
    Not necessarily, you still need to collect the transmission. You can still saturate a frequency no matter how focused if enough transmitters are hitting the same receiver.
    - ajcarpy2005 13y ago
      Exactly. So just deploy enough receivers and focus the transmissions enough so that the frequencies don't get saturated.
      - JoeAltmaier 13y ago
        Or the receivers track the satellites. This can be done electronically, no need for swivels and servos, just an array.
deleted 13y ago
[deleted]
mxfh 13y ago
The Skybox link has 2 great videos (footage is mostly the same, one is edited with "need more crosshairs"), for those who haven't seen them yet. http://www.firstimagery.skybox.com/hd-video/2014/2/11/looking-down-from-600-km-above-the-earths-surface-with-hd-video http://www.firstimagery.skybox.com/hd-video/2014/2/11/lookin... youtube/ vimeo direct: http://www.youtube.com/watch?v=fCrB1t8MncY&hd=1 http://www.youtube.com/watch?v=fCrB1t8MncY&hd=1 https://vimeo.com/82644547 https://vimeo.com/82644547 http://www.youtube.com/watch?v=BsW6IGc4tt0&hd=1 http://www.youtube.com/watch?v=BsW6IGc4tt0&hd=1 https://vimeo.com/86196806 https://vimeo.com/86196806

claar 13y ago

We've been overcoming hard, unforgiving physical limits for ages. The obvious solution in this case is to combine images from multiple satellites, ala http://en.wikipedia.org/wiki/Very_Large_Telescope http://en.wikipedia.org/wiki/Very_Large_Telescope

mturmon 13y ago
Yes. It would be unwise to assume that space-based optical interferometry is not currently being done.

bane 13y ago

The first link you provided also brings up several interesting implications about continuous surveillance from space. The first is that it is technically possible, but economically difficult. Getting ~5000 high resolution satellites in LEO is not really all that much more difficult than getting 1, it's a matter of scale. But getting funding to put that number up is virtually impossible. Even smallsats and other swarm approaches lack the physical space for the sensors (which is limited by physics, not technology). This is why air breathing drones are becoming so important. Make no mistake, NASA continuous aircraft programs like Helios have ready applications in surveillance. And from those heights, the sensors don't have to be nearly as large as on an LEO bird. The second is that receiving data from that many birds is problematic. There are only so many receiving stations and only so much EM bandwidth available for communication and recovery of the images. Even switching to drones doesn't solve the problem. Even as of last year bandwidth was a limiting factor for the number of drones up in the air at once. [1] So now we have two problems, getting birds in the air, and we still have the bandwidth problem for downlink. Finally, analyzing that much imagery is nearly impossible. Automated algorithms help some with certain tasks, but storage, processing, accessing, then analyzing all of that on a continuous basis is pretty much impossible. So even if getting enough sensors deployed is solved, and getting bandwidth is solved, it doesn't mean there's enough people to physically look at and interpret the results anyway. And storing all that for later instantaneous on-demand retrieval is still a problem nobody's really solved. 1 - http://www.defensenews.com/article/20130331/DEFFEAT02/303310009/Pentagon-Seeks-Solutions-UAV-Bandwidth-Crunch http://www.defensenews.com/article/20130331/DEFFEAT02/303310...

JoeAltmaier 13y ago
Bandwidth issues are alleviated by directional antennae, right?
- toomuchtodo 13y ago
  http://en.wikipedia.org/wiki/Spot_beam http://en.wikipedia.org/wiki/Spot_beam
- bane 13y ago
  Not necessarily, you still need to collect the transmission. You can still saturate a frequency no matter how focused if enough transmitters are hitting the same receiver.
  - ajcarpy2005 13y ago
    Exactly. So just deploy enough receivers and focus the transmissions enough so that the frequencies don't get saturated.
    - JoeAltmaier 13y ago
      Or the receivers track the satellites. This can be done electronically, no need for swivels and servos, just an array.

deleted 13y ago

[deleted]

mxfh 13y ago

The Skybox link has 2 great videos (footage is mostly the same, one is edited with "need more crosshairs"), for those who haven't seen them yet. http://www.firstimagery.skybox.com/hd-video/2014/2/11/looking-down-from-600-km-above-the-earths-surface-with-hd-video http://www.firstimagery.skybox.com/hd-video/2014/2/11/lookin... youtube/ vimeo direct: http://www.youtube.com/watch?v=fCrB1t8MncY&hd=1 http://www.youtube.com/watch?v=fCrB1t8MncY&hd=1 https://vimeo.com/82644547 https://vimeo.com/82644547 http://www.youtube.com/watch?v=BsW6IGc4tt0&hd=1 http://www.youtube.com/watch?v=BsW6IGc4tt0&hd=1 https://vimeo.com/86196806 https://vimeo.com/86196806