4 ms·

Couldn't a satellite do basically the same thing hovering over a city?

• Retra 10y ago
  Satellites can't hover over cities unless they are near the equator.
  • dcposch 10y ago
    And even then, only in geosynchronous orbit, way too far away for photo surveillance. Spy satellites are in LEO and orbit the earth v roughly once an hour--they dont "hover" at all. (In fact, they're passing over the ground at ~10km per second, so they end up using very fancy tracking optics to prevent motion blur. The best can apparently image lines in a parking lot. And to top off the technological insanity, some built during the Cold War did all this with ANALOG FILM, which was then dropped via a reentry capsule and caught in midair by a support plane while parachuting back to earth.)
  • beisner 10y ago
    But you could probably put a couple of satellites in Molniya-esque orbits and have near-24/7 imaging coverage of a location
    • obmelvin 10y ago
      Yes, it's far cheaper to fly planes in the atmosphere than launch satellites into space. And you only need one plane vs multiple satellites for persistence over a location.