Photos of a KH-12 Kennan Keyhole Secret Military Spy Satellite (2013)

In 20 years Google Maps will probably show live video, at least in major cities.

This is actually something that can be pretty safely ruled out. Spy satellites like this are placed at very low orbits, which allows them to get very high resolution images. At these low orbits, the satellites are moving incredibly fast relative to the ground. They're circling the earth in 1 to 2 hours. This is advantageous since the same satellite can be used to observe different areas and with minimal maneuvering can make passes over a much wider area than they could see in a single orbit, and even follow slow moving targets like fleets of ships or army columns, but it also means that they are only observing any particular place on earth for a very brief interval with substantial periods of time in between. While you could see the timelapse of say a building being constructed, they can't make high resolution videos of things that take more than a few seconds and less than several hours. To get continuous imaging in a particular spot, you need to utilize a very different orbit that will take the satellite much further away from Earth, which ruins the resolution of any imaging. While the exact resolution of a given satellite is classified, the laws of physics put upper bounds on how good an image they can possibly get. Any satellite that could track and record a specific individual for an extended period of time would be way too large to launch.

This is fascinating. From an original source in that article:

> The Regiment 58 Engineers had learned a lot since 1995 about how to avoid detection by U.S. spy satellites. A lot of work was done at night, and heavy equipment was always returned to the same parking spot at dawn so that image analysts would conclude that they had never moved. Piles of sand were shaped to mimic the wind-aligned and shaped dune forms in the area. When cables were laid they were carefully covered and native vegetation replaced to conceal the digging.

If the X-37 has anti-satellite capabilities, it's probably nothing like the Chinese ASATs. Satellites are very fragile, and it would be very easy to disable one by punching a hole in a heat-shield or cooling system. The X-37 could also place small sabotage tools on or near adversary satellites, for future activation in the event of a conflict.

The mirror size is largely limited by the size of the vehicle launching the satellite into space, if I recall correctly.