[lionkor]

The more general version of that question would be: Whats the closest distance it can focus to?

[TeMPOraL]

Isn't this an interferometer? As in, compensating for lack of focus with lots of math and some clever assumptions? I don't think you can operate it in reverse the way you can with a single optical/radio system.

[magicalhippo]

Isn't that the entire point behind phased arrays[1]?

[1]: https://en.wikipedia.org/wiki/Phased_array

[jojobas]

GPS and some geostationary satellites should be possible, LEO not so much as they'd be below the horizon for at leas half of the array.