Could a small curved mirror and/or lens in Earth's orbit be aimed at a different hemisphere from where you are be be viewed with a powerful telescope to see the ground through the mirror? Would a more powerful telescope than the Hubble see more or less because of the atmosphere diffracting light twice?

Bonus: Would sending a mirror to space cost less this way then a huge camera/telescope?

  • $\begingroup$ This Requires to send a giant mirror in orbit which is hard then develop a such powerful Telescope (that's hard too) to see our selves. We would get noisy,blurred images due to the atmosphere (More Light will be scattered as it has to pass through atmosphere twice). instead its easy to just send a telescope in orbit. Which would provide more better images. $\endgroup$
    – user24215
    Sep 7, 2018 at 13:01

1 Answer 1


If I interpret your system concept, you want to view over the horizon (OTH) by adding a distant mirror to your overall telescope optical prescription.
First: it's not necessary to go into orbit, depending on how far OTH you want to view.
Second, whether you try to place such a mirror on, e.g., a blimp or in orbit, the difficulties involved in launching, aiming, stabilizing, etc. a mirror of sufficient size to allow enough light-gathering at your ground location are greater than the difficulty in launching a spy satellite (of which there are many, each with a telescope comparable to Hubble's main scope).

Third, for optical reasons (try googling "shower-curtain effect adaptive optics") viewing the ground from orbit suffers far less from atmospheric distortion effects than vice versa. Far better to put the telescope in orbit and send digitized image data to the ground.


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