3 ms·

You're certainly right about the need to move the observer, but I suspect you're wrong about how hard it is relative to building a 150m optical telescope (the l

You're certainly right about the need to move the observer, but I suspect you're wrong about how hard it is relative to building a 150m optical telescope (the largest to-date is ~10m). Orbital mechanics is a pretty well understood thing, so figuring out how the earth will move over the next 20 hours isn't that tough. The rest is just making sure you're able to position the 1m receiver very precisely and move it around in a very controlled way. I'm no expert, but I suspect we've demonstrated both in one or more NASA missions already. Probably super-expensive, but less of a technical challenge than building a proper 150m optical telescope.

mabbo 4y ago
The math is easy, the delta-V is hard. There is a precise point the craft would need to stay at relative to the earth and the target. There aren't any stable orbits that keep a craft at precisely that position, which means you are firing engines for 20 hours straight. Remember, you don't stay in space unless you are either in a stable orbit, moving at many km/s, or you're firing engines to resist gravity's pull. A spacecraft to stay at this point for 20 hours would be massive, and 99.9% fuel tanks.
- jrumbut 4y ago
  Could you get anywhere by taking the image over multiple passes? Even though the first image wouldn't be ready for a long time, if you have a lot of targets then you could increase efficiency to something like a tolerable level.