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 o

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.