A second problem to be faced with a working time machine is one that involves the addition of movement through space. Matter in the universe takes up space, that is, it has length, width, and depth. These are the three dimensions all matter possess. There is also a fourth dimension. The dimension of time.
All matter exists in space and moves through time.
You move through space as you go through the day. The earth and the rest of the planets and their moons, moves through space as they circle the sun. The sun moves through space as it moves with the rest of the galaxy around the galactic center and, as you can imagine, the galaxy is moving through the universe. The computation of all this relative movement is crucial for the successful rendezvous of satellites with the planets and moons they are to observe. The orbits are not neat ellipses.