The distance between the craft after flight 70 was 924.05 meters, flight 71 was only 71.0 meters (a lot less than planned), but we don't have the coordinates from JPL yet. It was supposed to fly West, so we can estimate the emergency landing was west of the rover, so the distance would be just shy of 1 kilometer. Flight 72 was supposed to be a pop up flight (up and down) to re-establish its coordinates etc. The helicopter and rover are at roughly the same elevation (0.6 meters difference) but there is a large levee between them (no direct line of sight). The rover would likely have to drive ~500 meters (or more) before it could image the helicopter from a safe location, as it would be unlikely to drive into the old river channel the helicopter is in now (too much dangerous sand)