Lunokhod 1 stopped answering in 1971 and nobody could find its laser reflector again until 2010, when a photograph from orbit showed where the rover had parked.

Its twin, Lunokhod 2, had been ranged for decades. The first rover's last position was known only to within a few kilometres, which is far too coarse to aim a laser at. Once an orbital image narrowed it down, the very first attempt got a return signal stronger than any other reflector on the Moon — it happens to sit at a useful angle.