Due to the great similarity with the surface of Mars, NASA tested its rovers here (find here photos and video).
We did not visit the valley, but in the evening went to watch the sunset at the viewpoint Mirador de Kari - Piedra del Coyote (S 22 55.002 W 68 15.222), which is located over the Moon valley. This is a popular place, a lot of tourists gather here every day. It can be reached by bicycle from San Pedro de Atacama (8 km). Although you need to go uphill.
Getting there: as part of an organized tour from San Pedro de Atacama. Either by car or by bicycle, go to this location S 22 56.118 W 68 13.956.