Khai-J-Bach posted at 4:55PM Sun, 12 November 2017 - #4317843

While there is no atmosphere to reflect, the MOON itself does. Remember, moonlight? ...

The same happens on sunny days on earth :: light re-reflected, as when ray-tracing with 3 or 4 bounces is allowed in Poser. The sunlight would also have bounced back from the near side of the crater and lit up the part of the crater bottom which in the photo is dark. Did the photographer shine a bright light on the astronaut? :: see the bright spot in the reflection on his helmet faceplate.