THE DETAILS: Over the course of the four decades since the Apollo crewed landings, the Moon has been visited and mapped in progressively greater detail by uncrewed probes sent by China, India, Japan and the United States. Some of these spacecraft are currently in operation in orbit around the Moon, sending fresh images and science data.
The 1994 Clementine probe, launched by NASA, was able to image a patch of differently reflective soil exactly where NASA said that Apollo 15’s LM had landed. This is compatible with the soil color changes expected as a consequence of the displacement of surface dust and the exposure of differently-colored underlying rock caused by a spacecraft rocket motor.
The same site was photographed in more detail in 2008 by the Japanese Kaguya probe (Figure 7-7), in 2009 by India’s Chandrayaan-1 and in 2012 by the Chinese Chang’e-2 spacecraft, confirming the Clementine findings and revealing a dot at the center of the patch: presumably, the descent stage of the Apollo 15 LM or its shadow.
Figure 7-7. The bright halo is located where Apollo 15 landed. Credit: JAXA/Selene.
Kaguya also performed altimetric measurements of the Moon, generating a 3D terrain map that matches exactly the terrain shown in the Apollo photographs.
In 2009 the United States’ Lunar Reconnaissance Orbiter (LRO) became the first probe to image directly the Apollo vehicles as well as the science experiments, the lines of footprints of the astronauts and the wheel tracks made by their electric car. Its first pictures were released in July 2009; some are shown in Chapter 3.