With each successive mission astronauts spent longer on the Moon and explored a
wider area. On the final three missions, astronauts were able to explore
farther afield in a battery-powered Moon car, the Lunar Roving Vehicle (LRV), which was stored in the descent stage of the Lunar Module. Its wheels
were made of steel wire, so there was no chance of punctures, and its top speed
was 18 km/h (11 mile/h), achieved on the Apollo 17 mission.
Apollo 15’s landing site was the
On the edge – the Apollo 15 Lunar Rover at Hadley rille
most spectacular of the entire series, next to the winding Hadley Rille at the
foot of the Apennine mountains that border eastern Mare Imbrium. Astronauts
David Scott and Jim Irwin drove to the edge of Hadley Rille from where they saw layers of lava in its walls. Evidently, the rille itself
had been carved out by a later flow of lava. They also photographed what
appeared to be layers of stratified rock on the flanks of an outcrop called Silver Spur next to Mount Hadley Delta to their southeast.
The most famous sample they collected was a white-coloured, crystalline rock
dubbed the Genesis Rock by the media but catalogued more prosaically by NASA’s geologists as sample 15415. At first, this was thought to be a part of the original lunar crust, dating
back some 4.6 billion years. Later analysis showed that it was about 4.1
billion years old, not as old as hoped but still predating the formation of
Mare Imbrium.
Before leaving the surface, Scott performed an experiment to demonstrate Galileo
Galilei’s finding that objects of different mass fall at the same rate. Galileo himself
is supposed to have performed this experiment from the leaning Tower of Pisa
using two balls of different weight. Scott used a hammer and a falcon’s feather (Falcon being the name of their Lunar Module). Without air resistance, the
feather hit the surface at the same time as the hammer.
