The majority of the second moonwalk was dedicated to reaching the rim of Cone Crater. The wide, deep geological gold mine, which scientists believed was actually the remains of an ancient volcano.
With the Hycon camera down, Roosa would have to step in and use a Hasselblad with a 500 mm lens, to take detailed photos of the Apollo 16 potential landing site. If Roosa did nothing else, he had to return to earth with pictures of Descartes that would be good enough to plan a lunar landing.
The mortar package contained a set of grenades which were planned to be fired to distances of 500, 1000, 3000, and 5000 feet to the north of the ALSEP site.
A small plutonium source was used to power the Radioisotope Thermoelectric Generator (RTG) that would provide electric power for the ALSEP experiments. Ed Mitchell performed the delicate maneuver of inserting the fuel capsule into the RTG.
“Al is on the surface. And it’s been a long way, but we’re here.” Alan Shepard
Suddenly the caution lights went out and the radar signals began to transmit. Within seconds the astronauts could see that its data was good. Seconds later in mission control, a jubilant Will Presley shouted, “Flight, we got radar lockup!”
While checking the lander’s guidance software, during a final practice run for the landing, engineers in mission control detected that the computer was receiving an errant signal from the abort pushbutton.
The first extended use of the Service Propulsion System engine on the Command and Service module was for the Lunar Orbit Insertion (LOI) burn.