The Apollo 16 landing crew of Charles Duke and John Young touched down in the Descartes highland region on April 20, 1972. They discovered magnetic Moon rocks, which surprised scientists because the Moon does not now have a magnetic field. Even more surprising, the rocks' polarity varied, with some pointing up and some down. That indicated the Moon at one time might have had a molten core with a magnetic field that flipped from north to south.
In the command module, Ken Mattingly used sensor equipment to discover that the Descartes region was rich in aluminum. This raised hopes that local materials might some day be used to build lunar colonies. A return to the Moon must be based on extracting metals, oxygen and fuel from the lunar regolith (loose soil) to support exploration and colonization. This approach is the only affordable way to maintain a long-term presence away from Earth.
Duke attempted to set an Olympic high-jump record during the team's second surface excursion. But the jump almost was fatal when his backpack shifted during the leap, causing Duke to fall when he came back down. The suit didn't rupture when he hit, but Duke realized the jump could have been disastrous.
