Bean followed, and the astronauts accomplished a great deal scientifically during their two moonwalks. The second took place 11 hours after the end of the first and lasted about 3 hours 50 minutes. During this trip, Conrad and Bean walked over to the Surveyor 3 craft and disassembled pieces of the spacecraft, removing 22 pounds (10 kilograms) of material to take back to Earth, including the probe’s camera. After the camera was analyzed back on Earth, reports circulated that it contained live bacteria called Streptococcus mitis. Finding this common bacterium puzzled NASA researchers. At first the agency claimed that the camera had not been properly sterilized before being sent on the Surveyor 3 mission, saying that the bacteria had survived a trip from Earth to the Moon and back again. However, NASA later reversed its position, changing the explanation to contamination by workers who examined the camera after its return to Earth: The camera came back in a porous bag, workers had their bare arms exposed as they examined the camera, and other sloppy procedures had been employed.
The experiments performed by Conrad and Bean set the stage for more complex science on the remaining Apollo missions. They set up the first Apollo Lunar Surface Experiments Package, a collection of sensors that would relay long-term data about the Moon back to Earth. The astronauts measured the lunar magnetic field, collected seismic data, and observed the solar wind. Conrad and Bean also carried the first color TV camera onto the Moon, attempting to increase the quality of television transmission back to Earth substantially. But when Bean carted the camera to a position near the LM and began to set it up, he accidentally pointed the lens toward the Sun, destroying the camera’s primary tube and thus ending the TV coverage of the mission right away.
As with all lunar missions, the astronauts collected a substantial number of Moon rocks. Analysis of the first returned sample indicated the rocks were far more similar to Earth rocks than had been previously believed. The similarities remained a mystery for a time, and ultimately led to a stunning hypothesis about the origin of the Moon. (See “The Moon’s violent origin,” page 44.) The astronauts also took large numbers of photographs, although Bean accidentally left some behind when he departed, so exposed rolls of Apollo 12 film still sit on the Moon’s surface today.
Successful return
After their second moonwalk, Conrad and Bean rested in the LM. On November 20, they ignited the ascent engine, which pushed them upward to dock with Gordon in the CM once again. For the second time, humans left the Moon behind. The LM’s ascent stage dropped away after docking, where the seismometers left on the lunar surface recorded vibrations from its impact that lasted for more than an hour. The trio of astronauts spent a day taking pictures of the Moon’s surface from orbit before heading for home.
On the way back, Apollo 12 marked another first when the crew witnessed an eclipse of the Sun by Earth from their spacecraft windows. They splashed down in the Pacific Ocean on November 24, east of American Samoa. During splashdown, one of the astronauts’ film cameras fell, striking Bean in the head — knocking him briefly unconscious and causing a mild concussion.
The crew was recovered by the USS Hornet, returned to the United States as heroes, and the successful mission made the statement that the Apollo program, and repeated trips to the Moon, were here to stay.