First time human explorers met up with a robotic spacecraft in space
First crewed lunar mission with science as the primary objective
Launch: Nov. 14, 1969
Lunar Orbit Insertion: Nov. 18, 1969
Lunar Landing: Nov. 19, 1969
Lunar Surface Departure: Nov. 20, 1969
Recovery on Earth: Nov. 24, 1969
With Apollo 12, the program’s primary goal moved beyond landing humans on the Moon and returning them safely to Earth. This was the first Apollo mission with science at the forefront of its objectives. It succeeded in ways both anticipated and completely unexpected.
On Nov. 19, 1969, while Richard F. Gordon piloted the command module “Yankee Clipper” in lunar orbit, Apollo 12 Commander Charles P. "Pete" Conrad and Alan L. Bean, pilot of the lunar module “Intrepid,” flew down to Oceanus Procellarum (Ocean of Storms). This was to be the first demonstration of “point landing,” the ability to target a landing site with a fair amount of precision. NASA hoped that they would be able to land within a mile (1.6 kilometers) of Surveyor 3, a robotic spacecraft that, in April 1967, had made one of the first soft landings on the Moon. Conrad and Bean surpassed expectations by landing within just 512 feet (156 meters) of the defunct spacecraft.
The Surveyor Surprise
The choice of Surveyor 3 as the landing target had been the subject of dispute. Opponents pressed for a landing site they thought would be more scientifically interesting. Advocates argued that it would be valuable to bring back parts of the spacecraft so scientists and engineers could see the effect of more than two and a half years of exposure to lunar conditions. They also cited the value of bringing samples from the site to Earth-based labs in order to validate data that the spacecraft had radioed to Earth.
No one suspected that Surveyor 3 would provide evidence about the possibility of life on other worlds.
Among the Surveyor 3 components that the Apollo 12 astronauts returned to Earth was a TV camera. On the insulation covering the circuit boards were 50 to 100 Streptococcus mitis, a harmless kind of bacteria commonly found in human noses, mouths and throats. They had traveled with Surveyor 3 to the Moon and spent two years and seven months in vacuum, subjected to harsh radiation, temperatures down to 20 degrees above absolute zero, and utter lack of water or nutrients. But they had survived, and when scientists reintroduced them to a nutrient source, they resumed their biological activities.
Apollo 12 Commander Pete Conrad said, “I always thought the most significant thing that we ever found on the whole ... Moon was that little bacteria who came back and lived.”
While this doesn’t prove that there is life anywhere else in the universe, it does demonstrate the possibility that life could exist under conditions far less hospitable than those of Earth. And astrobiologists who speculate that life might have arisen elsewhere and been transplanted to Earth by meteorites no longer have to worry about claims that living things could not survive the journey through space.
Exploring the Moon
Conrad and Bean conducted two moonwalks totaling nearly eight hours, during which they deployed the Apollo Lunar Surface Experiments Package (ALSEP), a more comprehensive collection of experiments than the one that Apollo 11 had delivered. They also took photographs, investigated lunar soil mechanics and collected samples of rocks and regolith (the pulverized rock that constitutes lunar soil) and particles from the solar wind. To provide information about the lunar interior, they collected samples along the rays of large craters, which consist of material ejected from deep below the lunar surface by the crater-forming impacts. The information Apollo 12 provided caused scientists to rethink virtually all of their theories about the Moon’s origin.
Between moonwalks, the astronauts enjoyed an upgrade over the accommodations in Apollo 11’s lander: hammocks and blankets.
Between moonwalks, the astronauts enjoyed an upgrade over the accommodations in Apollo 11’s lander: hammocks and blankets. Altogether, they were on the lunar surface for 31 hours, 31 minutes, of which nearly 8 hours were spent outside the lunar module – three times as long as the Apollo 11 astronauts. Conrad and Bean covered 0.84 mile (1.35 kilometers) on foot.
They lifted off from the Moon on November 20. After docking with Yankee Clipper in lunar orbit and transferring into it for the ride home, they jettisoned Intrepid and set it to crash into the lunar surface to calibrate the seismometer they had left there. It hit the Moon at a speed of 3,735 mph (1.7 kilometers per second), 47 miles (76 kilometers) from the instrument, creating the first artificial moonquake. The result was unlike anything experienced on Earth. The vibrations didn’t subside significantly for nearly an hour.
Apollo 12 splashed down in the Pacific Ocean on Nov. 24, 1969 at 20:58:24 UT (3:58:24 p.m. EST) near American Samoa, about four miles (seven kilometers) from the recovery ship USS Hornet, after a mission elapsed time of 244 hours, 36 minutes, 24 seconds.
- Credit: NASA