Apollo 12 was the second crewed mission to land on the moon. The mission lifted off on Nov. 14, 1969, a little less than four months after two members of the Apollo 11 crew became the first people to walk on the moon. The target for Apollo 12 was a large basaltic plain on the moon's surface called the Ocean of Storms. Like its predecessor mission, the primary goal for Apollo 12 was to explore the area and prepare for future landing missions.

The Apollo 12 mission had several memorable moments, the first of which was landing on target. That didn't happen during Apollo 11, in part because Commander Neil Armstrong needed to steer around boulders on the surface to find a safe landing spot. Some accounts also claim that excess oxygen in the hatch between the spacecraft pushed Apollo 11's lunar lander (or lunar module) off course when it undocked from the command module.

The Apollo 12 mission is also remembered for surviving two lightning strikes during launch and for the strong camaraderie of its three astronauts, who were close friends before they were selected as a crew.

Prior to joining NASA in 1962, Cmdr. Pete Conrad graduated from Princeton University and joined the U.S. Navy, where he was a flight instructor. He took his first space flight on Gemini 5, in 1965, which set an endurance record at the time (eight days in space). That mission also pushed the U.S. ahead of the Soviet Union in accumulated hours in space. Conrad additionally commanded the Gemini 11 mission in 1966. After Apollo 12, he commanded the first mission to space station Skylab, in 1973, and participated in several tricky spacewalks to restore the space station, which was badly damaged at launch.

Lunar module pilot Alan Bean was a student of Conrad's at the U.S. Naval Test Pilot School before joining NASA in 1963. One of his first assignments for NASA was to work on missions after the moon landings. In interviews for journalist Andrew Chaikin's 1994 book "A Man on the Moon" (Penguin, 2007), astronauts said that Bean was Conrad's first pick for Apollo 12, but C.C. Williams, a rookie astronaut, earned the spot instead. Tragically, Williams died when his Northrop T-38 Talon supersonic jet crashed on Oct. 5, 1967. Conrad again asked NASA to bring Bean on board, and the agency agreed. Bean went on to command the second Skylab mission, in 1973.

The command module pilot for Apollo 12 was Richard "Dick" Gordon, who came to NASA in 1963 after setting flight speed and distance records and performing test flights for the Navy. His skill in the pilot's chair came in handy for the Gemini 11 mission, when he and Conrad piloted the docked spacecraft to 853 miles (1,373 km) above Earth, an altitude record at the time. Apollo 12 was Gordon's last spaceflight.

Lightning struck Apollo 12's rocket, a Saturn V, twice during the launch. While the astronauts had some trouble with the displays on board after the lightning strikes, the rocket remained functional and placed the spacecraft in its target orbit around Earth. NASA carefully evaluated the risks of the mission after the lightning strikes, and decided it was safe enough to proceed to the moon. (Several biographies say the agency later revised the launch safety rules to protect future spacecraft from lightning strikes.)

The command module, Yankee Clipper, and lunar module, Intrepid, safely arrived at the moon on Nov. 18. As planned, Gordon remained behind in Yankee Clipper while Conrad and Bean went into Intrepid for their trip to the lunar surface. During landing, Conrad and Bean anxiously looked outside, hoping that what they saw on the surface would correspond with what they had memorized from maps while back on Earth. When Conrad spotted a familiar crater, he whooped, "There it is! Son of a gun, right down the middle of the road!"

The planned landing point was too rocky for Conrad's taste, so he took the command stick in hand and carefully steered to an alternate landing site.

Intrepid's descent stirred up a large dust cloud on the lunar surface as the astronauts glided into the Ocean of Storms. Conrad landed with little fuel to spare, and within shouting distance of Surveyor 3, a robotic spacecraft that had landed on the moon more than two years earlier.

When it was time for Conrad to head down the ladder to the surface a few hours later, he joked about his height (5 feet, 6 inches tall, as opposed to Neil Armstrong's 5 feet, 11 inches): "Whoopee! Man, that may have been a small one for Neil, but it's a long one for me."

Surveyor 3 gets a visit from the Apollo 12 crew in 1969.
Surveyor 3 gets a visit from the Apollo 12 crew in 1969.
Credit: NASA

The crew faced problems as their first spacewalk progressed. Bean fried the video camera lens when he accidentally pointed it toward the sun, leaving the mission with no way to record usable live video."Don't come to the moon without a hammer"

Then, Conrad struggled with deploying a nuclear-powered experiment package; he couldn't free the plutonium cask from its case. When repeated attempts proved unsuccessful, Conrad reluctantly tried hitting the package with a hammer. The fuel element sprang free, and Bean quipped, "Don't come to the moon without a hammer."

Bean and Conrad spent the night in hammocks inside the lunar module. The next morning, the astronauts collected geological samples.

The astronauts hiked in a large circle, making stops at various sites to gather samples. Bean and Conrad also experimented with new sampling techniques and retrieved pieces of Surveyor (such as the TV camera and electrical cables) to take back to Earth for scientific analysis. To the astronauts' surprise, Surveyor was coated with dust kicked up from Conrad's landing, which happened about 656 feet (200 m) away.

Bean and Conrad lifted off the next day to meet Gordon and head back to Earth. The three splashed down in the Pacific Ocean on Nov. 24, about 3 miles (5 km) from the target area. The flight had lasted 244 hours, 36 minutes, 25 seconds — just 62 seconds longer than planned. The "Pinpoint Mission," as Apollo 12 was called, had demonstrated how future space missions could be executed with high precision.

The Yankee Clipper is on display at the Virginia Air & Space Center in Hampton, Virginia. Intrepid's upper stage, which carried the astronauts back to Yankee Clipper, no longer exists, as it crashed into the moon on Nov. 20, 1969. Apollo 12's 50th anniversary is in 2019.

The Apollo 12 crew, who were close friends, were always disappointed that Gordon never got the chance for a moonwalk. Years later, Bean — in his next career, as an artist — did a painting portraying Gordon, Bean and Conrad on the surface of the Ocean of Storms. Bean titled the piece "The Fantasy," one of a series of paintings showing "buddies forever" on the moon.

NASA flew five more crewed missions to the moon from 1970 to 1972, with four of those crews making it to the surface as planned. (Apollo 13 was safely aborted due to severe mechanical issues.) The agency next turned its attention to near-Earth science, principally through the space shuttle program and the International Space Station.

In 2017, President Donald Trump's administration directed NASA to send humans to the moon in the coming decade, before sending astronauts to Mars. NASA is also working on a concept for a crewed space station, called the Lunar Orbital Platform-Gateway, as well as the Orion spacecraft, designed for long-distance voyages.