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Apollo-12: A long step for a man

Anatoly Zak, Spaceflight Correspondent
Jan 10, 2016, 17:34 UTC

Sen—The historic lunar landing in July 1969 fulfilled the political goal of the Apollo program, but it barely began the exploration of the Moon.

Now, after the success of the first landing attempt, the Apollo-12 mission could focus on scientific tasks and expand the activities on the Moon.

The crew of Apollo-12 included the commander Charles (Pete) Conrad, command module pilot Richard Gordon and lunar module pilot Alan Bean. Conrad and Bean were meticulously trained for two four-hour excursions onto the lunar surface instead of just one short sortie in Apollo-11. In a special trunk attached to the descent stage, Apollo-12 carried a full-complement of scientific experiments to be deployed on the surface and collectively known as ALSEP, for Apollo Lunar Surface Experiments Package.

Also, the lessons of the first risky descent of Apollo-11, which took the lunar module miles away from the planned touchdown site, prompted mission managers to try a high-precision landing during the second expedition. It was decided to land Apollo-12 within walking distance from the long-dead Surveyor-3 probe, which made a soft landing in the Ocean of Storms on April 20, 1967.

Finally, with much more confidence in the reliability of Apollo's propulsion system, flight managers approved a more desirable trajectory between the Earth and the Moon, which would no longer guarantee the automatic return back to Earth without orbit corrections.

The seventh Saturn-5 rocket carrying the Apollo-12 mission lifted off from Cape Canaveral on Nov. 14, 1969, into heavily clouded sky and heavy rain. Slightly more than half a minute into the flight, the giant vehicle experienced a massive lightning strike, causing circuit breakers to shutdown major systems onboard Apollo-12 and numerous alarms to flash in the cockpit. A few seconds later, more lightning apparently hit.

Fortunately, the rocket remained on its normal course to orbit and the well-trained crew kept its cool, quickly re-starting the systems and restoring the flow of telemetry to mission control.

While the third stage of Saturn-5 and Apollo-12 were orbiting Earth, Houston re-confirmed that no permanent damage had been done to the spacecraft and gave the green light for the trip to the Moon. There was a lingering concern that the lightning could have disabled the parachute system in the command module, but an early return home could not save the crew in that case.

The rest of the flight to the Moon was uneventful and on the fifth day of the mission, the Intrepid lunar module separated from the Yankee Clipper command and service module in lunar orbit. Around 15 kilometers above the lunar surface, the Interpid fired its engine to begin its final descent.

At an altitude of 200 meters, Gordon switched to manual control with a good view of the landing area. At the last moment, the commander maneuvered the ship slightly away from the planned landing point to what he believed was a safer spot.

The Intrepid landed on Nov. 19, 1969, just a few dozen meters from the crater where Surveyor-3 had been sitting for the past two and a half years. The spot was around 1,300 miles west of Apollo-11's landing site.

Several hours after landing, Pete Conrad became the third person to step on the surface of the Moon. Perhaps embracing the falling interest of the general public toward the second lunar landing, Conrad began his moonwalk with humor instead of historic seriousness of his predecessor: "…Man, that may have been a small one for Neil, but that's a long one for me…"

During the first lunar walk, astronauts inspected the spacecraft, picked soil samples, deployed scientific instruments on the surface and wired them to a portable power generator using radioactive plutonium.

Only during the second outing did astronauts venture to the defunct Surveyor-3. Since they were expected to carry hardware from the probe back to their spacecraft, most other tasks of the excursion had to be completed first. Conrad and Bean spent most time on geology, but at one point they rolled a boulder into a crater to let scientists on Earth test the sensitivity of just installed seismic instruments.

At one point, astronauts lost view of their spacecraft and had to climb a nearby hill to get themselves oriented.

They eventually made it to the Surveyor, removed its TV camera and a soil-sampling scoop with some lunar regolith still inside, along with a few other minor fragments.

They finally returned to the Intrepid after walking for nearly eight hours.

While Conrad and Bean worked on the Moon, Gordon used a multispectral camera to photograph the lunar surface from orbit.

The two lunar walkers blasted off from the Moon after 31 and a half hours on its surface. They then successfully docked and transferred to the Yankee Clipper.

After the Intrepid was separated from the Yankee Clipper, the empty ascent stage was commanded to crash into the lunar surface, causing a major seismic event readily registered by newly installed sensors.

In the meantime, the Yankee Clipper remained in orbit of the Moon for an extra day to take photos of potential landing sites for future Apollo missions, including Fra Mauro, Descartes and Lalande craters.

The return trip was also uneventful, but at the splashdown on November 24, a camera inside the capsule fell and slightly injured Alan Bean.

The second expedition to the Moon lasted 10 days four hours 36 minutes.