Apollo 12 Mission Marks Second Moon Landing Summary

  • Last updated on November 10, 2022

The second piloted lunar landing was achieved with pinpoint accuracy and paved the way for future scientific exploration of the Moon. The astronauts completed two separate moonwalks, set up an automated scientific analysis package, and recovered equipment from the Surveyor 3 probe.

Summary of Event

Four months after the triumph of Apollo 11, the mission planners at the National Aeronautics and Space Administration National Aeronautics and Space Administration;Apollo program (NASA) were about to show that an astronaut crew not only could repeat the lunar landing mission but also could do so with controlled precision. The flight to the Ocean of Storms would begin in a storm on Earth. Apollo space program Space program, U.S.;Apollo program Lunar exploration Astronauts and cosmonauts [kw]Apollo 12 Mission Marks Second Moon Landing (Nov. 19-20, 1969) [kw]Moon Landing, Apollo 12 Mission Marks Second (Nov. 19-20, 1969) [kw]Landing, Apollo 12 Mission Marks Second Moon (Nov. 19-20, 1969) Apollo space program Space program, U.S.;Apollo program Lunar exploration Astronauts and cosmonauts [g]North America;Nov. 19-20, 1969: Apollo 12 Mission Marks Second Moon Landing[10540] [g]United States;Nov. 19-20, 1969: Apollo 12 Mission Marks Second Moon Landing[10540] [c]Space and aviation;Nov. 19-20, 1969: Apollo 12 Mission Marks Second Moon Landing[10540] [c]Science and technology;Nov. 19-20, 1969: Apollo 12 Mission Marks Second Moon Landing[10540] Conrad, Pete Gordon, Richard F. Bean, Alan L.

The successful completion of the Apollo 11 mission was a relief to all who had worked so hard to accomplish the task. It was even more so for the Apollo 12 team, who had its launch pushed back to November, giving crew members two additional months to prepare. Some of that preparation time would be extremely useful, since the mission planners had selected the Surveyor 3 site as their target.

Surveyor 3 landed on April 20, 1967, and transmitted 6,326 photographs and large amounts of scientific data for two weeks. Even though the scientists on the Apollo Site Selection Committee had rejected unanimously its location as unsuitable, Surveyor offered a unique opportunity. Future lunar landings needed to be made at specific locations, and a landing by Apollo 12’s Lunar Module (LM) within 1 kilometer (six-tenths of a mile) of a target would demonstrate this capability. In addition, by retrieving certain removable components from Surveyor, the effects of their exposure to two years on the Moon’s surface could be studied. Apollo 12 would set up the first operational Apollo Lunar Surface Experiments Package (ALSEP), make extensive geological observations and sample collection, and conduct photographic observations from lunar orbit.

Launch day—November 14, 1969—dawned gray, cold, and wet. Weather radar showed rain showers 130 kilometers (80 miles) north of the Cape Kennedy, Florida, launch complex and heading south. Forecasters, however, believed that the area would be dry at the scheduled lift-off time. One hour and twenty-two minutes before launch, a pump replenishing liquid oxygen in the Saturn 5 launch vehicle’s tanks failed. Contrary to the strictest launch rules, the decision was made to fly with only the backup pump operating. The astronaut crew had trained extensively for the specific conditions at the planned landing site and if the day’s launch window was missed, it would be another month before it reopened.

At seven-tenths of a second past 11:22 a.m., eastern standard time, Apollo 12 lifted off into the thick overcast. Just before the vehicle disappeared, two streaks of lightning flashed toward Launch Complex 39. At the same time, Mission Commander Pete Conrad in the Command Module Yankee Clipper Yankee Clipper (spacecraft) radioed that they had momentarily lost the inertial guidance system. Apparently, as the vehicle passed through the electrically charged clouds, the lightning discharged down the ionized (and therefore, electrically conductive) exhaust plume. This overloaded the fuel cells, which provide power to the spacecraft, and caused them to shut down automatically. The crew reset the circuit breakers and the flight continued normally.

Once safely in Earth’s orbit, the crew began the task of ensuring that all systems were operating properly. The inertial guidance platform was realigned and the Saturn’s third stage placed the spacecraft on its way to the Moon. Several minutes later, Yankee Clipper extracted the Lunar Module Intrepid Intrepid (spacecraft) from the stage and the two proceeded to their destination. A single midcourse maneuver was performed to place the craft on a fuel-saving hybrid trajectory, one which would not bring them automatically back to Earth.

The journey to the Moon was uneventful, as was lunar orbit insertion. While in orbit, the astronauts performed photographic tasks, including taking pictures of Apollo 13’s target landing site in the Fra Mauro region. On the fourth day, Conrad and Bean powered up the LM and began their descent to the Ocean of Storms.

At 1:54:36 a.m. on November 20, Conrad set Intrepid down on the surface. As the dust settled, Conrad and Alan L. Bean began to describe the landing site, but they could not see Surveyor. Had there been windows in the back of the LM, they would have spotted the dormant spacecraft a mere 163 meters (535 feet) behind them.

Five and a half hours after landing, Conrad made his way out of Intrepid’s front hatch and down the ladder to the surface. On his way down, he pulled a lanyard, releasing the door on a storage bay in the lower half of the LM. A color television camera in the bay transmitted his descent to the surface. “Man, that ’step’ may have been a small one for Neil, but that’s a long one for me,” Conrad exclaimed as he stepped from the lowest rung of the ladder to the foot pad. Conrad, one of the shorter astronauts, was 15 centimeters (6 inches) shorter than Armstrong. The lowest ladder rung was about 75 centimeters (30 inches) above the foot pad. As he looked around, Conrad spotted the Surveyor spacecraft behind the LM.

Alan L. Bean descends from the Lunar Module Intrepid during the Apollo 12 mission on November 19, 1969.

(NASA Charles Pete Conrad)

In the event an emergency lift-off from the Moon became necessary, a small contingency sample was collected by Conrad while Bean prepared his descent to the surface. Soon, they were both on the Moon, preparing to deploy the ALSEP.

The two spent nearly four hours on the lunar surface during the first walk, collecting 16.7 kilograms (37 pounds) of soil and rock samples, taking photographs, and setting up their experiments’ package. The next day, armed with new plans formulated by geologists in Houston for collecting samples, the pair began their second EVA. During the next four hours, they covered a little more than 1 kilometer (two-thirds of a mile) and collected 17.6 kilograms (39 pounds) of samples. Halfway through the second EVA, the astronauts approached the Surveyor III spacecraft and began photographing it in its untouched state. Later, television pictures taken of the same area by Surveyor’s camera immediately after it had landed could be compared with the photographs.

With near reverence for the only human artifact ever encountered on the Moon, Conrad and Bean examined Surveyor and noted that much of its originally white surface had turned brown. They attributed the change to a layer of dust on the exposed surfaces that was easily brushed away to reveal the original white paint beneath. They removed Surveyor’s television camera and cut off electrical cabling and structural tubing for study by scientists in Houston. Then they removed the trenching scoop, collected a few more samples, and headed back toward the LM.

At the close of the second moonwalk, Conrad and Bean climbed back into Intrepid and prepared for the journey home. They were covered in a layer of moon dust and despite their efforts to brush it off, it stuck with them. Before rejoining Richard F. Gordon in Yankee Clipper, they attempted to vacuum the dust, with little success. They brought a considerable amount with them into the Command Module and it remained in the spacecraft until they returned to Earth.

After undocking Intrepid and sending it to crash into the Moon to help calibrate the Passive Seismometer they had left at the landing site, the crew fired Yankee Clipper’s engine to bring them back home. Early on the morning of November 24, Apollo 12 splashed down some 600 kilometers (375 miles) east of Pago Pago.

Significance

The flight of Apollo 12 is overshadowed generally by its predecessor Apollo 11 and by its successor Apollo 13. Apollo 11 fulfilled the goal set by President John F. Kennedy to land a human on the Moon by the end of the decade and return that person safely to Earth. From the beginning, Apollo 12 was planned as a backup to Apollo 11. If something were to go wrong, the Apollo 12 crew still would achieve the original goal by the deadline. Once Apollo 11 was successfully completed, the crew had to shift its attention to an even more difficult goal, that of an accurate landing on the Moon. They were to land within one kilometer of a targeted site. This was equivalent to firing a rifle to hit a dime on a moving train 32 kilometers (20 miles) away.

Subsequent lunar missions would use the knowledge gained by Apollo 12 both in the targeting of landings and in the science that would be accomplished. None would require the accuracy of Apollo 12’s landing feat, but the techniques used by ground controllers and by the astronauts would permit future crews to look for the most desirable site for their exploration. Geologists in Houston had always pushed for the inclusion of a geologist in a lunar landing crew. They believed that a geologist was best suited for finding the most significant samples to bring back to Earth. They also believed that a geologist could best describe the location of the sample before it was retrieved, thereby making it easier to understand the geological processes it took to place the sample where it had been.

Conrad and his fellow test-pilot astronauts argued that it took all of the piloting skills he had to accomplish the landing and that pilots could be trained to be relatively good field geologists. In addition, they argued that even a trained field geologist would have trouble doing much field geology on the Moon. With its smaller diameter, and therefore closer horizon, in combination with the unusual lighting conditions, the visual clues used on Earth did not work on the surface of the Moon. Once the pilots had a handle on landing techniques, a geologist could be brought along as the Lunar Module Pilot, since the Commander actually lands the LM. The geologists would have to wait for Apollo 17 through 20 to practice their trade up close. Nevertheless, public interest in lunar landings waned after Apollo 13 and congressional cutbacks forced NASA to cancel the last three planned missions. A geologist, Harrison Schmitt, did make it to the Moon. He was Lunar Module Pilot on the Apollo 17 mission, the last flight of Apollo.

In the meantime, the seven pilot-astronauts who explored the lunar surface after Apollo 12 proved that they were capable of being trained to find important geological examples. The morphology and stratigraphy of the vicinity could be understood to the point that they would know where to find these samples. They spent more time collecting and documenting the samples than doing on-the-spot geology. In doing so, they were able to bring back numerous examples for the geologists to study.

The crew of Apollo 12 could not claim to be the first or the last to explore the Moon. They did not walk the farthest nor drive a lunar dune buggy. They did not spend the most time on the surface nor did they bring back the most rocks. They do, however, still hold the record for landing the closest to their target. Apollo space program Space program, U.S.;Apollo program Lunar exploration Astronauts and cosmonauts

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bilstein, Roger E. Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. NASA SP-4206. Washington, D.C.: Government Printing Office, 1980. This book chronicles the Apollo program literally from the ground up. Details of each Saturn flight are presented in chronological order. Fully illustrated and sporting an impressive forty-page bibliography, the book provides details on Apollo available nowhere else.
  • citation-type="booksimple"

    xlink:type="simple">Brooks, Courtney G., James M. Grimwood, and Loyd S. Swenson, Jr. Chariots for Apollo: A History of Manned Lunar Spacecraft. NASA SP-4205. Washington, D.C.: Scientific and Technical Information Branch, 1979. The “official” record of America’s voyage to the Moon. Contains many black-and-white photographs of the flights leading to the Apollo 11 mission. Detailed source notes and an extensively annotated bibliography provide much information for the researcher.
  • citation-type="booksimple"

    xlink:type="simple">Compton, William David. Where No Man Has Gone Before: A History of Apollo Lunar Exploration Missions. NASA SP-4214. Washington, D.C.: Government Printing Office, 1989. The story of the astronauts chosen to participate in the lunar missions introduces the people behind the scenes. Contains many black-and-white photographs and drawings and a completely annotated source listing, which is almost as valuable as the manuscript.
  • citation-type="booksimple"

    xlink:type="simple">Godwin, Robert, ed. Apollo 12: The NASA Mission Reports. 2 vols. Burlington, Ont.: Apogee Books, 1999. This volume is an invaluable resource on the Apollo 12 mission. Includes never-before-published material from the NASA archives, many photographs and illustrations, a CD-ROM, and maps.
  • citation-type="booksimple"

    xlink:type="simple">MacKinnon, Douglas, and Joseph Baldanza. Footprints: The Twelve Men Who Walked on the Moon Reflect on Their Flights, Their Lives, and the Future. Washington, D.C.: Acropolis Books, 1989. One of the best books on the Apollo 11 mission. The authors interviewed the twelve men who had walked on the Moon. Each interview revealed more about the inner feelings of the astronauts than any prior publication.
  • citation-type="booksimple"

    xlink:type="simple">Murray, Charles, and Catherine Bly Cox. Apollo: The Race to the Moon. Burkittsville, Md.: South Mountain Books, 2004. An intriguing look at the people who worked on the Apollo program. Reference notes, black-and-white photographs.
  • citation-type="booksimple"

    xlink:type="simple">National Aeronautics and Space Administration. Analysis of Surveyor 3: Material and Photographs Returned by Apollo 12. Washington, D.C.: National Technical Information Service, 1972. Discusses what exposure to the lunar “atmosphere” does to human-made equipment. This information was useful in designing equipment for replacement on the lunar surface by future crews. Includes black-and-white photographs taken by astronauts Conrad and Bean.
  • citation-type="booksimple"

    xlink:type="simple">National Aeronautics and Space Administration. Apollo Mission Press Kits. http://www-lib.ksc.nasa.gov/lib/presskits.html. Official preflight information about Apollo 6 through Apollo 17.
  • citation-type="booksimple"

    xlink:type="simple">U.S. Manned Spacecraft Center, Houston, Texas. Apollo 12 Preliminary Science Report. NASA SP-235. Springfield, Va.: Scientific and Technical Information, 1970. Topics covered include landing site selection criteria; mission description; and a summary of scientific, photographic, and geologic results. Contains many photographs, line drawings, and data tables. Each section has its own comprehensive reference list. Provides many facts and figures for the researcher.

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