Apollo 12 astronaut Pete Conrad and fellow astronaut Alan Bean stepped out of the lunar module onto the Moon’s surface on November 19, 1969. This historic mission happened just four months after Neil Armstrong and Buzz Aldrin made their first lunar landing. Pete Conrad was the third man to set foot on the lunar surface, and Alan Bean was the fourth person to walk on the Moon.
Conrad and his fellow astronauts Bean and Richard Gordon had all met as pilots in the Navy. And they were all old friends; they all knew each other before they became Apollo astronauts. If Apollo 11 mission was about proving it was possible to land on the lunar surface, Apollo 12 was about doing it better. The primary focus of Apollo 12 was the pinpoint landing. And Charles “Pete” Conrad Jr. was considered one of the best pilots of the Apollo astronauts.
Apollo 12 Crew
- Charles “Pete” Conrad Jr., Commander
- Alan L. Bean, Lunar Module Pilot
- Richard F. Gordon Jr., Command Module Pilot
Apollo 12 Backup Crew
- David R. Scott, Commander
- James B. Irwin, Lunar Module Pilot
- Alfred M. Worden, Command Module Pilot
What Was The Apollo 12 Mission?
The second crewed lunar landing’s primary mission objectives included an extensive series of lunar exploration tasks. For example, it involved deploying the Apollo Lunar Surface Experiments Package, or ALSEP, which was to be left on the lunar’s surface to gather scientific, seismic, and engineering data during an extended period.
Other Apollo 12 objectives involved a selenological inspection; development of techniques for precision-landing capabilities; surveys and samplings in landing areas; further evaluations of the human capacity to work in the lunar environment for a prolonged time; deployment and retrieval of other scientific operations; and photography of candidate exploration sites for coming moon missions.
Was Apollo 12 Planned For a Daylight Launch?
The astronauts should also recover portions of the Surveyor III spacecraft. It had soft-landed on the Moon April 20, 1967, a short distance from the chosen landing site of Apollo 12. This was the first non-free-return trajectory on an Apollo mission to allow a daylight launch and a translunar injection over the Pacific Ocean. It allowed a stretch of the translunar coast to gain the desired landing site lighting at the time of Lunar Module descent. It also conserved fuel and let the Goldstone, Calif., tracking antenna to monitor the Lunar Module’s descent and landing.
What Was the Apollo 12 Flight Plan?
The Apollo 12 mission’s flight plan called for the Lunar Module ascent stage to provide a measured seismic stimulus for the Apollo Lunar Surface Experiments Package, or ALSEP, seismic experiment.
Following crew return to the CSM or the command and service module, a controlled burn of the remaining fuels in the empty ascent stage caused the stage to crash into the lunar surface, providing a measurable seismic shock impulse.
Apollo 12 Lightning
Apollo 12 got off to an ominous start. The Saturn V rocket launched from Cape Kennedy on Nov. 14, 1969, into a cloudy, rain-swept sky. There were thunderstorms on the day of the launch, and their Saturn V rocket was struck by lightning twice as it climbed skyward.
The launch controllers lost telemetry contact at 36 seconds and again at 52 seconds when the Saturn V rocket was struck by lightning. It had led to an electrical problem that shut down a lot of the controls. Luckily the Saturn V rocket kept flying, and with the help of Mission Control, the crew was able to recover power to all of their systems. After one-and-a-half revolutions, the electrical circuits were checked out, and no notable problems were seen.
Nevertheless, based on incorrect data of trajectory commands, it failed to go into the planned heliocentric orbit. Instead, it was placed into an elliptical Earth-orbit of 101,350 by 535,522 miles, with a period of 42 days.
What Was Apollo 12’s Trajectory?
But only one midcourse maneuver was required. It changed Apollo 12’s trajectory to later insertion into a non-free-return lunar orbit – the first “hybrid” trajectory in Apollo flights. The spacecraft slowed to arrive with the most desirable solar illumination on the selected Site 7. On Nov. 19, with the Lunar Module now behind the moon in its 14th orbit and 109 hours, 23 minutes into the flight, the descent orbit insertion maneuver started.
The Lunar Module’s descent engine, or LMDE, fired for 29 seconds, lowering Intrepid’s orbit to about nine by 69 miles. After the Lunar Module appeared from behind the moon and telemetry contact was re-established with Earth, a discrepancy was seen between orbit data readings from Intrepid and those displayed in Apollo Mission Control in Houston.
Credit: Wikipedia/NASA.
Wrong Descent Orbit Trajectory?
Due to typical mission anomalies, the Lunar Module was initially believed to be in a wrong descent orbit trajectory for touching down in the desired region. But by using a newly improved “Lear” powered-flight data processor in Houston, the actual trajectory data and correction maneuver information were supplied by voice to the Lunar Module crew.
Furthermore, this enabled them to update the automatic downrange navigation computer program, reducing the range by 4,190 feet and allowing the precision touchdown at the intended site.
This update to a satisfactory trajectory happened about two minutes after the Lunar Module entered its powered descent, which had been started at about 110 hours, 20 minutes into the mission, and remained a mere nominal 40 seconds longer than the preflight plan had scheduled.
Apollo 12 Landing Site
With Pete controlling the descent semi-manually for the last 500 feet, a precision landing happened at around 110 hours, 32 minutes into the mission, and closer to the target than expected. Intrepid touched down in the Ocean of Storms at 3 degrees, 11 hours, 51 minutes south, 23 degrees, 23 minutes, and 7.5 seconds west.
The landing was about 120 feet northeast of Head Crater and approximately 535 feet northwest from where Surveyor III stood in its crater. Apollo 12 landed around 950 miles west of where Apollo 11 had landed.
Pete spent three hours, 39 minutes outside Intrepid, and Bean logged two hours, 58 minutes. During this EVA, Conrad accumulated lunar surface samples and deployed both the S-band communication antenna and the solar wind experiment. Alan Bean was assigned to mount the TV camera on a tripod. In doing so, it was accidentally pointed into the sun, and it stopped function.
Apollo 12 Experiments
The Apollo Lunar Surface Experiments Package instrumentation and SNAP-27 RTG were deployed within an arc of 600 to 700 feet of the Lunar Module. The Apollo Lunar Surface Experiments Package performed satisfactorily, except for two items in the package, and was expected to yield data for up to two years.
And before entering the Intrepid, Alan took a 16-inch-deep core sample of the Moon’s surface and was followed back into the Lunar Module by Pete.
On Nov. 20, an hour and a half earlier than intended, the crew began the second EVA. The most important part of this second extravehicular activity was a 5,200-foot traverse of the lurain, ranging up to 1,300 feet from Intrepid.
Throughout the exploration, the astronauts discussed their findings by voice communication with geologists in Houston, who gave advice about which samples to retrieve. Their second EVA lasted three hours, 48 minutes.
How Long Time Did Apollo 12 LM Ascent Stage Fire?
On the same day, approximately six hours later, after a total of 31.6 hours on the Moon, the LM ascent stage fired for around seven minutes, putting Intrepid into the first orbit for rendezvous and docking with the Yankee Clipper. Gordon’s rendezvous and docking maneuvers were televised back to Earth about three and a half hours later.
Following transfer to the Apollo command and service module, the ascent stage jettisoned and deorbited to impact the lunar surface. This provided predictable impact data for the ALSEP seismometer. But to the surprise of seismologists, the strong signals lasted for more than a half-hour, and weaker signals ceased around an hour later.
A heavy program of photographing future landing sites on the lunar surface occurred from the Apollo command and service module. Earlier, when the Yankee Clipper was in its 27th and 28th revolutions, Richard Gordon conducted the lunar surface’s multi-spectral photographic survey.
Credit: NASA/Wikipedia.
When Did Apollo 12 Return?
And during the 45th revolution, the SPS ignited to put Apollo 12 into a trans-Earth trajectory on Nov. 21. The return flight was uneventful. On November 24, 1969, at 3:58:24 p.m. EST, following the identical nominal re-entry procedure scheduled for Apollo 11, Apollo 12 completed its ten-day flight by splashing down in the Pacific Ocean. The splashdown happened about three miles from the target area and three miles south of and within sight of USS Hornet’s recovery ship.
The splashdown occurred approximately 400 miles southeast of American Samoa and after a flight of 244 hours, 36 minutes, 25 seconds. It was just 62 seconds longer than planned.
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