|Where No Man Has Gone Before: A History of Apollo Lunar Exploration Missions|
FIRST PHASE OF LUNAR EXPLORATION COMPLETED:
Intrepid Seeks Out Surveyor III
The morning of November 14, 1969, was cold, cloudy, and wet at Kennedy Space Center. Weather radar showed rain showers marking a cold front 80 miles (130 kilometers) north of the Cape and moving south. With launch only hours away, rain, broken low clouds, and overcast at 3,000 meters (9,800 feet) caused launch officials to consider their options. Reports indicated no thunderstorms or severe turbulence in the area, however, and conditions were better than the minimums specified by launch rules. An hour and 22 minutes before liftoff, a pump replenishing liquid oxygen in the launch vehicle tanks failed. With success depending on a backup pump, launch director Walter Kapryan chose to proceed.1 The crew had trained intensively for the specific features of the planned landing site, and if the day's launch window closed, that site would not be accessible for another month.
At 11:22 a.m. Eastern Standard Time, President Richard M. Nixon - the only incumbent chief executive ever to witness an Apollo launch - along with 3,000 invited guests and a large crowd of tourists, watched as the Saturn V rose from the pad and accelerated toward the clouds. Just before the vehicle disappeared into the overcast, two streaks of lightning flashed toward the launch complex. In the command module Yankee Clipper, mission commander Pete Conrad heard the master alarm. He looked at the caution and warning panel, and "it was a sight to behold." Sixteen seconds later another bolt discharged, and Conrad told Houston, "We just lost the platform [in the inertial guidance system], gang: I don't know what happened here; we had everything in the world drop out."2 The fuel cells had automatically disconnected and several panel gauges were temporarily disturbed, but otherwise everything seemed normal. After the crew reset the fuel cells, the flight continued while Mission Control tried to figure out what had happened and what the consequences might be. The best guess seemed to be that the launch vehicle, trailing its plume of ionized (and electrically conductive) exhaust gas, had triggered a lightning discharge that otherwise would not have occurred. Except for nine telemetry sensors not essential to the flight, all systems were normal.3
Apollo 12 flew smoothly into a normal earth orbit, and after the inertial guidance system was realigned and all systems checked out, Houston gave the signal to fire the S-IVB stage for translunar insertion. Three and a half hours into the flight, command pilot Richard F. Gordon turned command module Yankee Clipper around, extracted the lunar module Intrepid from its stowage site atop the third stage, and Apollo 12 continued on its way to the moon.4
The only midcourse correction maneuver of the outbound flight was performed the next day, a 9.2-second burn that put the spacecraft on a fuel - saving hybrid trajectory.5 For the rest of the uneventful three-and-a-half-day trip to lunar orbit, the crew spent their time housekeeping, tending to spacecraft systems, and observing the earth and the moon.6
Arriving at the moon 83 1/2 hours after liftoff, Conrad fired the main propulsion engine for almost 6 minutes to go into an elliptical lunar orbit. Five hours later a second burn put the spacecraft into a circular orbit at 60 nautical miles (111 kilometers) altitude, where Yankee Clipper would stay until it was time to return to earth. The spacecraft passed over and photographed Apollo 13's landing area in the Fra Mauro formation, and on the tenth revolution Conrad notified Capcom Gerald Carr that "you can tell good Captain Shaky [Jim Lovell, commander of Apollo 13] that he can relax. We've got his pictures."7
Six hours into the fourth day, Conrad and Bean prepared to enter and activate the lunar module. Both were having trouble with their biomedical sensors; Conrad's were blistering his skin and Bean's were producing erratic signals. Both men cleaned and reattached their electrodes, then finished donning their space suits and began preparing Intrepid for departure.8
For the next several hours Conrad and Bean in Intrepid and Gordon in Yankee Clipper were busy setting up their guidance and navigation computers and exchanging data with the ground. When all was ready, Gordon turned the spacecraft so that the long axis of the command and service module was perpendicular to the flight path with the lunar module outward from the moon, retracted the docking latches, and fired his attitude-control thrusters to move Yankee Clipper away from Intrepid.9 The landing craft was 5 miles (8 kilometers) north of its intended ground track - largely as a result of an error in the landing site location and the inability to adequately correct for the moon's irregular gravity field. This and other errors would be removed by the instructions transmitted to the guidance computer after the lunar module headed down for its landing.10
On the back side of the moon in the 13th revolution, the computer triggered a 29-second firing of the descent engine, bringing the low point of Intrepid's orbit to 8.1 nautical miles (15 kilometers). As the lander passed north of Mare Nectaris, Conrad turned it on its back with the descent engine pointed along the flight path and switched the engine on to begin the final approach. Everything went exactly as expected, and after two minutes Conrad commented that it "feels good to be standing up in a g-field again." Three minutes later the module's attitude-control thrusters began firing busily - more than Conrad thought they should - but Houston assured him that all was well.11
After seven minutes Intrepid nosed over into a near-upright position and for the first time Conrad could see the lunar surface. The principal landmark identifying his landing point was a pattern of craters the astronauts called "Snowman"; Surveyor III lay halfway up the eastern wall of the crater that was the Snowman's torso, and Intrepid was targeted for the center of the crater. As soon as he could see out the window, Conrad cried delightedly, "Hey, there it is [Snowman]! There it is! Son of a gun! Right down the middle of the road!" Then, as Bean called out altitude, velocity, and quantity of fuel remaining; Conrad maneuvered the craft with his hand controller to pick a smooth spot to land on. The engine exhaust began kicking up dust about a hundred feet (30 meters) above the surface and by the time Intrepid reached 50 feet ( 15 meters) the cloud obscured the surface completely. At 1:54:36 a.m. EST on November 20, Pete Conrad made a blind landing - exactly where, he could not tell, but certainly close to the intended spot.12
Conrad was naturally anxious to determine where he had set Intrepid down, and while he and Bean went through the post-landing check list they occasionally looked out the windows for landmarks that would allow Houston to pinpoint their location, but without success. After changing his mind a time or two, Conrad finally concluded, "I'm not sure that I'm not sitting fight smack on the other side of the Surveyor crater, just a little bit past it." Two hours later, Dick Gordon in Yankee Clipper confirmed Conrad's guess when he sighted both Intrepid and Surveyor III through his sextant as he passed over the site. He told Houston that the lunar module was "on the left shoulder of the Snowman. . . , about a third of the way from the Surveyor crater to the head.13 Postmission calculations placed Intrepid on the northwest rim of the Surveyor crater, 535 feet (163 meters) from the inert spacecraft.14 Had there been windows in the back of the lunar module, Conrad could have spotted the Surveyor as soon as the dust settled.
After postlanding checks of systems, Conrad and Bean described what they could see from their spacecraft. Intrepid had landed in undulating terrain pocked with craters ranging from a few feet to several hundred feet across, the larger ones rimmed by large blocks of rock. Numerous boulders, up to 20 feet (6 meters) in size, were scattered around the site, most of them angular rather than rounded, many showing fillets of dust around the base. Immediately in front of the landing craft Bean saw an area of "patterned ground" - parallel cracks in the surface soil perhaps an eighth of an inch (3 millimeters) deep. From the lunar module the crew could distinguish no color differences in the rocks or soil; everything seemed the same bright white.15 Five and a half hours after landing, Conrad squeezed out the hatch, then clambered down the ladder to the bottom rung. As he stepped off onto the landing pad Conrad remarked, "Man, that [step] may have been a small one for Neil, but that's a long one for me."* Looking around, he spotted the Surveyor halfway up the opposite wall of the crater. One of the first things Conrad noticed was that he was going to get extremely dirty: the surface dust was finer and deeper than he had expected.16
After Conrad had collected the contingency sample Bean joined him on the surface, bringing the television camera with him. A few minutes later Houston reported that the camera was not working. Cursory attempts at trouble-shooting were fruitless, and television coverage for the mission - desirable but not essential - had to be written off.** 17 The explorers pressed on with their other chores, apparently enjoying themselves immensely; Conrad chuckled and hummed to himself as he went about examining the lunar module, collecting and photographing samples, and describing the landscape.18
The primary objective of their first excursion was to deploy the scientific experiments. Conrad and Bean unloaded the package easily, picked a spot 130 meters (425 feet) northwest of the lander, and laid out the instruments without any serious difficulty.19 On their way back to Intrepid they picked up more documented samples and Bean took a soil sample with the core tube. After nearly four hours on the surface, the astronauts returned to the lunar module, dusted each other off as best they could without brush or vacuum cleaner, and climbed back inside. After a brief evaluation of the day's work and some discussion of the next day's plans, Houston signed off and the two astronauts strung up their hammocks and turned in.20
Overnight the geologists in Houston, working from several scenarios prepared before the mission, formulated detailed plans for the geology exercise the astronauts would carry out on their second outing. Next morning, when Bean and Conrad were awake and ready to talk, CapCom Paul Weitz read through the plans with them, discussing the scientists' recommendations for sampling and photography, while the astronauts offered comments based on the previous day's experience. Then they domed and checked over their space suits, recharged with oxygen their portable life-support systems, vented the cabin, and set out to collect samples.21
During the next four hours Bean and Conrad covered something more than one kilometer (3,300 feet), following a large-scale photographic map prepared for the traverse and chatting constantly with each other and with Houston.22 Scientists in Houston followed their progress from their references to the maps they carried. The extensive conversation was intended to substitute for a geologist's field notes.23 On the nearly featureless lunar surface, sampling proved somewhat difficult; except for size, most of the rocks showed few distinguishing features. Colors and textures were not always easy to determine, and when they were, the astronauts tended to use nonscientific terms in describing them - probably a symptom of their sensitivity to possible misuse of geological terminology. At one point Conrad noted a rock containing a "ginger-ale-bottle green" crystal (which was probably olivine), and a few minutes later Bean spotted a rock he said "looks almost like a granite," but immediately added, "of course it probably isn't, but it has the same sort of texture." Bean and Conrad documented their samples carefully, photographing many of them and describing the location and bag number for later reference. At "Head" crater, following instructions from Houston, Conrad dislodged a medium-sized rock and allowed it to roll down the slope to determine whether the seismometer some 70 meters (230 feet) away could detect it (it did). Then it was on to "Bench" and "Sharp" craters, where they sampled several large rocks on the surface that might be bedrock thrown out when the craters were formed.24
Two hours into the traverse the astronauts were on the edge of the Surveyor crater. The slope of the crater wall was much less than it had appeared the day before, when the low sun cast long, deceptive shadows. Pausing to reload a camera and survey the situation, they decided it would be easier to walk across the slope of the crater wall rather than come down from the rim. Approaching from the side, they could take photographs of the landing-pad imprints and the trenches dug by Surveyor's remotely controlled arm without disturbing the surface. These would be compared with television pictures transmitted from the spacecraft immediately after its landing.25
Examination of the Surveyor, the only human artifact ever encountered in lunar exploration, was among the more interesting parts of the mission for Conrad and Bean. What they noticed first was that much of its originally white surface had turned brown - a change they attributed to a deposit of dust when they found it could be wiped off. After photographing the surrounding surface and examining the spacecraft, they removed the Surveyor's television camera and cut off pieces of electrical cable and structural tubing for study by scientists at the Jet Propulsion Laboratory. They decided to remove the trenching scoop as well; then, after collecting soil samples, they headed for another small crater to take a few more samples on their way back to the lunar module.26
Back in their spacecraft, Conrad and Bean had almost six hours before lifting off to rendezvous with Yankee Clipper. After throwing out their portable life-support systems they straightened up the cabin, stowing the rock boxes and improvising stowage for the television camera, which Houston wanted to examine. They had carried in considerably more lunar dust than Armstrong and Aldrin had reported; Conrad told Houston they looked like "a couple of bituminous coal miners right at the moment, but we're happy."27
Despite the fact that they had trebled the existing record for lunar surface activity, Bean and Conrad were not exhausted and had expended about 10 percent less energy than anticipated. Both returned to the lunar module with almost 40 percent of their oxygen supply remaining on both excursions.28 Bean suggested to the medical officers that he would have enjoyed an occasional drink of water while working on the surface; not that he felt dehydrated, but he would have been more comfortable if he had been able to relieve the dryness in his mouth.29
Intrepid's ascent stage lifted off the moon on time, and an hour and a half later Conrad had Yankee Clipper in sight. Back in lunar orbit the dust the lunar explorers had brought in with them began to float, thick enough to be visible in the cabin. After the two spacecraft had docked they attempted to vacuum up the dust, with little success, so they removed and packaged their suits in the lunar module, hoping to minimize contamination of the command module. In spite of their efforts, considerable dust clung to everything they brought back and remained suspended in the atmosphere; the environmental control system seemed not to filter it out as completely as had been expected.30
Intrepid, now a useless hulk, still had one more contribution to make to the scientific objectives of the mission. For the benefit of seismologists wanting to calibrate the instrument that Bean and Conrad had just left on the moon, Mission Control now burned the empty spacecraft's remaining fuel to take it out of orbit. At a speed of 1.67 kilometers per second (3,735 miles per hour) the ascent stage plowed into the moon 76 kilometers (47 miles) east-southeast of the instrument package, producing a bizarre response: the seismometer recorded vibrations that persisted almost undiminished for nearly an hour. It was so completely unlike anything ever seen on earth that seismologists had no immediate explanation. One scientist compared the result to striking a church bell and hearing the reverberations for 30 minutes.31
Yankee Clipper stayed in lunar orbit for 11 more revolutions, finishing up the "bootstrap" photography and landmark tracking, looking at sites being considered for Apollo 14 and 15. Then the crew boosted their spacecraft out of lunar orbit and settled in for the three-day voyage home. Now and then they chatted with the duty CapCom about something that crossed their minds concerning their exploration. Once in a while scientists wanted to debrief them concerning details of their lunar surface activity. For most of the time, however, they relaxed.32
At one point both Conrad and Bean passed along some reservations they
had about the field geology exercise. They had found the lunar surface a
particularly difficult one for classical field-geological techniques.
Early on the morning of November 24 Apollo 12 splashed down some 600 kilometers (375 miles) east of Pago Pago, 3.5 kilometers (2 miles) from the recovery ship U.S.S. Hornet. The landing was rough - apparently Yankee Clipper hit a rising wave as it swung on its parachutes - hard enough to dislodge a 16-mm movie camera from its bracket and slant it into Alan Bean's forehead, momentarily stunning him and opening a 1-inch (2.5-centimeter) cut, which Conrad bandaged.36
The recovery swimmers soon arrived, tossed respirators and coveralls - replacing the biological isolation garments that the Apollo 11 crew had found so objectionable - into the command module, then assisted the astronauts into the raft. Half an how later recovery helicopters set the crew down aboard the Hornet and they went straight to their mobile quarantine facility. Lunar sample containers and film magazines were removed and flown to Pago Pago and thence to Houston. The astronauts had a longer journey: four days aboard ship to Hawaii, then a nine-hour flight to Houston. On the morning of November 29, Conrad, Bean, and Gordon entered the Lunar Receiving Laboratory for their 11-day stay in quarantine.37
That Apollo 12 was a success was apparent even on preliminary evaluation. The procedural changes incorporated to improve landing accuracy had allowed Conrad to put Intrepid down within sight of Surveyor III, exactly as intended. Lunar exploration had been easy; neither Bean nor Conrad encountered any unexpected difficulties and both had oxygen to spare when they returned. And while they had found it hard to apply their field - geology training on the unrevealing surface of Oceanus Procellarum, they had collected nearly 75 pounds (34 kilograms) of samples, most of them documented. The surface experiments they had set up were returning streams of data, and scientists agreed the astronauts had done a remarkable job. Communication between scientists in Houston and the astronauts on the moon had been well handled by Mission Control.38 If Apollo 12 was a reliable indicator, the scientific return from the remaining eight missions should be gratifying.
* At 5 feet 6 inches (168 centimeters), Conrad was one of the shorter astronauts; Armstrong was just under 6 feet (183 centimeters). The lowest rung of the ladder was about 2.5 feet (75 centimeters) above the landing pad.
** Later examination determined that the image-tube target in the camera had been damaged by exposure to intense light. Apparently Bean had inadvertently pointed the camera at the sun or a reflection off the lunar module while helping Conrad set up a directional antenna. MSC-01855, "Apollo 12 Mission Report," March 1970, p. 14-50,
1. Charles D. Benson and William Barnaby Faherty, Moonport: A History of Apollo Launch Facilities and Operations, NASA SP-4204 (Washington, 1978), pp. 481-82.
3. MSC, "Apollo 12 Technical Air-to-Ground Voice Transcription," prepared for Data Logistics Office, Test Div., Apollo Spacecraft Program Office, Nov. 1969 (cited hereinafter as "12 Air-to-Ground"), p. 17; MSC, "Apollo 12 Mission Report," MSC-01855, March 1970, pp. 14-2 to 14-4.
Postflight analysis of available data supported the first tentative conclusion. Electric-field measurements at the launch site indicated that the clouds were charged, but not enough to produce lightning. The passage of a conductor (such as the launch vehicle) is known to produce lightning under such conditions. Witnesses disagreed on the question of lightning strikes, but photographs showed two bolts from cloud to ground 36.5 seconds after launch, neither of which produced damage. The second discharge, 52 seconds after launch, was probably between clouds. See MSC-01540, "Analysis of Apollo 12 Lightning Incident," Feb. 1970. Damage to the launch vehicle was negligible (several telemetry sensors on the service module were knocked out), but launch rules were subsequently tightened to forbid launch under weather conditions favorable to lightning strikes.
4. 12 Air-to-Ground, p. 24.
5. Apollo 12 Mission Report, p. 5-4.
6. Ibid., p. 5-5.
7. 12 Air-to-Ground, p. 292.
8. Ibid., pp. 281-92.
9. Ibid., pp. 292-322.
10. Apollo 12 Mission Report, pp. 5-7 to 5-8.
11. 12 Air-to-Ground, pp. 335-45; Apollo 12 Mission Report, p. 5-9.
12. 12 Air-to-Ground, pp. 346-68; Apollo 12 Mission Report, p. 6-3.
13. 12 Air-to-Ground, pp. 348-68.
14. Apollo 12 Mission Report, pp. 4-25 to 4-27.
15. 12 Air-to-Ground, pp. 370-73.
16. Ibid., pp. 406-ll.
17. Ibid., pp. 418-26; Apollo 12 Mission Report, p. 14-50.
18. 12 Air-to-Ground, pp. 429-60.
19. Apollo 12 Mission Report, p. 3-26; 12 Air-to-Ground, pp. 438-73.
20. 12 Air-to-Ground, pp. 473-521. Neil Armstrong and Buzz Aldrin had difficulty finding a way to sleep comfortably in the cramped LM. Hammocks were added on Apollo 12 and Bean and Conrad found them quite comfortable in lunar gravity.
21. 12 Air-to-Ground, pp. 553-89.
22. Ibid., pp. 597-716.
23. The Lunar and Planetary Missions Board recommended in early 1968 that astronauts should talk as much as possible ("almost incessant talking," as the Board put it) while on the lunar surface, describing what they were doing, what they could see and how they interpreted it, and what they intended to do next and why, to provide a complete record of their surface activity, Homer E. Newell to Robert R. Gilruth, Feb. 5, 1968. MSC agreed in principle only, suggesting that the astronauts observe the tried and proven rules of aircraft communications, transmitting only necessary information while at the same time making an effort to provide "a running commentary of significant events and actions so preplanned that normal communications discipline is not violated but yet is complete enough to assure a maximum of scientific return from the exercise." That kind of commentary would be "comparable to the usual field notes of the practicing geologist on a field trip." Gilruth to Newell, Feb. 20, 1968; W. N. Hess to Special Asst. to the Dir., "Astronaut Activity on Lunar Surface," Feb. 19, 1968.
24. 12 Air-to-Ground, pp. 602, 603, 614-52. After Buzz Aldrin drew criticism from scientists for his misidentification of biotite (see footnote, chap. 9, p. 282), Bean and Conrad may have been more sensitive to what they were saying. Geologist-astronaut Jack Schmitt noted that in postmission discussions Conrad admitted he was fairly sure the sample was olivine, but "he wasn't about to say so," for fear of making a mistake. H. H. Schmitt interview, May 30, 1984.
25. 12 Air-to-Ground, pp. 661, 666, 670.
26. Ibid., pp. 671-95.
27. Ibid., p. 731.
28. Apollo 12 Mission Report, pp. 10-7, 8-20.
29. Ibid., p. 9-10; 12 Air-to-Ground, p. 740.
30. 12 Air-to-Ground, pp. 757-770; MSC, "Apollo 12 Technical Crew Debriefing," Dec. 1, 1969, pp. 12-21 to 12-23; Apollo 12 Mission Report, pp. 6-5 to 6-6.
31. Apollo 12 Mission Report, pp. 3-10 to 3-11, 9-39 to 9-40; Victor Cohn, "Moon Quake Caused by Lem Called 'Unlike Any' on Earth," Washington Post, Nov. 21, 1969; Gary V . Latham, Maurice Ewing, Frank Press, George Sutton, James Dorman, Hosio Nakamura, Nafi Toksoz, Ralph Wiggins, and Robert Kovach, "Passive Seismic Experiment," in Apollo 12 Preliminary Science Report, NASA SP-235 (Washington, 1970) , pp. 39-53.
32. 12 Air-to-Ground, pp. 863-1066, 944-57; Apollo 12 Mission Report, p. 9-28.
33. 12 Air-to-Ground, pp. 924-25.
34. Alan L. Bean interview, Apr. 10, 1984.
35. 12 Air-to-Ground, p. 1018.
36. Apollo 12 Technical Crew Debriefing, pp.16-1, 16-4.
37. Apollo 12 Mission Report, pp. 11-6 to 11-7.
38. Cohn, "Moon Quake Caused by Lem."