 April 16, 1972, Apollo 16, man's fifth lunar landing, sat silently on the pad, awaiting its mission. Inside the astronaut quarters, its relaxed crew ate Sunday breakfast. John Young, a veteran of three previous space flights, was commanded. Ken Mattingly, command module pilot, would conduct orbital experiments around the moon, while Charles Duke explored the lunar surface with Young. April 22nd, Young and Duke would find themselves strapped into a small electric car called the rover, bouncing across the lunar plateau known as Descartes. Good day, Charlie. As Young and Duke rode the bucking rover to the lunar formation called Stone Mountain, NASA geologist Farouk L. Baz wrote on a blackboard on Earth, there is nothing so far removed from us to be beyond our reach or so hidden that we cannot discover it. Renee Descartes. As John Young would later remark, Apollo 16 would certainly help prove that Renee Descartes was right. Almost like a freshly plowed field that's been rained on. Yet less than two days before, it looked as though this would never happen. It was, in Young's words, a real cliffhanger. The Marshall Space Flight Center team was working on a launch vehicle gyroscope problem that threatened to scrub the mission. Less than an hour before liftoff, their advisory to the Kennedy Space Center launch team was go. The liftoff had been perfect. During the three-day flight to lunar orbit, the problems encountered had been more annoyances than critical, such as paint flaking off the lunar module and later a jammed antenna in one of the lunar modules several communication systems. All in all, it had been a quiet flight. April 19th, the burn into lunar orbit was right on. The subsequent maneuvers all went without a hitch. Then the next day, April 20th, Young and Duke undocked the lunar module preparatory to landing, leaving Mattingly in the command module. The next maneuver was for Mattingly to burn the main engine of his spacecraft to put it into a circular orbit. But as the lunar module emerged from behind the moon... No Cirque. No Cirque. In preparing for the circularization burn, Mattingly had found apparent uncontrolled oscillations in the main engine's backup control system. Following mission rules, he did not make the burn. How long do you think it's going to take him to get rid of it? I think you're estimate of a couple of three rounds. With the backup system having trouble, only the primary system was known to be usable on the engine needed to get the astronauts out of lunar orbit and back to Earth. However, the lunar module engines could be used if the two spacecraft were docked. The first step in the problem-solving technique stabilized the situation in the safest manner. Get the two spacecraft, which had separated, close enough together to dock, if necessary. Get them back together, get the things back as they want them to get them mentally prepared to do what they're going to do. But now, don't take that as input. I don't want to ask me to pitch something out loud. I don't want to say something out loud. I don't see any way we can continue on. At that moment, the chances for a landing looked pretty slim. But you look at a problem step by step. Step one underway, you look at step two. Analyze the problem as completely as possible within the time frame. We should make sure that that's covered. There's no way that there's no... You don't have any redundancy or other routes. And in lunar orbit, Mattingly flew the command module to Arandevu as Young talked him in. The work's coming back kind of initially from the North American if they're suspecting a great feedback. The team was coming up to speed, not only at the manned spacecraft center, but from MIT in Massachusetts to North American in Southern California. Isolate the trouble, simulate it, evaluate it. You can't use it if you've got a broken wire, you don't know it's going to come back again. Of course, then you would have had no options. I mean then it's full speed ahead. I just don't much see how we can make it on this next route. I think you guys ought to continue to work. So you'd only do it if you had a failure on the primary. Well, how would you ever get the damn thing trimmed then? I would. If I had a failure on the primary, I'd shut it down. Yeah, but I want you guys to simulate it. Isolate, simulate, evaluate. The results were coming in. It was beginning to pay off. The simulator tests and other data were showing that with the engine on, the oscillations would do no harm. Despite the earlier pessimism, it was beginning to look pretty good. Okay, when you come up on AOS on the next route, Route 15, we'll give you a go or no go for another try. Director Dr. Christopher C. Kraft, Jr. just came back into the control center after having a meeting by management people in one of the back rooms and the situation is go for landing. Well, have at it, babe, so we're going to try it. You do have a go for another try here at the PDI on Rev 16. Once more, they would pass behind the moon. And on the next revolution, John Young and Charlie Duke would start their swift descent to the Descartes Plateau. Okay, go to initialization. Looks good. See all that beauty? Come on. Looks like we're going to be able to make it. John, there's not too many blocks up there. Ryan, you go for landing. Right now it looks pretty good. Go ahead, go ahead. That comes a shadow. Okay, down at 3, 50 feet. Down at 4, give me one click up. The original plan had called for Young and Duke before shortly after landing. However, the nearer abort had lasted six hours. The tired astronauts would sleep. April 21, Mission Commander John Young stepped onto the Descartes Formation, 11.58 a.m. Eastern Standard Time. While their activities were monitored by mission control, Young and Duke were also observed by scientists, located across the hall in the science support room. After unloading the rover from its storage bay in the lunar module, they planted the flag. Young set up an ultraviolet camera to provide the first astronomical observations from the Moon. He took pictures of the Earth's upper atmosphere and magnetosphere and their interaction with the solar wind. He also photographed the interstellar gas present throughout space and the ultraviolet halos that appear around galaxies. Astronomers have long wanted a telescope on the Moon. Perhaps this experiment would show the Moon an ideal base for future astronomical observations. You want two pins? Yeah, we'd like two pins. I'm not laying it on the table. Duke drilled a hole into which a heat flow probe was to be placed, part of one of the experiments attached to the station. As Duke drilled, Young set up the central station and the remainder of the experiments. Then, what many considered the biggest disappointment of the mission. That means you've got to mate all those simple wires in there and have them insulated for one minute. And if that doesn't occur, what are the chances of shorting out the central station? That's another one that they're working on. On Earth, they tried to figure a way to fix the heat flow. On the Moon, the astronauts continued with the other experiments. Young placed a series of sensors in the soil, then fired explosive charges, mapping the lunar subsurface, much as geologists on Earth use explosives to search for oil. They continued to sample the area and activate the experiments. Then they returned to the rover and prepared for their first trip away from a landing site in search for geological samples. Their first traverse would take them about one kilometer west of the landing site. They would make two stops to collect samples and conduct experiments. Young used a portable instrument to measure the local magnetic field. He would later record the most intense magnetic field ever found on the Moon, far higher than scientists ever suspected. There would be one more stop before they got back to the lunar module to close out this EVA. With Duke acting as photographer and Young as driver, they put the rover through a full test. Then it was back to their lunar base, activate experiments, and close out EVA 1. On Earth, the scientists took a break. Tomorrow would be another busy day. April 22nd. The lunar surface temperature in the sun should be around 135 degrees today. Today they were headed a little over four kilometers south to climb their rover up the side of Stone Mountain. Their first station, which was at the bottom of the Moon, to climb their rover up the side of Stone Mountain. Their first station, a crater 700 feet above their lunar module. If we got that rake soil, if we got certainly something, we could go to one man sampling and maybe do it. They would make a total of six stops on this traverse, collecting samples from large rocks down through the intermediates to the smallest soil particles. They would operate experiments measuring the strength of local magnetic fields to measuring the resistance of the soil to compaction. The sampling time used up. It was time to return to the rover and head back to the lunar module. But with the limited oxygen and water in the backpacks, it was finally time to close out EVA-2. Now I think they realize that it's not more, well, a G-Weeze, like my friends say, thrill, but it's real exploration and this is much more serious and much more important for the future of mankind than just to plain exploit a technical or technological exploit. This is exploration. Ray Bradbury claims that what mankind sees in the exploration of space is his first chance at immortality since he's invented religion. April 23rd. The decision had been made not to try and fix the broken heat flow experiment because of the time and complexities involved. Traverse number three. Today, Young and Duke would head north about five kilometers to North Ray crater. The largest lunar crater to be sampled by men. Outstanding. Jack, that's a good point to remember. All three crews now tend to think they're there before they get there. I remember. These are the bottom of it and I'm as close to the edge as I'm going to get. Now the routine, if anything on the moon, can be called that. Test, collect, photograph. Keep moving. Time is precious on the moon. Then, one of the most spectacular discoveries of the mission. Look at the thing. It's not very clear. It was just right beyond you. Big black dots. Fantastic. Right here. I'm curious what they're going to look like when they stand next to each other. Through slowly. Keep going. Look for some variety. But now it was time to head back to their base and close out the EVA. We think you could just about head south now. During the previous EVA, a section of a rear fender had come off the rover, causing the astronauts to receive occasional showers of lunar dirt. Young parked the rover, then moved out to join Duke. Enter the lunar module and prepare for liftoff. Smile. FL. Don't be mad. We'll get it up there. See how nice and leisurely it's been? That's why it should be getting ready for us. Ten seconds. Together in orbit, the two spacecraft pirouetted, each inspecting the other. This is one of the fastest maneuvers I've made in a long time. The inspections complete. The command module and lunar module maneuvered to docking. John Young, Ken Matigley, and Charlie Duke reunited aboard the command module, settled down for tomorrow's tasks. Jettisoned the lunar module and burnout of orbit to come home. April 25. Ken Matigley left the confines of the command module cabin, 173,000 miles from Earth. As he orbited the moon, he had not only made visual observations, he had been operating a complex series of experiments. Many of these had returned instant data to Houston. Two had taken thousands of high-resolution pictures of the lunar terrain. Now, Matigley retrieved the film canisters and made his way back to the cabin with them. As Charlie Duke stood in the hatch to help him. It had been quite a mission. In John Young's words, April 27, the last day, the crew looked out their windows through the 5,000-degree fireball of re-entry at their native planet. That is beautiful, isn't it? It made this country great, and the kind of thing that's going to keep it that way. A real smooth shot. Every bit of it, Gary. Yeah, brought them in beautiful.