Apollo 16: An Adventure of Breccias and Bowel Movements

Captured from aboard Orion on the afternoon of 20 April 1972, this view shows Earthrise and - just to the left of the Home Planet - the command and service module, Casper, piloted by Ken Mattingly. Photo Credit: NASA

Forty years ago, tonight, a trio of astronauts floated literally in limbo, high above the Moon. Aboard the spider-like lunar module Orion, Apollo 16 crewmen John Young and Charlie Duke were ready to begin three days of exploration in the lunar highlands and anticipated a landing in the mountainous Cayley region, 50 km south of the crater Descartes. One major obstacle, though, stood in their way. A problem had been discovered with the large engine on their command and service module, Casper, which was being piloted by crewmate Ken Mattingly. After much deliberation, at 7:00 pm EST, the relieved astronauts were advised that the Moon landing was back on. Two and a half hours later, Young and Duke guided their craft down over the mountains and touched down on an undulating plain, midway between a pair of bright-rayed craters, nicknamed ‘North Ray’ and ‘South Ray’. Geologists were virtually convinced that the site was volcanic in origin and would produce rock and soil samples to support this hypothesis The seriousness and importance of this mission received a little light relief through the endearing Carolina drawl of Charlie Duke. He was on the Moon…a place only eight other humans had ever walked, and his excitement was pervasive. “Wowwwww,” he exulted, like a child at a fair. “Whoa, man. Old Orion is finally here, Houston. Fan-tas-tic!”

With four previous lunar landings under its belt, NASA had become – in Deke Slayton’s words – somewhat blasé about operating in this most hostile of environments. Original plans called for Young and Duke to make the first of their three Moonwalks immediately, but the six-hour delay in landing prompted Mission Control to recommend that they sleep first. This would have unavoidable ramifications on the timeline and checklists, but it was clear that a strenuous EVA, directly after landing, would have meant a 27-hour day. Not surprisingly, the astronauts were game, but Flight Director Gerry Griffin would have none of it. “We agreed,” Charlie Duke told the Apollo Lunar Surface Journal, “but it turned out I wish we hadn’t. I wish we had gone on out and stuck to our timeline, because it required a lot of changes in the procedures once we landed.”

By now, the lunar modules had been expanded in terms of capability. The early landings could remain on the Moon for a maximum of 33 hours and support two Moonwalks, but from Apollo 15 onwards a newer specification ‘J-series’ craft provided for three-day stays on the surface and three lengthy EVAs of perhaps six or seven hours apiece. Inside Orion, Young and Duke removed their space suits – which ‘stood’ in the weak lunar gravity, at the back of the cabin – and settled into their hammocks to sleep. Young fell asleep directly, but Duke’s mind was racing. He took a sleeping pill and finally dozed off.

Backdropped by Stone Mountain at left, the lunar module Orion rests on the Moon during Apollo 16. John Young and the rover can be seen in the background on the right of this image. Photo Credit: NASA

Fourteen hours later, at 11:59 am EST on 21 April 1972, Young hopped down Orion’s ladder and became the ninth human to plant his boots into lunar dust. “There you are, our mysterious and unknown Descartes highland plains,” he breathed. “Apollo 16 is gonna change your image!”

There was some doubt, even at this stage, that the mission might run as intended. In view of the late landing, managers were considering whether to scrub the third Moonwalk and it was Bill Muehlberger, a professor of geology from the University of Texas, in his capacity as head of the Apollo 16 surface geology team, who spent much of the first night on the Moon convincing NASA brass to keep EVA-3. Flight Director Gene Kranz was also in favour of saving EVA-3, but for different reasons. He had seen Dave Scott and Jim Irwin push themselves beyond the limit on Apollo 15, when their timeline had been shortened, and they had exhausted themselves in a bid to get everything done. Kranz was worried that Young and Duke would do the same and that would impair the mission.

Already, the late landing meant that they were unable to take telephoto pictures of a nearby landmark, Stone Mountain, in the early lunar morning. However, there was still much to do, and John Young quickly set to work on an automatic telescope camera to photograph ultraviolet emissions from stars, Earth itself and the lunar horizon. Next came the lunar rover, unfolded from its berth in Orion’s descent stage, and finally the US flag, which was planted in the soil. The main purpose of EVA-1, however, was to assemble the Apollo Lunar Surface Experiments Package (ALSEP), which included an investigation to measure heat flow within the Moon’s interior. Developed by geophysicist Marcus Langseth of Columbia University, the heat-flow experiment was originally aboard Apollo 13 and a subsequent flight on Apollo 15 generated limited data when the astronauts’ drill proved unable to dig to the required depth for its probes. Now, on Apollo 16, with an improved drill, Charlie Duke needed only ten minutes to bore the first of two holes into the surface and implant the first set of thermometers for Langseth.

As Duke worked, Young was finishing his own task at the ALSEP central station – the boxy unit which provided power to the other experiments, which included Langseth’s study, together with passive and active seismometers and a magnetometer. Each experiment was connected to the central station by bright ‘ribbons’ of cable. As Young moved away, his boot accidentally caught the cable for Langseth’s experiment and tore it loose. The bulk of his suit meant that he could not easily see his feet and both Young and Duke had warned engineers, before launch, that the cables refused to lie flat after deployment and this might cause a problem. As engineers and backup commander Fred Haise set to work on possible solutions, the astronauts had little choice but to continue their other tasks.

John Young works on the rim of Plum Crater, a yawning basin, some 40 m across and 10 m deep. On the far side of the crater, the lunar rover is barely visible. Photo Credit: NASA

Despite having expected to find extensive evidence of ancient volcanism, it was steadily becoming apparent that the site was instead littered with breccias – a type of rock composed of a mixture of fragments ‘welded’ together by the temperatures and pressures associated with a major impact – and Bill Muehlberger and his team were perplexed. The Cayley Plains were not shaping up to expectations. Geologists had predicted scarps, maybe four or five metres high in places, but with the Sun behind them the surface was transformed into a bright, washed-out, featureless blanket. As Young drove the rover, he could not even see the tiniest craters until he was literally on top of them. Anxious to avoid driving over a scarp, he pushed the rover no faster than four or five kilometres per hour, but no precipitous drops materialised. “We never encountered any of these features on the geology map,” Young reported in his post-flight technical debriefing. “They were mapped as scarps of steep features that said we were going to have to drive around or over. We just never ran into those.” In Young’s mind, the geologists had over-analysed some of the photographic plates and overestimated the extent of some surface features.

After examining Flag Crater – a large basin, 350 m across – the astronauts made the short trip to Plum Crater, which was thought to harbour rocks from whatever impact had created Flag. By 5:00 pm EST, some five hours into EVA-1, they had found nothing volcanic as breccia after breccia entered their sampling bags. At one point, Young got everyone’s pulses racing when he spotted what he thought was a welded ashflow tuff – a rock composed of ash fragments in a matrix of volcanic glass – but upon closer inspection it turned out to be another breccia. Before leaving Plum, another rock was collected…a rock so large that it probably weighed a full 10 percent of the 90 kg limit that Orion could carry. To get it, Duke had to get down in the dust, roll the monster onto his knee and then try to stand up again. When it was weighed, it tipped the scales at 12 kg and came to be known by the nickname of ‘Big Muley’, in honour of Bill Muehlberger.

Buster Crater came next, but by this point it was apparent that the water coolant in Duke’s suit was being consumed at a faster pace than anticipated and EVA-1 was curtailed. By 6:00 pm EST, the astronauts were back at Orion after a day of mixed fortunes. Some geologists had begun to rethink the possibility that the Cayley Plain and Descartes was volcanic at all or, at the very least, it was very well masked under a surface layer of impact rocks. By the time they repressurised Orion’s cabin, Young and Duke had been outside for over seven hours and had gathered 20 kg of samples. After removing his helmet, Duke was instantly captivated by the smell of the Moon…and, peculiarly, its taste. “It had a greasy feel,” he told Eric Jones for the Apollo Lunar Surface Journal. “It really magnified your skin oils, but it was picking up your skin oils, because there is no moisture in the stuff.” The taste and smell reminded Duke very much of wet gunpowder.

John Young takes the lunar rover for its first journey on the surface. Photo Credit: NASA

Other smells had affected the crew throughout the mission. During Apollo 15, the previous year, Dave Scott and Jim Irwin had displayed heart irregularities and doctors reasoned that this was due to a lack of potassium. As a consequence, Young, Mattingly and Duke flew to the Moon with an overstocked supply of potassium-laced orange juice. It did not taste particularly good and Young was first to announce that the thick, heavy, almost ‘metallic’ stuff left the three of them feeling gassy and nauseated. Gene Kranz tried some. His judgement? “It tastes like crap!” That crap was now affecting the two Moonwalkers in Orion’s cabin, when, added to the dirt and grime of the lunar dust, and the permeating odour of gunpowder, ‘other’ odours took centre stage.

Unfortunately, they also took on the world stage, for Young had accidentally left his microphone button in the ‘On’ position and his audience was treated to a full and frank discussion from two uncomfortably acid-stomached astronauts on the Moon.

“I got the farts again, Charlie,” Young began. “I don’t know what gives ‘em to me, I really don’t. I think it’s acid in the stomach, I really do.”

“Prob’ly is,” agreed Duke.

It was fellow astronaut Tony England, the capcom in Mission Control, who finally intervened to advise the embarrassed Young that the world could hear his every word. Needless to say, the communications between the men placed decidedly less emphasis on bowel movements for the remainder of the mission.

The final part of this article will appear on Sunday

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