Category How Apollo Flew to the Moon

The lunar day. as measured from sunrise to sunset, lasts for about 14 Earth days and therefore, the crew’’s circadian rhythm had to be maintained artificially. When it was time to sleep, the best that could be done was to put shades up over the LM’s three windows while the unfiltered Sun, rising slowly in the east, beamed down on the spacecraft’s exterior.

Unfortunately, the first three crews on the surface had to remain in their suits for the duration of their stay. The LM’s operational lifetime w? as very short, there was concern about the effect of dust on the zippers and the additional time required to get out of and back into their suits was considered too expensive. They simply had to endure an uncomfortable rest period. Once Armstrong and Aldrin had discarded their PLSSs out of the cabin, they could arrange things for the night. Aldrin lay across the floor in front of the hatch, his knees bent to allow for the confined space. Armstrong perched himself on top of the ascent engine. His head was towards the back of the cabin near a noisy coolant pump while his legs dangled above Aldrin supported by a lash-up he had fashioned from a cord in the spacecraft.

Their attempt to put the lights out was less than successful. Armstrong noted after the flight that, on top of the fact that the shades turned out to be not as opaque as they w’ould have liked, there w’ere several warning lights and luminous switches that could not be dimmed. And there was a final, more troublesome source of light. "After I got into my sleep stage and all settled down, I realised that there was something else shining in my eye. It turned out to he that the Earth was shining through the [telescope] right into my eye. It was just like a light bulb.”

They had elected to sleep with their helmets on in an attempt to limit the noise from the spacecraft and to keep front breathing the pervasive dust. But now that they had settled down and were no longer active, they began a battle with the environmental control system to stay wann. “We were very comfortable when we completed our activities and were bedded down.’’ continued Armstrong. "After a while, I started to get awfully cold, so I reached in front of the fan and turned the water temperature to full up. It still got colder and colder. Finally, Buzz suggested that wc disconnect the water, which 1 did. I still got colder. Then. I guess, Buzz changed the temperature of the air flow’ in the suit.”

The next two crews fared only a little better, even though they didn’t get cold, thanks to procedural changes after Apollo 11, and they had hammocks across the cabin to make their rest more comfortable. Conrad had made a small error with the sizing of his suit shortly before the flight and he paid for it during his rest period with the resultant pressure on his shoulders. Bean then spent an hour making adjustments to the legs of Conrad’s suit to relieve the pressure.

Bean also struggled to get some proper rest as he explained after the flight. "I think I didn’t sleep well because I was just nervous and excited.” How’ever, there was a solution in the medical kit, if he chose to use it. "If 1 did it over again, 1 would take a sleeping pill on the Moon." Bean’s explanation hinted at the issues NASA would have to deal with before the J-missions began, each involving three 7- hour EVAs. "I felt like I was tired towards the end of the second EVA and I felt like it w’asn’t from the physical effort. It was from the lack of good sleep. I didn’t take the pill because it was not a macho thing to do, [but] 1 felt like 1 was really running out of gas.”

The problem for the Apollo 14 crew’ was that the LM had settled with a 7” tilt that was enough to upset their sense of up and down in the dark, as Mitchell described after the flight: "We both had the feeling throughout the night that the blasted thing was trying to tip over on us. Actually, w’C got up and looked out the window a couple of times to see if our checkpoints w ere still right w’here they were supposed to be.”

Whereas the first three landings got away w’ith a single rest period on the Moon, it was NASA’s intention that the. І-mission crews w’ould stay on the surface for up to 72 hours. If a crew’ were to be expected to work at a high level of physical effort and mental concentration; to make a landing, spend three days on the surface and then guide their ascent stage to rendezvous with the CSM then, during three rest periods on the Moon, the suits w’ere going to have to come off.

To practise for this, Scott and Irwin even stayed a full night in the LM simulator in Florida starting w’ith a simulation of a landing. "We had it as high a fidelity as wn could possibly get it. So we had everybody put everything in the simulator down to the last detail.” He continued, "We got a terrible night’s sleep. I mean, boy, that’s crummy, trying to sleep in those hammocks in one g in that little thing. We did the suit doffing and everything. Of course, the suit doffing was such a pain, anyway, especially in one g. But it really paid off because, w’hen we got to the Moon we were very comfortable in doing that sort of thing.”

Doffing the suits made all the difference to sleeping in the LM. Crews found one – sixth-g to be very comfortable as they had enough weight to lie normally in the hammocks but not enough to cause pressure points. ‘‘I slept much better on the lunar surface than I did in orbit," remembered Jack Schmitt. "One-sixth gravity is a very pleasant sleeping environment with just enough pressure on your back in those hammocks to feel like you’re on something but not enough to ever get uncomfortable. 1 slept but my impression was that I only needed about five hours sleep to feel rested whereas ordinarily on Earth at that time I usually felt that I could use seven. But I think that’s related mainly to the lower gravity environment. You just don’t get physically as fatigued as you would on Earth. You get as fatigued mentally obviously you’re working just as hard with your neurons but physically you don’t work as hard.”

All subsequent Apollo landings included time to deploy a full ALSEP, each consisting of a varying set of instruments cabled to a central station, all of it powered by a radioisotope thermoelectric generator (RTG). This was an early example of the type of power supply that would energise a generation of probes to the outer planets.

The Apollo RTGs used the radioactive decay of plutonium-238 to generate heat which was directly converted to electricity by an array of thermocouples. The presence of plutonium on the spacecraft had certain repercussions. It could not travel to the Moon in the RTG for fear of contamination if there were to be an accident near Barth. Instead, it was packaged into a fuel element or capsule which was transported to the Moon inside a graphite cask mounted vertically on the outside of the descent stage where it could radiate its heat. This cask was strong enough to withstand re-entry through Barth’s atmosphere and, thanks to this ability, the Apollo 13 plutonium now lies at the bottom of the Tonga trench in the Pacific Ocean.

Once on the Moon, it was the LMP’s task to remove the plutonium fuel capsule from its cask and insert it into the body of the generator. Alan Bean w as the first to try this and ran into problems when reality failed to match any Barth-bound trials. First he hinged the cask down to gain access to the removable dome at one end. then he removed it with a special tool.

’’There you go,” said Pete Conrad encouragingly.

”It came off beautifully.” said Bean. ‘ [I’ll] put the tool and the dome aside.”

This had started well. Next he had to engage the capsule removal tool. “Go ahead,” said Conrad.

“There you go.” commented Bean. “Sliding right in there. Okay. [I’ll] tighten up the lock.”

With the tool firmly engaged, Bean pulled on the capsule, only to discover that it wasn’t going anywhere. “You got to be kidding,” he exclaimed.

“Make sure it’s screwed all the way down,’’ suggested Conrad.

Bean was caught between wanting to give it a good yank but not wanting to break the mechanism that attached the tool to the capsule. Gear that w? ent to the Moon was built as light as possible. There wouldn’t be much strength in reserve.

“Thai could make a guy mad. you know it?” moaned Bean.

“Yup,” replied his commander.

“Let me undo it a minute, and try it a different way.”

“Yup.”

“It can really get you mad."

Bean reinserted the tool with its prongs rotated to use different slots.

"You guys got any suggestions?” asked Conrad of the folks in Hous­ton.

"I just get the feeling that it’s hot and swelled in there or something,” Bean said as he tried again to extract the capsule. "Doesn’t want to come out. I can sure feel the heat, though, on my hands. Come out of there! Rascal.”

The capsule was seated within two steel rings that held it away from the graphite cask. It seemed that, with it giving off 1.5 kilowatts of heat, the expansion of the arrangement was holding it snug on the rings.

"You know, everything operates just exactly like it does in the training mock-ups and up at GE (General

Electric Corporation). The only problem is, it just won’t come out of the cask. I am suspicious that it’s just swollen in there or something and friction’s holding it in. But it’s such a delicate tool, I really hate to pull on it too hard.”

Unfortunately engineers had not fully taken account of the length of time that the capsule would sit in its cask from Florida to the Moon, its 700°C heat soaking the steel mounts.

Bean piped up. “Go get that hammer and bang on the side of it.”

“No. I got a better idea,” said Conrad. “Where’s the hammer?”

“That’s what I said.”

“No, no. But I want to try and put the back end in under that lip there and pry her out. Let me go get the hammer. Be right back.” Conrad’s idea was to use the hammer’s blade to lever the capsule out.

“Let me get the tool off,” said Bean as he felt the capsule’s heat move along the handle. “It’s starting to warm up.” He disengaged the tool as Conrad went around the LM. They were not unduly bothered by the radiation from the capsule. It was alpha radiation and as such, was stopped by a small amount of material. They would not be exposed to it for long anyway. Their real concern was that the thermally hot capsule might damage their suits. They had to use the tool to extract it. Once Conrad had retrieved the hammer. Bean re-engaged the tool with the element. They were both leaning towards a little percussive persuasion.

Bean spoke first. "Now, my recommendation would be pound on the cask.” He preferred that Conrad not use the hammer’s blade on the capsule. As Bean pulled on the tool, Conrad began to repeatedly hit the side of the cask with the hammer.

”Hey, that’s doing it!” yelled Bean excitedly as the cask began to yield its contents. "Give it a few more pounds. Got to beat harder than that. Keep going. It’s coming out. It’s coming out! Pound harder/’

“Keep going/’ commanded Conrad to the balky capsule.

‘’Come on, Conrad!” laughed Bean.

"Keep going, baby."

“Thai hammer’s a universal tool.”

“You better believe it/’ cheered Conrad.

With every thump, the capsule edged out until, after a few centimetres, it came away easily. To Conrad’s giggles. Bean swung it over to the RTG unit.

"That’s beautiful. That’s Loo much.” said Bean.

“Well done, troops/’ congratulated Ed Gibson, Capeom in Houston.

“We got it, babe!" explained Bean. “It fits in the RTG real well! It’s just the cask was holding in on the side. Don’t come to the Moon without a hammer.” He brought the hammer home to Earth and now uses it to texture his paintings in his post-Apollo life as an artist.

Deployment of the ALSEP required a reasonably flat site a few hundred metres from the LM. The complete kit was mounted on two pallets and stored on rails in the LM’s descent stage. Once lowered to the ground by pulleys, the packages were hung on a bar bell and carried to the site. The layout was roughly star-shaped with ribbon cables that radiated out from the central station to the various instruments. Each cable was on a reel which fed out both ends simultaneously. There were often stringent constraints on the placement of each instrument, requiring care to avoid interference between instruments and to minimise heat conduction with the ground. For example, the magnetometer had to be clear of other instruments that contained magnets. Also, the seismometer was mounted on a stool surrounded by a reflective Mylar skirt that kept the Sun from heating the ground because the expansion and contraction from the heating cycles w’ould have added noise to the instrument’s output. However, the skirt itself routinely added unwanted signals each morning when the Sun first hit it and caused it to flex and buckle in the heat.

Prior to deployment, the various instruments were attached to their pallet by ‘Boyd bolts’, spring-loaded fasteners that required a crewman to insert the end of their universal hand tool (UHT) and give a fifth of a turn to release them. To help the crew7, each bolt had a collar that guided the tool to the bolt. In general, the bolts worked well but on some occasions, what had seemed simple on Earth became much more difficult in the dust and light gravity of the Moon.

“Another one of those beautiful Boyd bolts is all full of dust,” muttered Shepard

Assembled panorama of Apollo 17’s ALSEP after deployment. RTG is on the left, central station to the right with its antenna aimed E <i+hward. (NASA)

sardonically as he tried to release a small instrument, the supra thermal ion detector, from its pallet.

‘’Yep,” agreed Mitchell. "’Everything else is going to be full of dust before long. Be filthy as pigs."

Shepard first tried the obvious solution. "Tm going to have to lift it up and shake the dust out of that Boyd bolt; I can’t get it otherwise. Let’s just turn it upside down and shake it.’’

As they lifted it. parts fell away. "Well, there’s a lot of Boyd bolts falling off,’’ said Mitchell, referring to the parts of the bolts that Shepard had already unfastened.

"Yeah, but them’s not the ones we’ve got the problems with. Okay, flop it over a minute."

‘"That’ll do it?" asked Mitchell hopefully.

"No, it’s still not clear.’’

Shepard was having problems on three levels. Lunar dust gets everywhere and having found its way into the Boyd bolt, its cohesive nature in the vacuum helped it to stay there. Additionally, the weakness of the lunar gravity gave little assistance in clearing the bolt’s sleeve, even when Shepard turned it upside down. The situation was exacerbated by the bolt being relatively inaccessible and, as Mitchell would later explain, it was difficult to see what was happening. “On the lunar surface, there’s no air to refract the light in there. So, it’s either shadow or it’s light and, unless you’ve got a direct sunlight on it, there’s no way in hell you can see anything. That’s an amazing phenomenon on an airless planet. It’s amazing how much we count on reflected and refracted light here. But there, unless you had it directly in sunlight, it was just pitch black. And that’s what he was wrestling with, there. The dirt was packed in around it and, besides that, he couldn’t see dowm in there unless we picked it up, physically, and twisted it and held it so we could get it in the sunlight."

That one bolt cost Shepard nearly ten minutes before he finally got it loose. David Scott later discussed how important it was for something that small to work correctly. "In a training context, especially [as Apollo 12 backup commander]. I remember trying to get the Boyd bolts to work, and they would hang up. One would hang up, and you couldn’t deploy the ALSEP. Or, the UIIT’s hexagonal probe that goes into the socket w’ould sort of strip and get w’orn and you couldn’t turn it. And, if you turned it too hard, you’d strip the edges. The Boyd bolts were challenges. I think all ours w’orked just fine. But the UIIT and the Boyd bolts w’ere a big deal; because, if it didn’t work, then you didn’t get that piece of the ALSEP up. And there were a lot of Boyd bolts."

Across the six missions that landed, crew’s deployed a large number of instruments as part of the ALSLP or as standalone experiments. Seismology was a popular topic, with passive seismometers being carried on most missions. Some missions included active seismometry. with small explosive charges being set up to provide calibrated shockwraves that w’ould help to profile the local subsurface. Magnetometers sensed the local magnetic held which, on the Moon, was dominated by its monthly passage through Earth’s magnetotail. However, because some of the Apollo 11 rocks proved

to be magnetic, some later missions included a portable magnetometer to measure remanent magnetic fields at points along a traverse. Many experiments tried to sense and characterise the various particles that comprised what little atmosphere the Moon possessed. Most of these were from the solar wind or from the rocket exhaust of the spacecraft, but there was also the question of whether the change from night to day, and the resulting rise in ultraviolet exposure caused tiny particles of charged dust to levitate for a while.

There were experiments on the mechanics of the lunar soil which acted in ways that were not foreseen. Though the top layer was extremely loose and powdery, its characteristics changed markedly just a few centimetres below the surface. Millions of years of slow settlement had caused it to become extremely tightly packed and crews sometimes found it difficult to drive in items like flagpoles and the solar wind collector. Trenching experiments showed that the vacuum and the very finely ground nature of the powder made it remarkably cohesive and able to support steep sides. Even Buzz Aldrin’s famous bootprint photograph showed how well the powder could hold an impression.

There was an ultraviolet telescope on Apollo 16, a device for measuring the local gravitational field mounted on Apollo 17’s rover, and experiments to determine the electrical properties of the lunar surface. Add to all this the intense expeditions to photograph, document, sample and generally geologise across their site, this feast of science kept all the Apollo surface crews extremely busy for their precious hours walking on the Moon. One particular ill-starred experiment served to teach everyone about the difficulties of trying to carry out science in a vacuum, under an unfiltered Sun into a poorly understood, extremely dusty and abrasive soil while wearing in an awkward pressure suit with limited visibility. This was the heat-flow experiment.

Drill problems and the heat-flow experiment

Geophysicist Marcus Langseth was good at taking Earth’s temperature and now he had a chance to take the Moon’s. More specifically, he wanted to accurately

measure the temperature of the lunar soil at various depths. From these measurements, he hoped to calculate how much heat was flowing out of the Moon’s interior and infer whether its core is still molten. He designed an experiment for Apollo 13’s ALSEP that would place temperature probes into drill holes. The equipment burned up in Earth’s atmosphere after that mission’s LM had served as a lifeboat for its crew.

Langseth had to wait over a year for the Apollo 15 crew to try again. Using the father of the cordless drill, the experiment required two holes, each nearly three metres deep into which the probes would be inserted. Separate from the experiment, the drill would also be used to extract a deep core of material that would give geologists a record of the depositional layering of the soil potentially going back hundreds of millions of years.

Scott quickly found the drilling to be hard going and could only get the first hole down to 1.6 metres. He tried putting his weight on the drill but in the Moon’s weak gravity, this provided little push and, if anything actually worked against the design of the drill stems and their helical external flutes. At any rate, the designers had not taken sufficient account of the nature of the Moon’s surface. Although the Moon is draped in a blanket of finely ground-up rock – the regolith – which is many metres deep at the landing sites, the highly compacted nature of all but the uppermost few centimetres made it more like hard rock. Worse, the flutes at the joins of the drill stems had been narrowed to strengthen those joins but, with the dust unable to go anywhere else, it caused the stems to jam. Mission control agreed that Scott should place the probes in the existing hole even though it compromised the quality of the experiment. The second hole fared worse and at one metre, they decided to revisit it the next day. On returning to the site, Scott tried to lift the drill and rotate it to help clear the flutes but unbeknownst to him this actually caused the bit to disengage

from the stem above. Subsequent drilling with the hollow upper stem merely created a core running down alongside and when Scott inserted the probes they penetrated no further than about one metre.

With the heat-flow probes less than ideally placed, Scott began to drill a deep core sample using hollow stems which meant the material in the hole would be kept rather than pushed aside. Also, the flutes were of uniform depth and much faster progress was made. Scott readily reached 2.4 metres in depth, much deeper than the other two holes but by this time, they needed to return to the LM and leave the extraction to the final day. Much time and frustration had already been expended on the drilling.

On the final day, Scott learned that extraction of the deep core was to take precedence over their final drive to Hadley Rille and a feature known as the North Complex, a possibly volcanic site of some interest to Scott and the geologists. Usually rover drives came first so the crews would have more consumables available in case they had to walk back from a stalled vehicle. The decision to favour the drill meant that there would be no visit to the North Complex. However, when they tried to remove the core, it proved difficult to budge. Both Scott and Irwin had to work to extract the core, first by pulling hard on the drill’s handles, and eventually putting their shoulders under the handles and shoving so hard that Scott managed to injure his shoulder. It was a measure of the confidence that the crews had in their suits that they felt they could expend maximum physical effort without fear of a rip dumping their air.

"It shows how tough and durable the things were,” remembered Scott when reviewing the incident years later. "I’m really surprised that somebody in the back row in Houston didn’t get real squeamish about all of this. I’m surprised some boss didn’t just say. ’Hey, just knock that off.’ because they could hear us grunting and groaning – two guys on the Moon in pressure suits doing this kind of stuff. In retrospect, not smart, from a safety point of view.”

How ever, their suits included systems to warn of problems with the air pressure or cooling. ‘’Only if a tone comes on do you do something.” continued Scott. “As long as there are no tones, you work as you would work on the Earth and you never really think about [the dangers], Houston, that’s their job. To sort of pace us and guide us, because once we’re out in the suits, boy, it’s very comfortable."

Eventually, Scott and Irwin extracted the deep core but Scott’s troubles were not over and he was getting frustrated at the time being spent on it. "Joe, I haven’t heard you say yet you really want this that bad.” Joe Allen was the tactful Capcom in mission control. As part of his job, he acted as a go-between for the crew and the geology team in the science back room. ‘’Tell me you really want it this bad.” implored Scott. “It’s hard for me to say. Dave," was Allen’s wistful reply.

The six-part core stem, including a treadle that had helped guide the stem into the soil, all had to be taken apart for return to Earth. To help, a simple wrench vice that gripped in one direction was on the rover. Scott was having difficulty getting it to work. ‘‘This vice just won’t hold. There’s something wrong with it." They needed that wrench because a suited hand does not have much grip. It is already working against the suit pressure trying to straighten it “My hand wrench works okay. The one on the back of the [rover] doesn’t seem to want to work for some reason. It may just be because of the threads on the stems. I just can’t get them broken apart!” As Scott struggled with the stem in the vice, it dawned on him what the problem was. "I hate to tell you. Jim, but that… Oh boy! This vice is on… I swear it’s on backwards.” In fact, a reversed diagram in the assembly manual had thwarted them. The wrench had indeed been mounted back to front.

With Irwin’s help. Scott managed to separate half of the segments, even though it meant gripping the stem’s sharp flutes, yet the final three refused to come apart.

“We might be able to return it just like that.” suggested Irwin. Although it was 1.5 metres long, they would be able to get it in the LM.

“I don’t know where we’re going to put it in the command module.” said Scott. "I guess we ought to take it back. There’s more time invested in that than anything we’ve done.”

When the deep core reached Earth, it was immediately x-rayed which revealed 58 distinct layers within the core. Grant Heiken, a scientist who painstakingly analysed each layer, grain by grain, described it as the most valuable sample returned from the Moon.

The Apollo 15 heat-flow experiment gave good results despite its problems and created enough interest in Langseth’s experiment for another to be taken on Apollo 16. All the lessons from Scott’s battle with the drill and wrench had been learned. Using redesigned drill stems, Duke had no problem drilling the holes and inserting the temperature probes.

“Mark has his first one. announced Duke. "All the way in to the red mark [on the rammer] on the Cayley Plain.”

“Outstanding!” replied Tony England. “The first one in the highlands.”

Moments later, John Young lifted a package away from the central station and as he walked, his feci got caught up with the cable leading to the heat-flow electronics package.

“Charlie."

“What?"

“Something happened here."

“What happened?"

“I don’t know." said Young. “Here’s a line that pulled loose."

“That’s the heat-flow," Duke informed. “You’ve pulled it off."

“God almighty." Young’s spirits dropped like a stone as he went to examine the damage closely. The wires at the end of the cable had been torn from its connector where it was plugged into the central station.

“Well, I’m wasting my time," said Duke as he realised there was no point in drilling the second hole for the heat-flow probes.

“I’m sorry. I didn’t even know, said Young. "Agh; it’s sure gone."

“Okay, we copy," said England in Houston as the engineering back rooms began to crank up in a futile effort to resurrect the experiment. “I guess we can forget the rest of that heat flow."

“Yeah," replied Duke. “I’ll go do the [deep core]. Oh. rats!"

In fact, it was surprising there were not more accidents like this. Having the RCU mounted on his chest afforded the astronaut almost no visibility of his feet and the numerous layers in the suit’s construction severely attenuated any sense of touch. He constantly had to work against the internal pressure and its tendency to return the suit to one stance. This made it difficult for Young to have seen or even to have felt the snagging cable. Additionally, in lunar gravity cables tended not to lie as flat as they would on Earth and they ’remembered’ their coiled-up shape to form numerous loops spiralling across the lunar dust.

After more than 2 ‘/■ years. Marcus Langseth finally triumphed when his heat – flow experiment was fully installed at Taurus-Littrow by the Apollo 17 surface crew. The measurements from the two sites where emplacement was successful showed that the Moon has little residual heat of its own. What heat it has is produced by radioactive decay in the topmost few hundred kilometres but it is insufficient to cause substantial melting of the lunar mantle.

Once NASA had accepted UOR as the Apollo mission mode, they had to work out how a rendezvous, whether in Earth or in lunar orbit, should be accomplished. The problem was far from straightforward, and the solution did not spring forth from the mind of some brilliant engineer. Rather, it evolved from 1964 right through to the first landing and eontinued to evolve throughout the programme. The problems were many. Some of the major factors with w hich they had to contend were:

• how accurately w’ould the engines perform?

• how would a crewman know his speed and the speed of the target spacecraft?

• w’hai should the lighting be during the delicate docking manoeuvre?

• what is the least amount of propellant required in the pursuing spacecraft?

• how high should the target spacecraft be orbiting?

• how long should a rendezvous take?

NASA first considered a direct ascent technique, but quickly dropped it. For the Gemini programme, the step-by-step approach of the coelliptic rendezvous was developed. As Apollo crews and engineers worked to improve performance, they devised the confusingly named direct rendezvous or short rendezvous.

"What’s the time?” asked Aldrin from Columbia’s right-hand couch. The crew of Apollo 11 had made their attitude checks prior to TEI. and were verifying that the engine bell was swivelling on its gimbal correctly in response to steering commands. Preparations were going smoothly and there was a light mood in the cabin as their incredible flight began to look as if it might actually come off.

“We have 12 minutes to go.” replied Collins, occupying the left couch.

Aldrin had been wondering what they should do once TEI w as completed: “You going to pitch up after the burn?”

“Sounds like a good idea,” agreed Collins. “Let’s look at the Moon after the burn. That’ll give us high-gain, right?”

“Cheek,” concurred Aldrin. Since they needed the spacecraft’s high-gain antenna to face Earth and it was positioned on the opposite side from their windows, it made sense to point the spacecraft down to have the high-gain in a favourable position for Earth and. meantime, watch the Moon recede.

“Okay, 10 minutes until Tig,” called Armstrong. ‘Tig’ was the ‘Time of ignition’ and everything they did worked towards it being on time and as flawless as possible. As they were over the far side of the Moon, where it also happened to be lunar night, neither the Sun nor Earth was shining across the landscape, and the only way to see the Moon’s position was by looking at a huge void where there were no stars. The spacecraft had to be travelling with its apex forward to enable the engine at the rear to accelerate them out of lunar orbit, and Collins was straining at the window for some kind of confirmation of this fact.

“I see a horizon,” he laughed. “It looks like we are going forward.”

“Shades of Gemini.” reminded Armstrong.

“It is most important that we be going forward,” stated Collins.

Aldrin began gently mocking his crewmate. “Let’s see. The motors point this way and the gases escape that way. therefore imparting a thrust that-a-way.” They all laughed.

This was a chance to pause and reflect during their preparations, and to look for the horizon that they were supposed to check in a few; minutes.

“Beautiful looking horizon." said Armstrong. “It’s hard to describe."

“God, it has an eerie look to it,” added Aldrin. “It’s not a horizon, it’s just a band.”

Collins and Aldrin could sec directly forward through their rendezvous windows

along the plus-.v axis and towards the sunrise. Armstrong’s view from the middle couch was limited to the hatch window just above his head.

‘’It was really eerie when it first came/’ said Armstrong as the Sun rose and the terminator came into view. "And the way the terminator is, you don’t see the whole Moon at all."

"I know.” said Collins. "I was looking at it upside down for a while.”

"Yes, and then that scares you,” added Armstrong, "because that says you’re going retrograde, right? Well, let’s see. if it’s upside down, you’re going backwards/’ Collins brought them back to their checklist. "Alright, we’re coming up on bus tie time; we’ve got a little over 6 [minutes] 50 [seconds] until fig.”

The crew returned to the protocol of challenge and response, with Armstrong reading out a line from the checklist and Collins repealing it once he had carried out the instruction. Once they had dealt with the internal configuration of the spacecraft it was time for another external check.

"Two minutes to get our horizon check at 10 degrees.’’ Armstrong had little option but to have his head in the checklist.

"Yes, and sneaking up on there, looks pretty darn good.” said Aldrin. "Looks like we’re darn near right.” The spacecraft was holding a steady attitude with respect to the stars so, in a sense, the Moon appeared like a great, rounded hill and they were in a helicopter approaching the summit, ‘fhe Moon’s horizon crept down Collins’s window towards the 10-degree mark. Aldrin’s window did not have that mark but he could infer it. "Okay, coming up on two minutes.” he eallcd, "and this damn horizon check is going to be. would you believe, perfect?”

"I hope so,” said Armstrong.

"fantastic,” enthused Aldrin. "First lime we ever got a perfect horizon check. Spent too many hours in the simulator looking for an unreal horizon. Alright, horizon check passes.”

"Beautiful,” agreed Collins, who armed one of the engine’s control banks then proceeded with Armstrong through the final lines of the checklist.

"Okay, stand by for 35 seconds,” announced Collins. "Mark it. DSK. Y blanks; EMS is in Normal.” The guidance system had begun to measure their acceleration. Aldrin came back, "Check.”

"Coming up on 15 seconds,” said Collins.

Armstrong readied himself at the computer keyboard for when the display w ould start flashing ’99’ at him, asking for permission to light the engine. "Okay. I’ll get the 99.” – – –

"Okay,” said Collins. "Stand by for ullage. Ullage.’’

"Cot the ullage,” reported Aldrin. Two rearward-facing thrusters lit up, gently pushing the spacecraft forward and bringing the weightless propellant to the bottom of the tanks as the crew counted down.

"Burn!” shouted Collins as the SPS engine lit. "A good one. Nice.”

"I got two balls,” called Aldrin.

As planned, only two of the four ball valves on the propellant feed lines had been opened by the computer.

"Okay, here comes ihc other two.” said Collins as he threw the switch to bring in the second control bank and bring the engine to its maximum thrust. “Man, that feels like g, doesn’t it?"

When they fired the SPS engine on arrival at the Moon, the tanks in the service module had been full and the LM was attached to their nose. Now the CSM was by itself and its tanks were only one-third full, giving the SPS the ability to accelerate the spacecraft towards 1 g.

Collins was closely monitoring the displays in front of him. "Pressures are good. Busy in steering, but it’s holding right in there.’’

“Hotv is it. Mike’.’" asked Aldrin from the right.

"It’s really busy in roll," replied Collins, "but it’s holding in its dead band. Looks like it’s holding instead of plus or minus five, more like plus or minus eight [degrees]. It’s possible that we have a roll-thruster problem, but if we have, it’s taking it out. No point in worrying about it. Okay, coming up on one minute. Mark it, one minute. Chamber pressure’s holding right on 100 psi."

"Looks good," agreed Aldrin.

Collins continued with his commentary. "Gimbals look good: total attitude looks good. Rates are damped out. Still a little busy."

There was no problem with the roll thruster, but the sloshing propellant could have a significant effect on the spacecraft’s attitude which was corrected by the thrusters and the engine gimbals.

"Two minutes. Mark it," continued Collins. "When it hits the end of that roll dead band, it really comes crisply back." Collins was describing how well the computer was able to deal with the CSM’s tendency to drift off in attitude.

“Okay, chamber pressure’s falling off a little bit." Collins had one eye on the gauge that showed the pressure within the combustion chamber. "Now it’s going back up; chamber pressure’s oscillating just a tad."

Armstrong called out. “Ten seconds left.”

"We don’t care about the chamber pressure," said Collins. "Brace yourself. Standing by for engine off."

The 2 minutes 28 seconds that mission control had predicted for the burn came and went, but the engine was still firing.

“It should be shut down now’," said Armstrong.

Collins queried him, "Okay?"

“Shutdown," called out Armstrong.

Collins stopped the engine at the same time as the computer. It had burned for 3.4 seconds longer than predicted because its thrust during the LOI burn had been slightly high and mission control had used that data when planning TEI. In the event, a slight change in mixture ratio lowered the thrust and so it burned a little longer to achieve the same change in velocity.

"Let’s look at what we got," said Collins as they brought up the residual velocity components. "Beautiful," he commented, “,v and r, 0.2." A burn that had changed their velocity by 1,000 metres per second was showing an error of only six centimetres per second. "SPS, I love you," he exulted. "You are a jewel! Whoosh!"

As with the LOI burn, no one knew anything of this in the MOCR or anywhere else on planet Earth. Any communication with Columbia was blocked by a 3.476- kilometre ball of rock. What they did know in mission control, down to the second, were the limes when the CSM would come back into view if the burn had worked, and if it had not. The increase in velocity would dramatically shorten how long it was out of sight.

The first operational step in preparation for re-entry occurred a few hours out, when the crew stopped the spacecraft from slowly spinning on its long axis in the so-called
barbecue mode for the final time. The time remaining in space no longer warranted the protection provided by thisywM’.vive thermal control rotation. Once he had control of the spacecraft’s attitude, the CMP had a final chance to practise his techniques of navigation, partly in case communications were lost and the spacecraft had to make its approach without assistance from Harth. but mostly to provide yet another data point for engineers about the crew’s ability to fly autonomously. Prior to his exercise, he carried out his penultimate platform realignment.

On those later advanced missions that carried a SIM bay in the service module, the crew powered it down for the last time before the final correction burn opportunity. As the film canisters had long since been extracted from the cameras, only a few instruments were still operating and. even then, they were only looking at deep space. Those mounted on the end of 7-metre-long booms were retracted except during the Apollo 15 mission when the booms were jettisoned – probably as an engineering test of that capability on their first outing.

It was around this point in the descent that the last Apollo command module to enter space ran into problems. During their return from the first international link­up in Earth orbit, the Apollo-Soyuz Test Project, the crew failed to switch on the Earth landing system at the right time. This episode illustrates how quickly an otherwise nominal mission can be derailed by a small operational error. Vance Brand was flying in the left couch with ‘l orn Stafford in command occupying the centre couch and working through the checklist with him. Somehow, they missed the step where the Earth landing system should have been powered and. all too quickly, they realised that the apex cover was still attached when it should have already departed. Brand punched the button to manually jettison it, and did the same for the drogue chutes. Unfortunately, in the rush, the RCS jets were not disabled, and when the drogue deployment caused the spacecraft to sway, the RCS jets began to lire to damp out these motions. By this Lime, the cabin pressure relief valve had begun to admit air from outside and, as it did so. exhaust from the jets, including a fraction of unburnt propellant, entered the cabin where the highly noxious chemical irritated the skin and eyes of the crew and caused them to cough. After struggling through the remainder of the descent and a hard landing that left the spacecraft upside-down. Stafford found Brand to be hanging in his straps unconscious. He struggled to get oxygen masks on his crewmates and gain control of the ship.

If a 24-sccond burn made around the Moon’s far side could lower the spacecraft’s near-side altitude from 300 kilometres down to only about 15 kilometres, it is easy to appreciate that an overburn of only a few seconds would so reduce the altitude that an impact with the surface could become a real possibility. The resultant precautions involved in the DOI burn are especially understandable in view of the fact that there was considerable uncertainty about the Moon’s precise shape, especially with regard to the more northerly regions that would later be overllown by two of the J-missions. Apollos 15 and 17, where some of the mountains reach four or five kilometres above the surrounding terrain.

As with all burns, the amount of delta-v was monitored by the crew via the DSKY. For a DOI burn, the typical delta-v was 210 feet per second (64 metres per second), which was the amount by which their velocity along the. v axis had to drop. One second of burn accounted for about 10 feet per second. As the burn progressed, they would see this value decrease towards zero. If the computer did not shut the engine down at the expected time, the crew had to promptly terminate the burn manually. They would then consult the DSKY to see if there was any overburn. The rules were that if they had slowed a mere 2.2 feet per second (0.67 metre per second) more than planned, they should immediately use their RCS thrusters to regain this speed. If they had overshot by as much as 10 feet per second (three metres per second), they were to turn the spacecraft around 180 degrees and regain the lost speed by firing a burp of the SPS.

Whatever the result of the DOI manoeuvre, once the crew were happy with it, they began to prepare for a possible bail-out burn. This was in case some other sign, in particular radio tracking from Earth, were to suggest they were at risk of impacting the ground. If so. they had at most an hour before the unthinkable would occur, and because they were over the far side at the time of the DOI burn, they would have no confirmation one way or the other for half of that time. The exquisite accuracy of radio tracking could only be brought to bear after AOS. with less than half an hour remaining to any theoretical impact. Therefore, w? hile the tracking stations measured their trajectory, the crew waited for a call from mission control to confirm that their orbit wasn’t going to spray them across some near-side mountain at over 5,000 kilometres per hour. This never became a real threat, and the crew’s and mission control felt confident enough with their hardware and procedures to view the bail-out burn as little more than a formality, but, in the NASA way, they were prepared for it.

In all instances, the two spacecraft were allowed to separate once the LM was well into the checkout of its systems and no problems were being encountered. For the later missions, Apollo 14 onwards, mission control read up a PAD with which the CMP could make his circularisation burn. In truth, the orbit that resulted from this burn was not really circular but was made deliberately elliptical. This reflected the fact that FIDO was compensating for the perturbation of the CSM’s trajectory by the Moon’s mascons, and although the effect of these gravitational irregularities was not well understood by the flight dynamics team, they hoped that by the time the LM was due to return, the orbit would have tended towards circular.

The descent orbit that the LM had been left in had its perilune over the near side, 500 km short of the landing site. Therefore, the eireularisaiion manoeuvre required a short burn of the SPS engine – lasting only about four seconds – to be carried out around the Moon’s far side which would lift the CSM’s perilune up to about 110 kilometres. For all SPS burns, an elaborate series of procedures had to be carried out to prepare and check the engine and its control systems. One of these checks was to verify that the gimbal-mounted engine could be aimed before and during the burn, and it was in making this check that a problem occurred that nearly cost Apollo 16 its landing on the Moon.

As Mattingly made his checks. Young joked to Duke at how things had begun to stack up against them; meaning the problems they were having with the steerable antenna and RCS pressures. "Charlie, this is fun, by golly,” he laughed. "It’s really the worse sim I’ve ever been in."

"It’s really bad, isn’t it.” agreed Duke.

The crews had become used to dealing with difficult scenarios during the many and varied simulations that comprised their training. But by the time they went on their flights, they were often struck by how calm things were because, for most of the time, things worked. The simulator supervisors w’ere no longer throwing obtuse scenarios at them to test how – they and mission control would respond. But to Young, this LM checkout w-as starting to feel like a particularly nasty simulation. Just then, Mattingly called across their VIIF link. "Iley, Orion."’

"You speak?” said Young. "Go ahead, Ken.”

"I have an unstable yaw’ gimbal number 2. It oscillates in yaw any time it gets excited.”

"Oh, boy,” said Young. Things were already bad but they had just got a lot worse. The SPS included a system called thrust vector control (TVC) that steered the engine during a burn. Mattingly had discovered that its backup mechanism was shaking wildly every time he tested it. They needed that engine to get home and this sounded like a show’-stopper.

"You got any quick ideas?” asked Mattingly.

"No, I sure don’t.” said Young.

Their mission rules said that the main and backup actuators for both the engine’s pitch and yaw gimbals had to check out as fully functional, or the crew – had to return home forthwith which would mean cancelling the lunar landing.

"I’m sure sorry about this,” said Mattingly, "but that number two servo is just oscillating like a wild man. It could be a switch here somew-here, but I sw’ear, I’ve checked them all I can. I guess I’ll power them dowm.”

"Yep, and tell the ground when you go around.” said Young.

"Okay,” replied Mattingly. "Brother, w’hat a way to start the day. huh?”

As they were still around the far side, Houston had no inkling of the problem until CSM Casper reappeared around the eastern limb. Meanwhile, Young brought Orion back tow’ards Casper to await Houston’s decision.

"Houston. This is Caspercalled Mattingly as soon as he had established communication with Earth. "We did not do Circ. and I’d like to talk about the TVC servo loops.”

“Understand. No circ." confirmed Jim Irwin.

Immediately, teams of engineers in Houston began to work the problems that had been reported for the two spacecraft, calling on support teams at the manufacturers in California and Long Island.

Young had psyched himself up for the landing and now it did not look like it was going to happen. “Man, I’m ready. he told Duke. “I’m ready to go down and land. 1 think thal’d really be neat.’’

Duke was not optimistic. "I bet we dock and come home in about three hours."

After four hours, when both spacecraft had gone behind the Moon for a second time since reporting the problem, managers decided that it was safe to proceed with the landing. Their rationale was that if the main actuators controlling the SPS engine were to fail, the backup system would kiek in. That is. they thought that its wobble did not threaten its primary function, that of bringing the crew home. Six hours later than planned, and about as long a delay as could have been accommodated. Young and Duke landed safely at Descartes. Although the extra hours spent in orbit had eroded the LM’s overall pow’er supply and the surface time had to be trimmed to suit, they completed an essentially full mission.

In the LPD, the engineers had devised a simple but powerful and ingenious way to tell the commander where P64 was taking them. It was as basic a device as you could hope to find in a high-tech spacecraft, though its operation depended on what was then one of the world’s most sophisticated small computers. It consisted of nothing more than vertical lines carefully scribed onto the inner and outer panes of the commander’s forward-facing w indow.

The lines calibrated the commander’s line of sight, as measured from a line directly forwards from his eye, downwards in degrees. To use it properly, he merely positioned himself in such a way that the two sets of lines were perfectly superimposed, which meant that he was in the proper position and their sight lines were valid. As the computer flew’ the LM to a landing, it displayed an angle on the DSKY that represented the line of sight to the expected landing site. The commander looked past the markings towards the surface and noted the terrain in front of him that coincided with the stated angle. That, at least, defined a downrange coordinate. Simultaneously, the computer would yaw the LM left or right so the line itself defined a lateral coordinate. The combination of the two pointed to the designated landing site. This lightweight but elegant solution also allowed him to redesignate the landing site by nudging his hand controller left, right, back or forward, and P64 would then aim the LM for the new target.

Immediately Conrad had his angle, he looked out his window to see w here it was aimed. “Hey, there it is!” he called excitedly as he recognised an arc of craters and, just before them, the Snowman. “There it is! Son-of-a-Gun! Right dow n the middle of the road!”

“Outstanding!” said Bean who then began feeding LPD angles to his commander. "42 degrees, Pete.”

“Hey, it’s targeted right for the centre of the crater!” enthused Conrad. “I can’t believe it!”

“Amazing!” agreed Bean. “Fantastic! 42 degrees, babe.”

After the mission, Conrad talked about this moment when their plans for an accurate landing came good. “For the first couple of seconds, I had no recognition of where we were, although the visibility was excellent. It was almost like a black-and – white painting. The shadows were extremely black, illustrating the craters; and, all of a sudden, when I oriented myself down about the 40-degree line in the LPD, our five – crater chain and the Snowman stood out like a sore thumb.”

With the departure of his two erewmates to the lunar surface, the CMP had a bigger space in which to move around so life on board the Apollo command module became somewhat more comfortable. Michael Collins elaborated on this extra space in his autobiography.

‘T have removed the centre couch and stored it underneath the left one, and this gives the place an entirely different aspect. It opens up a central aisle between the main instrument panel and the lower equipment bay. a pathway which allows me to zip from upper hatch window to lower sextant and return.” One reason that Collins created this extra room in the cabin was in ease his erewmates returned and found they could not get through the tunnel for whatever reason. All three men would be in their space suits and the two surface explorers would enter through the main hatch, clutching boxes full of rocks. Collins appreciated the extra room now afforded him: "In addition to providing more room, these preparations give me the feeling of being a proprietor of a small resort hotel, about to receive the onrush of skiers coming in out of the cold. Everything is prepared for them; it is a happy place, and I couldn’t make them more welcome unless I had a fireplace.”

Collins had a relatively short time alone in the command module, and much of it was spent on housekeeping duties or looking through the sextant in vain to find his colleagues on the surface. He also found that there was very little time available to speak with mission control. Only one communication channel was available between the Moon and Earth through a single Capcom and this was being dominated by the large amount of chit-chat from the guys on the surface as they talked to mission control and to each other. This became somewhat problematic as the needs of the orbiting CSM and its sole occupant vied for Lime on a link that was already busy with the important task of keeping two men alive and working on the surface of an airless world.

Richard Gordon on Apollo 12 had a similar experience, except that he had no problem finding the LM. given Pete Conrad’s pinpoint landing. Towards the end of Gordon’s Lime alone in the CSM, he did get to push the science possibilities of the orbiting spacecraft a little when he operated a cluster of four Hasselblad film cameras mounted on a ring, each loaded with black-and-white film and each shooting through a different filter. This cluster was attached to the hatch window and allowed him to photograph the surface in red, green, blue and infrared light. The idea was to detect subtle hue variations across the surface that would relate to the composition of the soil. Telescopic studies had shown that some mare surfaces had a slight reddish tinge while others were bluish. A similar experiment had been attempted on Apollo 8 when Bill Anders photographed the maria through red and blue filters. However, excessively fatigued. Anders had inadvertently installed a magazine of colour film on the camera instead of the black-and-white magazine required by the experiment.

After Apollo 12. NASA decided that the increasing complexity of the missions required there to be two Capcoms, one for each spacecraft. This was readily achieved since the MOCR was already partially divided between the LM and CSM monitoring functions and there were separate consoles for the LM systems (Control, who looked after the LM’s guidance systems and engines, and TELCOM, later TELMIJ. who oversaw its electrical and environmental systems, much as НЕСОМ did for the CSM).

As their crewmates laboured on the surface dealing with suits and geology in the Moon’s dust pit, the CMPs handled an incessant programme of data collection and observation, while they simultaneously cared for the spacecraft. In addition to their planned tasks, it was not unusual for the CMP to deal with requests from geologists for yet another observation, or for a flight controller to seek clarification of a nuance of the CSM’s operation. This could create a steady chatter over the airwaves during each pass across the near side.

“It turned out that my favourite experiment in orbital science was the bistatic radar," said Ken Mattingly after his Apollo 16 flight. T his experiment used the spacecraft’s communication antenna to beam radio energy at the Moon as the spacecraft passed across the near side while radio telescopes on Earth received the echoes. To work, the signal from the antenna transmitted only a carrier wave and therefore could not carry information. “That meant the ground couldn’t talk to me for an hour and a half. I had a chance then to go to the bathroom, eat dinner, and get an exercise period or look at the flight plan. I think you really need those kind of periods every now and then throughout the day.”

Occasionally the CMPs got Lime to enjoy the view and the experience of coasting across the Moon alone. Owing to the easterly position of the Apollo 17 landing site, most of the near side track was in lunar night, but it was a night time lit by an Earth that was much larger and far brighter than the Moon appears to us. “Boy.“ reported Ron Evans, “you talk about night flying, this is the kind of night flying you want to do, by the full’ Earth.”

“Is that right?” said Mattingly, now’ in the Capcom role in the MOCR.

“Beautiful out there,” said Evans as he watched the ancient landscape of the Moon drift by, illuminated by the soft blue-white glow of his home planet.

As America coasted over to the western limb, Mattingly warned that when Evans eamc back around he would read up a lengthy scries of updates to the flight plan to satisfy the geologists’ desire for further photographic coverage. lie then asked for a stir of the spacecraft’s hydrogen tanks. It was December 1972. midwinter on Earth’s northern hemisphere.

"You’re lucky you’re up there tonight. Ron. We’re having really ratty weather down here. Low clouds and rain and drizzle and cold.” said Mattingly.

"Oh, really?" replied Evans as he approached the edge of Mare Orientale. a spectacular impact basin barely visible from Earth and unrecognised until the 1960s.

"Yes. You walk outside, you just about can’t see the top of building 2.”

"Gee whiz! Guess I picked a good time to be gone.” said Evans.

“Thai’s for sure.”

Evans was enjoying the view when he spotted a flash on the surface, probably a meteor strike. "Hey! You know, you’ll never believe it. I’m right over the edge of Orientale. I just looked down and saw a light-flash myself.” Jack Schmitt had seen a similar flash just after they had entered lunar orbit.

"Roger. Understand,” replied Mattingly.

"Right at the end of the rille that’s on the east of Orientale.”

On Apollo 15. A1 Worden figured that since he was going to be reappearing from around the Moon’s far side every two hours, it would be a fitting gesture to greet the planet in a variety of languages to make explicit that he was greeting the whole Earth and its inhabitants, not just its English speakers. With help from his geology teacher. Farouk El-Baz, he wrote down the words, "Hello Earth. Greetings from Endeavour." phonetically in a selection of longues. Then, as he re-established communication with Earth, assuming that the pressure of work had relented enough, he would choose one of these languages as his way of greeting the world.

Worden found his time alone in the CSM to be busy but not unpleasant. When asked about how hard mission control would drive him after his rest break, he said, "It was not generally difficult to begin work in the morning, because I was usually awake by the time they called. Also. I spent roughly half [of my] time on the back side of the Moon, and so 1 had about an hour each revolution when 1 could not talk to Houston in any event. I was up and going before talking to Houston because I did not sleep that much during the orbital phase."

Another time, he recalled, "My impression of the operations of the spacecraft was one of complete confidence in the equipment on board. Things worked very smoothly, and 1 didn’t have to keep an eye on all the gauges all the Lime. The rest of the spacecraft ran just beautifully the whole time. The fuel cells ran without a problem. In fact, everything ran just beautifully, and I really had no concern for the operation of the spacecraft during the lunar orbit operations.”

Just being human

Everyone involved in Apollo’s exploration of the Moon was acutely aware that time on the lunar surface, or in lunar orbit for that matter. w:as gained at extraordinary expense, was extremely precious and had to be carefully rationed to gain maximum scientific return. Nonetheless, the human dimension, the sense of the occasion or our innate tendency to lighten things up a bit often managed to shine through. Every crew left objects behind, perhaps for future visitors to find or maybe just in the knowledge that something meaningful had been left behind on that extraordinary world. Like Worden’s greetings, Evans’ joy at flying in Earthlight or an impromptu ballet display that Jack Schmitt indulged in on the lunar surface, there would be moments of humanity that w ould turn these periods of relentless data gathering into something to which a wider audience could relate.

As would be expected, Apollo 1 l’s brief EVA was crammed with activity. Armstrong and Aldrin had to hustle to get everything done but time was set aside for a conversation between the crew and President Richard Nixon who spoke from the While House. Then, after they had conveyed their gear and samples up to the LM, Armstrong remembered one other item. “How about that package out of your sleeve? Get that?” He was still on the surface and Aldrin was in the cabin receiving the gear.

“No.”

“Okay, I’ll get it when I gel up there.”

“Want it now?” asked Aldrin.

“Guess so.”

Aldrin removed the package from one of his sleeve pockets and tossed it down to the surface where Armstrong positioned it with his foot.

“Okay?”

“Okay,” replied Aldrin, both men happy with its placement. The pouch contained patches and medals to honour space travellers – Russian and American alike – who had died, a gold olive branch to represent Apollo ll’s peaceful goals and a small silicon disk etched with messages from world leaders.

The seriousness of Apollo 11 gave way to the exuberant fun of Conrad and Bean just four months later. Their big idea was to smuggle a timer on board that would have operated their Hassclblad camera with a time delay. This would have allowed both crewmen to pose in front of the Surveyor 3 probe. They took great care to ensure the timer got to the Moon but when it came time for their surreptitious photograph, they could not locate it in the bag where it lay. By this lime, the bag was full of rocks and copious quantities of the tenacious dust that covered everything. Later, as they dumped the contents of the bag into a rock box next to the LM. the timer appeared. “That was when we should have done it,” recalled Bean years later. "We’d have had the LM in the background. We could have shook hands in front of the LM. It’d be the end of the HVAs. Been a great picture.”

On Apollo 14. A1 Shepard’s passion for golf inspired his stunt. Facing the TV camera at the end of his final EVA, he launched into his demonstration. “You might recognize what I have in my hand as the handle for the contingency sample return; it just so happens to have a genuine six iron on the bottom of it. In my left hand. I have a little while pellet that’s familiar to millions of Americans.”

Shepard dropped the smuggled golf ball and prepared to take a shot. The constraints of the suit forced him to swing his improvised golf club with one hand and on his first attempt he merely buried the ball in the dust.

“You got more dirt than ball that time,” observed Ed Mitchell.

“Got more dirt than ball.” agreed Shepard. “Here we go again.”

His second shot connected to move the ball about a metre, though in the wrong direction.

"That looked like a slice to me, Al,” said Fred Haise in Houston.

"Here we go,” said Shepard. “Straight as a die; one more.”

He was successful at the third attempt and also gave a second ball a clean hit, sending them both soaring into the distance.

"Miles and miles and miles,” he said as the second ball flew off.

"Very good, Al,” said Haise.

Mitchell also tried a little sporting activity during their final moments when he threw the support for the solar wind experiment, javelin style, as far as he could. Both the javelin and one of Shepard’s golf balls ended up in a small crater about 25 metres away.

After Shepard’s indulgent golf swing, David Scott focused on science in his earnest demonstration of high-school physics. He and Joe Allen, his Capcom during his surface exploration came up with the idea of dropping a hammer and feather simultaneously to show viewers that, as predicted by well established theory, both masses would fall at the same speed. Scott was worried that static electricity might ruin the experiment and had brought two feathers, one to rehearse with and one for the TV. In the event, he did not have time for the trial run and hoped it would work first time, which it did. Allen was subsequently responsible for a chapter in Apollo 15’s Preliminary Science Report that summarised the scientific results of the mission. Among the more obscure descriptions of the various experiments and investigations was this paragraph, written with perhaps a hint of tongue-in-cheek humour:

"During the final minutes of the third extravehicular activity, a short

demonstration experiment was conducted. A heavy object (a 1.32-kg aluminum

geological hammer) and a light object (a 0.03-kg falcon feather) were released

simultaneously from approximately the same height (approximately 1.6 m) and were allowed to fall to the surface. Within the accuracy of the simultaneous release, the objects were observed to undergo the same acceleration and strike the lunar surface simultaneously, which was a result predicted by well – established theory, hut a result nonetheless reassuring considering both the number of viewers that witnessed the experiment and the fact that the homeward journey was based critically on the validity of the particular theory being tested.’’

Flaying with gravity was the theme of John Young’s signature stunt on Apollo 16. During their first EVA, when he and Charlie Duke were working around the LM, they took time out for the almost obligatory tourist shot of each crewman saluting next to the Stars and Stripes.

‘ Iley. John, this is perfect.” said Duke gleefully, ‘with the LM and the rover and you and Stone Mountain. And the old flag. Come on out here and give me a salute. Big Navy salute.”

“Look at this," said Young.

lie worked his arm so the suit’s cables would permit a salute then promptly launched himself nearly half a metre off the ground. Young’s total mass was about 170 kilograms including his suit and FLSS. But on the Moon it felt more like 30 kg and with barely a twitch of his legs and feet, he jumped a second time. Duke took a photograph at just the right moment to show Young apparently floating above the lunar surface.

As they wrapped up their final EVA. Young and Duke decided to Lake lunar athletics a stage further. Using the rover to steady himself. Young began to jump, getting higher each time until he reached a height of 70 centimetres. “We were gonna do a bunch of exercises that we had made up as the Lunar Olympics to show you what a guy could do on the Moon with a back pack on, but they threw that out.” “For a 380-pound guy, that’s pretty good,” said Tony England, their Capcom. Having seen his commander go ahead with some simple athletics, Duke decided to join in with a leap of his own. "Wow!” he exclaimed as he saw how high he could rise but as he descended, he realised that he had imparted a little backwards rotation. In his slow-motion fall, and with a moment of fear and panic welling up inside, he realised that he was going to fall onto his PLSS.

“Charlie!” called Young. The FLSS was not designed to Lake a fall like this. “That ain’t any fun, is it?" said Duke sheepishly as he lay on his PLSS facing upwards.

“Thai ain’t very smart,” pointed out his commander.

“That ain’t very smart,” agreed Duke trying unsuccessfully to turn over. “Well, I’m sorry about that.”

Young saw how much dust he was going to have to brush off Duke’s suit. “Right. Now we do have some work to do.”

“Agh! How about a hand. John?”

All the crews took a childish delight at throwing things in the weak lunar gravity. They were especially impressed at how bulky but light items like sheets of plastic foil would sail off in perfect ballistic trajectories undamped by air resistance. At the end
of the final EVA on the Moon’s surface, Gene Cernan saw a chance for a really good throw. He and Jack Schmitt shared a geology hammer and there was now no further use for it. ‘‘You ready to go on up?” he asked of Schmitt.

“Well, I don’t know,” replied Schmitt who then rattled off a list of further tasks remaining.

“Well, watch this real quick.”

When Schmitt saw what Cernan was about to do with their one geology hammer, his own boyish instinct kicked in. “Oh, the poor little… Let me throw the hammer.” After all, he was the geologist, ft only seemed correct that he should get to throw the geology hammer.

Cernan acceded. “It’s all yours. You deserve it. A hammer thrower. You’re a geologist. You ought to be able to throw it.”

Schmitt took the hammer away from the spacecraft and prepared to throw it. “You ready?”

“Go ahead,” said Cernan.

“You ready for this?” repeated Schmitt, building up to the great moment. “Ready for this?”

“Yeah,” said Cernan, then added a warning. “Don’t hit the LM. Or the ALSEP.”

Schmitt brought his arm back and swung with his whole body to launch the hammer in front of the LM.

“Look at that!” cried Cernan as the hammer arced out over the land­ing site, over their footprints and their wheeltracks and over all the discarded gear they were about to leave behind, perhaps for eternity. “Look at that! Look at that!”

After a flight lasting seven sec­onds, long enough for Cernan to take a series of pictures of its coast, it landed halfway to the ALSEP site in a plume of dust, where it still lies. “Beautiful,” said Schmitt. “Looked like it was going a million miles,” said Cernan, “but it really didn’t.”

“Didn’t it?