Apollo 11: the eagle has landed

On 16 July 1969 Wernher von Braun prayed during the final moments of the countdown for Apollo 11. Aldrin:

“T minus ten, nine…” The voice from the firing room sounded calm. I looked to my left at Neil and then turned right to grin at Mike. “Four, three, two, one, zero, all engines running.” Amber lights blinked on the instrument panel. There was a rumble, like a freight train, far away on a summer night. “Liftoff! We have a liftoff.”

It was 9:32 am.

Instead of the sudden G forces I remembered from the Titan that launched Gemini XII, there was an unexpected wobbly sway. The blue sky outside the hatch window seemed to move slightly as the huge booster began its preprogrammed turn after clearing the tower. The rumbling grew louder, but was still distant.

All five F‑1 engines were at full thrust, devouring tons of propellant each second. Twelve seconds into the flight, the Houston Capcom, astronaut Bruce McCandless, announced that Mission Control had taken over from the firing room at the Cape. We were approaching Max Q, one minute and 20 seconds after lift‑off. It felt like we were at the top of a long swaying pole and the Saturn was searching the sky to find the right trajectory into orbit.

“You are go for staging,” Bruce called.

Neil nodded, gazing at the booster instruments on his panel. He had a tuft of hair sticking out from the front of his Snoopy cap that made him look like a little kid on a toboggan ride. “Staging and ignition,” he called. The gigantic S‑IC burnt out and dropped away toward the ocean, 45 miles below us.

Oddly enough the S‑II’s five cryogenic engines made very little noise, and the Gs built gently. Three minutes into the flight, the escape tower automatically blasted free, dragging the boost protection cover with it.

Now that the cover was gone, we could look out and see the curved Atlantic horizon recede. Six minutes later, we could clearly make out the division between the arched blue band of Earth’s atmosphere and the black sky of space. The S‑II dropped away and the single J‑2 engine of our S‑IVB third stage burned for two and a half minutes before shutting down. A Velcro tab on the leg of my suit fluttered in the zero G. Apollo 11 was in orbit.

Above Madagascar we crossed the terminator into night. While Neil and I continued our equipment checks, Mike removed his helmet and gloves and carefully floated down to the lower equipment bay to check our navigation system by taking star fixes with the sextant. We had to be sure our linked gyroscopes – the “inertial platform” – were working well before we left Earth orbit.

Two hours and 45 minutes after lift‑off we were into our second orbit, just past orbital dawn near Hawaii. We were strapped tightly to our couches, with our gloves and helmets back on. Restarting the third‑stage cryogenic engine in space was risky. The temperature of liquid hydrogen was near absolute zero, but the engine’s plume was hot enough to melt steel. It was possible that the damn thing could explode and riddle our spacecraft with shrapnel.

The TLI burn began silently. But as the acceleration load went from zero to 1.5 Gs, our cabin began to shake. The Pacific tilted beneath us. Six minutes later, the burn stopped as abruptly as it had started, and my limbs began to rise once more in weightlessness. McCandless said the TLI burn had been excellent. We were travelling at a speed of 35,570 feet per second and were passing through 177 nautical miles above Earth. “Looks like you are well on your way now,” he added.

Next Mike had to carry out the “transposition and docking” maneuver he’d practiced hundreds of times in simulators. With the flick of a switch, Mike blew the explosive bolts and separated the CSM from the skirt holding us to the Saturn’s third stage, which contained the LM. At this point the CSM and LM were free of each other. Mike thrust ahead at slow speed and then used his hand controller to rotate us a complete 180 degrees. The big booster stage topped by the awkward‑looking LM froze in place against the Pacific backdrop. Mike didn’t hesitate at all to gawk at the view. A few moments later, he moved our conical command module until the triangular probe at its apex was nestled firmly in the doughnut‑ring drogue on the roof of the LM. We heard a reassuring clank and a whirring bump as the 12 capture latches snapped into place, forming an airtight tunnel between the two spacecraft.

We were kind of bizarre looking now with the bulletlike CSM wedged into the cement‑mixer LM. Also, the bulky white tube of the S‑WB was still firmly attached to the LM, and we couldn’t separate until we’d completed a long checklist. Finally, I was able to call, “Houston, Apollo 11, all twelve latches are locked.”

I looked out my window and could make out the cloud‑covered mouth of the Amazon. Even at this speed, there was no way to actually sense Earth receding, but if I glanced away from the window then looked back, more of the planet was revealed. The next time I stared out, I was startled to see a complete bright disk. We were 19,000 miles above Earth, our speed slowly dropping as Earth’s gravity tugged at us and the distance grew.

Flying steadily this way may have given us a nice view of Earth, but it also meant that one side of the spacecraft was constantly in sunshine, while the other was in darkness. You can’t do this for very long because in space the sun’s heat will literally broil delicate equipment and burst propellant tanks on the hot side, while on the shaded side the gear will freeze in the deep cold. We had to begin the “barbecue roll” slowly on our long axis so that we would distribute the sun’s heat evenly. Mike fired the thrusters and tilted the spacecraft, making us perpendicular to the plane of the ecliptic, that invisible disk of Earth’s orbit about the sun. Most people probably thought Apollo 11 was shooting toward the moon like a bullet, with its pointed end toward the target. But actually we were moving more like a child’s top, spinning on the nozzle of our SPS engine.

This movement meant that every two minutes Earth disappeared, then reappeared from left to right, moving from one window to another, followed by the hot searchlight of the sun. We could see the crescent moon out a couple of our windows, though the view was obscured by the LM’s many bulges. By this point we had entered the limbo of so‑called cislunar space, the void between Earth and the moon. We didn’t have any sense of moving up or down, but in fact we were climbing out of the deep gravity well of Earth. And as we coasted upward, our speed dropped. In 20‑some hours, we would be over half‑way to the moon, but moving at only a fraction of our original 25,000‑mile‑per‑hour escape velocity. A little later, when we would reach the crest of the hill and come under the moon’s gravitational influence, we’d speed up again.

After five hours in space, we removed our bulky suits, and the cabin seemed more spacious. We could curl up in any corner we chose, and each of us soon picked a favorite spot. I settled in the lower equipment bay, and Neil seemed to like the couches. Mike moved back and forth between the two areas, spending as much time at the navigation station down below as with the hundreds of spacecraft system instruments grouped around the couches.

Our first Apollo meal went better than we expected. None of us was spacesick – we’d been careful with head movements – so we were actually quite hungry for the gritty chicken salad and sweet apple sauce. The freeze‑dried shrimp cocktail tasted almost as good as the kind you get on Earth. We rehydrated food with a hot‑water gun, and it was nice to eat something with a spoon, instead of squirting it through tubes the way we’d done on Gemini.

The deep‑space tracking station at Goldstone in southern California (there were two others, one outside Madrid and another near Canberra, Australia) wanted us to test our television system. Neil was the narrator and he gave the weather report for Central and South America. I got some good shots of Mike floating from one window to another, and then he held the camera while I took the TV audience on a little tour of the navigation station below.

When this impromptu TV show was over I realized I was very tired. It had been a full day, and we needed sleep. When I curled up in my lightweight sleeping bag, I couldn’t help thinking how adaptable humans are. There we were, three air‑breathing creatures bedding down for the night in this tiny bubble of oxygen. Our spacecraft was like a miniature planet, built by humans like us. We were able to live inside it comfortably, though only an inch or two of alloy and plastic separated my face from the vacuum outside.

Somehow I still felt secure. Ventilators whirred softly and thrusters thumped at odd times. The radio was turned low; Houston would call us only in an emergency. We shaded our windows and dimmed the cabin. I hooked up my sleeping bag beneath the couch and stretched, floating in the luxury of weightlessness. It was time to rest.

When we’d finished our TV broadcast the next day, Charlie Duke, the capcom on duty, gave us some good news about the Soviet unmanned moon probe Luna 15. Three days before our mission lifted off, the Soviets launched this robot spacecraft in an attempt to beat America in returning the first sample of lunar material. But it now looked like their mission wouldn’t succeed. The Soviet probe was definitely in a lunar orbit, but it would not interfere with our flight path in any way. Charlie also told us that Pravda was calling Neil the “czar of the ship.” Mike and I had a good time with that. It was pretty funny to think of Neil, the pride of Wapakoneta, Ohio, as a czar.

At a ground elapsed time (GET) of 26 hours and 34 minutes, Mike fired the SPS engine for just under three seconds to begin our midcourse correction maneuver. Houston said the burn was “absolutely nominal” and that, so far, our flight path had been perfect. We were halfway to the moon.

After two full days into the mission we were 150,000 miles from Earth and our speed was less than 3,000 miles an hour. The moon was approximately 30 hours and 90,000 miles ahead of us.

We broke out the TV camera again. This would be our first time up into the LM, and Mission Control wanted to inspect it along with us. To give us room to pass through the connecting tunnel, Mike removed the probe and drogue assembly we’d used to dock the command module with the LM. We were immediately given a shock when we smelled the unmistakable stench of burned wiring that every astronaut dreads. But nothing seemed to be amiss and the electrical panel gave us good voltage readings for the circuits of the docking mechanism. Mike handed Neil the triangular spearpoint of the probe. This vital piece of equipment was in perfect condition.

“Mike must have done a smooth job on that docking,” Neil told Houston. “There isn’t a dent or mark on the probe.”

I floated up through the tunnel, dragging the portable TV camera with me. Because the command module and the LM were docked head to head, I expected a jolt of disorientation when up and down reversed themselves as I crossed into the LM cabin, but the transition seemed perfectly natural.

The LM flight deck was about as charming as the cab of a diesel locomotive. Weight restrictions prevented the use of paneling, so all the wiring bundles and plumbing were exposed. Everywhere I looked there were rivets and circuit breakers. The hull had been sprayed with a dull gray fire‑resistant coating. Some people had said the first moon landing would be the culmination of the Industrial Revolution; well, the lunar module certainly looked industrial enough to prove it.

But the Eagle was a featherweight locomotive. It could accelerate from zero to 3,000 miles an hour in 2 minutes during the ascent. The walls of the pressure cabin were so thin I could have jabbed a screwdriver through them without a lot of effort. Everything had been stripped down to the extreme. Even the safety covers had been removed from the circuit breakers and switches.

After lunch that day I asked Neil if he knew what he was going to say when he stepped onto the lunar surface. He took a sip of fruit juice and shook his head. “Not yet,” he said, “I’m still thinking it over.”

On our second day outbound, Apollo 11 flew into the shadow of the moon, which was now less than 40,000 miles away. From where we were the moon eclipsed the sun, but was lit from the back by a brilliant halo of refracted sunlight. There was also a milky glow of Earthshine highlighting the biggest ridges and craters. This bizarre lighting transformed the moon into a shadowy sphere that was three‑dimensional but without definition.

“The view of the moon that we’ve been having recently is really spectacular,” Neil reported. “It’s a view worth the price of the trip.”

We strapped ourselves to the couches again the next day to get ready to swing around the left‑hand edge of the moon. Hidden around the far side, we would experience loss of signal and would be out of touch with Houston for 48 minutes; that would be when Mike would punch the PROCEED button that would fire the SPS engine for lunar orbit insertion. I gazed to my right out the small window. All I saw was the corrugated, grayish‑tan moonscape. The back side of the moon was much more rugged than the face we saw from Earth. This side had been bombarded by meteors since the beginning of the solar system millions of centuries ago. Mike read off the digits from his DSKY [Display and Keyboard] screen. The burn began exactly on time. My hand settled on my chest, and the calves of my legs flexed. This had to go right. For six minutes the SPS engine burned silently, slowing the spacecraft to just over 3,600 miles per hour, the speed necessary for us to be “captured” by lunar gravity. When the engine finally stopped, we rose again, weightless against our couch straps. Mike was beaming. We had slipped over the rim of the moon’s gravity well. Tomorrow, Neil and I would board the LM and slide all the way down to the surface.

Thirty minutes later we passed around the front of the moon and our earphones crackled with the static of Houston’s radio signal.

“Apollo 11, this is Houston. How do you read?” I could hear in Bruce McCandless’s voice the strain they’d endured waiting for us. For over 40 minutes no one had known if the LOI burn had gone safely.

“Read you loud and clear, Houston,” Mike answered.

“Could you repeat your burn status report?” In my mind I could see the rows of anxious faces at the consoles in Mission Control.

Mike was grinning his famous grin. “It was like… it was like perfect.”

Before the second burn, which would circularize our lunar orbit, we had to align our navigation platform’s gyroscopes using star sightings. Mike was down at the navigation station, his face against the eyepiece, his legs floating free. He used the code numbers of the stars from our charts, but we double‑checked them with their proper names… Rigel, Altair; Fomafhaut. These exotic names had been given to the stars by the ancient Sumerians, the world’s first navigators. The names had been carried forward by the Greeks and Romans, through the Arab mariners to the Age of Exploration. When Columbus took a star sight, he too pronounced those names. Now Mike Collins, command module pilot of Apollo 11, was using them in our voyage to the moon.

The LM was equipped with a computer which was fitted with a display and keyboard (DSKY). Aldrin:

Neil and I had moved into the LM in preparation for undocking from Columbia. Mike told us to be patient while he worked through his preseparation checklist. Mike had to replace the drogue and probe carefully before sealing off the command module and separating from the LM. We were all conscious of the fragile docking mechanism. In 24 hours, we would be needing that tunnel again. When Mike finally finished we were on the far side of the moon again, in the middle of our thirteenth orbit.

Back on the moon’s near side, we contacted Houston, so that Mission Control could monitor the stream of data from the LM and CSM. The hatches were sealed; now the LM was truly the Eagle and the command module was Columbia. “How’s the czar over there?” Mike asked Neil.

Neil watched the numbers blinking on our DSKY, counting down for the separation maneuver. “Just hanging on and punching buttons,” Neil answered. We exchanged long blocks of data with Mike and with Houston. The numbers seemed endless.

Houston rewarded us with a terse, “You are go for separation, Columbia.”

Mike backed the command module away with a snapping thump. Then the moonscape seemed to rotate slowly past my window as the LM turned, until it hung above my head. “The Eagle has wings,” Neil called.

Neil and I stood almost shoulder to shoulder in our full pressure suits and bubble helmets, tethered to the deck of the LM by elastic cords. Now we were the ones who were engrossed with long checklists. But I felt a sharp urgency as I flipped each switch and tapped the data updates into the DSKY. When Mike thrust away from us in Columbia, he simply said, “Okay, Eagle, you guys take care.”

“See you later,” was all Neil replied. It sounded as if they were heading home after an easy afternoon in the simulator room.

Just before Neil and I looped around the back of the moon for the second time in the LM, Charlie Duke, who was now capcom, told us, “Eagle, Houston. You are go for DOI.”

“Descent orbit insertion” was a 29.8‑second burn of our descent engine that would drop the perilune, the lowest point in our orbit, to eight miles above the surface. If everything still looked good at that point, Houston would approve powered descent initiation (FDI). Twelve minutes later Neil and I would either be on the moon or would have aborted the landing attempt.

The LM flew backward, with our two cabin windows parallel to the gray surface of the moon. The DOI burn was so smooth that I didn’t even feel a vibration through my boots, only a slow sagging in my knees as the deceleration mounted when we throttled up from 10 percent to 100 percent thrust. Before the throttle‑up was finished, I could tell from the landing radar data that our orbit was already bending. Neil turned a page in the flight plan and grinned at me through his helmet.

The moon rolled by silently outside my window. The craters were slowly becoming more distinct as we descended. There wasn’t much to do except monitor the instruments and wait for AOS (acquisition of signal). As we got closer; the moon’s color changed from beige to bleached gray. The hissing crackle of Houston’s signal returned to our earphones. “Eagle, Houston,” Charlie Duke called through the static. “If you read, you’re go for powered descent. Over.”

Neil nodded, his tired eyes warm with anticipation. I was grinning like a kid. We were going to land on the moon.

Mission Control was quiet. The terracelike rows of consoles descended to the front rank, the “trench.” Plaques from all of NASA’s manned missions were hung along the walls. Wide data‑projection screens covering the front wall “scribed” the Eagle’s descent trajectory toward the surface of the moon.

Flight director Gene Kranz hunched over his console in the second row listening to his team’s callouts. Their acronyms had become nicknames: FIDO (flight dynamics officer) and GUIDO (guidance officer), and this shift’s capcom was Charlie Duke. Eagle was descending through 42,000 feet and had just yawed around to its pre‑programmed attitude. GUIDO, a 26‑year‑old engineer named Steve Bales sitting at the middle console in the trench, gave Kranz the intermediate “go.”

“Capcom,” Kranz told Charlie, “they are go.”

“Eagle, Houston,” Charlie Duke called. “You are go. Take it all at four minutes. You are go to continue powered descent.”

The data on the consoles showed that the LM’s pitchover was correct. But when the digits 1202 suddenly appeared on Bales’s screen, he knew the same alarm was flashing on Eagle’s DSKY.

“Twelve‑oh‑two,” I called. “Twelve‑oh‑two.”

The 12 01 and 12 02 codes were called “executive overflow,” meaning that the LM’s onboard computer was overloaded with data. We didn’t necessarily have to abort on this signal – not yet, at least. Bales saw that Eagle’s computer was recycling, so the hardware was probably still in good condition. But with the LM a quarter million miles away, dropping toward the moon’s surface, he couldn’t be 100 percent certain this wasn’t an indication that something else was wrong.

“Give us the reading on the twelve‑oh‑two program alarm,” Neil Armstrong called, his voice strained.

“GUIDO?” Kranz asked.

Bales again scanned his data, and then replied, “Go.”

Charlie Duke frowned. “We’ve got… we’re go on that alarm.”

In the back row, Bob Gilruth, Chris Kraft, George Low, and Sam Phillips stared at their consoles. Kraft was the only one who knew anything about the program alarms. A man with close‑cropped white hair sat alone at the far end of the row It was John Houbolt, the Langley mathematician who had successfully backed Lunar Orbit Rendezvous.

Eagle was approaching 4,000 feet. Gene Kranz leaned forward to speak into his microphone. He had a crewcut and wore narrow black ties that made him look like he’d successfully avoided the 1960s altogether.

“All flight controllers, coming up on go‑no go for landing,” he told his officers. “FIDO?”

“Go!”

“GUIDO,” Kranz asked, “you happy?”

Bales had to either fish or cut bait. The program alarms were popping up again, though they weren’t signaling an obvious problem with the hardware. But he just couldn’t be certain Eagle would have a good computer for ascent the next day. “Go!” he answered.

“Eagle,” Charlie Duke called, “you’re go for landing.”

Twenty seconds later, Eagle passed through 2,000 feet and another program alarm flashed.

“Twelve alarm,” Neil called. “Twelve‑oh‑one.”

“Roger,” Charlie acknowledged. “Twelve‑oh‑one alarm.”

“GUIDO?” Kranz asked. Even his voice was strained.

Deke Slayton was sitting next to Kranz, and he was almost doubled over with tension, dragging deeply on a cigarillo.

Bales looked at the data on his screen. “Go.”

“We’re go,” Charlie Duke told Eagle. “Hang tight, we’re go.”

We were just 700 feet above the surface when Charlie gave us the final “go,” just as another 1202 alarm flashed. Neil and I confirmed with each other that the landing radar was giving us good data, and he punched PROCEED into the keyboard. All these alarms had kept us from studying our landing zone. If this had been a simulation back at the Cape, we probably would have aborted. Neil finally looked away from the DSKY screen and out his triangular window. He was definitely not satisfied with the ground beneath us. We were too low to identify the landmark craters we’d studied from the Apollo 10 photographs. We just had to find a smooth place to land. The computer, however, was taking us to a boulder field surrounding a 40‑foot‑wide crater.

Neil rocked his hand controller in his fist, changing over to manual command. He slowed our descent from 20 feet per second to only nine. Then, at 300 feet, we were descending at only three and a half feet per second. As Eagle slowly dropped, we continued skimming forward.

Neil still wasn’t satisfied with the terrain. All I could do was give him the altimeter callouts and our horizontal speed. He stroked the hand controller and descent‑rate switch like a motorist fine‑tuning his cruise control. We scooted across the boulders. At two hundred feet our hover slid toward a faster descent rate.

“Eleven forward, coming down nicely,” I called, my eyes scanning the instruments. “Two hundred feet, four and a half down. Five and a half down. One sixty…” The low‑fuel light blinked on the caution‑and‑warning panel. “… quantity light.”

At 200 feet, Neil slowed the descent again. The horizon of the moon was at eye level. We were almost out of fuel.

“Sixty seconds,” Charlie warned.

The ascent engine fuel tanks were full, but completely separate from the descent engine. We had 60 seconds of fuel remaining in the descent stage before we had to land or abort. Neil searched the ground below.

“Down two and a half,” I called. The LM moved forward like a helicopter flairing out for landing. We were in the so‑called dead man’s zone. You couldn’t remain there long. If we ran out of fuel at this altitude we would crash into the surface before the ascent engine could lift us back toward orbit. “Forward. Forward. Good. Forty feet. Down two and a half. Picking up some dust. Thirty feet.” Below the LM’s gangly legs, dust that had lain undisturbed for a billion years blasted sideways in the plume of our engine.

“Thirty seconds,” Charlie announced solemnly, but still Neil slowed our rate.

The descent engine roared silently, sucking up the last of its fuel supply. I turned my eye to the ABORT STAGE button. “Drifting right,” I called watching the shadow of a footpad probe lightly touching the surface. “Contact light.” The horizon seemed to rock gently and then our altimeter stopped blinking. We were on the moon. We had about 20 seconds of fuel remaining in the descent stage. Immediately I prepared for a sudden abort, in case the landing had damaged the Eagle or the surface was not strong enough to support our weight.

“Okay, engine stop,” I told Neil, reciting from the checklist. “ACA out of detent.”

“Got it,” Neil answered, disengaging the hand control system. Both of us were still tingling with the excitement of the final moments before touchdown.

“Mode controls both auto,” I continued, aware that I was chanting the readouts. “Descent engine command override, off Engine arm, off…”

“We copy you down, Eagle,” Charlie Duke interrupted from Houston.

I stared out at the rocks and shadows of the moon. It was as stark as I’d ever imagined it. A mile away, the horizon curved into blackness.

“Houston.” Neil called, “Tranquillity Base here. The Eagle has landed.”

It was strange to be suddenly stationary. Spaceflight had always meant movement to me, but here we were rock‑solid still, as if the LM had been standing here since the beginning of time. We’d been told to expect the remaining fuel in the descent stage to slosh back and forth after we touched down, but there simply wasn’t enough reserve fuel remaining to do this. Neil had flown the landing to the very edge.

“Roger, Tranquillity,” Charlie said, “we copy you on the ground. You’ve got a bunch of guys about to turn blue. We’re breathing again. Thanks a lot.”

I reached across and shook Neil’s hand, hard. We had pulled it off. Five months and 10 days before the end of the decade, two Americans had landed on the moon.

“It looks like a collection of just every variety of shapes, angularities, granularities, every variety of rock you could find,” I told Houston. Everyone wanted to know what the moon looked like. The glaring sunrise was directly behind us like a huge searchlight. It bleached out the color; but the grays swam in from the sides of my window.

Charlie said there were “lots of smiling faces in this room, and all over the world.”

Neil grinned at me, the strain leaving his tired eyes. I smiled back. “There are two of them up here,” I told Charlie.

Mike’s voice cut in much louder and clearer than Mission Control. “And don’t forget the one in the command module.”

Charlie told Mike to speak directly to us. “Roger, Tranquillity Base,” Mike said. “It sounded great from up here. You guys did a fantastic job.”

That was a real compliment coming from a pilot as skilled as Mike Collins.

“Thank you,” Neil said. “Just keep that orbiting base ready for us up there now.”

We were supposed to do a little housekeeping in the LM, eat a meal, and then try to sleep for seven hours before getting ready to explore the surface. But whoever signed off on that plan didn’t know much psychology – or physiology, for that matter. We’d just landed on the moon and there was a lot of adrenaline still zinging through our bodies. Telling us to try to sleep before the EVA was like telling kids on Christmas morning they had to stay in bed until noon.

I decided to begin a ceremony I’d planned with Dean Woodruff, my pastor at Webster Presbyterian Church. He’d given me a tiny Communion kit that had a silver chalice and wine vial about the size of the tip of my little finger. I asked “every person listening in, whoever and wherever they may be, to pause for a moment and contemplate the events of the past few hours, and to give thanks in his or her own way.” The plastic note‑taking shelf in front of our DSKY became the altar. I read silently from Dean’s Communion service – I am the vine and you are the branches – as I poured the wine into the chalice. The wine looked like syrup as it swirled around the sides of the cup in the light gravity before it finally settled at the bottom.

Eagle’s metal body creaked. I ate the tiny Host and swallowed the wine. I gave thanks for the intelligence and spirit that had brought two young pilots to the Sea of Tranquillity.

Suiting up for the moon walk took us several hours. Our PLSS backpacks looked simple, but they were hard to put on and tricky to operate. They were truly our life‑support systems, with enough oxygen, cooling water, electrical power, and radio equipment to keep us alive on the moon and in constant contact with Houston (via a relay in the LM) for four hours. On Earth, the PLSS and spacesuit combination weighed 190 pounds, but here it was only 30. Combined with my own body weight, that brought me to a total lunar‑gravity weight of around 60 pounds.

Seven hours after we touched down on the moon, we depressurized the LM, and Neil opened the hatch. My job was to guide him as he backed out on his hands and knees onto the small porch. He worked slowly, trying not to jam his backpack on the hatch frame. When he reached the ladder attached to the forward landing leg, he moved down carefully.

The new capcom, Bruce McCandless, verified that we were doing everything correctly. Once Neil reached over and pulled a line to deploy the LM’s television camera, Bruce said, “We’re getting a picture on the TV.”

“I’m at the foot of the ladder,” Neil said, his voice slow and precise. “The LM footpads are only depressed in the surface about one or two inches.” The surface was a very fine‑grain powder. “I’m going to step off the LM now.”

From my window I watched Neil move his blue lunar overshoe from the metal dish of the footpad to the powdery gray surface.

“That’s one small step for… man, one giant leap for mankind.”

Lunar gravity was so springy that coming down the ladder was both pleasant and tricky. I took a practice run at getting back up to that high first step, and then I hopped down beside Neil.

“Isn’t that something?” Neil asked. “Magnificent sight out here.”

I turned around and looked out at a horizon that dropped steeply away in all directions. We were looking “down sun,” so there was only a black void beyond the edge of the moon. For as far as I could see, pebbles, rock fragments, and small craters covered the surface. Off to the left, I could make out the rim of a larger crater. I breathed deeply, goose flesh covering my neck and face. “Beautiful, beautiful,” I said. “Magnificent desolation.”

Stepping out of the LM’s shadow was a shock. One moment I was in total darkness, the next in the sun’s hot floodlight. From the ladder I had seen all the sunlit moonscape beyond our shadow but with no atmosphere, there was absolutely no refracted light around me. I stuck my hand out past the shadow’s edge into the sun, and it was like punching through a barrier into another dimension. I moved around the legs of the LM to check for damage.

“Looks like the secondary strut has a little thermal effect on it right here, Neil,” I said, pointing to some engine burn on the leg.

“Yeah,” Neil said, coming over beside me. “I noticed that.”

We were both in the sun again, our helmets close together. Neil leaned toward me and clapped his gloved hand on my shoulder. “Isn’t it fun?” he said.

I was grinning ear to ear, even though the gold visor hid my face. Neil and I were standing together on the moon.

As we moved about getting ready to set up our experiments, I watched the toe of my boot strike the surface. The gray dust shot out with machinelike precision, the grains landing nearly equidistant from my toe. I was fascinated by this, and for the first time felt what it was like to walk on the airless moon.

One of my tests was to jog away from the LM to see how maneuverable an astronaut was on the surface. I remembered what Isaac Newton had taught us two centuries before: mass and weight are not the same. I weighed only 60 pounds, but my mass was the same as it was on Earth. Inertia was a problem. I had to plan ahead several steps to bring myself to a stop or to turn, without falling.

But after a few jogging turns, I figured out how to move quite easily. Time was going by quickly, I realized, when Neil signaled me over to unveil the plaque. We stood beside the LM leg and Neil read the words: