The First True Spaceship

The Apollo Lunar Module wasn’t pretty. But it got the job done.

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In November 1969, Apollo 12 astronaut Dick Gordon took this photo of the Lunar Module Intrepid just after it separated from his Command Module. NASA

The commander of the Challenger was in the zone, which was remarkable, considering his predicament. After all, he was piloting from a standing position. He was only 44 inches away from his crewmate but forced to speak to him through an intercom. And finally, he was peering through a bubble of Lexan, a pane of Chemcor structural glass, a sheet of Vycor meteorite-stopping glass, and around a hundred layers of infrared, thermal, and anti-fog coatings at a vista no other human had ever seen.

There, through Apollo 17 commander Gene Cernan’s small triangular window, the virginal, rolling, cratered Valley of Taurus-Littrow was unfolding before his eyes. But for Cernan and lunar module pilot Harrison Schmitt, the mountains, craters, and massifs were more than a remarkable panorama; they were signposts pointing the way to a landing zone that NASA scientists had selected on the southeastern shore of the moon’s Sea of Serenity.

“There it is, Houston!” Cernan’s voice crackled over NASA’s communications loop. “There’s Camelot Crater. Wow! Right on target.”

Two hundred and fifty thousand miles away from the evolving final mission of Project Apollo, the men and women of Grumman Aerospace listened intently as the two astronauts put the lunar module through its paces. To them, the crew sounded like a well-oiled machine, and perhaps more importantly, the machine the crew was flying was matching the astronauts beat for beat. The Apollo lunar module was a Grumman design, and Apollo 17 was to be the company’s extraterrestrial swan song. But while the landing of 17 would be a crowning achievement for all “Grummies,” as NASA employees sometimes referred to them, for two smaller groups of Grumman employees it was the opportunity to settle a bet.

“The question was: Would anybody ever let the autopilot actually land the vehicle?” says former Grumman test pilot Tom Gwynne. “The [Grumman] pilots had bet a case of champagne with the engineers that nobody would actually let the autopilot land the lunar module. The engineering perspective was: The digital autopilot can do the best job, so why wouldn’t you? And the pilot perspective was: You have got one shot at it; what are you going to tell your grandchildren—that you let the autopilot land you on the moon?”

With 300 feet to go, the Challenger’s digital autopilot was still engaged and the engineers appeared to be winning the bet. It was December 11, 1972, a decade, a month, and four days since a fledgling NASA had placed a wager of its own. NASA had bet that a Long Island-based company known mostly for building capable but stout and somewhat unsightly aircraft for the U.S. Navy could build humanity’s first true spacecraft. (Such vehicles as NASA’s Mercury space capsule and the Soviet Vostok also flew in the vacuum of space, but unlike the LM, they were designed to meet the aerodynamic requirements of flying through Earth’s atmosphere during reentry.) “We got the contract in November of 1962,” says Thomas J. Kelly, Grumman’s chief engineer on the lunar module. “We had never built a manned spacecraft before. Nobody was an expert in those days, and they asked us to build a vehicle to land a man on the moon.”

NASA asked for a Lunar Excursion Module. “Then they changed the name,” says Kelly. “Somebody at NASA decided ‘excursion’ made it sound too flaky, so they changed the name to just plain old ‘lunar module.’ It was the easiest modification we made during the entire program.”

Changes came fast and furious in the early days of the LM. The original Grumman design called for a 22,000-pound, two-stage vehicle: a descent stage with five fixed landing gear that would carry the astronauts to the moon and an ascent stage that would power them back into lunar orbit. As far as piloting, designers rationalized that flying to the moon should be as much like a helicopter ride as possible, so they strapped the astronauts into two 75-pound seats and had them looking for acceptable landing spots out four huge, helicopter-like bubble windows.

But even the most junior aeronautical engineer back in 1962 knew that windows cause thermal, structural, and weight problems. The windows would have to get smaller. Still, there was no getting around the requirement that astronauts had to see where they were going. Then some bright bulb at NASA or Grumman (nobody recalls exactly who) realized that just because pilots always flew sitting down in the atmosphere did not mean they had to fly that way outside of it. (The closer an astronaut’s face is to the window, the greater his field of view, and a standing astronaut can position his face much closer to a window than a seated astronaut can.) Studies showed the astronauts would not encounter more than one third of Earth’s gravity during the flight of the LM. The result was that the astronauts would now stand side by side at a distance of 16 inches from a pair of two-square-foot windows. The new configuration gave them a 20-times-greater field of view from one-tenth the window area.

By October 1964, after almost two years and a mountain of engineering drawings, Grumman had a good idea what its now-33,000-pound lunar lander would look like—like no flying machine anybody had ever seen before. “You have to remember that the LM was carried in the Saturn’s protective shroud and only operated in the vacuum of space,” says Kelly. “That allowed us to design it from the inside out because we had no concerns for aerodynamics at all, which resulted in the distinctive look for the LM.”

But what was for engineer Kelly a “distinctive look” was something else for the aviators who would fly it. “My first thought was that the thing was Godawful,” says Apollo 14 lunar module pilot Ed Mitchell. “Although I knew exactly why it looked the way it did, I still couldn’t help but think…yuck! I mean, I was a fighter pilot and used to aerodynamic as well as aesthetically pleasing high-performance jets, and here I am looking at this…this…thing.”

“We called it ‘the Bug,’ ” says Gene Cernan, the mission commander on Apollo 17. “And to me it looked like some gigantic monster that was gonna hop down New York City just gobbling up society.”

Looks aside, the LM was the astronaut corps’ one and only way down to the lunar surface and off. With so much at stake, Grumman’s factory in Bethpage, Long Island, became a familiar stop on many an Apollo astronaut’s weekly itinerary. Since time was the most valuable commodity in the Apollo program, NASA spared no expense in getting the astronauts to and from Bethpage. “I would sign out a T-38 [a supersonic jet trainer],” remembers Mitchell, “and fly it from Houston up to Calverton Field on the tip of Long Island. Then I’d grab a smaller jet, a T-33, and fly that down to the airport on Grumman’s site.”

By 1966, visiting astronauts found Grumman’s Plants 5, 25, and 30 overflowing with 7,500 personnel, 3,000 of them engineers who were well on their way to cranking out by hand more than 50,000 technical drawings for the LM. For each module, it took six months to go from drawing blueprints to bending metal, and another two years to test each vehicle. For astronauts, engineers, craftsmen, and technicians alike, the LM experience was long hours, tremendous pressures, and a payoff that was years down the road.

“During testing, the hours were very sporadic,” says Apollo 13 LM pilot Fred Haise. “On many occasions I’d be in the LM cabin working on a test and things would not be working smoothly. Then there would be a stop and the test engineers would decide whether to proceed. If I thought it was going to take a while, I would leave the LM and go back to a trailer we had nearby and try to take a nap. If I thought it was going to be a short delay, many times I would just lay on the floor of the LM and go to sleep. Later, I figured that over the 17 months I worked at Grumman, I probably slept 30 days’ worth in the LM.”

Challenger was orbiting the moon at a speed of 4,563 mph and an altitude of 40,700 feet, and things were about to get a lot more interesting. Cernan launched computer program P-63 to begin the Powered Descent Initiation. When P-63 flashed on the LM’s little green electro-luminescent computer display and the main engine kicked in, an LM crew knew they were approximately 260 miles and 12 minutes of computer crunching away from the moon’s surface.

In the moment prior to PDI, Challenger was on its back, windows pointed heavenward, its big and—for the moment—silent main engine pointed in the direction of orbital motion, the direction Challenger was headed.

Inside the lunar module, the astronauts were in full spacesuits, including helmets and gloves. They were surrounded by 12 instrument panels on which were arranged 158 switches, 16 variable controls, four hand controllers, two computer keyboards, and a mosaic of changing and fixed numeric displays. To work efficiently in zero gravity, they were restrained from floating around the LM cabin by elastic cords that were fastened to the floor of the LM at one end and hooked onto the sides of each spacesuit at waist level at the other. Of course, they couldn’t go far anyway in the LM’s crew compartment, which measured 92 inches in diameter by 42 inches deep.

Along with the two astronauts inside the LM, there was a third “crewman.” Dubbed “Pings” by the astronauts, the Primary Guidance and Navigation Section (PGNS) was the first digital autopilot in a manned spacecraft. With PGNS driving, the astronauts were relieved of some of the more monotonous and labor-intensive flying duties and thus were free to monitor the instruments and observe the moonscape. They could, however, take over manual control when expedient or necessary.

At a given moment, planned months in advance and 250,000 miles away by a roomful of men with thick-rimmed glasses and slide rules, PGNS opened an array of valves, allowing two of the most corrosive chemicals on earth, unsymmetrical dimethylhydrazine and nitrogen tetroxide, to rush through fuel and oxidizer lines with the full intent of obliterating each other on contact. The controlled annihilation took place in the descent engine’s combustion chamber.

For the first 26 seconds, the engine fired at only 1,280 pounds, 10 percent of potential thrust. With commander and LM pilot looking on like mother hens, PGNS checked engine performance and gimballed the descent engine to fire through the ship’s center of gravity. Then the first rocket engine that could be throttled in space kicked into high gear.

“At first you don’t feel much of anything,” says Cernan. “But 26 seconds later, when the descent engine went to full throttle, it was like a booming growl and the vibration felt like big wheels churning beneath your feet.”

The LM began to bleed off the forward momentum that had kept it in lunar orbit. Within seconds the astronauts were below orbital velocity. If there was an emergency now, if the PGNS went crazy or the descent engine failed, their crewmate in the Apollo command module could not descend to save them, as he could have if they were orbiting above an altitude of 40,000 feet. The LM crew would now have to work it out for themselves.

Back in Houston, controllers monitored the descent. Had tracking data indicated that the LM was veering away from the planned landing site, they would have transmitted new coordinates for the astronauts to load into the computer. Even without Houston’s input, PGNS could compare the LM’s position to the mission flight plan programmed into its memory and issue corrective throttle and steering commands if needed.

During P-63, the majority of the rocket firing came from the descent engine. But with sloshing fuel making up more than half the entire weight of the LM, things had a tendency to get out of sorts. To fine-tune the LM’s attitude, PGNS called upon 16 small 100-pound-thrust motors mounted on the ascent stage in clusters of four. Called the Reaction Control System, or RCS, the little thrusters, when used in various combinations, rotated the LM about any axis and performed small translational (left-right/up-down/forward-aft) adjustments in any direction. When the RCS fired, the astronauts couldn’t miss it. “The skin of the LM was so thin,” says Apollo 10 commander Tom Stafford, “and the thrusters were right there in front of you. If you want to simulate flying a lunar module, take a washtub, put it over your head, and have a kid bang on it with a hammer.”

While the RCS was hammering away at the LM and its occupants, the LM’s landing radar was calling out to the moon. Four minutes and 55 seconds into the PDI burn, the moon answered. Microwave beams pulsing out of the Challenger’s landing radar provided the first direct contact between Apollo 17 and the lunar surface. With no appreciable atmosphere, LM crews could not rely on air pressure readings to provide altitude and airspeed information. Landing radar was so vital that NASA issued a mission rule: If you don’t get radar lock-on by 10,000 feet, abort. The LM astronauts would have aborted by separating from the descent stage, firing the ascent stage engine, and climbing to an orbit in which they would be able to dock with the command module.

Five of the six Apollo moon landing missions did not have a problem getting good radar data at an altitude of over 35,000 feet. But on Apollo 14, the radar had not yet kicked on and mission commander Alan Shepard was not happy. “They called up and said, ‘Your landing radar is not working,’ ” said Shepard in a 1998 interview. “We said, ‘Thank you very much, we’re aware of that.’ And then a little bit further on they said, ‘You know what the ground rule is, if you’re at [10,000] feet.’ Well, yeah, we knew that. Finally, some bright young man [in mission control] said, ‘Hey, your landing radar is working, but it’s locked to infinity. Have them pull the switch, reset it, and see if it works.’ So we pulled the circuit breaker, put it back in, and sure enough the landing radar came on.”

If there was no abort, the astronauts were ready for the approach phase, which was handled by computer program P-64 and initiated at an altitude of 7,515 feet above the moon’s surface. Traveling at a horizontal velocity of 506 feet per second and a vertical velocity of 145 feet per second, the astronauts were now ready to take their first real gander at their landing site while continuing to reduce forward and vertical velocities to near zero. They had to quickly locate important landmarks like large distinctive craters, specific mountain ranges, and rilles—cracks in the moon’s crust.

On Apollo 15, after astronauts David Scott and Jim Irwin began P-64, they found themselves heading for the wrong location. “As we pitched over and I looked out, there were very few shadows as far as craters go,” said Scott in a 1971 crew debriefing. “I measured my east-west displacement by my relative motion to the rille, and I could see we were in fairly good shape, relative to the rille, but we were south.”

Landing in the correct location came in a close second to landing safely at all. If a moon crew was forced to land an appreciable distance from its intended target, a mission’s entire scientific objective could be compromised. The mission that ended up farthest from the target was Apollo 11, at a whopping 4.2 miles. But on that mission, which was the first moon landing, planting the flag and grabbing any moonrock were plenty good enough. On every subsequent Apollo mission, however, the landing point made all the difference.

If an LM commander was not happy with his spacecraft’s destination, he could change the LM’s trajectory by working a three-axis, pistol-grip controller in his right hand called the Attitude Controller Assembly. Like many controls in the LM, the controller assembly had more than one function. In orbit as well as closer to the moon’s surface, the astronaut could change the LM’s attitude in pitch, roll, and yaw with the controller. But during the approach phase, an astronaut could click the same assembly up, down, left, or right, incrementally changing the spacecraft flight path one degree laterally, up-range or down-range. The astronauts called it “redesignation.”

“I redesignated immediately four clicks to the right,” stated Scott. “And then shortly thereafter, after [Irwin] called me again with the numbers, I redesignated two more right and three up-range.”

Scott ended up making a record 18 redesignations, which collectively moved the LM’s landing 1,110 feet uprange and 1,341 feet north. When he landed, they were all of 2,000 feet from their intended touchdown spot, well within mission parameters.

The reason the LM pilot called out flight information for his commander was that the moon landings occurred before head-up displays had been invented. So on Apollo 17, one of Schmitt’s numerous jobs was to act as a human head-up display, feeding Cernan the rate of descent and altitude calls.

Schmitt: “Thirty-one feet per second, going down through 500. Twenty-five feet per second through 400. That’s a little high, Geno.”

Cernan: “Okay.”

Within seconds Challenger reached “low gate,” the point for making a visual assessment of the landing site to select either automatic or manual control. If the road looked clear, if the LM’s auto-targeting would make a safe landing, would Cernan let it do its job? Prior to Apollo 13, Jim Lovell asserted that if PGNS was heading for an acceptable landing spot, he would allow it to land the LM. But that was four missions and one abort ago. This was Apollo 17. The final mission. Back on Earth, Grumman’s engineers were minutes away from a case of the good stuff.

Schmitt: “Three hundred feet, 15 feet per second.”

Cernan: “Okay, I’ve got P-66.”

With those four words, the last commander of the last Apollo moon mission took over manual control of the landing of the lunar module. (P-66 was the computer program that would allow Cernan to work the controls all the way down to the lunar surface.)

“It is not that you didn’t trust it,” recalls Cernan. “But you are only coming this way one time. And I’m sure not going to let some damn computer land it. The computer can give me all this information and I decide whether it’s useful or not, but I’m the guy who is going to land it.”

P-66 was about more than personal pride, however. The reconnaissance photographs that mission planners used to select the lunar landing sites had a resolution of 20 meters (65 feet), so a 19-meter boulder or crater that could easily tip the LM over may not have shown up. Even an appreciable slope could make unloading equipment next to impossible, and a one-meter-wide rock, if the LM managed to land on it just right, could overpressure the descent engine bell and cause one healthy explosion. So when Cernan looked out his window and saw that Challenger was headed for a boulder field, he did what Armstrong, Conrad, Shepard, Scott, and Young did before him. He flew his LM out of harm’s way.

To fly the LM, Apollo commanders found, was not an unnatural act. It was comparable to flying the helicopters that they trained in (both craft could hover; a helicopter would use the thrust generated by its rotor, whereas the LM would use the thrust of its descent engine). The commanders also spent hour upon hour in simulators. But early on, NASA knew that the simulators lacked fidelity in reproducing the final stages of landing, and real LMs were fragile and way too expensive to crater the home planet with, so they turned to the Lunar Landing Training Vehicle—the “Flying Bedstead.”

“Of all the aircraft I’ve flown over the years,” said Pete Conrad in a 1996 interview, “that was the one that scared the crap out of me.”

The training vehicle was a jet- and rocket-propelled craft that looked like it was designed by a hyperactive kid with the world’s biggest erector set. During lunar landing training, the astronaut would fly the LLTV to an altitude of several hundred feet, then switch to Lunar Simulation Mode. With five-sixths of the vehicle’s weight neutralized by its jet engine, the astronaut controlled the descent by throttling two rocket engines, and he adjusted attitude by working 16 control thrusters. While the craft quickly earned a reputation as a valuable training tool, it was also regarded as squirrelly and unforgiving. Despite the fact that three out of five Flying Bedsteads crashed (one with Neil Armstrong at the controls), LM commanders returning from the moon continued to give it a thumbs-up. “The LLTV is an excellent training vehicle for the final phases,” said Conrad. “I think it’s almost essential. I feel it really gave me the confidence that I needed.”

With 300 feet to go, Apollo 17’s Cernan needed all the confidence he could get since he was getting his first taste of real stick time after 250,000 miles. “You mostly controlled by changing your attitude,” says Cernan. “If I wanted to go a little left, I just roll to the left and the thrust vector would force me left. But now you’re still drifting left, so you’ve got to take it out. So you roll right. And so your attitude, which would change the direction of thrust from the descent engine, is what pretty much controlled your movements.”

The unique gravity and atmospheric conditions near the moon’s surface made attitude changes a dramatic event. “In a helicopter on Earth you can pull the nose up four or five degrees to stop forward motion,” says John Young, the commander on Apollo 16. “In the lunar module you’d pull it up 30 degrees.”

While Cernan was in charge of Challenger’s attitude and therefore its left/right, front/back velocity, he had to negotiate with PGNS to control the throttle. When P-66 kicked in, all Apollo commanders allowed PGNS to adjust the engine’s thrust to maintain a constant rate of descent. If the astronaut wanted to hasten his rate of descent, he could change it in one-foot-per-minute increments by clicking downward on the T-shaped thrust/translational controller in his left hand. Conversely, if he wanted to slow his descent, he would click up.

So on Apollo 17, Cernan pitched and rolled and flattened and steepened Challenger’s trajectory, and soon the boulders he could see through his window were well away from the reasonably level landing site ahead of him. But nothing was assured until touchdown. “Below the 200-foot level, you are in the dead man’s curve,” says Cernan. “Past that point, if the descent engine quit burning for any reason, you would fall to the surface and crash before you could manually abort.”

But Challenger’s engine kept burning as Cernan and Schmitt began their final descent.

Schmitt: “Going down at five [feet per second]. “The fuel’s good. One hundred ten feet. Stand by for some dust.”

As Challenger’s radar altimeter passed through 80 feet, both commander and pilot noticed faint tendrils of dust being kicked up by the LM’s descent engine. With no atmosphere to lift it skyward, the lunar dust silently skimmed the surface as it shot out from under Challenger in all directions.

On Challenger’s instrument panel, between the commander and the LM pilot, there was a small blue light labeled “lunar contact.” The bulb’s sole purpose was to illuminate when one of three 5.6-foot-long probes that extended below Challenger’s footpads crunched into moon and completed an electrical circuit. It was the LM pilot’s responsibility to notice when the contact light went on.

“Contact,” said Schmitt.

Cernan’s gloved right hand immediately shot out. The LM’s two most important buttons were the red abort button and the blue engine-stop button. Cernan hit the blue button. “That’s when the bottom falls out,” says Cernan. “You hit zero-G again for a second and then you hit.”

Challenger impacted the Valley of Taurus-Littrow at a leisurely three feet per second, well within the LM’s structural limit of 10 feet per second. But because Cernan and Schmitt had lived in zero gravity for four days, the impact felt like a ton of bricks.

“The light came on,” wrote Apollo 15 LM pilot Jim Irwin in his book, To Rule the Night. “I called ‘Contact!’ Dave hit the button to shut off the engine and we hit hard. It was the hardest landing I have ever been in. Everything rocked around and I thought the gear was going to fall off.”

In any LM’s life, landings are the moment of truth. “Touchdown is the most acceleration that the vehicle is going to feel,” says Schmitt. “If something is going to break, it is probably going to break at touchdown.”

Schmitt, like all LM pilots before him, was just as busy after touchdown as he was before. “There was no time for congratulations and popping of champagne corks,” says Buzz Aldrin, who flew on Apollo 11. “It was a busy time to be ready to respond because your life and the mission depends on that.” Schmitt spent the next couple of minutes analyzing everything from cabin pressure integrity to battery ampere hours remaining. Finally, after confirming that Challenger was not hemorrhaging fuel or otherwise in trouble, the commander and LM pilot took their first long look at their new digs.

Schmitt: “Oh man, look at that rock out there!”

Cernan: “Epic moment of my life.”

It has been 29 years since the voyage of Apollo 17, and who can say when we’ll go back to the moon. But when we do, rest assured there will probably be pilots who bet engineers on just how it will be done.

Former Grumman test pilot Tom Gwynne has some advice for future bettors: Get it in writing. “We won the bet,” says Gwynne. “Although I’d have to say it was a hollow victory. I never did get a sip of champagne.”

A Daring Dress Rehearsal

The lunar module was the Apollo program’s big unknown. Data from the [Apollo 5] unmanned flight looked good, but the LM lacked the assurance that comes from having sharp-eyed astronauts living aboard it in space—flying, probing, noticing every detail of its in-flight performance. The LM would get its second chance to fly in space with the March 3, 1969 launch of Apollo 9. It would be an ambitious 10-day mission with the goal of performing in Earth orbit the entire sequence of events required on a lunar mission, except for the actual landing.

It was our Grumman support team’s first direct experience with astronauts on a real mission, and I found it exciting that men whom I knew were up in space flying our machine. The giant three-stage Saturn V booster lifted off on schedule and performed flawlessly, placing the spacecraft into exactly the planned Earth orbital altitude. The critical maneuvers of command and service module (CSM) separation from the spacecraft/LM adapter, and rotation and docking to the LM, went perfectly. After six hours of checking out the CSM and its systems, [commander James A.] McDivitt fired the service propulsion system, and the powerful rocket engine boosted the heavily laden CSM-LM combination into a higher orbit. He sounded relieved that the dormant LM was still there after the force of the first burn. Following these operations the crew settled down for a meal and sleep. I took advantage of the quiet time to hand over my Mission Control watch to a colleague.

I was back to Mission Control early the next morning, listening to the crew puffing as they donned their spacesuits to enter the LM, which they had named Spider. The crew channel went dead. We did not learn until the postflight briefings that [lunar module pilot Russell L.] Schweickart had vomited. After some delay he entered the LM and flipped dozens of switches to activate its systems. He commented that the LM was quite noisy, particularly its environmental control system. McDivitt joined him, and after they unpacked the television camera in the LM cabin we watched them on worldwide TV. Our friend McDivitt promptly embarrassed us by pointing out to the world a washer and other bits of manufacturing debris floating through the cabin under zero gravity. It was a chastisement we deserved, and it motivated us to still more stringent efforts to clean the cabin and all closed compartments of the LM during assembly and test.

McDivitt and Schweickart extended the LM’s landing gear, which locked smartly into place upon command. They checked out the LM’s systems and fired the LM descent engine for more than six minutes at full thrust while in the docked condition, simulating much of the powered descent burn that would be required to bring the LM down from lunar orbit for landing. When McDivitt and Schweickart rejoined Dave Scott in the command module, they felt that their LM would be up to the challenges ahead.

The fifth day in orbit was the crucial part of the mission for the LM—the demonstration of the LM’s flight maneuverability, and its ability to rendezvous in orbit from a far distance. My colleagues and I scrutinized the instrumentation readouts on our consoles carefully as the crew reactivated Spider’s systems. Hundreds of pressure, temperature, voltage, current, and other measurements located in all the systems were sampled several times a second, giving us detailed real-time information on the LM’s health and performance. With all systems activated, Spider looked good to the crew, to the flight controllers, and to me. Over the net came Flight Director Gene Kranz’s crisp voice: “Apollo 9, you’re go for LM sep” (lunar module separation).

No longer joined at the head to the command module Gumdrop, Spider cavorted briefly, testing her reaction control system, and then pirouetted slowly before Gumdrop’s windows, preening for Dave Scott’s inspection. He pronounced her beautiful. After 45 minutes of maneuvering within three miles of Gumdrop, McDivitt fired the descent engine, putting more distance between the two spaceraft. Subsequent firings increased the separation distance to over 110 miles, where the pilots could no longer see each other’s spacecraft. Spider’s crew then separated the ascent from the descent stage while igniting the ascent engine in an orbital simulation of lunar liftoff, and successfully completed orbital rendezvous with Gumdrop.

Spider performed so consistently well that I never felt any apprehension as I watched each critical event of the mission click off like clockwork. I could hardly believe that this agile machine, dancing so gracefully through space, was the same crotchety beast with the broken wires and structural cracks that had given us fits for over two years of ground testing. Was our LM design and construction really good after all, or were we just lucky? I was not sure, but thought it was some of both.

—from Moon Lander: How We Developed the Apollo Lunar Module, Thomas J. Kelly, © Smithsonian Institution Press, 2001.

The Soviet Lunar Module

They were the first to fly a satellite, a man, and a woman into space. So in the early 1960s most were betting that the Soviets would also be the first to land a man on the moon. That man was supposed to be Voskhod-2 spacewalker Alexi Leonov. His machine was the lonniy korabl, or lunar cabin.

Due to the payload limitations of the N-1, the Soviet moon launcher, Leonov’s lunar cabin weighed in at only 12,257 pounds, one-third the weight of the Apollo lunar module. With the scales of rocket science already tipping against them, the Russians were forced to delete many cosmonaut-friendly features from the LK, like a docking tunnel between the Soyuz mothership and the LK lander, separate descent and ascent stages, and one other thing—a second cosmonaut.

That’s right, after flying into lunar orbit with a comrade, Leonov was to spacewalk from the Soyuz to the LK, power up and pressurize the cabin, and fly the spacecraft on to the moon all by his lonesome.

And even in the out-of-this-world world of lunar landings, the ride from lunar orbit to the surface promised to be exceptional. After separation from the Soyuz, the LK’s computer would fire a booster stage that would plunge the LK like a cannonball toward the moon. At 4,921 feet the computer would jettison the booster and fire up the LK’s throttleable main engine. “It was a pretty gutsy way to do things,” says Apollo 11 pilot Buzz Aldrin. “But there is a lot of merit to it also. The handling characteristics of the spacecraft would be much better because you have a lighter-weight vehicle.”

Improved handling or not, peering through the circular landing window, and with the clock ticking on his extremely limited fuel supply, Leonov would certainly have had his hands full. “When I saw the moon’s surface on the screen,” says Leonov, “I would have only three seconds of hover time to decide where to land. Then I had to proceed with the landing. Difficult, but after many training sessions it was enough. It could be done.”

If Leonov had managed to land the LK safely, his stay on the surface would have been measured in mere hours: just enough time to plant the hammer and sickle, deploy an extremely limited array of scientific instruments, and grab some rocks. Then the Hero of the Soviet Union would have fired up the very same engine that landed him on the surface and rocketed into orbit to join up with the Soyuz mothership.

The LK was tested unmanned in Earth orbit in 1970 and 1971. But due to ongoing problems with the N-1 launcher (they tended to explode) and lack of political payoff (the U.S. had already won the moon race), the remaining LKs were relegated to Russian museums and the program to the roll call of also-rans in space history.

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