LANTR LTV/LEV: A New Way to the Moon


Two versions of the LANTR LTV/LEV. On the left is one suggested for a SSTO launcher that could carry 20 tons to orbit and had a 13.5 meter payload bay. The one on the right could fit in a 9.5 meter cargo bay, at the cost of using less efficient methane for lander fuel, a smaller crew capsule, and a fiddly tank-within-a-tank to hold some of the craft’s liquid oxygen oxidizer. Public domain image composited from two separate diagrams in NASA’s Human Lunar Mission Capabilities Using SSTO, ISRU and LOX-Augmented NTR Technologies A Preliminary Assessment. Click for a larger view.

What it was: A mid-90s proposal for a lunar mission using an innovative rocket engine for the trip to the Moon and some basic lunar industry to refuel its chemically-driven lander for the trip back. It was one of the first proposals for a Moon mission to try and move away from a brute-force Apollo-style mission that was impossible to fund.

Details: The core difficulty with a Moon mission, or a mission to much of anywhere really, is that you need such massive vehicles. The Saturn V, for example, was 2950 tonnes when fueled, and was 111 meters tall. It was accordingly expensive: approximately US$700 million in 2016 dollars. Reusability was the route taken in the decades since to try and bring this down, but the Space Shuttle ended its life costing US$450 million per launch and for a considerably smaller payload being taken to orbit too.

By the early 1990s, in-situ resource utilization (ISRU) was seen as the next coming thing for making missions cheaper. This is to say, don’t haul all the mass you need up into space, take advantage of whatever mass is already there wherever you’re going. The difficulty here is that that mass is useless rock and, to a much lesser extent, water ice. The most obvious thing to do would be to refine cryogenic rocket propellants from it, as both rock and ice can be sources of oxygen and hydrogen. By the mid-90s people had been thinking for several years about how to do that, and what what would be possible once it could be done.

The most famous fruit of this effort was planning for Mars missions, partly because the vehicles for a traditional flight there would be ridiculously large even by Saturn V standards and partly because Mars’ carbon dioxide atmosphere is almost trivially easy to turn into methane (a decent rocket propellant) if you bring along some hydrogen from Earth. Less well-known is a lunar mission using ISRU which was developed at NASA’s Lewis Research Center.

In the early 1990s Lewis had been involved in the development of a nuclear rocket of an unusual type, what they called a LOX Augmented Nuclear Thermal Rocket (LANTR). A regular nuclear thermal rocket like NERVA runs on pure hydrogen, not burning anything at all and simply relying on nuclear power to heat the propellant and produce a high specific impulse. Unfortunately liquid hydrogen is very low density, and so the tank to hold it has to be large—and it doesn’t matter how light something is if you literally can’t fit it into the cargo bay of the Space Shuttle, or however else it is you’re planning on getting it into orbit.

The LANTR solved this problem by using liquid oxygen along with the hydrogen. After being heated by the reactor, the hydrogen was mixed with oxygen, which would then burn. This had the paradoxical effects of reducing the engine’s specific impulse, but also radically reducing the amount of hydrogen needed and making the necessary hydrogen tank much smaller. Liquid oxygen is seventy times denser than LH2, so its tank would be small too. The usual mix of oxygen to hydrogen is near 1:2 (as the chemical formula “H2O” would suggest), but even when mixed 5, 6 or 7:1 with the hydrogen the reduced specific impulse of the LANTR was still considerably better than you got with a conventional LOX/LH2 rocket while also being smaller than a pure-hydrogen nuclear rocket..


“Artist’s Illustration of a Self-Contained, Modular LUNOX Production Unit”, plus an astronaut apparently taking a selfie. Public domain image from A Revolutionary Lunar Space Transportation System Architecture Using Extraterrestrial LOX-Augmented NTR Propulsion. Click here for a larger view.

The leap to lunar ISRU came with the realization that oxygen was a major component of the Moon’s soil. For example, the orange soil famously (and excitedly) discovered by Jack Schmitt during Apollo 17 contained hydrated iron oxide, and was rich in oxygen and water. At Lewis, the combination of LANTR and ISRU for a Moon mission crystallized in a flurry of papers spearheaded an engineer there, Stanley Borowski, in combination with a variety of colleagues. Rather than go with an already compact Moon mission using entirely Earth-sourced oxygen, why not use the Moon’s native oxygen for oxidizer on the way back? The result would be smaller and cheaper still.

The result was a proposal to build a Moon landing ship that was embedded in some basic Lunar industry that would be set up prior to the crewed landing. The first step would be to send an automated lander with a teleoperated mining equipment to a site where ilmenite or some other oxygen-rich rock had been pinpointed from orbit. Also included would be a 35-kilowatt nuclear reactor, which would provide the heat to break down the lunar rock with the hydrogen that would be brought along too, producing water. The water in turn would be broken down to oxygen and hydrogen, the former being stored and the latter recycled to start the process again on the next batch of rock.

Once 10.5 tons of liquid oxygen had been built up (a process which would take a year), the LANTR LTV/LEV (Lunar Transfer Vehicle/Lunar Excursion Vehicle) crewed mission would begin. Here a little bit of variation appears. When first suggested in 1994 the craft was assumed to be using a Shuttle-C, a derivative of the Shuttle for cargo only, to get to orbit—the LANTR wasn’t powerful enough to lift the whole works by itself (and no-one was very keen on firing a nuclear engine at ground level in any case). The Shuttle-C was already a cancelled project, however, and by 1995 NASA had been pinning its hopes on the VentureStar or some similar SSTO. At the time the LANTR LTV/LEV was being bruited about, the size of the SSTO’s payload bay hadn’t been nailed down and while NASA had specified 20 tons to LEO it was unclear how long the cargo it carried could be, Accordingly Lewis Research Center came up with two LANTR LTV/LEV configurations, each of which would be lifted in three pieces and mated in orbit.

If the SSTO gave them 13.5 meters to work with, the result was a 58.8-ton, 26.2 meter-long craft. Compare that with roughly 140 tons and 35 meters for the Apollo LM/CSM/S-IVB that launched the Apollo astronauts to the Moon. This version of the LANTR LTV/LEV would have be entirely fueled by LOX and LH2, excepting (presumably, as none of the sources say) hydrazine for the RCS thrusters as usual. On top was a curiously inverted command module; the author could find no discussion of how that was handled when time came for re-entry, so one presumes rotatable seats for the crew.

The longest part of this variation was the joint LH2/LOX tank for the transfer vehicle, while the widest was the bulbous hydrogen tanks on the lander. Both had to go to get into the smaller 9.5-meter SSTO payload bay suggested. The lander was switched to a more-compact but less efficient fuel, liquid methane, while one of the two oxygen tanks for the LANTR was moved to inside the LH2 tank, and outfitted with a double wall that would keep the supremely cold hydrogen from solidifying the oxygen within. The resulting craft was slightly lighter at 58.5 tons and definitely shorter at 24.2 meters, but in return they had to come up with some way of shaving 700 kilograms off of the crew capsule. Both variations of the capsule were approximately the same size as the Apollo CM, though the first’s was slightly larger than the second.


The LANTR LTV/LEV mission profile. Note the direct descent and direct return. Public domain image via NASA from Human Lunar Mission Capabilities Using SSTO, ISRU and LOX-Augmented NTR Technologies A Preliminary Assessment. Click here for a larger view.

There was no LM, though, because the LEV was a direct-descent, direct-return vehicle. This did mean that if the stay on the lunar surface was to be of any length, a third mission, automated like the LOX plant, would have to be sent beforehand to give the astronauts a habitat. The LEV itself was inadequate otherwise.

What happened to make it fail: Though the mission was considerably cheaper than an Apollo-style trip to Moon—Johnson Space Center was looking at the time to spend less than US$1 billion on a Lunar return mission—not even that amount of money turned out to be available in NASA’s budget, particularly after the decisions were taken to continue with the Space Shuttle and build the International Space Station around the same time as the proposed first flight of a LANTR LTV/LEV’s, around 2001.

It also didn’t help that the craft came to an unwieldy size. It was intended to be launched on the VentureStar, and that never came to fruition. A comparable mission restricted to launch vehicles that actually existed needed one Shuttle mission and one launch of a Titan IV (which could lift longer payloads than the Shuttle could), a peculiar and expensive combination.

Something like it still could have begun as late as the about ten years ago, but then a discovery about the Moon put the final nail in its coffin. From 1994 through 2009 it became increasingly clear that the Moon had ice in some of its South Polar craters, with the case being settled by the Chandrayaan-1 probe. This changed the game for ISRU, since ice is a lot more useful raw material than lunar soil. Essentially all serious planning for a Moon mission since then has reflected this, and lunar rock has fallen by the wayside.

What was necessary for it to succeed: Much like the First Lunar Outpost, the LANTR LTV/LEV’s best bet would have been at the time the Clinton Administration was trying to decide how to help occupy the former Soviet Union’s rocket scientists so that they wouldn’t end up designing missiles for who knows what country. The decision to go for an joint space station rather than a joint lunar mission or base was a relatively easy one, given the USSR’s experience with stations, but it’s not too difficult to see the US deciding to go for the public relations spectacle of the Moon over the more staid ISS.

Otherwise the LANTR LTV/LEV is a sound concept if the promised Isp advantage holds, to the point that (by the standards of this blog) something much like it still would be worth building and flying. The primary difficulty with it in 2016 might be, oddly enough, that it’s too small. Sixty tons falls into the “between two stools” range that we discussed in the entry on the R-56, too big for something like an Ariane 5 or Delta IV Heavy, but too small for the upcoming SLS. Given that you’re going to have to use an SLS and that rocket will quickly outstrip 60 tons by a lot, why not design a spacecraft that uses up the extra payload capacity? Fans of SpaceX’s Falcon Heavy effort might want to take some notes, though.


A Revolutionary Lunar Space Transportation System Architecture Using Extraterrestrial LOX-Augmented NTR Propulsion. Stanley K. Borowski, Robert R. Corban, Donald W. Culver, Melvin J. Bulman, and Mel C. Mcilwain. 1994

Human Lunar Mission Capabilities Using SSTO, ISRU and LOX-Augmented NTR  Technologies A Preliminary Assessment. Stanley K. Borowski, 1995

High Leverage Space Transportation System Technologies for Human Exploration Missions
to the Moon and Beyond. Stanley K. Borowski and Leonard A. Dudzinski. 1996

The Early Lunar Shelter: Stay Just a Little Bit Longer

Garrett AiResearch Lunar Shelter

The Garrett Early Lunar Shelter, showing its roots in the LM Truck and, in turn, the LM that actually landed on the Moon. The tanks draped around it are hydrogen and oxygen for the fuel cells, shelter pressurization, and recharging the astronauts’ suits after EVA. Public Domain image via NASA from Early Lunar Shelter Design and Comparison Study, Volume IV. Click for a larger view.

What it was: A two-astronaut shelter/living quarters for use with the Apollo program once it had progressed to needing 30-day stays on the surface, studied in 1966-67 by Garrett AiResearch at NASA’s request. Variants for three astronauts and for a mobile version that could be hitched to a lunar rover were also examined.

Details: Certain big names show up repeatedly in conjunction with the American space program: North American Rockwell, Grumman, Boeing, Lockheed, and so on. Around the fringes, though are less familiar names such as Bendix and TRW. Another one of the latter was Garrett AiResearch, a mid-sized aerospace pioneer best known (at least as far as the space program goes) for designing and building the atmosphere controls for Mercury, Gemini, and Apollo.

In 1966, NASA commissioned Garrett to move beyond what they’d done to that point, and work on a  full-fledged, if tiny, Moon base. Dubbed the “Early Lunar Shelter” (ELS), the intention was to build it following the J-Class missions—what turned out to be Apollo 15 through 17. Having progressed from short surface stays like Apollo 11 to longer ones that had a lunar rover to work with, like Apollo 17, the next step was to be month-long stays and that required more than a single LM.

From the beginning, the Moon landings had been quite restricted in mass, as much of an LM was taken up with astronauts, the consumables they needed, and the fuel and engines needed to get them back to the CSM for the flight home to Earth. If you could forgo all of that with an automated lander, you could haul a lot more equipment to the Moon—to wit, 4.67 tonnes of it.

The fruit of this thinking was the LM/T, or Lunar Module Truck, which was for all intents and purposes a rocket-powered mule that would head to the Moon some time before its associated astronauts would start their journey in their own LM (called the LM Taxi in this context). Landing close to the LM/T, the astronauts could walk over, unload everything, and enjoy a huge quantity of equipment as compared to Aldrin and Armstrong.

There were any number of configurations for the LM/T, constrained only by the volume an LM occupied on top of a Saturn V and the limit to the mass it could safely land, but the Early Lunar Shelter was the answer to one particular question: “Suppose we devote the Truck’s volume entirely to living quarters for two astronauts and the scientific equipment they’d use. What would that be like?”

What Garrett came up with was a stubby cylinder, 8.1 feet in diameter and 16 feet long (2.5 meters by 4.9 meters) which rested on its side above the LM/T’s descent stage, looking not unlike contemporary bathyscaphes. It would be launched atop a Saturn V along with a crewed CSM, which would dock to a hatch on its upper side, then ferry it to the Moon after the usual Saturn IV-B trans-lunar injection. After reaching their destination, the CSM would disengage and return its crew to Earth, while the ELS would land automatically.

The shelter could sit on the Moon for as much as six months before its astronaut-dwellers arrived (thanks to another Saturn V/CSM combination), with a minimum seven days prior to their launch for checkout of the shelter. A SNAP-27 radiothermal generator would power the ELS until activation. Once aboard, the minimum time the astronauts would use it was assumed to be 14 days, with 50 days being the upper end of possibility. The first day days of the mission would be devoted to the astronauts activating the shelter for their use, unloading it, switching the shelter to running off fuel cells (which would also supply water) and transferring the RTG to their LM Taxi so their ride home could be deactivated but kept “alive” until it was needed at the end of the mission.

Interior layout of the Early Lunar Shelter

The interior layout of the ELS, same source as previous. One presumes the outer hatch was closed when the toilet was in use. Click for a larger view.

The interior of the shelter was to be divided into two main areas. One was a lunar EVA airlock taking up one end, the CSM hatch on top being used solely for docking with a CSM. It would have been big enough for two astronauts at the same time as well as storage of two hard space suits. The bulk of the shelter was 628 cubic feet (17.8 m3) of living space. Though about half of this would be taken up with supplies, bunks, and spacesuit storage, its shirt-sleeve environment compared well with a regular LM’s 4.5 cubic meters of habitable volume. Alternatively, as the Moon does supply gravity, the ELS can be sized another way: it would have had 68 square feet of floor space (6.3 square meters).

The arrangement of bunks/radiation refuge quarters in the ELS.

The spartan arrangement of bunks/radiation refuge quarters in the ELS. No Apollo astronaut was taller than 71 inches. Same source as previous. Click for a larger view.

The shelter was double-walled aluminum and fiberglass (the latter in the inside), with 58 mils (0.058 inches, or 0.15 cm) between them for meteoroid protection—the usual tactic, as invented by Fred Whipple. The other major danger entertained was radiation, and the aluminum walls couldn’t be made thick enough to sustain 500 rads (a hypothetical solar flare) without weight close to a half ton more than was otherwise necessary. Accordingly the study suggested putting the necessarily numerous  PLSS recharging canisters (for the life-support backpack worn while on the surface) stored in water filled sleeves around the bunk area located at the opposite end from the airlock. Altogether, they, the walls, and the bunk material made an acceptable, if awfully cramped, radiation refuge for everyone on-board.

One final, intriguing safety touch was the dual-purpose boom attached near the airlock. While primarily intended for unloading instruments or a rover, it would also have been used to get an incapacitated astronaut up next to the entrance to the shelter.

Arranged around and behind the shelter were four tanks: one compressed gaseous oxygen, one liquid oxygen, and two liquid hydrogen. These weren’t intended for use with the Truck’s landing engine—it had its own tankage—but rather for use by the astronauts and the fuel cells (and so, accordingly, their water). Garrett pinpointed the storage of LOX and LH2 for up to six months before the astronauts arrived as the main technical challenge facing the ELS.

Another issue was what atmosphere they would breathe: pure oxygen at 5.0 psia, or nitrogen/oxygen mix comparable to Earth. The former was desirable for mass reasons, and to keep the ELS as close in technology to the rest of the Apollo program as possible, but Garrett were concerned that there were no medical studies of a pure oxygen atmosphere for a long period of time; the 30-day maximum they note was apparently just an educated guess. They ended up punting the problem down the road as essentially an issue of how much they could keep the ELS from leaking; if that could be minimized, the problem was moot. Safety concerns weren’t mentioned at all, and in fact the final filing of Garrett’s study was on February 8th, 1967, not even two weeks after the Apollo 1 fire. After that the CSM would switch to a oxy-nitrogen atmosphere for launch, though the LM would stay with the low-pressure pure oxygen.

Mobile ELS variant, hitched to a notional rover.

The Mobile ELS variant, hitched to a notional rover. Same source as previous. Click for a larger view.

As well as being a shelter, the ELS would have been a miniature scientific outpost. It would be equipped with a drill capable of getting 100 feet down into the Moon’s crust, carry explosive charges for seismic readings, and had three remote instrument stations that would be deployed far from the landing site thanks to the extended EVA capability the shelter would provide. All told, the shelter would come with 3470 pounds (1.57 tonnes) of science gear, while the shelter itself was a remarkably light 985 pounds (447 kg). Add in the expendables and altogether it could be successfully landed on the Moon by the LM/T with a mere pound and a half to spare. Let it not be said that they didn’t squeeze all the juice out of this one.

If the project had gone ahead, Garrett anticipated that the ELS would be operational in 1972. The study is silent on cost, apparently because the construction work was to be handed off to Grumman, and so it was their problem.

What happened to make it fail: It got caught up in the rapid ramping down of the Apollo program that started in 1968, not least the fact that Saturn V production was shut down and the rockets they had were all they were going to get.

By scrimping and saving (and cutting a couple of Moon landings) NASA managed to save Skylab, and eventually the detente-driven Apollo-Soyuz Test Project, but that was it. As any mission involving the Early Lunar Shelter was going to require two Saturn V launches it was an obvious target for a cut, taking up as it would two slots that could be used by two different, separate Moon missions. It was one of the first things to go, and did not make it out of 1968.

What was necessary for it to succeed: It’s interesting to compare the Early Lunar Shelter to the other Moon bases we’ve examined so far, Barmingrad and Project Horizon. Both were hugely ambitious and nowhere near happening in reality, while for this project the key word was early. A lot of people tend to conflate Moon bases with lunar colonies, or at least the next rank down of permanently inhabiting the Moon even if the personnel are swapped out periodically. What NASA put its finger on was that we’re not likely to make that big a leap all in one go. The first lunar bases are probably going to be temporary, just like the first space stations were before we worked our way up to Mir and the ISS.

On that basis it’s easy to get the ELS to fly, as it was a big part of the logical next step in lunar exploration (ignoring the elephant in the room that was automated exploration, mind you). With probably no more than some minor redesigning there could have been one on the Moon just a few years after when Garrett AiResearch pictured it: 1972.

As ugly as the post-1969 picture was for NASA’s funding, it’s not too much of stretch to see the three or four more necessary missions past Apollo 17 making it through the budget grinder and “Apollo ELS” flying sometime around late 1974 or early 1975. It’s a lot likelier than much of what NASA proposed post-Apollo 11, at least, if only because one mission like that would be as much or more of a punctuation mark at the end of the program as any other mission bar Apollo 11 itself.


Early Lunar Shelter Design and Comparison Study, Volume I and Volume IV, W.L. Burriss, N.E. Wood, and M.L. Hamilton. Garrett AiResearch. Los Angeles, California. 1967.

FLO: The First Lunar Outpost (Space Exploration Initiative, Part I)

FLO Base Lander

One of two landers for the First Lunar Outpost, this an unmanned one with an adapted Space Station module on top for use as a place to live during the mission. The astronauts would arrive at roughly the same time aboard a manned lander. This picture is somewhat incorrect in that the real lander would have had two large solar panels stretching to the right and left. Public domain image from NASA.

What is was: A 1992 benchmark mission for NASA to return to the Moon, using expendable launchers and a direct descent lander, and build a small periodically-inhabited lunar base on the Mare Smythii.

Details: Early during the presidency of George H. W. Bush, the White House directed NASA via Vice-President Dan Quayle to come up with a plan to go to Mars—a goal announced to the public as the Space Exploration Initiative (SEI). To say that NASA botched this opportunity is to put it mildly.

Their (admittedly non-mandatory) orders were that NASA should come up with a plan that could get to Mars relatively cheaply, probably using technology that had developed since the end of Apollo. Instead they put forward an obvious relative of von Braun’s 1969 Mars Expedition, ditching the nuclear rockets but otherwise following the path of building a big space station, a permanent Moon base, and then finally moving on to Mars. The total cost of the program was estimated to be about US$540 billion over about thirty years—or, to put it another way, a rough doubling of NASA’s annual budget through the next several presidential administrations. This was political suicide and the whole thing collapsed in acrimony almost the moment it was put forward. Richard Truly’s career as NASA administrator came to an end in large part because of the fiasco and he was replaced by Dan Goldin in 1992.

Goldin’s mantra for NASA was famously “faster, better, cheaper” and he arranged for another study that would attempt to recover the manned lunar exploration part of the SEI. It was explicitly to be based on new ideas from the so-called Stafford Report (properly known as America at the Threshold: Report of the Synthesis Group on America’s Space Exploration Initiative) from the previous year. Out of this study grew the First Lunar Outpost (FLO) proposal.

Comet rocket for FLO

An artist’s rendition of the proposed HLV for the mission, referred to informally as Comet. Public Domain image from NASA.

The first step to the outpost was literally getting there. The initial SEI plan had foundered in part because of its allegiance to the Space Shuttle which, as it could lift only 25 tonnes to LEO, meant that NASA needed to build their Moon craft in Earth orbit; that in turn required a space station. FLO was based on a return to an expendable launch vehicle, and it would have been a monster: the core of the launcher would either be an all-new rocket or a stretched version of the Saturn V (to the extent that that program could be revived 20 years after its end); either would have been flanked with two boosters. Its resulting payload to LEO was to have been in the vicinity of 200 tonnes. Contrast that with the Saturn V at 118 tonnes, or 88 tonnes for the Energia.

This massive increase in capability was to be used in two ways: the Moon craft would not have to reconfigure itself in Earth orbit like the Apollo arrangement did, and it would land directly at its destination on the Moon rather than sending down a landing craft followed by a lunar orbit rendezvous before returning to Earth. As well as making the missions safer by allowing more ways to abort and opening up more of the lunar surface for exploration, this simplicity was believed to be the route to a cheaper mission despite the upfront cost of the rocket that launched it.


The FLO spacecraft on top of its TLI stage in Earth orbit. Public domain image from NASA.

Nuclear thermal engines were studied for the trans-lunar injection stage of the FLO spaceship, but it was assumed that it would probably use a J-2S LOX/LH2 engine—essentially the same as was used by the Apollo S-IVB injection stage, though slightly upgraded to use a de Laval nozzle. The lander itself would have used four RL-10s, repurposed from the tried-and-true Centaur.  Again, these choices were made with an eye to saving money by using what the American aerospace industry already had to offer.

The direct-descent/direct-return profile of the actual landing forced the lander to be quite different, though. Admittedly a scaled-up version of the Apollo CM was perched on top of it, where it would carry four astronauts in the relative comfort of 11.3 cubic meters—somewhat larger than the old CM and LM taken together. Below that, though, was a much bigger spacecraft.

It would have packed no less than ten propellant tanks, four smaller ones in an upper tier for the ascent stage, and six larger ones underneath for the lander itself. Sitting on a relatively robust landing truss and four very long legs the whole arrangement would have been 56.7 tonnes with propellant, which is more than four times the mass of the Apollo LM. It would have towered 14.1 meters above the lunar surface, and been 18.8 meters from landing-leg foot to landing-leg foot.

Another big change from the Apollo program was actually a return to what had been planned for the original Moon landings post-Apollo 20. A second, unmanned lander would have been sent prior to the manned one and landed within an easy Moon rover drive, no more than two kilometers. Its entire ascent stage would be swapped out and replaced with a 35-tonne habitation module made in the manner of a Space Station Freedom module with as few changes as possible—again as a nod towards cost.


A sketch of the interior of the FLO habitation module on top of the unmanned lander Note the solar panels. Public domain image from NASA.

This module would have been the actual base. The crew of the manned mission launched in tandem with it would live there for 45 days, exploring the region within 10 kilometers using the aforementioned rover driven by astronauts, and up to 100 kilometers driving it by remote control from the habitat. The explorers would then return home to Earth but the base would not be closed up permanently. Powered by two solar arrays that brought the width of the base craft to just over 41 meters, the intention was that further groups of astronauts could be landed nearby as often as every six months and would find themselves with usable living quarters right away.


Leaving the Moon in the Ascent/TEI stage, leaving behind the landing stage. Public domain image from NASA.

Once the lunar surface mission was over, the astronauts would return to their original landing craft. Its central stack would ignite a hypergolic N202/MMH engine (hydrogen being too tricky to hold on to for 45 days on the lunar surface) and head directly for home. The final twist on the Apollo mission design would have seen the FLO capsule land on dry land, rather than splash down into the ocean.

By sticking as much as possible to technology they already had, or at the very least were already developing, the cost of the project to the end of the first landing mission was estimated at US$25 billion, with the unmanned base touching down around 2000 and the manned follow-up soon after. Just over half of this money would be for the development of the launcher and building three rockets. Even making allowances for the inevitable cost and schedule overruns, it was a remarkably different result from the original SEI.

What happened to make it fail: George H. W. Bush lost the 1992 presidential election and the Clinton administration was noticeably less interested in manned space exploration for its own sake. NASA reoriented itself toward keeping people in LEO, primarily building what had now become the International Space Station, and unmanned space probes beyond Earth orbit.

Extended manned lunar missions did creep back onto the agenda over the next few years, particularly as part of George W. Bush’s “Vision of Space Exploration” which pictured them as a test-bed for an ultimate Mars mission. But the discovery of water ice at the Moon’s south pole by the Clementine satellite in 1994 changed the nature of all future Moon base proposals by slewing them heavily towards using that water. Despite its generally innovative approach to a lunar landing, the First Lunar Outpost turned out to be the last gasp of an older paradigm for exploring the Moon.

What was necessary for it to succeed: This one is more speculative than most, but it’s interesting to consider the First Lunar Outpost in terms of what happened to Space Station Alpha in the same time period. The station came perilously close to cancellation and was only saved by a foreign policy decision: to turn it into the International Space Station, specifically in partnership with Russia in an attempt to absorb the time and skills of the Russian space engineers freed up by the collapse of the Soviet Union.

If you were looking to start an American make-work project in 1993 that capitalized on Russian expertise, a space station made the most sense. After all, Mir was beyond anything the United States had ever accomplished. But it’s not too hard to picture the busy-work being fulfilled by a different major space program. Since a manned Mars mission was out of the question due to expense, the relatively cheap First Lunar Outpost might have been the choice if the Clinton White House had been more interested in the inspirational side of space exploration than its nuts and bolts. They wouldn’t have been the first administration to feel that way.

LK-700: The Soviet Union’s Other Road to the Moon

LK-700 spaceship

Three views of the mockup of the LK-700 built before the program’s cancellation. On the left the craft as it would be at TLI, with its three lateral rockets. In the centre, a close-up view of the VA capsule, and on the right as the craft would appear on the trip back from the Moon (the lattice supporting it is not part of the craft). Image source unknown.

What it was: Vladimir Chelomei’s plan for a direct-descent lunar lander. While never the forerunner for a Soviet Moon landing, it was always a strong alternative that Chelomei and his supporters kept pushing forward whenever they could get a step up on Sergei Korolev or Vasili Mishin.

Details: For a very short period of time Vladimir Chelomei was on the verge of becoming the top man in the Soviet space program, and used his influence to cut Sergei Korolev’s OKB-1 out of the USSR’s manned lunar flyby mission and replace it with his OKB-52. He never did manage to gain control of the manned lunar landing, which was always officially going to be the N1-L3 or a derivative, yet it’s clear that if Nikita Khrushchev had not been ousted from power October 1964 he would have pushed to take it over too—and very possibly would have got it. While strictly speaking the LK-700 didn’t come until after Khrushchev’s fall, it’s what we would have seen as the Soviet effort at a lunar lander if Chelomei had remained on top.

The LK-700 began as the LK-3, and was first formally proposed after Chelomei and Valentin Glushko had thoroughly studied their alternative to the N1, the UR-700. Unlike OKB-1’s rocket, which was repurposed from designs for a Mars mission, OKB-52’s proposed launcher had been built with the Moon mission in mind and though the LK-3 was not formally approved until October 1965—after Khrushchev’s fall— the two had apparently been worked on in lockstep since about 1962.

This meant that it had one intrinsic advantage when the N1-L3 program ran into weight issues. It had become clear in late 1964 that the first few N1 rockets were not going to be powerful enough to perform a single-launch Moon mission, and that OKB-1 was going to have to evolve their launcher into something that could do the job. As the UR-700 and what was now the LK-700 were designed for each other, they would have been able to go on an earlier flight and so—all else being equal—get to the Moon first. The October 1965 decision to stick with the N1 but also move ahead with Chelomei’s plan, albeit at a much lower level of funding, was specifically intended as a backup if the N1 turned out to be a failure. From then on the advancement or retardation of the LK-700 tracked the N1’s highs and lows.

The LK-700 also had the advantage of being quite conservative. It was a direct-descent lander, which meant no dockings in space, whether in Earth orbit or around the Moon; as that profile needs more mass the rocket itself had to lift a larger payload, about 150 tonnes, but would be based on the tried-and-true storable propellants nitrogen tetroxide and UDMH. So would the LK-700—the highly toxic nature of the fuel was glossed over.

A Moon mission on the LK-700 would see two cosmonauts (or three in later missions) be launched into a 200-kilometer parking orbit by Glushko’s proposed booster. There they would spend five orbits checking out the craft’s systems before committing to a trip to the Moon. The fully-fuelled craft would weigh some 154 tonnes, as mentioned, and be about 13 meters long (not counting its abort tower, which brought the length up to 21.2 meters during launch). This is immense compared to the L3 proposed by OKB-1, and would have even been larger in mass than the Apollo CSM and its S-IVB injection stage at trans-lunar injection if fuel is included.

The Apollo craft was considerably longer than the LK-700 would have been, though. Rather than use Apollo’s linear arrangement with one engine and tank on the injection stage and the actual spaceship perched on top, the LK-700 would have used a laterally clustered arrangement. Three of a proposed new engine, the 11D23, would be attached to tanks of propellant arranged in a trefoil around another 11D23 and tank attached to the aft end of the LK-700’s crew capsule (the VA) and lunar landing stage/ascent stage (the Block 1V). The three engines would fire to add another 3.1km/s to the LK-700’s speed and send it on its way to the Moon, at which point they would be jettisoned.

The fourth engine and its propellant (Block 11), still attached to the outbound craft, would be used for course corrections during the 80-hour journey to the Moon. Upon arrival the Block 11 would fire again to slow the craft down to about 30 meters per second somewhere between three and five kilometers above their destination—notionally the Mare Fecunditatis, though Chelomei’s bureau never got anywhere near actually picking a landing site.


A view of the Block 111 landing gear. The rest of the craft sat on top, with the landing/TEI engine protruding out the bottom. It would remain behind on the Moon. Image source unknown.

At that height the Block 11 would run out of fuel and be ejected, exposing the Block 1V engine. The LK-700’s landing platform and gear (AKA Block 111) enclosed the Block 1V cylindrically, but let the rocket fire downwards to bring the craft to a soft landing on the Moon. The ship would have been designed to stay on the Moon for 12 to 24 hours, during which time the two cosmonauts it carried would make two surface excursions between two and two-and-a-half hours long.

When it was time to leave the Block 1V would fire again and launch the LK-700 back toward Earth while leaving the Block 111 behind. This would be a direct injection towards home, meaning that unlike the Apollo landings or the N1-L3 there would be no orbiting of the Moon either on landing or takeoff. This had the advantage of opening up a much larger fraction of the Moon’s surface for exploration, as there was no need to stay within the belt around the Moon’s equator where an orbiting mother ship would fly over the landing site with regularity.

The return journey would be somewhat slower than the outbound, taking four days, and after re-orienting the craft for re-entry at 150 kilometers above the Earth, the VA crew capsule would separate from the rest of the ship at 100 kilometers. The LK-700’s capsule was quite similar in shape to the Apollo CM, though considerably smaller: 3130kg as compared to 5809kg, and an interior volume of 4.0 cubic meters as compared to 6.17. Having the same outline and comparable small thrusters gave the VA the same rough steerability as an Apollo CM, and the crew aboard the last remaining component of the LK-700 could aim for a particular spot in the Soviet Union with about 11,000 kilometers of downrange and 300 kilometers of cross-range performance. Like other Soviet manned spacecraft, it was designed for a soft landing on land.

What happened to make it fail: Even though Chelomei was never able to get enough of the Soviet leadership to support his program over the N1-L3, the LK-700 trundled along at a low level for quite some time. The Central Committee of the Communist Party (at that time in the ascendance because of its support for Leonid Brezhnev’s takeover) re-authorized continuing work on it in September 1967. In the wake of the second N1 explosion in 1969, Chelomei even felt confident enough to push for the cancellation of the N1-L3 and its replacement with an LK-700/UR-700 based mission, making the good argument that re-designing and re-certifying the N1 so that it would stop blowing up on the pad would cost just as much as building the UR-700 anyway. Perhaps unfortunately for the USSR’s lunar landing ambitions that effort also failed to get enough backing and the N1 continued.

In the real world the LK-700 reached the mockup and early testing phase when it was killed definitively in 1975, along with all other Soviet Moon landing and flyby plans, by that shift in viewpoint towards space stations, Energia, and a Soviet space shuttle.

What was necessary for it to succeed: The LK-700/UR-700 was a very creditable attempt to make a Moon mission and certainly could have succeeded if technical skills were all that were necessary. Vladimir Chelomei had notable successes in his future, while the UR-700’s Valentin Glushko is arguably the greatest rocket engine designer of all.

Instead it never came to pass purely because of the poisonous politics of the Soviet space program from 1964-1975 (though of course if they hadn’t been like that it’s unlikely Chelomei would have been able to work on it at all once the decision was made to go with the N1-L3 in 1965). So at first the obvious answer to this question is “Vladimir Chelomei has to be able to maintain his remarkable drive to the top of the Soviet space program, rather than fall even more quickly than he rose”. To that end the continuing rule of Nikita Khrushchev would work very well, though it isn’t strictly necessary.

The main difficulty with this answer is Chelomei’s speed in developing his ideas. He had a strong tendency to go his own way and come up with unusual, if plausible, ways of solving problems. As a result his programs often required considerable fundamental work and testing as compared to more conservative approaches to the same problem. To his credit he took that time whenever it was politically possible to do so, but it meant long waits before missions were ready to go. While he would have been able to move considerably faster if OKB-52 had had the funds that OKB-1/TsKBEM had for the N1-L3 program, his deliberate pace on his other more successful projects strongly suggests that he would not have been able to beat the United States to the Moon by July 1969.

At that point the question becomes one of the Russian leadership’s attitude to a Moon landing after losing the race. It’s likely that the UR-700/LK-700 combination would have been less accident-prone than the N1-L3 (it hardly could have been worse), and so it seems that the Kremlin might have been greater tolerance for it if it ran late. Ultimately the success of the program would have come down to a race between Chelomei’s dream and a cancellation brought about by a desire to save money or (as in real-life) a re-orientation of the USSR’s space program toward military objectives. If the dream won the contest, a cosmonaut would have set foot on the Moon sometime around 1975-1980, with a likely Soviet Moon base to follow; if not, then we’d have seen an outcome rather similar to what happened in the real world, with only the doomed technology being different.

Sidebar: Von Braun’s Moonship


Detail from the diagram of Wernher von Braun’s conjectural Moon ship published in the Collier’s Magazine issue of October 18, 1952. Click for a larger, complete view of the whole diagram.

Wernher von Braun, Willy Ley, Fred Whipple, and others famously jump-started American interest in space with their series Man Will Conquer Space Soon!, published over eight different issues of Collier’s Magazine between March 1952 and April 1954. This is from the second one, October 18, 1952’s “Man on the Moon”.

Though unsigned, it is likely the work of magazine artist Rolf Klep—Chesley Bonestell is remembered for the paintings he did for the series, but Klep did most of the more diagrammatic images. It depicts two variants of the same basic ship, one a passenger ship and one a cargo ship. Both would have been built in orbit after a space infrastructure of orbital rockets and a space station had been put in place.

Two of the “passenger” version would have carried a total of 50 scientists and technicians between them, while the “cargo” version would have been on a one-way trip to the Moon carrying the supplies the 50 men (and the title of the series leaves little doubt that it would have been only men) would need for a six-week stay on Earth’s nearest neighbour. Their goal would have been the Sinus Roris near the Moon’s North Pole—and later used by Arthur C. Clarke as the setting of his A Fall of Moondust, in all likelihood because of its mention in this article.

The ships are 160 feet tall, which is to say just about the same height as the entire Space Shuttle stack. They were to have burned nitric acid and hydrazine, which was quite prescient on the part of Dr. von Braun as that’s one of the three most popular rocket fuel combinations (along with LOX/LH2 and LOX/Kerosene) down to the modern day. Less prescient is its mercury-vapour powered turbine, which uses the parabolically concentrated light from the Sun to evaporate liquid mercury and generate 35 kilowatts. They were the hot new thing in 1952, but fell out of favour not long after. So far as I know there’s never been one in space.

Naturally on arriving at the Moon, the astronauts would set about building a Moon base using the cargo they brought as well as the one ship that brought it. From there von Braun confidently predicted that it would not be too much longer before the first manned trip to Mars ensued.

While this ship was never a serious proposal like all the other posts to this blog have been, it’s historically significant. Though published in 1952 it originally dates back to a non-fiction book written by von Braun in 1948, Das Marsprojekt. Bearing in mind that this is only three years after he was forced to leave Germany, it likely reflects his long-term goals for the German V-rocket program. As is well-known, he was highly interested in diverting it from focusing solely on weaponry into space exploration—indeed the winged rocket ships used to get von Braun shipwrights into orbit to builld these Moon ships look like a hybrid of the most speculative and advanced idea Peenemünde floated, the A12 and the winged A6. Who knows? In a different, more peaceful world we may have seen Germany sending something like this to the Moon in 1980, dedicated to the memory of the recently deceased father of the German space program.

Soyuz L3: The Chief Designer’s Moon Landing


The full L3 craft leaves Earth orbit. The lunar orbiter is the green portion to the right, while the lander is covered by a fairing to the left of the gold-coloured portion until reaching the Moon. Image by Eberhard Marx and used under a Creative Commons Attribution 3.0 Unported license. Click for a larger view.

What it was: The Big One. This was the Soviet Union’s main response to the US’ Apollo program, running from Sergei Korolev and OKB-1 formally wresting the Moon landing from Vladimir Chelomei in 1965 until after the landing of Apollo 11. It would have sent two men to the Moon aboard a customized Soyuz, one of whom would then enter the purpose-built LK lunar lander and descend to the surface. Apart from the smaller crew, it was similar in many ways to the Apollo approach.

Details: For a period of about a year beginning in August 1964 the composite Soyuz craft originally intended for the Soviet Moon mission, the 7K/9K/11K, languished as responsibility for landing a cosmonaut on the Moon was given instead to Vladimir Chelomei. Recognizing that his original conception was not moving forward, in February 1965 Sergei Korolev re-oriented his approach to work solely on the 7K and Earth-orbital docking maneuvers, a variant called the 7K-OK. This version of the Soyuz was approved in February 1965.

At the same time, Korolev had no intention of giving up the Moon mission. The 7K/9K/11K would have required multiple launches to build and fuel in Earth orbit, so at least partially for the purpose of making the mission simpler and cheaper OKB-1 switched proposals to a Lunar Orbit Rendezvous profile that would need just one N1 launch. Then Korolev went back to work on the Soviet leadership; by February 1965 he’d convinced them to at least let him look at the manned mission, and by October he had managed to kill most of Chelomei’s programs. The other designer was left with only the UR-500K booster (which would become the Proton) for the manned circumlunar flight, but with a Soyuz derivative (the Zond) as the capsule. For the next several years the manned Moon landing would be in the hands of Korolev and his successors as they worked to develop the L3—a Soyuz 7K-OK variant called the LOK (Lunniy Orbitalny Korabl or “lunar orbital ship”)and a lunar lander, the LK (Lunniy Korabl, or “lunar ship”)—to sit on top of the N1 rocket that would be developed at the same time.

The work was primarily that of his successors, as Korolev died in January of 1966, his lieutenant Vasili Mishin took over OKB-1, and the bureau was re-organized as TsKBEM. The N1-L3 project became the deceased Chief Designer’s legacy to the Soviet space program.

What they came up with was a remarkable arrangement. Due to the lower payload capacity of the N1 (95 tonnes as compared to 120 for the Saturn V) and the tendency for 60s-era Soviet hardware to be on the heavy side anyway all else being equal, the LOK and the LK had to be smaller than the equivalent Apollo craft—9850 kilograms for the former and 5500 kilograms for the latter. By contrast the Apollo CSM by itself massed 30,322 kilograms even before getting to the LM. Accordingly the mission would carry only two cosmonauts, one of whom would go down to the surface. Three teams of two were selected as the best for this mission: Alexei Leonov and Oleg Makarov were considered the likeliest, with Leonov being the one to walk on the Moon. The other two teams were Valeri Bykovski and Nikolai Rukavishnikov, and Pavel Popovich and Vitaly Sevastianov—the former in each pair being the Moon walker.

The surprisingly large difference in weight between Apollo and L3 was necessary because not only were the three stages of the N1 necessary the L3 into orbit, the craft that left Earth had another two (compare Apollo, which got sent on its way by the third stage of the Saturn V, which was only partially spent by the climb to orbit). Having been lifted to LEO, after one orbit the first stage of the L3 would perform the translunar injection burn and start the cosmonauts on their long journey to the Moon; having performed the burn, it would be jettisoned and the remainder of the L3 would carry on.

Upon arriving at the Moon, the second stage was the one that did the most work. It would first get the L3 into a circular parking orbit, and then when the descent began it would fire to get the whole craft down to a perilune of only 16 kilometers.

This leads to another difference between Apollo and the L3. Shortly after leaving Earth orbit, the Apollo stack would reconfigure itself by having the CSM move away from the rest of the craft a short distance, rotate 180 degrees, and then return to dock with the LM nose-first. This opened up an internal transfer tunnel between the two before the trip to the Moon. The L3, by contrast, stayed in one piece during its journey. Once the ship was in its low-flying lunar orbit, the cosmonaut who would be making the trip down to the surface would leave his fellow traveller in the LOK’s descent module, put on his Kretchet-94 spacesuit in the orbital module, seal off the hatch between the two, and then exit the Soyuz out the main hatch. He would then spacewalk to the LK along the side of his ship using a variety of handholds including a pole connecting it to the LOK.


A comparison of the LK lander with the Apollo LM. For obvious reasons, the LK could carry only one cosmonaut. Public domain image via Wikimedia Commons. Click for a larger view.

Once aboard the LK, the cosmonaut would disconnect the lander and the second rocket stage from the rest of the craft and fire the latter to begin the final descent. Now burning for the third time, the rocket would actually get him down to 1500 meters before being jettisoned to crash on the surface nearby; at this point the LK’s engine would kick in. From that moment the pilot had one minute to find a landing spot—half the time an Apollo LM had. It’s worth pointing out that, unlike for the American astronauts, the Soviet pilot had the option of going longer if he needed to: the LK had only one rocket motor, and so his final descent engine was actually his ascent engine too. If he wanted to, he could eat into the fuel he needed to get back into lunar orbit to extend his landing time. Though obviously it wasn’t a good idea to keep this up for long, it made the LK a little more flexible and arguably safer than the American LM. The US’ lander had two motors, one for landing and one for return, and if the landing engine ran out of fuel while still in the air there was a height below which it wasn’t possible to start up the ascent engine in time to prevent a crash (this largely explains why Mission Control had “a bunch of guys about to turn blue” as Neil Armstrong coasted a few meters above the surface hunting for a landing spot in Eagle).

How long the LK would stay on the Moon was never determined, but it couldn’t have been too long as it’s known that there would have been no sleep period for our lone cosmonaut. The EVA on the surface would have been about four hours, during which he would obtain samples and set up the mission’s weight-limited experiment suite. As well as two seismometers, this would have included a mini-rover attached to the LK’s landing gear by a cable for power and telemetry—after the explorer left to go home, Soviet scientists back on Earth could drive it around and continue exploring the site by remote control.

Once the EVA was completed, the cosmonaut would reboard the lander and blast off for the LOK in orbit, leaving behind the LK’s landing legs as dead weight. The LOK’s pilot would home in on him and dock by means of a near-foolproof arrangement that simply required a spike-like probe on top of the LOK to punch out any one of 108 hexagonal cells contained in a large “shade” on top of the lander for solid contact. Having joined back up the moonwalker would then spacewalk a second time, back to the LOK.

From then on the L3’s mission profile was very similar to the Apollo landings. The LK would be jettisoned, and the LOK’s engine would perform a trans-Earth injection burn to get them home. Upon arrival at Earth the Soyuz would make the usual three-part separation of its type, the propulsion and orbital modules being allowed to burn up while the re-entry module made a more controlled descent. If possible, it would skip off the atmosphere to land somewhere in the Soviet Union (preferably the Kazakh SSR), but if not it would land in the Indian Ocean to be picked up by Soviet naval units strung all across its basin.

Before sending out the mission, the LOK and LK were tested a number of times. The LK proved to be quite successful: on November 24, 1970 one was launched into Earth orbit, left for three days to simulate the journey in vacuum to the Moon, and then run through the various burns it would need to land, wait while its hypothetical cosmonaut walked on the surface, and then take off again. It did so, and then remained in orbit until re-entering uncontrollably over Australia in 1983. Interestingly, the USSR felt it diplomatically necessary to explain to the Australian government that it was just a lunar lander and not a nuclear-powered satellite like Cosmos 954, which had come down over Canada in 1978 strewing radioactive waste in its wake. This was the first crack in the Soviet post-Apollo 11 cover-up and denial of their manned Moon landing program.

Three more LKs would be launched and tested in orbit by August 1971 and so it was ready to go, but circumstances make the LOK’s readiness more of a mystery.

What happened to make it fail:  The L3 was part of the larger N1-L3 program and so the decision to go for a single-launch, LOR mission was fateful. Many of the N1’s problems came about because now it needed to be upgraded from its initial design of 75 tonnes to low Earth orbit. This wasn’t enough to lift the LOK, the LK, and the craft’s two fuelled rocket stages, and so every method possible was used to squeeze another 20 tonnes out of the rocket, much to its detriment. A dummy 7K-LOK made it into orbit on top of a Proton on December 2, 1970, but two other attempts (one dummy and one real one) were aboard the final two tries at launching an N1, and so failed when those rockets exploded—though both times the LOK was recovered by their emergency escape system.

Even beyond the N1’s troubles there were a number of places where the Soviet Union made time-wasting mistakes as compared to Apollo. For one, they were very late in starting: Korolev had been pushing for a manned mission to the Moon since Kennedy made his challenge, yet formal approval for the project didn’t come until August 1964.

Even then the Soviet Moon program was split between two designers. In August 1964 it was Vladimir Chelomei who was given the assignment because he’d had the political savvy to give Khrushchev’s son an engineering job. After Khrushchev fell from power it took another year for Korolev to get the Moon program assigned to him instead. Essentially real work on the L3 couldn’t begin until the end of October 1965.

Chelomei’s continuing presence in the lunar flyby program was a problem too. Unlike Apollo where the same craft was used for both flybys and landing missions (the CSM), using a Proton for the flyby forced the Russians to develop two related-but-different craft, the 7K-LOK and the much stripped-down Zond. This duplication of effort wasted time and resources.

Korolev’s death and replacement with Vasili Mishin also hurt. While his contemporaries generally say that he was comparable to his predecessor as an engineer, they also say that he didn’t have Korolev’s people skills—including the political skills to impose his ideas on 1960’s-era Soviet leadership. Some even say that they believe that, given more time, Korolev would have eventually managed to cut Chelomei out of the picture entirely and ended up with a proper, single effort to get the USSR to the Moon.

This led to the final problem. As the other approach to saving weight was downgrading the spacecraft, even to the casual eye it was an inferior craft to the Apollo CSM/LM, not only in crew size but in the relatively primitive way the LK’s pilot had to spacewalk from the LOK just to get to his craft. The L3 would have been a triumph if it had got the Soviet Union to the Moon prior to Apollo 11, but once Neil Armstrong put foot to the Sea of Tranquility it was obviously second best. The Soviet Union’s leadership lost interest in the L3 mission for fear that it would look like a weak response to the American triumph. It sputtered along for a while (note the various post-May 1969 dates mentioned for the tests above), but Mishin’s TsKBEM was instead directed to work on the more ambitious three-man L3-M instead and told that only that would be acceptable for the actual mission.

What was necessary for it to succeed: Essentially they needed to pick something and stick with it, and continue on even if they “lost” to the US.

The infighting between Korolev and Chelomei left the Soviet manned space program in disarray, and even when it was supposedly settled it was with a solution that satisfied no-one. Korolev needed that extra year that was wasted in 1964-65, while simply letting Chelomei get on with it might have produced a Moon landing too—he was slow but talented, so while he may not have put a Russian on the Moon before about 1975, he would have done it.

This all assumes that the Soviet leadership put any value on the Moon program beyond its propaganda value, or could be convinced that there were still accomplishments to trumpet after the Americans beat them to the Moon. This is very difficult to see, as the leadership was right—given the amount of money they were going to have to spend, the returns of a manned Moon landing were very weak without some prestige to squeeze out of it too. The Soviet Union needed to get there first or else there was no point in going.

This is actually the real problem, since it’s unlikely that the USSR was going to get to the Moon before the US with the four-year head start they gave their competitors. The Soviet Union’s successes in space depended on getting the jump on the US, as they certainly weren’t going to beat them in resources or technical savvy. Ultimately once the Americans got going on the project, control of the race was out of the Soviet Union’s hands—they needed the Apollo team to make mistakes that let them catch up, and as we know the US made only one serious mis-step, with Apollo 1. It wasn’t enough.

The Martin 410: Apollo of Santa Ana


A cutaway view of the Martin 410 as it would have been configured en route to the Moon (excepting the escape tower, at left, which would be ejected after launch). Note the lifting body shape of the crew compartment, and the stubby cylinder of the habitation module enclosed in the larger toroidal equipment and propulsion module. Image from Glenn L. Martin Company’s “Apollo Final Report: Configuration” delivered to NASA in 1961. Click for a larger view.

What it was: One of several formal proposals made to NASA in 1961 as part of the design competition for the Apollo spacecraft. It had certain similarities to the one that was actually built (as did all of the proposals, as they had to meet criteria set by NASA) but was primarily different in two ways. As Apollo was still pictured as a direct descent mission at the time, it didn’t use the Lunar Orbit Rendezvous technique that was used for the real missions, and the re-entry vehicle was a lifting body instead of a ballistic capsule.

Details: On October 9, 1960, fourteen different companies answered NASA RFP-302, which asked them for feasibility studies on advanced manned spacecraft for the upcoming Project Apollo. Among them were Lockheed, Boeing, General Electric, and Grumman, as well as the subject of this post: the Glenn L. Martin Company of Santa Ana, California.

Within two weeks the contest was down to three: GE, Convair, and Martin with what they called their Model 410. Up against the contractors was an internal design by NASA’s Langley Research Center, specifically their Space Task Group, which had designed the Mercury capsule. Time passed and with the agency buoyed by the first successful American manned spaceflight on May 5, 1961—Alan Shepard’s Freedom 7—May 17 saw the final proposals for all four on NASA desks and the process of evaluating and deciding between them underway.

Eight days later John F. Kennedy challenged Congress to achieve “the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth”, and things changed—the White House had had its interest piqued back in October when the study contracts were awarded and had been working behind the scenes with NASA. The Langley group rapidly metamorphosed into the much-larger Manned Spacecraft Center—now the Johnson Space Center—and by September started the move to land in Texas donated by Rice University (which is why Kennedy’s second famous space speech, the “We choose to go to the moon” one, was made there).


The suggested layout of the Apollo spacecraft for the second phase of the competition. Note the considerable similarity to what actually got built. From Chariots for Apollo: A History of Manned Lunar Spacecraft. Click for a larger view.

Even before then, the Langley group had swung into action. Their chief engineer was Maxime Faget, an American of Belizean birth, had designed the Mercury capsule, and his head of engineering (Canadian Jim Chamberlin, formerly of Avro) was in the middle of designing the Gemini. Their job was to synthesize what the contractors had developed with their own design and use it to develop a new set of specifications—in actuality, a nearly complete design of its own—that could meet Kennedy’s challenge. While the three previous contractor proposals had been paid for by NASA to the tune of US$250,000 apiece (though all of them took a loss, spending in excess of $1 million apiece), the other contractors had been encouraged to carry on with their work on their own. This attitude now paid off: a new competition was begun for a final design, open to all groups who’d tried back in October not just the three previous winners. On July 28 twelve contractors (two had dropped out back during the first phase, Cornell and Republic Aviation) were asked to submit again based on the new prerequisites. Several of the contractors teamed up with each other, reducing the number of replies to five, but Martin once again went with the M-410 on their own.

Not counting the rocket adapter ring (which all the proposals had so they could mate to the upper stage of a Saturn), the M-410 was made up of three parts: a command module for use any time an engine was burning and for re-entry, a mission module in which the crew would live at other times, and a composite equipment and propulsion module.

The command module was the most interestingly divergent component compared to the Apollo spacecraft that actually got built. All three contractors evaluated ballistic, winged, and lifting body re-entry vehicles. The latter was a particular one NASA called an M-1, and Martin went above and beyond by evaluating a number of other shapes in all three categories before settling on a variation of the M-1. Their solution made the M-410’s re-entry moderately controllable, especially as it would have had four control flaps; Martin considered this a big improvement on Mercury or the Soviet Vostok. It would have been built out of aluminum alloy, and had a composite heat shield made out of ablative material and a superalloy (undecided at the time, but something like René 41 or an Inconel). The version of the M-410 submitted post-Kennedy’s speech was also unusual because of the four rectangular flaps that would deploy from its underside, which would expose solar panels to power the craft. During launch the command module had an emergency escape tower perched on top of it, though this would be jettisoned on reaching 90 kilometers in height.

The three crew would live for the majority of their mission in the mission module. This supplied a little over eleven cubic meters on top of roughly the same for the command module (contrast this with the 12.9 cubic meters of the combined Apollo Command Module and LM).

These two were then mated to the equipment and propulsion module. As well as the usual electronics for a Moon-bound manned spacecraft, it packed a single LR-115 engine (a design which later evolved into the R-10 and derivatives used for the Saturn I and the Centaur) and 4740 kilograms of liquid oxygen and liquid hydrogen.

Having launched in an unspecified way (NASA was still trying to decide if they were going to use multiple smaller rockets to establish a fuel depot in orbit, or go as they actually did with a larger rocket like the Saturn V), Martin suggested that the M-410 be sent on its way to the Moon using a lower stage attached to the rocket adapter ring. This stage would have contained roughly 13 tonnes of LH2 and LOX and been pushed by three LR-115s.

This was powerful enough to get it down to the Moon, because the entire thing was designed to land there. Exactly how this was to be accomplished remained to be seen, as NASA was then in the middle stages of its most historic argument: land directly via an Earth Orbit Rendezvous profile, or send a separable landing module and rendezvous above the Moon. Going in to the proposal period it was assumed that the former was likeliest, though the contractors were asked to consider what they would have to do if the latter won (as, of course, it did).


One of the ideas studied, but explicitly rejected, for giving the M-410 artificial gravity: spin it up using the booster stage as a counterweight. From “Apollo Final Report: Configuration“. Click for a larger view.

Assuming it did land directly, though, the lower stage would be left behind as the propulsion module had sufficient thrust to lift itself back off the Moon and home to Earth. One thing the lower stage would not be used for was the generation of artificial gravity—Martin took the time to figure out if it were possible to generate a bit of it during the mission, including putting the lower stage out on a tether and using it as a counterweight to spin up the rest of the craft. They decided that for a trip as short as one to the Moon it wasn’t worth the extra weight needed for systems that could pull the trick off.

At the end of the mission, the command module would separate from the rest of the craft and re-enter. The M-410’s CM lifting body was designed to touchdown on water or land, with a combination of parachutes and retrorockets slowing it to just one meter per second as it touched the ground.

What happened to make it fail: On October 9, 1961 the new proposals were received, and two days later the five competing contractors gave presentations on their work. The evaluations began immediately thereafter, and were completed on October 28th. At the end of the competition, the M-410 was first with an average score of 6.9 points in each of the categories that NASA had outlined. Next came General Dynamics and North American Aviation, tied for second with 6.6 points; the GE-led and McDonnell-led contractor coalitions were the also-rans.

Despite the win Martin lost the contract to North American on November 28, 1961; NAA would go on to build the actual Apollo CSM. NASA administrator James Webb and his deputy Robert Seamans justified their decision on the basis of an external factor: NAA’s experience building the X-15.

The real reason is widely believed to be that North American had made the conscious decision to stick as closely as possible to Max Faget’s post-synthesis Langley design, and that NASA wanted that regardless of the merits of any other approach. Faget reportedly had been annoyed by the fact that none of the three initial designs had gone for a blunt-body re-entry vehicle, which was why he had come up with the Langley design in the first place and then convinced the agency to re-open the competition. He then had enough influence to disqualify any bid that didn’t follow his lead, including the Martin 410.

From this point onwards (and most noticeably in the proposals for the Space Shuttle a decade later, excepting the oddball SERV) NASA contractors understood that the implicit rule in any spacecraft design competition was “What Max Faget wants, Max Faget gets”. Despite the obvious possibilities for disaster with this approach giving him a veto turned out to be a pretty good idea: history has proven Maxime Faget was a talented spacecraft designer, arguably the best ever.

What was necessary for it to succeed: Not an awful lot more than what actually happened—the M-410 is one of the likeliest “what-ifs?” of the Apollo program.  It won the Apollo design competition, and if a small number of people (Faget, Webb, and Seamans) hadn’t been able to shift the results arbitrarily, it would have gone ahead. There would have been changes made, as happened in the real world to NAA’s design between 1961 and the first completed Block II Apollo craft flown in October 1968, but otherwise this design could have gone to the Moon.

The Armstrong Whitworth Pyramid: For an Empire on the Up


A diagram of the Pyramid re-entry vehicle as presented to the British Commonwealth Space Flight Symposium in August 1959. The basic design with is on the left, while the variant with caret wings is on the right. The crew would have resided in the small cylinder outlined with dashes in the centre of the craft. Click for a larger view.

What it was: A proposal put forward in 1959 by Armstrong Whitworth, a British aircraft manufacturer, to build a pyramidal spaceplane to put on top of a two-stage rocket composed of a Black Knight rocket poised on a Blue Streak missile (this latter arrangement actually becoming official less than a year later, as the Black Prince launch vehicle).

Details: The UK is the only country in the world to have developed a space launch capability and then give it up (one could make an argument for France as well, as the Ariane is technically European, but that rocket is clearly France’s baby). That said, at the end of 1945 the UK was one of the few countries on the cutting edge of rocketry—like the US and Soviet Union they benefited from the ransacking of the German rocket programs. For a period of roughly twenty-five years after that up to 1971 the UK did try to keep within striking distance of the pace set by their two rivals, and in the period immediately following Sputnik there were grand plans to get men into space too, plans only struck down by Britain’s poor economy as compared to the US and an inability to shoot dissenters as the USSR had in its favour. To paraphrase Dean Acheson, it was all part of Britain losing an empire and trying to find a role.

The ultimate expression of this was the Pyramid. The basic idea behind the craft actually dates to 1951, when as we’ve discussed previously the University of Belfast’s Terence Nonweiler invented the concept of waveriding: increasing lift by riding the shockwave generated by a hypersonic aircraft. By 1956 the British had begun slowly working on this; after Sputnik I was launched they greatly increased their pace.

In 1957-58 Armstrong Whitworth, part of the Hawker Siddeley aircraft consortium (which also included Avro Canada, of Avro Arrow fame) worked out a shape that would be able to waveride back to Earth from orbit and, more importantly, orbital speeds. At that time the equations used to model hypersonic aerodynamic flow were crude, and the answers they gave had to be calculated by hand, so the shape was as simple as possible: take a regular tetrahedron and push its top point down to produce a squat pyramid. Then take one of the base points and pull it out by about half until you have something resembling the platonic ideal of an airplane. For simplicity’s sake, the underside stays completely flat. The only wrinkle is the addition of two rudders on horizontal tail structures at the aft end of the craft, and in one variant two small caret wings (the designers also realized that the real Pyramid would have to have rounded edges and a blunted nose to keep sharp edges and points from burning off during re-entry).

As designed, the Pyramid would have weighed 1876 kilograms, somewhat larger than a Mercury capsule’s 1104 kilograms, but in the same range (a Gemini capsule weighed 3396kg). It would have been 7.7 meters long and 5.2 meters wide, with a height at its point of 2.8 meters—though as it was a flat pyramid much of its length was considerably lower than that. Under the point and the rear facet of the pyramid was the crew capsule itself, which would be cylindrical and contain two men. As was typical for very early spacecraft designs, its engineers were overly optimistic about how many astronauts could be crammed into a small space.

The craft would have been launched on a proposed launcher involving a Blue Streak missile (an IRBM being developed by the UK for their nuclear weapons) as the first stage and a Black Knight rocket as the second. This was actually proposed more formally a few months later by the British government and given the name Black Prince, and so while it’s slightly anachronistic to call it that in the context of Pyramid, we’ll use that name here.


A view of the Pyramid on its rocket (though this one looks more like a US Titan than the Black Prince). The “mirror Pyramid” added to the Pyramid-proper for aerodynamic stability can be seen here. Originally published in Flight magazine, August 1959, and so believed to be in the public domain. Click for a larger view.

The Black Prince wouldn’t have been capable of getting very much into orbit (it would have been hard-pressed with a payload of 100kg), so Armstrong Whitworth suggested killing two birds with one stone. The Pyramid would also be much too wide to fit into an aerodynamic fairing on top of its rocket, and as it generated lift at low altitudes it would try to push the rocket off course and make the climb into orbit all that more difficult. So the Pyramid would have been paired with an identically shaped fuel tank mated to its underbelly, balancing its aerodynamics and supplying more propellants to the first stage. Once the first stage had lifted the whole arrangement as high and as fast as it could take it, it and the mirror-Pyramid would be jettisoned and the second would carry the real Pyramid into a 130 by 650 kilometer orbit.

Once the mission was done, the Pyramid carried just enough fuel (only a few kilograms) to perform a retro-rocket burn at perigee, which would knock it down to 100 kilometers and allow it to re-enter. Here the waveriding aspect of the craft would kick in. At a high angle of attack a lifting shockwave would form on the flat underbelly and let the Pyramid guide its path; it could even perform a sinusoidal flight following successive great circle paths to minimize the amount of heat the underbelly had to absorb.

The designers were concerned that their original design was unstable at speeds below 130 km/h, and they didn’t know enough to make it so, so the plan was for the crew to eject out of a hatch in the rear of the Pyramid once they were low and slow enough to parachute to safety. The ship would then crash, obviously reducing its reusability. Armstrong Whitworth believed that after harvesting data from a few flights, though, they would have learned how to proceed so the future Pyramids could land safely. Then the hatch would serve for emergency exits only.

Long term planning-borderline-dreaming for the Pyramid was to upgrade the Black Prince with a cruciform set of ten engines and then stick a nuclear second stage on top of it. With that booster, the Pyramid could be given a landing engine and head for the Moon. As seems surprisingly common for early proposale, they even had a landing site picked out: Piazzi Smyth Carter near the eastern edge of the Mare Imbrium. After a few unmanned cargo launches, the manned mission would consist of several Pyramids landing their crew simultaneously nearby and getting to work on a Moon base.


An image of a Pyramid on the Moon, from “Surface Exploration of the Moon” in Spaceflight magazine, August 1961. Image believed to be in the public domain. Click for a larger view.

What happened to make it fail: The Pyramid can be broken down into two pieces, the re-entry vehicle and the rocket on which it was perched.

The crewed section failed for the usual reason: it was a paper proposal looking for government funding and it didn’t get it. The window for it to get that funding was particularly small too, as it was a primitive design and would have been completely obsolete based on what had been learned the previous few years if it had got underway by, say, 1963. That said, there were some wind tunnel tests on it, and Hawker Siddeley did study another, more sophisticated waverider in 1971; that system was radically different, being lofted by a winged booster and having an on-board ramjet.

The 1959 Pyramid’s rocket was more successful, bearing in mind that “successful” here is a relative term. As mentioned earlier, the Black Prince was actually given the go-ahead a few months later, but the reason for this was complex. The UK had been pouring money into the Blue Streak missile and, out of embarrassment at its cancellation with no return on that investment, allowed it to go ahead as a civilian rocket. Political embarrassment or not, the Treasury was uninterested in funding space, and repeatedly tried to cancel every ballistic missile and space launcher project until an attempt stuck—and in the case of the Black Prince and its follow-ons, no-one was actually interested in sticking up for it. Ultimately it came down to a struggle between expensive British independence and prestige, or cheaply relying on the US for technology.

What was necessary for it to succeed: The Pyramid re-entry vehicle had a lot going against it. First of all, waveriding has never been well-developed, not even in the 21st century: only one craft has ever used it, the American XB-70, and that plane never went much above Mach 3. Furthermore, the Pyramid’s design was too small for the two men it was supposed to carry, so it would inevitably have had to undergo a radical redesign. It also became obsolete very quickly as manned space travel took several great leaps forward in 1960-65. The Pyramid also wasn’t an official government project, being a proposal from private industry that Armstrong Whitworth then had to convince the UK government to fund. With the Treasury opposing everything to do with space, it wasn’t going to get that. Altogether it was never going to fly, either because of money problems or because the design was not going to work as planned.

The rocket had a chance, though. The turning point there was probably the Nassau Agreement of 1962. After the cancellation of the Blue Streak, the UK had been planning to use the American Skybolt missile and when that was cancelled as well they were left in a dire situation as far as nuclear deterrent was concerned. Expensive or not, it looked for a while as if the UK was going to have to spend their way out of the problem and uncancel the Blue Streak. If so, the British would have had a much easier (and much better funded) path to the Black Prince that they could have taken.

Instead PM Harold Macmillan convinced John F. Kennedy to sell Polaris missiles to the UK. The Blue Streak stayed dead, and all of the UK’s independent space plans went with it over the course of the next few years. Change the course of history there and you might get the UK in space using Pyramid’s launcher

The Blue Streak cancellation notwithstanding, the launcher half of the Pyramid system did move ahead for a while. The embarrassment-driven Black Prince derivative proceeded until the end of 1960. The British couldn’t convince Australia or Canada to help finance it, though, so it too was cancelled, signalling the end of Britain’s large-scale ambitions in space.

It still stumbled along for several more years, morphing into two different projects, the British/French/German European Launcher Development Organization’s Europa (which was cancelled and replaced with Ariane in 1971-3) and the Black Arrow—both of which suffered from lack of support from the UK to the point of deliberately being set up for failure. Nevertheless the latter of these was launched four times, with the last being the first successful British launch of a satellite, Prospero, in October 1971. It was also the last: the Black Arrow program had already been cancelled in July, and the launch had only gone ahead because the final rocket had already been built and shipped to Woomera in Australia for its flight.

Project Horizon (Part III): Landing Soldiers on the Moon and Keeping Them There


A depiction of the construction of the second, larger part of the 12-man Moon base proposed as the end goal for Project Horizon. The initial part of the base, shown covered in lunar material at left, was to be built within two months of the first manned landing. The proposed Lunar Landing Craft can be seen soft-landing in the background. Public domain image from Project Horizon: Volume I. Click for a larger view.

What it was: The culmination of the US Army’s Project Horizon proposal of 1959: sending a direct descent/ascent spaceship to the Moon, then building and populating a twelve-man Moon base shortly thereafter.

Details: Having taken off from Christmas Island Launch Facility in the Pacific aboard a Saturn I to the Minimum Orbital Station (MOS), two Army astronauts would receive further fuel launches and then finally an unloaded Moon craft perched on top of a Saturn with a specialized third stage. The third stage has already burned through its fuel to get the heavy direct descent ship into orbit, so after matching orbits with the MOS the Moon crew and the other men living longer-term on the station refuel it. Then the two men bound for points further afield climb aboard and use the stage to burn for their trans-lunar trip.

As well as the TLI stage, the proposed Horizon lunar craft consisted of two more stages. One soft-landed the spaceship on the Moon, and the other would detach from that one (leaving it behind) and return its astronauts to Earth directly. It in turn would separate from a crew return capsule used for re-entry into the atmosphere and splashdown into the ocean.  Altogether this two-stage vehicle would have been some 16 meters long and weighed 64 tonnes. This is huge: the Apollo CSM/LM combination was 45 tonnes, and even at that carried three men instead of two. Even a Saturn V (which was still in its early development during the times of Project Horizon, and is only roughly spec’ed out as a “Saturn II” here) wouldn’t be able to lift that off of Earth, and so the need for refueling in orbit.

To make up for this, there were actually two different types of landers suggested, one of which could be launched directly from Christmas Island on a Saturn I. To meet that requirement, this second type would have been relatively small: 12 tonnes with a payload to the Moon of 2.5 tonnes, a figure made possible only by the fact that they didn’t have to return to the Earth. One would be sent before the first two astronauts started on their journey to the Moon, carrying construction materials for the base. By the end of 1966, there would be four in all sent on their way.

The first manned lunar landing, of two men, would be in April 1965, guided into the site where the base is to be built. In the 1959 report, the Army even had three possible sites picked out: “the northern part of Sinus Aestuum, near Eratosthenes, in the southern part of Sinus Aestuum near the Sinus Medii, and on the southwest coast of the Mare Imbrium, just north of the Appennies”; the last of these is actually not far from where Apollo 15 landed. The Army astronauts’ job would be to explore the immediate area and make sure that the site was acceptable for building a base. They would live in their landing craft until the construction crew arrived in July 1965 (ninety days or so, as compared to Apollo 11’s 21 hours and 34 minutes) at which point they would head home.


A cross-sectional view of the initial two compartment quarters that would house nine to twelve men while they built the larger remainder of the base. Public domain image from Project Horizon, Volume II. Click for a larger view.

This construction crew would consist of nine men, and they would get to work using explosives and tools to dig a deep trench in which they would build their own quarters within fifteen days (or at least no more than thirty) and then cover them with lunar material for protection; a ramp at either end would allow entry and exit from their quarters’ airlock. These accomodations would necessarily be Spartan, but when done the crew would have a small underground base with a cylindrical cross-section (double-walled with vacuum between for insulation), while leftover cargo pods and the like would be buried nearby to hold LOX/nitrogen tanks and waste. The crew would also set up two nuclear reactors to power the base and erect communications equipment so they could stay in permanent contact with Earth.

Now enhanced to twelve men by another landing, the construction crew would get down to building a second, larger cylindrical section at a right angle to the first. When completed the living quarters would be moved here, and it would also contain an office and a sickbay. The original cylinder would be fitted out as two labs, one for biological studies (the proposal charmingly suggests it could be used to check for life on the Moon) and one for physical experiments. The sections of the base wouldn’t link up, but the ramps on one end of each would touch for relatively easy access between them, or as easy as having to put a spacesuit on to walk a few feet can be. A diagram of a remarkably odd-looking spacesuit is included for reference in the report; it has mechanical hands (the astronauts’ real hands were to be cocooned inside the sleeves), and large plates attached to his feet to support him if the lunar dust turned out to be thick.


A diagram of the Horizon spacesuit. Note the odd mechanical hands and “lunar dust walking” plates. Public domain image from Project Horizon: Volume I. Click for a larger view.

By the end of 1968 there would have been ten manned missions in all to the Moon, and eight returns, meaning that the Horizon base would still be inhabited into the indefinite future after that.

What happened to make it fail: The first part of Horizon that we discussed, the launch facility, was perfectly well laid out and not overly different from what ended up being built at Cape Canaveral (though it was bigger and had more pads). The second part is more speculative and is fairly different from what actually happened, but this is mostly because of the change to a Lunar Orbit Rendezvous mission by NASA a couple of years after Horizon was proposed. Still, in retrospect it looks as if they didn’t quite think their station through.

When we get to this third part, though, the speculative nature of what the Army wants to do is front and center. The ways they propose to build and maintain a Moon base are bizarre to modern eyes, mostly because they literally didn’t know the extent of the problems they would face. A close read of the relevant documents reveals a large number of weasel words embedded in every attempt to describe the way things would be done on the Moon if Horizon got the go-ahead. Even Horizon’s summary report admits that the Army wanted another eight months and US$5.4 million dollars just to nail things down before moving on to starting the hardware development for the program.

Having a Moon base was a possible ultimate goal for an American space program, but planning one down to the point of having dates and proposed sites was very premature. Ultimately Project Horizon didn’t fool enough people into thinking that the Army knew what they were doing. Even looking past the previously-discussed antipathy that President Eisenhower had for the military in space, he was known to have used the words “Buck Rogers” more than once to describe the nebulous plans he got from the Army and others, and he was justified in saying so.

What was necessary for it to succeed: The Project Horizon proposal wasn’t actually about how to get to the Moon. It was an attempt by the US Army to establish precedence over the other armed services and, later, the upstart NASA. With Horizon filed away in various Washington bureaucracies, they could point at their long-standing work on manned space travel and plausibly say “Why give money to these newcomers? They’d be starting from scratch and you’d have to pay for that! Give it to us; it’s the wise course to take”.

Then, if anybody bought what they were selling, the way they actually went about it would conform to Horizon only incidentally as they got around to determining how to build this part of their empire. They could always go back and get more money and more time if they needed it, once the US committed to doing it through them.

So Horizon Base was never going to get built. It’s not an appropriate way for housing 12 men on the Moon because when it was designed the proper ways to do it were literally unknown, and would remain unknown for some time. But all it needed to succeed at its actual goal was to fend off Eisenhower long enough for someone in Congress to step up for them and ram through a bill giving the Army control of manned space exploration. It was a decent bet, just one that didn’t pay off.

Lunar Gemini: Take Two to the Moon

Gemini III Lunar Lander schematic

A schematic of the most capable of the proposed Gemini lunar landers, the Lunar Gemini III. Public domain image from Direct Flight Apollo Study, Volume II: Gemini Spacecraft Applications, written for NASA by McDonnell Aircraft in 1962. Click for a larger view.

What it was: A direct-ascent lunar lander based on the Gemini capsule, which would be mated to a lower landing and ascent stage and a rocket stage that would get it to the Moon. Two men would travel in it, land on the Moon, and return to Earth in it, no docking required.

Details: One of the main factors that made the United States the winners of Kennedy’s lunar landing challenge was their focus. In contrast with the Russian program, which was constantly torn between three visionary designers (Korolev, Glushko, and Chelomei), the Americans settled on one way of getting to the Moon and stuck to it. The parameters of the Apollo program—three men launched on a Saturn V in a Lunar Orbit Rendezvous (LOR) craft—were all set by early 1963. From there it was a steady run for the next six-and-a-half years to the lunar landing, disrupted only by the Apollo 1 fire.

One thing that nearly upset this single-mindedness was the Gemini capsule. It was originally intended as a time-filling experimental craft that would use the gap between the end of Mercury capsule flights on May 15, 1963 and the first planned Apollo test flights. When Lunar Orbit Rendezvous was selected as the Moon mission’s approach, however, McDonnell Aircraft—manufacturer of the Gemini—pointed out that this would mean only two astronauts would go down to the surface. If only two were landing, why not just send two? The Gemini had fourteen days of endurance, after all, and it was only six days to the Moon and back if all went well. McDonnell worked up a way to create a lunar landing craft out of a Gemini that could be sent on a direct-ascent mission to the Moon, the approach that NASA had favoured until the surprising sea change of Spring 1961 that lead to the LOR decision.

In all McDonnell came up with three versions of the craft, dubbed the Lunar Gemini I, II, and III based on how different they were from the orbiting Gemini they were also in the process of building. The Model I was most similar, down to the use of ejector seats for the crew if something went wrong during the initial launch from Cape Canaveral. Its main difference was a modification to the side of the capsule above the left-hand crew member’s head so that there would be a bubble canopy he could look out. Model II was modified to re-enter over water (at the time, the orbital Gemini was being built to come in over land, and so was the Model I Lunar Gemini), with the resulting weight savings allowing for an upgrade to the navigation system and the installation of Apollo’s beefed-up communications system. Model III was most different, including an escape tower to replace the ejector seats, re-entry over water, and a rearrangement of the seats and windows that will be discussed later. All three were also to be equipped with the planned Apollo landing radar.

Besides the other modifications to the capsule, the Lunar Geminis would be built so they could mate to three other pieces, a terminal engine module, a landing gear stage, and a retrograde module. The whole works was then to be attached to the top of a Saturn V which would launch it into Earth orbit. Once in orbit the landing legs would be exposed by ejecting aerodynamic fairings used to protect those fragile structures from the slipstream during ascent.

The retrograde module’s engine would then fire the Lunar Gemini away from Earth towards to Moon, perform mid-course corrections, and insert it into lunar orbit. The module’s final responsibility would be to knock the craft out of lunar orbit into the descent phase, slowing it down until it was only 1800 meters above the surface.

At 1800 meters the retrograde module would have been jettisoned to crash elsewhere on the Moon and the last distance to the ground covered by the terminal landing module’s engine with the capsule and landing stage perched on top.

This touchdown would have been the most hair-raising part of the mission for the Lunar Gemini I and II. As with the regular orbiting Gemini the crew faced towards the nose of the capsule in these two, which is to say they were pointing away from the Moon as the craft backed into a landing. While the co-pilot worked the controls of the lander and watched the Moon in a deployable rear-view mirror, the pilot needed to turn around and observe the lunar surface out of the side of the capsule. That way he could look for a clear area large enough to land in and call out a course to the man working the controls. The plan was to supply him with the aforementioned bubble canopy to give him a 180-degree field of view; if engineering difficulties arose during development the alternative solution was to depressurize the cabin and have the pilot lie prone on his seat back while sticking his head out of the capsule’s opened hatch!

The Lunar Gemini III thankfully proposed rotating the crew seats so that they were side-facing and replaced the windows of the orbital Gemini so that the astronauts could see out to land—much like the Apollo LM was to do.

After touchdown, the astronauts would stay on the Moon for a day, and then the capsule and terminal landing engine would launch for return to Earth while leaving the landing gear behind. This diminished craft would be able to get home directly, without having to stop in lunar orbit like the Apollo program’s LOR.

On arrival at Earth six days after the start of the mission, the Lunar Gemini capsule would detach from the rest of the craft and bring the astronauts home. Models II and III would splashdown with the help of parachutes, while the I model would glide into an airstrip on US soil with the help of landing skids and a Rogallo wing—what we would call today a hang glider, an invention of NASA’s aerospace-focused predecessor NACA. The last remaining change to the Gemini capsule would come into play here: as a direct return from the Moon is faster than a return from low Earth orbit, all three models of the Lunar Gemini would have had a thicker heat shield than their orbital counterpart.

What happened to make it fail: NASA stayed focused and staved off all suggestions that they go with anything other than a three-man, LOR configuration. President Kennedy’s science advisor Jerome Wiesner was the highest-placed advocate of using the Lunar Gemini, but a confrontation with NASA director James Webb eventually eliminated any chance of it by the end of October 1962.

Their refusal stemmed from a couple of good objections to the two-man direct descent approach. The Lunar Gemini had much less redundancy than the Apollo CSM/LM combination, which made its missions considerably chancier. Apollo 13 proved their decision by giving Lovell, Swigert, and Haise the LM to use as a lifeboat, letting them eke out their resources on the way back to home. A Lunar Gemini crew had no such option.

NASA had also studied the Lunar Gemini I and II’s pilot-backwards landing configuration in other contexts and couldn’t come up with a way to do it that satisfied them. Lunar Gemini III was the only arrangement that went for a setup like that used by Apollo, and had to creep up in weight towards the Apollo CSM/LM combination to do it. That meant there was less incentive to move away from their initial plan.

What was necessary for it to succeed: If the Russians had been able to keep Sergei Korolev’s initial lunar landing program going, rather than having it fall into disarray during 1964-65, then the US might have been panicked into switching horses. At the very least US intelligence would have had to conclude that the Soviet Union was on track for a lunar landing in 1967 or ‘68, regardless of whether or not they actually were. This is not entirely unlikely: consider the Uragan space interceptor, which the CIA and industry insiders became convinced the Russians were developing during the 1980s. It apparently never existed.

The Jim Chamberlin-designed Gemini capsule was surprisingly capable, so the Lunar Gemini would probably have worked. The proposal suggested a landing during the first half of 1967, but it would have had to wait until no earlier than 1968 as the craft depended on the Saturn V and that rocket wasn’t ready to go until then—as late as January 1967 one of its stages exploded during testing. The shortcut to the Moon, in other words, would not actually have been that short.

The main difficulty with Lunar Gemini lay with, as mentioned earlier, its lack of redundancy. The crude landing systems of the Gemini I and II would have also produced problems. Consider the famous episode of the last few seconds of Apollo 11’s landing as Neil Armstrong worked feverishly to find a clear landing spot and only just succeeded despite flying a craft more capable than the two lesser Geminis.

So there would have been a Gemini-based lunar landing if NASA had decided to go that way, but the program would have chanced more failures and outright disasters. Mapping it on the Apollo missions has “Gemini 11” aborting at the very last second if NASA has gone with the Gemini I or II, as its pilot can’t find a place to put down. “Gemini 12” succeeds, but then “Gemini 13” is an unmitigated disaster: its astronauts have no place to go after their capsule fails and die while en route to the Moon. Whether or not there’d be a “Gemini 14” through “17” after that is an open question.