STCAEM-CAB: A Mouthful of a Mars Mission (Space Exploration Initiative, Part II)

STCAEM-CAB schematic diagram

A schematic of the STCAEM-CAB Mars space vehicle. The twin heat shields (the scoop-shaped structures) were needed as the craft was too massive to aerobrake in one piece even after the TMIS was jettisoned. The MEV and MTV would separate before the Mars encounter, aerobrake and enter orbit separately, then rendezvous and dock while high above the Red Planet. Public domain image by the author, based on one published in Space Transfer Concepts and Analysis for Exploration Missions, Implementation Plan and Element Description Document (draft final) Volume 2: Cryo/Aerobrake Vehicle. Click for a larger view.

What it was: One of the products of 1991 study by Boeing for a Mars mission vehicle. Technologically it was the most conservative of the possible craft they suggested, relying entirely on cryogenic propulsion, but the trade-off was a hair-raising mission profile including a hard aerobraking maneuver at Mars.

Details: In 1989 the then-President of the United States, George H. W. Bush, put forward a proposal to (among other things) send astronauts to Mars. While NASA had always kept Mars contingency plans up to date since even before Apollo 11, this was one of the few times where it looked for a while like they might actually be able to put their plans into motion. In 1989 they produced a strategic plan known informally as the “90 Day Study” and then set various contractors to work on its different goals.

One of these was “deliver cargo reliably to the surfaces of Moon and Mars, and to get people to these places and back safely”. Boeing was the contractor primarily concerned with this this one, and performed an initial study in 1989 before amplifying it in 1991-92. For Phase 1 of the later study they worked their way through the pros and cons of several different approaches to crewed Mars missions for NASA to choose between, most of which involved novel propulsion systems like nuclear rockets and solar-electric ion engines.

One was more conventional though, closely hewing to NASA’s own baseline for the mission, and was presented first in their Phase 1 final study. All the Mars craft were assigned the clumsy name of the study, Space Transfer Concepts and Analyses for Exploration Missions (STCAEM), and differentiated by their propulsion method. The first craft was accordingly the STCAEM-CAB, the final thee letters standing for “cryogenic/aerobraking”.

The Mars mission was placed firmly in the context of the whole Space Exploration Initiative, not least because the vehicle in question was going to ring in at a whopping 801 tons. No conceivable rocket was going to lift it in one piece, and so the SEI’s space station Freedom was to serve as a base for the in-orbit assembly of the massive ship. A Moon base was also assumed, and served two purposes insofar as Mars was considered: as a test bed for the various technologies, and also a place to put a deliberately isolated habitation module that would simulate a long Mars mission without leaving the immediate vicinity of the Earth-Moon system.

Shuttle-Z in

Another Shuttle-derived launcher (not the Shuttle-Z) charmingly called the “Ninja Turtle” configuration–lifting the STCAEM-CAB’s two aeroshells off Earth and to Freedom. Public domain image from NASA, same source as previous. Click for a larger view.

Using what was called the Shuttle-Z (a variant on the Space Shuttle wherein the orbiter was replaced almost entirely with 87.5 tons of payload, leaving only the main engines, the boosters, and the iconic orange tank), eight trips would be made to Freedom with various components of the ship. After assembly, the STCAEM-CAB would consist of several sections, the largest of which was the Trans-Mars Injection Stage (TMIS) at 545.5 tons. Fuelled with liquid hydrogen and liquid oxygen, the cryogenics referred to in its name, the four-engined TMIS would push the entire craft into a Mars-bound trajectory before being jettisoned. Boeing studied a number of missions that could be flown and came to the conclusion that the relatively less efficient cryogenics propellants would work best when Mars was at opposition, leading to a 580-day mission.

Missions for Mars have often included odd wrinkles in their plans to help cut down the amount of propellant needed to pull them off; for example, the Integrated Program Plan’s mission avoided a circularization burn at Mars, leaving it in an elliptical orbit that made the lander’s descent to the surface start at a higher speed—but better to have to slow down the relatively small MEM than the entire interplanetary craft. In the case of the STCAEM-CAB the trick was unusual enough to warrant mention. For the bulk of the outbound trip, the two other main components of the craft, the Mars Excursion Vehicle (MEV) and the Mars Transfer Vehicle (MTV), would stay docked, with a small transfer tunnel between the two of them. In this configuration it would serve as the habitation for the crew of four astronauts, with the MTV’s crew module being 7.6 meters by 9 meters. This would give each astronaut something on the order 50 cubic meters to live in, with another 50 for everyone to share in the MEV, at least on the way out. With fifty days to go before Mars, however, the two would separate (the crew staying in the MTV, which had the capability of returning them to Earth) so that they could each dive into the Martian atmosphere at closest approach and slow down behind their individual heat shields.The MEV would brake first, 24 hours before the MTV and crew, giving Mission Control a chance to observe Mars close up and decide if it was safe for the second aerobraking maneuver.

Side and front views of the Mars Excursion Vehicle

Side and front views of the MEV after jettisoning its aerobrake and landing on Mars. Public Domain image from NASA, same source as previous. Click here for a larger view.

This approach also had the advantage of making the aerobraking shells smaller, as even done this way they approached the length of a Shuttle Orbiter (30 meters, as opposed to 37.2 meters) and so the shell for a singular craft would have been impossible for a Shuttle-derived stack.

After both had aerobraked and entered orbit, they would dock again, the crew would transfer to the MEV, and then descend to the surface. Several landers were mooted, from one with a 0.5 lift-to-drag ratio (the favored option, pictured at left), one with a 1.1 ratio, and a biconic lander that was going to require a launcher back on Earth that had a diameter of 12 meters(!).

The astronauts would stay on Mars for 30 days, then a subset of the MEV (the third and uppermost of the circles in the MEV image shown, as well as the tankage underneath it) would launch skywards again to dock with the MTV. This would in turn get them back out of Mars orbit and home to Earth, where they would aerobrake again to bleed off some velocity and enter Earth orbit. The crew would finally enter an 3.9 meter wide by 2.7 meter tall Apollo-like capsule for re-entry to somewhere in the ocean. Optionally the MTV would remain in orbit and be refurbished for another journey.

Mars Transfer Vehicle and aeroshell

A closer view of the MTV, which alone would make the journey back from Mars with the crew aboard. The aeroshell would make the trip too, as the craft would aerobrake into Earth orbit too. Public domain image from NASA, same source as previous. Click for a larger view

Boeing scheduled out the launch of the first Mars mission three different ways. One was a “Minimum Program”, intended to do no more than meet the 90 Day Study’s stated goals, one was a “Full Science Program”, while the last was an eyebrow-raising “Industrialization and Settlement Program”. The latter was on Mars by 2009, and saw a permanent Mars base with 24 inhabitants in 2024, some astronauts staying there for years. The science-oriented program made it by late 2010, and saw a permanent lunar base of four (the settlement plan saw 30!) but only a periodically inhabited Mars base of six astronauts. The minimum options saw a first Mars landing, by coincidence, in 2016. It had neither permanent Mars or Moon base. As for the cost of each, Boeing includes various graphs but only gives one number, for the Industrial and Settlement Program: an eye-watering $100 billion from 2001 to 2036, with a peak of $19 billion in 2020.

What happened to make it fail: Well, “$100 billion…with a peak of $19 billion” for a start. While the Bush Administration was obviously looking for their own version of a “Kennedy Moment” when they announced the Space Exploration Initiative, they were not all that keen on actually paying for it. Couple that with extreme hostility from Congress anyway, and the SEI’s ultimate goal of Mars mission was in trouble right from the start. Likewise NASA blew it by proposing grandiose plans like an 800-ton Mars ship, the full space station Freedom, and a permanent lunar base, to the point that the backlash led to the “faster, better, cheaper” era under Dan Goldin (which had its own problems, but that’s another story). Boeing even spent some pages in Phase 1 trying to determine returns on investment and the like, with some of their anxiety at the cost coming through in their prose. This includes an unflattering comparison to the development of the Alaskan oil pipeline and the investment in supertankers during the closure of the Suez Canal from 1967-75.

As far as the STCAEM-CAB in particular was concerned, it also suffered from being “good under most circumstances but never the best”. Boeing preferred the Nuclear Thermal Rocket variation, and focused on that going forward from Phase 1 of the study, even though Goldin had been NASA administrator for a year and a half by the time their final work on the project was completed. The NTR variant was certainly not going to go ahead thanks to NASA’s new focus, and the CAB had already fallen by the wayside.

Ultimately, though, this mission suffers from the same problem as the Integrated Program Plan’s Mars Mission from the early 70s. It existed down near a long line of large programs, few of which actually happened. You need to join back up several links in a chain to get to the launch of this spacecraft. Ultimately, quite a few things would need to change for STCAEM-CAB to make its trip, making it quite unlikely under any circumstances.


Space Transfer Concepts and Analysis for Exploration Missions, Implementation Plan and Element Description Document (draft final) Volume 2: Cryo/Aerobrake Vehicle, Gordon.R. Woodcock. Boeing Aerospace and Electronics. Huntsville, Alabama. 1992.

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 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.

M-19 “Gurkolyot”: Grab the Problem by the Throat, Not the Tail

Myasishchev M-19 Gurkolyot schematic

A schematic of the M-19. Despite its great width and length, it was to be very flat, and mass only 500 tonnes. Image by the author, released to the public domain. Click for a larger view.

What it was: The Ministry of Aviation’s candidate for a Soviet shuttle, an apparent attempt to wrest control of the Soviet crewed space program away from the Ministry of General Machine Building. It was a runway-launched, single-stage-to-orbit spaceplane using a hydrogen propellant-based nuclear engine, designed by the Myasischev bureau that had previously worked on the VKA-23.

Details: After the first Myasishchev bureau was dissolved 1960 and many of its people moved to OKB-52, Vladimir Myasishchev didn’t lose his interest in spaceplanes. He became head of TsAGI, the Soviet experimental aviation bureau, then in 1967 was allowed to refound his own bureau, at which point he picked up from where he left off. A few years later the Soviet Shuttle project began, and Myasishchev was in the large camp of designers who were skeptical of the American design which slowly became the favorite behind the Iron Curtain.

Many years earlier, responsibility for the development of rockets in the USSR had been disavowed by the Ministry of Aviation and fallen instead to the Artillery wing of the Red Army. When ballistic missiles and rockets became the glamorous thing in the late 50s the aviation types came to regret their decision and repeatedly tried to barge into the business—Vladimir Chelomei came from the aerospace side of things, for example. Now that the USSR was in the large, reusable orbiter business, the Ministry of Aviation chose Myasishchev’s new bureau as their new champion and set him to work.

What the V. M. Myasishchev Experimental Design Bureau then proposed was a series of three craft, with several variations on each type, that would start with a high-speed test-bed and end with an orbital spaceplane. The middle craft was a reasonable knock-off of the NASA Shuttle, but the first and third were a radical alternative program. Back in the 1960s an engineer at NII-1 (“Institute of Jet Aviation-1”), Oleg Gurko, had come up with a novel concept for a SSTO, based around a nuclear reactor, the details of which we’ll explore shortly.

His suggestion got nowhere in the 60s despite his approaching both Myasishchev and Mikoyan, representing the Aviation Ministry for which he worked. Once work began on the Soviet shuttle, however, the Aviation Ministry’s interest picked up and the Myasishchev bureau was told to work on a proposal based on Gurko’s idea. Myasishchev himself realized that this SSTO would be a massive leap based that would take a long time to develop, but he was uneasy with merely copying the American shuttle as that kind of a project would only be completed several years after the United States was flying (as indeed was the case, with STS-1 occurring in spring 1981 and Buran’s one, crewless flight being in November 1988). If his country was going to be behind anyway, why not work on a project that would at least offer the opportunity to leap ahead during the delay? He reportedly summed up his approach as “Grab the problem by the throat and not the tail, or else you will always have the tail”.

The breadth of Myasishchev’s ambition can be measured by understanding that the first plane in his program was not just a testing ground but, in order to bring the Ministry of Aviation on-side, was intended to double as an operational Mach 6 bomber flying at 30 kilometers up, twice as fast and fifty percent higher than the XB-70. The final plane was considerably more capable than even that.

Weighing in at 500 tonnes with fuel, the M-19 was a very flat, 69-meter long triangular wedge with two small sets of wings, one at the tail and one as canards near the nose. Launching horizontally from a runway, the M-19’s trip to orbit would begin with twin turbofan jet engines burning liquid hydrogen. After getting up to Mach 4, the plane would switch over to scramjet engines, also burning hydrogen. In both cases, though, the engines had Gurko’s idea behind them for a little extra kick.

The M-19 would have had a nuclear rocket engine that would take over in turn once the scramjet pushed the plane to Mach 16 and out of the appreciable atmosphere around 50 kilometers high. As the reactor was just sitting there during the turbojets’ and scramjets’ operation, Gurko reasoned, why not use it to superheat their exhaust to increase thrust? The potential increase in efficiency was considerable, and as the nuclear rocket (already more efficient than chemical rockets) would only be used for the final leg, the low inherent fuel use of the air-fed turbo- and scramjets gave the M-19 a tremendous payload fraction: the 500-tonne fully fueled plane was projected to lift 40 tonnes to LEO in its 15m × 4m cargo bay, which compares favorably to even staged rockets. Consider the Space Shuttle at 2040 tonnes and 28 tonnes of payload, or the Saturn V at 3038 tonnes and 118 tonnes of payload. To move whatever was stored in it, the bay was to be equipped with a manipulator unit, and an airlock from the crew compartment allowed EVA. Behind the bay was a large LH2 tank and, it should be made clear, no oxidizer tank. The rocket would run on raw hydrogen, while the two different types of jet would use the air as their source of oxygen.

After completing its mission in orbit, the M-19 would then fly back home, using the same propulsion systems in reverse order to come into a powered landing at an airstrip somewhere in the USSR, with an astonishing cross-range capability of 4500 kilometers. This completely plane-like return was of considerable interest to Soviet space planners for other reasons too, as it meant that the M-19 would reduce search and retrieval costs to nil as compared to capsules unless there was an emergency. Under those circumstances the cabin was to be entirely ejectable, serving as a survival capsule for the three to seven cosmonauts that might be on-board..

That the M-19 was perfectly capable of flying as an airplane in the lower atmosphere made it much more flexible too, as it could be moved to a different launch site relatively easily. And, as it didn’t drop stages on the way to orbit, it could be launched in any direction without worrying about what was downrange—a problem that’s particularly difficult for the USSR and Russia, and has led the latter to build its newest cosmodrome in the remote Amur region by the Pacific Ocean.

Even in space the M-19 was unprecedentedly flexible, able to make repeated orbital plane changes by diving into the upper atmosphere and maneuvering aerodynamically. Whether performing an inclination change or coming down to land, the M-19 was protected by reinforced carbon-carbon (like the Space Shuttle’s leading wing edges) and ceramic heat tiles.

The rocket for the M-19 was to be be built by the Kuznetsov design bureau, also the builders of the conventional engines for the N1, and would have been the first operational nuclear rocket in the USSR (and indeed the world).

Testing beforehand would involve several flying test beds to develop hydrogen-burning engines and scramjets, drop test articles, and the aforementioned hypersonic test vehicle/bomber. Though Gurko himself did not work for the organization assigned to build the M-19 he consulted on it, and the M-19 gained the nickname “Gurkolyot” (“Gurkoplane”). If given the immediate go ahead, the Myasishchev Bureau predicted that the final craft would be ready for flight in 1987 or ’88.

What happened to make it fail: First, Myasishchev’s bureau was absorbed again in 1976, this time into NPO Molniya, newly founded to make the Buran orbiter. The Soviet leadership had placed their bet on a close copy of the US’ Shuttle.

Second, even Myasishchev called the M-19 his “swan song”, and that his ambition was to set the USSR on the right course, not see it through. He was in his seventies even before preliminary work began on the spaceplane, and his death in 1978 took away the program’s biggest voice. While some testing of a jet engine running on liquid hydrogen took place in 1988 (in the modified Tu-155 jet), and the first Soviet scramjet was tested on top of an S-200 missile in 1991, by 1980 the M-19 had receded into the future as a possible successor to Buran, rather than a competitor.

Then the USSR came apart from 1989-91, and the future of the Soviet space program was forced into radically different channels.

What was necessary for it to succeed: This is an awfully tough one to assess, as the M-19 is by some distance the most technologically sophisticated spacecraft we’ve looked at. It was based around so many novel approaches (a nuclear rocket engine, a scramjet, preheating the jets’ air, SSTO, and so on) that it seems impossible even with current aerospace technology. Scramjets and SSTO in particular are two things which seem to endlessly recede into the future as we come to understand how difficult they are.

However, Myasishchev and his bureau acknowledged that it was a radical departure, that it would take a long time to develop, and that nevertheless they thought it could be done—and they were some of the best aerospace engineers in the USSR, if not the world. Who am I to say they were wrong?

Even so, it does seem like they were. The problem was not an engineering one (even if I’m skeptical that anything like this could fly before the mid-21st century), but rather an economic one. The M-19 needed time, and the USSR had surprisingly little left. How to fix the economic mistake on which that country was based? There are convincing arguments that it could not be fixed, and that at best the Soviet Union could have lasted only another decade or two past 1991 while becoming increasingly pauperized year-on-year—hardly the best environment for cutting-edge aerospace research. The M-19 simply could not fit into the time remaining, even with any reasonable stretch in the USSR’s lifespan.

Samoletoya EMZ in V. M. Myasishcheva, A.A. Bryk, K.G. Oudalov, A.V. Arkhipov, V.I. Pogodin and B.L. Puntus.

Energia-Buran: The Soviet Space Shuttle. Bart Hendricx and Bert Vis.

The Mars Excursion Module: One More Small Step (Integrated Program Plan, Part IV)

Mars Excursion Module 1967

The Mars Excursion Module, as shown in 1967’s “Definition of Experimental Tests for a Manned Mars Excursion Module, Volume IV”. By 1969 it would evolve to have a truncated rather than rounded nose, and the base section was larger to notionally support storing a rover. This view affords an excellent look at the central ascent vehicle and its tanks, which would leave the rest behind. Public Domain image via NASA. Click for a larger view.

What it was: The last piece of the Integrated Program Plan’s mission to land astronauts on Mars in the 1980s. First proposed in 1966 (though with a similar, smaller craft being advocated by Philip Bono in 1964), in 1969 it was presented by Wernher von Braun to the Space Task Group and adopted as part of NASA’s proposal for the post-Apollo focus of that agency. Though not developed by him, it represented the culmination of his lifelong dream to visit Mars vicariously through the people he would be instrumental in sending.

Details: In a world where NASA’s Integrated Program Plan of 1969 went forward, you might be an astronaut on the first mission to mars. After getting to orbit on board the Space Shuttle (likely the “DC-10” of Max Faget‘s design, or similar), you’d board a Nuclear Shuttle-driven


MEM schematic view, 1969, showing the standing pilots and the tunnel to the lab and living area in the lower section. Public domain image from NASA. Click for a larger view.

interplanetary ship gingerly fuelled by personnel in Space Tugs. The journey would be a long one: hundreds of days, and possibly including a flyby of Venus, the exact duration depending on the year when the mission got underway. Eventually you’d get to your destination, though, and assuming all was well your ship would settled into an elongated orbit around the Red Planet. Half of you would stay aboard, while the remaining six astronauts (hopefully including you) would get to go down to the surface. To accomplish that, you’d use the Mars Excursion Module (MEM).

NASA studied a variety of craft that might make this final leg of the journey, but the MEM as pictured in 1969 first made an appearance in a study done at the Marshall Space Flight Center in June of 1966. A year previous, Mariner IV had shown that NASA’s previous best estimate of Mars’ atmospheric density, which had been about 25 millibars, or about 2.5% of Earth’s atmosphere, was much lower than expected at just 6 millibars. Previous designs were useless, relying as they did on lifting bodies and parachutes that would get some “bite” from the air on the way down. The Marshall suggested shape, resembling an oversized Apollo capsule, was the first to deal with the reality of the situation: after entering the Martian atmosphere, even the MEM’s capsule-shaped body would only slow to a terminal velocity of 900 m/s and then carry on at that rate until hitting the ground. As this is just a little over 2000 miles per hour, it would bring the “terminal” to the fore if nothing else were done.

By November 1967 the details had been worked out after the problem was handed off to North American Rockwell. Their MEM was now recognizably the craft pitched by von Braun in 1969, though different in carrying four astronauts. During the descent the crew would be in the command module which took up the point of the MEM’s conical shape, while the lower deck’s laboratory, living quarters, and external airlock would be reached through an internal airlock and tunnel. The capsule was 30 feet in diameter at its base (9.1 meters) and 29 feet tall (8.8 meters). At re-entry time it would weigh 46.1 tonnes. Altogether this made it approximately the same size as the full Apollo CSM if the latter craft’s service module had continued the slope of the capsule on top of it instead of following parallel lines down to the engine. The contents of the extra volume enclosed made for a 14-tonne difference in mass, though, and later iterations of the MEM upped its base to 32 feet, the same diameter as a Saturn V, with a corresponding increase in weight.

The MEM in the context of the larger Mars Expedition craft.

The MEM in the context of the larger Mars Expedition craft. Public Domain image from 1968’s “Integrated Manned Interplanetary Spacecraft Definition, Volume IV”, via NASA.

After departing the Mars Expedition ship, the MEM would use a solid retrorocket to leave orbit and a liquid fuelled one to land, parachutes being all but useless in the thin air. On the plus side NAR’s engineers noted that Mars’ pitiful atmosphere meant that heat shields could be a lot lighter than those needed for re-entry on Earth. The one on the underside would a titanium honeycomb covered with ablating AVCOAT, also used by the Apollo capsule as well as with the Orion MPCV. The ones on the upper slopes of the MEM, made of titanium or L605 cobalt alloy depending on the heat it would endure, could be jettisoned to lose weight partway through the trip down to the ground. Daringly, two of the crew would remain standing to pilot the craft (probably supported by a harness when under heavy deceleration loads), and get the MEM landed on its six-legged landing gear. If they had to, they could hover the MEM above the surface for as much as two minutes.

Once down, the crew of the MEM would begin a 30-day stay on Mars. On the surface the MEM would be powered by two fuel cells in the mission module. An S band microwave link would be used for a TV signal back to Earth, as well as telemetry and voice communications, while a VHF link would be used for communications back to the orbiter as well as linking astronauts on the surface to the capsule.

Various configurations of the MEM as it goes through its mission

The many faces of the NAR MEM, from Mars deorbit, lower left, to ascent and rendezvous with orbiter, lower right. Public domain image via NASA, same source as previous. Click for a larger view.

When the mission was over, the toroidal mission module and the landing gear of the MEM would be discarded. Getting back off Mars was arguably the most difficult part of the mission, as North American Rockwell found that even LOX and LH2 was not powerful enough to do the job. Instead they settled on FLOX (70% liquid oxygen and 30% liquid fluorine) as the oxidizer and methane as the fuel, with careful staging of the ascent module’s tanks to minimize mass during the flight, in order to make it back to orbit. Rather than have to deal with two different sets of propellants, the landing engine would have burned the same. This is a somewhat alarming choice, both because the words “liquid fluorine” are always alarming and because FLOX and methane have never been used together in an operational rocket engine (Atlas engines had tested with FLOX and kerosene at least, in the years prior to 1967). The MEM’s reaction thrusters used an odd combination too, chlorine pentafluoride as an oxidixer and hydrazine.

North American Rockwell declared that they could build the MEM given seven years from 1971 to 1978, including heat shield tests from orbit, two manned test flights, and a 242-day “soak” in LEO vacuum to simulate the transit to Mars, with an actual Mars mission sometime from 1981 onward. Hardware development costs would be in the range of US$3.1 to US$5.0 billion.

What happened to make it fail: We’ve discussed the Mars Expedition as a whole previously, and the answer is still the same. Richard Nixon was uninterested in manned space programs and was only willing to support the Space Shuttle for fear of being remembered as the man who ended the Space Age. It’s easy to paint Nixon as the villain here, but he was a reflection of the reality that was incoming 1970s: the economy was sputtering, Vietnam was costing a fortune, a majority of the American public didn’t care, and Congress was deeply hostile to a Mars mission. A crewed trip to Mars was pushed off nebulously to the year 2000, safely a minimum of five presidential administrations away. Even slight familiarity with American politics understands this to be the political equivalent of your mother saying “We’ll see” when you asked her for a dog.

What was necessary for it to succeed: The IPP’s Mars landing was the end point of a large number of complex programs. In rough order these were: a Space Shuttle based on a winged orbiter, a LEO Space Station, small Space Tugs, orbiting propellant depots, Reusable Nuclear Shuttles, a Moon base, and possibly an Orbiting Lunar Station. By 1972 NASA’s future was busted down to the Shuttle, and as of 2016 they’re all the way up to step two.

The world where the Integrated Program Plan was followed is a very different one from ours, so it’s difficult to say what could possibly have brought the MEM to fruition. The best-known attempt is SF author Stephen Baxter’s misanthropic novel Voyage, but his suggested alternate outcome of the Kennedy Assassination isn’t sufficiently different to overcome the economic and social tides that sunk the IPP. Early collapse of the USSR in the late 1960s? Election of Gerard O’Neill as dark-horse, third-party President of the United States in 1976? Wernher von Braun finds a magic monkey paw? Your guess is as good as mine.

Technically, the MEM was sound. It was just about everything else outside its conical shell that went awry.

Other Fun Stuff

A picture of a MEM on the surface of Mars by artist Tom Peters

A neat shot of the heat shield jettison on a variant MEM using a ballute to maintain attitude, also by Tom Peters.


“An Initial Concept of a Manned Mars Excursion Vehicle for a Tenuous Mars Atmosphere”, Gordon R. Woodcock. NASA, Marshall Spaceflight Center. 1966.

“Definition of Experimental Tests for a Manned Mars Excursion Module. Final Report, Volume IV—Briefing”, Geoffrey S. Canetti. North American Rockwell. 1967.

“Integrated Manned Interplanetary Spacecraft Definition, Volume IV, System Definition”, Anonymous. Boeing. 1968.

The R-56: “Yangel Works for Us”

Thre possible arrangements of the R-56 rocket

Three possible arrangements of the R-56 rocket. The one on the right is the “4-4-1” module arrangement initially favoured, while the one at centre is close to the monoblock version finally settled on (it is missing the flared skirt necessary to house all of its engines). Original source unknown.

What it was: A four-stage rocket proposed by OKB-586 in the early 60s. It was aimed at the Moon, despite having a payload of 40 to 50 tonnes, making it much lighter than any of the Saturn V, N1, or Energia. It still would have lifted more than any rocket being flown in 2016.

Details: In February 1962 Nikita Khrushchev organized a meeting of the USSR’s Defense Council with the main missile designers in the Soviet Union at his dacha in Pitsunda (a resort town in the Georgian SSR) for the purpose of rationalizing their missile and space programs. The main players were Sergei Korolev with OKB-1 and Vladimir Chelomei with OKB-52, but a third invitee was Mikhail Yangel, the head of OKB-586.

While Korolev had surged to the head of the Soviet space program post-1957 and initially stood first in ICBM development, all based on variations of the R-7 rocket, by 1962 he had lost leadership in the latter to Yangel. The previous November his R-16 had become operational, and its use of storable propellants made it more militarily desirable than the liquid oxygen-using R-9 that was OKB-1’s response. Though the R-9 could be fuelled and fired in roughly the same amount of time, the feeling among almost everyone but Korolev was that storable fuels were the way forward when it came to developing a nuclear strike capability that could be used with little notice.

Meanwhile a fourth man and his bureau was working behind the scenes. Valentin Glushko had been trying to make large engines that used LOX for oxidizer. The tremendous vibration in his prototypes led to combustion instabilities that caused, as they say, “rapid disassembly”. Convinced that the problem could not be cracked, he had come around to storable propellants, and this had become a problem between him and Korolev. OKB-1 was pushing ahead with the N1 and, while storables were considered for that project, the writing was on the wall: Korolev wanted LOX and kerosene, or LOX and liquid hydrogen. A few years previous Glushko could have pushed back effectively, but Khrushchev had been downsizing the USSR’s military aviation efforts, and underemployed bomber-designing bureaus had been growing new departments devoted to rockets—the N1 would end up flying, for sadly abbreviated distances, using engines developed by Nikolai Kuznetsov’s OKB-276.

Glushko hedged his bets by teaming up with Chelomei on the UR-700 and the UR-500, which were aimed at the 70+ and 20-tonne payload targets set by Khrushchev. The former was to be a super-heavy interplanetary space launcher and the latter was a combination heavy LEO space launcher and ICBM. The smaller of the two figures was apparently selected due to the test of the RDS-220 hydrogen bomb (better known by the name given to it in the West, the “Tsar Bomba”) a few months earlier. This 100-megaton demonstrator had come in at just under 27 tonnes, and it was thought that refined versions with about half the yield would come in several tonnes less than that.

These two rockets were OKB-52’s proposal to the Defense Council meeting. OKB-1 countered with the already-underway N1 and, for the smaller launcher, the N2, which was essentially the N1 with its tetchy first stage removed. Seemingly out of worry that OKB-1 would still prevail, Glushko had arranged for another card in his hand—Yangel.

A relative newcomer to the space side of missile work, Yangel had earned a reputation as someone who listened to the military with the R-12 and R-16 missiles, in contrast with Chelomei and Korolev, who were viewed to varying extents as prima donnas, or at least less than entirely focused on military applications of their rockets. Yangel parleyed this approval into an unmanned satellite launch that was to go ahead the next month: Kosmos-1, the very first mission of the soon-to-be-ubiquitous Kosmos program that represented the large majority of Soviet launches from 1961 until the fall of the USSR. Yangel was interested in extending his nascent space work into manned programs, at least to the extent of designing the rockets for them, and he and Glushko had initially worked on creating a rocket, the RK-100, using the same storable propellant engines that OKB-52 was designing for Chelomei. If Glushko failed to unseat Korolev through Chelomei, then teaming with Yangel would give him another bite at the apple.

The RK-100 was a clustered rocket and Yangel was reportedly displeased with the particular design that his OKB-586 came up with. In any case the first comprehensive space policy statement by the Soviet government, made in 1960, ruled out any possibility of it going forward. At this point the focus shifted to another Yangel-Glushko collaboration. Once again a clustered approach was used. Working on the base of a booster “module” resembling the smaller rockets with which OKB-586 had had success, this new rocket consisted of four modules on the first stage, four on the second, and then a core booster being the third and final stage. This proposal was dubbed the R-56, and Yangel brought it and another design, the R-36, to the conference.

What he didn’t do was go head-to-head with Korolev and Chelomei. As initially conceived the R-56 would slot into the space between the 20 and 70 tonne launchers, lifting 30-40 tonnes or so, while the R-36 was much smaller than any of the other rockets mentioned, aiming for a sweet spot in automated satellite launches around 1-2 tonnes to LEO.

The meeting did not go well for Yangel’s crewed space ambitions as by April a turgidly named decree called “On the most important projects of intercontinental ballistic and global missiles and carriers of space objects” was issued. It instructed the bureaus involved to go for the N1 as a space vehicle, the UR500 (which would eventually become the Proton) as both a space vehicle and ICBM, and the R-36 solely as a missile—though it too would become a satellite launcher one day, the Tsyklon. However, in the few weeks of space between the original meeting and the decision, Glushko began lobbying the Strategic Rocket Forces and Dmitri Ustinov about not only the “4-4-1” module version but one with a “7-6-1” configuration that he said would lift 70 tonnes—obviously the direct challenge to the N1 and UR-700 that Yangel did not make himself. His efforts paid off. While not authorizing the R-56, OKB-586 were given permission to at least study the “4-4-1” configuration.

A year later, in 1963, the order for the R-56 was revised to specify that it should lift 40 tonnes to LEO. While Yangel’s bureau studied modular rockets that could handle this new requirement, for all intents and purposes they went back to the drawing board and settled on a completely different approach: a four-stage “monoblock” arrangement, to use the Russian term. This is the familiar, boosterless approach where each stage is singular and is merely put on top of another singular stage—the Saturn V being the most famous example of this. The first two stages of this R-56 did the heavy work of getting a payload into orbit, while the third was used to get it to geosynchronous orbit, if that was the intended destination. The optional fourth stage would be for the extra push needed on lunar and planetary missions.

The first stage would be outfitted with sixteen RD-253 engines, the same one to be used on the UR-500 (which had six) and which was ready to fly in July, 1965. This cluster of engines was actually wider than the intended 6.5-meter diameter of the first stage, so it was installed with a short skirt which enclosed 8.2 meters at the base. The second stage had one of the same engine, equipped with a modified bell tuned for operations in vacuum, as well as a small steering engine that produced 15% of that stage’s total thrust. The third stage tapered from 6.5 meters down to 4 meters in diameter, which was the gauge of the rocket up to the top of its 67.8 meter tall stack. Loaded up with Glushko and Yangel’s preferred N2O4 and UDMH, it would weigh in at 1421 tonnes. Compare this with the Saturn V’s 110.6 meters and 2970 tonnes, or the Energia’s 2270 tonnes (not counting Buran) and 58.765 meters. While not in their class, this new R-56 was heading in their direction. If it had been built to spec, it would have been able to lift a little over 46 tonnes to a 200-kilometer orbit when launched from Baikonur, or 12.6 tonnes to the Moon.

What happened to make it fail: All the meetings and decrees regarding the Soviet space program failed to straighten out the USSR’s lunar program. At the end of 1963, multiple boosters and spacecraft were still in play, and the Soviet leadership had still not even formally authorized an attempt by their country at the Moon landing. In an effort to finally settle things, in March 1964 Yangel proposed to the Military-Industrial Commission that Soviet space efforts be split three ways: OKB-1 would work on the lunar spacecraft, Chelomei’s group would get the automated probes to the Moon and the planets, and he would build the rockets.

The Commission turned him down, reasoning that too much work had been put into the N1 already for it to be replaced now. There was reportedly also some discomfort with the fact that the R-56 would need two launches (at minimum) for a Moon mission, which implied a docking in orbit at a time when the first Soviet docking was more than three years in the future.

Yangel then petitioned in succession both Dmitri Ustinov and Leonid Brezhnev (seven months from becoming leader of the USSR, but then in charge of the space program and a native of Dnepropetrovsk where OKB-586 was based). Neither would back him, and the R-56 was formally cancelled by another decree, “On speeding up work on the N1 complex”, that was made on June 19, 1964.

After the Moon program was finally approved in August of 1964, Yangel’s bureau was assigned to work on the terminal descent/ascent engine for the LK-1, the program’s lunar lander. It thus had the distinction of being one of the few pieces of the Soviet Moon landing craft to make it into space, as it was tested successfully in orbit three times in 1970-71.

What was necessary for it to succeed: The main problem with the R-56 program seems to have been Yangel’s willingness to let go, as opposed to the on-rushing bulls that were Korolev and Chelomei. If he’d been willing to push harder or been a little luckier during the 1962 meeting he might have won the day—Sergei Khrushchev specifically says that he thinks his father would have picked the R-56 at that time if Yangel had presented first rather than last.

On the other hand, even down to 2016 no-one has ever built a rocket with a payload capacity in the 40-50 tonne range (SpaceX’s under-development Falcon Heavy is closest, at 54.4 tonnes). Smaller is fine for almost all launches, and crewed missions absolutely require more if going to the Moon or beyond (barring the construction of a larger craft using multiple launches, which has also never been done). There’s good reason to believe that even if it had flown, the R-56 might have ended up not being good for much of anything.


“Heavy Launch Vehicles of the Yangel Design Bureau, Part 1”, Bart Hendrickx. Journal of the British Interplanetary Society, vol. 63, Supplement 2. 2010

“Heavy Launch Vehicles of the Yangel Design Bureau, Part 2”, Bart Hendrickx. Journal of the British Interplanetary Society, vol. 64 Supplement 1. 2011.

Nikita Khrushchev and the Creation of a Superpower, Sergei Khrushchev. Penn State University Press. 2001.

Sidebar: The Intercontinental Ballistic Vehicle

Intercontinental Ballistic Vehicle schematic

A schematic of the IBV as printed in LIFE Magazine, March 7, 1955 via Google Books. Artist unknown, possibly Michael Ramus. © Time, Inc. Click for a larger view.

We’ve previously discussed Eugen Sänger and Irene Bredt’s wildly ambitious Silbervogel, a suborbital spaceplane that they worked on in Germany prior to the end of WWII. Mentioned in passing at the time was Stalin’s interest in it after the war, and Mstislav Keldysh’s unsuccessful attempt to scale back its necessary technological innovations so that the USSR could build something similar. What we didn’t look at at the time was the high-water mark of Sänger and Bredt’s craft in the United States.

Their core design paper was translated into English in 1946 as A Rocket Drive for Long Range Bombers (and is readily available today on the web), but otherwise there was not a lot of interest in it in the West. Sänger and Bredt lived in France for several years after 1945, having secured positions there, but worked on other projects.

Grigori Tokaev/Grigori Tokaty

Grigori Tokaty (to use his preferred name) in 2001, more than a half-century after revealing Stalin’s interest in rocket bombers to the West. Public Domain image via Wikimedia Commons.

Then, in November 1947, Soviet rocket engineer Grigori Tokaev defected to the United Kingdom. According to him, Stalin had become aware of the work on Silbervogel, and assigned the trio of Tokaev, Stalin’s son Vasily, and future head of the KGB Ivan Serov to the case. The Germans scientists were to be convinced to come to the USSR (Tokaev’s preferred approach) or kidnapped (Serov, naturally, for a man nicknamed “The Butcher”). The pursuers were unaware that the two they sought were no longer in Germany, though, and none of the three trusted any of the others, so nothing came of it. In 1949, Tokaev became an author under the Ossetian version of his last name, Tokaty, writing several popular articles about Soviet ambitions with long-distance airpower and other then-advanced weapons, then getting into an extended war of words about them with the hard Left in the UK.

Into this furor stepped John Earley and Garret Underhill in LIFE’s March 7th, 1955 issue, with an article named “From Continent to Continent”. Based on their own understanding of Sänger and Bredt’s work, as well as Tokaty’s story, they sounded the alarm. Keldysh’s aforementioned failure would not become known outside the USSR for many years, and the two LIFE authors felt that instead the USSR was probably working on the project with alacrity.

Their particular iteration of Silbervogel was closely based on the German design with a few variations suggesting that the authors didn’t really know what they were doing (for example, changing its trapezoidal cross-section to a circular one, which would be hell on re-entry). Launched from a rocket-propelled sled it would get up to a speed of 10,600 MPH (17,000 km/h) and 113 miles (182 kilometers) in height, then skip/glide its way around much of the planet. On a sortie from the Soviet Union, the authors thought that this craft would fly over the Arctic, bomb the United States, and then make a landing in the Pacific “for recovery by submarine”—which seems a bit optimistic but may reflect the idea in Sänger and Bredt’s original paper that WWII German Silbervogels could land in the Japanese Mariana Islands.

Really, “From Continent to Continent” is a bit of a head-scratcher until one realizes that it’s not a proposal, but is instead largely a con job, presumably written for the purpose of stirring up trouble and increasing circulation. For example, as can be deduced from the previous paragraph, the authors took the particular tack of describing how the IBV would be used to attack the United States even though the ostensible purpose of their article was to suggest that the US build one themselves, by their estimate in three years for a mere $23 million. Its mission as an American craft was left unstated, and was surely not the exact inverse of their favoured blood-curdling scenario of a Soviet attack.

There’s also the way the article’s authors are described: “[John] Earley, a rocket designer, and [Garrett] Underhill, a former Army officer who is an expert in Russian weapons” looks crafted to make unsuspecting readers think that they were insider sources for another, different LIFE correspondent. They’re almost certainly the authors of the piece themselves, even though it’s unbylined. I can find no other references to John Earley, but Garrett Underhill was the military affairs editor for LIFE in 1955 and had been out of the military intelligence business for most of a decade. Incidentally, if you’ve heard of Underhill, it’s as a minor figure in JFK conspiracy circles who committed suicide in 1964.

Taken as a whole, the IBV is more interesting as a snapshot of its time than it is as a quite ill-founded proposal. In a way it’s the flip side of the contemporary Moonship of Wernher von Braun: it was a popularization of the future military use of space, as opposed to its scientific exploration. The major difference between them is that von Braun’s fundamental vision was the one that took hold, making the way it was laid out in Collier’s and by Disney into well-known classics. Meanwhile the IBV has long since dropped into obscurity.

LKS: The Buran Alternative

LKS spaceplane on Proton rocket

An LKS orbiter atop its Proton launcher at the launch gantry. Original source and copyright status unknown, but pre-dating 2004. Note the folded wings: most sources do not mention this feature, with the implication that LKS’s wings were fixed, but the LKS is sufficiently badly documented that even this basic question is not definitively answered.

What it was: A small, 20-tonne spaceplane intended for launch on top of a Proton rocket. From 1979 to 1983, OKB-52 touted it as an alternative to the Energia/Buran shuttle.

Details: Continuing the parallel, military-oriented space program of OKB-52 (previous entries so far being the LK-700, Almaz, and the TKS), we come to the LKS. In late 1973 the Soviet government decided to respond to the prior year’s announcement by the United States that they would be building the Space Shuttle. OKB-1 was given the task of examining a large spaceplane in the same class as the Americans’, while Mikoyan and OKB-52 were ordered to look at something in the 20-tonne range.

The convulsions of 1974-75 pointed NPO Energiya, the former OKB-1, in the direction of responding to the American Space Shuttle with a quite-close copy (though not before sketching out the MTKVP), and eventually the “Buran Decision” was made in its favour in 1976.

Governmental decision or not, the ever-contrary Vladimir Chelomei and OKB-52 carried on with their own spaceplane from 1976-79 to address what they saw as Buran’s deficiencies: it was smaller, lighter, would be quicker and cheaper to develop and, in their opinion, be almost as capable. They called their two-cosmonaut craft the LKS (“Legkiy Kosmicheskiy Samolet”), meaning “Light Space Plane”.

Inevitably the LKS was to be put on top of OKB-52’s workhorse, a Proton rocket—though not man-rated, the intention was to do so for also launching the TKS anyway. This dictated much about the orbiter, starting with its mass. The Proton-K used until recently could lift just shy of 20 tonnes to low-Earth orbit, which is a bit less than a quarter of either a Shuttle or Buran orbiter carrying a full payload. So while the LKS had a similar shape to its larger cousins by design, its launch mass was only 19,950 kilograms, with a length of 18.75 meters and payload of 4 tonnes (compare with 37.24 meters and 27.5 tonnes for an American shuttle). This is, not at all coincidentally, close in mass to the TKS, and the two can be thought of flip-sides to one another as OKB-52 tried to be everything to everyone while also integrating their proposals into the larger space effort envisioned by Chelomei.

The LKS orbiter diverged from the larger shuttles in a number of other notable ways too, even after being redesigned to be essentially a half-scale version of the US Shuttle Orbiter (earlier incarnations had twin tail fins and wings with a straight leading edge). Its in-orbit engines were to burn N2O4 and UDMH, like every other motor of note proposed for use by OKB-52. Its landing gear was peculiar too, with a steerable wheel up front and landing skids under the wings. Chelomei also proposed to use a renewable ablative re-entry shield rather than the ceramic tiles common to the American and Buran orbiters. As aerodynamically similar as it was, though, it still had the same ~2000 kilometer cross-range capability and would glide in to land at a similar speed (reportedly 300 km/h, a bit slower than the Shuttle’s 350).

OKB-52 had made a full-sized mockup of the orbiter by 1981, then Chelomei pounced during the period of Soviet alarm following Ronald Reagan’s “Star Wars” speech in March 1983. In a letter written directly to Leonid Brezhnev he suggested that the LKS could be used to quickly and cheaply deploy counter-missile lasers into orbit. Sources differ on whether this was as satellites in the payload bay, or if he meant a fleet of unmanned LKSes carrying the lasers directly—but most lean towards the latter.

What happened to make it fail: Having raised the profile of the LKS as a counter to SDI, Chelomei’s efforts came under the scrutiny of the Soviet military. A state commission was convened in September of 1983, headed by the deputy minister of defense Vitali Shabanov. It eventually came to the conclusion that the LKS would not be useful for missile defense; Chelomei was reprimanded for working on an unauthorized project. Previous setbacks on his projects never had much effect on the headstrong designer, but the LKS came to a definitive end when Chelomei died in August 1984. The mock-up was apparently destroyed in 1991.

What was necessary for it to succeed: OKB-52 were right that Buran would take too long and cost too much. Originally planned to fly in 1983, the Soviet shuttle made its sole, automated flight in November 1988; even then it was not completely fitted out and was only suitable for a 206-minute flight (and the next was not scheduled until 1993!) Something like 20 billion rubles, at a time when the ruble was officially marked at better than par to the US dollar, were spent on the program.

Even at the time there was resistance to the big orbiter, but NPO Energiya and Valentin Glushko‘s grip on the Soviet manned space program was firm. First you probably have to get it loosened somehow, though not so much that Chelomei and OKB-52 took over for them—as was discussed in the previous post to this blog, that would have left the USSR flying TKS spacecraft and not LKSes.

The difficult thing here is that if a small spaceplane got built there are two other, likelier candidates. Prior to about 1990 it probably would have been the other 20-tonne study mentioned at the beginning of this discussion, Mikoyan’s. The Spiral project got even further along than LKS did, to the point of a subsonic demonstrator and orbital re-entry tests of scale models. After 1990, NPO Molniya, builder of the Buran shuttle, floated the MAKS shuttle, which introduced the wrinkle of being air-launched by the An-225 superheavy cargo plane originally designed to cart Buran around.

As a result, unless one can cook up a Soviet leader circa 1983 who had the desire to save money of Mikhail Gorbachev while also having the willingness to rise to the challenge of the Strategic Defense Initiative, the LKS probably does not fly.


Light Space Plane, LKS“, Anatoly Zak.

‘LKS’, The Chelomei Alternative to Buran“, Giuseppe di Chiara.

Malysh v teni «Burana»: Sovetskiy legkiy kosmoplan“, Oleg Makarov. Popular Mechanics (Russian Edition) #93. July 2010.

“The Soviet BOR-4 Spaceplanes and Their Legacy”, Bart Hendricx, The Journal of the British Interplanetary Society, vol. 60. 2007.

Energia-Buran: The Soviet Space Shuttle, Bart Hendricx and Bert Vis.