Man Very High/Project Adam: Mercury Before Mercury

Adam

The Mercury-like mission profile of Project Adam. Originally based on the cramped Project Manhigh capsule, by the time of this proposal the astronaut’s pressurized area was even smaller. Public domain image. Click for larger view.

What it was: The Army Ballistic Missile Agency’s attempt to capitalize on their successful riposte to Sputnik, Explorer 1, after the embarrassment of Vanguard TV3. Having lost the laurel of “first satellite” in frustrating fashion, Wernher von Braun‘s group quickly suggested a manned suborbital program, building on the US Air Force’s Project Manhigh, to try and take the prize for “first man in space” as quickly as possible.

Description: By the mid-1950s the USAF had got down to business of studying the effect of extremely high altitudes on pilots. One of the programs they ran was Project Manhigh, which lifted a pilot to 30 kilometers high twice in the months immediately preceding the launch of Sputnik 1.

Manhigh crammed a human being into a pressurized aluminum gondola weighing just 598 pounds (not including ballast), or 271 kilograms. The pill-shaped craft was 8 feet tall and 3 feet wide, or 244 cm × 91 cm, and that’s the first time I’ve had to use that unit in describing a crew compartment. Unsurprisingly, it housed one, though on the second flight it housed him for a remarkable 32 hours.

However, in the scramble that followed the unexpected dawn of the Space Age, the Manhigh gondola was a resource, and it was one that the ABMA latched on to, firing off a proposal in January of 1958, a few weeks before their modified Jupiter-C put the USA’s first satellite into orbit.

Simons

Major David Simons in one of the original Manhigh gondolas. Apart from a thin aluminum shell, that was it in its entirety. Image from LIFE magazine, September 2, 1957. Click for a larger view.

Not even the 1950s military was quite prepared to fire a naked Manhigh gondola to space—they were usually lifted and returned gently by balloon, with only a shock absorber needed for the landing. So the question was what needed to be done to bridge the gap between its original capabilities and a minimal craft that could withstand a swift trip above the atmosphere. Von Braun’s proposal gave one possible answer.

First named Man Very High, the initial proposal was for the Army to supply a modified Redstone based on the Jupiter-C used to launch Explorer 1 and an exterior shell using the principles of the Jupiter’s nose cone to handle the heat of flight and re-entry. The Air Force would supply a passenger cabin derived from the Manhigh capsule, and the Navy would handle recovery procedures. As part of this von Braun invited Manhigh fliers Joseph Kittinger and David Simons to Huntsville to see about adapting a Manhigh gondola for even greater altitude.

The Air Force as a whole was uninterested, though, so by March 1958 the ABMA rebranded Man Very High to Project Adam (a biblical reference, not a Frankenstein riff), and made it a joint Army/Navy project. Now the Army handled everything to do with the rocket and spacecraft, with the Navy continuing to be relegated to recovery and the USAF doing nothing at all. This they then submitted to ARPA the next month, this being the newly formed agency devoted to the military and civilian use of new technology and the unspoken mandate “Don’t let the Russians surprise us again”.

This ultimate version of Adam used two nose-cone derivatives arranged base-to-base. The upper cone would occupy the usual position of a Redstone missile’s tip, while the lower cone would be embedded tip-down in the body of the missile. This lower cone would house the astronaut and the various life-support and guidance equipment he would need. In particular, a Manhigh-like capsule would be rigidly installed horizontally, at the cone’s widest point, and the pilot would be loaded in from the gantry tower on a sliding wheeled sled before the cap sealed him in. This horizontal arrangement strongly implies that the capsule would have been even smaller than the Manhigh gondola, as the Jupiter-C was not quite 70 inches in diameter (177 cm), and no sketch of the Adam perched on top of its launcher shows a bulge near the top of the rocket. On the other hand, another diagram showing only the lower cone has its base clearly larger than this, and a third schematic of the crewed interior shows the pilot at a slight angle, feet downward. Make of that what you will.

egress

Getting onboard the Project Adam capsule. Public domain image.

In any case, with the pilot bolted into place more than seated, the Jupiter-C would be lit and our astronaut would be underway on his journey. After reaching the end of the rocket’s burn time, the double-cone craft would be cut loose, sail past apogee at 150 miles (240 km), the cut loose the upper cone as superfluous. The lower cone containing its crewman would re-enter, with deployable vanes supplying some steering, to water-land under a parachute.

Much like the first two Mercury flights he wouldn’t be going too far or for too long: six minutes of burn time, ten of free-fall, and a symmetrical 150 miles downrange to a splashdown to the north of the Caribbean Sea. Total price tag was claimed to be US$4.75 million (down from about US$12 million for the earlier, USAF-using version), with the flight to take place before the end of 1959.

What happened to make it fail: When first proposed, it was subjected to some rough handling by NASA’s predecessor, NACA, which was then working on the X-15 program with the Air Force, and the USAF itself, which was working on their Man Into Space Soonest project. Ironically enough, considering how Project Mercury flew its first couple of times, NACA head Hugh Dryden pooh-poohed it by comparing it to a circus’s Human Cannonball act.

redstone

What the US Army claimed they were working toward with Project Adam, the Redstone Transport Vehicle. Public Domain Image. Click for a larger view

Dryden did have a point. Though the Army dressed up Adam as leading to troop drops from space, the hybrid Adam capsule-craft had no development potential. Conversely, once NASA absorbed Man In Space Soonest and Max Faget sketched out the Mercury capsule, they were on their way to something that could go into orbit on top of the Air Force’s pending Atlas and Titan boosters. That would lead the way to Apollo in the long run (Gemini not being even a twinkle in anyone’s eye at that point). Meanwhile, while the Army had boosters in development to match the two Air Force rockets they were much further behind.

With all of NACA’s relevant people now heading NASA, and with NASA given a strong mandate to run the space program, von Braun’s group and the Army were frozen out until such time as the Redstone Arsenal was handed off to the new agency too, to become Marshall Space Flight Center. By then it was July of 1960, and Adam was long sidelined in favor of Mercury.

What was necessary for it to succeed: In the event, the key part of Adam—using a Redstone missile derivative to lob a capsule of some sort on a suborbital trajectory—was quickly absorbed into Mercury, and Americans #1 and #2 into space flew Adam-like missions downrange from Cape Canaveral to the Atlantic northeast of the Bahamas. So that part of the mission presents no real problems.

As for the capsule…Adam was proposed in a short section of time where everything about the United States in space was in flux. It’s largely forgotten now that NASA was actually the second agency set up in response to the USSR’s public relations coup, and that from February to the end of July in 1958 the responsible party was ARPA (modern-day DARPA). ARPA’s leaders were definitely interested in becoming something like NASA when it came to space: when NASA was formed, ARPA’s director, Roy Johnson, resigned in protest.

Fitting the project through this window of February to July ’58 would mean the USAF-less Project Adam would have had to be the proposal out of the gate, rather than ABMA trying to get the Air Force to develop the capsule as they did early on. As it was, the opposition from the Air Force and NACA meant that the ultimate Project Adam came too late to have a chance to move forward.

It’s actually a bit surprising that von Braun didn’t get his chance here—it’s hard to overestimate the prestige he had in the United States immediately following Explorer 1. Certainly his instinct that the Space Age was as much about the USSR and US showing each other up as it was about research was correct, despite the pushback on this from Dryden and crew.

As it was, Project Mercury won out and, notoriously just missing out on the first that Project Adam looked to accomplish: the USSR launched Yuri Gagarin on the first flight into space on April 12, 1961. The United States followed with Alan Shepard just five weeks later.

Sources
Von Braun: Dreamer of Space, Engineer of War, Michael Neufeld.

“First Up?”, Tony Reichardt. Air & Space Magazine, Sep. 2000.

How the U.S. Almost Beat the Soviets to the First Man in Space“, Ron Miller. Gizmodo, April 17, 2014.

Advertisements

Sidebar: The Tupolev OOS

clean

A model of the OOS shuttle, believed to be from a Russian magazine in the 1990s. If you have more information about this picture, please contact the author.

During the 80s the USSR’s space program stayed remarkably focused on Energia/Buran and the Mir space station, especially when compared to the infighting that marred the years 1966-1975. It fended off or adapted to a number of distractions, whether it was Vladimir Chelomei‘s repeated attempts to regain his previous, short-lived position on top of it, or airplane design bureaus suggesting anything from conservative alternatives to the recently discussed Myasishchev M-19 nuclear scram/ramjet.

The OOS was a late Soviet-era shuttle proposal from the Tupolev bureau, an also-ran in that country’s space business despite a strong position in civil aviation and strategic bomber development. Proposed as a fully reusable replacement for Buran sometime around the year 2000, it was about the same size as that craft or the American Space Shuttle, though somewhat heavier at 100 tonnes when fuelled. With a crew of two cosmonauts. it had a payload of 10 tonnes to and from low-Earth orbit.

If you’re a long-time reader of this blog, or just sufficiently into spacecraft, you probably slotted the shuttle pictured above toward the conservative end of that spectrum. Apart from the more-rounded contours, it looks to be much like the Shuttle, particularly in the shape of the underside. There, too, we have the usual ceramic tiles for dissipating the heat of re-entry. The engines are not visible, but I can tell you that there were three, burning LH2 and LOX during the ascent to orbit (though, curiously, switching out the hydrogen with kerosene for orbital maneuvers). Knowing that would likely not change your opinion at all.

Given that it’s was to be fully reusable, the ten-tonne payload mentioned earlier may have got you wondering, though. The actual American and Soviet shuttles had payloads in the 25-30 tonne range, so alright—there’s clearly some sort of tradeoff there. You’d be well-advised to wonder about the rest of the OOS’s configuration. Side boosters but no external tank? Perched on a reusable rocket in some manner, maybe?

Well, no. “OOS” stood for Odnostupenchati Orbitalni Samolyot, ‘one-stage orbital plane’, But a single-stage-to-orbit craft the size of the Orbiter? Surely that’s not possible.

This goes to show that you don’t think like a Soviet aircraft designer circa 1989. The OOS was to have been air-launched, and the other half of the system was the Antonov AKS:

AKS

Aerospace aficionados will remember that the An-225, which was used to piggy-back the Buran shuttle around the Soviet Union, was by most measures the largest aircraft ever built. This is two of them, one wing apiece removed and replaced with a sort of aerodynamic bridge, and then 675 tonnes of spacecraft and rocket propellants attached to its underside. It had twelve turbojet engines for when it flew without the orbiter attached (the dark circles in the diagram above, at lower right), with a supplementary ten more being added during launch operations (the white circles). The Aristocrats! With a length of 83 meters (272 feet), a wheelbase of 40m (131 feet) and a wingspan of 153m (502 feet), the combination came in at a whopping 1650 tonnes. By contrast, a fully fueled late-model 747 has a maximum takeoff weight of just under 440 tonnes.

There has been only one successful air-launching system in the world to date, Orbital ATK’s Pegasus. It weighs 23.1 tonnes and can put 0.44 tonnes in orbit; it’s launched from a Lockheed L-1011, already getting into the neighborhood of large airplanes. So start with some skepticism that 20 times this in launch mass and payload are a possibility for the late-era USSR.

Further, I haven’t (unfortunately) been able to find a detailed description of the AKS/OOS’s mission profile. I’d like to see it because I’m having a hard time picturing what the moment of separation would look like. Or rather, I have an image of the support crew aboard the AKS bouncing around like ping-pong balls in a boxcar once the plane, straining to get the orbiter to altitude, suddenly cuts loose 675 tonnes. For that matter, the OOS would have to light its engines pretty quickly thereafter or defeat the purpose of an air launch. As these were in the same class as the RS-25’s on the American Shuttle—the noise aboard the AKS, now presumably not all that far above and behind it, would have been intense.

I’m on record for my begrudging appreciation of the come-what-may technological megalomania that gripped the superpowers post-WWII. The US grew out that uncritical mindset after Love Canal and Three Mile Island, while the Soviets carried on until 1989. That extra time coupled with fossilized technocrats in charge allowed awe-inspiring audacity in technology of it to grow even greater than it did in the West.

Even so, I can’t imagine anyone with the power to make the Tu-OOS happen actually doing so. It would have been an immensely expensive and difficult project right at a time when the Soviet Union was in no position to take one up, and technological limitations would have prevented anything like it at an earlier point in that country’s history. The OOS/AKS was a paper project, and would have remained so.

Sources:

OOS, la bestia de Tupolev y Antonov

OOS, el sistema espacial de lanzamiento aéreo definitivo

Artist Vadim Lukashevich has numerous renders of the AKS/OOS combination on Buran.ru (screll down to the second half of the page).

Readers will note a lack of primary sources here. I’m convinced of this project’s existence, but any pointers to a source that’s a little more direct than what I’ve relied upon here would be most welcome.

 

The Douglas ASTRO: An Air Force Launcher

douglas-astro

The ASTRO, as pictured in the September 3, 1962 issue of Missiles and Rockets. Image artist unknown and copyright status uncertain, but believed to be in the public domain. Via the Internet Archive.

What it was: A lifting body craft proposed to the USAF by Douglas Aircraft. It would initially be used as a suborbital trainer then, after up-scaling and being paired with a second lifting body in an unusual nose-to-tail arrangement, evolve into a fully reusable vehicle with a nine-tonne payload capacity to LEO.

Details: In late 1962, the USAF was on the cusp of deciding how it would go forward with its plans to put military men in space. The X-15 had made its first flight mid-year, and the X-20 program was ramping up. Doubts about the latter were getting stronger, though, and would ultimately result in the Air Force deciding to work on the Manned Orbiting Laboratory instead.

It was at this point that an article was published in the now-defunct Missiles and Rockets magazine outlining a proposal from Douglas Aircraft that was supposedly being evaluated by the USAF. What it outlined was a two-part development program that would check the usual laundry list of military applications for space as perceived in the early 1960s.

The core of the ASTRO (Advanced Spacecraft Truck/Trainer/Transport Reusable Orbiter) was the answer to a question the USAF had proposed to North American Aviation and Douglas, as well as Boeing, Vought, and Republic: how to train pilots for the X-20 on actual flights prior to the X-20 being built. North American had come back with what they called the STX-15, which was a way of reconfiguring an X-15 to have the projected flight characteristics of an X-20 (except for, of course, the highest speed and orbital parts). The Phase I of Douglas’ ASTRO was their significantly more ambitious counter to the NAA proposal.

astro-schematic

A schematic of the ASTRO’s A2 vehicle, which would be both independent for suborbital hops, or be boosted to the point that it could be lifted into orbit by a derivative of the same vehicle. Note the booster nose’s ghostly presence at the far right of the image. Same source as previous. Click for a larger view.

Unfettered by the previously existing X-15, Douglas wanted to build a completely new craft dubbed A2, which would be capable of suborbital hops of about 5000 miles (8000 kilometers) after taking off from a runway under the impetus of a J-2 engine, the same rocket engine used by the Saturn V’s second and third stages. Pilots would get their space training, the USAF would have themselves a reusable vehicle with intercontinental range which could carry ten people, or a similar amount of payload. Two RL-10s, as used on the Centaur, would provide a little extra oomph.

Phase II was where Douglas diverged from the question being asked. Take the A2, modify it so that it only carried one crew and two extra J-2 engines, then stick it nose to bumper on the end of another A2 built to the Phase I spec. Turn it 90 degrees and launch it vertically, with the two separating from each other at altitude and speed (both unspecified). The sole crew member aboard the booster would glide back to Earth, while the uppermost A2 would ignite its engines, hopefully after allowing a bit of distance to build from the booster, and carry on into orbit. Douglas projected two crew and about a tonne of cargo to LEO in this configuration.

Phase III scaled up the booster, now dubbed B, and equipped it with two J-2s and one M-1, a never-built LH2/LOX engine that dwarfed even the F-1 engines used on the Saturn V’s main stage. Also launched vertically, this would be the ultimate version of the craft.

The full, two-stage Phase III vehicle was to have been 159 feet long (48.5 meters) and while mass was not mentioned the propellant capacity of the stages (165,000 pounds for the A2 and 594,000 pounds for the B) are—this suggests a total loaded vehicle mass at launch of about 380 to 400 tonnes. Total payload, as mentioned previously, was about nine tonnes, including crew, and there’s a sign that Douglas was nervous about this: the article specifically mentions wanting to launch due east from the Equator, which is an odd thing to be suggesting in 1962, well after the US had committed to launching from the continental USA.

If built, the program was expected to run from 1964 to 1970, with the first flight of the Phase III craft at the end of that period.

What happened to make it fail: It’s difficult to fit the ASTRO into the chronology of the X-20. Phase I appears to have been an attempt to come up with a “Gemini” for the X-20’s “Apollo”, giving the USAF the capability of sending pilots on long suborbital jaunts to train them for the environment they’d encounter when aboard the fully orbital X-20. Phase III would then have been a follow-up to the X-20, increasing crew capacity and payload over that craft.

If this is the case, then, it explains why the ASTRO never went anywhere. The craft made its sole notable public appearance in September of 1962, and American Secretary of Defense Robert McNamara was definitely thinking about cancelling the X-20 no later than March 1963—and possibly earlier. When the X-20 was stopped, then ASTRO would go with it. This is particularly true if one assumes, as seems likely, that the USAF was never very warm about the idea at all, and that it primarily existed as a pitch from Douglas leaked through Missiles and Rockets magazine to drum up support. There’s essentially no reports or discussion of ASTRO post-dating the magazine’s unveil.

What was necessary for it to succeed: It’s not easy to see a way forward for this one. X-20 was dead in the water less than six months later (eventually being formally cancelled in December 1963), and the payload capacity of even the Phase III ASTRO was marginal for what would have been an expensive program. There’s also the issue of Douglas vastly exceeding the question posed by the USAF—it’s unclear that there was any interest on the part of the Air Force in anything other than Phase I. This in turn defeated the purpose of building a fully operational craft for pilot training.

Sources

“Air Force Studies Space Trainer”, Missile and Rockets. September 3, 1962.

ACTS: Europe and Russia Try Again

acts

A somewhat notional view of the ACTS as envisioned once its capsule shape was selected in 2008. By developing a command module with relatively steep walls, the ESA and Roscosmos hoped to solve the problem of cramped quarters aboard the Soyuz, and handle up to six crew. Adapted from an image by Jérémy Naegel, used under a Creative Commons ShareAlike 3.0 license. Click for a larger view.

What it was: A traditional capsule-based spacecraft to be developed jointly by the European Union and Russia, after those two failed to reach agreement on the Kliper lifting body (and further on Europe failing to the get the Hermes spaceplane off the ground).

Details: It’s been interesting the last twenty years or so to watch the gold standard for new crew return vehicles move away from small spaceplanes and lifting bodies back to capsules, as had been the preference through the 1960s. The watershed was sometime around 2006, when mockups of NASA’s Orion ceased to show a lifting body and changed to a capsule, and right about when the tandem of EU/Russia stopped looking at the Kliper and started talking about the Advanced Crew Transportation System (ACTS).

At the end of 2005, the Kliper foundered on the fact that Russia was to design and build it almost entirely. Despite that failure, the ESA was still fetching about for a crewed space project as they had also been rebuffed in approaches to the United States about sharing development of Orion’s capsule prior to Kliper. And so Russia came back into the picture within a few months.

As it happened, the EU had been working on the ATV, an unmanned supply spacecraft for the International Space Station, and it had already been noted that it bore a certain resemblance to a spacecraft service module. “Why not,” the thought ran, “have Russia develop a crew capsule to put on top of an adapted ATV?” Do so and you’d end up with something usable in Earth orbit for short missions, such as going to the ISS.

csts_eurosoyuz

The so-called “EuroSoyuz” first envisioned for the ACTS. This image is even more notional than the previous, based as it is on ideas being considered at the time and not any actual plans. The habitation module at the left, in particular, never progressed beyond an intent to make one eventually. Image by Jérémy Naegel, used under a Creative Commons Attribution 3.0 License.

Initially the craft was envisioned by RKK Energia as sort of “Soyuz, Mark 2”, which Energia called the Soyuz-2, with a Soyuz-shaped re-entry module, if not the one from an actual Soyuz. Rather it would be oversized, perhaps derived from work down on a mid-80s Soyuz replacement called the Zarya. This had stuttered along as late as 1995, when it was jointly proposed by Energia, Khrunichev and Rockwell as a lifeboat for the ISS. The ESA and Russia committed to a two-year study of the idea, with the ultimate intention of producing a spacecraft that could orbit the moon. This configuration was still in the lead as of August 2007.

The study’s mid-2008 deadline coincided with that year’s Farnborough Air Show, and the details that were announced then had moved on from the initial concept. Now the upper half of the ACTS was a conical capsule, built by the Russians and integrated by them onto the European service module. Many sources describe it as Apollo-like, but it was fairly different in being much more vertical, a mere twenty degrees from vertical on its side walls. This was a throwback to a proposed European capsule, Viking, which had popped up for a while immediately post Hermes before fading out after one subscale, suborbital test (the Atmospheric Reentry Demonstrator) in 1998.

Though the craft was not designed to the point of precise specs, we know that it would have probably have been under 18,000 kilograms, as one of the proposed ways of getting one to orbit was via Kourou Space Centre on top of a crew-rated Ariane-5, though figures bounced around from as low as 11 tonnes and as high as 20. The Russians also talked about launching the ACTS from Vostochny, probably for use on an Angara A5 (though that rocket is still under development even as late as December 2016); a Proton was also a possibility if the difficulties of launching cosmonauts on top of rocket fueled with nitrogen tetroxide and UDMH, and there was nebulous talk of a Zenit derivative (a rocket that had not been used.in Russia as the dissolution of the USSR left its manufacturer in Ukraine).

The capsule would have been five meters across the base and with its high vertical angle would have been roomy enough for six astro/cosmonauts (or four, if going to the Moon); one source reports 2.5 cubic meters of space, but this is no larger than a Soyuz and seems unlikely.

Ultimately the plan was to have a habitation module too, and the responsibility for this was assigned to Europe, but until the core ACTS spacecraft was much further along this was little more than a planned future commitment, with no details at hand. At the forward end, ACTS would at first have a Soyuz-style docking arrangement to take advantage of the matching ports on the ISS. Once it began its lunar missions, though, the plan was to have a common active/passive system with the Americans’ future craft so that joint missions would be easier.

On re-entry, the Russian-made capsule would have borrowed a trick from previously mentioned Zarya: a re-entry to land under a minimal parachute, with primary responsibility for landing being passed on to 12 solid rocket motors that would begin firing at about 300-800 meters up. Retractable landing legs were also mooted, as part of a general desire to make the capsule re-usable (with one Russian official hopefully suggesting ten flights in a lifetime). Rumor had it that this hair-raising retro-motor approach was made necessary by the Russians insisting on their historical requirement that their crews return to land in Russia, and with much of Central Asia now thoroughly Kazakh, the area they had to hit was much smaller than before—and parachutes normally cause one to drift quite a bit.

What happened to make it fail: Europe started showing signs of cold feet in the spring of 2008, just as the ACTS was making its splash at the Farnborough Air Show. The reasons are bureaucratically murky, but seem to have reflected the ascendance of a faction in the ESA that wanted to focus on “ATV Evolution”, a more ambitious approach where they’d upgrade the ATV so that it could return cargo, then upgrade the return module into a capsule, and then even turn it into the core module of a small space station. All this would be indigenous to Europe, with no Russian involvement.

ACTS might have survived this, but two competing financial tides worked against it. The Great Recession kicked off in late 2007, and for the next six years Europe had to deal with repeated sovereign debts crises that made money scarce. Not only was ATV Evolution shelved, even a shared spacecraft with the Russians was too expensive.

In the other direction we had a surging price for oil and gas (bar a severe but short drop near the start of the recession), reaching $140 per barrel in June 2008. Replete with petrodollars, Russia came to the conclusion that they didn’t need to put up with European waffling any more and could go ahead with their own, solo version of the ACTS. Political opinion at home favored this course anyway, and local laws on technology transfer made it difficult for Roscosmos and Energia RKK to come up with a legal framework for transferring technical information on Soyuz and other ACTS-related work out of Russia. This last issue is what is generally cited in official ESA documents as the main cause of ACTS’ failure.

Then in August 2008, Russia invaded Georgia in support of separatists there, followed by a gas pipeline dispute with Ukraine in January of 2009 that affected several EU countries. European confidence in Russia as a partner nosedived, and it became politically distasteful for the ESA to continue working with their Russian counterparts on such a high-profile project. Both sides quietly went on their way.

What was necessary for it to succeed: ACTS as such could have gone ahead in the face of most of the difficulties just listed. Certainly the financial crisis could have been ridden out for a few years, and the Russia oil boom didn’t last. What’s been the real killer has been the frosty relationship between Europe and Russia, kept chilled by further events like the latter’s clandestine invasion of eastern Ukraine. It’s difficult to see ACTS restarting any time after 2008, despite occasional French noises about re-establishing partnership with Russia.

Unlike most other projects discussed here, though, ACTS didn’t lead to no flying craft, or even to one. Rather it’s changed into two, and that’s not even counting the ATV Evolution which the ESA bravely claims is still on the table despite little sign of movement for about eight years. The Russian ACTS derivative was first called the PPTS, then it became the PTK. While that project has faced a long and slow road, it was formally dubbed Federation this year and, is still looking like it will fly in the 2020s.

On the European side, NASA announced in January 2013 that the previous design of the Orion service module was being replaced with an ATV-derived service module for at least the EM-1 unmanned test out past the Moon, currently scheduled for a year next September. Whether it will be used again after that mission is an open question, but so far it looks like it’s going to be used once. The initial idea that the ATV would work if someone else supplied a capsule for it was right, they’d just picked the wrong partner at first.

So the ACTS has survived after all, and did so by being cut in two. As mentioned, the Russian half has a name already, but seems fitting to name the as-yet-anonymous American/European half after King Solomon.

Sources

“Advanced Crew Transportation System”, Anatoly Zak. RussianSpaceWeb.com.

“Collapse of ESA-Roscosmos Crew Vehicle Partnership Holds Lessons”, Peter B. de Selding. SpaceNews.

“Potential European-Russian Cooperation on an Advanced Crew Transportation System”, Frank De Winne. Belgian Science Policy Office.

LANTR LTV/LEV: A New Way to the Moon

lantr-lev-side-by-side-comparison

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

“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.

profile

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.

Sources

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

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.

Sources

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 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-3” of Max Faget‘s design, or similar), you’d board a Nuclear Shuttle-driven

mem-schematic

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 the crew 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. Marshall’s 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 the 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 unmasks this as 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.

Sources

“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.