TMK-1/MAVR: Red Planet

MAVR sketch schematic

Soviet-era schematic of MAVR, provenance and copyright status unknown. Please contact the author if you know of its source. 2 is the greenhouse, 3 is the drop probe for Mars, 9 the probe for Venus, 10 the telescope, and 11 the living quarters.

What it was: Two separate, competing Mars flyby/lander missions (with the same name) from OKB-1, synthesized into a Mars/Venus flyby mission that was the original purpose of the N1.

Details: Wernher von Braun was famously focused on Mars for much of his life, so it’s no surprise that there were two serious proposals to send American astronauts to our next neighbour out during his heyday at NASA. Less well-known is that Sergei Korolev was likewise enamoured of a Mars mission. When the N1 rocket was first floated in 1956, it was quite specifically intended as a launcher for Korolev’s early partner Mikhail Tikhonravov’s proposal of the MPK (марсианского пилотируемого комплекса, “Mars Piloted Complex”). The MPK spacecraft was wildly ambitious—a 1630 tonne ship requiring 20 to 25 N1 launches!—and never even got to the point of sketch plans.

The basic reason for the MPK’s enormous mass was that it was both a landing mission and relied on chemical propulsion. That implied two possible routes out of the dilemma, and in the wake of Korolev and OKB-1’s success with Sputnik, work got underway on studying both under the umbrella name of TMK (Тяжелый Межпланетный Корабль, “Heavy Interplanetary Spacecraft”). One group headed by Konstantin Feoktistov—later famous as a member of the first multi-person crew aboard Voskhod-1—studied an ion-propulsion driven landing mission, while Gleb Maksimov spearheaded a conventionally propelled flyby craft.

Feoktitsov’s TMK settled on a nuclear reactor to power a “slow but steady wins the race” approach that would spiral up, unmanned, through the Van Allen radiation belts. A conventionally launched mission would sprint through the belts and catch up, depositing cosmonauts aboard this spindly-looking ion drive-driven craft for the long journey to Mars. This arrangement initiated one “look” for Soviet and Russian long-term manned missions since then: the dangerous reactor, its engine, and the necessary cooling vanes were all arrayed along a long boom that kept them away from the fragile men aboard.

Maximov’s TMK was far more conservative from a modern perspective, and actually somewhat resembles both the MVF and Skylab. This was the option selected for moving forward. By the end of 1961 the basic parameters of the craft were settled and the mission tentatively aimed at leaving Earth on June 8, 1971 and returning on July 10, 1974—by far the longest manned mission seriously considered of which the author is aware, topping even the Triple Flyby variant of NASA’s MVF.

During coast and flyby it would have been 12 meters in length and weighed 35 tonnes—prior to Mars injection this would have been 75 tonnes including propellant, hence accounting for the lifting capability of a single N1. There would have been 50 cubic meters of space inside, split evenly between habitation and work space. A visual-light telescope for astronomical observations was attached to the side, a communications antenna to the fore, and a spread of solar panels girdled it. During coast the craft would have rotated end-over-end for a bit of artificial gravity, and during flyby there was an unmanned probe to drop off for landing. At the end of the mission a return capsule, nestled in the aft end to that point, would bring the cosmonauts back to the ground.

Both life support and food would have been dependent upon a greenhouse based on Chlorella chlorophyte algae, which was calculated to give better value for mass than chemical oxygen plants: 27 kilograms of oxygen per day per kilogram of algae. The food it made would have been supplemented partly by prepared stores. Getting this plant (no pun intended) up and running was considered the key breakthrough needed for the craft, and considerable work was done through the 1960s. Three men were sealed into a close-looped simulator ecosystem based on it in 1967.

A mockup of the MAVR (MArs-VeneRa) itself—as TMK-1 was renamed once a Mars/Venus flyby path was found that was shorter than the 1000-day mission mentioned above—was begun in 1964 but foundered due to zero funding.

What happened to make it fail: MAVR was ready to roll at exactly the wrong time. Khrushchev had grown disenchanted with Korolev’s follow-up to the R-7 missile, the R-9, and instead was coming to favour the line of storable-propellant missiles developed by Mikhail Yangel. Vladimir Chelomei jumped on this and proposed his own set of manned spacecraft, one of which was for interplanetary voyages, after poaching engine designer Valentin Glushko from Korolev to build his own rockets.

By the time Korolev regained control of the Soviet manned space program he and his nation’s leaders had decided that the gauntlet thrown down by Kennedy for a race to the Moon was serious, and moreover that they should pick it up. The N1 was “stretched” to become a Moon rocket, the Mars mission was put off into the indefinite future, and the rest is history.

What was necessary for it to succeed: Getting people to Mars has turned out to be far harder than expected, so the breezy optimism that had the MAVR at Mars by the mid-1970s is hard to sustain. A lot of things went against it: the early-60s infighting in the Soviet space program, uninterest in space on the part of the Soviet military, Korolev’s egotistic insistence on going head-to-head with Apollo, the shift in the USSR’s manned spaceflight focus to shuttle and space station during the 70s…the list goes on.

One thing that would have cleaned up a lot of them, or at least softened their impact, was the transfer of the space program away from the Soviet military, in particular the GRAU which funded the rockets. They wanted missiles not launch vehicles, and so logically if Khrushchev has been serious about wanting a space program he would have accepted a proposal from Korolev made post-Sputnik that OKB-1 be reorganized as a civilian organization like NASA. It didn’t happen.

One more note: long-time readers with good memories might have noted that the initial dates selected for the mission (though it was extraordinarily unlikely that the Soviets could have hit their targets) were roughly similar to those mentioned in our discussion of the NASA Mars-Venus Flyby. As mentioned in that post, there was a tremendous solar flare in 1972 that, by NASA’s estimate, would have hit anyone outside of the Earth’s protective magnetosphere with roughly 4 grays of radiation, with death resulting in the next few weeks.

A fine image of what MAVR might have looked like as it passed Mars can be seen on the Deviantart page of Polish artist Maciej Rebisz.


Mars Expedition 1969: NASA’s Waterloo (Integrated Program Plan, Part I)

A cutaway view of the Mars craft proposed by MSFC in 1969.

A cutaway view of the Planetary Mission Module (centre) and Mars Expedition Module (right) on top of the Nuclear Shuttle (fully visible on the second ship in the background). Public domain image from the Marshall Space Flight Center, NASA. Click for a larger view.

What it was: NASA’s follow-up to the Apollo program. A manned mission to Mars would have been launched in November 1981, brought twelve men to Mars—six of them landing—and then returned to Earth in August of 1983 (with a flyby of Venus along the return route). There would be two more manned missions by the end of 1985, and a manned base by the middle of 1987.

Details: Neil Armstrong stepped onto the Moon on July 21, 1969 and the obvious next question was “Now what?”

NASA had been answering it intermittently for years prior to this but now they got down to business. In particular, while they supported the Apollo Applications Project they were not content to stick to those missions’ main goal: to find out new things to do with the hardware they had already developed. Quite reasonably they decided that they needed to carry onwards and upwards with their engineering. Not only was a manned mission to Mars the obvious next step from an exploratory standpoint, it had the advantage of requiring that they move beyond Apollo equipment.

To that end they turned once again to Wernher von Braun. This was the culmination of his life dream: he’d published a Mars program in 1948, made a splash with the variant of it published in Collier’s in 1954, come up with another smaller expedition in 1956, and then sponsored the so-called EMPIRE and UMPIRE studies in 1962-64. On August 4, 1969 he made a presentation of what would be his final Mars proposal to the Space Task Group (STG), chaired by Vice President Spiro Agnew.

The mission was to be the penultimate part of a two-decade effort, the Integrated Program Plan, which could really be thought of as “Apollo 2.0”: another vast effort with an end goal, designed to replace the one that had just finished. As such it was part of an integrated whole that developed orbital operations into a finely tuned science, first by practicing with the Apollo Applications Program space stations and lunar base. One of the tools was to be a new space-only booster based on NERVA—which is to say, the first ever nuclear thermal rocket. This piece of equipment, dubbed the Nuclear Shuttle, was intermediate in mass between the second and third stages of a Saturn V, and had a higher specific impulse than any rocket ever flown.

Individual Nuclear Shuttles would be fueled in orbit with liquid hydrogen and used to push men and cargo to the Moon, then the empties returned to Earth orbit when they could be refueled and used again—up to ten times in all. Regular Saturn V launches would occur all through the early to mid-70s, building a space station and generally preparing the necessary infrastructure to be a “gas station”.

Meanwhile the other necessary equipment would be tested as part of an Apollo Moon base (basically a revival of the ALSS Lunar Base, which had been cancelled when new Saturn V production went into hiatus). There would be tests of the Nuclear Shuttle by the end of 1977, and 25 men living on the Moon by 1982.

With all that shaken out, the Mars mission would begin on November 12, 1981 with two ships launched on a Mars-bound a trajectory from low-Earth orbit. Each would consist of three Nuclear Shuttles strapped in tandem and a Mars craft made up of a Planetary Mission Module (PMM) habitation section and a Mars Excursion Module (MEM) lander mated to the tip of the one in the centre. The two side Shuttles would get the centre one and its payload up to speed, then peel loose and re-enter Earth orbit for reuse, while the two diminished mission craft would carry on their way.

There were two because the mission had the unique profile of backing itself up. Strictly speaking only one would be necessary for the mission, but the second would fly in formation to be a lifeboat in the case something went horribly wrong on the first—and the first served the same purpose for the second.

This kind of redundancy was necessary because the mission’s twelve crew were going to be away a long time. They’d arrive at Mars on August 9, 1982, stay there for almost three months, and then return to Earth for August 14, 1983: 640 days in all. In theory you wanted to minimize the weight of what you sent, but no margin for error meant nothing could go wrong without endangering the whole mission. NASA had always operated on the principle that you needed something to work with in case of an emergency, a principle that would prove its worth a few months after von Braun’s presentation when one whole side blew off of Apollo 13’s CSM and the astronauts on board were able to ride the excess margins back to Earth. Away from Earth for far longer than any space mission flown to that point, the Mars expedition would get its margin by literally flying two missions at once.

While at Mars six astronauts would stay aboard the PMM and Nuclear Shuttle combinations, flying in an elliptical orbit (a clever innovation by von Braun which made docking harder but cut the mass needed for the mission in half). After a remote sampler determined that it was safe to descend, six more astronauts would go to the surface in two groups of three aboard the Mars Expedition Modules, a capsule derived from the cone-shaped Apollo Command Module. They would slow down in what had only recently been discovered to be Mars’ very thin atmosphere by combination of a parachute, a ballute (a balloon-shaped inflatable parachute that works well at low atmospheric densities), and finally retrorockets starting three kilometers up.

Cutaway view of a MEM

Cutaway view of a MEM lander. Public Domain image from NASA’s Humans to Mars: Fifty Years of Mission Planning, 1950-2000. Click for a larger view.

A MEM could support its crew on the ground for up to sixty days, then its upper stage could climb back into orbit for rendezvous with the PMMs and Nuclear Shuttles. The latter would then fire up one more time and start the long journey back to Earth on 28 October, 1982.

The mission was not quite done, however. Their trajectory would take them back inside Earth’s orbit on a flyby of Venus on February 12, 1983. While this was a second opportunity for scientific study, it was primarily a speed-shedding maneuver. Four probes would be dropped on the way by.

Having got the right trajectory and speed, the two Mars craft would pull into Earth orbit where they would dock with the space station (while not the Orbiting Quarantine Facility, which was proposed several years later, it would serve the same purpose). From there they would be picked up by the Space Shuttle for the last leg of the journey home. If for whatever reason the space station didn’t exist or wouldn’t be suitable for this, the mission could be designed instead with an Apollo-style command module would let the crew splashdown directly to Earth.

Note that four of the Nuclear Shuttles had returned to LEO near the start of the mission; now the last two had done the same and so had their associated Mars craft. Only the MEMs would have been used up. Accordingly the ships would be refurbished and sent out again in 1986. Meanwhile, a second pair of ships would have been launched early in 1983, and on return be re-launched in 1988. By mid-1989, the intention was to have a 48-man semi-permanent base on Mars.

Bearing in mind that the proposal was part of a larger manned space effort including the Space Shuttle and a Moon base, the total cost of NASA’s programs was estimated about US$7 billion per year through at 1976 and $8 to 10 billion for the few years after that. The Space Task Group accepted von Braun’s Mars proposal and the NASA Integrated Program Plan as a whole, and passed it on to President Nixon on September 15, 1969.

What happened to make it fail: There was an utter disconnect between what NASA thought they should get in funding and what everyone else in the government was willing to give them. Even the Space Task Group was uneasy about the von Braun plan and offered two decompressed (and cheaper) versions of it—one where the Mars landing didn’t take place until 1986 and another where the landing was the goal but there was no set date for it. They still underestimated the opposition they would face.

Mariner 7 flew by Mars the day after von Braun made his presentation to the Space Task Group, and appeared to back up what Mariners 4 and 6 had shown previously: that Mars was a dead world, cratered not overly different from the Moon. We now know that by bad luck these missions happened to photograph the most inhospitable parts of Mars rather than the (slightly) more Earth-like northern Hemisphere, but that realization was in the future. Initial jubilation over Apollo 11 faded within a few months in favour of hard questions about why men had to go to Mars in light of what had been learned.

There was also a strong sense among the public and politicians that the United States had to get its house in order down on Earth. Protests against the Vietnam War were at their height and the country was still reeling from the urban riots of 1968. The Republicans had been voted back into power in the presidency in response (though the Democrats still controlled Congress) and Nixon was to continue the squeeze on the NASA budget that his Democratic predecessor had begun. When his director of the Office of Management and Budget Robert Mayo—an observer on the STG—objected to NASA’s proposal for FY 1971 coming in 29% over the cap he had imposed on them (US$4.5 billion instead of $3.5 billion) he convinced Nixon to put his foot down and NASA’s entire manned space program entered a death spiral.

By the time the dust settled almost all of von Braun and NASA’s programs had been cut. On March 3, 1970 Nixon announced that he’d allow only a truncated Apollo program, one space station (Skylab) and a commitment to the Space Shuttle. NASA would try one more Mars proposal in 1971; Wernher von Braun left NASA in 1972 and died in 1977 even before his proposed mission would have launched.

What was necessary for it to succeed: Almost everything was pointing against a Mars mission being approved in 1969. Public opinion was dubious (a Gallup poll in July 1969 found 53% of Americans against it—as Apollo 11 was going on!), the political interest to explore space was fading away in the Democratic Party as John F. Kennedy receded into the past, and Nixon was struggling with paying for the Vietnam War just as the US economy was sliding into recession. After his presidency various inside sources reported that he had been looking for a way to wrap up Apollo without looking like “The Man Who Killed the Space Program”; ironically, the less-ambitious options included in the STG’s report gave him the loophole he needed to dive through.

One possibility that could have brought about the mission would be a virtual tie in the space race, with the Americans and Russians getting to the Moon in a dead heat or possibly even the Russians getting a man on the Moon first. Under those circumstances the US might have committed to “Space Race, Round 2” and go for Mars. But this is a hard one to get flying, for all that it’s about the closest we’ve ever been to seeing a manned Mars mission. Even if it had been approved how much it would have had to shrink and delay as it rode out the 1973 Oil Crisis and the jittery economic conditions that lasted into the early 1980s is an open question.

Some very nice renders of this mission can be found on the DeviantArt page of Drell-7, AKA Tom Peters.

Manned Venus Flyby: Apollo’s Hail Mary Pass (Apollo Applications Program, Part I)

MVF Cutaway

A cutaway view of the Manned Venus Flyby spacecraft. Based on Apollo hardware, this remarkable proposal would have sent three astronauts on a year-long mission to Venus and back. Public domain image from the 1967 NASA document Manned Venus Flyby, via Wikimedia Commons. Click for a larger version.

What it was: A proposed post-Moon landing manned mission using Apollo hardware. It would have launched during a good alignment of Earth and Venus in November 1973 and taken three astronauts on a flyby of the planet Venus, returning to the Earth 13 months after launch.

A later variation of the mission ambitiously suggested using a better conjunction in 1977 to visit Venus and Mars on an outbound leg and Venus again on the Earth-return leg, however most of the work done considered the shorter Venus flyby.

Details: By the mid-1960s NASA was well aware that if they successfully completed the Apollo moon landings they would probably face a severe decline in budget for the manned space program. In the hopes of proving their ongoing worth they developed a few different post-Apollo proposals using evolutionary versions of the Apollo hardware, including plans for a manned lunar base, space stations, and planetary exploration. The latter two of these goals were at first grouped under the name Apollo X, and then became the Apollo Applications Program (AAP).

By far the most ambitious of the AAP missions was a manned flyby of the planet Venus. After two preliminary missions in Earth orbit to test the technology, a Saturn V launch would lift an Apollo Command Module into orbit. As in a typical mission, the first two stages of the rocket would be jettisoned. However the uppermost stage, the Saturn IVB, would be kept and drained of any remaining propellant. Using gear stored where the Lunar Landing Module would have been placed in a Moon mission, the astronauts would then rig it as a habitation module.

The resulting 33-meter-long spacecraft would leave Earth orbit on October 31, 1973 and travel towards Venus for 123 days. There would be a flyby on March 3, 1974. The craft would have been aimed to pass Venus as close as 6200 kilometers above the surface (one planet radius) very quickly—orbital mechanics would have it moving relative to Venus at a clip of 16,500 kilometers per hour—crossing the lit side of the planet. A sidescan radar would map the portion of the planet they could see as they flew by, and the astronauts would perform spectroscopic and photographic studies.

A series of probes was to be dropped by the spacecraft, and they were specifically enumerated in the proposal for the Triple Flyby variant of this mission that was mentioned earlier. Near closest approach the MVF would launch an orbiter and fourteen planetary probes; the probes would communicate with the orbiter, which would then beam the results back to Earth. Altogether the probes were:

  • Six atmospheric probes, which would enter the atmosphere at six locations: the planet’s solar and anti-solar points, its terminator and equator, and the middle of the light and dark sides. They would drop in ballistically and try to determine how Venus’ atmosphere increased in density the closer one got to the surface.
  • Four meteorological balloon probes. They would float in the atmosphere and try to learn how the Venusian atmosphere circulated as well as study smaller-scale winds.
  • Two “crash-landing” probes that would try to photograph the surface on the way down, much like Rangers 7, 8, and 9 did with the Moon.
  • Two soft-landers that would take surface photographs, examine the soil, and measure Venusian weather.

As well as acting as a communications hub, the orbiter would use X-band radar to map the planet.

MVF Mission Trajectory

The MVF’s trajectory. Detail from Manned Venus Flyby. Click for a larger view.

After that burst of activity the MVF craft would then return home, taking 273 days more to loop out to 1.24 AU from the Sun on a hyperbolic trajectory and eventually swing back to Earth. The astronauts’ landing on Earth would happen on December 1, 1974—total mission time would be 396 days. The Triple Flyby variant would have taken more than 800 days starting in 1977.

When not at Venus, the MVF astronauts would have studied the Sun and solar wind as well as making observations of Mercury, which would be only 0.3 AU away two weeks after the Venus flyby. To keep them occupied otherwise their habitation capsule would have been outfitted with a small movie screen (to show 2 kilograms of movies allowed), and a “viscous damper exercycle/g-conditioner”. The crew would also be allowed 1.5 kilograms of recorded music, 1 kilogram of games, and 9 kilograms of reading material. Hopefully they would choose wisely.

What happened to make it fail: The MVF was part of the Apollo Applications Program, and the AAP was killed dead on August 16, 1968 when the House of Representatives voted to cut its funding from US$455 million to US$122 million. President Johnson accepted this as part of a larger budget deal that kept NASA’s near-term goals safe, though even at that the agency’s entire budget dropped by 18% between 1968 and 1969. The only AAP mission to survive was Skylab.

What was necessary for it to succeed: It’s tough to get this one to work as it’s difficult to see any advantage to sending people on this mission. Mariner 5 had already flown by Venus in 1967 and NASA was able to send a robotic orbiter as part of the Pioneer 12 mission in 1978, just a few years after MVF would have flown.

Even the many probes that the MVF would leave behind at Venus had no obvious connection to the manned part of the mission; it would have been easier to send an unmanned bus of similar size and drop the probes that way. There would be no need then for heavy food, water, or air, or the space for people to move around. And unlike the manned mission there would be no need to bring the bus back, greatly reducing the mission’s difficulty. About all the manned mission had going for it was an opportunity to see what kind of effect a year in microgravity would have on humans, and that could just as easily be determined using a space station in low Earth orbit.

On that basis we also need to be aware that Congress asked hard questions about the purpose of NASA’s manned Mars mission plans in the late 1960s and were hostile to all of them. If Mars wasn’t going to get any money, it’s hard to see what could influence them to fund a mission to Venus.

Finally it needs to be pointed out that no matter even if the MVF launched, nature itself probably had this mission’s number. We didn’t have a very good understanding of the Sun at that time, having only observed one solar cycle from above the atmosphere when the flyby was proposed in 1967. While the launch window was deliberately chosen to be near a solar minimum, and the flyby craft was to have a radiation lifeboat in the equipment module, the mission would have run into an unforeseen natural event on the way back to Earth.

On July 5-6, 1974 the Earth was hit by a big coronal mass ejection (CME), a storm of electrons and protons thrown off of the Sun. People down on Earth were protected by the planet’s magnetic field, as usual, but the astronauts coming back from Venus wouldn’t have been so lucky. Their line to the Sun was several degrees off from the Earth’s (at the time they would have actually looped out past Earth as their trajectory slowly took them back home), but CMEs can cover quite a bit of space. Had the mission actually flown, the astronauts on-board may well have died of radiation sickness after being hit with more (and more energetic) solar protons than their spacecraft was built to handle.

The saving grace here is that coronal mass ejections were discovered in 1971, so the initial plan probably would have been called off rather than risk casualties, or at least be reconfigured to give the astronauts the protection the 1967 plan failed to give them.

An interesting simulation (using the program Orbiter) of how the MVF mission would have run can be seen on YouTube.