20 June 2017

Safeguarding the Earth from Martians: The Antaeus Report (1978-1981)

The Viking 2 landing site in Utopia Planitia, a northern plain where water frost is seen on winter mornings. The lander touched down on 3 September 1976. A three-meter arm with a scoop on the end dug into the martian surface near the lander, collecting dirt to feed into its three biology experiments. The arm was also used to push rocks and dig trenches that enabled scientists on Earth to study the top 20 centimeters or so of the martian surface. Had the arm been able to dig down deeper - perhaps as little as 30 centimeters deeper - it would have encountered water ice and the history of Mars exploration could have been very different. Image credit: NASA
In the summer of 1978, 16 university professors from around the United States gathered at NASA's Ames Research Center near San Francisco to spend 10 weeks designing an Earth-orbiting Mars sample quarantine facility. It was one of a series of similar Ames-hosted Summer Faculty Design Studies conducted since the 1960s.

At the time, NASA actively considered Mars Sample Return (MSR) as a post-Viking mission. Agency interest flagged as it became clear that no such mission would receive funding, so publication of the 1978 design study, titled Orbiting Quarantine Facility: The Antaeus Report, was delayed until 1981.

The Summer Fellows noted that the three biology experiments on the Viking landers had found neither organic carbon nor clear evidence of ongoing metabolic processes in the soil they tested on Mars. Furthermore, the Viking cameras had observed no obvious signs of life at the two rather dull Viking landing sites.

Nevertheless, the Summer Fellows argued, "the limitations of automated analysis" and the fact that "the landers sampled visually only a small fraction of one percent of the planet's surface" meant that there could be "no real certainty" about whether Mars was lifeless. This, they argued, meant that, "in the event that samples of Martian soil are returned to Earth for study, special precautions ought to be taken. . .the samples should be considered to be potentially hazardous to terrestrial organisms until it has been conclusively shown that they are not."

Their report listed three options for attempting to ensure that samples would not accidentally release martian organisms on Earth. The MSR spacecraft might sterilize the sample en route from Mars to Earth, perhaps by heating it. Alternately, the unsterilized sample might be quarantined in a "maximum containment" facility on Earth or in Earth orbit, outside our planet's biosphere.

The Summer Fellows noted that each of these three options would have advantages and disadvantages; sterilizing the sample, for example, might ensure that no martian organisms could reach Earth, but would likely also damage the sample, diminishing its scientific utility. The scientists explained that the Antaeus study emphasized the third option because it had not been studied in detail previously.

The Summer Fellows explained the significance of the name they had selected for their Orbiting Quarantine Facility (OQF) project. Antaeus was a giant in Greek mythology who forced passing travelers to wrestle with him and killed them when he won. The Earth was the source of Antaeus' power, so the hero Hercules was able to defeat the murderous giant by holding him above the ground. "Like Antaeus," they explained, a martian organism "might thrive on contact with the terrestrial biosphere. By keeping the pathogen contained and distant, the proposed [OQF] would safeguard the Earth from possible contamination."

Five 4.1-meter-diameter cylindrical modules based on European Space Agency Spacelab module hardware would form the Antaeus OQF. The Summer Fellows assumed that the modules and many of the other components needed to assemble and operate the OQF would become available during the 1980s as the Space Shuttle Program evolved into a Space Station Program.

OQF assembly in 296-kilometer-high circular Earth orbit would need two years. It would begin with the launch of drum-shaped Docking and Logistics Modules together in a Space Shuttle Orbiter's payload bay.

The 2.3-ton Docking Module, the OQF's core, would measure 4.3 meters long. It would include six 1.3-meter-diameter ports with docking units derived from the U.S. version of the 1975 Apollo-Soyuz "neuter" design. Outward-splayed guide "petals" and a system of shock absorbers and latches would enable identical docking units to link together.

The Antaeus Orbital Quarantine Facility. Image credit: NASA
In addition to the Logistics Module, Power, Habitation, and Laboratory Modules would link up with Docking Module ports. When completed, they would form what the Fellows called a "pinwheel" design. The remaining two Docking Module ports would enable Shuttle dockings, spacewalks outside the OQF with the Docking Module serving as an airlock, and attachment of additional modules if necessary.

The 4.3-meter-long Logistics Module would weigh 4.5 tons loaded with a one-month supply of air, water, food, and other supplies. After a crew took up residence on board the OQF, a Shuttle Orbiter would arrive each month with a fresh Logistics Module. Using twin robot arms mounted in the Orbiter payload bay, the Shuttle crew would remove the spent Logistics Module for return to Earth and berth the fresh one in its place.

The second OQF assembly flight would see the Shuttle crew link the 13.6-ton Power Module to the Docking Module's aft port. The Power Module would then deploy two steerable solar arrays capable of generating between 25 and 35 kilowatts of electricity. Spinning momentum wheels would provide OQF attitude control and small thrusters would fire periodically to counter atmospheric drag, which would otherwise over time cause the quarantine station to reenter. The Power Module would also provide OQF thermal control and communications.

The OQF's five-person crew would live in the 12.4-meter-long, 13.6-ton Habitation Module, which would arrive on the third assembly flight. The OQF's "command console," five crew sleep compartments, and workshop, sickbay, galley, exercise, and waste management/hygiene compartments would be arranged on either side of a central aisle. The Hab Module would provide life support for all the OQF's modules except the Laboratory Module.

The Lab Module, delivered during the fourth and final OQF assembly flight, would measure 6.9 meters long and, like the Hab and Power Modules, would weigh 13.6 tons. Not surprisingly, the Ames Faculty Fellows devoted an entire chapter of the Antaeus report to the Lab.

Spacelab pressurized modules included a central corridor running their entire length. Experiment equipment lined their walls. The Spacelab-based OQF Lab Module, on the other hand, would have a central experiment area running most of its length with corridors along its walls. Most of the experiment area would be located within glass-walled "high-hazard" "Class III" biological containment cabinets similar to those at the Centers for Disease Control in Atlanta, Georgia.

The Antaeus OQF Lab Module included an independent life support system to help prevent contamination of adjoining modules. Grills in the floor and ceiling lead to air filters. The Mars Sample Return sample canister would enter the central experiment area from above. Visible are at least three microscopes. Image credit: NASA
Analysis equipment within the cabinets would include a refrigerator, a freezer, a centrifuge, an autoclave, a gas chromatograph, a mass spectrometer, incubation and metabolic chambers, scanning electron and compound light microscopes, and challenge culture plates. The crew would operate the equipment from outside the cabinets using sleeve-like arms with mechanical grippers.

The Summer Fellows provided no obvious aids for crew positioning. In the illustration of the Lab module above, scientists are shown floating without handgrips or feet or body restraints. Given the delicate and sensitive nature of the work they were meant to perform, this would probably turn out to be a significant omission.

The Lab Module would include an independent life support system with "high efficiency particle accumulator" (HEPA) filters. Experimenters would enter and exit the Lab Module through a decontamination area, where they would don and doff respirator masks and protective clothing. If a mishap contaminated the Lab Module, the module could be detached from the OQF and boosted to a long-lived 8000-kilometer circular orbit using a Laboratory Abort Propulsion Kit delivered by a Shuttle Orbiter.

Following the two-year assembly period, a rehearsal crew would board the OQF to test its systems and try out the Mars sample analysis protocol using biological samples from Earth. The Summer Fellows set aside up to two years for these practice activities. At about the time the rehearsal crew boarded the OQF, a robotic MSR spacecraft would depart Earth on a one-year journey to Mars.

Two years later and four years after the start of OQF assembly, a small Mars Sample Return Vehicle (MSRV) containing one kilogram of martian surface material and atmosphere samples would fire rocket motors to enable Earth's gravity to capture it into a high orbit. The sample would ride within a sample canister, the exterior of which would have been sterilized during Mars-Earth transfer. Meanwhile, a Shuttle Orbiter would deliver to the OQF the first five-person sample-analysis crew. It would comprise a commander (a career astronaut with engineering training) and four scientists with clinical research experience (a medical doctor, a geobiologist, a biochemist, and a biologist).

A Shuttle-launched remote-controlled Space Tug would collect the sample canister from high-Earth orbit and deliver it to a special "docking cone" on top of the Lab Module. This is not shown in the illustration of the completed OQF; in its place, one finds a cylindrical "Sample Acquisition Port." The canister would then enter the experiment area through a small airlock.

The first sample analysis crew would cut open the canister using "a mechanism similar to a can opener." They would immediately place 900 grams of the sample into "pristine storage." Over the next 60 days, they would execute an analysis protocol that would expend 100 grams of the sample. Twelve grams each would be devoted to microbiological culturing and challenge cultures containing living cells from more than 100 Earth species; six grams each to metabolic tests and microscopic inspection for living cells and fossils; 10 grams to chemical analysis; and 54 grams to "second-order" follow-up tests.

If the 60-day analysis protocol yielded no signs of life in the test sample, a Shuttle Orbiter would carry the 900-gram pristine sample from the OQF to Earth's surface for distribution to laboratories around the world. Based on highly optimistic 1970s NASA estimates of Shuttle, Spacelab, and Station costs, the Summer Fellows placed the total cost of OQF assembly and operations for this "minimum scenario" at only $1.66 billion.

If, on the other hand, OQF scientists detected life in the Mars sample, then analysis on board the OQF could be extended for up to six and a half years. Throughout that period, Shuttle Orbiters would continue to deliver a steady stream of monthly Logistics Modules; they would also change out OQF crews at unspecified intervals. In all, about 80 Logistics Modules would reach the OQF by the time its mission ended. The cost of this "maximum scenario" might total $2.2 billion, the Ames Summer Faculty Fellows optimistically estimated.


Orbiting Quarantine Facility: The Antaeus Report, D. DeVincenzi and J. Bagby, editors, NASA, 1981

More Information

Clyde Tombaugh's Vision of Mars (1959)

Peeling Away the Layers of Mars (1966)

What Shuttle Should Have Been: NASA's October 1977 Space Shuttle Flight Manifest

Making Rocket Propellants from Martian Air (1978)

Astronaut Sally Ride's Mission to Mars (1987)


  1. In reading the description of Antaeus, I couldn't help but be reminded of Michael Crichton's early novel The Andromeda Strain--although it would today be called a technothriller, Crichton, a doctor, did attempt to picture the scientific, engineering, and even the political and philosophical dimensions of a facility designed to analyze extraterrestrial life (coincidentally, I'm sure, Crichton's book, like Antaeus, posited a five-person team).

    Since The Andromeda Strain came out only two months before Apollo 11, this sounds apocryphal to me, but I've even heard it claimed that the decision to quarantine the returning crew (despite there being no expectation of even microscopic life on the moon) was influenced by popular concern sparked by the novel. On the other hand, the Mobile Quarantine Facility was a converted Airstream trailer, which seems a little improvised compared to all the other specialized hardware developed for Apollo.

    Am I correct that the Mars 2020 rover may be tasked with gathering and tagging samples for future recovery and study? Some version of the Antaeus concept might again be relevant for that, although perhaps with advances in technology since 1978, the Earth-orbiting analysis facility could be operated remotely from the ground, which would be safer and cheaper.


    1. I can't say much about any connection between THE ANDROMEDA STRAIN and Apollo planetary protection measures. You are right in saying that the Apollo measures seem improvised. I think it was a case of very few people believing that the moon might support living things - yet what if they were wrong? NASA had to at least seem to be making an effort. NASA published a history of planetary protection a few years ago in its formal history series - that might be worth a look.

      I've heard different things about Mars 2020 sample collection. I heard at one point that the plan was to collect rocks, package them up, and then drop them behind the rover like a trail of bread-crumbs. Then a fetch rover would come along later and gather them up and deliver them to the waiting Mars Sample Return lander. A 2016 infographic I have mentions caching samples - from the looks of it, drill cores - but isn't clear on whether they'd remain on board the rover. There've been plans to collect samples before - Curiosity at one point was meant to cache samples. Unless I'm mistaken, a "bin" was added to the rover and then removed to save weight. I'm relying on memory here, so I might have that wrong.

      As you probably know, there's back-contamination (introducing bugs to Earth) and forward contamination (introducing bugs to the world you want to explore). Scientists tend to justify prevention of the latter in terms of keeping the environment pristine for study. That is, they don't want to detect life on Mars and then determine that they've found Earth bugs they brought with them.

      Some folks argue that Mars is already contaminated and has already contaminated Earth - that the two planets have been trading material blasted off their surfaces by big impacts for a long time. Hence, no need to safeguard either world from contamination. Folks eager to land people on Mars and settle the planet especially seem to want to believe that it is either lifeless or populated with near-relatives of microbial life on Earth. Seems to me, though, that near-relatives should be more dangerous than totally alien living things.

      Not being a scientist, I don't have a professional opinion, though I do hope that we'll be careful, especially when we start drilling deep down into martian aquifers. The environment a few hundred meters down on Mars could be identical to the environment a few hundred meters down on Earth, and we know life abounds in rocks beneath Earth's surface. Why should it not be the same for Mars?

      I'm wandering around the topic here. Let me wind this up by saying that the old piloted flyby schemes that included a Mars Sample Return lander might have had the right idea. Open the sample in a sealed lab on board after the Mars flyby, check it out for nasty organisms using mice and fish and selected plants. If any are found, study the sample during the long trip home and them dump it (and maybe the entire lab). If any bugs get loose inside the spacecraft, see what happens to the crew - if they die, make sure their spacecraft misses Earth when it swings back around.


  2. I think it's ironic that after a journey of millions of miles the Viking lander came up short by maybe a foot of revealing the subsurface ice. Just those few extra inches & perhaps that sample return mission would have happened. Another one of those "what if moments".

    1. Had Mariner IV, Mariner 6, or Mariner 7 reached Mars just a little earlier or latter, one or another might have imaged Olympus Mons, the giant outflow channels, or Valles Marineris. Instead, they all neatly missed those landmarks, revealing instead craters, craters, and more craters. That contributed to the demise of the Mars/Venus Voyager program. It wasn't at all certain that Congress would fund Mariner 1971, and Viking wasn't entirely out of the woods until Mariner 9 imaged all the good stuff in 1971-1972.

      Here's another mind-blower - Viking 2 should have shut off its landing rockets at a higher altitude than it did. Instead, they remained on long enough to stir up the surface more than the scientists would have liked. They wanted a pristine surface for biological sampling. Had the motors stayed on too long in a place where the ice was closer to the surface, they might have revealed it, much as did the landing rockets on Phoenix.


  3. When I was in middle school (c. 1987) I did a presentation on the Orbital Quarantine Facility for my science class. I even made a crude model from dowel rods and cardboard, scaled to a toy space shuttle orbiter. This was back when I wanted to be an astronaut, probably because it seemed the best way to get as far from my middle school as possible. (The OQF also makes a cameo appearance in Kerry Mark Joels' "Mars One Crew Manual", which came out around that time.)

    Couple of years ago I was thinking about kitbashing a better scale model of the OQF for old time's sake, so I reread the Antaeus report. It struck me that it's really about lab equipment and protocols, with very little about spacecraft engineering and architecture. It pretty much handwaves it by assuming that by the time the mission happened, there would be a lot of off-the-shelf systems available that could be Lego'ed together to support the lab.

    One result of this is that the architecture is pretty much independent of the mission. I think the report even mentions this: once the sample-analysis mission was complete, the whole station could be repurposed for something else (like zero-g manufacturing) simply by swapping the lab module for some other mission module.

    1. The Antaeus OQF resembled other space station designs of the 1970s, which tended to avoid trusses. You are correct when you say that the Summer Fellows focused on the lab and life detection/analysis bits of their proposed program. Which I think makes sense, given that plenty of space station studies had occurred, but almost no orbital quarantine studies (and very few sample-return quarantine studies of any kind). They weren't in it for the engineering, so much.

      To me the Antaeus Report is a relic of a time when many people believed that the Space Shuttle would be so cheap that it would free up cash for things like Mars Sample Return. Instead, it pretty much ate everyone's lunch. A pity.


  4. Great article David! Viking, setting the standard for sterilization, had a number of followup mission proposals, including turning my Viking Lander (VL3) into a rover. It's am interesting part of the history.

    However my Lander was not completed as the budget was instead shifted to a complete Science end to end test complete with followup doc and instigating many additional changes. It was fortuitous, and VL3 was never needed as the flight spare it was intended to be. So all around good... for Viking to have the additional testing, and earth to maintain a unique artifact that I had the good fortune and geeky interest to save from scrap.

    Re: 2020, it IS still in the specs to cache samples for later retrieval, though the full definition of when and how is not determined, which is fine at this point because the caching is/can be the impetus needed to urge a sooner followup mission to retrieve for examination. The idea (I think) is to make them accessible for autonomous unit retrieval in lieu of waiting for manned... but don't quote me on that.

    Thank again for this retrospective!


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