The Problems of Simulating Mars on Earth

The psychological stress of spaceflight has always been a concern. One of the reasons there was so much banter during Apollo missions was because NASA was worried that if the astronauts stopped moving and had an opportunity to really think “I’m standing on the moon!” they would panic. But no one can generate banter for a mission lasting more than 500 days, especially when there is an increasing delay in communications. A crew going to Mars will need to have the mental stability – both as individuals and as a group – to maintain their own sanity and mentally survive going to Mars.  (Left, the Mars 500 Crew in May, 2011.)

This was the goal of the recent Mars 500 study, a joint project of the Russian Institute of Biomedical Problems in cooperation with the European Space Agency (ESA). Six men were isolated and confined to a mock spacecraft for five hundred and twenty days. The purpose was to  simulate a Martian mission and gauge the participants’ psychological reactions to the mission – simulations are another fascination of mine. Mars 500 “landed” back on Earth on November 4, so it’s still too early to know the long-term effects of the mission. But it’s not too early to question wether or not it was an effective measure of human factors on a long-duration planetary mission, or if there even is an effective way to test man’s psychological reaction to a trip to Mars. 

The simulated Martian mission “launched” on June 3, 2010.  Over the first seven months as the crew got further and further from Earth, the communications delay lengthened until voice contact became impossible and the crew was left with only written contact with mission control. On February 1, half the crew began transferring into a smaller landing module, and on February 8 the crew split into two halves. Three men descended towards the surface while the other three stayed in orbit. On February 14, 18, and 22, the landing crew made three egresses on a simulated Martian surface before lifting off from the analogue red planet on February 23. After a brief period of containment, the crew reunited on February 27 and began their long journey back to Earth. The communications delay shortened as they neared Earth, regaining voice contact with mission control a little less than a month and a half before “landing” on November 4. (Above, a schematic of the Mars 500 spacecraft.)

The crew consisted of six men – Italian Diego Urbina, Romain Charles from France, Russians Alexey Sitev, Sukhrob Kamolov, and Alexandr Smoleevskiy, and Wang Yue from China. Each was selected for their skills and work experience in the fields deemed necessary to send to Mars: medicine, engineering, biology, and computer sciences. (The Mars 500 facility. Not exactly the vacuum of space.)

Throughout the mission, the crew lived on a schedule similar to the astronauts in the International Space Station. They observed a seven day work week with two days off (unless an emergency arose), they carried out experiments, regular maintenance of their habitat, and completed a daily exercise regime to keep them physically fit. They lived off limited food rations and took infrequent showers to conserve their available water. Their quarters, however, were a little more comfortable. The four hermetically sealed habitat modules made the total “spacecraft” 19,500 cubic feet – about the same as five and a half regulation school buses.

The crew was under constant supervision and observation from mission control. Their vitals were constantly monitored, their psychological, medical, and physical well being was constantly recorded, as were their stress levels, hormone levels, sleep quality, and the effects of dietary supplements. The only part of the habitat that gave the crew somer respite from the Big Brother-esque watchful eye was the washroom. (Romain Charles undergoes a physical fitness test.)

Most importantly, mission control monitored the crew’s mood – how the work schedule, the supplements, and the confinement affected their ability to work and live as a team. But aside from the isolation,the simulation seems to have been relatively psychologically easy compared to what a crew will likely deal with on a real mission to Mars. (Romain Charles and Alexandr Smoleevskiy pose with the Mars 500 fitness equipment.)

As a simulation, there are obvious benefits to this kind of study. In a tightly controlled environment, it is possible to replicate the 24 hour 37 minute Martian day (called a Sol) with artificial night and day. Detailed images on TV screens can give the crew a realistic view of interplanetary space and Mars, getting progressively bigger as they near their landing site. The communications delay is similarly easy to replicate. It is also easy to stop a simulation should something go wrong. A previous mixed-gender isolation study was ended early when a Russian man tried to kiss a Canadian woman during a new year’s ceremony – many isolation studies since have been all male. By the same token, should any participants need to stop and leave the simulation they have that option. (Diego Urbina waits patiently to get to Mars.)

But an Earth-based simulation of a Martian mission is limited. There are certain aspects of a mission that cannot be replicated on Earth, and some aspects of Earth that can’t be cancelled out of a simulation. This must psychologically affect the crew., and it seems like a real problem to me. How can a Martian simulation yield valuable data on the psychological stresses involved in a Martian mission if only some aspects of the simulation are realistic?

A simulation on Earth can’t negate the planet’s gravitational pull, which means the astronauts aren’t subjected to the same physical stresses of prolonged exposure to weightlessness a low gravity environment. An exercise routine on Earth will have a different effect on the astronauts’ physical fitness than the same exercise routine will in micro or Martian gravity. Living and moving in Earth gravity provides enough work on the astronaut’s muscles to keep them relatively strong during a simulation.

It’s easy to imagine that the physical physical effects of low gravity would have a psychological effect on a Mars-bound crew. If they arrive at Mars weaker than expected, they may have trouble lifting and moving supplies. If the transits between Earth and Mars are able to give the astronauts a low gravity environment, they may be fine on Mars but be too weak to walk on Earth; or worse, they might not have the strength to survive falling through the atmosphere during reentry.  (Left, Diego Urbina “walks” on Mars.)

The effects of isolation on eyesight could also be a potential source of stress and anxiety for t a crew. Our eyes adapt to our surroundings, so an astronaut who spends two hundred days in a spacecraft focussing only twenty feet in front of him will have a hard time focussing on the horizon when he lands Mars. This is a common experience for sailors after months spent in a submarine. They have a hard time focussing on the horizon when they surface.

The lack of familiar Earthly reference could add to the astronauts’ disorientation when they arrive on the surface. We use trees and mountains to gauge distances, but without familiar markers on Mars the astronauts could experience a confusing lack of expected sensory information.

There are also dangers associated with a Martian mission Earth-based simulations generally don’t replicate. In both the Mars 500 simulation and the Mars Society’s simulations – two week isolation tests that have the astronauts work outside in lieu of a Martian surface – there is no vacuum outside the astronauts’ habitat. A open door or a rip in a spacesuit doesn’t mean instant death during a simulation. Somewhere in the back of his mind, any participant in an Earth-based Mars simulation knows that there is no more inherent danger to his situation than what he experiences in his normal life. In fact, not having to drive to work probably makes living in an isolated Martian environment safer than most other professions. (Diego Urbina reenters the orbital spacecraft after his simulated Mars walk.)

In the same way, an astronaut in an Earth-based simulation knows he isn’t actually alone. For the Mars 500 participants, mission control was only sixty-five feet away even if the delay in communication added millions of miles to the apparent distance. On a real mission, of course, mission control will only be able to  If a problem arises, the astronauts will have to solve it themselves. A broken hatch in a simulation means nothing. A broken hatch in a mission makes a spacecraft fatally flawed.

It seems reasonable that each of these possible situations would affect not only each individual’s stress level, but the crew’s dynamic. Everyone reacts to a crisis very differently, and a crisis during a mission to Mars could lead to a power shift in the crew or irrational behaviour form individuals, which could in turn compromise not only the mission but the astronauts’ safety. This isn’t to say that the Mars 500 simulation and other long term isolation studies haven’t helped answer questions about what it will take to get men to Mars, and certainly doesn’t denigrate the time and effort of the six participants. But these types of simulations do raise questions such as: is there a best-case simulation to really prepare a crew to go to Mars? (The Mars 500 crew’s companion in the Martian lander – Hal 9000. That might be a source of stress and anxiety in itself.)

NASA has considered a trial Mars mission aboard the ISS (right). Simulating the communications delay, this would be a way for the organization to give its astronauts more autonomy in space. But this doesn’t take away the psychological effects of being close to home. NASA has worked since its inception to keep its astronauts safe. If a problem were to develop during the simulation, NASA wouldn’t sit back and let the crew die. It would reestablish real time communication with the ISS do whatever it could to get the crew home safely. This isn’t as safe a simulation as living in a controlled facility in Moscow, but it’s no more dangerous than the astronaut’s everyday job.

Other simulations have been done in caves, replicating the confined spaces and close quarters of a spacecraft. Long duration stays at the South Pole also tie in some aspects of a Martian mission – the isolation in a bland environment is probably the closest analogue to Mars on Earth. Biodomes and other small-scale outdoor self-contained habitats have been used in isolation studies – the Mars Society picked the bland winters in Northern Canada and the Utah desert as a Martian stand-in. But in all these cases the isolation was much shorter than the Mars 500 study – weeks instead of months – and certainly shorter than any possible voyage to Mars. (The Mars Direct spacecraft proposed by the Mars Society. It’s so small I can’t imagine anyone not going insane living inside it for 500 days!)

To create the reality of a do or die mission to Mars, a simulation would have to take place in a truly hostile environment. The men and women in control of the simulated mission would have to stand back and give the crew full autonomy. Help in any emergency would have to reach the crew with the appropriate time delay and only through the connections mission control will have with a spacecraft en route to Mars. If an astronaut falls ill, the crew will have to deal with it. NASA won’t be able to send a doctor to a spacecraft halfway to Mars. (Mars, without an Earthly marker in sight.)

The best Mars simulation I can envision would have the crew make the “voyage to Mars” in a submarine – the best stand-in for the isolation and danger of living in a pressurized cabin in deep space. Daily bedrest would mimic the effects of microgravity on the crew’s muscles. The “Martian landing” would have to be in a bland Martian environment such as the Antarctic. A return to the submarine for the “return to Earth” Would round out the simulation.

But a necessary part of any more realistic simulation would be an agreement between participants and administrators that nothing (save a life-threatening emergency) would stop the simulation. NASA can’t guarantee its astronauts safety in space, Should guaranteed safety be part of a simulation designed to test a crew’s psychological reactions to spaceflight? (Right, Wang Yue during a bed rest experiment.)

There are, of course, endless problems with this kind of simulation from logistical to ethical considerations. It’s highly unlikely that a true analogue mission to Mars will ever happen on Earth, and certainly would never with the endorsement of any government organization. Simulations and studies will likely address different aspects of proposed Martian missions, piecing together the challenges facing a Mars-bound crew.

It will be interesting to see what data the Mars 500 study yields – so far, some jealousy among between crew members is the only negative report. As post-mission medical and psychological tests are administered and the results released and as the participants return to their families and normal lives, we will start to see the possible long-term effect of long-duration spaceflight. In any case, the study will certainly answer some questions and will possibly raise even more.

Earth as seen from Mars. That's a long way home.

Suggested Reading (in addition to in-text links)

Mars 500 Quick Facts.

Mars 500 Crew Diary.

Mars 500 Overview.

i09 Article also suggests the Mars 500 mission doesn’t prove men are psychologically ready to go to Mars.


3 thoughts on “The Problems of Simulating Mars on Earth

  1. The most logical way to test how well astronauts adapt during a long voyage to Mars would be to test the crew first in a shielded space station at one of the Earth-Moon Lagrange points for the duration of a journey to Mars. The Lagrange points will probably be the logical point of departure for a manned interplanetary spacecraft anyway.

    After about six to eight months, the crew should be transported to the lunar surface to stay at a Moon base for a few months– simulating a stay on Mars. The crew should then be transported back to the Lagrange station for another six to eight month stay simulating the return to Earth. Then they should be actually returned to Earth to see how well they’ve held up physically.

    Such a test may seem exhausting! But this is nothing compared to actually sending a small crew to Mars and back!

    The Lagrange point station and the interplanetary vehicle may have to be configured to produce artificial gravity in order to avoid the deleterious effects of microgravity environment.

    But the appropriated amount of radiation shielding is going to be the most significant factor. If the human brain has to be shielded from heavy nuclei in order to avoid potential brain damage then the vehicle is probably going to require several hundred tonnes of mass shielding.

    Marcel F. Williams

  2. Marcel has good ideas. I would add, to the Lagrange point – lunar expedition – return to Lagrange point simulation, a differential gravity simulation, in which the Mars surface duration of a real mission is simulated at Mars gravity. Obviously, this would have to happen at the Lagrange station, or in Earth orbit, using centrifugally-produced (or should I say centripetally-produced) artificial gravity. The simulated Mars surface portion of the experiment would be a lot more boring than a lunar expedition, but would simulate the gravity demands accurately.
    One of the greatest questions which will need to be answered, before humans cross interplanetary differences, is what minimum gravity field people need to remain healthy for indefinite periods of time. Obviously, ISS crews can survive 6 month periods at zero-G, and a Mir cosmonaut survived same for over a year. All of the above have adapted back to life at 1 G. But, are there long-term health effects? Will their bones ever recover their former density? Does decalcification ever totally reverse? Do these ill effects of zero-G occur at 1/6, or 1/3, gravity (maybe just at a slower rate)? If so, then we’ll never be able to colonize the Moon or Mars. We need an orbital centrifuge facility to answer these questions once and for all.
    One intriguing thought: Is there some subset of 1G which has beneficial effects for humans, long-term? Maybe our skeletons develop arthritis less quickly, or not at all, in zero=G. Maybe our skin and muscles maintain better elasticity, and our vertebral discs stop wearing out, at lower G levels. If so, fractional-G, space habitats will be very popular residences for celebrities sometime in the future (another potential commercial space market?).
    As for radiation shielding: why wouldn’t a double-walled hab, with water filling the interstitial space, work? Lighter than conventional lead shielding; and astronauts will have to bring water with them anyway. Why not solve the shielding, and H2O storage problems, with one stone?
    Finally: I wouldn’t go insane living 500 days in the proposed Mars Direct habs – not even in a Dragon capsule, which Dr. Zubrin proposed as serving the functions of MTV, hab, and ERV of his latest manned Mars mission concept (which uses SpaceX’s proposed Falcon H boosters, and Dragon capsules, for a near-term round-trip Mars manned Mars expedition). In fact, I volunteer to go on the first trip!
    -Stu Young

    1. Oops. I meant “interplanetary distances,” not “differences.” I should have been more alert during my cursory proofread.

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