Human Factors in Mars Research: An Overview
This paper reviews some of the human factors considered important for a human mission to Mars and for research leading up to such a venture.
A manned mission to Mars present unique challenges from a technical/engineering perspective but also from a human factors point of view. How will the combination of several months exposure to microgravity followed by the .38-g Martian gravity impact the crew? How will the harsh Martian environment and increasing delays in communications impact upon individual crew members and their performance? What man-machine systems are uniquely relevant to a manned Mars mission eg. work saving systems for recording and retrieving data, control of semi-robotic explorers. What habitat design is most suited to crew comfort and productivity? What health issues for the crew are likely to be encountered (eg. bone health within a closed food system, potential exposure to chemical hazards, exposure to increased radiation)? How should workload be managed, given there will be ‘so much to do with so little time’. How should the right crew be selected and what group dynamic pressures will they encounter?
The Mars Analogue Research Stations in several international sites are already examining some of these questions. Human factors research at the proposed Australian site, MARS-OZ, will seek to build upon previous Mars relevant studies while adding new projects not previously conducted. In addition, several other MSA projects have human factors components worthy of exploration. These include the MarsSkin spacesuit, the Mars Analogue Helment Systems project, the Tools and Applications for Martian Exploration and Research (TAMER) and the Marsupial Analogue Rover Project.
Several categories of human factors research is proposed for examination of potential problems and design of effective countermeasures in relation to human exploration of Mars.
Crucial to any human mission to Mars are the various biomedical and psychological issues likely to confront the crew on such a long and arduous mission, often understood collectively under the term Human Factors. A detailed understanding of relevant human factors issues is required in order for any planning process towards a Mars mission to be adequate.
The current paper does not have the scope for an exhaustive coverage of each area of human factors research related to a Mars mission. Instead, an overview of the most relevant issues, roughly in order of priority, is undertaken with reference to a sampling of the relevant literature. Some of the material is taken from popular magazines such as National Geographic and Discover, particularly where excerpts from interviews with astronauts and scientists appears the best way to represent the human factors issues of concern.
What happens to the human body during prolonged space flight and what is likely to happen during the longest mission yet, a flight to Mars? Much is already known about relatively long space missions and their impact on the human body but a Mars voyage is likely to involve at least six months travel each way in microgravity conditions and more than 12 months on the surface in a .38 of Earth gravity environment. Figure 1 outlines the changes in some body systems known to take place during prolonged space flight.
FIGURE 1 - Changes and Adaptation to Physiological Systems in Microgravity (NASA Bulletin on Spacelab Life Sciences, No 1, August, 1989)
The table below, from a study by the International Astronautics Association (1997) summarises in greater detail the impact of prolonged spaceflight both during the flight itself and after the flight has ended.
TABLE 1 - Potential Medical Consequences From Long-Duration Exposure To Space Flight Factors (IAA, 1997)
Bone density loss
In a microgravity environment 1-2% bone density loss per month is common but up to 5% per month loss can occur in weight bearing bones, particularly the os-calcis (heel) bone. On earth, our bones are constantly renewed: old bone is absorbed (osteoclasts), new bone is formed (osteoblasts). In space there is almost no renewal. "It's like a million Pac-men chomping away", according to Adrian de Blank, a professor at Baylor College of Medicine. During a mission to Mars, a 45 year-old could see bone deterioration reach the weakened state of severe osteoporosis (Long, 2001).
Bone density loss possibly arises from atrophy of large weight bearing muscles. "The weakened muscles exert lesser torsion and compression on bones, which initiates a little understood process that drastically reduces bone renewal." (Long, 2001). One theory is that removal of physical/mechanical stress as well as changes in muscle action may result in alteration of stress generated by piezo electric forces occurring at the molecular level. Other factors felt to contribute are direct changes in bone cell metabolism and changes in vitamin D, humoral and bone derived growth factors which play a complex role in bone formation and maintenance. (ISU, 1991). Head of the bone loss team at the National Space Biomedical Research Institute (NSBRI) is Jay R. Shapiro, professor of endocrinology at the Uniformed Services University in Bethesda. He states, "You’d better have 100 percent of your bone and muscle when you land on Mars. If you can't protect yourself on the way up, the risk of fracture is a very big deal." (Long, 2001)
Other physiological changes
In a microgravity environment "body fluids surge to the chest and head, puffing the face and shrinking the legs. The body responds by excreting fluids containing sodium and calcium; red blood cells decrease, leaving astronauts anaemic. The heart enlarges and then shrinks; spinal disks expand; cells can lose structure. The immune system and support muscles weaken. Sleep patterns are disturbed, for reasons not understood, limiting astronauts to six hours of sleep a day." (Long, 2001)
Expansion of spinal discs results in lower back pain and discomfort for astronauts and is likely to be a more significant problem on a prolonged journey.
There is also evidence for suppression of the immune system in microgravity, the evidence including alterations in lymphoid organ size, decreased lymphocyte activity and changes in interferon production (Sonnenfeld, 1990). Factors felt to lie behind these changes include altered physical and chemical interactions such as diffusion kinetics and changes in ion concentration at the molecular level. Physical and psychological stresses experienced during space flight may also act to suppress immune function, while complex interactions between the altered cardiovascular, muscular skeletal, hormonal and neurovestibular systems may also contribute to immune suppression. (ISU, 1991).
Disturbed neurovestibular & cognitive function
The vestibular system is located in the middle ear and consists of the utricle, saccule (otolith organs) and semicircular canals; the latter measure linear acceleration and orientation of the head to the gravitational sector. The three semicircular canals signal angular acceleration of the head in the three directions of rotation: pitch, yaw and roll. In microgravity the gravitational reference point is lost and conflicting information can be received by the otolith organs, semicircular canals and visual system causing visual illusions, disorientation and nausea. A typical example of the effects is space adaptation syndrome which affects more than 50% of astronauts during the first few days of space flight and has been the subject of considerable study (ISU, 1991).
While space adaptation syndrome is temporary and can be treated with medical approaches such as scopalamine and amphetamine there is evidence for ongoing neurovestibular and cognitive difficulties associated with microgravity. Research indicates that humans perform more slowly in microgravity than on earth with evidence pointing to degradation in perceptual motor performance. This in turn is felt to be related to both the direct effect of microgravity on the central nervous system and also the non-specific effects of multiple stressors (Fowler, Comfort & Bock, 2000). A device with potential for restoring spatial orientation in microgravity is the Tactile Situation Awareness System developed by flight surgeon Dr Angus Rupert (Rupert, 2000). This system uses a matrix of mechanical tactile stimulators applied on the torso and limbs to convey orientation cues in an intuitive fashion. Studies in both fixed wing and rotary wing aircraft have shown that pilots can fly complex maneuvers while blindfolded using this system with less than 20 minutes of training. In microgravity it may provide sufficient intuitive orientation cues to reduce nausea and improve productivity.
In deep space there is no longer any shielding from Galactic and solar radiation by Earth's magnetic field and atmosphere. Solar flares, otherwise known as coronal mass ejections, fling billions of tons of electrically charged gas into space and can inflict a lethal dose of radiation upon any spacecraft and its occupants in deep space. The primary countermeasure is early warning though sometimes no more than a few minutes will be available. Shielding devices are also been developed and a promising approach is polyethylene shielding as used to protect sailors on nuclear submarines. Water can also act as an effective shield against radiation and is incorporated into some designs for habitat/vehicle solar storm shelters.
Background cosmic radiation from the Milky Way and other galaxies is another potential threat. "Supernovae forge heavy ions-- atoms heavier than helium and short of electrons -- that bombard cells in a ranching pattern, causing breaks in DNA x-rays pierce like arrows. Both can cause genes to mutate." (Long, 2001). Francis Cucinotta, manager of space-radiation health research at NASA's Johnson Space Center notes that cosmic rays from Milky Way or other galaxies "pass through tissue, walloping cells and leaving them unstable, mutated, or dead. Understanding their biological effects is a priority." (Long, 2001). Potential countermeasures for cosmic radiation include dietary additives and anti-cancer drugs such as Tamoxifen.
A third source of radioactive exposure is any onboard nuclear power plant such as a nuclear thermal or nuclear Electric propulsion system used to propel the craft into the Trans-Mars Injection Stage (TMI), or a nuclear power plant for energy production at the Mars landing site. The Mars direct configuration would presumably avoid the latter difficulty, at least during the earth-Mars transit, in that a dormant nuclear plant would be landed by a supply ship ahead of a manned vehicle. The potentially lethal consequences of an unstable nuclear propulsion system is well illustrated in the novel "Voyage" by Steven Baxter.
For a variety of reasons, sleep is difficult in microgravity and may significantly, in turn, impair performance during transit to Mars with consequences for critical operations such as Mars Orbit Capture and Descent Stage. One area of research focuses on our "endogenous biological clock". In microgravity the circadian system is disturbed and specific countermeasures are required to avoid the negative consequences on sleep, mood and performance (Zulley, 2000). Fortunately, on Mars, the slightly longer than 24-hour day is in fact closer to our biological clock day and may not present real difficulty. Thinking towards a Mars mission envisages that, en route to Mars, the time would be used onboard the earth to Mars transit vehicle but, once on Mars, Mars time would be used for the Mars crew as well as for mission control back on earth.
The effect of microgravity on sleep quality and quantity is an area for further research in real or simulated microgravity environments while, in a Mars analogue setting such as MARS-OZ, a range of factors affecting sleep, including stress, can be examined.
One of the most studied countermeasures for biomedical problems caused by microgravity has been the use of vigorous exercise programs. The Russian space program with its history of lengthy missions aboard the Mir Space Station has accumulated considerable data supporting the use of exercise regimes, assisted by exercise bike's, treadmills, "penguin suits" and other devices. At the Institute for Biomedical Problems in Moscow, Inessa Kozlovskaya, a physiologist who has worked with cosmonauts for 25 years describes exercises developed in the early 1970s: a four-day cycle of bungee stretching and sessions on bicycles and treadmills. Yuri V. Romanenko, a conscientious exerciser, who landed after 329 days aboard Mir, later performed a one-arm handstand after being nagged by reporters. (Long, 2001).
Lower body negative pressure (LBNP)
LBNP suits are devices worn on the lower body and create a suction to pull the body fluids downward. The device, explains Dr Alan Hargens, professor of orthopedics at the University of California San Diego Medical School, prevents much of the loss of cardiovascular function and of muscle. It also seems to reduce bone loss (Hargens, et al., 1991). One reason is that the LBNP allows astronauts to exercise with an effective body weight between 100% and 120% of what they would feel on Earth (Murphy, et al., 1994). Another is that it restores the blood pressure gradient, increasing blood pressure to the legs. Hargens notes, "you can't just put high loads on the bone and then expect it to recover if you're not taking care of the blood flow to that bone as well." (Miller, 2001).
FIGURE 1 - Circa 1973, Skylab astronaut Owen Garriott lies in a Lower Body Negative Pressure device -- a big vacuum cleaner that simulates the effects of gravity on the lower body. Modern versions of the LBNP include a treadmill and self-generated negative pressure. NASA Photo ID: SL3-108-1278. Miller, K. (2001).
Dietary supplements such as oral phosphate and calcium have been found to reduce the hypercalcuria and urinary excretion of hypdroxyproline, byproducts of bone demineralization. Promising results have also been found with clodronate disodium, a compound used to prevent hypercalcuria during bed rest. Other possible therapies include fluoride additives to produce reversal of negative calcium balance and increase bone volume, while hormonal therapy used for osteoporotic patients also shows some promise (ISU, 1991).
The most promising countermeasure for dealing with a range of biomedical problems arising from microgravity is the use of some form of artificial gravity. Solutions include an entire rotating spacecraft using a habitat tethered to a used third stage rocket section as proposed in detail in the ISU study (ISU, 1991). One bed rest study showed that at least four hours of exposure to 1-g. with exercise is required each day to maintain a positive calcium balance (Schneider, 1987). A study involving partial weight bearing on the trabecular bone in rats suggested that bone formation may be equally well preserved with inertial acceleration of between .25 and .75 of earth gravity (Schultheism, et. al. 1989).
Researchers note that even partial gravity enables additional loading, which can in turn enable exercise in a context of compression forces on weight bearing bones, thus counteracting bone loss as well as muscle deterioration.
The ideal, as proposed in ISU 1991 and other studies, would involve a relatively long tether such that rate of spin is rather low (e.g. 2 rpm). This would mean that the corresponding coriolis forces would be negligible and almost certainly below the sensory threshold. Coriolis forces are the apparent force applied to an object appearing to move linearly within a rotating system and it will be felt by all objects not moving parallel to the axis of rotation. "Learning to live in such an environment may prove to be a challenge, and require adaptation training, since different forces and locomotion patterns are required for walking with, against, and perpendicular to the direction of rotation." (ISU, 1991).
In a Mars transit vehicle which utilises artificial gravity, transitions between various parts of the vehicle may lead to vestibular and biomechanical adjustment problems. These forces are proportional to the rate of rotation and are minimised if people move parallel to the axis of rotation.
TABLE 2 - Three Scenarios For A One-Way Trip To Mars: Severity Of Possible Biomedical Changes (IAA, 1997)
Legend: X = changes will occur; XX = changes more pronounced;
Preliminary studies have suggested that the rotation of the crew compartment on a long tether could produce 1-g at 1 rpm or less for an incremental cost of approximately 10% over the cost of launching a zero-g system. (IAA, 1997). There are however significant engineering difficulties with the design of artificial gravity spacecraft as noted in NASA’s Design Reference Mission version 1.0 (DRM 1.0). In this context, short radius centrifuge or SRC systems are becoming the focus of increasing research attention (Young, 2001). Current research on neurovestibular adaptation at NASA’s National Space Biomedical Research Institute (NSBRI), run by Dr Lawrence R Young, is investigating adaptation to SRC systems in order to investigate the coriolis induced side effects and to what extent adaptation to side effects will allow activity such as work in this type of environment. A current research facility is the Man Vehicle Laboratory at MIT, which has a bedlike contraption that rotates at 23 rpm to produce 1g on the occupants’ feet.
FIGURE 2 - Man Vehicle Laboratory at MIT: a bedlike contraption that rotates at 23 rpm to produce 1-g on the occupants’ feet. (Man Vehicle Laboratory, Artificial Gravity Homepage)
A recent innovative system known as the "Space Cycle", simultaneously provides exercise, impact loading and a degree of ‘human powered’ artificial gravity and is undergoing trials for possible use on the ISS. One or two crew members pedal themselves about a shaft contained in the spacecraft, creating a short arm centrifuge with head to toe acceleration. Its developers argue that the advantages include reversal of fluid shift to the head, minimization of postflight orthostatic intolerance (feeling faint when moving from sitting to standing soon after spaceflight), pedalling to maintain muscular and cardiovascular fitness and enhancement of skeletal homeostasis by impact loading. Motion sickness is controlled with restraints and virtual reality headsets. The main disadvantage to the Space Cycle is its size, the device when operating being roughly ten feet in diameter. Also, the Space Cycle can create unwanted vibrations in the spacecraft, although vibration dampening for the system is being investigated.(Kreitenburg et al, 1988).
FIGURE 3 - Space Cycle; Sources: Left: Cook Bros. Racing (2000) Right: Tour De Space (2001)
The main difficulty overall with variations of artificial gravity and particularly SRC designs appears to be the coriolis effects leading to neurovestibular side-effects such as nausea and illusory body tilt sensations, particularly when one is attempting to move around and work in such an environment.
One potential solution is to have a relatively small cross-section of the Mars transit vehicle capable of rotating at sufficient RPM to produce at least Mars gravity. This would yield short radius centrifugation incorporating a radius of 2.5 to 4 m, depending on the spacecraft design (e.g. biconic versus tuna can). This section of the spacecraft could be used exclusively for sleep such that the astronauts sleep in a partial gravity environment, providing up to eight hours per day of artificial gravity with its accompanying benefits without the neurovestibular side-effects associated with attempting to move and work in this environment. Such a design is likely to also yield much better sleep quality with resulting improvements in performance during waking hours. This approach could perhaps be combined with something like the "Space Cycle."
Life support systems and medical care
Both United States and Russian medical experience from space missions as well as evidence from analogue situations such as Antarctica, submarines and oil rigs suggest there is a high likelihood that medical problems will occur during a long-term space mission such as a mission to Mars. Major health issues may include incapacitation due to decompression sickness, kidney stones, radiation exposure and life support malfunction. In the event of such incidents the medically trained crew members of a Mars mission will need a high degree of autonomy and self-sufficiency due to the response time lags in support from Earth. The use of some form of expert system with a large database of diagnostic and procedural knowledge is likely to be required as well as virtual reality training techniques.
Another issue is that the absorption and effectiveness of certain drugs in a partial gravity environment may be quite different to that found in earth gravity. "Data on fractional-g drug absorption and appropriate drug dosages must be acquired, possibly from lunar base experiments, and that data must be used to plan the treatment of illness and trauma." (IAA, 1997). Surgical techniques in a microgravity and partial gravity environment also need to be established, perhaps through research on the ISS and also on a lunar base. Medical equipment which works effectively in zero-g as well as partial gravity needs to be proven through research in similar environments.
Crew interaction and isolation
Perhaps greater than any of the challenges for a human Mars mission considered so far is that of human interaction in what will be an ‘isolated and confined environment’ on a scale not previously encountered. An article in the Discover website by William Speed Weed (2001) entitled "Can We Go To Mars Without Going Crazy?" notes that most of the warnings about a Mars trip have come from astronauts who spent months aboard Mir.
"When the first Mir astronaut, Norm Thagard, returned to Earth in 1995, he told debriefers that psychological challenges were the toughest part of his mission. The last Mir astronaut, Andy Thomas, says that without intense efforts to solve the psychological problems of a group of astronauts confined to a small space for months, "the mission will fail." Russian cosmonaut Valery Ryumin says succinctly, "All the conditions necessary for murder are met if you shut two men in a cabin and leave them together for two months." Thomas says each astronaut will "have to be strong enough to deal with what you perceive as"- he pauses here to be diplomatic- "not imperfections, but differences between you and them.""
In an interview for National Geographic magazine, Thomas described an experiment involving six astronauts confined to a 12ft square room for 1 week. "If you give them little to do, stress can be achieved in a couple of days…. It can be extremely difficult." The goal of the exercise was for astronauts to manage themselves, pull together, structure time so that individual and group needs would be met. According to Thomas, the exercise yielded a very positive response (Long, 2001).
Again from Speed Weed (2001): "Mars Flyer isolation chamber, Institute of Biomedical Problems, Moscow, Russia, December 31, 1999: During a New Year's Eve celebration held by the international crew, two Russian cosmonauts break into a fistfight, splattering blood on the module walls. The institute's mission control seals the hatches between the Russian crew's and the international crew's living quarters."
Recent observations in Mars analogue environments such as the Mars Desert Research Station (MDRS) indicate that traditional beliefs about crew interaction may not apply to a Mars mission: "The MDRS crews also debunked a number of myths pervasive in certain sectors of the space human-factors community. Specifically, the Mars Society had been advised that crews composed of 50:50 men and women tended to be unworkable and that having a non- American in command of an otherwise all-American team would be a very bad idea. However, the Mars Society operated three of the six crews with 50:50 male:female ratios, and two of the six crews had non- American commanders (one German man, one French Canadian woman), with good results in all cases. More traditional crews (majority male, American commanded) also worked well. Overall, the human factors results suggested that existing human-factors generalizations have very little validity, and that much more research and testing of actual crews in Mars analogue field stations is called for." (Mars Society Field Report, 2002).
A great deal more carefully designed research in Mars analogue environments (such as MARS-OZ) is required in order to learn effective ways to counteract the effects of isolation and confinement, particularly its impact on crew interaction. The personality of individual crew members as well as team competition will play a major role and is also an area for considerable further research (see below). Much of our understanding so far about the impact of isolation and confinement has come from studies from Antarctic expeditions.
One study of polar missions attempted to assign relative priority to the many behavioural issues affecting participants. Group interaction was found to be the most important of categories, followed by outside communications, workload and recreation. (Stores are, et al, 2000, Japan conference).
Speed Weed (2001) reported that: "One key factor to surviving such stresses [distance from earth, communication delay, isolation, etc] may be how different each crew member is from the others. Sociologist Marilyn Dudley-Rowley, chief research scientist at OPS-Alaska, an extreme-environments research firm, recently surveyed Antarctic and Arctic expeditions as well as Russian and American spaceflights. In her analysis, groups made up of similar people- white, military, American males, in one instance- had more interpersonal problems than did heterogeneous groups. People of different backgrounds, she says, have more to teach one another over the long haul than do people who are exactly alike. Thomas agrees: Even after months on Mir, he was still excited to learn Russian culture and language from crewmates."
In the same article space psychologist Dr Joanna Wood, who has been studying interactions between crew members in space analogue environments in Antarctica, notes that gender appears to be an irrelevant issue. All male teams as well as all-female teams and mixed teams appear to have functioned equally well from a crew interaction point of view in the Antarctic setting. Contributing to this research has been Dr Des Lugg, Head of Polar Medicine at the Australian Antarctic Division, now working for NASA in the United States.
Crew interaction monitoring and intervention
An efficient way of monitoring crew interaction has been developed by Russian psychologist and medical doctor Vadim I Gushin, Lead researcher at the Institute for Biomedical Problems, Ministry of Health, Moscow and Efimov Vladimir Avgustovitch, computer programmer and psychologist. The two researchers developed the PSPA – a test for the analysis of personal and intragroup attitudes (interactions) in a small group. The PSPA is a PC-based instrument which involves a brief questionnaire completed by all team members. Results can be produced and analysed very quickly, enabling speedy intervention for problems in team interaction and dynamics.
Similarly, in the USA, Dr. James Carter, a clinical psychologist at NSBRI’s Neurobehavioral and Psychosocial Factors Team and co-investigator Dr. Jay Buckey, Jr., are developing a computerized system designed to help people work through issues such as conflict resolution or mild depression. The prototype will include three modules for users - conflict management, treatment of mild depression and psychological self-assessment. The goal is to prevent these problems from occurring, but if they do, crewmembers will have the program on board to provide assistance. Carter notes "Researchers have shown that people are often more comfortable revealing sensitive information to a computer, rather than to a clinician, and they are more likely to acknowledge problems using computer-based assessments." (NSBRI News Release, 2002).
This is quite a different approach to that argued in ISU (1991) as well as by Canadian researcher Dr. Judith Lapierre. She spent 110 days in Moscow in 2000 as the only woman on a crew of eight (see section above), an experience she says taught her that astronauts will need personalized, one-on-one support to stay healthy during such long-distance trips. "In Russia, all the crew members have a family videoconference talk once a week, all crew members can exercise, all crew members can speak with a psychologist," she says (Lynch, 2002). Perhaps a combination of ‘quick diagnosis’ of problems, aided by computer analysis, and more personal intervention through psychologically trained crew is warranted. Further investigation at Mars analogue sites would be valuable.
Russian research suggests that team selection several years before a long duration space mission combined with years of training together can mitigate many of the crew interaction problems which are likely to develop in a stressful, lengthy mission.
Proponents of an international Mars mission such as ISU (1991) note that the cultural background of the Mars crew may significantly affect crew interaction. Language is obviously a prominent feature as found in joint American-Russian space missions and considerable effort has been required to overcome language barriers including the often quite different terminology and jargon used during space missions in different cultures. One study of Russian and American astronauts as well as mission control personnel concluded that, in future long duration space missions, countermeasures should focus on providing support for crew members from a culture in the minority and that crews should include more than one representative from each culture. (Kanas et al, 2000).
In an interview with journalist and Mars Society Australia board member, Jennifer Laing, Dr Andy Thomas noted that, during his long stay on Mir there was initial ‘cultural discomfort’ as the ‘visitor’ but that time and interaction did much to overcome this. Says Thomas: "It would be more accurate to say that the U.S. representative, as a guest, was initially unfamiliar with the Station, rather than being ill at ease." He notes that it took time to get used to the environment but points out that he felt life became less complicated the longer he was up there. "As the flight progressed, it actually got easier and easier." (Laing, ????)
The NASA DRM 1.0 advocates representation from nations who do not possess the infrastructure or significant involvement in current space endeavours such as the International Space Station. (NASA, DRM 1.0). One news item in response to the recent Odyssey spacecraft discovery of large quantities of water ice on Mars was very optimistic about a human mission being brought forward and advocated that the first person to set foot on Mars should be from the poorest nation in the world. Obviously there are political as well as psychological and social issues to be explored and a Mars analogue environment such as MARS-OZ would be an ideal location for this to occur. Already in Mars analogue environments such as the Mars Desert Research Station (MDRS) in Utah, assumptions about cultural mix for a Mars crew have been challenged. For instance a largely American crew led by a non-American for two different rotations of MDRS was found to be just as successful as those led by an American. Again, carefully designed studies involving teams incorporating a variety of cultural and personality backgrounds is called for and is quite feasible through MARS-OZ and other analogue sites.
A related issue to that above is, on what basis should a Mars crew be selected and what kind of training is required to facilitate a successful mission? The NASA DRM 1.0 emphasizes the need for autonomy and initiative for a Mars crew given that many of the scenarios that will be encountered on Mars cannot be rehearsed on earth and also because of the delay time in communications between Mars and mission control.
Characteristics advocated by NASA DRM 1.0 and ISU (1991) for individuals and teams likely to travel to Mars include the following:
Additional selection issues noted in the ISU (1991) study include:
The personality required for a Mars astronaut may be entirely different to those used in space missions so far. In relation to crew selection, Dr Joanna Wood notes:
"I'd want at least one person, but not more than one, who is really good at taking charge in a crisis. I'd want someone who is naturally a counselor, who takes care of other people's emotional needs. I don't want everyone to be like that. Then they'd get nothing done." She is also convinced that "for Mars, everyone's got to have a sense of humor about life. The trip is going to be full of surprises, and people who have rigid expectations are not going to be any fun." (Speed Weed, 2001).
Lawrence Palinkas, a medical anthropologist at the University of California at San Diego who also tracks behavior in Antarctic groups, evidently agrees. "People who are type A overachievers and extroverts, he says, are far more prone to depression and anxiety in close quarters than are quiet, self-contented personalities. His findings suggest that the ideal test pilot that NASA sought out in its early days would be a miserable, if not dangerous, choice for a Mars mission. Wood's work suggests that seven of them would be a catastrophe. ." (Speed Weed, 2001).
ISU (1991) recommends the following procedure for selection and training of a Mars crew:
1. Selection of individuals on the basis of their technical and interpersonal skill
2. Selection of three to five crews based on compatibility of individuals (indicated by psychological testing; would probably involve selection of crew members who have shared interests and compatible emotional needs; perhaps an argument for married couples.)
3. Group training in various analogue settings (e.g. MARS-OZ, Antarctica, ISS, lunar base)
Another issue to be considered is age of the astronauts at the time of a Mars mission. Current thinking is that astronauts generally reach their peak of productivity in their 40s and 50s. ISU (1991) argues for a training age in the 40s followed by a mission age in the 50s for the following reasons:
The concept of ‘fitness to fly’ has also changed with additional mission experience. For instance, it is now generally accepted in US space circles that less physically fit (though healthy) astronauts fare better in zero-g than their super-fit counterparts (Long, 2001).
Planning studies of Mars missions generally recommend that crew training allow for redundancy and involve cross training so that all necessary skill areas are ‘doubled up’ in the event of incapacity of one or more crew. For instance, the original Mars Direct model proposed by Robert Zubrin, involving four crew members, incorporates cross training for a pilot in engineering and mechanical skills and cross training of a mission specialist, say a geochemist, in medical skills. The ISU (1991) proposal involves eight crew members, mostly engineers with cross training in areas such as piloting, life-support, habitat maintenance, etc. The model incorporates two medical doctors with cross training in life science research and a scientist (e.g. geologist) who can also assist a medical doctor. This model also recommends, in addition to a medical doctor with psychiatry training, other specialists with high-level training in psychology, specialising respectively in group and individual intervention.
The model recommends an initial selection of individuals according to medical, psychological and specialty criteria followed by selection of teams on the basis of compatibility. Each team would then undergo a long period of training together, including training in group dynamics and cross cultural issues. Studies from Antarctic missions indicate that eventually a new social order and value system is created which gives meaning to and orders the behaviour of the crew and their social interactions (Panlinkas, 1989; ISU p120). Eventually a particular crew would be selected for the first human Mars mission with a second team serving as a backup crew and possibly the prime crew for a second mission.
Another component of the training according to this model would involve the ability to accurately perceive and respond to non-verbal communication. Other research indicates that perception of facial features and non-verbal communication can be significantly degraded in a microgravity environment (Cohen, 2000).
One issue which lends itself to research in analogue settings such as MARS-OZ, Devon Island and MDRS is that of command structure. That is, should there be a hierarchy of authority or a consensus approach to decision-making? For instance, the ISU (1991) study recommends a commander for Mission related issues and emergency situations but democratic decision-making for everyday decisions p 121. Some argue that a more military style command situation would cause resentment in a crew over a long mission and also be an unnecessary stress for the Commander.
Neuropsychological & medical monitoring of health & performance
Monitoring of performance as well as psychological and biological factors which influence performance is felt by many to be a crucial issue for a Mars mission, particularly given that the crew themselves will need to respond to any problems with limited backup from mission controllers on earth. The NASA run NSBRI has a team working on ways of identifying neurobehavioural and psychosocial risks to crew health, led by Dr David Dinges. The team seeks to develop methods to monitor brain functions and behaviour and counter measures to enhance performance, motivation and quality of life while also investigating leadership style, crew composition, organization and communication. Dinges, along with Dmitris Metaxas, a computer scientist at the University of Pennsylvania, is attempting to build a computer program that can recognize emotional states (Long, 2001). The research is attempting to train a computer to recognize facial expressions associated with human emotions. Some Russian research has involved monitoring of stress via voice pitch (Johannes, Petrovitsh, Gunga & Kirsch, 2000). This approach was studied over three years on the MIR space station but objections have been raised regarding privacy for astronauts, an issue relevant to many forms of psychological and performance monitoring.
Along with the PSPA test noted earlier, Russian researchers Gushin and Avgustovitch developed a PC-based technique for monitoring of human performance variables such as memory, and attention. The "Joy-test" consists of sub-tests measuring utilisation of working memory, eye-motor co-ordination, capability for arithmetic calculation under time pressure, logical reasoning and spatial orientation. The test yields overall measures of productivity (speed of work), reliability (error rate), and quality (precision) of performance.
Another brief neuropsychological battery is Cogscreen (McCallister, 1996) Jp16 . While this off-the-shelf product has been used in selection of pilot candidates for the US air force, ongoing use of brief screen batteries such as this one and the Joy Test can also be useful on a prolonged space flight, particularly where rapid detection of difficulties, quick interpretation and required intervention steps are readily available.
A third is the Spaceflight Cognitive Assessment Tool that crew members use aboard the International Space Station, developed by NASA psychiatrist Christopher Flynn. The tool tests an astronaut's response time and accuracy on a series of problems. "If an astronaut's score goes down, it warns him that he's off his game. Then he might make sure he gets some rest before he takes another space walk." (Speed Weed, 2001).
Manzey (2000) advocates repetition of screening tests and emphasizes the need for several criteria to be met in selection of such tests. These include:
The study suggests that the most sensitive monitoring measures are those of perceptual motor tasks such as tracking and tasks which place high demand on attentional processes e.g. dual tasks.
The Smart Medical Systems Team at NSBRI, led by Dr Geoffrey Sutton, seeks to use non-invasive smart sensors various aspects of crew health which can be also indicative of stress eg. raised blood pressure. Researchers have found that stress can be monitored by measuring levels of the hormone cortisol in saliva while Dinges also notes that computers can already monitor immediate health clues such as blood pressure, heart rate, restoration and sweat gland activity. (Speed Weed, 2001).
In 1974 onboard Skylab, three US astronauts were each day given a 6 foot long sheet of instructions; after a while, to get the most out of the investment, ground controllers even began scheduling experiments during the crew’s mealtimes. The crew finally rebelled and commander Gerald P. Carr announced the crew was on strike, that from now on they were going to look out the windows, take pictures, etc. "Stunned controllers got the message and finally concluded that astronaut time off was "mandatory" and "inviolate". (Long, 2001).
NASA has clearly learned a great deal about human performance limitations and time scheduling since the days of Skylab. In its DRM 1.0 NASA outlines a Mars surface mission time allocation which, relatively early in the surface day, following 90 days of site preparation construction and verification, includes a full week off duty for the crew. The time scheduling also includes eight hours per day of sleep and sleep preparation, one hour per day of recreation and exercise and one hour per day of hygiene, cleaning and personal communication.
Clearly, there needs to be a balance between accomplishment of mission science, engineering and other objectives with the personal needs of the crew. Mars analogue environments such as MARS-OZ provides an ideal setting for testing out scheduling of various mission components such as work and leisure under simulated Martian conditions.
Another area which lends itself well to study in a Mars analogue environments is the complex interaction and interface between humans, autonomous and semiautonomous robotic explorers and other machinery. Early thinking about interplanetary missions has tended to take a "robot vs human" dichotomous approach but, in more recent years, more integrated concepts in which humans work in close interaction with robots is being preferred.
Research on telepresence and virtual reality means that, during Mars surface exploration, robotic ground or even airborne vehicles could conduct more difficult and dangerous exploration missions with a crew member in the habitat being virtually present in the vehicle and having complete control through teleoperation technology.
The IAA (1997) study notes that human factors engineering is essential to successful human space flight and exploration. "Major challenges in this area related to a piloted mission to Mars include:
Human factors engineering evidently now shares equal status with other branches of engineering in relation to habitat design of the International Space Station. Similarly, it needs to be given appropriate priority in the design of a human habitat for the Mars transit and a Mars surface habitat.
An architectural design team at the University of Wisconsin has given considerable thought to the various human factors issues in design of a permanent Martian base in their paper "Space Architecture for the First Human Habitation on Mars" (Huebner-Moths, Fieber, Rebholz & Paruleski, 1992). The authors note that a substandard physical environment leads to dissatisfaction while physical comfort and safety in terms of noise control, proper ventilation and lighting also contribute to productivity. Design requirements advocated by the authors for a Mars habitat are:
One specific issue is zoning of spaces into areas such as individual/private, small group/semiprivate and group/public. Another relates to changeability through modular structures, replaceability and expandability. The authors note that the work environment must be safe, the astronauts should be able to personalise their workstations, the work environment should be properly lit and adequate ventilation should be provided.
The IAA (1997) study notes the close relationship between system design in habitats and crew health. "Contaminant and hazardous substance concentrations are potentially toxic threats in the recycling of breathable habitat atmospheres, water recycling systems, and solid waste handling and recycling systems in spacecraft and Mars bases. For example, thermodegradation of teflon wire insulation in spacecraft can release toxic gasses and ultrafine particles that are irritating and possibly life-threatening to habitat crews. Water recycling systems that use iodine as the disinfectant may give rise to iodinated byproducts (IDPs) which have potentially debilitating and long-term health effects. Prolonged, low-level exposure to toxicants has a potential to induce behavioral changes."
The study notes that, once on Mars, the intrusion of Mars surface and atmospheric materials into the habitats represents an unknown risk at this time. Some understanding, however, of the impact of dust on EVA suits and habitats is being gained at Mars analogue sites such as MDRS, Utah.
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