American Military University SPST619 The Psychology and Physiology of SpaceMission to Mars: The Human Perspective BY Carl Lee Tolbert Student ID # 4172687 16 June 2012 CONTENTS Scenario……………………………………………………………………………………...……3 Temperature Extremes……..……………………………………………………………………3 Extravehicular Activity................…………………………………………………………3 Circadian Dyssynchrony………………………………………….………………………..……5 High Vacuum………….................…………………………………………………………….…7 Effect of Vacuum on the Human Body…………………………………………...……….7 Ionizing Radiation………………………………………………………………………...……...8 Radiation Countermeasures………………………………………………………..…….10 Micrometeoroids and Space Debris……………………………………………………..…….12 Plasma Interaction……………………………………………………………………...………12 Microgravity……………………………………………………………………………...……..13 Sensing Gravity and Space Motion Sickness……………………………………….……13 Muscle Atrophy……………………………………………………………….…………15 Bone Loss………………………………………………………………………….……..16 Muscle and Bone Loss Countermeasures………………………………………………..17 Cardiovascular System Damage…………………………………………………………18 Cardiovascular Countermeasures……………………………………………..…………20 Psychological Factors…………………………………………………………………..………20 Pre-flight Preparation…………………………………………………………...………..22 Summary and Recommendations……………………………………………….……………..24 The “Show Stoppers”………………………………………………………...…………..24 The Minutia………………………………………………………………………………24 Need for Further Research on New Experimental Fronts………………………………..25 Final Recommendation…………………………………………………………………..26 Notes…………………………………………………………………..………………...…...…..27 Works Cited………………………………………………………………………………......…35 2 Scenario This paper is in response to the following hypothetical scenario: The President of the United States must make a critical decision – whether or not to start the mission planning process needed to send astronauts on a 2.5-year round-trip journey to explore the planet Mars. You have been tasked to write a paper for the President, introducing him/her to the physical and mental challenges of human space travel and exploration. The response to this scenario is a broad topic that is better served by dividing up the information into several smaller sections, with a summary at the end to bring the information back together. The divisions will consist of the following: temperature extremes, circadian dyssynchrony, high vacuum, ionizing radiation, micrometeoroids and space debris, plasma interaction, microgravity, and psychological factors. Temperature Extremes To gain an understanding of the extremes in space, consider the common astronaut’s experience of a spacewalk from a spacecraft in low earth orbit (LEO). The spacecraft in question is traveling at a speed of Mach 25 (around 5 miles per second) and circles the earth once every 1.5 hours.1 Inside the spacecraft, the ambient temperature is 69.8 to 73.4*F (21 – 23*C), as opposed to the extreme temperatures of -212 to 212*F (-100 to 100*C) found outside the spacecraft.2 In addition to the mechanical wear and tear on the outer hull of the spacecraft, the primary challenge related to the extreme temperatures of space appears when astronauts need to venture outside. Extravehicular Activity As with the trip to Mars, it is imperative that the deployment of a spacewalk, also known as an extravehicular activity (EVA), is operationally planned and that emergency procedures are 3 8 The passive heating design becomes problematic when temperatures inside the suit drop lower than expected because the suit can only decrease cooling and the temperature is slow to increase. The workload accounts for 800-1500 calories burned per hour during the EVA deployment. The hands of the astronaut are of specific concern in the extreme temperatures. the astronauts have very specific medical and environmental concerns.7 It is important to understand that although the suit design provides for active cooling.)11 Note – A right to left shunt is a genetic 4 . the work is arduous and generates 10 – 20 times the heat of a crew member at rest. including heat stress and heat stroke. simple functions like loosening a bolt must be planned beforehand because any force applied through the tool to the bolt will send the crewmember hurtling through space unless the optimal tethering or holds are utilized.5 With microgravity. With a typical workload of up to several hours performed outside the spacecraft.3 This very draining work may exacerbate the already-deconditioned state of astronauts via increased heart rate and possible dehydration. If the generated heat exceeds the suits ratings during an EVA. and paralysis. and provisions must be made for their individual active heating and cooling. heating is passive based on body temperature.10 Type II DCS (the more severe version) can cause stroke.6 As mentioned earlier. including specially made thermal mittens. vestibular stress.4 One of the other observed aggravations is irregular heart rhythm during the EVA and during post-flight recovery. established when required. especially from a right to left shunt (a genetic bridge that can allow bubbles to move from the venous system to the arterial system.9 Decompression sickness (DCS) is also a concern for EVA deployments because any change in atmospheric pressure surrounding the body could cause nitrogen bubbles to form in the blood and tissues. then physiological hazards become a possibility. defect that cannot be fully screened out and is present in 15 – 20% of the population.16 Lastly.14 Note – The pressure inside the two different types of suits deployed for an EVA are 29. researchers believe that fitness and cardiovascular training are useful. The crew member would also need to be evacuated and possibly treated by a hyperbolic chamber on Earth. on a trip to Mars. astronauts can experience 16 sunsets and sunrises per 24 hour period.19 5 .” in little time and also acts a preventive measure (pre-breathing) to reduce nitrogen levels. type II DCS will have potentially deadly consequences due to the lack of treatment options and evacuation plans. considering the LEO example mentioned earlier.17 Circadian Dyssynchrony Again. then the crew member would be treated again with 100% oxygen and the drug lidocaine. Obviously. such as the “bends. In addition to the countermeasures mentioned. The good news.12 Exposure to 100% oxygen usually clears the less severe symptoms. pre-screening for predispositions to specific issues associated with EVA is warranted as well.18 Natural sleep patterns (circadian rhythms) can be disrupted on missions conducted in LEO and the proposed Mars trip based on light/dark irregularities and other factors.13 If type II DCS is diagnosed.5 kPa for the NASA extravehicular mobility unit (EMU) and 40 kPa for the Russian Orlan space suit.15 It makes sense to decide which type would be the best to use in order to consolidate training and operations for EVA deployment for the trip to Mars. however. is that there have been no reported cases of DCS in American astronauts since Gemini. monitoring nitrogen levels and other factors will aid the crew in the safe and effective deployment of any EVA endeavor. based on the history of space flight. it is obvious that people are statistically sleep deprived in 6 .5 hours of sleep. disruption occurs.23 When astronauts perform their duties.21 Researchers have determined that circadian functions are found in almost all organisms and are located in cells. reduced waking cognitive performance. organs.29 The long-term effects of sleep deprivation can include obesity and type II diabetes. and electrical fields.20 The primary synchronization method concerning the trip to Mars is the circadian clock (the molecular-level mechanism that prepares the life form for pre-emptive environmental stimuli/events). temperature.5% of respondents reported an average of less than 7. diet.28 Other corollary short-term effects can include irritability and a weakened immune system. mean = 57 years for women and 58 years for men) determined that 52. sound (60 dBA average on spacecraft). Humans and other life forms on Earth have developed several mechanisms that allow synchronization between the life form and the environment. even everyday activities.24 25 The loss of synchronization with the environment can create many short-term and long-term functional and medical problems for astronauts.22 Circadian clocks have been found in almost all organisms investigated to date. tissues. and elsewhere.26 The most challenging short-term effect of circadian dyssynchrony is a lack of natural sleep. and reduced behavioral alertness. with a few notable exceptions. The disruption of the circadian function can be caused by light.30 In modern society. Researchers equipped with a very large database of 1. light flashes (corona discharges are seen even with the eyes closed while in space). which go against the natural rhythm of the sleeping and waking process. movement/physical activities.27 The effects of sleep deprivation include oculomotor activity (eye movement changes).116 million Americans (age ≥30 years. and the astronaut’s blood does not boil. an explosive noise can be heard. gas expansion does create a problem if the breath is held because the lungs can be damaged. it is imperative to maintain proper operations so that astronauts during the Mars mission have optimal natural sleep. which created a rapid depressurization of the space station.54 kPa (14. however. High Vacuum The vacuum outside the spacecraft is severe and naturally poses a deadly hazard for unprotected astronauts. such as the spacecraft opening up unexpectedly to the vacuum of space. however. The astronaut does not freeze.32 No crew members were hurt. complete with operational protocols. the accident shows the need for absolute safety and emergency procedures for the trip to Mars. must be maintained for operations that can expose the inside of the spacecraft to the vacuum of space. The research consensus is that the survivability of an unprotected astronaut would be 5 to 15 seconds for the astronaut to help themselves clear the hazard or up to 90 seconds for others to remove the astronaut from the hazard. their normal lives.35 This type of event is significant different that exposure to vacuum via a slow leak in an EVA glove.34 Explosive decompression is a far more deadly circumstance than those mentioned above.7 psi) for an optimal crew habitat. When two different air masses come into contact. normalized pressure is maintained at 101. the space station Mir collided with a supply module.33 Many myths surround exposure to the vacuum of space. Inside the spacecraft. In 1997. The mechanical 7 .31 Great care. however. Effect of Vacuum on the Human Body Most of the data associated with exposure to vacuum comes by the way of human accidents or animal testing. Free radicals can and will disrupt and harm other molecules. such as DNA.38 Ionizing radiation takes place at the atomic level and is divided into two forms based on the type of radiation. like protons and neutrons. with the exception of Apollo. like x-rays and gamma rays. Another way to measure the magnitude is by measuring the energy that is 8 . especially since all human space missions have been within 600km of the Earth. and burns. The magnitude of the high-energy radiation can be quantified in electron volts (eV).42 Medical x-rays are measured in thousands of eVs. the excess electron (free electron) is ejected. the more damaging the radiation can be to molecules. and magnetic field.40 A free radical is created from the resulting ion or free electron.36 Ionizing Radiation The key to understanding radiation hazards aboard spacecrafts is to understand the basics of radiation on earth and beyond earth’s protectionary boundaries and the ways radiation can affect human physiology. hypoxia. expansion of gas in the body during decompression can affect the gastrointestinal tract and the lungs and can create DCS.39 Basic particle physics dictates that when an ion is created by energy bombarding an atom. The first form of radiation is photon-based.37 The idea of creating shielding from radiation beyond Earth’s boundaries creates a significant challenge for spacecraft designers and the space crew that will be operating the spacecraft. The earth has natural protection from radiation based on the earth’s mass. and the second is particle-based. atmospheric layers. whereas cosmic radiation is measured in millions of eVs.41 The higher the energy level in the ionizing radiation. )46 The damage this type of radiation produces in cells is directly proportional to the atomic number of the particle of radiation and has a high LET. decrease in blood cells counts (weakness. Although research and modeling has improved over the last 40 years in terms of space weather prediction.43 Particles like photons can create more ionization based on the distance travelled and when the particle stops.47 Long-term damage can include sterility. and infection). The acute damage from radiation and radiation sickness-induced nausea and vomiting includes skin effects. with high charges and high energies (1020eV. it is essential that any Mars trip have adequate prediction models. 12% alpha particles (helium nuclei). The measurements are called linear energy transfer (LET). the fact remains that there are only a few minutes of warning before a solar event. cancer in 9 . the storms happen quickly and can bombard the spacecraft and any space crew members outside the inherent shielding of the craft (EVA). Note – Since the prediction models for solar events need to monitor both sides of the sun. based on dosage. anemia. distributed through the cells by the radiation. Solar flares present a specific catastrophic form of radiation that astronauts and spacecrafts can be subjected to. the graying and loss of hair. acute and long-term damage.44 Even with planning and prediction. This stopping event can also affect other nuclei and lead to secondary damage.45 Galactic cosmic radiation is the constant flux of high-energy radiation that is always present in space. eye lens opacification (cataracts). and 1% heavy nuclei ions. Galactic cosmic radiation consists of 87% high-energy protons produced by the nuclear disintegration of stars and secondary neutrons. and the loss of non-dividing cells. ranging from lithium to iron. HZE. Physiological damage from ionizing radiation can be divided in two overlapping categories. 53 54 The passive shield designers must take the secondary radiation into account. 10 . from various sources.7 µSv per hour. The National Council on Radiation Protection and Measurements (NCRP) estimates that 2 g/cm2 of aluminum and.55 The consensus. The major challenge is that not all radiation is deflected by any one type of material. as well as the weight and onboard space (room) design constraints. while astronauts average a total dose of 1 Sv in their careers.3 to 5. based on cosmic events. which researchers have observed to be more detrimental to astronauts than primary radiation in some cases. shielding up to 50 g/cm2 are required for basic protection. and spleen). meaning “braking” in German. some radiation that is absorbed can produce secondary radiation.51 A round trip to Mars will expose crew members to an unacceptable level of 5 Sv.005 Sieverts (Sv) annually.3Sv per year.49 Commercial airline pilots are exposed to .)48 The average human on Earth receive a dose of less than . colon. away from the Earth.50 Crew members onboard the international space station (ISS) receive . the blood-forming organs (the bone marrow. As humans travel higher in altitude. stomach. and furthermore. also known as bremsstrahlung. thymus. The solution for a passive radiation shield seems simple from the cost and deployment perspective. and genetic effects that arise from cell chromosome aberrations and translocations (DNA strand break. is that conventional shielding will be inadequate for Mars travel on this practical point. in some cases. The idea is to create a wall behind which the astronauts are protected. and bladder. the dosage levels increase.52 Radiation Countermeasures Shielding is the primary means of protecting the astronauts from the harmful effects of solar and cosmic radiation and can be divided into passive and active designs. 60 Testing is moving forward and researchers believe a possible working model may be available at a later date. mass. The idea is to use super-conductors and a large enough power supply to create a magnetic field by utilizing the natural state of space. in addition to the atmosphere. emulating the one that surrounds the Earth in a dipole shape. which is plasma. 11 . and other more temperature-immune materials in search of a remedy for the problem. The second material is graphite nano fiber and other composites with specific densities and platelet (crystal) orientation. Active solar and cosmic radiation shields are being developed with multiple design approaches.58 Passive lightweight material shielding seems to be the most practical approach based on volume requirements. and current feasibility. This material is somewhat immune to secondary radiation because it is composed entirely of lightweight carbon and hydrogen atoms. Two materials should be considered for Mars travel due to the weight and mass constraints. boron carbide.59 The Earth’s magnetosphere. which can be the answer to the current solution of large amounts of water and metallic primary and secondary shielding sources but at a very low mass and weight. The idea of creating a magnetosphere is a serious design challenge. keeps most harmful forms of radiation away from humans. The first is a polyethylene-based material called RXF1.57 Researchers are hopeful that the ongoing experimentation and reformulations will produce an overall effective solution.56 The weakness of the material is temperature and flame retardation. Researchers have been using combinations of different types of carbon. One approach is to create an artificial magnetosphere around the spacecraft. boron nitride. no incidents of collisions or suit penetrations have been recorded so far. and are left over bits of asteroids and comets. The collision of micrometeoroids or space debris with the Mars spacecraft could be explosive. For the Mars trip (and any space travel).62 The resulting impact would be like a 35.63 The spacecraft traveling to mars will need to have adequate external shields robust enough to handle anything that the spacecraft cannot maneuver away from. plasma can be detrimental to the spacecraft and to astronauts performing EVA from an electrical discharge perspective.65 These “free” electrons and ions create plasma and are found in space.64 Plasma Interaction Plasma is the fourth state of matter and occurs when gas is heated enough (energy is great enough) to allow atoms to be stripped of electrons.000 or so pieces of space debris of significant size orbiting the Earth. the International Space Station (ISS) produces 160 VDC via the solar arrays and utilizes a distribution bus of 120 VDC (imagine a car’s 12 VDC battery system amplified 10 times. there is little fear of collisions after the spacecraft leaves Earth. For example. micrometeoroids are still a threat in free space.)67 The problem that plasma creates is based on the fact that the medium is super conductive.000 lb vehicle colliding with a wall at 118 mph. Imagine the kinetic energy created by a 1kg micrometeoroid colliding with the spacecraft at a velocity of 10 km/s. Micrometeoroids and Space Debris Although there are 12.68 Without the two plasma contactors (very different from the industrial contactors that switch 12 . however. however.66 It is easy to understand that space is a sea of plasma.61 Micrometeoroids are naturally occurring in space. The resulting interaction between the ISS and plasma is a stored -140 VDC charge. Note – EVA operations are especially susceptible to micrometeoroid damage due to the weak material that the EMU are made out of. In space. current loads for electric motors) acting as grounds. muscles.69 EVAs utilize a grounding tether so that during any work on the spacecraft or other devices in the plasma. the substantial negative charge would create arcing and be detrimental to the spacecraft electronics and personnel. the acceleration can be thousandths or even millionths of a G. such proprioception (sensors from joints.71 This very low acceleration in space is called microgravity and is also known by the incorrect term weightlessness. and tendons that give feedback regarding position) and vision. yield the orientation (gravity vector) to astronauts for balance.73 Linear and angular acceleration are detected and measured by neurovestibular organs located in the inner ear.70 Any spacecraft going to Mars will require a grounding arrangement like the plasma contactors (with redundancy) or other devices in order to allow safe interaction with the surrounding plasma.72 Nerves transmit this information to the central nervous system for processing and allow humans to determine orientation and position within the relative environment. the neurovestibular information can be augmented based on the environment and lead to misreading and inadequate responses by the 13 . On earth. the nominal rate is 9. combined with other inputs.75 In microgravity environments like space. Microgravity Gravity is the state of acceleration caused by the gravitational energy drawing bodies towards the center of the planet.8m/sec2. depending on the orbit. Sensing Gravity and Space Motion Sickness The neurovestibular system is primarily the body’s controls (organs) that sense the acceleration environment.74 These measurements. the astronaut will be protected from electrocution and burn damage caused by arcing. 80 Even in an environment that can induce SMS symptoms.76 SMS symptoms can appear over the first few days of travel. which is a lack of motivation to work and associate with others.85 14 . however. individuals vary in terms of susceptibility. and a general sense of lethargy. This hypothesis. Head movements can aggravate the symptoms. One of the consequences of the environmental changes on the neurovestibular system is space motion sickness (SMS).77 SMS can also lead to Sopite Syndrome.82 Fluid shift is based on linear acceleration. The idea that linear acceleration can be interpreted as head movement or body translation based on gravity is important to SMS. however. usually lasting three days after onset. the absence of gravity will cause a misreading of head movement versus translation.)83 The otoliths are crystals inside the saccule and utricle that ride on hairs suspended in a gel-type liquid. The theories are fluid shift theory and sensory conflict theory. stomach pains. and include symptoms like nausea. After recovery and adaptation. brain in terms of controlling balance and motor function. vomiting. crewmembers do not have reoccurrences of SMS.84 When the head moves. there is no adaptation for the 5% of individuals with chronic motion sickness. the mobility available to space crews in combination with microgravity creates an environment that can. is called Otolith Tilt-Translation Reinterpretation (OTTR).78 These symptoms themselves can limit the performance of the space travelers.81 Two major theories to account for SMS exist.79 Microgravity itself does not induce SMS. which arises in two-thirds of space travellers. Linear acceleration is measure by the saccule and the utricle (in essence how the head is translated with relation to gravity. which is debated. In microgravity environments. the crystals have a different inertia and yield a movement that is interpreted by the brain as linear acceleration. When the liquid inside of the canals moves. This movement is measured and then sent to the brain. angular motion is detected. have been successful with some subjects.98 The atrophy is characterized by reduced muscle mass and is mostly isolated to the postural muscles required for 15 .86 Sensory conflict theory assumes that the neurovestibular inputs that induce SMS are rearranged.) do not have a direct correlation to SMS symptom onset in space. Note -. Pre-flight adaptation testing (PAT) has shown a significant reduction in the severity of SMS. patient histories. but not all. the central nervous system has four inputs. ground-based testing and physiological research (questionnaires. Still.97 The atrophy can range from 10 to 20 percent on short missions to as much as 50 percent on longer missions. countermeasures have been developed. etc.91 Drug therapies. In three-dimensional space.88 The first countermeasure to SMS is knowledge and prediction. without mediation.Angular acceleration is measured by the three semicircular cannels of the inner ear.95 96 Muscle Atrophy Muscle atrophy and the excretion of nitrogen through the urinary system begin when the human body is exposed to microgravity.90 Head restraints have met with limited success.89 However. the change alters the stored (known) pattern of the four inputs and induces SMS. such as promethazine. When microgravity is introduced.94 Artificial gravity is still being research and has shown some adaptation enhancement during pre-flight and inflight testing.87 They are linear and angular acceleration and visual and kinesthetic inputs.92 93 Vestibular prostheses can be used to overcome proprioceptive inputs that cause SMS. 99 A quick reference that can be used is muscle diameter measurements. The bottom line is this: The key for space travellers is to perform their operational functions to the best of their abilities both cognitively and physically. Bone Loss Bone loss in microgravity is characterized by a 1-2 percent loss per month.103 With these changes.106 Initially.105 Imagine athletes complaining about sore muscles after a workout.101 Reduced muscular strength in various parts of the body has also been noted based on the muscle contractile response. This hindrance affects their primary function. in addition to fiber size reduction within the first six days of exposure.104 This regenerative ability is the function that allows the muscles to grow from the constant damage and healing that occurs. The Mir space station has produced test results in which metabolism has been reduced by 15% in microgravity environments. losses do not cease over the long term. the ability to withstand the stresses associated with the acceleration and deceleration of the launch and recovery phases of the mission. however. They compile and last for several months after the space traveller returns to gravity. however. this measurement also entails fluid transfer from the lower to the upper extremities and should only be used as an analog. it is postulated that the atrophy is caused by changes in muscle metabolism.107 16 . walking and standing. nitrogen scavenging also affects the regenerative abilities of muscles to heal themselves. and the stamina needed to endure them. this does not seem to be that detrimental.100 Unlike muscle atrophy common to earthbound cases of non-use (after surgery or healing from a broken bone with a cast).102 This strength loss manifests during extension more so than during flexion. Diet. Like the muscle atrophy. manifested similar results to the Mir station findings. the body weight increases due to an increase in sodium and water retention. primarily to counteract the calcium depletion that leads to bone loss and demineralization.112 Conversely. has 17 . including fluid loss. utilizing high-tech fabric and materials to cover the body and make even basic movements more taxing on the human body. focusing on hip loading.)109 110 Effects on the bone structure as well as the blood cell-forming marrow are great concerns because they can lead to a greater risk of fracture and difficulty in recovering from other forms of damage to the body. Bone loss is attributed to demineralization through calcium scavenging. the lower extremities and load-bearing bone structures suffer the largest amount of loss.111 Bone and muscle mass (more than 30 percent of the body) show an overall reduction of 5 percent in the first two weeks of travel.115 Other studies.108 The calcium must be excreted from the body through the kidneys and causes a greater chance of kidney stones (a potentially deadly side-effect. such as wounds.116 Note — Non-load bearing structures did maintain their density in the Mir studies.114 The results from the Mir and Skylab regiments of two hours per day of intense exercise only marginally slowed the predictable bone and muscle degradation. which are similar to power lifter singlets. Muscle and Bone Loss Countermeasures Exercise is the first countermeasure that is discussed regarding any type of muscle and bone loss. Methods involved in recent and past studies have been a combination of aerobic and anaerobic activities including “penguin” suits. in addition to supplemental calcium at a dosage of 1000mg per day. Nutritional and pharmacological countermeasures have also been prescribed to crew members.113 It is assumed that the contradiction of fluid loss and fluid retention is caused by the different densities of the fluids. 124 Microgravity affects the cardiovascular system in two broad paths: in-flight and post-flight responses. Monitoring is also deployed in order to measure the medical condition of the space travellers.118 Pharmacological countermeasures have been studied for space and osteoporosis patients. 18 . Cardiovascular System Damage The cardiovascular system is comprised of the heart. been shown to improve the balance of calcium levels for up to three months. In this case. and the fluid balance in the body. Lastly.121 Research continues. From aids research. with varying results. and kidneys. as well as human growth hormone (hGh). with varying results based on the lack of duration and the lack of a more effective means of producing artificial gravity in space. administering testosterone for men and estrogen for woman. lungs.122 The system is responsible for blood transportation to and from the heart. the removal of waste. are also standard practice for space flights. including prescreening for hypercalciuria.119 Other countermeasures.120 These measures are universal because of the host of stresses involved.117 Like on earth. with increasing dosage and long-term supplementation yielding diminishing returns. the regulation of temperature. Vitamin D (a problem due to the lack of sun light) and vitamin K are also supplemented because they have been shown to help maintain bone mass balance. artificial gravity (AG) has been used as a countermeasure.123 The blood is the mechanism for the supply of nutrients to cells. circulatory system. and many researchers believe that AG can be an effective countermeasure in the near future. 350mg has been found to be the best coupled dosage. calcium is synergistically coupled with magnesium. can be an option for bone loss and muscle wasting. blood pressure changes. also known as “Puffy face.126 The conditions manifest in flight and continue until after the travelers are returned to Earth or possibly Mars. such as increased heart rate. the intolerance is especially apparent immediately after landing.134 The other obvious physical appearance change is size loss in the lower extremities.129 Cardiac atrophy (a decrease in the size of the heart muscle) appears to develop during the space flight. with no data existing beyond nine months of flight.131 Research has suggested that cardiac atrophy and orthostatic hypertension may be significant problems during and after long-duration space flights to Mars. The fluid shift is more obvious during the early stages of the flight (6 – 10 hours). more blood is allowed to flow towards the upper portion of the body.125 The physical manifestations of orthostatic intolerance are diminished by exercise and physical activity.128 The Russian cosmonauts who spent over twelve months in space have little or no data associated to the cardiovascular system. Orthostatic intolerance is determined by symptoms experienced after standing.132 This is similar to the supine position induced during launch for proper acceleration tolerance.130 Such atrophy may have been a potential mechanism for the cardiac arrhythmias (irregular heart rhythms) identified in some crewmembers after long-duration exposure to microgravity aboard the Mir space station. which makes the heart work harder because of the added pressure and the required cardiac output. with the subject’s face being fuller in appearance. leading to diastolic dysfunction and orthostatic hypotension (a drop in blood pressure upon standing). and fainting. commonly referred to 19 . With the change in gravity.”133 The fluid shift also alters the thirst mechanism early on and may induce de-hydration.127 The recovery varies greatly with regard to pre-existing conditions and the duration of the flight. which measures the heart rate continuously for extended periods. and two Actiwatches.15 percent to 2 – 4 percent. with a plasma reduction of about 22%. which measures blood pressure with every heart beat. to monitor and record body movements. and anxiety disorders. depression.139 Examples of the monitoring devices that can be deployed in space include a portable Holter monitor. a Cardiopres. Note that the location of the mission on its operational timeline may bring about the onset of symptoms. one on an ankle and one on a wrist. total losses in the lower extremities are from 10 . Two of the common approaches would be prescreening for medical conditions and in-flight cardiovascular training.141 Each of these possible issues can be exacerbated by what researchers call “Third Quarter Phenomenon. as “chicken leg syndrome.”142 Many factors contribute to these psychosocial issues.136 Cardiovascular Countermeasures The countermeasures developed to combat the effects of microgravity on the cardiovascular system are similar to some of the basic countermeasures used against other challenges in the microgravity environment. For example. a crew member may be fine during the first part of the mission because the environment is new. They are interpersonal conflict. After the midpoint of a mission.”135 After several days in orbit. the same crew member may experience what researchers call the 20 .137 Low body negative pressure (LBNP) chambers and bungee cord suits (“penguin suits”) can be utilized to either increase the flow of fluid back towards the lower extremities in the case of the LBNP or to pull the body together and create a pressure shift in the case of the other device.138 Monitoring is also important in preventing cardiovascular stress and gathering data.140 Psychological Factors There are three key psychosocial issues associated with space travel. astronauts onboard Skylab went on strike for one day to rebel against ground control because of the workload.146 For example.148 Depression can be a result of isolation and the frustration of not being able to change an event.150 Depression could terminate the mission based on the health of the crew members and the overall effectiveness and safety of the team. “Third Quarter Phenomenon” because of the self-realization that an equal amount of arduous time is left until the completion of the mission. such as Antarctic research stations and nuclear submarines.149 Symptoms of depression can include lack of sleep. it will be very difficult to change course and evacuate crew members.147 The result of the Skylab strike and several examples of such conflict on Russian and other NASA missions was crew members having the ability to schedule as much of their own operational time as possible. the environment (like low light levels). person-to-control conflicts can arise between the crew members and ground control. as it would on Earth.143 This phenomenon has been seen in analogs. especially after the mid-point of the mission timeline. resulting in the possible termination of the mission. All crew members must be conscious of conflict resolution strategies so that the conflicts that arise do not interfere with mission goals. however. 21 . and in actual space missions conducted to date.145 During any mission. and a lack of motivation. however. eating habit changes. like the Mars trip. during the long mission to Mars. in 1973. In addition to person-to-person conflict. have a limited amount space for people to leave stressful situations and allow a conflict to have a cooling off period. or a combination of all the factors to various levels.144 Space missions consisting of six months or more. much of the data researchers use is anecdotal. unresolved conflicts can have a detrimental effect on group morale and function. the periods of symptoms come in waves. and mission mistakes156 American researchers do not fully subscribe to this notion of asthenia (neurasthenia in the US) as a full diagnosis of a disorder.152 Anxiety disorders manifest when worries or concerns about an event or circumstance concerning the mission increase. According to researchers.154 Note – Asthenia is a Russian term used to describe the following symptoms: weakness. however. and short-term memory reduction.157 The Russians treat this with pharmacological means prior to missions as a countermeasure. like the Mars 520 in Russia. irritability. First stage – irritability. reduced endurance.158 Countermeasures for these disorders range from select-in and select-out criteria for the initial crew formation to training. and increased apathy 2. and the environment aboard the spacecraft. conflict. shed light on the problems associated with long-term isolation. Second – fatigue and sleep disturbances 3. the concern regarding anxiety attacks precipitated by fatigue and other physiological factors is appropriate.153 Although rare on space missions because of screening and training. Simulations.155 1.159 22 . in which a crew was isolated from the outside with living conditions similar to the Mars mission.151 The results of the isolation tests make researchers believe that the trip to Mars is viable from an isolation standpoint. proper habitat. the hypothesis given is that as prolonged stress levels produce lower amines in the brain. lower attention span. Third – depression. fatigue in the evening. this results in susceptibility to depression and anxiety. fatigue. self-assessment. such as self-hypnosis and visualization.161 Mutual group support for the crew’s families is also a great way to combat these issues. Two specific examples would be upper body strength limitations and possible endurance issues associated with EVA.164 Therefore. and conflict resolution as part of the team building process.163 Note on gender differences – According to research. family counseling sessions should be scheduled to allow for specific planning for the duration of the mission and to prevent any unforeseen circumstance that can cause distress to crew members or families during the separation. with selections including men and woman and also single and married personnel. many feel that this is a non-issue.165 Women. the average differences between men and women are smaller than the differences between individual men or individual women. however.166 The key goal for mission planners is to take an objective approach to selection based on meritocracy.160 As the mission approaches. Included in team building. 23 . regarding which men have an advantage over women.162 Crew members should receive specific training for cultural differences. sports psychology techniques. however. the knowledge of specific gender differences known by planners is important. have an advantage over men in the case of kidney stone formation. Pre-flight Preparation Pre-flight preparation starts with functional training for individual team members and team building exercises to develop team cohesiveness. Survival training and parachute training deployed by Russian cosmonauts can also be employed to build confidence for the team traveling to Mars. should be employed. gender differences. as summarized in the body of the paper. The second reason for doubt is the ineffectiveness of certain types of countermeasures.170 This lack of data and exposure makes the Mars trip experimental. The information needs to be further divided into two parts: one for those complications for which there is no technological solution or countermeasure associated with the effects of traveling to Mars and the other for those complications for which current space travel has viable protection or countermeasures. Both of these challenges have short-term and long-term implications for astronauts. such as radiation shielding and a means of counteracting the physiological effects of microgravity for current missions inside the Earth’s protectionary mass. it may not be possible to overcome these challenges. such as sexual tension. with approximately 350 people going into space in the last four decades. The first reason for doubt is that there is not a substantial track record of long space missions. the mission planners can perform screening. which would be detrimental to the mother and the fetus. should be taken into consideration. conception during the mission. 24 . steps should be taken to coordinate timing prior to EVA.169 Summary and Recommendations There is vast amount of information to digest when determining the viability of a manned mission to Mars.167 Other mission factors such as sex or. should be avoided by means of professionalism and concentration on mission goals. Although there is no data showing that menstruation contributes to DCS. and a host of protectionary functions.168 Other factors. countermeasures. Although. Specific mission factors must also be taken under advisement. more importantly. The “Show Stoppers” The two primary challenges regarding a trip to Mars are the effects of radiation and the microgravity environment on the human body. It has a great deal of unknowns. 173 The research associated with launch planning to shorten the mission with alternative propulsion. NASA and Russia have not ventured past the protectionary boundaries of Earth since Apollo. and logistics. Krishen from the Johnson Space Center (JSC) points out that the minutia. vacuum. The Minutia In addition to the primary challenges of radiation and microgravity. habitat.171 Need for Further Research on New Experimental Fronts Here is a very small list of somewhat far-reaching research being performed by scientists and researchers that can offer alternatives to standardized mission beliefs for the trip to Mars: Mini-Magneto Spheres for active shields protecting the spacecraft and astronauts from radiation. However. power. researchers cannot forget about the other technology required for the trip. Minor challenges. moreover. plasma interaction. the technology needs to be tested in an environment outside the ISS. even though a great portion of it has been tested during previous missions. avionics. sleep patterns. provided that researchers invest the time and effort. such as an artificial gravity apparatus or giant water tanks for radiation shielding. Designs can always be improved or replaced with new designs. such as safer propulsion. have been at least intermittently solved by current technology and a proven track record in space. such as extreme temperatures. Technology has improved drastically since Neil Armstrong’s walk on the surface of the moon. cannot be overlooked for the trip to Mars. micrometeoroids. EVA. Dr. including cosmic radiation. temperature control. navigation.172 Nuclear propulsion research to propel a larger spacecraft carrying larger alternative countermeasures for microgravity. as well as non-Hohmann transfer launches and 25 . and others. Only when all the milestones are reached should the mission to Mars be green-lit by the Office of the President and NASA.) Researchers and mission planners must be conscious of the alternative research being conducted and not be stymied by traditional beliefs. and all alternative must be considered. as well as a push for alternative (non-mainstream) research. Final Recommendation The final recommendation is to invest the reported 30 years and $400 billion cost into a workable plan with milestones. This research must be performed in parallel with that regarding the minutia mentioned by Dr. If and when these research initiatives provide viable countermeasures.176 The milestones should be based on the development of countermeasures for radiation and the effects of microgravity on the astronauts. Krishen. an unmanned mission should be conducted with either automated animal habitats or other analogs for humans in order to measure the effectiveness of the research and the trip. burns. 26 . 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