The Challenges Astronauts Will Face During the Mission to Mars

challenges astronauts will face during mission to Mars

The human mission to Mars is still some time away. A report from the Science & Technology Policy Institute concluded that the earliest NASA would be able to send astronauts to Mars would be the late 2030s, although Elon Musk has remarked that SpaceX’s first Starship journey to Mars could go ahead in the next four years, as part of plans to set up a permanent and self-sustaining human presence on the Red Planet. Musk, however, is well-known for creating ambitious timelines for his pioneering inter-planetary trip.

The reason it may not be until the late 2030s that such a venture will materialise is that the project is a colossal logistical and technological feat like no other. All manner of training, precautions, and measures need to be in place before such a trip is deemed safe and feasible. On any mission to Mars, there are myriad health and practical challenges that astronauts will have to face, and I’d like to draw attention to some of these, as they really bring into focus just how much of an achievement a mission to Mars will be, and I personally find them fascinating, as they call into question the limits of human psychology and the sustainability of long-duration space travel. Astronauts will be entering completely new terrain when embarking on a journey of this magnitude.

Health Challenges During the Mission to Mars

It will take between 6 to 9 months to get to Mars. The time it takes depends on the speed of the launch, the alignment of Earth and Mars, and how much fuel is used. Regardless of how long it takes, it’s a very, very long journey. And one of the challenges for astronauts is staying healthy. In fact, there are many obstacles that get in the way of maintaining health during long space missions.

In one respect, it is not nutritional deficiencies that astronauts have to worry about during the long-haul flight to Mars, but nutritional excess. In an analysis of 23 astronauts’ blood and urine samples, researchers found that extended spaceflight resulted in too much iron. This is because during spaceflight your blood volume contracts, which increases iron storage.

In the analysis, authors discovered that all of this extra iron may be the culprit for the bone loss that astronauts experience. The study showed that increased storage of iron correlated with increased bone loss in astronauts on missions ranging from two to eight months. Of course, if a Mars mission takes up to nine months, then there is a higher risk of bone loss causing issues.

Astronauts lose bone density at an average rate of 1-2% a month. This may seem minor at first. But consider the rate at which an elderly person loses bone – 1-2% a year. Decreased bone density means an increased risk of bone fracture. Trying to colonise Mars with broken bones will not be an easy task.

NASA astronaut Scott Kelly says that “the effect of diet on bone is likely greater the longer you’re up there”. If we’re going to get to Mars safely, then special attention must be paid to nutrition.

Long-duration missions need the right amount of nutritional requirements for protection against the effects of microgravity. Weightlessness affects almost every system in the body, including those of the muscles, heart and blood vessels, and nerves.

The mental health effects of space missions, such as those caused by an increased sense of isolation, could also be addressed by nutrition. For example, omega-3 fatty acids and vitamin D play an important role in maintaining good mental health. Poor mental health during space flights is an issue because it can result in less productive missions and decreased crew morale. In addition, environmental factors (including radiation and spacecraft and spacesuit atmospheres) can change the nutritional requirements of space flight.

Little research has been done on differences in fuel components (i.e. protein, carbohydrate and fat) during space flight, or other factors (e.g. vitamins) relating to energy utilisation. But it is worth highlighting what evidence has been gathered so far.

Adequate energy intake is considered to be the single most important aspect of astronaut nutrition. This is not only because energy is more important than nutritional factors, in and of itself, but also because if enough food is consumed to meet energy needs, then generally other nutrients will be consumed in reasonable amounts.

High-energy foods include complex carbohydrates, spinach, sweet potatoes, fruit, nuts, soybeans and pumpkin seeds. Also, B vitamins play a crucial role in the conversion of food into energy. So ensuring an adequate intake of B vitamins is important.

One study found that heavy resistance exercise plus adequate intake of vitamin D reduced the loss of bone mineral density on long-duration International Space Station (ISS) missions. Given the serious risks posed by bone loss, eating foods high in vitamin D or taking a vitamin D supplement may be advisable.

As SpaceX gets busy with its plans to colonise Mars, all of these considerations (and more) will need to be taken into account. If we can’t overcome the health challenges posed by long-duration flights and existence on another planet, then the Mars colony will not be sustainable.

Injuries and Illnesses in Space

Journeying to Mars will involve some unique health risks that astronauts may have to confront during the mission to Mars. After all, the round-trip to Mars will take around three years (with one year spent on the surface of Mars itself) – and this is ample time for health complications to occur. 

Intensive care expert Matthieu Komorowski has warned that astronauts will need extensive training in order to treat life-threatening illnesses and injuries during the trip to Mars. Crew members do undergo some medical training, but it is very basic and covers only a fraction of the medical expertise that a qualified medical doctor has. Komorowski said:

During these long duration flights, the estimated risk of severe medical and surgical events, as well as the risk of loss of crew life are significant.

The exposure to the space environment itself disturbs most physiological systems and can precipitate the onset of space-specific illnesses, such as cardiovascular deconditioning, acute radiation syndrome, hypobaric decompression sickness and osteoporotic fractures.

Thus, there are many kinds of illnesses and injuries that could befall an astronaut. Jochen Hinkelbein, from the Department of Anaesthesiology and Intensive Care Medicine at the University Hospital of Cologne, says “there is also a substantial risk for a cardiac arrest in space requiring CPR.” But the microgravity environment of space makes CPR kind of difficult since it requires a person to use their body weight. So medical techniques need to be developed which will work effectively in a microgravity context.

Furthermore, a study last year found that astronauts who had travelled into deep space have a “significantly higher” chance (43%) of experiencing cardiovascular problems compared to astronauts who hadn’t gone into deep space. This is due to the effects of deep-space radiation.

Astronauts are of course screened for good health and are continually monitored throughout their training in order to identify any health risks. But long-term missions increase the risks significantly. This means that all factors that can contribute to cardiovascular disease (CVD) – which includes all diseases relating to the heart and cardiovascular system – should be controlled for. This is where nutrition plays a crucial role, as some foods can increase the risk of CVD, while others can decrease that risk. For example, processed meat (which is part of an astronaut’s diet) heightens the risk of developing coronary heart disease (CHD). On the other hand, there are many foods that protect heart health, so perhaps an astronaut’s diet should include more of these foods – or, if some are already on the menu, then they could be eaten in larger quantities or more often.

A study published in Scientific Reports predicts a significant increase in cancer rates among astronauts destined for the mission to Mars or any other long-term mission. This is because the Earth’s magnetic field provides protection against galactic cosmic ray (GCR) exposure, rays which can increase the risk of not only cancer, but also damage to the central nervous system, cataracts, circulatory diseases, and acute radiation syndromes. And the longer that one is exposed to GCRs, the higher the health risks. Indeed, study author Francis Cucinotta says that the mission to Mars could double the risk of developing cancer.

As more research is being done on the health risks of long-term missions, we are learning more about how taxing, arduous, risky and potentially life-threatening it is for a human – who has evolved specifically on Earth – to travel in deep space for years at a time. Ensuring a successful and safe mission to Mars is far more important than landing on Mars as soon as possible. All possible risks must be studied, carefully assessed and accounted for in the planning and preparations. 

Staying Fit in Space 

One of the obstacles involved in the mission to Mars is ensuring that astronauts stay fit in space. Before British astronaut Tim Peake went aboard the International Space Station (ISS) for 180 days, NASA said his muscular strength could decrease by between 11 to 17%, muscular endurance by 10%, and bone density by 2 to 7%. So astronauts have to keep fit, not just for the reasons that apply to us on planet Earth, but also to offset the effects of microgravity on the body. 

NASA has developed the Advanced Resistive Exercise Device (ARED) to mitigate the atrophy of bone and muscle in the microgravity environment. NASA points out that the muscle mass that is lost could be difficult or even impossible to regain back on Earth. ARED’s main goal, therefore, is to help astronauts maintain muscle strength and mass in astronauts during long-duration spaceflight. Astronauts will need to exercise for about two hours every day in order to achieve this.

Exercise machines on Earth involve gravity, like lifting weights or running, to build strength and fitness. But in space you’re weightless. So the ARED helps astronauts to stay fit in space by using a piston and flywheel system to simulate free-weight exercises, such as squats, deadlifts, and calf raises. The results that you get from using the ARED are similar to those seen with free-weight training. This machine can also help improve endurance, which will make a difference when it comes to physically taxing tasks, such as spacewalks.

NASA has also released video footage on their Tumblr page of the Miniature Exercise Device (MED-2) in action. It is a compact, all-in-one exercise device, and it takes up way less room than the ARED. Deep-space vehicles (like the Orion Spacecraft) aren’t as spacious as the ISS, so the less space that an exercise device takes up the better.

With the MED-2 astronauts are able to do both aerobic and resistive exercises. Weighing in at 65 pounds, it is extremely light. It is also a flexible machine, offering 5-350 pounds of resistance, which caters to the different strength abilities of the astronauts. Also essential to the Mars mission is the efficient use of resources. MED-2 charges during aerobic exercises, and this power is then used for the resistive exercises.

However, experts still don’t know how much bone and muscle loss would result after a three-year round trip to Mars. The loss could be so significant that exercise devices and diet plans will still need to be improved greatly in order to account for it.

Since astronauts can’t exercise all the time, there are other ways that they can stay fit in space. Dr Graham Mann, from Murdoch University’s School of Engineering and Information Technology, says: “By arranging uniforms with special elastic straps connecting, say, your legs with your upper torso, it is possible to apply a constant artificial tension across the body.”

This tension will help to continue muscle toning as the crew carry out their daily work. However, even if an evidence-based exercise routine can protect astronauts against the dangers of bone and muscle atrophy, they will still have to commit to doing these exercises every day. It’s hard enough to motivate yourself on Earth to go to the gym, even once a week, to exercise for an hour. It will definitely take a different kind of discipline to exercise every day for two hours.

There are also some psychological challenges that could get in the way of crew members keeping fit in space. For example, it has been suggested that the isolation, loneliness, limited social contact, intense homesickness, and conflicts experienced during the mission to Mars may result in depression among some astronauts. While mental health screening and a highly vetted selection process may mitigate this risk, it doesn’t eliminate it.

Anyone who suffers from depression knows that one of its most frustrating symptoms is the lack of motivation. You know that exercise will help to relieve the other symptoms, such as low mood, but it’s hard to find the energy to actually get yourself to the gym and exercise. This would be risky, since if an astronaut refuses to exercise, what can the other crew members do? Force them to exercise? Not likely. So then what you have on your hands is one crew member with not only psychological problems, but now also physical issues, as his fitness starts to deteriorate due to lack of exercise. It would therefore become much more difficult for them to carry out their duties. This is a potential problem that experts need to carefully consider.

The Psychological Effects of Space Travel

There are a number of behavioural issues that could affect crew members during the three-year round-trip to Mars. The psychological effects of space travel are being examined before the mission to Mars is launched. 

In one study, the relationships between crew members, and between crew members and mission control personnel, were investigated. Researchers found that crew members would displace their tension and negative emotions onto mission control personnel.

A separate study stressed that crew members showed decreases in the scope and content of their communications and a filtering of what they said to mission control personnel. Some astronauts interacted less with some mission control personnel than others, perceiving them as opponents. Indeed, authors of the study found some astronauts became more egocentric in isolation, which could prove to be problematic during the mission to Mars.

However, some of the psychosocial effects of isolation were quite positive. For example, researchers found that crew members could function as a cohesive unit because of the time they spent together. On the other hand, outliers negatively affected group cohesion.

A study titled Cross-cultural training requirements for long-duration space missions (2007) noted other difficulties by surveying astronauts and mission control personnel. These include coordination difficulties between the different space organisations involved with the missions, as well as communication misunderstandings and differences in work management styles.

And other fascinating research asked cosmonauts what psychological and interpersonal problems they thought might occur during a Mars expedition. Researchers highlighted several answers: isolation and monotony, distance-related communication delays with Earth, leadership issues, and cultural misunderstandings within international crews.

One of the most challenging psychological effects of space travel is the feeling of being isolated. While astronauts have other crew members to interact with and talk to, this is no substitute for lifelong friends and family, or all of the other acquaintances and new faces that we see on a daily basis. But it’s not just isolation from loved ones back home that can cause issues. Being separated from planet Earth itself can be difficult. In her book Packing for Mars: The Curious Science of Life in the Void, author Mary Roach writes:

People can’t anticipate how much they’ll miss the natural world until they are deprived of it. I have read about submarine crewmen who haunt the sonar room, listening to whale songs and colonies of snapping shrimp. Submarine captains dispense “periscope liberty”—a chance for crewmembers to gaze at clouds and birds and coastlines and remind themselves that the natural world still exists. I once met a man who told me that after landing in Christchurch after a winter at the South Pole research station, he and his companions spent a couple days just wandering around staring in awe at flowers and trees. At one point, one of them spotted a woman pushing a stroller. “A baby!” he shouted, and they all rushed across the street to see. The woman turned the stroller and ran.

Freudian psychiatrists also speculated decades ago that separation from ‘mother Earth’ could lead to pathological ‘separation anxiety’. They said that this anxiety could lead to a temptation to escape through suicide or oblivion, even accompanied by an urge to destroy the space ship and all of the other crew members. However, NASA has guidelines on how to handle a situation where a crew member becomes dangerously agitated during space travel. It involves duct tape, bungee cords, and tranquilisers.

Earth is the only home we’ve ever known and to be away from it for so long, and to be so far removed from everything associated with life there – well, this could indeed create an intense feeling of homesickness. After all, feeling homesick on Earth can easily be fixed, but it’s completely different when you’re on a three-year expedition to another planet. It could create a very uncomfortable sensation of being trapped.

The six men who endured a 520-day simulation of a Mars-bound mission reported feeling bored and lacking motivation. Psychiatrist Mathias Basner, from the University of Pennsylvania School of Medicine, said: “Four of them showed at least one issue that could have exploded or led to a severe adverse effect during a Mars mission.”

During another simulation, two of the crew members never spoke to each other except when it came to mission-critical exchanges. Their near-silent treatment lasted 18 months. Many issues could arise if you had crew members not speaking to each other during a three-year-long trip.

Perhaps the psychological effects of space travel can be mitigated through the selection process since only a small subset of astronauts will be willing to be away from friends and family for so long. Whilst those on the Mars500 mission reported negative psychological effects, this doesn’t mean that all crew members would succumb to these effects. A very particular kind of astronaut may be able to thrive during long-duration spaceflight. But nothing’s for certain. It could be that the very nature of human psychology itself will make the mission to Mars an inherent challenge. More simulated missions will be necessary to get to grips with these complex issues.

Sex in Space

Although it doesn’t look like astronauts have been hooking up in space, it’s probably going to happen eventually. Professor Lawrence Palinkas from UCLA said:

Certainly at polar research stations, there’s sexual relations, sexual contact, between men and women. On a three-year mission to Mars, that’s a possibility as well, although NASA in the past has tried to downplay the need for and the implications of sexual needs on a mission that long.

But if sexual intimacy is a basic human need, then NASA shouldn’t be downplaying it. If they are working on tackling the problem of menu fatigue by developing suitable menus and the possibility of cooking in space, then the problem of love/sex deprivation should be addressed as well. It might be a bit more awkward to examine the issue, but in order to ensure that the mission to Mars is going to be successful, then we have to be realistic about the challenges involved.

Going without sex for three years can easily lead to sexual frustration. Astronauts, like all people, will no doubt have sexual thoughts, feelings, and desires during this time.

Since the 80s, space missions have been co-ed, routinely including one or two women. Professor Jason Kring, of the Embry-Riddle Aeronautical University in Florida, said: “[For] a true long-duration mission if we go to Mars or back to the moon, politically, I don’t think you’re going to see an all male or all ‘American’ crew.” He added that, politics aside, “research would suggest that a mixed crew of men and women would probably be best.”

Other than deciding to hook up with a crew member, there is also the challenge of actually having sex in a microgravity environment. In her book Sex in Space, science journalist Laura Woodmansee writes about several positions that could work.

This doesn’t mean that ‘spacesturbation’ isn’t a thing, but perhaps the sexual needs of astronauts aren’t getting enough attention. Keeping astronauts happy in space makes a smooth and successful mission all the more likely; so since intimacy and sex are both closely linked to well-being, NASA may have to take these matters into account.

Meeting the Human Need for Love and Intimacy

In 1943, psychologist Abraham Maslow published a paper titled A Theory of Human Motivation in which he developed a ‘hierarchy of needs’. This hierarchy is often presented as a pyramid, with more basic needs at the bottom. Maslow’s hierarchy of needs has been criticised, but nonetheless, it can still offer a useful perspective on human motivation. The third category from the bottom is love/belonging. Indeed, other psychologists maintain that love and belonging are fundamental human needs.

The need for love and belonging can be expressed in many ways. One of these is sexual intimacy. Other ways include being nurtured, in the form of contact comfort – the innate pleasure derived from close physical contact. Humans seem to have a need for some kind of physical touch; without it, we fall prey to what is known as touch starvation, which entails all kinds of adverse effects on well-being.

Our need for love means that we seek out healthy relationships in order to feel fulfilled. But of course, love isn’t a one-way street. We also have a desire to love and nurture others. Professor Michael Norton delivered a fascinating TED talk on this deep-seated and universal desire to love others. We don’t always recognise it or express it, because of cultural influences, but it’s there.

We can see past the cultural message that happiness lies only in being the recipient of love, rather than the giver. And we can take steps to become a more loving sibling, friend, or partner. But for an astronaut, it’s slightly different. The mission to Mars could be three years in duration. And for all this time they will be without their family, friends, and partner (or any potential partners). Being in space for so long will really highlight how deep-seated this need to love and be loved is. Because going without it for so long will start to affect the astronauts’ well-being.

Sexual intimacy is just one aspect of love. While crew members might become sexual partners, this doesn’t necessarily mean they will love each other. The human need to be loved and to love could be met by the deep bonds of friendship that form among the crew members. Also, talking to loved ones back home is important. Astronaut Tim Peake said that “even astronauts need hugs”. So perhaps crew members will have to become a bit more intimate with each other.

Experiencing Menu Fatigue 

‘Menu fatigue’, simply put, is getting bored with what you’re eating, because you’re eating the same food too often. Soldiers in the army have complained about monotonous meals. But it’s also a problem for astronauts. Eating ‘space food’ every day for months, or even years, is bound to get boring.

Astronauts today eat a much better variety of space food than what astronauts ate during the Gemini and Apollo missions of the mid-60s. These earlier astronauts ate food that was all dehydrated, freeze-dried, and bite-sized.

Today, astronauts can order from a menu, with far more options than you’d find in a restaurant. There are more than 200 food and drink choices. These are developed at the Johnson Space Center. Some food is dehydrated like in the 60s, in order to save on space and weight. Fruit, fish, and meat are thermostabilised or irradiated to kill micro-organisms and enzymes. Nuts and baked goods are fine as they are. On holidays, special items can be requested. And ‘psychological support kits’ can also be provided by family and friends, containing some requested treats. For ISS crewmembers, the menu repeats every 8 days.

Now you may be thinking that this sounds pretty manageable. True, having more options than a restaurant is still fewer options than choosing from a range of restaurants. But isn’t having a somewhat diverse range of nutritious food enough? Shouldn’t we be focusing on more important issues, such as the logistics of getting to Mars in the first place? Well, it turns out that menu fatigue is still a big issue for astronauts today.

An assortment of foods isn’t in itself enough to ward off food boredom. Mary Roach, author of Packing for Mars: The Curious Science of Life in the Void says that there’s a general problem with space food. It doesn’t taste quite like what you’d have back home; it’s “either blander or there’s a weird flavour”. Roach highlights: “It’s highly processed, pasteurized and tweaked a million ways to deal with the packaging and the safety and the shelf life.”

TED Senior Fellow Angelo Vermeulen led a four-month study, simulating cooking and eating on Mars. He emphasises just how important food is to astronauts. He said, “food is absolutely crucial to the psychology of your crew, and you need to handle that carefully.” If one aspect of space travel starts getting astronauts down – such as food – then this can affect other areas, such as team morale. But further improvements can be made to combat menu fatigue. Food can be more than just a way to provide fuel for astronauts. 

Astronaut Tim Peake was able to eat food from a menu created by chef Heston Blumenthal. It included a bacon sandwich, Thai red curry with rice, baby corn, bamboo shoots and chilli, sausage and mash with onion gravy, beef stew with truffles, smoky Alaskan salmon, and key lime pie. Now compare this to the Apollo-era menu: bacon squares, dry-bite coconut cubes, and rehydratable chocolate pudding. It’s clearly a massive improvement. Other award-winning chefs are also getting involved since NASA realises how valuable it is to have tasty, comforting, and interesting food on board during space missions.

There’s still work to be done. Since the round-trip mission to Mars can take up to three years, and so an eight-day rotation of food could get boring very quickly. But there are other ways to get around this problem. Vermeulen says “one of the solutions is to allow the crew to cook”. He adds: “Cooking empowers you over your food. You can make endless variations, and there’s a bonus: it improves social cohesion. You talk about food, you share food. It’s a basic human thing.”

Hydroponic growth labs could allow astronauts to grow vegetables, potatoes, soybeans, wheat, rice, and beans. But the cooking aspect does present some challenges. It requires water and energy, which are very precious resources in space. It also demands that astronauts dedicate some spare time for cooking, which they don’t always have. Also, there’s the practical challenge of cooking in a microgravity environment. So far it looks like fries are off the menu. But it’s important to overcome these challenges. Vermeulen emphasises the benefits of cooking that he noticed from his study:

During our mission we always cooked with two people, and this had an interesting psychological benefit. When people are in the kitchen cooking, they are also talking. It’s a good way to keep the communication lines open. It’s also a really good outlet for creativity — something you really crave for when you’re locked up in a small space. And then when the food is served, you’re actually proud of what you made and you’re serving it to your colleagues. It generates more social cohesion.

Efforts to tackle menu fatigue continue. Perhaps the bigger challenge is ensuring that once astronauts arrive on Mars and set up a colony that they can cook original meals, as well as different cuisines. There will also need a variety of foods to suit different tastes. Also, as humans, we all want our comfort food. Without that, the trip to Mars, and life on the Red Planet, will become a drag.

Based on all of these considerations, we can see that astronauts on the mission to Mars will be putting their well-being at much more risk than they have in previous, shorter space missions. While utmost importance, care, and attention will be placed on protecting the health and sanity of these astronauts, any one of these astronauts must be prepared to deal with potential challenges, hardships, and setbacks. The bravery and commitment really cannot be understated; it takes a rare kind of person to be capable of space exploration, and an even rarer subset of those people suited for long-duration space travel. When (or if) the Mars mission does take place, it will be a human experiment like no other and only time will tell how it will pan out for the astronauts involved.


  1. Anonymous
    November 30, 2020 / 12:58 am

    It could be that the very nature of human psychology itself will make the mission to Mars an inherent challenge.

    • Sam Woolfe
      November 30, 2020 / 9:28 am

      I think that’s true, or at least, we’ll see how much human psychology will be challenged by a mission of this scale.

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