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In the movie The Martian, Matt Damon’s character faces an endless battle for survival after being stranded on Mars. However, in reality, the journey to Mars and the adaptation to life on the planet would pose significant hurdles before any astronaut was left behind.
In addition to the dangers of radiation, extended time in space, and the strain on mental health, there are several other critical challenges that astronauts would encounter during real Mars missions.
10. The Longer Duration of a Martian Day
A day on Mars lasts 40 minutes longer than a day on Earth. While it might seem like a gift to gain an extra 40 minutes each day, the human circadian rhythm is naturally attuned to 24 hours. This additional time would quickly lead to perpetual jet lag for astronauts, leaving them in a constant state of fatigue.
NASA experienced this challenge firsthand when mission controllers had to adjust to ‘Mars time’ in order to sync with the first Mars rovers' schedules. The entire control team for the Sojourner rover operated on the same time as the rover, but after a month, the controllers had had enough.
For subsequent Mars rover missions, controllers managed to stay on Mars time for three months, but were utterly drained by the end. It seems humans can only tolerate Mars time for limited stretches. For astronauts stationed on Mars for months, there would be no escape from the Martian schedule.
Earlier research suggested that humans have a natural 25-hour circadian rhythm, but newer studies disproved this theory. None of the participants could adjust their rhythms to match Mars time in the follow-up studies.
9. The Reduced Gravity on Mars’ Surface
While scientists can replicate a Mars journey by sending astronauts to the International Space Station for long durations, the effects of prolonged exposure to Mars' gravity, which is just 38 percent of Earth's surface gravity, remain unknown.
Will the reduced gravity on Mars help humans maintain essential muscle and bone density? If not, can exercise make up for it? With any potential Mars mission requiring astronauts to endure months in Martian gravity, this question is of utmost importance.
Two studies on mice, conducted using imperfect simulators, suggest that bone and muscle loss in Martian gravity might be as severe as in zero gravity. One study revealed that even in an environment with 70 percent of Earth's gravity, muscle and bone loss couldn't be prevented.
In the second study, researchers observed at least 20 percent bone loss in mice exposed to reduced gravity. However, it's important to note that these are merely simulations. Until astronauts actually set foot on Mars, we won’t know precisely how their bodies will adjust to the lower gravity.
8. Treacherous Martian Terrain
As Neil Armstrong encountered when he descended to the Moon's surface, his landing site was riddled with enormous boulders, which threatened the safety of his lunar lander. Astronauts landing on Mars could face a similar challenge, with only a limited time above the surface to spot and avoid hazards like large rocks or sand dunes.
Large boulders or steep slopes could cause a Martian lander with landing legs to tip over upon impact. Even substantial surface features may be hard to detect from orbit, which means mission planners might overlook them entirely.
Small depressions or hills could trick sensors into prematurely releasing the lander from its parachutes or confuse automated systems regarding the landing speed. The likelihood of a lander failing due to terrain complications is surprisingly high, with one study estimating the risk at up to 20 percent.
7. The Diameter of the Payload Fairing
When it comes to designing a manned Mars lander, one recurring technical issue is the diameter of the payload fairing used for the rocket launch. Despite considering a large 8.4-meter (27.6 ft) fairing, NASA has found it challenging to integrate the payload fairing into the design of the manned Mars lander.
The rigid heat shield required to safeguard a heavy payload is simply too large to fit within the payload fairing. As a result, NASA is exploring the use of an inflatable heat shield technology, which is still in the experimental phase.
Using current Mars mission designs, NASA’s smallest lander would be exceedingly cramped within the 8.4-meter fairing. Any of NASA’s larger landers would be unable to fit in the fairing.
Even with the smallest lander, NASA would be forced to make awkward redesigns, including flipping the Mars rover for the astronauts upside down and reconfiguring the fuel tanks. Increasing the size of the fairing is not an option, as it would destabilize the rocket.
6. Supersonic Retropropulsion
Supersonic retropropulsion could be one technique for slowing a Mars lander during its final descent to the surface. This method involves firing rockets against the direction of travel while the spacecraft is still moving faster than the speed of sound.
In Mars' thin atmosphere, supersonic retropropulsion becomes essential. However, firing rockets at supersonic speeds could generate shock waves that may damage the Mars lander. NASA has limited experience with this technique, making its success even more uncertain.
There are three primary concerns with this approach. First, the interaction between the airstream and the rocket exhaust could shake the lander apart. Second, the heat produced by the rocket exhaust may dangerously heat the Mars lander. Third, it may prove difficult to maintain the lander's stability during the retro-rocket firing.
Although small-scale tests in wind tunnels have been performed, a comprehensive series of larger tests using actual hardware is required. This would be a costly and long-term endeavor.
However, NASA may have an alternative route to studying supersonic retropropulsion. It recently reviewed a test conducted by SpaceX involving the return of its first stage to the ground, which provided valuable data.
5. Static Electricity
You know those little shocks you feel when you touch a doorknob or any other metal object? It's usually just a nuisance here on Earth. But on Mars, static electricity could pose serious threats to our astronauts.
On Earth, static discharges are mainly triggered by the insulating nature of rubber shoes. On Mars, the Martian soil itself would act as the insulator. By simply walking around on Mars, an astronaut could build up enough static electricity to damage sensitive electronics if they tried to open airlocks or touch the spacecraft's exterior.
Martian soil is incredibly fine and dry, making it an excellent insulating material. It’s up to 50 times finer than dust on Earth. As astronauts move around, the soil will stick to their suits. When the Martian wind blows it off, the astronaut would build up an increasing static charge.
The Mars rovers use ultrafine needles to discharge this built-up electricity. However, a manned mission to Mars would require specially designed insulating spacesuits to safeguard both the astronauts and their equipment.
4. Launch Vehicle Availability
The Space Launch System (SLS) is currently the largest rocket under development, expected to be the key launch vehicle to carry out a manned mission to Mars, piece by piece.
According to NASA's present plans, at least a dozen SLS rockets will be necessary for a single manned Mars mission. However, the current ground infrastructure supporting the SLS has been reduced to its bare essentials: a facility for rocket assembly, a massive crawler for transporting the rocket to the launchpad, and the launchpad itself.
If any of these components fail, it could create major complications for the availability of the launch vehicle. This potential bottleneck could lead to serious challenges for a manned Mars mission.
For instance, any delays in the assembly or inspection of the enormous SLS rocket could disrupt the planned launch timeline. Even something as routine as weather conditions or small technical issues could have a major impact.
Moreover, to assemble a Mars spacecraft in orbit, the rocket must launch during a very specific timeframe, known as the 'launch window.' Opportunities for Mars-bound missions to exit Earth's orbit are limited.
Using historical data on space shuttle launches, scientists have developed launch models that reveal NASA’s uncertainty in ensuring the SLS rocket will launch within these narrow windows, which could put Mars mission plans at risk.
3. Romances And Breakups
During long journeys in confined spaces, romantic relationships between astronauts become a real possibility. At the core of this, humans have a fundamental need for physical connection and intimacy. While this may seem sweet and romantic, it can also lead to complications.
In 2008, a group of volunteers was confined to a small space for an extended period to simulate a Mars mission. Tensions escalated when one of the astronauts grew upset that his astronaut girlfriend was spending more time with another astronaut and refusing his sexual advances.
Exhausted and under stress, the first astronaut lost control and ended up breaking the third astronaut's jaw. Had this been an actual Mars mission, such an outburst could have severely jeopardized the entire mission.
Sadly, NASA has yet to address these scenarios. A recent report from the National Academy of Sciences noted that NASA has not examined the potential impact of romantic relationships on Mars missions or researched which personality types would be best suited to live together in close quarters for prolonged periods.
2. Long-Term Storage Of Rocket Fuel
Rocket fuel is essential for a Mars mission, powering the spacecraft to reach and return from the Red Planet. The most efficient fuels currently in use are liquid hydrogen and liquid oxygen, both of which are cryogenic propellants.
These fuels need to be kept at extremely low temperatures for storage. However, despite careful preparation, hydrogen escapes from the tanks at a rate of 3–4 percent per month. If astronauts on Mars discover that they don’t have enough fuel for the return trip, it would be a catastrophic failure.
Astronauts may need to store the cryogenic propellants for several years while on Mars to prevent them from boiling off. Manufacturing additional fuel on the planet could be a solution, but maintaining the fuel at low temperatures would require advanced insulation and electric coolers. Prior to sending astronauts on Mars missions, flights will be necessary to test long-term storage technologies for the fuel.
1. Toxic Martian Soil
In 2008, NASA’s Phoenix probe uncovered a troubling finding on Mars: It discovered perchlorate salts on the Martian surface. These toxic compounds, while used industrially, pose a significant health risk as they can disrupt the thyroid gland even in minute quantities.
On Mars, perchlorates are present in the soil, making up at least 0.5 percent of it. This amount is toxic for humans. As astronauts move about and inadvertently bring soil into their habitats, contamination with perchlorates will be nearly impossible to avoid.
Drawing from decontamination techniques used in hazardous mining environments on Earth, technology could be employed to reduce the risks. However, astronauts may still experience serious health issues, particularly with the disruption of their thyroid glands.
Perchlorates have been associated with several blood disorders. Yet, the effects of these toxic substances on the human body remain largely unknown, as there has been little research done, leaving the long-term consequences uncertain.
To combat the ongoing health effects of perchlorate exposure, astronauts may need to rely on artificial hormones to maintain their metabolic processes during their time on Mars.
