Science & Technology

Will Humans Land on Mars? Learn About the History of Mars Exploration and 7 Key Challenges of Sending Humans to Mars

Written by MasterClass

Sep 9, 2019 • 7 min read

Mars exploration has long been the subject of human fascination. While missions to Mars are frequently the subject of science fiction books and movies, the reality may not be that far behind. Recent advances in space technology and the rapid commercialization of the space market may soon make a human mission to Mars possible. What’s more, if you look at the 300,000 year history of human exploration, it is evident that the need to explore is fundamental to our nature. Framed in this way, a mission to Mars isn’t really a question of if—it’s more a question of when.

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Why Should Humans Travel to Mars?

One of the greatest impacts of a mission to Mars would be finding life or evidence of extinct life, no matter how simple that life may be. It would not only answer the question of whether we are alone in the cosmos—but would also indicate that there is potential for life everywhere in the universe.

What Is the History of Mars Exploration?

Many spacecraft that have landed on the surface of Mars, including the Viking 1, Viking 2, and the Mars Pathfinder. Spacecrafts such as the Mariner 4, Mariner 9, Mars Express, 2001 Mars Odyssey, Mars Global Surveyor, and Mars Reconnaissance Orbiter have conducted survey work to map the surface of Mars. Mars Exploration Rovers from both NASA and the European Space Agency (ESA) explored the surface of Mars, sending valuable data and images back to Earth.

In 2010, U.S. President Barack Obama announced at the Kennedy Space Center in Texas a proposal aiming for a manned Mars mission by the 2030’s. NASA plans to launch the Mars 2020 rover mission, which will send an unmanned Mars lander to the red planet to explore the signs of life, both past and present.

NASA is also testing spacecraft designed to transport humans to Mars for the first time.

7 Key Challenges of Getting to Mars

The technical and engineering challenge to get to Mars is daunting. Earth and Mars have different orbits around the sun, which means the distance between the two planets is constantly changing. Even with an optimal launch window, it’s still a long voyage into the unknown with an unproven ship, hauling everything you need, with no way to resupply critical items. And that’s just the beginning. Other challenges include:

  1. Building the right spacecraft. Getting to the moon is a three-day trip, so a utilitarian spacecraft like the Apollo will suffice. The first Mars mission requires a much longer journey, so the spacecraft would need to have more living space, more room for backup systems, equipment for space walks, a reliable propulsion system, and—perhaps most importantly—recreation facilities to keep the astronauts engaged, productive, and sane during space travel.
  2. Air and water recycling capabilities. Much of what the life support system does on the International Space Station (ISS) mimics what happens naturally on Earth. Processors purify the astronauts’ air, filtering trace gases and removing their exhaled carbon dioxide. Where possible, the oxygen is extracted and released back into the cabin, but the small losses are supplemented with stored oxygen. Water is similarly recycled from urine and dehumidifiers, typically with about 90% efficiency. That’s better than ever, but every cargo ship still carries air and water to the ISS. We need to get to virtually 100% recycling before we confidently journey to Mars and beyond into deep space.
  3. Food growth. For space missions to Mars and beyond, bringing prepared food will become less practical. There are currently experiments on the ISS to explore how to grow crops, testing things such as what direction a plant grows without gravity, how to pollinate, and what types of hydroponic soil are best. The ability to be self-sustaining and grow food while in space is just one of the many needed technologies for missions to Mars and future space exploration.
  4. Toll on the human body. Extended weightlessness takes a toll on the human body. There are significant impacts on balance, blood pressure regulation, bone density, and sometimes vision. For astronauts that travel to the Red Planet, there won’t be a ground support team to assist after landing on the Martian surface. The weight and configuration of the Martian spacesuits will also have to allow for the adaptation period to Martian gravity. In addition, the natural environment on the planet’s surface is deadly for human life; the Mars atmosphere has very low air pressure, no oxygen, 96% carbon dioxide, high radiation, and cosmic rays. The habitat and spacesuits will need to protect the crews from the Martian atmosphere.
  5. Lack of communication. Life on Mars will also be psychologically challenging. Even when Earth and Mars are at their closest, 35 million miles apart, it takes radio waves about four minutes to get from here to there. So if the Martian crew transmits a signal to Houston, the quickest they will hear a response from NASA is eight minutes later—worst case is 48 minutes later. Real-time communication will thus be impossible, and the Martian crew will need to know how to be self-reliant, technically and mentally, especially in the event of a dust storm or other emergency.
  6. Determining the right path. The path we take between Earth and Mars needs to be decided. Every day of travel time is another day spent eating food, drinking water, breathing the ship’s air, and producing waste, as well as being exposed to interplanetary radiation and the risk of critical systems failures. If there’s enough fuel, a more direct route could be used, brute-forcing the orbital mechanics. If we invent more efficient engines, we could fire them longer and coast less, also decreasing total time.
  7. Landing carefully. Even if we make it to Mars’s atmosphere, landing presents another set of challenges. Once we’re at orbital speed, we could use Mars’s thin atmosphere to provide braking friction, steering to dip exactly into it to gradually slow to the right speed. But the whole transit ship would need to be tough enough to take the associated heat and pressure. A compromise option might be to jettison the habitat that carried us to Mars, get into a capsule, and ride it directly to the surface. But the Martian atmosphere is much thinner than Earth’s, meaning parachutes don’t work nearly as well. Yet it is thick enough that friction causes heating so the ship needs appropriate heat shielding. The heaviest object we’ve landed on Mars as of 2018 was NASA’s Curiosity Rover (part of the Mars Science Laboratory Mission), which weighs around one ton (on Earth). A crewed ship would weigh much more than a Mars rover. For putting people on Mars, we’ll likely need to use the Martian atmosphere to partially slow down the craft, then fire engines to slow the rate to the surface to the landing site.

How Will Humans Ultimately Get to Mars?

Though getting to Mars would be financially and logistically difficult, scientists believe that it can ultimately be achieved by following a few key steps:

  • Continue exploring the moon. Missions to the moon and Mars are intertwined, as the moon offers a chance to test new tools like life support systems and human habitats that could be used in a future Mars mission. Continued moon exploration is critical to one day flying to Mars.
  • Develop more advanced spaceship technology. There are no space stations in deep space, which means that the ship that takes humans to Mars will need to make the journey without refueling. NASA is currently in the process of developing a solar electric propulsion system to make the deep-space flight. Additionally, the spacecraft will require a deep-space navigation system, rockets strong enough to propel astronauts the length of the journey and back, and landing equipment that works on Mars, which has a thin atmosphere.
  • Design spacesuits to guarantee astronaut safety. The environment on Mars is hostile: its lack of an ozone layer means that there’s no built-in shield against ultraviolet radiation, and the superoxides on the Martian soil may impact humans who walk on its surface. Engineers will need to design protective habitats space suits to prevent harm to the human body.

Want to Learn More About Space Exploration?

Whether you’re a budding astronautical engineer or simply want to become more informed about the science of space travel, learning about the rich and detailed history of human space flight is essential to understanding how space exploration has advanced. In Chris Hadfield’s MasterClass on space exploration, the former commander of the International Space Station provides invaluable insight into what it takes to explore space and what the future holds for humans in the final frontier. Chris also talks about the science of space travel, life as an astronaut, and how flying in space will forever change the way you think about living on Earth.

Want to learn more about space exploration? The MasterClass All-Access Pass provides exclusive video lessons from master scientists and astronauts like Chris Hadfield.

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