Challenge: sending a manned mission to Mars. Due date: 2030 or later. Dangers: many. Obstacles: almost incomprehensible. What technologies are still required for colonization of the red planet?

As the race for launching a manned mission to Mars progresses, more and more questions arise regarding the challenges and dangers participants will face during the journey – the journey itself, the landing and of course living and surviving on the red planet.

The journey to Mars will be long. According to NASA, a manned journey will take about 240 days using current technology, providing that the time slot during which Earth and Mars are at minimal distance between one another, occuring once every 26 months, is exploited. Novel technologies will shorten the journey by 100 days, but this will still mean spending several long months in space.

Astronauts undergo strenuous training before going into space. As early as the launch, the g-force, gravitational acceleration, exerted upon the astronauts rises to 3gs, i.e., three times the gravitational force at sea level. The higher the g, the more force the heart requires for pumping blood through the body, and at 4gs most people will lose consciousness due to a drop in blood pressure.

One of the major concerns with taking this long journey is radiation. In space, as opposed to Earth, there is no atmosphere to block the radiation coming from space. Engineers are still trying to find solutions for protecting passengers from the strong radiation that they will be exposed to during the long journey. NASA has even suggested astronauts freeze their sperm or eggs in fear their fertility will be damaged by the radiation. 

A recent paper, published in the Proceedings of the National Academy of Sciences journal, alleviates some of that fear. The researchers kept a frozen mouse sperm sample on the International Space Station for nine months, and then used it to fertilize eggs. They did not find any difference between the pups that were born from the sperm sample sent to space and the control sample that stayed on Earth. Though the sperm's DNA was slightly damaged due to the stay in space, the egg corrected these errors during fertilization. Researchers are also testing the effect of radiation on plant seeds in order to find resilient plants that will survive the long journey, which will allow agricultural development in the distant world.

Nevertheless, it is important to bear in mind that the International Space Station is 300-450 km from Earth, which is pretty near, so it still benefits from the protection of the Van Allen radiation belts. The belts are comprised of charged particles that orbit around the Earth, and kept in place due to its magnetic field. Only one percent of the particles is not skewed by the magnetic field and reaches the atmosphere. A journey to Mars will involve crossing the Van Allen belts and traveling beyond them, namely, the spacecraft will pass an area with much higher radiation than the International Space Station.

סלעים על מאדים
Rocks on Mars. Photograph by the rover Curiosity. Credit: NASA/JPL-Caltech/MSSS

Reaching Mars

After traveling for months in space, the astronauts, who will already be able to see Mars through the spacecraft window, will be facing a new challenge – landing. To date, space probes that landed on Mars used parachutes for slowing down before landing and airbags for protection. For larger probes, researchers have developed a sort of flying crane that allows gradual lowering of the research probe onto the surface. However, a manned spacecraft will weigh about 20 tons, and so far technologies that can bring such a weight to the surface of Mars have not been developed.

The site of landing will be determined ahead of time, and as we speak, NASA is already exploring locations that will allow the crew members to settle and explore the area. In a NASA-hosted workshop two years ago, researchers discussed 47 suggestions for different landing sites, looking for sites that will provide an appropriate landing environment and reasonable living conditions.  

What will happen after landing? Well, the average temperature on Mars is about -60 degrees centigrade. In summer, the temperature during the day can reach as high as 20 degrees at the equator, but at night it drops well below zero. The atmospheric pressure on Mars is less than one percent of that at sea level on Earth. This means that liquids, such as water (as well as blood, which mostly consists of water), will boil at much lower temperatures than those we are familiar with. Even in areas on Mars with above-average atmospheric pressure, water boils already at 10 degrees centigrade. Therefore, it will be necessary to use protective gear whenever stepping outside of the work station. This poses the challenge of making more durable and less cumbersome suits than those we saw in the landing on the moon.

חליפת החלל החדשה של נאסא
New NASA spacesuit from January 2017. Credit: NASA/Cory Huston

Life on Mars

The aim of the first missions to Mars will be to learn how to live and survive on the distant planet. These missions will probably include setting up a residence and a laboratory, both of which have to primarily provide the crew with protection from the temperature changes and radiation, as well as be self-sufficient.

In 2016, NASA chose six companies to design a prototype for the working and living facility and gave them two years to perform the research and build the first model. A building like this will have to address critical life-protection issues, such as safety measures, air supply, energy etc.

There are countless risk factors. Researchers from the University of Edinburgh in the UK have recently discovered that there are more dangers in radiation than previously thought. These dangers stem from chemicals coming on the surface of Mars that enhance the effect of radiation, which is already high due to the thin atmosphere. 

In a laboratory study, researchers exposed these chemicals to radiation that is similar to the one found on Mars. Exposure to these radiated chemicals resulted in vast bacterial cell death. One solution to this problem is building the residences under the ground, but that would require sending heavy digging machinery from Earth, which is not possible today. In the past, researchers have suggested launching a few unmanned missions with robots before human arrival to the planet, in order to build the required infrastructure for the manned mission. 

Aside from safety, the companies developing the residence will also have to address the issue of maintaining the crew members' mental health. The mission to Mars, including the trip itself, will be a very long one, and during all of that time the crew members will be staying in small and crowded spaces. Research shows that people may develop claustrophobia, or fear of closed places, and other psychological disorders following a long time in space and in confined spaces. In order to minimize the danger, the living and working environments will have to not only be compact and light-weight, but also provide crew members with sufficient personal space and privacy.

Simulations being conducted on Earth are attempting to decipher the possible effect a long stay in space will have on humans. For instance, every year, the the Mars Society, a non-profit organization that aims to promote research about Mars, holds simulations in a special isolated building in the Utah desert in the USA. Roy Naor, an Israeli graduate student has even participated in one of the latest simulations.

NASA is also attempting to better their understanding of how a long stay in space influences astronauts. A twin study, which began in 2015, is testing how spending one year in space affected the astronaut Scott Kelly, by comparison to his twin brother, who is also an astronaut and stayed on Earth during this time. Aside from psychological effects, researchers are also testing changes in gene expression between the twins.

רעיון לסביבת מחיה בחלל
Idea for a living environment in space. Credit: NASA

Self-sufficiency in a foreign world

Longer missions to Mars and establishment of a permanent colony pose additional challenges. One of the most complex tasks is food supply. Since relying on a constant supply from Earth is not a possibility, the new Martians will have to grow their own food in specialized greenhouses.

They will also require a constant supply of medication, and one solution to that can be producing it in a lab on Mars. Researchers from the Netherlands have recently developed an efficient and simple method for utilizing solar energy for executing chemical reactions. The researchers managed to create artificial silicon leaves that absorb different magnitudes of radiation, but then use just the amount of radiation required for the chemical reaction, emitting the extra. This may allow the settlers to produce drugs and even chemicals that can be used in agriculture. 

The first manned NASA mission to Mars is only planned for the 2030's, about 20 years from now, and it seems the list of questions and difficulties just keeps getting longer. Even now, it is clear that the first passengers are not facing a relaxing vacation, but rather a journey of survival and discovery – just like the great explorers, but with different scenery. The main question that arises is whether the allocated time is sufficient for development of new technologies and gaining deep knowledge about Mars, so that we can handle the many challenges in store.

A recently posted video on the AsapSCIENCE youtube channel provides a short and mostly ominous overview of the dangers that await travelers to the red planet:

Translated by Elee Shimshoni