When Elon Musk announced his Mars mission and to build a colony there by 2050, I was fascinated by the idea of having a planet other than the earth becoming a colony of human civilization. It is something like the science fiction stories that I loved to read during my childhood are coming true.
In the last few decades, science and technology have been so advanced that we are now planning for extraterrestrial life. But the question is - will it be easy for us to develop a colony on another planet with our existing technology? Certainly, it will not be easy, but, is it going to be actually feasible for us to colonize a hostile planet like Mars? This is a very important question and must be addressed with great care before starting a trillion-dollar project on an alien world. In this article, I try to point out only a few of the many basic points which challenge us to have a home on Mars.
Cosmic Rays: The presence of a magnetic field around the earth saves us from high-energy charged particles that are continuously coming from the sun and outer space – called cosmic rays. These cosmic ray particles are not able to reach the earth's surface because these are deflected away in other directions by the magnetic field by an effect called Lorentz force. Since there is no such natural magnetic field present around Mars, the cosmic rays continuously bombard over the Martian soil and anything standing on it. Cosmic rays can damage DNA molecules if exposed and therefore it is extremely dangerous for humans. The cosmic rays coming from outer space are called galactic cosmic rays, and these can penetrate easily a thick metallic wall. So, not only do the mars stations have to be cosmic ray proof, but also the mars-suits that they need to wear when working outside. The spacesuits that our astronauts wear today cannot completely prevent the galactic cosmic rays and therefore to work in the Martian environment for a long period of time is not yet possible.
Energy Requirement: Probably energy requirement is going to be the most challenging aspect of establishing and then running a colony on Mars. As there is little oxygen in the Martian atmosphere, we shall have to depend upon artificially generated oxygen for breathing which will continuously require lots of power. Further, the surface temperature of Mars is well below –60o Celsius during the nighttime even in the equatorial region and therefore an artificial temperature maintenance system is necessary. This will also require lots of energy. The idea of green housing on Mars is not as much efficient as on Earth because of the less solar power that Mars receives being at a distance from the sun which is 1.5 times that of the earth from the sun (i.e. the average distance of Mars is 1.5 AU from the sun). Also for maintaining the temperature, we cannot use any burning process as that will increase oxygen consumption which is unwanted. Therefore we must depend upon electric power. These are a few examples but sufficient to realize that we need to generate a lot of electric power every day for running a colony on Mars.
The main methods of generation of electric power on Earth are - hydroelectricity, wind-electricity, thermal power, and solar power. Hydroelectric power is not possible on Mars because it needs flowing water. Wind electricity will not be much efficient on Mars because of very thin Martian air. Thermal electricity is theoretically possible if heat is produced by a nuclear reactor, but it is not cost-efficient to construct a nuclear reactor on Mars in the initial stage. So, chiefly we have to depend upon solar power. But as Mars is on average 1.5 times farther from the sun than from Earth, we will be able to generate (1.5)2 times less average power generated by a solar panel of the same size on Earth due to the inverse square law of flux. Apart from this, Mars's dust storms are also a big challenge for the solar power generation on the planet. So, it's going to be quite difficult to generate electric power continuously on Mars. NASA is trying to develop a new technology called Radioisotope Thermo-electric Generator (RTG) for extraterrestrial applications, but large and continuous power generation by using this process is yet to be developed.
Food: Next big challenge will be with the food supply. As a return trip to Mars is going to be quite costly, food supply to the Mars stations from the earth is not possible. So, future Martians must develop their own farm on Mars for food. Obviously, 100% farming has to be done within an airtight greenhouse and non-veg farming is not a good idea as it will increase oxygen consumption (so Mars is suitable for vegans (?)). As plenty of liquid water is needed for farming, a water recycling unit is required. All the cereals and vegetables that we grow on Earth will not perhaps grow on Martian soil because of its composition and therefore choice of food will be limited. Those who are planning for mars are definitely going to miss pizzas and burgers. For longer stays, this can be irritating because on Earth we are habituated to a variety of foods.
Communication to Earth: Sunlight comes to Earth with a delay of 8 minutes due to the distance. Similarly, due to the distance between Earth and Mars which changes between 0.37 AU to 2.6 AU, there is a delay between transmission and reception of radio signals between Earth and Mars. On average it takes about 12 minutes to receive a radio signal at Mars after it is sent from Earth and vice-versa. With such a huge delay in communication, this is going to be impractical to have live communication with someone on Earth. While this may not affect the scientific goal of the mission as the Martians will be trained to take decisions by themselves whenever necessary, this will definitely affect social communications with the people on Earth and in the long run, this may have a negative psychological impact on the first peoples of Mars.
Gravity: This is a very important issue for colonizing Mars. The human body is designed for an earthly environment where we are habituated to a certain force of gravity due to Earth. In principle, we can develop all other things in a closed chamber on Mars similar to Earth but the gravity. On Mars we will experience 2.7 times reduced gravity than Earth. That is, a person weighing 60 Kg will feel a weight of 22.2 Kg on Mars. The effect of low gravity on the human body for a long time exposure is likely to give some negative effects such as reduced bone density, lesser muscular strength, etc. and therefore one way trip to Mars does not seem to be a good idea.
Manpower: On Earth, we have been able to develop such a huge and advanced civilization because we are here in good numbers and work together to achieve a big goal. With less manpower, this would not have been possible. On Mars too it would not be possible to develop a colony and run it for a long time with a limited number of people (also we cannot send a very large number of people at a time). However advanced robots may help, but we are yet to develop a robot that can behave like a human in all respect.
Local resources: Availability of local resources is very important for colonizing Mars. We are able to build large numbers of constructions and production lines here on Earth because the raw materials needed are available on Earth and would not be possible if we needed to import the same from a distant planet. Similarly for colonizing Mars, we have to depend upon local resources to fulfill our requirements. For example, for nuclear power generation, heavy water D2O is used as a moderator. On Earth, D2O is present in normal water in a very small proportion which is extracted in a complicated process, and therefore it is a costly chemical. Fortunately, D2O is present in Martian water (in the form of ice mixed with soil) in a good proportion and therefore nuclear power might be a good choice on Mars in this respect, but, the same D2O rich water is not suitable for drinking purposes as it is known to slow down the metabolism process and may create a health hazard.
These are a few points of many - which show that colonizing Mars is going to be a difficult task for our present civilization, and many decades are yet to go to develop the required technology. Hope Elon Musk and his company SpaceX are not going to put people's lives at risk by claiming that it is going to successfully establish a colony on Mars by 2050.