A lack of investment funding may have pushed back the Mars One mission by two years to 2026, according to a recent announcement, but a visit to the Red Planet still fires the imagination as mankind’s next big adventure. Nevertheless, if you read the science, a lack of funding looks like the least of the obstacles would-be interplanetary colonists will have to overcome.
Here are five key obstacles to surmount before a successful colonisation trip to Mars can take place.
During long space missions (such as the extended time spent on the International Space Station) astronauts lose muscle mass and condition, as well as bone density and aerobic capacity, as a result of their exposure to a zero-gravity environment. There are other physiological changes too.
That’s why we often see returning astronauts and cosmonauts needing to be helped from their capsules. Some of these bodily changes can be mitigated through a series of well-structured countermeasures, including exercise and nutrition. One example of this approach was demonstrated during American astronaut Shannon Lucid’s 188-day mission aboard the Russian MIR space station, during which time she relied heavily upon the use of exercise countermeasures. When her mission came to an end, she was able to walk out of the landing vehicle unassisted.
Astronauts travelling to Mars potentially face less of a problem than those returning to Earth because gravity on Mars is 62% less gravity than on our home planet. The Mars One project cites a recent Nasa study of ISS astronauts, with mission durations ranging from four to six months; this indicated a maximum loss of 30% muscle performance (and maximum loss of 15% muscle mass). Mars One suggests that these figures will have improved by the time it is seeking to launch its Mars mission. It also argues that appropriate exercise and pharmaceutical interventions can limit astronauts’ loss of bone density as a result of osteoporosis.
Astronauts heading for Mars will be traveling for a year or more, during which time cosmic radiation could prove to be a serious problem – normally the Earth’s magnetic field protects us from this. One avenue of research is exploring building parts of Mars spaceships, such as the crew quarters, out of cosmic-ray absorbing plastics.
Polyethylene, the same material from which garbage bags are made, absorbs some 20% more cosmic radiation than aluminum, and a form of reinforced polyethylene developed at the Marshall Space Flight Center is ten times stronger than aluminum, and also lighter. Liquid hydrogen is even better at blocking cosmic rays, so it may be that the rocket fuel itself could become the shield.
But what about once the colonists arrive? Mars One says its habitat will be covered by several meters of soil, which provides reliable shielding “even against galactic cosmic rays”. The mission planners suggest that five meters of soil will be able to provide the “same protection as the Earth's atmosphere”.
Our traditional nitrogen and oxygen-rich atmosphere will also be missing on Mars. However, electrolysis of water, splitting it into its constituent elements of hydrogen and oxygen, may be the solution. Mars One says that oxygen will be used to “provide a breathable atmosphere in the living units, and a portion will be stored in reserve for times when less power is available, for example at night, and during dust storms”. In addition, the mission aims to extract nitrogen directly from the Martian atmosphere using a “life-support unit”.
Food and water
Frequent re-supply of food and drink will be too problematic, and expensive, from Earth. However, Mars One is hopeful that colonists will be able to extract water from the Martian soil by heating it and driving off the water, which will be condensed and stored.
Vanguard missions will also deliver storable food from Earth in advance of the first crewed mission, so the original colonists will have some food waiting for them. However, these supplies will only serve as emergency rations, and the astronauts will be expected to eat as much fresh food that they can produce on Mars as possible. The mission planners suggest that algae and insects will form part of the diet on Mars, much of it produced inside under artificial lighting, with some 80 m2 available for plant growth in the original habitat.
The Mars atmosphere is largely composed of carbon dioxide, but one aspect of having a thinner atmosphere is the potential for significant meteor impacts – even smaller rocks won’t burn up on entry as they tend to on Earth. Small space rocks are carving fresh craters into the Martian surface more often than previously thought, researchers say: a new study has found that there are more than 200 asteroid impacts on the Red Planet every year.
The colonists will need to be able to protect themselves and their infrastructure from potential impacts. And if all of that weren’t enough, there is the possibility that Mars remains volcanically active; it is the site of the largest know volcano in the solar system – albeit an extinct one; Olympus Mons stands at about three times the height of Mount Everest….