Should we be thinking about genetic modifications for the humans that we send to colonise Mars?
Pat French
Longdon Upon Tern, Shropshire, UK
No. We cannot know what the optimum characteristics are for life on Mars. We may think that we understand the various Martian environments, but it is certain that our knowledge is incomplete. Also, even unaltered, our species quickly discovers ways to do things that haven鈥檛 been predicted 鈥� for example, the bouncing method of walking on the moon.
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Even if it were to be attempted, it would take generations to establish those genetic changes within a group (to create a specialised genotype).
Supposing that the project started out with volunteers, it would have to impose participation on following generations that had the required genes and reject those children who didn鈥檛. In most societies, this is totally unacceptable.
Over the duration of such an extended project 鈥� prior to the interplanetary journey 鈥� there would be huge changes in our society, technologies, politics and global finance. The effort would be under constant threat.
Any pioneer population that reached Mars might phase out those genes that actively hindered survival
Alternatively, any pioneer population that reached Mars and became established might quite naturally develop useful genes and phase out those that actively hindered survival. Even then, it would take many generations. Further, it would require a society that allowed those not suited to Martian life to die out. Modern humanity supports vulnerable people rather than abandoning them.
It would be much quicker and much more productive to send pioneering machines to Mars well before humans make the attempt. Such machines and robots can be 鈥渆volved鈥� many times in a single human lifetime. By evolving those machines here or on the planet, humans can learn so much more regarding what we might need to survive on Mars as normal human beings.
Mike Follows
Sutton Coldfield, West Midlands, UK
This question has been explored by Kim Stanley Robinson in his Mars trilogy of novels. His first Mars colonisers were called the First Hundred, and they quickly divided into two factions: the Greens were in favour of genetic modification and the Reds were against it. This became a source of tension.
Given that ethnocentrism already exists on Earth based on smaller differences 鈥� including ethnicity, religion and culture 鈥� engineering significant genetic differences might introduce another source of discrimination that could lead to conflict on Mars and between Martians and the people back on Earth. Moreover, each desired attribute would require modifying many genes. The modified genes could interact in unexpected ways, leading to unforeseen health problems or unintended side effects. It might even be the first step towards speciation, though this would require prolonged isolation of the Martian population.
Ionising radiation is one of the most significant risks for humans travelling in space or living on Mars, as the planet lacks Earth鈥檚 magnetic field (which deflects cosmic and solar radiation) and a thick atmosphere to absorb it. Some geneticists, such as George Church, believe that genes can be edited to make humans more resistant to ionisation. Another option may involve incorporating the DNA of other, radiation-hardened species like microscopic tardigrades. Of course, one conventional alternative would be to have colonisers live in subsurface settlements.
Instead of expensive and heavy shielding, astronauts travelling through interstellar space could breathe a cocktail of therapeutic gases to protect against radiation exposure by, for example, neutralising the harmful free radicals it produces. Some professional divers breathe gas mixtures to avoid decompression sickness or nitrogen narcosis. Maybe future astronauts will use 鈥渓iquid breathing鈥�, as depicted in the film The Abyss.
The gravitational field strength on the surface of Mars is 38 per cent that of Earth, which could lead to muscle atrophy and a loss of bone density (osteoporosis). Adaptation of the heart and blood vessels would also be required. While genetic modification is one option, technical solutions are also available, such as generating artificial gravity through the spinning of spacecraft (based on the O鈥橬eill cylinders concept), as depicted by the Endurance spacecraft in the film Interstellar. These spinning cylinders could either be placed in orbit around Mars or positioned on tracks on the surface in the form of spinning cones 鈥� to take account of the planet鈥檚 gravitational pull.
Simon Dales
Oxford, UK
The best 鈥渉uman鈥� for Mars might well be a Dalek. If we are to live entirely in a life-support system, then we need to adapt to that. Their bodies are much smaller and lighter, so fit better into spacecraft. And they have a lower metabolic rate, so provisions last longer.
These Daleks would need a redesigned robot exoskeleton because the traditional sink-plungers on their arms don鈥檛 give good dexterity. Otherwise they would need to bring along some regular humans for fiddly jobs.
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