• Experts say humans must settle on other planets to avoid extinction.
• Long-distance travel and technological hurdles must first be overcome.
• Extra-terrestrial settlers will endure long journeys and harsh conditions.
• Space colonisation is currently being explored by NASA and SpaceX.
• Mars is likely to be the first human settlement beyond Earth.

Where in space could humanity find their future homes? This intergalactic conundrum is at the forefront of nations’ space programmes around the world. Climate change, the threat of even more deadly pandemics, and the likelihood of an Earth-shattering asteroid hit like the one that wiped out the dinosaurs, mean that many are looking at the stars to secure the future of humankind.

Stephen Hawkings, one of the early proponents of ‘space colonisation’ – a politically charged and fraught term linked to the ethical dilemmas associated with human exploitation of extra-terrestrial bodies – saw expansion into space as imperative to humanity’s survival. Space colonisation is controversial because there is fierce debate whether we have the right to use other world’s resources, and our latent potential to pollute other planets. Nevertheless, Hawkins, revising his initial estimate that we had 1,000 years to become a multiplanetary species to avoid extinction, later gave us a mere 100 years.

However, not all futurists and experts agree with Hawkins. Nobel Prize (Physics) winner Michel Mayor, who helped refine the techniques to discover exoplanets, planets outside our solar system, is one such person. Mayor argues that these planets are much, much too far away. He and others suggest that the nearest planet able to harbour life in our galactic ‘neighbourhood’ is likely to still be dozens of light-years away, far beyond the reach of current technology – and human endurance.

As a spaceship accelerates above five Gs (the force we feel when accelerating), most humans, except highly trained experts wearing G-force-reducing suits, will fall unconscious. We can also only withstand five Gs for a grand total of two minutes. Accelerating at a force of nine Gs, a rate at which it would still take 19 days to reach half-light speed, would be fatal. So, will a space in the final frontier that we can call home ever be reached?

How will we get there?

To overcome the huge technological hurdles involved with facilitating the safe passage of human pioneers to other planets, experimental models for long-distance starships have been theorised. As the distance that must be travelled is likely to take longer to transverse than the average human lifespan, even at lightspeed, two options have been proposed for overcoming natural human mortality – hibernating or intergenerational crews.

“The space that must be travelled is likely to take longer to transverse, even at lightspeed, than the average human lifespan.”

The first idea, inducing hibernation mode in the crew, perhaps through cryopreservation or deep freezing, could slow ageing processes to allow spaceship passengers to be ‘thawed’ on arrival. Another idea is a generation ship, where the original crew would not be expected to make it to the final destination but spend their entire lives on the ship, producing children who in turn will eventually produce the antecedents who will arrive at the new planet.

However, more recently, some are looking at the possibility of using laser porting – uploading the human brain onto lasers that are then fired towards a target for long-distance space travel. While it seems strongly in the realm of science fiction, laser porting has powerful supporters. Acclaimed futurist Professor Michio Kaku admits his idea of laser porting is ‘far out’, but sees it as a way of overcoming the vast distances involved and the dangers of space travel on the human body, such as cosmic radiation and extreme G force exposure. Perhaps we really will be asking to ‘beam me up’ when wanting to travel to far-flung corners of the universe.

An inhospitable welcome

Once we finally get there, we are unlikely to be welcomed by anything resembling our home on Earth. Astronaut adventurers are likely to be met with extreme temperatures and weather conditions, similar to those found in our solar system on Mercury and Mars, as well as reduced gravity, suboptimal atmospheres, and perhaps even hostile forms of alien life.

We would also need to install a completely new infrastructure on these virgin planets, securing food and water sources, energy supplies, and building homes to shelter us from the elements. Homes could be built deep underground to protect inhabitants from exposure to giant storms and high levels of radiation. But all this will be in complete isolation from our home on Earth.

Mission to Mars?

Yet perhaps our very first celestial extension into outer space will be much closer to home than a distant galaxy. NASA is already cutting its teeth on technology for making a planet hospitable within our solar system. Mars is currently in the international spotlight as the leading contender for the first human non-Earth settlement. Many organisations, including SpaceX and NASA, are developing manned missions to our solar system neighbour in the near future.

“With 38% of the gravity of Earth and an atmosphere made primarily of CO₂ plants could be grown on Mars.”

Elon Musk, Founder and CEO of SpaceX, also thinks the future of humanity resides on the face of the red planet. With 38% of the gravity of Earth and an atmosphere made primarily of CO₂, plants could be grown on Mars and harvested on this rocky planet, a mere snip away (in space terms) from Earth at just 140 million miles. However, SpaceX points out the planet is ‘a little cold’.

There’s no planet B

However, while the possibility of humans becoming multiplanetary beings in the cosmos is an exciting prospect, it’s not likely to happen anytime soon. Or as the founder of Virgin Galactic (the world’s first commercial spaceflights) Richard Branson succinctly puts it: ‘There is no planet B. We have to take care of the one we have.’

In practical terms, Earth is the only planet we currently have the technology to survive on long-term (because we evolved to its exact conditions). Exoplanets, asteroid belts, and neighbouring moons may in the future host our antecedents and be a solution to cataclysmic mass extinction events on Earth, but today, any such moonshot plans are still in the realm of the strictly theoretical. Within our lifetimes, we are unlikely to see humans settle on exoplanets outside of our solar system, but we may just live to see people on Mars.

Luna Dewey is a freelance writer based in Bristol, UK.