Giant leaps for mankind

By Lord Martin Rees



As technology allows us to gaze further into space, it’s a dangerous delusion to think that it offers an escape from Earth’s problems. We’ve got to solve these here, writes astronomer royal Lord Martin Rees. Coping with climate change may seem daunting, but it’s actually a trivial task compared to terraforming Mars.

Last July marked the 50th anniversary of the Apollo 11 moon-landing. I never look at the Moon without being reminded of Neil Armstrong’s words, "One small step". The achievement of the Apollo astronauts remains the ‘summit’ of manned spaceflight. It seems even more heroic when we realise how it depended on primitive computing and untested equipment. The last Apollo mission was in 1972; since then, hundreds of men and women, from many nations, have gone into space, mostly in the International Space Station. But these flights have been restricted to circling the Earth in a low orbit, and are far less inspirational.

Indeed, odd though it may seem, Apollo’s most durable and influential legacy was the image called ‘Earthrise’ — taken by the US astronaut Ed Anders while in orbit round the Moon — showing Earth’s delicate biosphere, contrasting with the sterile moonscape where the astronauts left their footprints. 

Space technology has nonetheless burgeoned in the last five decades. We depend routinely on orbiting satellites — some weighing many tonnes, others smaller than a shoebox — for communication, sat-nav, environmental monitoring, surveillance, and weather forecasting. Space telescopes orbiting far above the blurring and absorptive effects of Earth’s atmosphere have beamed back images from the remotest cosmos. 

Importantly, the cost of launches has come down; moreover, spacecraft can be miniaturised, using the technology developed for smartphones. In consequence, space is no longer an enterprise for governments or mega-corporations. It’s a frontier open to private ventures from all nations.

During this century, the entire solar system — planets, moons, and asteroids — will be explored and mapped by fleets of tiny automated probes, interacting with each other like a flock of birds. And robotic fabricators will construct, in orbit, vast solar energy collectors and telescopes. Some entrepreneurs envision manufacturing in space, or mining of asteroids for precious metals. 

“there may be a billion planets in our Milky Way resembling the Earth”

Lord Martin Rees

But none of these activities need to involve human astronauts. There’s no denying that NASA’s Curiosity, a vehicle the size of a small car that has been trundling across a giant Martian crater since 2011, may miss startling discoveries that no human geologist could overlook. But machine learning is advancing fast, as is sensor technology. In contrast, the cost gap between manned and unmanned missions remains enormous. The practical case for manned spaceflight gets ever weaker with each advance in robots and miniaturisation.

Nonetheless, I hope some people now living will walk on Mars, as an adventure, and as a step towards the stars. I think they will be privately sponsored, not funded by taxpayers. Those who go will be adventurers, prepared to participate in a cut-price programme far riskier than governments could impose on publicly supported civilians. SpaceX, led by Elon Musk, or the rival effort, Blue Origin, bankrolled by Jeff Bezos, will soon offer orbital flights to paying customers.

These ventures — bringing a Silicon Valley culture into a domain long dominated by NASA and a few aerospace conglomerates — have shown it’s possible to recover and reuse the launch rocket’s first stage, presaging real cost savings. They have innovated and improved rocketry far faster than NASA or ESA has done. There will be many more space-faring nations in coming decades. But the role of national agencies will be attenuated, becoming more akin to an airport than to an airline, and the role of private enterprise will expand. 

The phrase ‘space tourism’ should be avoided. It lulls people into believing that such ventures are routine and low-risk. And if that’s the perception, the inevitable accidents will be as traumatic as those of the Space Shuttle (which suffered two crashes in 135 launches, but had been presented to the American public as ‘safe’). These kinds of exploits must be ‘sold’ as dangerous sports, or intrepid exploration.

By 2100, thrill seekers in the mould of, say, Felix Baumgartner (the Austrian skydiver who in 2012 broke the sound barrier in free fall from a high-altitude balloon) may have established ‘bases’ independent from the Earth, not just on the Moon but on Mars too. Elon Musk (born in 1971) of SpaceX says he wants to die on Mars, but not on impact! But don’t ever expect mass emigration from Earth. And here I disagree strongly with Musk, and with my late Cambridge University colleague Professor Stephen Hawking, who enthuse about a rapid build-up of large-scale Martian communities. It’s a dangerous delusion to think that space offers an escape from Earth’s many problems. We’ve got to solve these here. Coping with climate change may seem daunting, but it’s a trivial task compared to terraforming Mars. No place in our solar system offers an environment even as clement as the Antarctic or the top of Mount Everest on our own planet. 

There’s no ‘Planet B’ option for ordinary risk-averse people. But we (and our progeny here on Earth) should cheer on the brave space adventurers, because they will have a pivotal role in shaping what happens in the 22nd century and beyond.

The space environment is inherently hostile for humans. So, being ill-adapted to their new habitat, the pioneer settlers on Mars will have a more compelling incentive than those of us on Earth to redesign themselves. They’ll harness the super-powerful genetic and cyborg technologies that will be developed in coming decades. These techniques will be, one hopes, heavily regulated on Earth, on prudential and ethical grounds, but these pioneers will be far beyond the clutches of the regulators. We should wish them good luck in modifying their progeny to adapt to alien environments. This might be the first step towards divergence into a new species. Genetic modification would be supplemented by cyborg technology: indeed, there may be a transition to fully inorganic intelligences. So, it’s these space-faring adventurers, not those of us comfortably adapted to life on Earth, who will spearhead the posthuman era.

Organic creatures need a planetary surface environment, but if posthumans make the transition to fully inorganic (electronic) intelligences, they won’t need to have an atmosphere. And they may prefer zero-g, especially for constructing extensive but lightweight habitats. So it’s in deep space, not on Earth or even on Mars, that non-biological ‘brains’ may develop powers that humans can’t even imagine. And if they are near-immortal, they wouldn’t be daunted by prolonged voyages into deep space  — far beyond the distant boundaries of our Solar System — to populate the realm of the stars. 

Will these intrepid explorers from Earth find life out there already? Will there be life on Mars, or under the ice of Europa, one of Jupiter’s moons? There is a possibility — it’s certainly worth a search, although we know for sure that there is nowhere else in our solar system that harbours advanced life. 

If we widen our horizons to the realm of the stars, the prospects are far brighter. One of the greatest scientific advances of the last half-century has been the discovery that most stars are orbited by retinues of planets, just as our Sun is orbited by the Earth and the other familiar planets. Indeed there may be a billion planets in our Milky Way resembling the Earth, the same size, and at a distance from their parent star such that water neither boils away nor stays frozen. These exoplanets are too faint to be studied by existing telescopes. However, in coming decades we will build vast lightweight telescopes in space. Such instruments will be able to image ‘Earths’ orbiting nearby stars. 

It’s a reasonable hope that by the year 2068, the centenary of the famous ‘Earthrise’ photo taken by the Apollo 11 team, we'll have an equally iconic image of another Earth orbiting a distant star.

Will these other worlds have continents and oceans, even vegetation and a biosphere? Could some even harbour alien intelligent beings? These are challenges that could take many centuries to answer, but it’s a cosmic quest that will continue to fascinate all humanity.