Nasa’s Webb telescope is a joy. But it’s the private ventures that push at limits

After years of delay, and massive cost over-runs, the James Webb space telescope (the JWST) was launched on Christmas Day. It will need to perform complex automated operations now it’s in space.

The first and most challenging is happening this week: unfurling a heat shield the size of a tennis court. After this, its 6.5-metre mirror must be assembled from 18 pieces packed within the launching rocket’s nose-cone. There’s much that can go wrong and astronomers will remain anxious for the several months that will elapse before all necessary manoevres and tests are completed.

After the Hubble Space Telescope was launched more than 30 years ago, its mirror turned out to be poorly aligned. But astronauts undertook a “rescue” mission to make adjustments and later made further visits to upgrade the instruments.

The stakes are higher for the JWST: it’s vastly more elaborate, but there is no prospect of a repair mission. The Hubble telescope was in a low (and accessible) orbit: in contrast, the JWST’s orbit will be several times further away than the moon – far beyond the reach of astronauts. Some might argue that we therefore need to instigate more ambitious plans for human spaceflight: to enable human assembly of large structures in deep space, to return to the moon, and eventually to reach Mars. But I don’t share this view. Indeed as robotics and miniaturisation improve, the practical and scientific case for human spaceflight weakens. Its prime motive now is simply as an adventure – an ultra-expensive sport that should be left to billionaires and private sponsorship.

Space technology has burgeoned – for communication, environmental monitoring, satnav and so forth. We depend on it every day. Unmanned probes to other planets have beamed back pictures of varied and distinctive worlds. And telescopes in space have revolutionised our knowledge of the cosmos.

During this century, the whole solar system will be explored by flotillas of miniaturised probes, far more advanced than, for instance, Nasa’s wonderful Cassini probe, which spent 13 years exploring Saturn and its moons. This was launched 20 years ago and based on 1990s technology. Think how much better we could do today. Robotic fabricators will assemble vast lightweight structures in space (huge, gossamer-thin mirrors or solar energy collectors, for instance), maybe using raw materials mined from the moon or asteroids. And they could repair spacecraft in orbit far beyond the moon. Robotic and AI techniques are evolving fast. For instance, the Curiosity vehicle sent to Mars a decade ago trundled slowly across a Martian crater; if it encountered a rock, it needed instructions from Earth about how to divert its path. In contrast, Perseverance, which landed on Mars last February, has sufficient intelligence to find its way around obstacles. In another decade, such a probe will have AI sufficient to identify and explore interesting sites and geological formations.

Nasa’s programme for human spaceflight, ever since Apollo, has been impeded by public and political pressure into being exceedingly risk-averse. The space shuttle failed twice in 135 launches. Thrill-seekers would willingly accept this 2% level of risk. But the shuttle had, unwisely, been promoted as “safe”. So each failure caused a national trauma and was followed by a hiatus while costly efforts were made (with very limited effect) to reduce the risk. Because of this safety culture, Nasa will confront political obstacles in achieving any grand goal within a feasible budget.

But private enterprise ventures – SpaceX, Blue Origin and the rest – bringing a Silicon Valley culture into a domain long dominated by Nasa and a few aerospace conglomerates, can cut costs and tolerate higher risks than a western government could impose on publicly funded civilian astronauts. So it’s these ventures, with private funds and sponsorship, which should front manned missions. The phrase “space tourism” should be avoided. It lulls people into believing 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. These exploits must be sold as dangerous sports or intrepid exploration.

Don’t ever expect mass emigration from Earth. And here I disagree strongly with Elon Musk and with my late colleague Stephen Hawking. It’s a dangerous delusion to think that space offers an escape from its problems. We’ve got to solve them here. Coping with climate change is a doddle compared to terraforming Mars. Nowhere in our solar system offers an environment even as clement as the Antarctic or the top of Everest. There’s no “Planet B” for ordinary, risk-averse people. Nonetheless, this century courageous thrill-seekers may establish bases independent from the Earth. Musk himself says he wants to die on Mars – but not on impact. Although we may not want to join these space adventurers we should cheer them on. This is why. They’ll be ill-adapted to Martian conditions, so they’ll have a compelling incentive to redesign themselves. They’ll harness the super-powerful genetic and cyborg technologies that will be developed. These techniques will, one hopes, be restrained on Earth, on prudential and ethical grounds, but settlers on Mars will be 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.

So it’s these spacefaring adventurers, not those of us comfortably adapted to life on Earth, who will spearhead the post-human era, evolving within a few centuries into a new species. (This evolution, proceeding on the timescale of technological advance, is potentially thousands of times faster than Darwinian selection.)

Moreover, if they make the transition from flesh and blood to fully inorganic intelligences, they won’t need an atmosphere. And they may prefer zero-g, especially for constructing massive artifacts. So it’s in deep space – not on Earth, nor even on Mars – that non-biological “brains” may develop powers that humans can’t even imagine.

The sun will survive 6bn more years before its fuel runs out. And the expanding universe will continue far longer, perhaps for ever. So even if intelligent life had originated only on the Earth, it need not remain a trivial feature of the cosmos: it could jump-start a diaspora whereby ever more complex intelligence spreads through the whole galaxy, via self-reproducing machines, transmitting DNA, instructions for 3D printers or suchlike. Interstellar voyages would hold no terrors for near-immortals. There’s plenty of time ahead.

Martin Rees is astronomer royal