I was old enough to watch the TV images of the first moon landings. I can't look at the moon without thinking of this exploit. It was achieved 12 years after Sputnik-1 was launched. There would have been footprints on Mars a decade or two later if that momentum had continued. Many of our generation expected that. The era of the space race between the United States and the USSR was when Nasa absorbed up to 4% of the US federal budget. There was no motivation to continue this expenditure after the race was won.

These exploits are not new to young people. Space technology has advanced. We depend on satellites for a lot of things. Pictures of varied and distinctive worlds have been beamed back by robotic probes to other planets. Our knowledge of the universe has been greatly improved by telescopes in space. It is more likely that humanity is on the verge of an era of space exploration that makes the moon landings seem parochial by comparison.

The last two people to visit the moon, Harrison and Eugene, came back in 1972. Hundreds of people have gone into space, but no one has done more to circle the Earth than the International Space Station. The scientific and technical payoff from the ISS is not trivial, but it has been less cost-effective than robotic missions. These voyages are not as inspiring as the Soviet and US adventures were.

The space shuttle was the main vehicle for transporting people to and from the International Space Station. It failed in 135 launches. The astronauts or test pilots would accept less than 2% of the risk. The shuttle was promoted as a safe vehicle for civilians, despite the fact that one of the casualties of the Challenger disaster was a female teacher. Each failure caused a national trauma in the US and was followed by a hiatus while costly efforts were made to reduce risks still further.

Our solar system will be explored by flotillas of miniaturised probes during this century. The wonderful Cassini probe was launched nearly 25 years ago and spent 13 years exploring the planet and its moons. In the future, huge, gossamer-thin mirrors for telescopes or solar energy collectors may be built using raw materials mined from the moon or asteroids. Even in high altitudes, the robots could repair the craft.

Humans are no longer needed in space due to advances in artificial intelligence. The fact that the Apollo 17 astronauts was a geologist allowed them to collect samples of lunar rocks and soil. Future probes will be able to make their own decisions. Why send a human if you can get a robot to do it? I hope people follow the robots as explorers rather than for practical goals.

The Silicon Valley culture has been brought into the domain by private- enterprise ventures such as Blue Origin. They have been able to cut costs. They can be less risk-averse than a western government, and still find volunteers willing to tolerate higher risks. These cut-price ventures with private sponsorship should be at the forefront of human space travel.

The phrase "space tourism" should not be used. It makes people believe that such ventures are routine and low-risk. The inevitable accidents will be as traumatic as those of the space shuttle were. These exploits must be promoted as dangerous sports or intrepid exploration. The brave thrill-seekers of the future may well establish bases independent of the Earth. Musk, the richest man on the planet, wants to die on Mars, but not on impact.

What is the long-range goal? The first settlers on Mars would be followed by millions of others. This is not a good idea. Mars is terraforming compared to the climate crisis. Nowhere in our solar system can you find an environment like the top of Everest. Most of us won't have a planet B. I want to cheer on those pioneers because they will have a big role to play in shaping the future.

The pioneer settlers are ill-adapted to their new habitats, so they will have a more compelling incentive to redesign themselves. They will harness the super-powerful genetic and cyborg technologies that will be developed in coming decades. One hopes that these techniques will be heavily regulated on Earth, but not on Mars. We should hope that they can modify their offspring to adapt to alien environments. This could be the first step towards a new species.

The post-human era will be led by these space-faring adventurers, not those of us who have been adapted to life on Earth. It may be in deep space, not on Earth, or even on Mars, that non-biological brainpower can develop powers that humans can't imagine.

The sun will last six billion more years. The expanding universe will continue for a long time. If intelligent life had started on the Earth, it could jump-start a diaspora that would spread through the whole universe. Interstellar voyages would not hold terrors for near-immortals.

Even though we are not the terminal branch of an evolutionary tree, we humans could claim significance for jump-starting the transition to electronic entities, spreading our influence far beyond the Earth. Will our remote offspring be the first intelligences to spread through the universe? Will they see something that is already out there, where evolution had a head start over us?

  • The astronomer royal is a former president of the Royal Society. The End of Astronauts: Why Robots Are the Future of Exploration is his new book.