For our future in space, China must aim further than the Moon

Dec 19, 2013 by Martin Rees, The Conversation
Is China our only hope? Credit: Alexander F. Yuan/AP

A famous picture in the English edition of Newton's "Principia" shows cannon balls being fired from the top of a mountain. If they go fast enough, their trajectory curves downward no more steeply than the Earth curves away underneath it – they go into orbit. This picture is still the neatest way to explain orbital flight. Newton calculated that, for a cannon-ball to achieve an orbital trajectory, its speed must be 18000 miles per hour – far beyond what was then achievable.

Indeed, this speed wasn't achieved until 1957, when the Soviet Sputnik was launched. Four years later Yuri Gagarin was the first human to go into orbit. Eight years after that, Neil Armstrong made his "one small step". The Apollo programme was a heroic episode. And it was a long time ago – ancient history to today's young people.

Had the momentum of the 1960s been maintained over the next 40 years, there would be footprints on Mars by now. But after Apollo, the political impetus for manned spaceflight was lost.

The most crucial impediment to space flight stems from the intrinsic inefficiency of chemical fuel, and the consequent requirement to carry a weight of fuel far exceeding that of the payload. This is a generic constraint, based on fundamental chemistry. If a planet's gravity is strong enough to retain an atmosphere, at a temperature where water doesn't freeze, and metabolic reactions aren't too slow, the energy required to lift a molecule from it will require more than one molecule of .

Launchers will get cheaper when they can be designed to be more fully reusable. It will then be feasible to assemble, in orbit, even larger artifacts than the International Space Station. But so long as we are dependent on chemical fuels, interplanetary travel will remain a challenge.

To infinity and beyond? Probably not NASA. Credit: NASA

Nuclear power could be therefore be transformative. By allowing much higher in-course speeds, it would drastically cut the transit times to Mars or the asteroids. And it could transform manned spaceflight from high-precision to an almost unskilled operation. Driving a car would be a difficult enterprise if, as at present for space voyages, one had to program the entire journey beforehand, with minimal opportunities for steering on the way. If there were an abundance of fuel for mid-course corrections (and to brake and accelerate at will), then interplanetary navigation would be a doddle – indeed simpler than driving a car or ship, in that the destination is always in clear sight.

In the light of this, I would venture a confident forecast that during this century, all the planets, moons, and asteroids of the solar system will be explored and mapped. The Hubble Telescope's successors, with huge gossamer-thin mirrors assembled under zero gravity, will further expand our vision of stars, galaxies and the wider cosmos.

But the role that humans will play in this is debatable. There's no denying that NASA's "Curiosity," now trundling across Martian craters, may miss startling discoveries that no human geologist could overlook. But robotic techniques are advancing fast, allowing ever more sophisticated unmanned probes. And the cost gap between manned and unmanned missions remains huge. The practical case for gets ever weaker with each advance in robots and miniaturisation. Indeed, as a scientist I see little purpose in sending people into space at all.

But as a human being, I'm an enthusiast for . I hope some people now living will walk on Mars – as an adventure, and as a step towards the stars. They may be Chinese: China has the resources, the dirigiste government, and maybe the willingness to undertake an Apollo-style programme. And China would need to aim at Mars, not just at the Moon, if it wanted to assert its super-power status by a "space spectacular."

However, NASA's manned programme, ever since Apollo, has been impeded by public and political pressure into being too risk-averse. Unless motivated by pure prestige and bankrolled by superpowers, manned missions beyond the Moon will need perforce to be cut-price ventures, accepting high risks – perhaps even one-way tickets. Such missions would need to be privately funded. No Western governmental agency would expose civilians to such hazards.

Nonetheless, a century or two from now, there may be small groups of pioneers living independent from the Earth – on Mars or on asteroids. Whatever ethical constraints we impose here on the ground, we should surely wish these adventurers good luck in genetically modifying their progeny to adapt to alien environments. This might be the first step towards divergence into a new species: the beginning of the post-human era.

And machines of human intelligence could spread still further. Whether the long-range future lies with organic post-humans or with intelligent machines is a matter for debate. Either way, dramatic cultural and technological evolution will continue not only here on Earth, but far beyond.

Explore further: SpaceX to bid for rights to historic NASA launch pad

add to favorites email to friend print save as pdf

Related Stories

Bid to colonize Mars wins high-profile backing

Dec 10, 2013

A Dutch entrepreneur's bold quest to colonize Mars won high-profile support Tuesday from a US aerospace giant, although the timetable for putting humans on the red planet has been pushed back two years.

China plans next manned space mission for summer

Feb 28, 2013

China will send three astronauts on a mission to its orbiting space station this summer as part of preparations to establish an even larger permanent presence above Earth, the manned space program said Thursday.

Recommended for you

Astronauts to reveal sobering data on asteroid impacts

8 hours ago

This Earth Day, Tuesday, April 22, three former NASA astronauts will present new evidence that our planet has experienced many more large-scale asteroid impacts over the past decade than previously thought… ...

Rosetta instrument commissioning continues

9 hours ago

We're now in week four of six dedicated to commissioning Rosetta's science instruments after the long hibernation period, with the majority now having completed at least a first initial switch on.

Astronaut salary

9 hours ago

Talk about a high-flying career! Being a government astronaut means you have the chance to go into space and take part in some neat projects—such as going on spacewalks, moving robotic arms and doing science ...

Red moon at night; stargazer's delight

Apr 16, 2014

Monday night's lunar eclipse proved just as delightful as expected to those able to view it. On the East Coast, cloudy skies may have gotten in the way, but at the National Science Foundation's National Optical ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

dbsi
4 / 5 (1) Dec 19, 2013
What I'm missing in this outlook is the power of commercially driven programs like Mars One, orbital tourism or simply the commercial launchers.

More news stories

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Hubble image: A cross-section of the universe

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history. They range ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...