The End of the Space Shuttle Program

So NASA's Space Shuttle has flown for the last time - and the USA is set to wait maybe more than a decade before it can send humans into Earth orbit again. But do we need to?

We're now told the universe is probably going to carry on expanding - so there's no need to rush. In a few billion years the Sun will explode, but that still gives us lots of time. Mars - and space - are not going to go away.

Life on Earth started anaerobically, then made the leap to an oxygen-rich environment and colonised the waters of the Earth, going through several iterations to reach homo sapiens. At each of these stages, life moved on into an environment unsuited to previous life - and couldn't move back. It took billions of fish and millions of mudflats for something to crawl ashore - and almost everyone got left behind. homo sapiens is not the final stage in that progression - just the current stage. It's time for it to happen again - for carbon-based organised life to give way to silicon-based organised life. This time, of course, we will be the ones left behind.

And here we sit, naïvely scanning nearby stars for Earth-like planets. Why? We can never get there, and there's no proof they're the only places life can start. They've probably got tenants anyway.

Even fleeting consideration of a manned mission to Mars ought to tell us something obvious. Hard vacuum, weightlessness, long missions and high radiation levels are serious issues for homo sapiens. So is life support - the food, water and fuel for a six-man return expedition would weigh 15,000 tonnes - sixty Shuttle launches. Both interplanetary space and Mars itself are cold places - keeping warm is a major part of the issue. And the Shuttle cost a fortune - not least in terms of human life, at over one death per ten missions. We're not designed to leave our atmosphere, just as the anaerobic bacteria wouldn't last too long on the viewing gallery of the Empire State Building.

And Newt Gingrich wants the Moon to be the American Rockall

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We need to iterate. What we do is not repopulate the ISS but robotise it - develop our space-faring successors in the environment they will have to live in - radiation-rich, cold hard vacuum. Without humans and held at a lower temperature, the ISS would be power-rich. A rack-mounted processor could do the thinking, and something like a remote-controlled blimp could do the work. But no need for buoyancy and no limits on mass - who cares if it takes hours to move about with its little fans? One of the problems we've solved in the last few decades is software updating - what used to take a small army of high priests weeks goes unnoticed on our televisions and smartphones.

And there's a minor incentive to prepare for maintaining the JWST - any missions like the Hubble repairs will have to be unmanned. Lagrange 2 is a sod to get to, quite hard to get away from, and very very cold - that's why we chose it. Send a robot and leave it attached to the JWST - any propellant left over will come in handy too. If it's currently not designed for robotic docking, someone has some work to do. And the JWST may even need refueling for an extended mission one day - Plutonium 238 has a short half-life.

The current GRAIL programme simply wouldn't be possible with humans aboard the spacecraft - even our heartbeats would disturb its instruments.

So mechanise the ISS. Remove the humans and replace them with autonomous machines. It's an ideal testbed - complex but close enough for a Soyuz to reach if there's a serious problem. Our concepts of what intelligent machines will look like has changed over the years - C3PO is a 1930s concept repopularised by the Star Wars throwback. Robo sapiens won't look like us - and they very likely won't look much like each other. Take a look at a construction site - not every vehicle is a bulldozer. A huge variety of life fills a huge variety of niches on Earth - robo sapiens will be no different. How long will it be until we add another domain to the phylogenetic tree of life - Mechanica?

After all, a homing pigeon doesn't need legal knowledge, and a sheepdog doesn't need calculus. A smartphone doesn't need a map of the world to direct me to the nearest doctor. One limiting factor of biological life is that reproduction always results in a close copy of the parent. This is a terrible restriction on exploring lifeforms. Animal life on Earth is incredibly diverse - beetles especially - and mechanical life will have to be just the same.

Descendants of IEEE 802.11, Bluetooth and NFC will replace speech and robo sapiens won't turn "Send reinforcements, we're going to advance" into "Send three and fourpence, we're going to a dance". Every robo sapiens will know at every instant what every other robo sapiens knows. They'll never understand the Comedy of Errors.

Robo sapiens would have one great trait that homo sapiens doesn't - infinite patience. So it takes 50,000 years to cross the gulf to the next star? Time for a nap. Time is one of the massive cosmic scales, and one to which we humans are as unsuited as hard vacuum and temperatures close to absolute zero.

If you don't need food, water, oxygen, warmth and a return transport system, and you can withstand solar radiation and high G forces, mining on Mars becomes easier. The minerals you need are easier to find - who cares if there's water at the poles? Who needs water? In fact, without both water and free oxygen, corrosion problems go away. Robots don't even need clean laundry. This also redefines 'habitable planet' to mean anything with a solid surface and a nearby star.

Using the lowest-energy Hohmann Transfer, there is a launch window to Mars every 26 months and the trip takes about 9 months - that's a one to three year wait for any critical spare parts, not including mission preparation. It's a long time to wait if you're consuming fuel, food, water and oxygen all that time - but a machine can just switch itself into standby mode. There's another reason a Mars mission wouldn't just be 'Apollo on steroids' - Mars has no 'free return trajectory'. The Moon missions were designed so that the spacecraft, absent any other influence, would sling-shot back to Earth. A feature of great utility to Apollo 13 but not available to any Mars mission.

We shouldn't be shy of the robotic approach - to date we've been quite successful. Voyager 1 is now so far from Earth that round-trip radio signals take a day and a half - Opportunity has been roaming on Mars 35 times longer than intended. Cassini looks like operating at least nine years beyond its original end of life.

It looks as if someone at least is thinking this way - the current NASA budget proposals provide for restarting the production of Plutonium 238 - essential for long solar system missions.

Future missions will be even more challenging. Just as the JWST will only be repairable by robots, so will future Mars probes. These missions are becoming more capable and more costly - it's time to think of rovers as assets. One strategy would be to overlap them - wait until the MSL fails, and send the next mission to repair it and then continue with its own tasks. Repeat this enough times and the surface of Mars will be populated. We'll have to land them close enough together, though - hard to argue when scientists want variety.

It may be, of course, that we won't get the choice. Over time and even on Earth we're gradually building more capable robotic systems. We sometimes dismiss them as trivial - Apple's Siri or Google Goggle's Sudoku solver. But the trend is only going in one direction - one day these systems will be significantly more intelligent and capable than the very best of our elected officials. What then?

The Meaning of Life? There isn't one - it's a chemical accident. Boringly, everything we see is explained by chemistry and physics. And everything we can't see doesn't exist. The interesting issue is whether organised life can proceed from here to colonise the universe - and maybe one day influence it.

Finally two quotes. From the Guardian:

We'll never be able to get a man standing on the surface of Venus, but when it comes to exploring Mars a single human will be able to do the work of hundreds of robots.

Not borne out by the track records of Spirit and Opportunity, both of which stayed on Mars and made more observations than any human could do. Another quote, this time from Arthur C. Clarke in Hazards of Prophecy:

When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.

Here's a thought as whacky as any Asimov Foundation thought - maybe millions of years from now our silicon descendants will revere Earth as 'the home of Google'. For them, by that time, it may well have the status of a god. Better earned than any of the gods of our own prehistory - instead of worshipping their creators, they will know of our weaknesses, painfully short lives and low intellects. And wonder at how we created Google. Perhaps we will one day get to Mars. As pets.

Until then, all that most of the human race can do is drive the technology. Keep buying the iPhones, people.

Unless, of course, you're very rich indeed. And you know how to find asteroids made of platinum.