NOWHERE NEAR IT. But that hasn’t stopped the US promising to have humans living on Mars 24.7/7 (the Martian day is 39 minutes longer than ours). All that needs to be sorted out are the scientific and technical problems in getting there and back in one piece without going hungry, thirsty, dying of radiation sickness, going mad in such a small container with so few people, wasting away or suffocating.
The trip to Mars is at least a six-month jaunt either way, but once there, any Mars explorers will have to keep themselves busy for 18 months before Earth and Mars are again in a suitable position to make the journey home. Food and water can be sent ahead on separate rockets, but six months of supplies will still be needed for the trip out. Since any mission would take between six and eight astronauts, to ensure enough engineers, geologists and medics are on hand, that means a lot of food.
But food may be a minor worry for any Mars-bound astronaut. ‘We still don’t really understand how humans cope with zero gravity,’ says David Williams at NASA’s Goddard Spaceflight Centre in Maryland. ‘Astronauts that have been in space for a year come back and they can’t walk. If you get to Mars and you can’t even walk when you get there, what’s going to happen? At least when they land on Earth, there are medical facilities waiting for them,’ he says.
Astronauts struggle to walk after being in zero gravity because without the pull of gravity, their muscles waste away. Their hearts also weaken as it’s easier to pump blood around the body. So even if humans do get to Mars, they could be physical wrecks on arrival.
Robotic instruments sent to search for life on another planet need to be scrupulously life-free themselves – NASA takes the business of ‘planetary protection’ very seriously and insists on ultrasterile conditions of manufacture. But microbes are very small, difficult to detect and fiendishly well equipped for survival.
A book, Out of Eden, by Alan Burdick, says that a microbe called Bacillus Safensis – said to have evolved to survive within Nasa’s Jet Propulsion Laboratory’s spacecraft assembly facility – is highly resistant to gamma and ultraviolet radiation and can draw energy from the ions of trace metals such as aluminium and titanium.
Its discoverer, Kasthuri Venkateswaran, thinks the bacillus could have travelled to Mars, and survived in the rovers. If so, then some future mission searching for extraterrestrial life could reach Mars, and, embarrassingly, discover a colony of microscopic Earthlings.
But scientists have already discovered Earthlings on another heavenly body. A camera in a Surveyor probe sent to the moon was retrieved by the crew of Apollo 12 almost three years later and shipped back to Earth again. Within the camera were a colony of Streptococcus mitis, a tiny microbe that had inadvertently stowed away. The Streptococcus survived three years in a vacuum, experiencing extremes of heat and cold, without food or water, bombarded by lethal radiation. When it got back to the home planet it revived, and began to multiply.
So, if bacteria can survive in space, perhaps they already have? According to one estimate, Martian rocks hit the Earth as meteorites at the rate of half a tonne a year. The British-born cosmologist Paul Davies – now at the Australian centre for astrobiology at Macquarie University – has argued for years that life could, plausibly, have begun on Mars when the planet was wet and warm, and been exported to Earth inside a lump of Martian shrapnel. In which case, could the colonists have survived, mutated, evolved into complex organisms and 3 billion years later started sending probes to Mars? In other words, did Mars infect us?
Depends what you want to do. If you’re planning to take a ride on a tourist vessel such as Sir Richard Branson’s proposed Virgin Galactic service, the plans are that you’ll need a week, as opposed to the years it takes to train as an astronaut.
What that training will involve is unclear at present but David Ashford, director of Bristol Spaceplanes, reckons that a week is overkill.
‘You could do it in a day,’ he says. ‘All you’re doing is sitting in a seat and you’re strapped in – you’ve got no control over anything. What Virgin Galactic are talking about is a very brief whip up to space and back, being out of the atmosphere for maybe a few minutes.’
The training you need will mainly get you used to the g forces experienced during the trip.
‘When you come back in from space, you pull out of a [steep] dive,’ says Ashford. ‘You’re talking about four or five g for 10–20 seconds. That’s quite a lot. You probably have to go in a centrifuge [in training] to check out you’re OK.’
Prospective passengers will also need a medical exam, but Ashford says this will probably be straightforward. In any case, a lot of the training will be just a precaution.
‘Because this is a new industry, the authorities will start off being cautious and only take fit people and give them a lot more training than they need,’ says Ashford. ‘We’ll find out by trial and error what training, what medical tests are needed.’
Ashford says that if the Virgin plan is successful, it could trigger the far more tantalising idea of developing commercial spacecraft that can go into orbit, and potentially send people into space to stay in hotels there. In this case, passengers would need lots more training. They would be wearing pressure suits (so they’d need to know how to operate those) and would need to be happy with weightlessness by training in aeroplanes on parabolic flights – the so-called ‘vomit comets’.
Ashford says: ‘In 15 years’ time there will be a million people a year going to space hotels.’
The ultimate plan is to build a base and keep astronauts there permanently: a step on from the permanent presence in space afforded by the International Space Station and a practice run for any future adventures to Mars.
NASA plans to get humans back on the moon by 2018, almost 50 years after the Apollo astronauts last walked on it.
Exactly what form the rudimentary moon base will take is still in the earliest stages of planning, but NASA did give some clues. Because taking equipment up into space is so prohibitively expensive, scientists want the astronauts to build as much as they can with materials on the moon itself. The priority for the next decade in space technology, then, will be producing mini-factories which will be able to process the raw ingredients available on the moon.
The day after the space agency unveiled its plans, it announced a $250,000 prize for scientists and inventors to come up with a machine that can excavate the most soil and deliver it to a collector. The digger will be used by robots. They will be dispatched to the dark craters at the moon’s poles to find out if there is water ice there, a source of rocket fuel, oxygen and water to keep crew and equipment going.
The diggers will also mine ilmenite, a mineral from which astronauts can extract oxygen, hydrogen and helium. This could produce air and water, while the flammable gases could be burned to generate electricity.
NASA said the lunar base would provide a ‘huge head start in getting to Mars. A lunar outpost just three days away from Earth will give us needed practice of “living off the land” away from our planet, before making the longer trek to Mars.’
As an event, it’s pretty unique. But historically the transit of Venus has been much more than a mere movement of heavenly bodies. In 1639, astronomer Jeremiah Horrocks unwittingly inflated the size of the universe by using the transit to measure the astronomer’s favourite yardstick, the astronomical unit – the distance from the Earth to the sun. He timed how long Venus took to move across the sun from two different positions, then used trigonometry to work out how far away the sun must be. The answer he arrived at, 90 million km, was nearly 10 times greater than scientists had thought. ‘With that one calculation, he expanded the solar system,’ says Robert Walsh, an astrophysicist at the University of Central Lancashire, Preston. More recent measurements, achieved by bouncing radio waves off the sun and timing how long it takes them to return, have highlighted inaccuracies in Horrocks’s method: an astronomical unit is now known to be around 150 million km.
Galileo is Europe’s planned rival to the ubiquitous, US-owned GPS satellite positioning system. Publicly, it has been touted as a purely civilian system, but some say that it has clear military uses too.
According to Dominique Detain, a spokesman for the European Space Agency (ESA), which is building the system, Galileo has been designed solely for civilian uses, such as tracking ships and delivery trucks.
That doesn’t mean it can’t be used by the military if nation states decide they want to. Like GPS, Galileo will have publicly available signals and more accurate encrypted signals only available to governments.
According to one expert close to the US/European negotiations over Galileo, it is referred to only as a civilian system for political reasons. ‘The official satellite positioning system of NATO is GPS. So British military forces are officially committed to using GPS. So what happens if another military system comes along? It gets very messy and it’s been politically easier for European governments to steer away from it and say it’s not a military system,’ he says.
There is another reason why Galileo’s military potential has been played down. It is written into ESA’s charter that the agency will only work on projects that have non-military uses. Galileo is allowed because it is designed solely for civilian uses, even though it can clearly be used by the military too. ‘Any new tool could be used in that way,’ says Detain.
Some are concerned by China’s 20% stake in Galileo, but Detain says that only EU states will be given the secret codes to use the encrypted and highly accurate signals the satellites will broadcast. Such concerns may be academic, however. Galileo’s publicly available signal will be nearly as accurate as the GPS military signals.
The question is still open – but we now know that Britain’s first spacecraft designed to land on another planet may have vanished into thin air, so to speak. Beagle was designed to sail into the Martian atmosphere on Christmas Day 2003 at 6 km a second, slow down with atmospheric drag, open first a pilot parachute and then the big one, then finally bounce to a standstill in a ball of air bags. Beagle 2 was on autopilot. It was supposed to do things by the clock. So everything depended on scientists and engineers having timed the descent through the Martian atmosphere. Instead, there was silence.
One explanation is that the atmosphere of Mars may not have behaved in the way the models predicted. According to one instrument aboard the European orbiter Mars Express, the air density between 20 km and 30 km from the red planet’s surface was a lot lower than predicted. But according to a different instrument aboard the NASA orbiter Odyssey, it was as predicted, which is why the jury is still out. But the thin-air hypothesis is also supported by the experience of the Americans, who landed two much heavier rovers, Spirit and Opportunity, successfully. Both landed down-range of their target zone, and both parachutes opened later than expected, which suggested that both made faster entries. ‘What that is due to, the Americans aren’t sure,’ says Mark Sims of Leicester University. ‘But it probably is a lower density in the atmosphere.’
If so, that explains why the Beagle team never heard from their baby. ‘There is a whole nest of potential scenarios here. The pilot chute comes out too late and the main parachute comes out too late and we don’t turn on the radar altimeter in time before we hit the surface. Any of these combinations are possible,’ he says.
It isn’t the only possible answer. Maybe space scientists did not really know how to calculate hypersonic and supersonic drag coefficients correctly, always a problem on a different atmosphere 100 million miles from home. If the Beagle team got another chance they might do things a bit differently: fit software that could react to the unexpected, for instance. ‘There is a whole list of things we would change and it just depends on when the next opportunity is and how much time you have to change stuff,’ he says. ‘The bottom line is Beagle 2, on its parachutes, was to land at 16 m per second. If something went wrong high in the atmosphere you would land at 6 km a second, which is a bit different. At that speed there is very little you could do.’
Good question. NASA freely admits it hasn’t got the foggiest. ‘We don’t know,’ says Michael Braukus at the space agency’s Washington HQ. ‘It’s premature right now to be talking about the impact, issues and things like that.’ Which is interesting, as the agency is gearing up for possibly its most controversial launch yet: a spacecraft driven by a nuclear reactor.
NASA has awarded a $400 million contract to Northrop Grumman Space Technology to help design the nuclear-driven Prometheus project, which it hopes will blast off in a decade to explore the icy moons of Jupiter. Nuclear propulsion could send it further and faster with less fuel.
Chris Carr, a space technology researcher at Imperial College London, says that while existing space probes use radioactive power supplies, they are relatively safe because the material cannot trigger an explosive chain reaction if something goes wrong.
‘The problem with a traditional nuclear reactor is that you could not build it strong enough to survive [an accident] because it’s got to have delicate structures.’
According to Seth Shostak at the SETI (Search for Extra-Terrestrial Intelligence) Institute in California, we will. With the current pace of technology, it’s just a matter of time. ‘If you want to estimate when we’re going to hear a signal, it only depends on two things,’ he says. ‘One, how many civilisations are there out there with the transmitters switched on, and secondly, how quickly are we doing our reconnaissance of the sky.’
Working out the first number is, unsurprisingly, the cause of much debate, with estimates ranging from zero to several million. Shostak goes for the more conservative numbers given by the Drake equation, a formulation of factors thought to be required for any life to exist. This suggests around 10,000 civilisations are advanced enough for us to find.
The second problem – how fast we are looking – is a technical challenge. ‘At the moment, we’re going very slowly,’ says Shostak. ‘We check out in the order of 50 to 60 star systems a year.’
‘The bottom line comes out that even if you take Drake’s more pessimistic [ideas], you’ll trip across a civilisation by 2025,’ he says.
There are no hard and fast rules. But the 3,000 km-wide object spotted by American astronomers recently, officially called 2003 UB313 but nicknamed Xena by its discoverers, is a likely candidate for planet status. It is the biggest object found in the solar system since Neptune in 1846.
‘There is no piece of paper which sets down what the definition of a planet is. Terminology is something you’re left with from history and when you make new discoveries; it’s hard to fit things into that terminology,’ says astronomer Jacqueline Mitton.
A number of large objects have been found in recent years, including Quaoar (2002) and Sedna (2004) but neither of these is a planet. The original definition of a planet is a body that orbits the sun. How big it has to be is open to question – asteroids orbit the sun but no one would call them planets. ‘One thing that some astronomers say definitely ought to define a planet is that it’s got enough material in it that it naturally becomes a sphere,’ says Mitton.
While the discovery of Xena is exciting, it casts doubt on the status of the current ninth planet, Pluto. Discovered in the early 20th century, it was given planet status because astronomers had no idea of its origins in a collection of asteroids called the Kuiper belt. Some astronomers argue that if this had been known at the time, it might not have been classed as a planet, but it’s probably too late to change that. ‘There’s a feeling among a lot of the community that it would just be too confusing and upsetting to demote Pluto,’ says Mitton.
The ultimate decision rests with the International Astronomy Union (IAU), which names heavenly bodies. But Mitton says popular will might overtake that decision: ‘If the notion of this being the tenth planet catches on, then it probably will be the tenth planet, whatever the IAU says.’
In space, no one can hear you sing, yet human music has already travelled beyond Pluto to interstellar space aboard Voyager 1 and 2, launched in 1977. These each carried a gold record containing the sounds of Earth – surf, wind, thunder, whale calls, greetings in 55 languages – and music including Bach, Beethoven, Stravinsky, Chuck Berry’s Johnny B Goode and Dark was the night by Blind Willie Johnson.
Had things worked out, humans might have heard Blur blasting from Mars on Christmas day 2003. The band wrote the call sign for the ill-fated British lander, Beagle 2.
Guaranteed interplanetary smash hits headed towards the clouds of Saturn’s mysterious moon, Titan, too. The European probe Huygens delivered, along with a package of sensitive instruments, specially commissioned tracks by Julien Civange and Louis Haéri. These are called Lalala, Bald James Deans, Hot time and No love. They were hits, if only because they slammed into Titan’s clouds at 6 km a second. They went down well – three parachutes guaranteed them more than two hours of airtime. And they have already gone far – 3.2 billion km since their launch.
‘The European Space Agency wanted to add artistic content to the mission, to leave some trace of humanity in the unknown and send a sign to any possible extraterrestrial populations,’ says Civange, who has worked with the Rolling Stones, Simple Minds and David Bowie.
The tradition of bopping across interplanetary space is more than 30 years old. Apollo astronauts were 1960s explorers with 1960s tastes, and in 1972, the last Apollo crew woke up on their final morning on the moon to Richard Strauss’s Also sprach Zarathustra.
Not by sending up Bruce Willis in a space shuttle with a crew of veteran astronauts and oil drillers, that’s for sure. The shuttle can only get to low Earth orbit and anyone who wants to deflect an oncoming asteroid will have to launch years ahead of any impact. So it’s a task best left to an unmanned vehicle, built specially for the job.
Consider the problem: an asteroid on a collision course with the Earth could be detected 10 years ahead. Suppose it to have a diameter of 1 km. Suppose it to be travelling at a relatively sedate 39,000 kph. And suppose it to weigh about 1 bn tonnes. Anything that size hitting the Earth at an angle of, say, 45 degrees would, according to a University of Arizona website (lpl.arizona.edu/impacteffects/) generate the equivalent of a thermonuclear explosion of 50,000 megatonnes, enough to wipe out civilisation as we know it. Such collisions do occur, on average every half a million years. It would be a bad idea just to try to hit the thing with a nuclear warhead: even if the asteroid broke up, it would have time to reform and smash into the Earth anyway. But, experts have been pointing out for the last decade, provided the Earth had sufficient warning, this nemesis could be gently deflected. Last September, Imperial College London’s asteroid expert Matt Genge calculated that something with the mass, acceleration and thrust of a Robin Reliant could push into a billion-tonne asteroid, with an acceleration of a billionth of a metre per second per second. If it did so for 75 days, it would change the asteroid’s velocity by 0.7 cm per second, enough to make it miss its date with the Earth.
Not according to Yang Liwei, China’s first man in space. ‘The scenery was very beautiful,’ Yang told Chinese TV when he returned to Earth. ‘But I didn’t see the Great Wall.’
His comments were taken, in some quarters, as proof that the story about the Great Wall (it being the only man-made structure that can be seen from space) is nothing more than a myth.
In fact, it is a myth, but not because the wall can’t be seen from space. It is actually possible for astronauts a couple of hundred miles up in space to see lots of man-made structures, including skyscrapers, bridges and, weather permitting, the Great Wall.
All Liwei proved is that these objects can be difficult to spot. The Great Wall is especially tricky as it is a similar colour to the surrounding soil and is in a pretty bad state for large stretches. In places, it’s difficult to see the Great Wall of China from China, even at fairly close range.
That’s not to say it’s impossible for astronauts to get a glimpse, and if Liwei wanted tips in finding it he could have asked Ed Lu, who lived on the international space station. ‘It turns out you can see an awful lot from space,’ Lu says on NASA’s website. ‘You can see the Great Wall. I’ve been trying, thus far unsuccessfully, to take a nice picture of it.’
Lu has had plenty of time to take in the sights from the space station windows. ‘You can see the pyramids from space,’ he says. ‘With binoculars you can see an awful lot of things. You can see roads. You can see harbours. You can even see ships.’
Nobody at NASA knows where the idea about the Great Wall came from, but it was doing the rounds before the first satellite was launched. Another variation has it that the ancient stone border, just 6 m across, is the only artificial structure that can be seen from the moon. It can’t. The few astronauts who have been there and looked back at the Earth report seeing a mass of white clouds and blue water, with patches of yellow sand and occasional flecks of vegetation.
They might do, providing you shake the radioactive dust from them before going inside. The anti-fallout footwear is among several tips included in pamphlets passed on to a 1960s population convinced the world was heading for armageddon after the Cuban missile crisis.
The pamphlets suggest several ways of protecting yourself during a nuclear airstrike: stay in a sealed room, avoid going out and, if you do, wear a heavy coat and hat alongside your sufficiently stout shoes. And whitewash your windows to protect against ‘nuclear flash’: the moment when the bomb goes off and spits out intense amounts of heat and light.
Though it might all sound naïve, there is some merit in following these instructions if your neighbourhod happens to be at risk from a nuclear warhead. Nothing can survive a direct attack of course, but if you live several miles away from impact then how you react could save your life.
‘Whitewashing and so forth does prevent a lot of thermal ignition of furniture and draperies,’ says Paul Seyfried, president of Utah Shelter Systems and something of an expert – in theory at least – on keeping yourself safe during nuclear attack. ‘It does go a long way to protecting you from the thermal fault and within about 6–8 miles, the thermal fault is going to cause a lot of bad burns to people who are outside.’
But whitewashing windows or sealing up rooms so that radioactive dust doesn’t get in requires some time to prepare: with advanced intercontinental ballistic missiles, a target city would now be lucky to get more than the classic three-minute warning.
Getting worried? Seyfried designs and builds shelters just for these eventualities. A concrete bunker 8 ft underground would be more than enough to protect against a nuclear attack.
‘The first three days is the real critical part. The rate of decay in the first two or three days is extremely rapid – if you could obtain effective shelter for at least three days, then the chances of avoiding radiation sickness are very good,’ says Seyfried. ‘After two weeks, the fallout radiation is only one percent of what it was an hour after the detonation.’