In the autumn of 1961 I went to Cambridge University, where I had been asked to give a lecture about the chances of travel to the planets.<\/p>\n
I know what I said, because for some reason or other it was recorded.<\/p>\n
I found the tape the other day and in the light of modern research it sounds rather curious.<\/p>\n
Of course, in 1961 planetary space research was still at an early stage, but it did seem to be encouraging. I said \u2013 quite correctly \u2013 that so far as human spaceflight was concerned the only planets within \u2018reasonable\u2019 range were Venus<\/a> and Mars<\/a>.<\/p>\n However, I then went on to say that Venus might well turn out to be the more promising of the two.<\/p>\n The theory of an oceanic Venus, supported by Fred Whipple and Don Menzel, was a popular one: we thought we might find a world which was not unbearably hot, and where life might have appeared in the seas, just as it did on Earth so long ago.<\/p>\n Mars, on the other hand, was cold, dry, lifeless and more or less airless, with polar caps built up on an inch-thick layer of solid carbon dioxide.<\/p>\n<\/div>\n As we now know, the surface temperature on Venus is intolerable, the carbon dioxide atmosphere produces a crushing surface pressure, and far from being aqueous, the clouds are rich in sulphuric acid.<\/p>\n As I have said before, anyone going to Venus must be prepared to be fried, squashed, poisoned and corroded.<\/p>\n This brings us back to Mars, which is less unattractive than it seemed to be in 1961.<\/p>\n There is only a tenuous atmosphere, but the thick polar caps are due mainly to water ice, and there is a definite chance of low-type life, even though Percival Lowell\u2019s canal builders have been consigned to the realms of myth.<\/p>\n Controlled landings have been made, and as I pen these words, NASA\u2019s Spirit and Opportunity rovers<\/a> are moving around, sending back superb images and masses of data.<\/p>\n We have learned a great deal since I gave that talk at Cambridge.<\/p>\n What we have not done is to find out whether or not Mars is totally sterile, and here the rovers cannot help us.<\/p>\n Meanwhile, our own mission, Beagle 2<\/a>, sent back no signals after landing.<\/p>\n Further missions have not only been planned, but funded.<\/p>\n They are not cheap, but a robot probe costs less than a nuclear submarine, while the money spent on operations in occupied Iraq would fund all space research well into the 22nd century, and perhaps even the 23rd.<\/p>\n The most ambitious vehicle so far described is the brainchild of the European Space Agency.<\/p>\n It is known officially as ExoMars<\/a>, though it seems to have acquired the name of Bridget. Launch is scheduled for 2011, with touchdown on Mars in 2013.<\/p>\n The complete spacecraft will consist of a carrier module and a descent module, launched by a Soyuz-Fregat vehicle.<\/p>\n Separation will occur after the two-year \u2018cruise\u2019 from Earth to Mars, and the descent module will land in a suitable area, yet to be chosen.<\/p>\n The six-wheeled rover will then be deployed, and begin its long research programme.<\/p>\n Its instruments will include some designed specially to search for life.<\/p>\n There will be a drill able to penetrate 6ft (2m) below ground level, which will carry a \u2018life marker chip\u2019.<\/p>\n This will contain biological molecules which can easily combine with other organic molecules as soon as they come into contact.<\/p>\n If Martian organisms do exist, they are likely to be below the surface, shielded from the radiation which bombards Mars constantly.<\/p>\n Of course, by the time ExoMars begins its search, the earlier probes may have told us whether any traces of life really are present.<\/p>\n Since we cannot hope to find anything as intelligent as a worm, some people will certainly wonder why we are so interested.<\/p>\n The answer is quite straightforward: we know that many stars possess planetary systems and that there must be many planets where life could appear.<\/p>\n But even if it could appear\u2026 will it?<\/p>\n If it has done so on Mars, the answer is \u2018yes\u2019 and it follows that life is almost certainly common all over the Universe.<\/p>\n We will have to admit that there is nothing unusual about the Earth, or about ourselves, and we will be forced to do some radical rethinking.<\/p>\n I wonder how our learned religious leaders would react? They would have to face up to some very knotty problems.<\/p>\n If the plans for sending humans to Mars go ahead, we must decide whether there are any insuperable objections.<\/p>\n Technically, it may be said that there are not, but radiation is a serious threat.<\/p>\n Humans have stayed in orbiting stations for many months without suffering serious harm, but circling a few tens of miles above the Earth cannot be compared with a journey millions of miles into space.<\/p>\n If an emergency arises, the Martian traveller cannot turn round and come home; there can be no Apollo 13<\/a>-type manoeuvre.<\/p>\n<\/div>\n The fact is that if we aim for Mars, we must realise that there will be casualties, and public opinion has to be taken in to account.<\/p>\n Fewer people have lost their lives in the early period of astronautics than in the corresponding period of aeronautics, but what would have happened if Apollo 11<\/a> and Apollo 12<\/a> had crashed?<\/p>\n![\"""\"](\""https:\/\/images.immediate.co.uk\/production\/volatile\/sites\/25\/2020\/05\/JAXA-Venus-copy-02ab05e.jpg?quality=90&resize=620%2C423"\" "\\"\"\"\\"\/")
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