Anyone who watches Channel 36 - Ovation, the Arts Network - will have heard Arthur Clarke say, in one of those self-promotion ads they run, that he would rather go to Mars than the Moon, because Mars is where all the action is.

I hadn't realised quite what he meant until I paid a visit to NASA's Internet pages a few days ago. Would you have guessed that there have already been 31 missions to Mars, launched by various countries and combinations of countries, three of which are still up there? I certainly wouldn't. The fuss about Mars seems a comparatively recent phenomenon, and I'd have said there might have been a dozen attempts only to get there.

Many of those 31 missions seem to have been a part of the Space Race that the US and the USSR were involved in during the Cold War. On the face of it, the Russians, particularly, were jumping the gun a little. They tried unsuccessfully six times to fly past Mars before the US succeeded with Mariner 4 in 1965. They tried again three times, also unsuccessfully, before they got Mars 3 down to the surface in 1971.

Even that success was limited, because Mars 3 managed to get only a small quantity of data and some pictures back to the USSR. It wasn't just the Russians who were trying to move too quickly - the history of Mars exploration is littered with failures - 19 of the 31 attempts failed on the launch pad, couldn't get beyond earth orbit, were lost in space, were lost on arrival or got where they were going and simply failed to send data back.

The US Mariner 4 gave us our first close-up look at Mars. That was exciting stuff back in those early days of space exploration.

But the jewel in the crown of Mars exploration, and perhaps of all space exploration so far - the discovery that there is water on Mars - was made very recently. Just a few weeks ago, in June, researchers using Mars Odyssey, one of the vehicles currently in orbit around the planet, found water ice under the surface of the planet. The reason this is so important, of course, is that water and life go together. Was there once life on Mars? Is there life on Mars now?

These are heady questions. A third is even headier - can Mars support human life? It may sound like something out of one of Arthur Clarke's novels, but it is a serious question. The four stated goals of the Mars Exploration programme are first, to determine whether life ever existed there; second, to characterise the climate of the planet; third, to characterise its geology; and fourth, to prepare for human exploration of Mars. Those of us who grew up in the middle of the last century weren't consulted about this, or we'd have given the programme a fifth goal, looking for evidence of the existence of "Ming the Merciless" and "The Mekon". Wouldn't we?

Just a few days ago, on August 2, researchers published, in the journal Applied and Environmental Microbiology, the results of a study of the material contained in a 4.5 billion year-old Martian meteorite. They claimed that 25 percent of it had to have been produced by ancient bacteria on Mars. That water ice Mars Odyssey found, together with a carbon dioxide-rich atmosphere, would have provided just the environment to support the evolution of the kind of microbes found in the meteorite.

This lends a kind of spicy urgency to the process of looking for further evidence of life. The three spacecraft currently either on their way or in orbit around Mars were designed to look at the climate and the geology of the planet.

Mars Global Surveyor, launched in November 1996 and currently in orbit around the planet, is busy making high resolution maps of the planet, and gathering information about its surface and atmosphere. It may also be used to relay information back to earth from future Mars missions.

Mars 2001 Odyssey, which found the ice evidence, was launched in April 2001 and is also currently in orbit around the planet. It, too, is mapping the Martian surface, using three different systems to look for minerals, to look for elements in the Periodic Table and to establish the radiation environment of the planet.

Nozomi (the Japanese word for hope) was launched under the direction of the Japanese Institute of Space and Astronautical Science in July, 1998. It had a propulsion problem, and is now in orbit around the Sun. But it is expected to continue on to Mars late next year, and will be studying the Martian upper atmosphere and its interaction with the solar wind. It is also being used to develop technologies for use in future planetary missions.

There are another eight missions scheduled to fly in the next few years. Two of them are scheduled to leave next year, one in 2005, one in 2006, two more in 2007 and the last two in 2011. The two leaving next year are both going to land instruments on Mars. Mars Express is leaving in June, and the 2003 Mars Exploration Rovers are set for launch sometime between May and July.

Mars Express is a mission being planned by the European Space Agency and the Italian Space Agency, in which NASA is participating. Its main objectives are to search for subsurface water from orbit, and to deliver the lander, Beagle 2, to the surface. Beagle 2 is going to be doing exobiology and geochemistry research.

Exobiology is the process of determining the history of the biogenic elements (Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous and Sulphur) from their birth in stars to their incorporation into planetary bodies like Mars. Geochemistry involves chemical analysis of elements of the surface of the planet.

NASA's current big project is the 2003 Mars Exploration Rovers, whose principal task is to land two new rovers, similar to the rover landed by the 1997 Mars Pathfinder mission, but much more powerful. Each rover is going to be carrying a set of instruments that will allow it to search for evidence of liquid water that might once have been present. The two rovers will be dropped off in different areas of the moon.

NASA is still fine-tuning the design of these little buggies - if you have time this afternoon at about 3 p.m. (which is 11 a.m. Pacific Daylight Time), pay a visit to www.exploratorium.edu/marsrover.

There is going to be a half-hour telecast there of a prototype rover - FIDO - bouncing around in a desert somewhere. The tests, which were secret, have been running since August 6 and end today. These particular machines will weigh more than 300 pounds apiece, and be capable of crawling a little more than 300 feet a day.

They will be capable of analysing what they find, of course, even cracking rocks open with a new tool that has been designed for them. They will also be carrying a 360-degree camera so that we here on Earth will be able to see what they see there on Mars.

This is not easy stuff - as we have already learned. Mars does not have a tidy surface - it is full of canyons and craters and volcanic mountains. To get to the surface, these little rovers have to slow down very quickly from orbital speed of 13,000 miles an hour. To do that, they'll be using the same airbag system that Pathfinder used.

The really interesting stuff, though, will come on later missions. NASA is planning robotic moles that one day soon are going to land on the surface and burrow down between 30 and 60 feet a day to depths of perhaps thousands of feet, looking for water and measuring temperature change.

In truth, the first mole is going to be carried down to the surface of Mars next year, on board Beagle 2, the European Space Agency's rover. But it is going to be limited to drilling down only two or three feet, a depth at which it seems unlikely there might be flowing water.

Another exciting set of experiments will be done on the surface of Mars in the next few years, using life detectors. This technology involves uses imaging devices, like X-rays, to look inside things like rocks to detect life; or using broad-band fluorescence to identify carbon-based chemistry that could be associated with life.

This kind of experiment will mean building instruments that are smart enough to make a series of measurements, process the data and then decide, on their own and without prompting, which measurements to make next. Impressive.

But you know, exciting though these missions are going to be, intelligent though all this business of space exploration is, I think I still prefer the 1950s approach - send Buck Rogers or Dan Dare up there with a ray gun, back some little alien into a corner and demand to be taken to his leader.

It was good enough for the British Empire, why shouldn't it damn well be good enough for Space?

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