One man's childhood interest in space exploration took him all the way to Saturn
Story by HEAMAKARN SRICHARATCHANYA
To John C. Zarnecki, professor of space science at the UK's Open University, January 14 was one of the most memorable days of his life. It was the day that science fiction finally became science fact.That was the date when the Huygens probe successfully landed on the surface of Titan, Saturn's largest moon. Titan is the most distant landing ever achieved _ in a straight line, it's about 1.5 billion kilometres from Earth.As the mission's principal investigator, the professor built one of the scientific instruments to measure the physical properties of the moon. Installed in the probe, his instrument was the first part to touch this new world.``It's a dream come true,'' said the 55-year-old professor who was invited to Thailand last month to join the 100th Anniversary Year of Physics, an event co-organised by the National Science Museum, Ministry of Science and Technology and the British Council, Thailand. ``I didn't dare to think it was possible 15 years ago.''Back in 1990, he was selected to join the Cassini-Huygens space exploration mission, a joint endeavour by the US National Aeronautics and Space Administration (Nasa), the European Space Agency (Esa) and the Agenzia Spazio Italiana (Asi). Named after two celebrated scientists, the mission was designed to shed light on many of the unsolved mysteries of Saturn and Titan.``This is a long, long mission,'' said the scientist who got his doctorate in X-ray astronomy from University College, London. ``So long that two of the scientists sadly died in the meantime.''The reason why this ambitious mission took such a long time was because of the enormous distance involved. It took over seven years for the Cassini orbiter to reach the moon of this ringed planet.The professor explained that the spacecraft could not travel in a straight line because of the limited fuel it could carry. So the solution was to have it fly close to planets to gain energy from their gravitational fields, much in the same way as a slingshot, a technique that has been used for over two decades of space exploration.For its journey, the Cassini-Huygens spacecraft had to fly past Venus twice, then back to Earth and then to Jupiter in order to reach its final destination. Because of this convoluted route, the distance the spacecraft actually travelled was 3.5 billion kilometres.As the Cassini spacecraft reached the orbit of Saturn, the Huygens probe was released, parachuting through the atmosphere of Titan and eventually landing on its surface. It took about two and a half hours for the probe to descend, taking measurements along the way. It survived for just 70 minutes on the surface.``That's it ... 15 years of my life is finished in just three hours,'' said the scientist. His instrument, called the ``surface-science package'', comprised nine sensors to measure a range of surface and atmospheric conditions including temperature, density, refractive index and electrical properties.With the successful landing, what lies beneath the moon's covering of orange fog is beginning to be revealed. And the professor is excited _ since for him Titan is the most fascinating moon in the solar system.``Of over 30 moons of Saturn, Titan is one of the strangest _ not only is it Saturn's largest moon, but it is also the only moon in the solar system that has a [significant] atmosphere.''But a moon with an atmosphere need not support life.``There is no living creature on Titan because of its very low temperature,'' he explained. ``It's minus 190 Celsius out there.''Even so, he said, this mission is scientifically very important.``We think that the atmosphere on Titan is like the atmosphere here on Earth billions of years ago,'' he said. ``So, scientifically, by going to Titan, in some aspects, it's like studying our own history.''The professor then proudly produced a picture of the surface of Titan acquired from the mission. At first glance it looks as if the photo could have been taken on a coastline on Earth, as the scene is full of what looks like sand and rocks.``It might look very boring having waited for over 15 years for this,'' he said. ``But for us, this is a miracle.''He explained that the shots taken while the Huygens probe was descending by parachute were at first sight like pictures of Earth _ there were what looked like rivers, coastline, seas and lakes. But because of the relatively low temperature, what looked like stones were actually ``ice pebbles''. And the lakes are not water but probably liquid methane. Methane is normally in a gaseous state on Earth, but in the low temperature of Titan it becomes a liquid.Most of the scientific data, such as temperature measurements and the amounts of different gasses in the atmosphere, is under study, and Zarnecki said it will take the team several years to go through the data and make sense of it.But how will it benefit our world?``That's always a difficult question to answer,'' he admitted. ``In the absolutely direct sense _ will it save lives directly, will it cure cancer, will it make some fantastic device? The answer is no.''But then again, these are by no means the reason why the mission started, he said.``The exploration [of Titan] will lead us to understand our solar system and our universe better. We want to know about where we live, what's in our neighbourhood, what's over the next hill, what's on the next planet,'' he said. ``It's our little contribution to understanding our planet and it's adding to the body of knowledge in science.''``It'll also lead to developments in technology,'' he said. ``Can you imagine making something to go into space, to travel for seven years and then to work in a place where the temperature is minus 190?''The technology that needs to be developed has to be very reliable, very small and consume very little power, he said.Unlike equipment directly controlled by people, the probe was uncontrollable from Earth _ it was a robot under software control.``So the space programme in general drives us to make certain products better, which in a small, perceptible way makes our life, we hope, better,'' he said.Science has been an important part of Zarnecki's life since he was at school. Stories of Sputnik 1, the first man-made object to orbit Earth, are still vivid in his memory. But his clearest memory of early space exploration was the time when he saw cosmonaut Yuri Gagarin, the first man in space.``School was closed the day he came to London and we went to see him as he was probably the most famous person [in the world] at the time,'' he started. ``The guy was very small because he had to fit in the capsule. He was in a big military uniform and I was standing a few metres from him. I remember thinking that this guy went around the earth once and that it was such a big deal to me.``And that inspired me,'' he continued. ``I thought I'd love to be involved in space.''Since then, space has become his passion.Now that the mission to Titan is over, he is on an Esa committee planning a mission to Europa, one of Jupiter's moons. It is thought that there is an ocean of water below Europa's icy surface and the Esa and Nasa are discussing the possibility of sending a probe there.But because the work is so long-term, he is not sure whether he will live long enough to see its success. ``I may be able to help lay the foundation of the project and contribute to the development of it but it'll be up to the next generation of younger scientists to do what I've done on this mission, to see it through to the end,'' he said.And he would love to see scientists from Thailand involved in such projects.``Some may think that it's such a long way for the Thais to be involved in such a mission but I don't think it's impossible. If you look at this mission [Cassini-Huygens], it's incredibly international,'' he said. ``Even a small country like Ireland is involved.''He said that Ireland is a very small country and although it is considered ``developed'', it is not very rich, but it was still part of the mission.The professor suggests that the Thai government play a role in turning what seems to be an impossible dream into reality.``The government should make some regional ties and give Thai scientists opportunities to work with space agencies since it's very difficult for individuals to go to European space agencies by themselves,'' he said. ``I know there are talented scientists in this country and they should be given opportunities to work internationally.''
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