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RDT info logoMagazine on European research Special issue - February 2007   

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Title  The revolutions of offshore science

For David Southwood, Director of Science at ESA, there are two main kinds of space science. One looks outwards, from our own solar system to the edges of the universe. The other focuses on Earth. Both are related to a threefold question concerning the existence of life: why, how and where?

David Southwood
David Southwood, Director of Science at ESA: “Observation from space is now permanently used to understand the way the Earth’s ecosystem and its sub-systems function. It reveals a number of essential phenomena which it would be impossible to see in any other way.”
Space science is an area of research which involves the expenditure of sums that appear quite staggering. Is Europe right to devote so much energy and so many resources to it?
Let’s be realistic. Europe hasn’t gone into space primarily to do science. The ability to put satellites in orbit is now an essential strategic and economic tool in telecommunications, navigation, security, etc. It’s a major issue of independence. A few centuries ago a modern nation had to have a fleet and be able to send its ships from one continent to another. In the same way, we have to be able to send our spacecraft wherever we want.

But once we have this capacity, we can also use it for scientific purposes. To abstain from such activity would be absurd, at a time when advances made in our fundamental and practical understanding thanks to space exploration are playing a decisive role in so many different fields. Europe is now a major player in global research; it has vast human scientific potential. It has a role to play in scientific research, a realm where we must be capable of travelling ‘wherever we want’.

What are the scientific objectives of ESA?
Space travel allows us to enjoy two distinct scientific perspectives. One looks outward and is interested in understanding the universe in which we exist and from which we have originated. The other looks downwards, observing this object called Earth, to which we owe our existence. In that first outward-looking perspective the key area of interest is, of course, the exploration of our own ‘neighbourhood’, our solar system, more and more of which is now within the reach of our spacecraft. ESA currently has an Express probe in orbit around Venus and another around Mars. The joint Cassini-Huygens mission of 2004-2005 is a success: the NASA craft is in orbit around one of Saturn’s moons, Titan, on which the European probe Huygens landed without a hitch. And of course we shouldn’t overlook Smart 1, a satellite which has been examining the surface of our own moon since 2004, hoping to establish whether water was ever present there.

At the same time Europe has made an important contribution to the search for comets, initiated 20 years ago with the visit of the Giotto probe to Halley's Comet, an important first for the European space programme. The comets were formed before the planets and may be the primal matter from which the planets were created. Of course, this matter has been heated, subjected to collisions, combined with other matter – we need to understand these processes if we are to recover the original ‘building blocks’. This is the great ambition being pursued at present by the Rosetta probe, launched in 2004 and scheduled to touch down on the comet Churyumov-Gerasimenko in 2014. The probe takes its name from the Rosetta Stone, which allowed Champollion to decipher Egyptian hieroglyphics. It is our ambition to decipher the codes governing the evolution of matter in the solar system – the matter from which life itself was born.

The north-east coast of Sri Lanka as seen by Envisat after the tsunami of 28 December 2004 (above) and the damage caused by this catastrophe as recorded by ERS-2. The north-east coast of Sri Lanka as seen by Envisat after the tsunami of 28 December 2004 (above) and the damage caused by this catastrophe as recorded by ERS-2.
The north-east coast of Sri Lanka as seen by Envisat after the tsunami of 28 December 2004 (above) and the damage caused by this catastrophe as recorded by ERS-2.
But space does not stop at the edge of the solar system…
Far from it. Beyond the solar system there is the enormous field of observation opened up to astronomers and astrophysicists by telescopes and detection equipment mounted on satellites orbiting the Earth. The vast array of images of the stars sent back by the Hubble ‘observatory’ is well known, but there are other, less well known instruments, such as XMM-Newton, a craft dedicated to picking up X-rays, which have gathered vast amounts of data of enormous value to scientists.

ESA is currently engaged in preparations for a number of projects which will continue the fascinating exploration of space. In two years we will be launching – on the same rocket – the Planck and Herschell probes. The first will study, in some of the most remote galaxies, the formation of the universe in its earliest stages, as its structure first took shape – in other words, the period closest to the Big Bang. The second will analyse the organisation of matter in large masses, the formation of the galaxies, stars and planets. Herschell will be an instrument that casts light on the mysterious dark side of the universe, where gravity transforms mass into heat as certain stars collapse in on themselves. Next it will be the turn of the Gaia mission, which is designed to delve deep into the heart of the intricate cosmic mechanisms of our own galaxy, its billion stars, its dark matter, etc.

Don’t these projects tend to make you neglect the observation of the Earth?
Not at all. The ‘Living Planet’ programme, which brings together all the various means we use to observe the Earth, represents about half of all ESA's efforts in scientific research over the next few years. Observation from space is now permanently used to understand the way the Earth’s ecosystem and its sub-systems function. It reveals a number of essential phenomena which would be impossible to see in any other way. Over the last three decades, Europe has been amassing irreplaceable expertise and knowledge through its deployment of more and more meteorological satellites, through the dispatch into orbit of the ERS (European Remote Sensing) 1 and 2 satellites and above all through Envisat, which is the jewel in the crown of all our means of terrestrial observation. It is a satellite platform from which no fewer than ten instruments have been scrutinising the oceans, the icecaps, the continents and the atmosphere since 2002.

‘Living Planet’ is the roadmap laid down by ESA in order to fulfil its mission in the now vital context of climate change and global warming. A series of six satellites, the Earth Explorers, are on the drawing board or already under construction and will be launched between now and 2012. Each of them will have its own set of tasks to perform, carefully adapted to meet the needs of the ‘doctors’ of the Earth, promoting better understanding of the great sea currents, ocean salinity, the water cycle, atmospheric circulation, the melting of the icecaps, etc. All this will proceed independently of the development of meteorological satellites, as well as the satellites which will form part of the much-publicised GMES system (Global Monitoring for Environment and Security).

The Spainsat satellite in place on top of the Ariane 5 rocket.
The Spainsat satellite in place on top of the Ariane 5 rocket.
© ESA/S.Corvaja
When you open the ESA website the first link you see is an appealing one for the visitor: it’s called Life in Space. Is it not this underlying question of whether there is ‘life on other planets’ which makes space so compellingly fascinating to mankind?
Well, we already know that there is 'life on Earth’... When we observe the Earth from a spacecraft aren’t we already in fact observing ‘life in space’? And it’s high time we did so too. We know that global warming and climate change are processes which will challenge the relations between life and our planet, processes which raise the whole question of Man’s responsibility towards ‘his’ planet.

And this relationship also determines the way we look outwards into space. The possibility that our own Earth might one day become uninhabitable is a powerful inducement to studying how the massive greenhouse effect prevents any life forms on Venus and to ascertaining whether, despite its inhospitable appearance, Mars might not harbour some form of primitive life. On Titan, hydrogen, methane, nitrogen and water have been detected... Now if that water were to release its oxygen all the conditions might be in place for life to evolve. What’s more, the possibility is now opening up of studying other planets outside our own solar system – a prospect which would have been dismissed as science fiction just twenty years ago.

What science tries to understand is how all this – the universe, life on Earth, perhaps life on other planets – first appeared. If the universe were to be born again there is no certainty that human life would emerge again on a planet no more important than any other, in a galaxy itself surrounded by other galaxies stretching to infinity in all directions.

Science also has some idea of how the whole story of the universe will unfold in the future. One day, five billion years from now, the sun will have become a red giant and will have swallowed the Earth. Perhaps our planet is the only life-containing region in our own particular universe. Or perhaps this same universe is literally crawling with life …There’s a moral significance to this. In a certain way, if we are indeed unique, then our survival is of particular importance. But if, on the other hand, we are just one example of life among thousands of others, then it is less important. When the time comes we would be able to let the lights go out in peace…

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