December 26, 2013
By Richard Gray, Science Correspondent
The biggest digital camera in the world was recently launched into space to produce the most detailed map of our galaxy ever created
The £630 million Gaia Space Telescope will take three dimensional pictures of more than a billion stars in the Milky Way in an attempt to help astronomers pinpoint our location in the galaxy for the first time.
Scientists claim the spacecraft, which is due to be launched in October, will allow them to study the stars around us in more detail than ever before and will reveal just how far these distant suns are from our own solar system.
The telescope will help astronomers determine the age, size and movement of the stars like never before while also provide details about what they are made of.
They also hope to discover more than 5,000 new planets outside our own solar system along with other objects that lie outside our galaxy.
“Gaia is an astronomers dream,” said Alvaro Gimenez, director of science at the European Space Agency, which has funded the mission.
“It is designed to answer many of the questions we have about the stars around us.
“It is easy to see stars at night be we know little about exactly how far they are, who they move, what they are made of and how old they are. Gaia is gong to tell us this.
“By looking at the dynamic structure of our galaxy we will be able to learn about its formation and something about its future.”
The car-sized spacecraft, which has been built by space company Astrium, is expected to launch in October from French Guiana on a Russian Soyuz-Fregat rocket.
It will take a month to travel nearly one million miles from Earth towards the sun to the location where it will begin taking pictures.
Once there it will unfurl a 30 feet wide “skirt” that will help to shield the spacecraft from the sun’s rays that could damage it and impair the quality of any pictures.
Solar panels on the back of the sun shield will also help to provide power for Gaia during its five year mission to photograph the galaxy.
Its “eyes” consist of two mirror telescopes that will give Gaia stereoscopic vision much like human eyesight and allow it to see in 3D.
A camera sensor with more than a billion pixels will record the images captured by the telescopes. The average camera on a mobile phone has around 10 million pixels and is just a fraction of an inch in size.
Gaias camera sensor measures one and a quarter square feet and is made up from 106 light sensitive electronic chips.
Nasa’s Hubble Space Telescope, which has been the most successful ever launched, has a camera sensor of just 16 megapixels.
With such a high resolution camera, Gaia will be able to peer more than 150,000 light years away, or 900,000 trillion miles into space. The camera is powerful enough to be able to distinguish a single hair more than 430 miles away.
Professor Gerald Gilmore, UK principal investigator on the Gaia mission based at the University of Cambridge, said: “The 3D aspect of this telescope is vital.
“Embarrassing we only have accurate distances for 719 stars out of the billions in our sky after 1,500 years of astronomy.
“Until now it has only been possible to determine the location of the stars on a flat plain. Gaia is going to be able to tell us about how far away those stars are and how they are moving.
“It is something we will never be able to do on earth because the atmosphere blurs everything and introduces colours.
“Gaia is going to open our eyes to layers of information that we can only dream of.”
It is estimated that there are more than 100 billion stars in the Milky Way and our solar system sits on one of the arms of the spiral of stars that form the galaxy.
Although Gaia will only be able to image around one per cent of the stars in our galaxy, it will take pictures of each around 70 times to build up a picture of how they are moving with its stereoscopic vision.
By looking at how the stars move over time, astronomers hope to pinpoint the exact position of our own solar system while also building up a picture of how our galaxy is growing.
The pictures beamed back to Earth are expected to produce enough data to fill 1.5 million CDs.
Scientists also hope to detect supernova – enormous exploding stars – and quasars, the supermassive black holes that are thought to sit at the centre of galaxies.
Professor Gilmore added: “It will be the first time we have explored distant space in this way so there are a lot of things that we will be able to do.
“As the information comes in we should be able to spot new supernova as they happen, planet transits and there will probably be new things that we don’t even know about yet that will be discovered.
“Giai will provide information on entirely new classes of objects that haven’t been discovered yet as it will allow us to tell the difference between stars and other things.
“We should also be able to trace the evolution of our galaxy from the Big Bang to today by looking for the very oldest stars in our galaxy and those that have come from other smaller galaxies that merged with our own in the past.”
Due to the accuracy needed to achieve such pin-sharp pictures, engineers as space company Astrium have had to develop new technology to ensure the spacecraft does not change shape in the extremes of space.
Gaia is to be flown into an area of space where the gravitational pull from the sun and the Earth are equal so it will stay in the same exact position.
The spacecraft itself has been built from a recently developed material called silicon carbide as it is light, strong and will protect the camera from the extremes of space.
They have also developed a special thrusters that will use minute jets of nitrogen gas to precisely control the Gaia in space and to keep it steady.
More than 400 engineers have spent the past three years carefully putting the spacecraft together, often training using virtual reality simulators to ensure they get the precision alignments needed to obtain such high resolution pictures.