UK to Take Leading Role in Exploring the Sun
On 14 March, scientists meeting at the Royal Astronomical Society in London will hear from Professor Richard Harrison of the Rutherford Appleton Laboratory and Dr Louise Harra of the Mullard Space Science Laboratory, University College London, how three spacecraft carrying novel telescopes and technology from the UK will be launched in 2005 as part of an international programme to explore our star, the Sun, and its influence on our lives.
These spacecraft will provide dramatic new advances in understanding our star, including:- The first views of the Sun in 3D - the first time that this has been done for any star;- The first views of solar-ejected clouds impacting the Earth;- Ultra-high resolution views of the solar surface and the Sun's atmosphere.
The spacecraft will travel to widely separated locations in the solar system to view the Sun from 3 completely different vantage points.
Richard Harrison will speak about a pair of spacecraft, known as the NASA STEREO mission. They will fly ahead of and behind the Earth, looking back at the Sun and Earth and while travelling away at about 30 million km per year. Their prime mission is to detect huge clouds erupting from the Sun and to track them to the Earth. These clouds can disrupt power distribution, navigation and communication systems, and satellite control systems and it is becoming increasingly important to understand and predict their arrival at Earth. Each event may carry one thousand million tonnes of gas into space from the solar atmosphere at speeds of anything up to 2000 km/s.
STEREO includes an array of telescopes, all of which use UK detector systems as well as a unique wide angle telescope system, known as the Heliospheric Imager, which will actually view the impact of the solar clouds on Earth. The Heliospheric Imager is being developed by a consortium led by the Rutherford Appleton Laboratory (RAL) in Oxfordshire and the University of Birmingham. The same two groups are developing the detector systems for the other US-led telescopes aboard STEREO.
'This will be the first time that a spacecraft has ever actually viewed the arrival of solar generated clouds at the Earth', says Richard Harrison, who is the Heliospheric Imager principal scientist, 'and it is particularly exciting that it is a UK instrument that will make this observation first.'
The technical innovation for the Imager and the detector systems comes from a long heritage of space missions and is managed by Dr Chris Eyles of Birmingham University, and Dr Nick Waltham of RAL.
'The idea of using two spacecraft is a novel one, allowing two vantage points to determine the 3-D nature of the Sun and of the clouds it ejects into space' says Dr Eyles,' and the fact that this is a NASA mission in which every imaging instrument uses UK detectors underlines the quality of the UK technical skills in this area.'
Solar physicists will be able to zoom in on the triggers of the explosions STEREO will observe with, with another spacecraft, Solar-B, which is the subject of Louise Harra's talk. This is a Japanese led mission primarily designed to observe the Sun in ultra-high spatial resolution from Earth orbit. One of the instruments aboard Solar-B is the UK-led Extreme Ultraviolet Imaging Spectrometer (EIS), which is being developed by a consortium led by the Mullard Space Science Laboratory (MSSL) of the University College London, and including Birmingham University and RAL. The principal scientist for EIS is Professor Len Culhane and Louise Harra is the project scientist.
'Solar-B is the next generation solar observatory, able to view the complex solar surface and atmosphere to a resolution of 175 km - which is the same as being able to pick out a cricket ball on a football pitch from space!' says Dr Harra, who is also a speaker at the RAS meeting on 14 March. 'The UK-led instrument is a spectrometer which measures the flows and dynamics of the solar atmosphere which can be used to understand the origin of the Sun's violent behaviour.'
1. The Royal Astronomical Society discussion meeting on Solar-Terrestrial Physics takes place on Friday 14 March 2003 in the lecture room at the Society of Antiquaries, Burlington House, Piccadilly, London W1 from 10.25 to 15.30. Dr Louise Harra's talk is scheduled for 11.20 and Prof. Richard Harrison's at 11.50.
More details about the meeting may be found at:
2. More information about Solar-B is available at
and about STEREO at
Date: 7 March 2003
Issued by Jacqueline Mitton, RAS Press Officer.