ESA is providing the first chairman for the International Living With A Star (ILWS) programme. ILWS is an unprecedented initiative in which space agencies worldwide are getting together to investigate how variations in the Sun affect the environment of Earth and the other planets, in the short and long term. In particular, ILWS will concentrate on those aspects of the Sun-Earth system that may affect mankind and society. It is a major collaborative initiative between Europe, the United States, Russia, Japan, and Canada.
The Sun is a variable star. The amount of radiation it releases changes constantly, especially at wavelengths that we cannot see, such as ultraviolet. It also releases a stormy ‘wind’ of particles known as the solar wind that buffets the Earth’s magnetic field. Sudden changes in the solar wind can disable communications satellites, disrupt power stations on Earth, and affect passengers in high-flying aircraft. Slow variation in the solar output and even in the solar wind could contribute to climatic changes. Knowing more about these phenomena is therefore very important in different and sometimes unexpected ways.
There will be various ILWS mission launches over an approximately ten-year period, starting in 2003. Pooling the resources of the largest fleet of spacecraft in history, the ILWS programme will provide a first global view of the Sun-Earth interaction and lead to a real understanding of it. It will look at the Sun’s effects on other planets also.
ESA’s missions form a vital part of ILWS. SOHO and Cluster are leading the way. In 2003, in collaboration with China, a space mission called Double Star will be launched to complement Cluster. In a decade’s time, ESA’s Solar Orbiter will be the centre of interest. It will go closer to the Sun than any solar mission ever before. In between, ESA will assist in exploiting other agency’s missions to the full; it is also currently negotiating to provide ground stations for Japan’s Solar-B mission (launch 2005), and is considering the part it may play in NASA’s STEREO (launch 2005) and Solar Dynamics Orbiter (launch 2007) missions.
In addition, ESA’s missions to the other terrestrial planets, Mars Express (launching 2003), Venus Express (launching 2005), and the mission to Mercury, BepiColombo (launching 2011/2012), will carry experiments that look at solar-wind interactions with their respective planets.
Hermann Opgenoorth, ESA’s newly appointed Head of Solar and Solar-Terrestrial Missions, is chairing the ILWS steering committee for the first two years. “There is a clear need to study the Sun and its interaction with the Earth” he says, ” and it is too big a job for a single space agency to cope with.”