ESA's cluster quartet ready for work
The European Space Agency's (ESA) cluster quartet of satellites are now flying in their final orbit around the Earth, ready to enter the scientific commission and operation phase of their mission. It can now join the SOHO spacecraft and begin the implementation of ESA's 'Horizons 2000' programme. 'Over the next four months, all scientific equipment onboard the spacecraft will be gradually brought to life. The same instrument on each spacecraft will be switched on one after another,' says ESA. These instruments will undergo a series of health and calibration checks over the next three months and by December all 44 instruments will be operational and able to start the scientific mission. ESA hopes the cluster quartet will be able to record the most detailed three-dimensional information yet on processes in near-Earth space and the interaction between the Sun and the Earth.