The photograph shows the flight model of the Electrostatic Analyser System (EAS), which is part of the Solar Wind Analyser (SWA) Suite of instruments to be launched on the European Space Agency's Solar Orbiter mission. SWA is an international consortium providing 3 sensors and a joint data processing unit. UCL/MSSL is the lead institution (I am the Principal Investigator for the full suite). EAS in particular was designed, built and tested within the UCL/MSSL facilities and will be delivered to ESA for integration to the Solar Orbiter spacecraft at the end of this month. The spacecraft is being assembled at Airbus UK in Stevenage.

Solar Orbiter will travel in close to the Sun (inside the orbit of Mercury) and move to high solar latitudes in order to view the poles of the Sun. Data recorded during its (up to 10 year) mission will help answer scientific questions on how the Sun creates and controls the heliosphere. Launch will be in Feb 2019 or Feb 2020.

In the photograph you can see the 2 cylindrical analyser heads which together can scan the full sky to detect electrons of solar origin arriving at the spacecraft. These are mounted with axes at right angles to each other on the control electronics box, which can be seen covered in its black MLI (multi-layered insulation) jacket. Although the Solar Orbiter spacecraft will need to deal with the heat of the near-Sun environment, EAS will be mounted on a boom and always in the shadow of the spacecraft. The MLI thus protects the instrument from the effects of extreme cold associated with exposure to deep space.