Analyser will study root causes of space weather disturbances

A team from UCL’s Mullard Space Science Laboratory is finalising the first prototype of the Solar Wind Analyser (SWA), which will fly on board the Solar Orbiter mission.

The European Space Agency (ESA) confirmed last week that the Orbiter will fly in 2017 as part of its Cosmic Vision programme.

SWA will study the root causes of space weather disturbances in a bid to provide advanced warning of major events. Specifically, it will analyse the electron, proton and alpha-particle populations that form the solar wind — which ultimately interacts with Earth’s magnetosphere.

As Prof Chris Owen of UCL explained to The Engineer, the practical challenges in doing so have been two-fold. The instrument to detect the highly scattered electrons has to be in the shadow of the spacecraft, while the instrument to detect heavy protons, which travel in a ‘bullet-like’ fashion, must be head-on to the Sun.

Due to these extremes in temperature, the team, which includes researchers in Italy, had to look at alternative materials and techniques.

Owen explained that the apertures for the proton detector, which control the entry of particles, have a ‘bespoke thermal shield’ to deflect heat. Meanwhile, the electron detector is equipped with a design incorporating insulation, as well as internal heating to prevent the temperature dropping too far. Nevertheless, as Owen explained, there may still be problems when the instrument is actually in flight.

‘The big problem is if you get a slight incorrect orientation of the whole spacecraft, you’ve got an instrument that is engineered to survive at -200ºC that might then suddenly shoot up to +100ºC or +200ºC,’ Owen said.

His team is currently readying the first prototype of the electron detector for initial testing in the next few weeks. It will be placed in a vacuum chamber and be bombarded with an artificial electron beam, replicating the solar wind, and cooled down close to the temperatures it will experience in space. A vibration table will subject it to the forces it will experience at launch.