On 13 June, the Proton-Alpha Sensor (PAS) arrived at the Mullard Space Science Laboratory (MSSL) in England. Once aboard the Solar Orbiter satellite, this instrument will measure solar wind density, temperature and speed, and more specifically the particle distribution: turbulence and wave/particle interactions. PAS will take 10 million measurements per second, 100 times more than any previous instrument.
Before being mounted on the satellite, PAS will be subjected to a battery of tests. These tests were designed by the French IRAP laboratory with significant CNES contributions. During the Solar Orbiter mission, the satellite will come as close as 0.28 au and as far as 1.2 au to the Sun, which will lead to very wide temperature variations. PAS’s heat shield will be subjected to temperatures ranging from -120 to +150°C and the instrument has to be maintained between -40 and +60°C. Several ambitious tests involving thermal vacuum, solar vacuum, high temperatures and high voltage displayed the instrument’s capabilities.
On 8th June, Airbus Defence & Space (ADS) received the Main Electronics Box (MEB) and the Search Coil Magnetometer (SCM) in Stevenage, England. Both components are sub-systems part of the Radio and Plasma Waves instrument (RPW).
RPW will measure the electric and magnetic field using the SCM, located on the satellite’s arm, and 3 antennae which should be delivered to ADS as early as September. They are currently being built by American company Stellar Scientific LLC, and the prototype antenna is being tested by CNES.
France contributes to 6 of the 10 scientific instruments aboard Solar Orbiter. The satellite is scheduled for launch in February 2019.