Geometry considerations for the JUICE Langmuir probes
Project work (30 c)
Student: Pedro Cervantes Correa, Luleå Technical University
Supervisor: Anders Eriksson
Period: Spring/Autumn 2013
ESA, the European Space Agency, has decided to fly the JUICE (JUpiter ICy moons Explorer) mission, with planned launch in 2022 and operations at Jupiter in 2030-2033. Among the instruments selected to fly is the Radio and Plasma Waves Investigation (RPWI), which includes Langmuir probes (LPs) mounted on booms protruding from the spacecraft. The LPs are versatile sensors, which can be used as electric antennas as well as for measurment of the space plasma. To make the most of the LPs, they should be mounted so as to avoid perturbations from the wake and the photoelectron cloud inevitably forming around the spacecraft. Exactly how these perturbations will be at a given instance in time depends on the details of the spacecraft trajectory and pointing as well as on the local plasma conditions, none of which can be predicted in detail. However, it is possible to draw general conclusions on the LP positions with respect to wake and photoelectron cloud from the planned JUICE trajectory in the Jovian system, combined with simplified models of photoemission and plasma behaviour.
Use the nominal JUICE trajectory for 2030-2033 combined with very simple generic geometric models of the spacecraft (whose design is not yet known), wake behaviour (based on plasma co-rotation with Jupiter and/or the moons we will fly by), and photoelectron cloud (based on simple assumptions) to study the possibilities offered by some tentative mountings of the LPs on the spacecraft.
ESA’s JUICE spacecraft at Ganymede. [Image credit: ESA/NASA]