The general objective of ASPERA-4: Analyser of Space Plasmas and Energetic
Publication date: 02 November 2007
Authors: Barabash, S., et al.
Journal: ESA Special Publication
Copyright: ESAThe general objective of ASPERA-4 (Analyser of Space Plasmas and Energetic Atoms) is to study the solar wind-atmosphere interaction and characterise the plasma and neutral gas environment in near-Venus space through energetic neutral atom (ENA) imaging and local charged particle measurements. The studies address the fundamental question: how strongly do the interplanetary plasma and electromagnetic fields affect the atmosphere of Venus? ASPERA-4 comprises four sensors: two ENA sensors, and electron and ion spectrometers. The Neutral Particle Imager (NPI) measures the integral ENA flux (0.1-60 keV) with no mass or energy resolution but relatively high angular resolution. The Neutral Particle Detector (NPD) measures the ENA flux, resolving velocity (0.1-10 keV for hydrogen) and mass (H and O) with a coarse angular resolution. The electron spectrometer (ELS) is a standard top-hat electrostatic analyser (energy range 0.001-20 keV) in a very compact design. These three sensors are on a scanning platform providing 4p coverage. ASPERA-4 also contains an ion mass composition sensor, IMA (Ion Mass Analyser). Mechanically, IMA is a separate unit electrically connected to the ASPERA-4 main unit. IMA provides ion measurements in the energy range 0.01-36 keV/q for the main ion components H+, He++, He+, O++, O+ and CO+2 ion group with M/q > 40 amu/q.