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The Galileo Energetic Particles Detector


Galileo EPD Handbook


Chapter 1. Instrument Summary


Charged Particle Response of Magnetic Deflection System for Galileo Jupiter Orbiter (draft) (continued)




The detection of energetic particles in a planetary environment is of importance both in space science experiments [1] and in theoretical calculation [2]. Galileo's Energetic Particles Detector (EPD) is designed to measure the composition, intensity, energy, and angular distribution of charged particles over the entire expected Jovian orbiter altitude range, 6RJ ≤ R ≤ 225 RJ (nominal orbit has 14 RJ periapsis). A comparison of Voyager 1 and 2 data strongly suggests that the relative contribution of Jovian and solar sources varies considerably with time. Thus, obtaining a long history of the Jovian energetic particle population is crucial to beginning a study of the dynamics of the Jovian magnetosphere [3].


The EPD uses two silicon solid-state detector systems: the low energy magnetic measurement system (LEMMS) and the composition measurement subsystem (CMS). The LEMMS sensor is designed to provide excellent energy and angular resolution down to energy thresholds of about 15 keV (electrons) and 20 keV (protons or ions) [4] and to clearly separate ions and electrons over the entire energy range. A substantial fraction of the particle population with this energy range is considered responsible for magnetic storms and accompanying magnetic turbulence in the Jovian environment. The particle population also plays vital roles in plasma instabilities, and hot-cold plasma interactions, convective processes, field aligned beams, wave-particle interaction, energy transport, and outflow processes. Thus observations of these particles will allow at times definitive studies and new clues to the above phenomena [5,6].


The objective of this work is to study the instrumental response of LEMMS in order to assist in the interpretation of laboratory calibrations. An accurate simulation of LEMMS will allow us to infer geometrical characteristics of the response which are otherwise impractical to obtain. By determining these geometric factors of the detectors, one can compute the efficiency of the system for the expected flight environment.



Next: Galileo LEMMS Simulation 


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Updated 8/23/19, Cameron Crane


Manufacturer: The Galileo Spacecraft was manufactured by the Jet Propulsion Laboratory, Messerschmitt-Bölkow-Blohm, General Electric, and the Hughes Aircraft Company.

Mission Duration: Galileo was planned to have a mission duration of around 8 years, but was kept in operation for 13 years, 11 months, and 3 days, until it was destroyed in a controlled impact with Jupiter on September 21, 2003.

Destination: Galileo's destination was Jupiter and its moons, which it orbitted for 7 years, 9 months, and 13 days.