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The Galileo Energetic Particles Detector


Galileo EPD Handbook


Chapter 1. Instrument Summary


CMS Analog Electronics (Post-Challenger Information)


Source: The Galileo Energetic Particles Detector, D. J. Williams et al., Space Science Reviews, 60, 385, 1992 (excerpts)


Figure 1-16 shows a block diagram of the CMS analog electronics. The velocity measurement is made via the Time-to-Amplitude Conversion (TAC) electronics, which measure ion velocity by converting microchannel plate-produced start and stop charge pulses into a bipolar linear signal whose amplitude is proportional to the time-of-flight of the ions over a known distance. The analog signal shaping times are similar to those used on the other CMS channels.


Figure 1-16. CMS analog signal processing block diagram.


Figure 1-17. CMS, new design. Source: Critical Design Review, Dec., 1987.


Pulse Height Analyzer (PHA) - Changes to Existing Circuit Boards


Source: Critical Design Review, Dec. 1987


  • Functional Description of Changes
    1. Latch added for channel select line (J select)
    2. PHA "event active" signal definition changed
    3. Amplifier gains tailored
  • Component Packaging: Minor Changes
  • Parts Questions: None
  • Functional Testing Results: No Problems
  • Known Outstanding Design Issues: None
  • Scope: Add 1 component; add 12 lines, remove 2


EPD PHA modifications block diagram




Continue: T.A.C. Board 


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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.