CASSINI In Space

 

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GALILEO

The Galileo Energetic Particles Detector

 

Galileo EPD Handbook

 

Chapter 1. Instrument Summary

 

Galileo EPD Command Density at Satellite Encounter

Source: R. C. Moore, March 6, 1979

 

Ed Nipper, the JPL EEIS uplink coordinator, has requested that the EPD command density be estimated for satellite encounter situations.  The primary concerns are:

 

  1. How many different ground data command types are liable to be used at encounter, and
  2. How frequently will ground data commands have to be sent to the EPD at encounter.

 

Because much of the EPD operation is controlled by the internal microprocessors, the command density should be very low at all times, even at satellite encounters. We estimate that our maximum rate for ground data commands shall not exceed one data command per minute.

 

The following list shows the various data commands which might be sent during satellite encounter:

 

MNEMONIC OP-CODE DESCRIPTION
EPD RESCAN 01 Resume scanning
EPD ASCANB 16 Enter accelerated scan mode
EPD ASCANF 17 Exit accelerated scan mode
EPD LEMSOF 80 Turn off LEMMS
EPD CMSOFF 91 Turn off CMS
EPD LEMSON A0 Turn on LEMMS
EPD CMSONN B1 Turn on CMS
EPD GOTOS0 18 Go to sector 0
EPD GOTOS1 19 Go to sector 1
EPD GOTOS2 1A Go to sector 2
EPD GOTOS3 1B Go to sector 3
EPD GOTOS4 1C Go to sector 4
EPD GOTOS5 1D Go to sector 5
EPD GOTOS6 1E Go to sector 6
EPD GOTOS7 1F Go to sector 7
EPD ENAALT C4 Enable CMS alternate J/J'mode
EPD DISALT C5 DIsable CMS alternate J/J'mode
EPD TLMFM1 D0 Select EPD TLM format #1

 

The EPD requires no periodic data commands.

 

 

Next: Servicing the Galileo EPD Rate Channel Accumulators 

 

Return to Galileo EPD Handbook Table of Contents Page.

Return to main Galileo Table of Contents Page.
Return to Fundamental Technologies Home Page.

 

Updated 8/23/19, Cameron Crane

QUICK FACTS

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.