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:
- How many different ground data command types are liable to be used at encounter, and
- 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
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Updated 8/23/19, Cameron Crane
QUICK FACTS
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.