The Galileo Energetic Particles Detector
Galileo EPD Handbook
Chapter 1. Instrument Summary
Command Changes
Source: Stephen Jaskulek, October 2, 1987
- Command Redefinition - below; please scroll down
- New Commands
- Note: Also see EPD Commands (pre-Challenger information)
Command Redefinition
A number of present EPD command functions will be altered by the proposed design changes. Below is a list of these commands.
TABLE 11. PROPOSED CHANGES TO PRESENT EPD COMMAND FUNCTIONS
| Command Name | State | Hex Code | Location | New Name/Function |
| TOVR AN | ON | C2 | PSB 4, bit 1 | "PRIME ACTIVE"/ Prime An. (simult. mode) on |
| TOVR AN | OFF | C3 | PSB 4, bit 1 | "PRIME ACTIVE"/ Prime An. (simult. mode) off |
| TOVR RL | ON | AB | PSB 2, bit 7 | spare (TOF spectrum off ??) |
| TOVR RL | OFF | 8B | PSB 2, bit 7 | spare (TOF spectrum on ??) |
| TOF POWER | ON | B2 | PSB 2, bit 4 | TOF POWER/Still TOF Power (±6 Volt only) |
| TOF POWER | OFF | 92 | PSB 2, bit 4 | TOF POWER/Still TOF Power (±6 Volt only) |
| CMS L CHANNEL | ON | BA | PSB 4, BIT 4 | KT/Same function, but chan. now used for KT |
| CMS L CHANNEL | OFF | 9A | PSB 4, BIT 4 | KT/Same function, but chan. now used for KT |
| CMS JC CHANNEL | ON | B8 | PSB 4, BIT 5 | JB'/Same function, but chan. now used for Jb' |
| CMS JC CHANNEL | OFF | 98 | PSB 4, BIT 5 | JB'/Same function, but chan. now used for Jb' |
| CMS JB CHANNEL | ON | B7 | PSB 4, BIT 6 | KT0 SELECT/Selects low energy thrshld on KT0 |
| CMS JB CHANNEL | OFF | 97 | PSB 4, BIT 6 | KT0 SELECT/Selects high energy thrshld on KT0 |
| JA00 ENABLE | ON | BB | PSB 4, BIT 3 | HIGH VOLT. ENABLE/Switch ±15 Volt on to HV |
| JA00 ENABLE | OFF | 9B | PSB 4, BIT 3 | HIGH VOLT. ENABLE/Switch ±15 Volt off to HV |
A number of present EPD command functions will be altered by the proposed design changes, in addition to new commands. Below is a list of the command changes. Note that initially more than one symbol can have a given hex code. For example, the ground support computer will generate the command code "C2" if I send either the command "LCR" or "SM." Eventually, the old command symbols will be purged from the command table.
TABLE 12. PROPOSED CHANGES TO PRESENT EPD COMMAND DICTIONARY
| Hex Code | Old Symbol | New Symbol | New Field Description |
| C2 | LCR | SM | Simultaneous mode ON ("PRIME ACTIVE" on) |
| C3 | LC | SMR | Simultaneous mode OFF ("PRIME ACTIVE" on) |
| AB | TRL | TS | spare (TOF Spectrum off ??) |
| 8B | TRLR | TSR | spare (TOF Spectrum on ??) |
| BA | CL | CKT | CMS Analog Kt ON |
| 9A | CLR | CKTR | CMS Analog Kt OFF |
| B8 | CJC | CJB | CMS Analog Jc ON |
| 98 | CJCR | CJBR | CMS Analog Jc OFF |
| B7 | -- | KTL | KT00 ON (Selects low energy thrshld on KT0) |
| 97 | -- | KTLR | KT00 OFF (Selects high energy thrshld on KT0) |
| BB | -- | HV | HIGH VOLT. ENABLE (Switch ±15 volt on to HV) |
| 9B | -- | HVR | HIGH VOLT. DISABLE (Switch ±15 volt off to HV) |
| FA | -- | VIT | VITO ON |
| FB | -- | VITR | VITO OFF |
| FC | -- | HLIM | SET HIGH VOLTAGE LIMIT |
| FD | -- | HREF | SET HIGH VOLTAGE REFERENCE |
Continue: New Commands
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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.