The Galileo Energetic Particles Detector
Galileo EPD Handbook
Chapter 2. EPD Software
EPD SBAND Mission Software Requirements (continued)
Source: S. Jaskulek, various dates
CDS-Produced EPD Telemetry Record
Table 12. EPD Science Record Format vs. Format Number
|
Format Number |
Telem. Alloc., bps |
Accum. Period, cycles |
Rate Channels |
Chan. Map |
CMS PHA Events |
Hskpg/ Status, bits |
Telem. Out, bps |
| 1,2,3,4,5 | 5 | 6 | 356 | 1 | 12 | 40 | 5.08 |
| 6,8 | 10 | 3 | 356 | 1 | 12 | 40 | 10.16 |
| 7 | 15 | 2 | 451 | 1 | 12 | 40 | 15.24 |
| 9,10 | 20 | 2 | 451 | 2 | 24 | 40 | 20.03 |
| 11 | 30 | 1 | 356 | 1 | 12 | 40 | 30.48 |
| 12 | 40 | 1 | 451 | 2 | 24 | 40 | 40.07 |
| Packet Type | Data Size | Description |
| Packet 1 | Rate Bin Data | |
| Map1 | 401 bytes | |
| Map2 | 508 " | |
| Packet 2 | CMS PHA and Housekeeping/Status Data | |
| Map1 | 35 bytes | |
| Map2 | 65 " |
RECORD/PLAYBACK SCIENCE PACKET HEADER
Figure 1. EPD2 Record Mode Packet Header
| Field Name | Data Offset | Field Size | Content/Description |
| Time Include Flag | 0 | 1 | =1, 1st packet and every 16th thereafter |
| APID | 1 | 7 | =0A hex |
| Packet Size | 8 | 9 | =76, 152, or 228 |
| Packet Sequence # | 17 | 7 | 0=127 |
| Packet Time | 24 | 32/0 * | R-R-R-mf |
| EPD Minor Frame Data | 56/24 * | 608 | 76-byte EPD Record Packet |
| EPD Minor Frame Data | 664/632 * | 608 | 76-byte EPD Record Packet |
| EPD Minor Frame Data | 1272/1240 * | 608 | 76-byte EPD Record Packet |
* The first number is for time included, the second is for time not included.
Time Included - This bit indicates if the time filed contains information. For the Record Mode data, time is included in the first packet of a new rate and every 16th packet thereafter. For those packets without the time, the packet is shortened by 32 bits.
Application ID - This 7-bit field generated by the CDS for all packets, and is used to identify the source of the data.
Size - This 9-bit field indicates the number of data bytes included in the packet.
Sequential Number - This 7-bit counter is incremented for each new EPD packet created.
Time - This 32-bit value will contain time reference data whenever the "Time Incl." flag is set. The format is "R-R-R-mf." This is the 24 least significant bits of the S/C RIM counter + spacecraft minor frame clock.
EPD2 REAL-TIME SCIENCE PACKET
Figure 2. EPD1 RT Mode Packet Header
| Field Name | Data Offset | Field Size | Content/Description |
| Time Include Flag | 0 | 1 | =1, Always |
| APID | 1 | 7 | =31 hex |
| Packet Size | 8 | 9 | =401 Map 1, Rate Packet =508 Map 2, Rate Packet =35 Map 1, PHA/Hskg Packet =65 Map 2, PHA/Hskg Packet |
| Packet Sequence # | 17 | 7 | 0-127 |
| Format ID | 24 | 4 | 1:5 bps 2:10 pbs 3:15 bps 4:20 bps 5:30 bps 6:40 bps |
| Packet Time | 28 | 28 | 1/2 R-R-R-mf |
| EPD RT Data | 56 | Rate or PHA/Housekeeping Data |
Time Included - This bit indicates if the time filed contains information. For the RT Mode data, time is included in every packet.
Application ID - This 7-bit field generated by the CDS for all packets, and is used to identify the source of the data.
Size - This 9-bit field indicates the number of data bytes included in the packet.
Sequential Number - This 7-bit counter is incremented for each new EPD packet created.
Telemetry Format - This 4-bit field indicates which CDS-EPD data collection mode was used to generate the record.
| 1: 5 bps | 2: 10 bps |
| 3: 15 bps | 4: 20 bps |
| 5: 30 bps | 6: 40 bps |
Time - This 28-bit value will contain time reference data whenever the "Time Incl." flag is set. The format is "1/2 R-R-R-mf." This is a translation of the 28 LSBs of the spacecraft minor frame clock.
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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.