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The Galileo Energetic Particles Detector


Galileo EPD Handbook




Appendix E. EPD File Structure (continued)


2. Record Header

Source: T. P. Armstrong, March 30, 1985


Galileo EPD Record Header Definition


This header block will be present in all EPD records.


Item Description Type Length
0 Spacecraft Name
  Value Meaning
  'ISPM' International Solar Polar
  'GALI' Galileo
A*4 4
1 Record Descriptor
  Value Meaning
  'EPDH' File Header Record
  'HHSS' Housekeeping and Status Record
  'LMPA' LEMMS Pulse Height Analysis Record
  'PHAR' Pulse Height Archive
  'RATE' Rate Block
A*4 4
2 Production Date
"DD-MMM-YY" Creation Date
A*10 10
3 File Type
  "AV"=EPD Average
  "AR"=EPD Archive
A*2 2
4 Procedure Name A*6 6
5 Procedure Version I*2 2
6 Time of First Data Occurrence
  Array # Description
 1 Year
 2 Day
 3 Hour
 4 Minute
 5 Second
I*2 10
7 Time of Last Data Occurrence
(see expl. of item #6)
I*2 10
8 Instrument Status Block (report of voltages, temperatures, and digital status flags) I*4 TBD
9 Magnetic Field Data
  Coordinates: Payload
  Variable: BDATA(64,4)
  First Index: Labels up to 64 repetitions of magnetic field data in each record. This is included to give maximum time resolution in subsequent pitch and phase angle calculations as per the request of DJW 4/24/84.

  Second Index:

# samples
R*4 6
10 Ephemeris Block

Heliocentric Inertial Cartesian States (x, y, z, vx, vy, vz--km & km/sec) of:
   a.) Spacecraft
   b.) Earth
   c.) Jupiter

Jovicentric Mean Orbit Cartesian States (x, y, z, vx, vy, vz--km & km/sec) of:
   d.) Spacecraft
   e.) Io
   f.) Europa
   g.) Ganymede
   h.) Callisto

Jovicentric Magnetic Axis System III Spherical Coordinates (r, theta, phi) of:
   i.) Spacecraft
   j.) Io
   k.) Europa
   l.) Ganymede
   m.) Callisto

11 Orientation Block
 Transformations from:
   a.) Payload to SCC. (SCC--spacecraft centered corotation)
   b.) Payload to Heliocentric
   c.) Payload to System III
   d.) Payload to Inertial
   e.) Payload to B field
12 Sector Block

 THETA(60,8,2) Polar angle of 60 sectors in 8 steps
 for B field coords. (1) and SCC (2)
 PHI(60,8,2) Azimuth angle of 60 sectors in 8 steps
 for B field coords. (1) and SCC (2)
 BMAG(60,8) Magnitude of B field for 60 sectors and 8 steps

13 Stepping Block
    Variable: ISTEP(12)
     Type: I*4
     Index Contents
1 Step position for this record (0-7)
2 Step position for former record (0-7)
3 Next expected step position (0-7)
4 Position expected in next record (0-7)
5 Direction of step movement:
   +1 = increasing
   0 = this record is from a turn
   -1 = decreasing
6 Minimum sector of scan (0-7)
7 Maximum sector of scan (0-7)
8 Dwell time (milliseconds) per step
9 Slew rate (millidegrees/second)
10 Spare
11 Spare
12 Spare
14 Spares -- TBD
15 Number of Physical Records in this Logical Record I*2 2
16 Index of this Physical Record

Explanation of items 15 and 16:  For record types of length small enough to fit into the fixed (defined) number of bytes for an EPD record, the blocking factor will be 1:1. That is, item #14 = 1 and item #15 = 1. For large logical records which would necessarily span several physical records, item #14 gives the blocking factor, say 8 for 8:1, and item #15 tells which of the 8 possible records this one is.

I*2 2



Next: 3. Rate Block 


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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.