PSE Tape File Format

Record size: 19K (19,456 bytes), fixed-length format

Frame size: 72 bytes (old format), 36 bytes (new format)

New format: The new format is defined only for the A12 PSE data since Oct.16, 1971. The SPZ data are not contained in the new format data files, because SPZ sensor malfunctioned at the A12 site.

File constitution:
Each PSE file consists of about 520-530 records for the old-format data and 260-265 records for the new-format data,and each record consists of a 16-byte header plus 270 72-byte (old format) or 540 36-byte (new format) data frames. It corresponds to 3 (old format) or 6 (new format) physical records of the original PSE tape. (Each physical record of the original PSE tape contained 90 logical records (frames) of the data.)

Header Format

Bytes	Information (16-bit integers)
1-2	1 for PSE tapes; 2 for Event tapes
3-4	Apollo station number
5-6	original tape sequence number for PSE tapes; 2-digit station code plus 3-digit original event tape sequence number for Event tapes
7-8	record number
9-10	year
11-12	format (0=old,1=new)
13-14	number of physical records from original tape
15-16	original tape read error flags (lsb set if read error occurred while reading the first physical record from the original tape, etc)

Data Format

*1 Long word consists of 32 bits
*1 ALSEP word consist of 10 bits
Long Word	Bits	Data
1	0	software time flag (set at JSC for clock substitution)
1	1-31	31msb of 35-bit time of the year in ms
2	0-3	4lsb of 35-bit time of the year in ms
2	4-7	ALSEP tracking station ID
2	8-13	bit error rate (from original tape)
2	14	data rate (1=1060bps, 0=530bps)
2	15-21	not used
For Old Format
2	22-31	ALSEP word 5
3-18	0-9	ALSEP words 1,4,9,12,16,22,26,29,33,36,40,43,46,52,58,61
3-18	11-20	ALSEP words 2,6,10,13,18,24,27,30,34,37,41,44,48,54,59,62
3-18	22-31	ALSEP words 3,8,11,14,20,25,28,32,35,38,42,45,50,57,60,64
3-18	10,21	not used
For New Format
2	22-31	not used
3-8	0-9	ALSEP words 1,9,25,33,41,46
3-8	11-20	ALSEP words 2,11,27,35,43,57
3-8	22-31	ALSEP words 3,13,29,37,45,59
3-8	10,21	not used
9	0-9	ALSEP word 61
9	10-31	not used

ALSEP Word Allocation

Each ALSEP word consists of 10 bits of data, and usually contains one sample of scientific data. Please refer to ALSEP Word Allocation to know each ALSEP word contents.