Mariner 4 Master Data Records - data conversion
Tapes K_0013 to K_0173
Data in hexadecimal format
- yellow - length of record
- white - line of data
- first two bytes of record consist of length of record in order L2L1( 2 x 8 bits used)
- 4E00 length value - 004E (in hex) - 78 bytes decimal
- 0000 length value - 0000 (in hex)- 0 bytes decimal (error on tape)
Dividing chain of bytes
- record 1 - 78 bytes
- record 2 - 78 bytes
- record 3 - 0 bytes (error on tape)
- record 4 - 78 bytes
Record conversion to chain of bits
- step 1 - conversion of bytes to stream of bits
- step 2 - removal first 2 bits in each byte (added in process conversion from 7-track tapes to 9-track tapes)
- step 3 - creating new stream of bits
Data identification in stream of bits
Type of data identification
- type 1 - Data Mode 3 (science data only)
- type 2 - Data Mode 2 (science data and engineering data in order: science - first, engineering - second)
- type 3 - Time Hacks
Dividing stream of bits in case Data Mode 2 and Data Mode 3
- 1 - 51 51 bits - unknown
- 52 - 316 265 bits - science data starting from 6 bit in word 2 to word 28 ( 15 bits PN is omitted)
- 317- 456 140 bits - engineering data or science data words 29 to 42
- 457- 468 12 bits - binary null
Data words
- science data - 10 bits per word
- engineering data - 7 bits per word
Last Updated: 2002.04.05
