Voyager LECP

VOYAGER

Voyager LECP Data Analysis Handbook

Data File Descriptions

Master Rate (Tape) File Descriptions

Voyager LECP Master Rate Tape Format for CR-5A/UV-5A

Figure B-1

Physical Tape Organization for CR-5A

MRT Record 1

MRT Record 2

MRT Record n

ENG Record 1

MRT Record n+1

ENG Record m

EOF

Figure B-2

MRT Record Structure for CR-5A

MRT Header
38 16-bit words
1 -- 39

MRT Data
366 words
39 -- 405

MPT Data
80 words
405 -- 485

MRT Data Expanded

R3(3,32)
96 Real*4
192 16-bit words
39 -- 231

R1(26)
26 Real*4
52 words
231 -- 283

QR3(3,32)

96 words
283 -- 379

QR1(26)

26 words
379 -- 405

Table B-1

MRT Record Contents for CR-5A

Words	Contents
1-38	MRT Header, defined by Table B-2 (below).
39-282	RS(122) Real*4 rates, consisting of R3(3,32) and R1(26). Individual logics are defined in Table B-3.
283-404	QRS(122) Integer*2 quality words for rates above, consisting of QR3(3,32) and QR1(26). Quality words are defined in Table B-4.
405-484	PA(5,32) Logical*1, 32PHA data points of 5 bytes each, Table B-5.

Table B-2

MRT Record Header (CR5A)
(Compare to MRT original.)

Integer	Byte	Variable	Description
1	1	MRID	SCID Spacecraft ID 1=Voyager 1 0=Voyager 2
1	2	MRMOD	SCDMSpacecraft telemetry mode 1-6 Cruise 2-7 7 Cruise 1 8 Near Encounter 10 (OAH) Far Encounter 24 (18H) Cruise 5A 19 (1DH) UV-5A
			Spacecraft Event Time - contains the Greenwich Mean Time (GMT) of the first PN bit of the first minor frame (MF) used in this LECP major frame.
2	3-4	MRETH	SCETH Spacecraft Event Time, Hour - Binary hours since the beginning of the current year.
3	5-6	MRETS	SCETS Spacecraft Event Time, Seconds- Binary seconds since the beginning of the current hour.
4	7-8	MRETMS	SCETMS Spacecraft Event Time, Binary - Binary milliseconds.
5	9-10	MRETYR	SCETYR Spacecraft Event Time, Year- Two least significant digits of year, e.g. 78
6	11	MRFLAG	SCEF*16+FDSCFF where SCEF is Spacecraft Event Time Flag 0000 input by NORT file 1111 input by EDRPROC FDSCFF is FDSC Correction Flag which indicates that the FDSC has been corrected. (1=corrected, 0=OK) Bit 3 Spare Bit 2 MOD216 Bit 1 MOD60 Bit 0 Line Count
6	12	MRG181	Group 18 ID
7	13-14	MRM216	Mod2**16 counter from the Flight Data System (FDS). Increments each 48 minutes.
8	15-16	MRM60	Mod60 counter from the FDS. Increments each 48 seconds
9	17-18	MRLINE	Line counter from the FDS. Increment every 60 ms.
10	19-20	MRS1	S1 LECP Status Word 1, MSB=1 if missing.
11	21-22	MRS2	S2 LECP Status Word 2, MSB=1 if missing
12	23-24	MRS3	S3 LECP Status Word 3, MSB=1 if missing
13	25-26	MRS4	S4 LECP Status Word 4, MSB=1 if missing
14	27-28	MRS5	S5 LECP Status Word 5, MSB=1 if missing
15	29-30	MRS6	S6 LECP Status Word 6, MSB=1 if missing
16	31-32	MRMOT	LECP Motor Position - contains the motor position at the end of the current record. = 1 if unknown, otherwise Bits 3-1 Motor position (0-7) for sector (1-8) Bit 0 Centered flag, =1 if centered.
17	33-34	MRNMOV	Number of motor steps. Turn arounds in sectors 8 and 1 or 2 are considered to be 2 steps. = -1 if unknown.
18	35-36	MRLOGT	Log. Amp. Temperature in Deg C*128. =-9999 if unknown
20	39-40	MRMSI	Basic accumulation interval in .01 sec.
21	41-42	MRQ	Quality of frame = number of good groups
22	43-44	MRRT	Record type 1 MRT 2 MPT Header 4 SEDR 10 Eng 11 Cal
23	45-46	MRVER	Version number of S1P program used to process this data.
24	47-48	MRALT	LEPT/LEMPA - In GS-3 alternating mode this word indicates which logics are being read out in the current record: -1 = unknown 0 LEPT 1 LEMPA
25	49-50	MRRAB	Redundancy A/B - indicates which of the LECP redundant data systems is being used. -1 unknown 0 A 1 B
26	51-52	MRPRO	Processing status 0 S1P 1 S2P, motor corrections applied
27	53-54	MRMOR	Motor period in seconds with some special cases: -1 Not known 0 Not decoded 9000 Encounter Stow (Vgr 2 Jupiter enc) 10000 Stowed or commanded to position Values implemented in software include 5, 6, 24, 48, 144, 192, 360 (6 min), 384
28-36	55-72	MRS5S	Nine S5's for Near Encounter only
37-38	73-76		Spare

Appendix B continued:

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Updated 8/9/19, Cameron Crane

VOYAGER 1 ELAPSED TIME

--:--:--:--

Days: Hours: Minutes: Seconds

*Since official launch
September 5, 1977, 12:56:00:00 UTC

VOYAGER 2 ELAPSED TIME

--:--:--:--

Days: Hours: Minutes: Seconds

*Since official launch
August 20, 1977, 14:29:00:00 UTC

QUICK FACTS

Manufacturer: Voyagers 1 and 2 were built in the Jet Propulsion Laboratory in Southern California.

Mission Duration: 40+ years have elapsed for both Voyager 1 and Voyager 2 (both are ongoing).

Destination: Their original destinations were Saturn and Jupiter. Their current destination is interstellar space.