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Digitizing NASA-ESA Taped Imagery, project to digitize 60s-70s data
apollo16uvc
post Feb 28 2019, 10:11 PM
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Hello dear readers,

Here are some satellite telemetry tapes I have acquired. They are from the 60's to 70's.





These tapes contain the raw signal received from satellites at NASA tracking stations like GFORKS, STIAGO and WINKFIELD.

It seems that there 2 telemetry tracks, 4 misc tracks (Including a reference track) and one voice track.

I am working on getting a recorder to play these tapes. If you know the location of any 7-track instrumentation recorders (Ampex FR-100, FR-600) that would help.

Here is a sample of tape 3141/2N003 played back on a 1/4 inch 4-track Akai at 7.5 I.P.S: https://www.dropbox.com/s/k2jbyoka6n50yhh/3...168-2.flac?dl=0
The tape number on the boxes and documentation is 3141/2N003. The number on the reel itself is 10786-16-8.

Satellite: 1963-014A & B (ERS5)
Recorder: FR-100
Speed: 15 I.P.S
Station Name: GFORKS

Here is an other sample from a different tape: https://forum.nasaspaceflight.com/index.php...1683;sess=54302

Here is a video showing the tracks: https://youtu.be/I85-aZuupxM
With this we have proven that something is on the tape, and it can be picked up with a sound head. This is the case with most of my tapes.

I am currently talking with someone who has several 1/2 8-track studio tape recorders, and we are looking into getting an Otari MX-5050 8 unit working. This unit is most useful because it can play at both 7.5 I.P.S and 15 I.P.S, which is what we need. All mechanical functions seem to work fine, and the input VU meters register when the build-in tone generator is switched on. But... there is no sound from his tape! (His own audio, not a NASA tape)

This recorder is currently undergoing repairs.

Other tapes I have acquired are ESA tapes from the same era.
I have tested out three of the five ESA tapes with a magnetic viewing solution, and all three clearly showed 7 tracks like the NASA tapes. This means they have not been degaused or overwritten with an audio recorder. The tracks look like raw telemetry, not computer tapes. One tape has a label that clearly says it came from a tracking station. I think we should be able to digitize these too eventually. The tracks are very clear.

The tapes I have tested are:
TD-1 (Tape ID: 1117-09-08- cool.gif
ESRO 1A (Tape ID: 800 645 08 10B)
HEOS A2 (Tape ID: 1115 06 11B)

I have made two videos on it in dutch.
First, a tutorial on how to make your town magnetic viewing solution.
https://www.youtube.com/watch?v=j_kA0cnkBLI


And finally, a video where I visualize the magnetic tracks on 3 tapes:
https://www.youtube.com/watch?v=LAjU2AHIksA

I have attached some photos of the tracks to this message. I promise I will publish a big archive with detailed scans and photos of all ESA and NASA tapes currently in my possession.

Macro photos (Large!)
https://imgur.com/a/rnlJH9P


So what are we looking for?
I am interested to know if its possible to determine the frequency of a track with the track photos.Is it possible to replace the 8-track head in an 1/2 inch Otari tape recorder with a 7-track head, perhaps from a computer tape drive?Is it possible to decode the digitized raw telemetry data into numbers, perhaps a spreadsheet or interactive database?Would people be interested to crowdfund some of the greater expenses that may be required?
Best regards,Niels
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Gerald
post Mar 21 2019, 11:56 PM
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Thanks for constraining this further down!
A 100101, for example, in NRZL can be interpreted as a 01 in differential Manchester BP-M, with the initial 10 in (10)0101 as clock signal, the 00 in 1(00)101 encoding a 0, then 01 in 10(01)01 the next clock signal, 10 in 100(10)1 encoding a 1, then 01 1001(01) clock, and so forth. In BP-S, the same NRZL sequence would encode 10, if read from left to right.
So, you can just digitize the NRZL, and decide later, how to translate it into a Manchester bit stream of various possible types. If the tape is recording a sequential bit stream, it's possible that the direction of the recording is alternating with the tracks, meaning that, in principle, only one head is necessary to write and read the track. After reading the first track, the head is moved to the next track, and the tape is running backward. That's to be considered for decoding.

The next step would then look for a header or preamble in the recording, in order to see, whether it's defining some type of higher-level convention. But I'm not sure, which standards have been defined back in 1963.
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apollo16uvc
post May 7 2019, 07:43 PM
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QUOTE (Gerald @ Mar 22 2019, 12:56 AM) *
Thanks for constraining this further down!
A 100101, for example, in NRZL can be interpreted as a 01 in differential Manchester BP-M, with the initial 10 in (10)0101 as clock signal, the 00 in 1(00)101 encoding a 0, then 01 in 10(01)01 the next clock signal, 10 in 100(10)1 encoding a 1, then 01 1001(01) clock, and so forth. In BP-S, the same NRZL sequence would encode 10, if read from left to right.
So, you can just digitize the NRZL, and decide later, how to translate it into a Manchester bit stream of various possible types. If the tape is recording a sequential bit stream, it's possible that the direction of the recording is alternating with the tracks, meaning that, in principle, only one head is necessary to write and read the track. After reading the first track, the head is moved to the next track, and the tape is running backward. That's to be considered for decoding.

The next step would then look for a header or preamble in the recording, in order to see, whether it's defining some type of higher-level convention. But I'm not sure, which standards have been defined back in 1963.


Due to these being telemetry recordings made on instrumentational recorders, its likely they are compliant with the IRIG standard.

See the following IRIG timecodes: https://en.wikipedia.org/wiki/IRIG_timecode

Modulation type
  1. (DCLS) Direct Current Level Shift (width coded)
  2. Sine wave carrier (amplitude modulated)
  3. Manchester modulated
Carrier frequency
  1. No carrier (DCLS)
  2. 100 Hz (10 ms resolution)
  3. 1 kHz (1 ms resolution)
  4. 10 kHz (100 Ás resolution)
  5. 100 kHz (10 Ás resolution)
  6. 1 MHz (1 Ás resolution)
The signal received on TD-A1-3 is 5Khz or 10Khz depending on the playback speed. I hope I can achieve the required recording resolution.


Some useful links:
http://irig.org/

http://www.irig106.org/
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