Complex 39 STS OIS Channelization

Or: how to work out who is actually talking on one of my voice tapes

Back to the Space Shuttle documents page, or over to the V1202 Helium Signature Test page.

The OIS is the Operational Intercom System – the hardwired intercom that everybody working a test is plugged into. Headset, keyset, a bank of channel selects, talk and listen. If you were running a procedure you had a couple of loops up in one ear and the person standing next to you in the other, and you learned very quickly to keep them separate. Every one of my voice tapes is a recording off one of these channels.

Which means the channel number on the tape label is not trivia – it tells you which console you are listening to and therefore what the conversation is even about. A tape marked "Channel 132" is the Orbiter Test Conductor loop. A tape marked "Channel 168" is MPS. Same test, completely different conversations.

Reading the entries

Each line is channel number, function, and in parentheses the console callsign. The callsign is the part you need. Nobody on a loop says "this is the Main Propulsion System console", they say CMPS. Nobody says "Hazardous Gas Detection System", they say CHGD. The first letter 'C' indicates that they are in the firing room on console. If they prefix with a 'R', if they say 'RMPS' for example, then they are stating that they at the OPF or the pad, somewhere not on console. If you are trying to follow a tape, the parentheses column is the decoder ring and the function column is just there to tell you what the person does for a living.

Channels marked SEE NOTE are unassigned on the card. Per the form, the NTD assigns those for trouble-shooting or overflow – so if a test went sideways and got pushed to a side loop, it went to one of those, and there is no permanent record of which. That is a real gap and no document is going to close it.

TP – Test Directors and Test Conductors (Colloquially the project managers)

TV – Vehicle Systems Channels

This is where the actual engineering happens. If you want to know what a system was doing, this is the block you want.

TE – Ground Systems, Facilities and Support channels

CS/DOD – Payload Channels

Note channel 244. Trouble-shooting doubles as AFT 9. If a job went bad and got taken off the main loop, this is one of the places it went.

SI, MD, RO, RT

Acronyms

The channel card assumes you already know the vocabulary, because everybody carrying one did. If you don't, the other document to have open is the CLCS Acronyms and Abbreviations list, 84K00240 Rev B. Fifteen pages of nothing but acronyms, which tells you something about the place.

Read that one with a caveat. 84K00240 is dated November 1999 and it documents CLCS – the Checkout and Launch Control System, which was the programme to REPLACE the CCMS/LPS gear I actually worked on. Most of the vehicle vocabulary carried over unchanged (MPS is MPS, HGDS is HGDS, SSME is SSME) but a good chunk of that document is CLCS software architecture that never existed in my firing room. Useful reference, wrong decade for some of it. Don't cite it as period vocabulary without checking.

The ones you will actually hit on a propulsion tape:

Why any of this matters

The tapes are the only reason I built this page. A transcript that says "see em pee ess, oh tee see, go for pressurisation" is noise. The same line with the card in front of you is CMPS answering the OTC on 132 and it is now an operational record.

Machine transcription does NOT know any of this. It will turn CHGD into "charged" and CMPS into "compass" and scim into "skim", every single time, with total confidence. Every transcript I put up gets corrected by hand against this card, and where I am guessing I say so.

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