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question about terms used with Pioneer 6
ncc1701d
post Mar 6 2019, 02:40 AM
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Hello,
I have been doing some research on Pioneer 6. I needed to convert a 2- 36 bit word double precision octal sequence into the number of seconds past 1950. The image Iam uploaded provide examples of what the answers should be after conversion to date. My main question is, does anyone know what MSP and LSP stand for? I was thinking maybe MSP and LSP was some well known JPL abreviation for something.
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mcaplinger
post Mar 6 2019, 03:07 AM
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QUOTE (ncc1701d @ Mar 5 2019, 06:40 PM) *
does anyone know what MSP and LSP stand for?

Most significant/least significant part.

Floating point double precision is a clue. Pioneer 6 was run by NASA Ames, I'm not sure what computer types they were using (this was long before IEEE floating point standardization.)


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ncc1701d
post Mar 6 2019, 03:59 AM
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QUOTE (mcaplinger @ Mar 6 2019, 03:07 AM) *
Most significant/least significant part.

Floating point double precision is a clue. Pioneer 6 was run by NASA Ames, I'm not sure what computer types they were using (this was long before IEEE floating point standardization.)
Great! thanks. Thats what I was looking for.
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nprev
post Mar 6 2019, 04:06 AM
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Admin note: Topic moved to Chit Chat from Mars section.


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AJAW
post Mar 10 2019, 06:34 PM
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I think the first three octal digits are the exponent (power of two) with an offset applied (which I'm too lazy to work out) followed by the mantissa. The examples do not seem to be the exact number of days I was initially expecting; the bit patterns seem to match the number of seconds part-way through the specified days. They do not seem to be an exact number of seconds, either, so presumably this format recorded higher-precision times than mere seconds.
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