[ntp:questions] (reissue, typo) Voyager I & II (31 & 32 NASA-launch numbers) internal timekeeping format

Max Power mikehack at u.washington.edu
Sat May 27 07:21:23 UTC 2006


Internal specs I would like to see: Voyager I & II (31 & 32 NASA-launch 
numbers) internal timekeeping format.

The time & date keeping format is important because sequence and 
sub-sequence (timers) depend on the system clock.

The acquisition of RGB colour images at Jupiter, Saturn and Uranus via using 
sub-sequences to optimize orthicon image stability via slowly moving the 
scan platform. That spacecraft hack had a very heavy system clock 
dependency, as the scan platforms had to be slewed very very slowly.

I suspect that Voyager craft ignore the century, as the MSF timecode does.

The atomic clocks and system clocks on these craft are still highly 
accurate, but the clocks are only updated at best once per year due to the 
(24 hrs +) one way delay. The craft's system clock is accurate to within 1.0 
{sec}, still as good as any poorly maintained NTP server.

== Assumptions ==
I assume the date & time system is obviously some BCD data structure of some 
kind.

Earth Time (UT) and Spacecraft Time (LT) need to be tracked precisely for 
navigation -- as well as running mission sequences like recording data and 
calibration.

I assume the date system was made Y2K proof long before Y2K came along, and 
is possibly Y2038 proof.
The craft will all expire long before 2038 (probably around 2025). 





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