Hi So it's a pretty good AT cut crystal without any compensation of heating. Not quite a cheap wrist watch, but not a BVA in a dewar flask either.
Bob On Sep 21, 2013, at 8:11 AM, Jim Lux <[email protected]> wrote: > from JPL > http://www.jpl.nasa.gov/news/news.php?release=2013-275 > > "Mission controllers postulate that there was an anomaly generated by the > spacecraft's software which left the vehicle's computers in a condition where > they are continuously rebooting themselves. If this is the case, the > computers would not continue to command the vehicle's thrusters to fire and > hold attitude. Lack of attitude hold makes attempts to reestablish > communications more difficult because the orientation of the spacecraft's > antennas is unknown. It also brings into question the vehicle's electrical > power status, as the spacecraft derives its power from a solar array that is > fixed, with its cells pointing in one direction." > > > If it gets cold enough (without power from solar cells, it won't generate > enough internal heat to keep warm), it will die. That's probably what > happened to Spirit on Mars. It got cold enough during the Martian winter, > and with not enough solar power, enough things drifted cold enough that we > couldn't get commands in. > > > > BTW, DI uses star trackers for attitude knowledge, so it has the potential to > point very precisely. > > > If anyone is interested in the gory details of how the telecom system works > http://descanso.jpl.nasa.gov/DPSummary/di_article_cmp20050922.pdf > > Page 20 shows the variation in AuxOsc frequency of the SDST radio vs > temperature. That shape will look pretty familiar to list members. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
