On Mon 2007-01-15T08:53:19 -0700, Rob Seaman hath writ:
> Any comments on the practicality of space-rating such timepieces?
GPS uses rubidium cells, and Galileo will.
I've seen ruminations about flying a cesium resonator and an ion trap
on ISS with a goal of redefining the SI second by allowing a long term
calibration of the "continually probe-able on earth" ion against the
"it always falls down on earth" cesium.
> Also - what are the actual use cases requiring a common time scale,
> rather than establishing a separate Martian civil cesium standard and
> simply tracking the deltas?
Robert A. Nelson.
Look up his numerous presentations on a Mars version of GPS in CGSIC,
PTTI, etc., and more recently IAU in Prague
http://tycho.usno.navy.mil/IAU31/nelson.ppt
(Which, by the way, includes the calculation that deviation between
Mars coordinate time and Earth coordinate time is about 25 ms
peak to peak.)
--
Steve Allen <sla_at_ucolick.org> WGS-84 (GPS)
UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99858
University of California Voice: +1 831 459 3046 Lng -122.06014
Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m
Received on Mon Jan 15 2007 - 08:34:52 PST