[time-nuts] GRAIL USO (was: Looking for datasheet for Oscilloquartz 8602)

Attila Kinali attila at kinali.ch
Sat Jun 1 11:49:16 EDT 2013


On Tue, 28 May 2013 20:23:06 -0700
Jim Lux <jimlux at earthlink.net> wrote:

> The USO's we got for GRAIL from APL have ADEV<1E-13 from 1 to 1000 
> seconds, and then heads up at 1 decade/decade.  The lowest ADEV is about 
> 5E-14 at around 50 seconds, but it's pretty flat.  See the paper by 
> Enzer et al.

Do you mean [1]?

[1] "GRAIL ­ A Microwave Ranging Instrument To Map Out The Lunar Gravity Field",
by Enzer, Wang, Klipstein, 2010 


> Or better, the 42ns PTTI conference paper by Greg Weaver at APL, who had 
> to build them.

That would be [2] then? A little question here: AFAIK satelites vibrate
a lot. How do they account/compensate for the vibrations in the oscillators?

[2] "The Performance of Ultra-Stable Oscillators for the Gravity Recovery and
Interior Laboratory (GRAIL)", by Weaver, Garsecki, Reynolds
http://www.pttimeeting.org/archivemeetings/2010papers/paper28.pdf


> They run in a vacuum bottle (of course), and they have somewhat 
> obsessive attention to a lot of details.  But I suspect that aside from 
> the space qual aspects, the whole "how you build them" isn't a whole lot 
> different.

Is any of the design documents for those crystal oscillators available?
I would be very much interested to have a look at them.
 
			Attila Kinali

-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
		-- Tirin, The Dispossessed, U. Le Guin


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