[time-nuts] Space mission comes to an end because of a "computer time tagging" problem

[Magnus Danielson]

Jim,

On 09/21/2013 01:32 PM, Jim Lux wrote:
> On 9/21/13 2:30 AM, Rob Kimberley wrote:
>> David,
>>
>> The satellite has probably got a Rb as its clock (hopefully more than
>> one).
>
> Very, very few deep space probes carry a Rb ( I can't think of any off
> hand).  Regular old quartz, usually some sort of tcxo.  If they are
> doing radio science, then it might carry a USO, which is essentially a
> high quality OCXO.
>
<lots of nice description here>
> We typically monitor the "loop sress" on the receiver (essentially
> like watching the EFC voltage on a GPSDO) and if the locked tuning
> voltage starts getting close to the rail, people start to worry.
All this is really, keep the bird simple as simple can be and keep the
complexity at ground where we can fix it.

Upgrading firmware is sensitive, you just don't want to brick it.

Thanks for sharing.

Cheers,
Magnus