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

[Hal Murray]

albertson.chris at gmail.com said:
>> What stops working when things get cold? >
>> On Mars, the solar cells are pointed in the right direction.  Why doesn't 
it
>> recover when the sun comes back in the Spring?

> They run out of power for running the battery heaters, then the battery
> freezes and fails.  The batteries get to such a low temperature that they
> are unable to be charged.  The rover was never designed so that it could
> move and operate under solar power.  It is really battery powered and uses
> the panel for charging. 

We are talking about running computers and radio gear rather than motors.

I can see running motors in bursts from batteries, but computers and radios 
generally run continuously so they shouldn't need a battery when the sun is 
up.

Am I missing something?  Can't the computers and radios run off solar power 
when the batteries are dead?  Does the receiver take more than (ballpark) 
peak solar-cell output under nasty conditions?


jimlux at earthlink.net said:
> That 10-20 degrees makes a big difference because of the cosine (angle)
> problem/ 

I understand that it could make the critical difference, but COS 20 is still 
close to 1.  It's probably lost in the noise of how much dirt is on the solar 
cells.



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