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

[Jim Lux]

On 9/21/13 6:40 PM, Hal Murray wrote:
>
> jimlux at earthlink.net said:
>> 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.
>
> What stops working when things get cold?

Lots of things.  Mars gets *really cold* in the winter (-50C and lower)
There's an issue with plastic packages where it gets brittle.  CTE 
mismatches cause cracks, etc.  Electrolytic capacitors freeze.

>
> On Mars, the solar cells are pointed in the right direction.  Why doesn't it
> recover when the sun comes back in the Spring?

for Spirit, because of the issues with the wheel drive motors, it 
couldn't get into the right position to face the sun (on a south facing 
hillside, basically)

That 10-20 degrees makes a big difference because of the cosine (angle) 
problem/

>
>