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Author Topic: How do instruments on space probes cope with ultralow temperatures?  (Read 2401 times)

Offline Mike Robinson

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Mike Robinson  asked the Naked Scientists:
   
Hello Naked Scientists,

I am newbielink:http://www.thenakedscientists.com/HTML/podcasts/ [nonactive] and newbielink:http://www.thenakedscientists.com/HTML/podcasts/ [nonactive]

My question is, what instruments on the Mars rovers must be kept warm from the bone chilling 200 plus degrees below zero? 

I understand that having the batteries freeze solid would not be a good thing.  I just want to know what other instruments must be kept at a relatively warm temperature?
 
Keep up the good work,
 
Cheers,
Mike from Michigan USA

What do you think?
« Last Edit: 09/03/2010 11:30:02 by _system »


 

Offline graham.d

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Good question. As far as the Mars Rovers are concerned they have to keep their electronics within reasonable temperature bounds and do so with arrangements of heaters and radiators (it can also get very hot on Mars). I don't know specifically how they do this but other spacecraft employ nuclear sources to provide heat.

Satellites in earth orbit can save power by controlling the heating from the sun by shading (using something like a parasol) and/or rotating to even out the heat absorbed. They also get a fair amount of heat from the earth, even at night. As spacecraft venture away from the sun the problem becomes worse of course. I believe it is a significant design problem.

Many electronic components will work down to very low temperatures though the change in the design parameters has to be taken into account. Generally they work better in fact. Any components for very low temperature use will have to be designed, packaged and tested to allow such operation. Generally this is easier than having to cope with very hot conditions but, because the demand is low for such devices, the cost is very high - not that this is too significant given other costs.
 

Offline Mike Robinson

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Thank you for the response Graham.d,
  You're right, I was not thinking that the rover's would have to dissipate a lot of heat.  The rover's landed around the equator of Mars.  Spirit recorded a high temperature of 5 C and  low temperature of -15 C.  I suspect that is summer day time temps. That is still on the cool side but if you take into consideration the heat that the rover's experience would be considerably more when you factor in the heat that the dark solar panels are absorbing.
  I do believe that they run subsystems of the rover's computer to generate heat.  Semiconductors do very well that low temperatures.  High end computer overclockers generally pour liquid nitrogen over the CPUs.  However I do not believe that electrolytic capacitors are that forgiving at low temperatures.
Thank you for your insight,
Mike Robinson
« Last Edit: 11/03/2010 14:45:26 by Mike Robinson »
 

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