> Even Jupiter has very strong magnetic field Voyager I and II passed beyond
> of it many years ago.
> As much as I recall, they are still operating further the solar system at
> minus 200C degrees.
>
> What made that possible? (Special shielding?, unique manufacturing
> technique?, rare pcb designs?)

Each instrument on the spacecraft has a survival heater to keep it 
within -50 to +25C while powered off. When we do our temperature cycle 
testing we are required to do a power on at the two operating temperature 
extremes. The non-operating survival temperature is often a further 10-15C 
outside the operating extremes.

The instrument itself will often have enough heat dissipation to keep within 
the operating temperature limits without any help from other heaters. In any 
cases it is necessary to have active cooling, e.g. for sensors in cameras. 
Although the space environment is "cold" this does not keep the sensors 
cold, so there tend to be two operational temperatures used, 70k (liquid 
nitrogen) or <4k (liquid helium) depending on the sensor type and what the 
sensor is being used for.

> Besides, I remember that one or two year ago a PIC18F family MCU was used
> in a satellite, any news about the

That was in a Russian space suit that was launched from the space station. 
The batteries in it powering the electronics lasted only about 3-4 days. I 
doubt the PIC would have lasted much longer as I believe there was no 
shielding from the low earth orbit radiation, and the PIC was not tested for 
radiation resistance AIUI.

Typically satellites in low earth orbit require parts that are radiation 
resistant to 100k or 300k rads, depending on the exact orbit, instrument 
use, and lifetime requirements. COTS parts can often be used, but this 
typically requires giving at least one other part from the same production 
batch a radiation dosage test, and may also require a shield to be glued to 
the part that is flown. Such a shield is generally 1mm tantalum glued to the 
top of the chip, and another piece glued to the underside of the PCB. We 
always do this when fitting EPROMS in processor cards.

The aluminium case of the instrument also aids the shielding, and in some 
cases may provide enough shielding dependant on the position of the chip 
inside the instrument, and the orientation of the instrument on the 
spacecraft.

Interestingly the instrument I am currently working on will be taking its 
own Fe55 radiation source to the moon to calibrate its own sensors. Fe55 is 
a low energy radiation source which happens to work well for this purpose on 
this instrument. Because the instrument will be operating outside the low 
earth orbit radiation fields, we will be using a number of COTS parts. One 
PCB being supplied by another organisation, for our instrument, will be 
using commercial ICs throughout, and I don't think there is any special 
shielding on any of them. 

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