With all the proposed moon landers and rovers, it seems to be a repeating topic that the moons 14 day/14 night cycle ends up killing the landers from a lack of solar power. I don't actually see why this is a problem. Are the batteries not able to take the cold and freeze? Or simply other mechanical issues? I can't imagine the cold would adversely affect the solar panels or electronics and prevent them from powering up once the sunlight returns. Yet every moon lander I've read about recently only lasts for X-days before the sun goes away. Why is this such a big problem? If it's the batteries, would you not simply use a solid state battery to solve the problem? No liquid cells...
Thanks in advance for info.
The night is very cold, -180 C or so. The electronics would have to be kept warm, which takes energy. Heat is hard to do as batteries aren't very energy dense.
You could probably do some basic maths to work out how much battery would be needed. I'll have a go too.
Mainly the batteries cannot get that cold, the chemistry is destroyed. Usually plutonium at minimum is used to keep them hot, sometimes also to generate electricity.
A "practical" alternative is to climb the corner of a south pole crater and extend a vertical solar array with perpetual light. There are only few spots available and at some point in the future there will be race to be the one there.
Another alternative is to use fuell cells. Or I guess you could even burn some propellant.
Once the mass is less of a problem I guess there will be solutions with more battery and heavy isolation
Thermal expansion and contraction. Different materials expand and contract at different rates when exposed to heat and cold. This will kill most electronics over time, and the Extreme heat and cold swings on the lunar surface from the day / night cycle means that basically everything breaks over time. You need really good insulation to avoid overheating during the day, and a heater that can be on the entire the lunar night in order to keep the electronics from freezing.
For example, the Chinese lunar rover, Yutu, did this by shutting itself off at the peak of the lunar day (for a couple of Earth days) to keep the peak heat low, and has nice radioisotope heaters for the lunar night.