However, when a probe is placed away from a star, the temperature is quite enough to damage electronic components and outer bodies of interstellar payloads.
As discussed in links within Is it bad if hydrazine freezes on a spacecraft? Is it always kept as liquid, or can it be safely allowed to freeze and then thawed when needed? and in answers there, we should remember that while freezing doesn't damage hydrazine, re-thawing hydrazine potentially damages spacecraft!
The solution here is to use the same technology that keeps other critical components sufficiently warm as discussed in other answers to keep the hydrazine lines and valves above the freezing point.
See also: