The planet doesn't have to rotate to use celestial navigation. As long as you can see the stars you are fine.
So the dark side of mercury would work fine. On the hot side as long as you are not exactly on the equator the sun acts as a fixed direction and you can use that.
> Anyone know if Mars has any polar stars?
The orbital tilt of Mars is 1.85 degrees (vs 0 for earth) and the Axial tilt is 25.19 vs 23.44 for Earth. So Polaris would be pretty close to being a polar star for Mars as well.
So the dark side of mercury would work fine. On the hot side as long as you are not exactly on the equator the sun acts as a fixed direction and you can use that.
> Anyone know if Mars has any polar stars?
The orbital tilt of Mars is 1.85 degrees (vs 0 for earth) and the Axial tilt is 25.19 vs 23.44 for Earth. So Polaris would be pretty close to being a polar star for Mars as well.