3. It's tidally locked to Mars Deimos rotates in exactly the same time as it takes to orbit Mars, meaning that you'd only see one side of the moon if you gazed at it from the planet's surface.
Like our moon, Deimos is tidally locked to Mars, meaning the same side always faces the planet—the only side visible to rovers on the Martian surface. The only way to see Deimos’ far side up ...