It's pointing directly at Uranus.
NASA Drew This Giant Penis on the Surface of Mars
Apparently, this drawing of the male genitals etched into the surface of Mars—which has popped up on NASA's website—was just an amusing accident.
Either that, or a very dirty-minded individual got hold of the controls of NASA's aging Opportunity Mars rover--as if it wasn't bad enough that Opportunity got replaced by Curiosity and left on the red planet to die.
The appearance of this celestial schlong could, of course, be pure coincidence. Or even photoshopped—but the fact that it's on a NASA website either makes that unlikely or even funnier. Either way, it's still childishly amusing.