From Works of Wonder:
"The 'sun' in this story is Isaac Asimov's symbol of Man's destiny among the stars, beckoning Earthlings to leave the womb of their home planet. The protagonist, Baley, comes to realize that humanity must go forth into space or face cultural stagnation. Using the sun metaphor as a jumping-off point, I posed Baley among the security of the trees, staring boldly at the sun--and at the call of space. The arrow is the symbol for a spaceship pointing the way outward from his heart. The robot holds the bow representing the means for using the arrow/spaceship because, as we find out later in Robots and Empire, robots are the force primarily responsible for the exodus of humanity."