Spreading its solar-power panels to catch the last feeble light of day, the Rocky 7 patrols the Mars Yard of the NASA Jet Propulsion Laboratory in Pasadena, California. Controlled by an operator (visible in shed window), it is working in dimly lit conditions like those it will face on Mars, which is much farther from the Sun than the Earth is. From the book Robo sapiens: Evolution of a New Species, page 125.