When they first developed the organs of exploration, there was no there there. So they built timid, stupid machines and hurled them into the airless void to report back. Then they built idiot phone exchanges and put them in orbit to fill the void with chatter. Obsessed with biological replicators, they ignored the most interesting corners of the solar system and focused on dull, arid Mars. They periodically scurried up above the atmosphere and hunkered down in tunnels on Luna or ventured on expedition to domes on Mars, and they died in significant numbers before the end, simply because canned primates couldn't thrive in vacuum or survive solar flares.