We can send robots to explore space without having to worry so much about their safety. Of course, we want these carefully built robots to last. We need them to stick around long enough to investigate and send us information about their destinations. But even if a robotic mission fails, the humans involved with the mission stay safe.
Sending a robot to space is also much cheaper than sending a human. Robots don’t need to eat or sleep or go to the bathroom. They can survive in space for many years and can be left out there—no need for a return trip!
Plus, robots can do lots of things that humans can’t. Some can withstand harsh conditions, like extreme temperatures or high levels of radiation. Robots can also be built to do things that would be too risky or impossible for astronauts.