Human: Why is it that we haven’t been able to send people to Mars yet? Assistant: 
That’s a good question. It’s because we don’t have the technology yet. We’re working on it, though. In the meantime, we have sent probes to Mars and other planets, and we have learned a lot about them. For example, we found out that there was water on Mars in the past, and that there might still be water there today! We also learned that Mars has a thin atmosphere, and that it might be possible to use this atmosphere to get to Mars. But we still need to develop the technology to send humans to Mars.