Human analog missions are like playing "pretend" with grown-ups. They are a pretend mission on Earth that is designed to feel like a mission in space. Scientists and astronauts use these pretend missions to learn how humans might respond to being in space for a long time.
For example, they might pretend that they are living on the moon or Mars, and they have to wear spacesuits just like real astronauts no matter where they go. They will eat special space food and have to do lots of exercises to keep their bodies strong. They may even sleep in a small space, like a tiny room or tent, just like they would have to in a spacecraft.
During these pretend missions, scientists will watch how the people behave and how they interact with each other. They might even do tests to see how their bodies are doing, like testing their blood pressure or heart rate.
This helps scientists figure out how to make better equipment for space missions and what they can do to help astronauts be more comfortable and healthier while they are exploring space. Overall, human analog missions are an important way for scientists to prepare for a real mission to space in the future.