NORFOLK, Va. (AP) — High school students in Virginia got to learn Thursday about the challenges of life in microgravity directly from an American astronaut aboard the International Space Station.

During a 20-minute video chat, Drew Feustel discussed the challenges of sleeping, showering and even thinking — it's called "space brain" — aboard the orbiting facility.

And yet his dreams have been pretty normal, he said when questioned about that by a student.

"I have not had any dreams in space that had me in space as well," he said, floating in a compartment packed with boxes, tubes and wires.

The talk was part of NASA's effort to boost interest in science, technology, engineering and math. The students were visiting NASA's Wallops Flight Facility on Virginia's Eastern Shore. The site is where unmanned rockets occasionally blast off to the space station carrying supplies and fresh food.

The Michigan native has been on the space station since March. One of the challenges for him is sleeping. He never feels like he's lying down.

"I don't know about you, but I always feel relaxed when I lay down on my back or my side and put my head on a pillow ... ," he said. "But in space, I feel the same way floating inside my sleep quarters as I do right now. My body is in the exact same position."

Human organs also float. So, food can feel like it's hovering in the upper chest. But the digestive system continues to work, and "what comes in still comes out."

Traditional showers are impossible. Water doesn't fall like it does on earth. Astronauts take sponge baths.

When air fails to properly circulate in a corner of the space station, astronauts can breathe in too much carbon dioxide. That can lead to "space brain" or thinking less clearly.

Feustel said a fellow astronaut once asked him to replace a tool they were using with another one. He went to retrieve it and returned with the exact same tool.

But his altered life on the space station is worth it, he said.

"Fundamentally, the basis of what we're doing in space is to try to ensure the human civilization can continue to live," he said. "All we have to do is look back to the dinosaurs to know that a single planet species cannot last forever."