"Space Center Houston Who hasn’t daydreamed about being an astronaut at least once?Thankfully, Space Center Houston makes it easy to learn about the great beyond. It’s the area’s No. 1 attraction for international visitors and the first Smithsonian Affiliate in the greater Houston area. The center features more than 400 space artifacts and several exhibitsrelated to the past, present, and future of America’s human spaceflight program. It’s also home to the world’s largest collection of moon rocks and lunar samples for public view, and offers guests the opportunity to go behind the scenes to see NASA's Johnson Space Center."