From 9 a.m. to 5:30 p.m., visitors can tour sites such as Mission Control and the Sonny Carter Training Facility. where astronauts train in a large indoor pool. Nearby Ellington Field offers the Shuttle Training Aircraft and a chance to the see the KC-135A dubbed the "Vomit Comet."

Astronauts will be on hand throughout the day to answer questions and sign autographs.

Facilities used in advanced research such as life support systems, plant growth and physiological studies will also be open.

The X-38 crew return vehicle for the International Space Station and the inflatable Transhab will be on display.

In Teague Auditorium, presentations on the space station and Mars exploration will be offered all day. At 4 p.m. the Clear Lake Orchestra performs popular space music accompanied by space imagery.

The open house coincides with the annual Ballunar Liftoff Festival, a three-day event with about 100 hot air balloons, rides and games. Admission to the festival is $3; the JSC open house is free.

Johnson Space Center is located at 2101 NASA Road 1 in Houston.