KENNEDY SPACE CENTER VISITORS COMPLEX

• Hours: 9 a.m.-5:30 p.m. year round, except Dec. 25 and certain launch days. Allow 5-8 hours, including the bus tour, which departs every 15 minutes.

• Fees: $38 adults, $28 child (ages 3-11), plus tax. Tickets are good for two days of admission and include the U.S. Astronaut Hall of Fame, filled with artifacts, six miles east of the Visitors Center.

Two added-feature bus tours, which have limited departures daily, are each $21 for adults, $15 for children, plus tax. There is also a lunch-with-an-astronaut option, for $22.99 and $15.99, plus tax.

• Information: 866-737-5235; www.kennedyspacecenter.com/.

• 40th anniversary events: On July 16, remarks by moonwalk veterans and other astronauts begin at 11 a.m. At 12:15, a new exhibit will open displaying such Apollo mission artifacts as space suits and tools that have been to the moon. Both are included in the basic admission; visitors should be at the Complex by 10 a.m. At 3 p.m. that day, Aldrin will autograph copies of his book, ``Magnificent Desolation: the Long Journey Home from the Moon.''

On the lighter side, the anniversary of the first moonwalk will be observed July 20 by letting visitors nosh on a 55-pound MoonPie, at 2 p.m.

JOHNSON SPACE CENTER, HOUSTON

''The astronauts train in Houston, but they launch at Canaveral,'' the Kennedy Visitors Complex tour guides proudly inform visitors. That translates to: You won't see a Vehicle Assembly Building or a shuttle on a launch pad at the Johnson Space Center, outside Houston.

But there, you might happen upon an astronaut in a special suit in an indoor pool, learning about weightlessness.

And you will see two authentic Mission Control rooms. The first stop on the basic tram tour is a room filled with computers and huge monitors, used in June 1965 for the first manned flight. It was at these consoles that engineers monitored the Apollo flights -- including Apollo 13, when Jim Lovell radioed back: ``Houston, we have a problem.''

The next tour stop is the current control room in which experts communicate with the astronauts aboard the Space Station and monitor its systems. Closed-circuit screens show those astronauts at work.

The trams drop visitors at an observation area above a large room holding mock-ups of Space Station and shuttle sections, in which astronauts practice, and at the building housing Houston's own Saturn V.

The trams also deliver visitors to a building called Space Center Houston, which has moon rocks, artifacts from space missions, interactive displays, video games (can you safely land the Shuttle at the Cape?) and a lift-off simulator.

There is also a zero-gravity chair that visitors try to maneuver to perform simple tasks (think of yourself as floating on a giant air-hockey table).

Space Center Houston is about 25 miles south of the city, in the Clear Lake area. It is open year-round, except for the major holidays.

Fees: $19.95 for adults, $18.95 for seniors, $15.95 for children ages 4-11. Parking is $5.

• Information: 281-244-2100; www.spacecenter.org.

U.S. SPACE & ROCKET CENTER, HUNTSVILLE

The third of the three NASA-affiliated educational complexes is the U.S. Space & Rocket Center, at Huntsville, Ala., where NASA engineers develop and refine the vehicles and propulsion systems.

This center offers interactive, kid-oriented exhibits: a ride that rapidly hurtles the passengers 140 feet high, another ride that subjects visitors to three times the force of gravity, and a climbing wall to indicate what working on Mars might be like.

The center also offers a variety of one-day and multi-day training programs for children and adults, learning what astronauts undertake.

The center is open 9 a.m.-5 p.m., daily except for the major holidays. Museum tickets are $20 for adults, $15 for children 6-12 and include rides; kds 5 and younger are admitted free. IMAX admission is additional as are overnight Space Camps.

• Information: 800-637-7223; www.spacecamp.com.

-- ROBERT N. JENKINS