If you’re a serious fan of the United States space program and have your heart set on owning the 36-foot-long Apollo 11 flotation collar that was attached to the spacecraft’s command module by Navy swimmers helicoptered from the USS Hornet on July 24, 1969, a few days after Neil Armstrong and Buzz Aldrin became the first humans to walk on the moon, you're out of luck. That rubber, nylon webbing, and stainless steel piece of NASA history is part of the Smithsonian’s National Air and Space Museum. On the other hand, if you're yearning for a simpler NASA souvenir, such as a U.S. flag that has actually been to the lunar surface, you can pick one of those up for the relatively modest sum of $15,000, which is not bad when you consider how much it would cost you to safely transport a small bit of red, white, and blue silk to the moon and back again.

More accessible are NASA collectibles such as autographed photographs of astronauts, mission artifacts such as medals, patches, and pins, scale models of vehicle models, commemorative coins, postage stamps, and magazines with covers documenting NASA’s numerous achievements, as well as its handful of tragedies.

Patches are especially colorful and easy-to-collect keepsakes. The main NASA patch, known since its introduction in 1959 by employees of the National Aeronautics and Space Admini...stration as the “meatball,” is a circular patch with a white border, white letters, and two red lines that come together at an ascending point (that device is meant to represent flight). An elliptical white circle in the center of the patch is meant to suggest a spacecraft orbiting the Earth, while other white elements against a field of blue are supposed to be stars. The meatball patch was redesigned in 1992 as a blue-bordered “vector” patch, in which the red lines extend beyond the edges of the circle at the lower left and upper right.