Some parts are easier to come by than others. Take the three original lunar rovers: They're still on the moon, and so are their tires — which posed a problem for NASA scientists trying to re-create the moon tires for a new lunar mission.
No one at NASA remembered how they were built, and the instructions had been lost. But it turns out that a spare was closer to home, stored for 40 years in the closet of the engineer who designed the original moon buggy. NASA is using it to build new ones.
Jeff St. Clair reports from member station WKSU .