U.S. space exploration history on U.S. stamps

In the United States, there are many stamps, or postage stamps, with pictures of special events or people on them. Some of these stamps have pictures that celebrate different events in the history of U.S. space exploration. For example, an stamps might have a picture of astronaut John Glenn, who was the first American to orbit the Earth in 1962. The stamp might also have a picture of space shuttle Discovery, which was the first reusable spacecraft. There are also stamps that show different Mars landings, or missions to the moon, or the Viking landers that explored the surface of Mars in the 1970s. All of these are examples of stamps that celebrate different events in the history of U.S. space exploration.