Some people collect because of personal reasons, saving/displaying an item gives them pleasure. Some people collect for financial reasons, to diversify their holdings. Regardless of why, collecting the space race is very popular and is gaining increasing attention.

Since the original Mercury 7 astronauts were announced, people have been fascinated by space and collected a variety of items mostly to capture a piece of the thrill that the space program provided them. Today, a range of materials is out there -- from stamps and first day covers to medallions to autographs to commercially-produced items.

For those that collect because they love, choose a theme and run with it. For those curious about collecting for financial reasons, there is a value hierarchy.

Flown material such as flags, documents, medallions, etc are the most desirable with mass market books on the space program at the bottom. And of course rarity and coolness play a big factor. Even within the category of 'flown items' there is a hierarchy:

1. Apollo program items that went to the surface of the Moon
2. Apollo items that went to lunar orbit
3. Items that went into space during the Mercury, Gemini, Apollo programs
4. Items that went into space during the Space Shuttle/Space Station era
5. Medallions with material from flown missions follow the same hierarchy.

Similiarly with autographs, some are rarer and hence worth more than others. Neil Armstrong, as the first person to set foot on the Moon and someone who rarely autographs items, it highly prized. Likewise :

1. photos signed by the Apollo 11 crew,
2. those signed by the Apollo 1 crew who died in a fire in 1967,
3. and that of the first astronauts, the Mercury 7.

Fakes do abound and a number of autographs might actually be an autopen or signed by an assistant. There are several books and websites that have been created to help collectors identify whether they have an original.

Obviously when collecting anyone, one should check the provinance of the item -- fakes abound, especially on higher-dollar items and Russian autographs/documents. Several reputable auction houses offer appraisal services and hold space auctions throughout the year.