These spacesuits look very retro today but were cutting edge back in the day. The astronauts who wore them were national heroes who inspired dreams of space travel in a generation of Americans. It's not surprising that these spacesuits are among the Smithsonian's most popular artifacts.
The spacesuits worn by the Mercury, Gemini, and Apollo astronauts are among the most asked for, and asked about artifacts in the Smithsonian national collection. It is true that explorers of remote, inaccessible, and environmentally inhospitable regions of Earth (notably of the Arctic and Antarctic regions), and test pilots since the 1930s, have required specially designed clothing of various sorts. It is a testament to the extraordinary cultural significance of spaceflight, however, that spacesuits attract far more attention than the parkas, snow shoes, flight jackets, and even pressure-suits and "crash helmets" of Earth-and-air-bound explorers.