Apollo 15 postal covers incident in the moon landings, the public's fascination with items flown in space increased, as did their value. Although it was not publicly known until September 1972, 15 of the men who entered space as Apollo Program astronauts, before Apollo 15, had agreed with a West German named Horst Eiermann to autograph 500 philatelic items (postcards and blocks of stamps) in exchange for $2,500. This included a member of each mission between Apollo 7 (1968) and Apollo 13 (1970). These items were not taken into space. Covers were prepared by the crews and flown on Apollo 11, Apollo 13 and Apollo
Apollo–Soyuz Test Project Command/Service Module (CSM) with a Soviet Soyuz 7K-TM spacecraft. Although the Soyuz was given a mission designation number (Soyuz 19) as part of the ongoing Soyuz program, its radio call sign was simply "Soyuz" for the duration of the joint mission. The Apollo mission was not a numbered mission of the Apollo program, and similarly bore the call sign "Apollo". Despite this, some of the press and a few NASA web pages have referred to the mission as "Apollo 18", but this should not be confused with the canceled lunar mission. The Apollo spacecraft was launched with a docking module