Paul Calle (1928 - 2010) and Chris Calle (B. 1961) "1970s - Space Stations - Skylab" Signed lower right. Mixed Media on Illustration Board. Provenance: Collection of James A. Helzer (1946-2008), Founder of Unicover Corporation. This painting was originally published on the Republic of the Marshall Islands The 20th Century Series 60c Space Stations Orbit Earth stamp issued November 15, 1999. After man's historic walk on the moon in July 1969, the 1970s began a decade of unprecedented space exploration, with the United States and Russia developing both manned and unmanned spacecraft. On April 19, 1971, the USSR launched Salyut 1, the first prototype space station ever to be placed in orbit. Salyut 1 was used primarily as an observing platform to gather information on earth resources, meteorology, astronomy and space medicine. It also studied the effects of prolonged weightlessness. On May 14, 1973, NASA launched its own orbiting space station named Skylab. Its purpose was to allow astronauts to double the time they were spending in space, as well as study the effects of space on the human body, and enable clearer observations of the sun, moon, stars and planets. Image Size: 10.25 x 14.5 in. Overall Size: 13 x 23 in. Unframed. (B16581 / B16582)