A board of the National Academy of Sciences in the USA that investigated the scientific aspects of human space exploration. It was established in 1958 approximately six months after the USSR launched its Sputnik spacecraft. The SSB advised NASA, the US Department of Defense, and other bodies on the aspects and problems of crewed space flights and space stations, and interplanetary probes. The organization did much to convince NASA to focus on the planet Mars as the main element of the US planetary exploration programme. It dissolved in 1974.