During the 1950s and 1960s the
USSR used
dogs for
sub-orbital and
orbital space flights to determine whether human spaceflight was feasible. In this period, the
Soviet Union launched missions with passenger slots for at least 57 dogs. The number of dogs in space is smaller, as some dogs flew more than once. Most survived; the few that died were lost mostly through technical failures, according to the parameters of the test. A notable exception is
Laika, the first dog to be sent into orbit, whose death was expected from the outset.