Small Astronomy Satellites
- Series of three astronomy satellites of both scientific and political interest. Also called Explorer 42, SAS-A was launched by Italy from a platform off the Kenyan coast in 1970 and named Uhuru, the Swahili for freedom. SAS-B and C (Explorers 48 and 53) complete the series. Uhuru was the first satellite to construct a systematic survey of the X-ray sky and its results will be of use to astronomers for many years. SAS-B in 1972 carried much the most sensitive gamma-ray telescope ever placed into orbit, and operated until 1980. SAS-C again looked mainly at X-ray sources. All of these satellites weighed under 200kg each and only one was over a metre in any dimension, and they produced results out of all proportion to their cost.