Analysis of information sources in references of the Wikipedia article "Applications Technology Satellites" in English language version.
ATS-4 was to investigate the possibilities of a gravity gradient stabilization system. A Centaur upper stage failure stranded ATS-4 in a much lower than planned orbit, making the satellite nearly useless. Despite this, NASA engineers successfully turned on several of the experiments to collect as much information as possible during the craft's short life. The low orbit and resulting atmospheric drag caused ATS-4 to re-enter Earth's atmosphere and break apart on Oct. 17, 1968.
ATS-4 was to investigate the possibilities of a gravity gradient stabilization system. A Centaur upper stage failure stranded ATS-4 in a much lower than planned orbit, making the satellite nearly useless. Despite this, NASA engineers successfully turned on several of the experiments to collect as much information as possible during the craft's short life. The low orbit and resulting atmospheric drag caused ATS-4 to re-enter Earth's atmosphere and break apart on Oct. 17, 1968.