Phobos 1 was a failed uncrewed Soviet space probe of the Phobos Program, intended to explore Mars and its moon Phobos, launched in July 1988. The Phobos 1 probe failed on 28 August 1988 when a mistyped command deactivated crucial systems onboard the spacecraft. It was launched from Baikonur Cosmodrome aboard a Proton-K, with its twin probe Phobos 2. At 6,220 kg, they remained the heaviest interplanetary spacecraft until the 2011 Fobos-Grunt.