PhobosThe Soviet Union loses all contact with the unmanned Mars probe Phobos 2 during a close flyby of the inner Martian moon Phobos, where the vehicle had been programmed to deposit a pair of surface landers. Unable to reacquire communications with Phobos 2, Soviet ground controllers later discover a fatal error in the programming of the probe’s on-board computer, leading to a loss of attitude control similar to the incident that doomed Phobos 1 in 1988. Since delivery of the landers never occurs, the mission is deemed a failure.