Any mission where the crew gets back is considered a sucess, Take the first SKYLAB mission when the Skylab was launched in April 1973 one solar panel ripped off and the other became jammed and undeployed, only the quick inprov by the ground and the astros training in Houston saved the first mission because the station was overheating and threaten the project, so with a makeshift sunshade and a pair of pruning shears to cut a strap on one of the remaining panels, the missions carried on. Soviets do it all the time and our BY THE BOOK Menatilty had to change when the missions go awry....