Soyuz 7K-ST No.16L
Soyuz 7K-ST No.16L, sometimes known as Soyuz T-10a or Soyuz T-10-1, was an unsuccessful Soyuz mission intended to visit the Salyut 7 space station, which was occupied by the Soyuz T-9 crew. However, it never finished its launch countdown; the launch vehicle was destroyed on the launch pad by fire on 26 September 1983. The launch escape system of the Soyuz spacecraft fired six seconds before the launch vehicle exploded, saving the crew. This is the only time a launch escape system has been fired before launch with a crew aboard.