Soyuz 7K-ST No. 16L (sometimes known as Soyuz T-10a or 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.
It was set to launch atop a Soyuz-U rocket on September 26, 1983. However, prior to launch, the rocket caught fire on its launch pad at Site 1/5, Baikonur Cosmodrome. The launch escape system of the Soyuz spacecraft fired two seconds before the launch vehicle exploded, saving the crew of commander Vladimir G. Titov and flight engineer Gennadi Strekalov. It is so far the only case in which a launch escape system has been fired with a crew aboard.
The mission was a visiting expedition to Salyut 7. The crew was scheduled to return in Soyuz T-9, leaving Soyuz T-10 for the crew on the space station to return in later. The failure briefly led to speculation in the West that the crew of Soyuz T-9 may be stranded on the space station, but this was never the case. That crew would return to Earth as normal on November 23, 1983, aboard Soyuz T-9.