A memorial service has been held at a cosmodrome in Kazakhstan on the 50th anniversary of a space disaster in which more than 70 people died.
The BBC reports 24 October is known in Russia as the "black day" for space exploration
The disaster happened in 1960 when the Soviet Union tried to launch a new rocket known as the R-16, which exploded on the launch pad.
The rocket engineers, designers and officials were burned alive and asphyxiated.
Official files on the disaster described how many were vapourised in the huge fireball.
Soviet authorities immediately imposed a blanket ban on reports.
The papers were declassified only in the 1990s.