Soyuz 5's equipment module failed to separate properly following retrofire due to the misfiring of explosive bolts, and consequently blocked the re-entry heat shield on the base of the descent module. As a result of the added mass of the equipment module, Volynov lost control of Soyuz 5 which began to tumble, finally stabilizing itself with the thinnest part of the spacecraft facing forward. As the assembly entered the atmosphere, the stress and heat on the supporting struts between the modules finally made them burn through and part, allowing the equipment module to fall away and burn up on re-entry. Volynov could only wait while the descent module's automatic orientation system tried to regain control, which fortunately it managed to do with the heat shield facing forward.