Laika's death was possibly caused by a failure of the central R‑7 sustainer to separate from the payload: this affected the thermal control mechanisms, which then caused the cabin to overheat. The true cause and time of her death were not made public until 2002; instead, it was widely reported that she died when her oxygen ran out on day six or, as the Soviet government initially claimed, she was euthanised prior to oxygen depletion.