The man who saved millions of lives

Stanislav Yevgrafovich Petrov is a retired Russian Strategic Rocket Forces lieutenant colonel who, on September 26, 1983, potentially avoided a nuclear attack on the USA. Assuming that reports of incoming U.S. nuclear missiles from the satellites were in error, Petrov deliberately certified what otherwise appeared to be an impending nuclear attack as a false alarm, and some question exists as to whether he then reported what appeared to be a US attack. The computer reports were later confirmed to have been in error. Because of military secrecy and international policy, Petrov's actions were kept secret until 1998.
This incident is one of several high-risk decisions that were made by strategic nuclear forces over the years of the Cold War, often at the last minute, by administrative personnel far from the chain of command.

More here and here.

So let's hope the the human will never be fully taken out of the decision loop when it comes to using weapons like these!