Scandinavia and the World

Comments #9754170:

Thank you so much Petrov 20 4, 4:02am

Wrong. Petrov's only role was to inform top political and military leadership of incoming attack and it's details. Final decision to launch counterattack or not would be theirs to make.

His instructions were not specific, but implied that he had to be reasonably certain of incoming attack - that means getting confirmation from long range radar stations as well, not just newly deployed satellite surveillance system.
Malfunction was indicated right from the start by the fact that only a single launch was detected, while any reasonably expected nuclear attack would involve hundreds of missiles launched from multiple bases.

Without radar detection of incoming warheads and given highly improbable pattern of attack, satellite alarm was rightfully disregarded as false. By some account instruction to wait for radar confirmation was given by an immediate superior who was informed of developing situation over the phone, by another version it was Petrov's own judgement.
Even if someone really wants to make a case for saving the world, list of saviors is entire chain of decisions from Stanislav Petrov to Dmitriy Ustinov.