The satellite re-entered Earth's atmosphere ten years after it had failed. During pressurisation of the satellite's propulsion system shortly after separation from its Ariane 4 launch vehicle, a pyrovalve firing created a leak that made the US$200-million satellite a total loss. The lawsuits that inevitably followed were later settled out of court.
At launch time, Telstar 402 was considered "one of the biggest, most powerful, most capable communications satellites ever built," according to its operator AT&T. It had a launch mass of 3,331 kg and a total on-board power of 6.4 kW at the beginning of its 12-year design life. It was equipped with 24 C-band and 16 Ku-band transponders.