A new Russian sea-based ballistic missile has failed in a test launch for the third consecutive time, signaling serious trouble with a weapon that has been hailed as a key future component of the nation's nuclear might, news reports said Wednesday. The Bulava missile failed during its launch Sunday from a Russian nuclear submarine, the daily Moskovsky Komsomolets reported. Two earlier tests, in September and October, also failed. The Russian Defense Ministry refused to comment on the report. "One of the most expensive and complicated nuclear weapons modernization programs faces the threat of failure," the daily Izvestia commented Wednesday.