New theory emerges in Gagarin death mystery

Gagarin's death has generated countless theories over the years, ranging from a contract killing out of envy by Soviet leader Leonid Brezhnev to the idea that aliens may have taken their revenge on the space pioneer.

But the true culprit may have been a banal technical fault and an excessively fast descent for an emergency landing, Komsomolskaya Pravda said, quoting a member of the original inquiry into the 1968 crash.

Gagarin died at the age of 34 on March 27, 1968 -- just seven years after his historic space flight -- during a training flight on a Mig-15 in the region of Vladimir, some 190 kilometres (118 miles) east of Moscow.

The results of an inquiry into the crash have never been made public.

But former aviation engineer Igor Kuznetsov told Komsomolskaya Pravda that the jet's cabin had not been hermetically sealed and that Gagarin and co-pilot Vladimir Seryogin were forced to attempt an emergency landing.

Gagarin and Seryogin followed rules on descending for the landing from an altitude of around 4,000 metres to 2,000 metres but the drop was too sharp and they probably lost consciousness, causing the crash, Kuznetsov said.

"Somewhere between the altitudes of 4,100 and 2,000 metres they either lost consciousness or found themselves in a pre-fainting state. That's what would happen in a non-hermetic cabin," Kuznetsov said.

The death is likely to continue to be a mystery, however, as long as it is shrouded in official secrecy. The Kremlin in 2005 turned down a request by journalists and engineers to open archives on the crash.

On Thursday, an official from the research institute that keeps the remains of the fighter jet sealed in metal containers, was quoted by Interfax news agency as saying there was "no need" for another inquiry into the crash.