Geckos on Russian space sex mission die in orbit

Five gecko lizards launched into space by Russia as part of a sex experiment have all died.

Scientists had hoped the lizards could offer some insights into weightlessness and sexual behaviour.

But it appears they may have frozen to death after the satellite's heating system malfunctioned, The Guardian reports.

The space satellite launched on July 19 and when it returned to Earth on Monday the four female lizards and one male on board were dead, Russia's space agency Roscosmos confirmed.

"We can say with confidence that they died at least a week before the landing because their bodies were partly mummified," said an official from Russia's Institute of Medical and Biological Problems.

The Russian space agency said it will appoint a commission to determine the exact cause of death.