A TEAM of Russian gecko cosmonauts have all perished in the line of duty, the Russian Federal Space Agency has revealed.

The reptiles were popularly referred to as the “sex geckos” because of their two-month mission to test the effects of zero-gravity on reproductive systems, the Moscow Times reports.

The four females and one male were tasked with mating in space, in the name of science.

Although there were teething issues with the experiment, when Russia lost contact with the science module the creatures were travelling on, authorities were soon able to report everything was in order.

EARLIER: Russia regains control of ‘sex gecko’ satellite

Soon after launch, the Foton-M4 research satellite failed to respond to commands designed to activate its engines for a boost to a higher — safer — orbit, prompting fears the five Mauritius ornate day geckos would perish in a fire when re-entering the atmosphere.

Then, suddenly last week, the Russian agency announced the mission was complete, after only 44 days. The geckos had been sent into space with food and water supplies for several months and were not expected back to Earth until later this month.

The satellite landed in Orenburg, Russia, on Monday afternoon, at which point it was revealed the 12-centimetre space travellers had died.

“All the geckos, unfortunately, died,” a statement by the Russian Academy of Sciences’ Institute for Medical-Biological Problems said, adding that the exact date, time and cause of death will be determined by specialists in Moscow.

The reptiles’ fellow space-travellers — a team of Drosophila flies — came to no apparent harm and successfully reproduced, according to the statement.