Five geckos launched into space on board a satellite for an experiment on sexual reproduction in zero-gravity were found dead after their spacecraft returned to Earth, the Russian space agency said Monday.

The geckos became popularly known (in various iterations) as the "space sex geckos" in July. At that time, Roscosmos, Russia's federal space agency had lost contact with the satellite shortly after take-off as it hurled through space on July 19.

Contact was eventually re-established six days later, but it wasn't clear if the craft's life support systems remained functional during the communication blackout, or if the geckos survived during that period. 

The incident became a popular meme on social media around the world and even drew the attention of late night comedy hosts.

"All geckos, unfortunately died," Roscosmos said a statement. "The date and conditions of their deaths will be determined by specialists."

The geckos – one male and four females – were discovered in a frozen and mummified state when researchers reached the Foton-M4 satellite in a rural field where it landed after falling back to Earth. It was not clear if any of the reptiles mated while on their mission.

They were joined on the space flight by a colony of fruit flies, however, which the space agency said were found alive and healthy in a separate chamber within the satellite. The flies successfully produced several new generations of offspring during the 44-day experiment.