Originally posted on the Nature news blog. Posted on behalf of Katia Moskvitch.

Phew. Five experimental geckos that were feared lost in space have phoned home, restoring hopes that research into their zero-gravity sex lives can go on.

The four females and one male are onboard a satellite as part of an experiment to investigate sexual activity and reproduction in microgravity carried out by Russia’s space agency. Roscosmos launched the lizards using a six-tonne Foton-M4 rocket on 19 July. But the fate of the tiny cosmonauts became uncertain when their satellite briefly lost contact with ground control on Thursday 24 July.

Luckily, technicians managed to restore control on Saturday, and Roscosmos announced on its website that since then it has communicated with the satellite 17 times.”Contact is established, the prescribed commands have been conducted according to plan,” said Roscosmos chief Oleg Ostapenko.

Keeping the geckos company are Drosophila fruit flies, as well as mushrooms, plant seeds and various microorganisms that are also being studied. There is also a special vacuum furnace on board, which is being used to analyse the melting and solidification of metal alloys in microgravity.

Foton-M4 is set to carry out experiments over two months, and involves a “study of the effect of microgravity on sexual behaviour, the body of adult animals and embryonic development”, according to the website of the Institute of Medico-Biological Problems of the Russian Academy of Sciences, which has developed the project along with Roscosmos.

Specific aims of the Gecko-F4 mission include:

• Create the conditions for sexual activity, copulation and reproduction of geckos in orbit • Film the geckos’ sex acts and potential egg-laying and maximise the likelihood that any eggs survive • Detect possible structural and metabolic changes in the animals, as well as any eggs and foetuses

Scientists plan to perform additional experiments when Foton-M4 returns to Earth after its two-month mission. That is, assuming contact isn’t lost again. If contact with ground control was lost altogether, the satellite would stay in its 357-mile orbit for about four months, and then re-enter the atmosphere in an uncontrolled way and burn up.

Roscosmos engineers are now trying to figure out what led to the loss of control, with the main theory being that it may have been hit by space debris. The geckos’ craft is located in low Earth orbit, which stretches from about 160 kilometres above the planet’s surface out to some 2,000km. As a result, the intrepid lizards share the orbit with almost 20,000 objects, including more than 500 active satellites and the International Space Station, which circles the Earth at about 400 km above the surface.

It is not the first time Roscosmos has studied sex in zero gravity. In 2007, it sent a crew of geckos, newts, snails, Mongolian gerbils and cockroaches to space – and brought them back to Earth 12 days later. The cockroaches conceived while in space, and one, named Nadezhda, which means “hope” in Russian, became the first animal to give birth in space. Russian researcher Dmitry Atyakshin commented at the time that the roaches “run faster than ordinary cockroaches, and are much more energetic and resilient”.

Brace yourselves for super-geckos in September, when the current mission is due back on Earth.

This article is reproduced with permission from the Nature news blog. The article was first published on July 29, 2014.