A Russian rocket carrying a capsule filled with 45 mice and 15 newts along with other small animals blasted off Friday on a month-long orbital mission that should pave the way for manned flights to Mars.
Live footage on the Roscosmos space agency website showed the Soyuz lifting off at 1000 GMT from the Russian-leased Baikonur space centre in Kazakhstan with its treasured cargo and another experimental satellite on board.
The so-called Bion-M capsule is also carrying snails and gerbils as well as some plants and microflora.
"This is first and foremost to determine how our organisms adapt to weightlessness and to understand what we need to do to make sure that our organisms survive extended flights," the TsSKB-Progress space research centre's department head Valery Abrashkin told state television.
The meticulously-prepared experiment will last 30 days and see the capsule touch down softly with the help of a parachute in the central Russian Orenburg region on May 18.
A field research lab will be deployed on site to quickly test the animals' response to their journey and return to Earth.
The missions has been widely publicised by the state media as a unique experiment that no other country has pulled off in the past.
The Vesti 24 rolling news station even added a touch of drama by noting that two of the male mice got into a deadly fight during the course of preparations and "as a result, the entire crew (of mice) had to be urgently replaced."
Russia has long set its sights on Mars and is now targeting 2030 as the year in which it could begin creating a base on the Moon for flights to the Red Planet.
But recent problems with its once-vaunted space programme -- including the embarrassing failure of a research satellite that Moscow tried sending up to one of Mars's moons last year -- have threatened Russia's future exploration efforts.
President Vladimir Putin this month unveiled a new $50 billion drive for Russia to preserve its status as a top space power.
Those plans include the construction of a brand new cosmodrome from where humans will fly to space by the end of the decade.
Russia's trials and tribulations are watched closely by other space-faring nations because the Soyuz represents the world's only manned link to the constantly-staffed International Space Station.
But Russian scientists said the experiments being conducted on the mice and other animals would have been impossible aboard the station because they pose a sanitary hazard.
The experiment's designers said the tests will primarily focus on how microgravity impacts the skeletal and nervous systems as well organisms' muscles and hearts.
The small menagerie will be accompanied by 24 measuring devices and other scientific objects that will also be stationed outside the capsule to measure radiation levels.
The animals will be stored inside five special containers that will automatically open after reaching orbit and close once it is time to return to Earth.
France's Centre National d'Etudes Spatiales (CNES) space centre said 15 of the 45 mice came from a French research lab that is cooperating with the study.
It added that five of the French mice came equipped with implanted sensors measuring their heart rates and blood pressure.
The capsule is scheduled to spin 575 kilometres (357 miles) above Earth.