An intrepid critter crew of geckos, mice and gerbils and other animals launched into orbit Friday (April 19) to begin a month-long Russian experiment to study how space travel affects living creatures. The space mission, scientists assure, will return the animals to Earth alive.

The new animal astronauts launched into orbit at 6 a.m. EDT (1000 GMT) atop a Russian-built Soyuz 2 rocket that lifted off from Baikonur Cosmodrome, Kazakhstan, in Central Asia.

The rocket carried the Bion-M1 space capsule, which is filled with enclosures for 45 mice, eight Mongolian gerbils, 15 geckos and numerous other species. They are expected to spend a month in orbit, flying 357 miles (575 kilometers) above Earth while scientists on the ground monitor the health of the capsule's passengers. [See photos of the Bion-M1 space animals mission]

"There has been a long history of this kind of biological research over the past 40 years, and NASA and the Russian side have been collaborating for that entire time, which is pretty remarkable. But each mission kind of brings a unique focus, be it the actual duration of the mission or the specimens being flown," Nicole Rayl, project manager for NASA's portion of the mission, told SPACE.com.