This is an experimental block that was used to test the effects of artificial gravity on rats that was flown in space in 1977. On August 3, 1977, the USSR launched the satellite, Kosmos 936, also know as Bion 4, into orbit from the Pletsesk Cosmodrome. On board the spacecraft were 30 laboratory rats. Of the rats, 20 were exposed to the weightless environment, while ten were subjected to the equivalent of normal gravitational forces. This is the unit that held the rats that were to experience normal orbital weightlessness. The purpose of the experiement was to determine whether those rats who were weightless and those who were in units like this showed any differences in bone mass after 19 days in orbit. Scientists concluded that although there were diffences in bone mass between the rats that experienced weightlessness and those who did not, the greatest differences were found between those who were launched in orbit and those who remained on Earth in the control group.

The Soviet Institute for Biomedical Problems donated this unit to the Museum in 1979.