This is an experimental block that an international team of scientists used to test the effects of artificial gravity on rats. On August 3, 1977, the USSR launched the satellite, Kosmos 936, also know as Bion 4, into orbit from the Pletsesk Cosmondrome. On board the spacecraft were thirty laboratory rats. Of the rats, twenty remained weightless, while ten experienced the equivalent of normal gravitational forces through the rotation of this unit. The purpose of the experiment 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 differences in bone mass between the rats that experienced weightlessness and those who did not, but the greatest differences in bone density was between those rats that flew in orbit and the control group on Earth.
The Soviet Institute for Biomedical Problems donated this unit to the Museum in 1979.