NASA's Biosatellite program was a series of three uncrewed artificial satellites to assess the effects of spaceflight, especially radiation and weightlessness, on living organisms.

Its primary goal was to determine the effects of space environment, particularly weightlessness, on life processes at three levels of organization: basic biochemistry of the cell; structure of growth of cells and tissues; and growth and form of entire plants and animals.

Prior to reentry, the entry capsule separated from the satellite bus properly, but its deorbit motor failed to ignite, leaving it stranded in a slowly decaying orbit.

[3] Biosatellite 2 carried thirteen biological experiments involving insects, frog eggs, plants and microorganisms.

[4] Despite returning approximately a day early, its 45 hours of earth-orbital flight enabled valid conclusions to be made in the thirteen experiments on board, by comparing the onboard samples to earthbound control organisms.