The Space Station Freedom will provide a wealth of new opportunities for life sciences research in the microgravity environment of Earth orbit. Such research will require the long-term housing of plant and animal subjects, as well as cell and tissue culture support systems. In addition to newly designed plant and animal vivaria for micro-g, housing for control subjects at one g and fractional g will be required to provide scientific controls, support gravity threshold studies, and perform experiments at Lunar and Mars gravity levels. A natural adjunct to a set of microgravity vivaria in space is, therefore, a centrifuge which could expose the same specimens to variable gravity levels. The larger the centrifuge, the more subjects that can be housed, the smaller the gravity gradient on the subjects, and the smaller the Coriolis effects. Early studies recommended a 4.0 meter diameter centrifuge, the largest that could be accommodated in a Shuttle launchable module. A series of accommodations studies, including programmatic, cost, and technical considerations have resulted in several possible options. Currently favored options include a 2.5 meter diameter centrifuge located in the end cone of a Space Station Freedom node or in an attached life sciences module. Such a device could support a mix of rodent, plant, small primate habitats, and other special purpose habitats. An automated cage extractor could be used to remove modular habitats in pairs without stopping the main rotor, minimizing the disruption to experiment protocols. Due to volume and other Space Station Freedom resource constraints, a 1.8 meter diameter centrifuge is also being evaluated.