What is the intended purpose of the Human-Powered Centrifuge for astronauts?

To provide short-duration gravitational loading to maintain bone density and cardiovascular function.

Short-radius centrifuges, such as those used in experimental setups, serve as a hybrid solution to the problems posed by long-term microgravity. Rather than spinning the entire ship, which is energy and material-intensive, individual crew members use the centrifuge for short periods to subject their bodies to gravity. This gravitational loading helps counteract the biological decline—specifically muscle atrophy and the loss of bone density—that typically occurs during long missions, allowing the rest of the ship to remain in a microgravity state for general living.