Experience and science experiments have shown that while in microgravity, astronauts can loose up to 2% of their bone mass per month. In October 1998 a research project named OSTEO (Osteoporosis Experiments in Orbit) took place on board Space Shuttle Discovery using a Canadian-made cell culture system to measure bone loss in space.
The second phase of this research, OSTEO-2, will take place on board Space Shuttle Columbia, scheduled to launch on January 16, 2003. This Canadian space science project will study the molecular mechanism of bone loss in space, which should also benefit research on osteoporosis on Earth.