1. The company has a permanent microgravity space lab on the space station.

2. She will conduct at least one of these classes, demonstrating how objects move in the microgravity environment of space.

3. It will also serve as a place to do scientific experiments in microgravity, or test technologies that will eventually go into orbit.

4. Without exercising, long periods of time in microgravity can cause muscles to shrink and bones to weaken.

5. Although microgravity can distort normal biology, conventional procedures for studying cells on Earth can introduce their own problems.

6. The parts and mechanisms of the ratchet had to be enclosed to prevent pieces from floating in the microgravity environment.