The countdown began Monday with a favorable weather outlook. Because the nervous system regulates such critical bodily activities as blood pressure, sleep and balance, the outcome of the 16-day mission could shape plans to colonize space, NASA believes. And because the physical obstacles confronted by space travelers mimic many ills associated with aging and major disease, the results could improve health care on Earth as well, the agency contends. The latest mission is intended to complement similar research on the impact of prolonged weightlessness on cardiopulmonary function as well as the immune, skeletal and muscle systems.
Most astronauts find it hard to stand during their first days back on Earth.
The difficulty arises because the heart, which must work against gravity, cannot keep the brain adequately supplied with blood and the oxygen it carries until it re-acclimates to gravity. The fluids that fill the heads and chests of astronauts in space rush to the lower extremities as they land. During Columbia's mission, several of the astronauts will take turns placing their lower bodies into a portable vacuum chamber that will pull blood toward their legs. At the same time, another astronaut will insert a thin needle with an electronic amplifier into a nerve behind the leg. The apparatus will allow researchers to listen in and record the responses of the nervous system as it orders muscles to constrict blood vessels so blood pressure to rise.