What is happening to Mark Shuttleworth's body in zero gravity today?
Balance and sickness
Mark will still be floating around the space shuttle, but the awful space sickness is possibly already past. The brain and balance organs should have adjusted to the lack of gravity and the feelings of nausea and dizziness should have subsided.
Body fluids low
Mark's face should no longer appear puffy, but in the attempt to reduce what it sees as excess fluid, the body will have excreted an enormous amount of fluid.
This is normal, as the body adjusts to its new environment.
Urination levels should return to normal although the cosmonauts will be less thirsty than usual.
By now, the cosmonauts may have already lost as much as one-fifth of their blood volume as well as red and white blood cells.
This does not affect them negatively as the body has merely adjusted to the physical requirements of weightlessness.
The immune systems of the crewmembers will be weaker, and they will have to be cautious about hygiene to avoid infections.
The heart shrinks
The heart, which at first enlarged, has begun to shrink. It may have already shrunk by as much as a third.
Mark's heart rate should be slightly faster than the second day of his trip.
The weakening of the skeleton, that began on the first day, continues. Losing bone mass is one of the most serious effects of space travel.
A cosmonauts can lose up to one percent of bone mass per month in space.
Mark will exercise for two and a half hours per day to prevent bone and muscle loss. He will be strapped to his training apparatus to prevent him from flying all over the shuttle.
Cosmonauts can lose 10-20 percent of the muscle mass on a shirt mission. The muscles most affected by space travel are the leg and spine muscles.
- (Health24, April 2002)