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dioxide produced, as well as heart contractions, lung function and blood pressure. Other tests using different gaseous mixtures examined the influence of gravity on lung function. Measurements of blood pressure in the 'great veins' close to the heart were conducted using the catheter inserted in Gaffney's arm during Columbia's ascent to orbit.

The catheter was inserted in his arm on 4 June, a full day before launch, and was removed about four hours into the mission. Its data indicated the degree of body fluid redistribution and the speed at which this redistribution occurred. The catheter revealed that Gaffney's blood pressure - not surprisingly - rose while on the launch pad, increased during ascent and then dropped closer to 'normal' within a minute of reaching orbit. This appeared to refute earlier theories that a rise in blood pressure results from fluid shifts to the upper body due to weightlessness.

A large number of blood-related experiments were also performed to investigate mechanisms responsible for decreasing numbers of circulating red blood cells -known as 'erythrocytes' - in space and a subsequent reduction in the oxygen-carrying capabilities of the blood. Samples were taken from the crew members before, during and after the mission and their volume to plasma was measured to check the rate of production and destruction of blood under 'normal' and microgravity conditions. Although the SLS-1 results did not provide conclusive answers, they indicated that a drop in red blood cell production was a contributory factor.

Televised downlinks from the Spacelab module were, by 7 June, showing what appeared to be a modern-day torture chamber, thanks to all the blood draws taking place. On one occasion, Gaffney calmly offered his arm to Hughes-Fulford for a needle and, within an hour, submitted to another test by Bagian. After one draw, Seddon told Mission Control that it was taking a little longer than expected to collect the blood samples. ''It's still running a little ragged because everything takes longer and veins are not cooperating,'' she said. ''But I think we're getting it all done.''

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