Torture Chamber

Back inside the Spacelab module, the science crew - Ross, Harris, Walter and Schlegel - also conducted medical experiments using three painful-sounding facilities: Anthrorack, Biolabor and Baroreflex. Televised images from inside the module at various stages of the mission gave viewers the distinct impression of a medieval torture chamber, as the astronauts injected each other with saline as part of studies to replace bodily fluids lost during adaptation to microgravity and repeatedly took blood samples. Fortunately, as the 'flight crew' responsible for managing Columbia's systems, Nagel, Henricks and Precourt were 'immune' to these punishing medical tests.

''[We couldn't] get involved in any invasive experiments,'' Nagel said with a grin, ''which means they can't draw blood [from us]. They can't poke you with needles and things like that. They need you in good shape to bring the [Shuttle] home, which is okay with me!'' The Anthrorack facility (from the Greek word 'anthropos', meaning a human being) supported nearly two dozen medical experiments and was capable of performing the first-ever comprehensive, integrated screening of the astronauts' bodies in space. It could make simultaneous measurements of their respiratory, cardiovascular and endocrine systems and even had its own ultrasound device.

''Anthrorack is the most advanced of its type which has flown in space,'' said Dodeck. The facility enabled the astronauts to examine their cardiovascular, pulmonary and hormonal adaptation to the microgravity environment. Two other studies, funded by NASA, were the Baroreflex Experiment and the Cardiovascular Regulation Experiment. These investigated the relationship between post-flight cardiovascular 'deconditioning' and the baroreflex. Such deconditioning was highlighted by a characteristic drop in blood pressure when astronauts stood up after landing. It was associated with the decreased workload of the heart while in space and the baroreflex, which maintains appropriate blood pressure throughout the body.

The experiment tested the theory that light-headedness and a reduction in blood pressure after landing may be due to the fact that the baroreflex's ability to regulate it is somewhat reduced after having become adapted to microgravity. In particular, the ability of the body's blood pressure sensors to control the heart rate - known as the 'baroreceptor reflex' - was measured to determine if the predicted impairment did occur. To perform the experiment, astronauts wore a silicone rubber neck cuff, through which pulses of pressure and suction were transmitted to baroreceptors. Heart-rate changes were then recorded by an ECG.

All crew members also participated in 'saline loading' - drinking salty water in order to rapidly expand their intravascular volumes - to allow medical scientists to

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