An update from ESA’s Mission Science Office who support ESA’s science programme on the International Space Station. A look at the THERMOLAB experiment for which Expedition 30 crewmembers, André Kuipers, Don Pettit and Dan Burbank have recently completed experiment sessions in orbit.
Isn’t it amazing how the thermal control system can keep your house (hopefully) warm enough when temperatures outdoors drop below freezing? You set the temperature you want and sensors use that setting to decide when to heat.
At least as amazing is the thermal control in your body. The human body regulates its core temperature to ensure that the temperature for the vital organs is continuously at 37° C. Whether it freezes like recent winter weeks or whether you are lying on the beach in summer, your body is always able to keep your brain, heart, liver and kidneys and other core organs at this temperature. Sweating and shivering are two of the mechanisms that help your body’s thermoregulatory system maintain its temperature.
But what happens with the thermoregulatory system when you arrive in microgravity? It is not at all logical that it behaves the same as on Earth since, for example, the body fluids shift upward due to the absence of gravity. Without convection, sweating is no longer an efficient method of cooling down the body temperature – without gravity, warm air no longer rises up, cooling the skin in the process.
The THERMOLAB experiment looks at the changes in the thermoregulatory system in microgravity. It investigates how the body heats up during, and cools down after, exercise in microgravity. The measurements in space are then compared with those measured on the ground on the same crewmember before and after the mission.
For this experiment, André and his colleagues measure their body skin temperature during strenuous exercise, using two body temperature sensors positioned on the forehead (see image of André – for the purpose of this experiment, a newly developed thermo-sensor is used) and chest. The crewmembers are asked to exercise as hard as they can (as part of a NASA experiment called VO2max) – and will definitely sweat when performing the test – their heart rate, bicycle data and the amount of inhaled and exhaled oxygen helps the THERMOLAB science team to precisely analyse the body temperature curve.
Recently André and his colleague Don performed their third inflight session. Their colleague Dan has already completed four sessions. They do these measurements more or less once per month, to see how the thermoregulatory system evolves during their long-term stay on-orbit. Thanks guys, keep on exercising and acquiring valuable science data!