How fabric works

37.5 technology – named for the optimal human body core temperature (in celsius) and the optimal relative humidity level (by %) – uses active particle technology to maintain a desirable microclimate next to the wearer’s skin. Using activated carbon sourced from coconut shells and volcanic sand, 37.5 has an array of apparel partners, including Adidas and Asics, not to mention the US military – and now ESA’s Couture in Orbit. 

At first the particles adsorb water molecules – like a landing strip for refuelling, where they can gather energy to go on – then body heat in the form of infrared light is absorbed by the particle and powers a pumping action to move the water molecules the rest of the way out of the system, creating a gradient from more to less water molecules.

The particles can also help to warm you when needed, returning absorbed heat to the body when limited water vapour is present.