The innermost seal of the new spacesuit will be made of a three-layer structure of "smart materials". So-called "smart material" is a material with a thick layer of polymer colloid sandwiched between two layers of polyurethane. If the polyurethane layer is damaged, the colloid will seep and solidify at the damaged part, automatically plugging the leak. Experiments conducted in a vacuum chamber show that this material can automatically repair holes up to 2 millimeters in diameter.