Gen-next spacesuits to resemble a second skin

MIT scientists are working on a gen-next spacesuit that will be a snug, flexible outfit that automatically tightens up to a proper fit at the touch of a button.
Instead of climbing into a conventional, bulky, gas-pressurised suit, an astronaut may don the lightweight, stretchy garment, lined with tiny, muscle-like coils.
They would then plug in to a spacecraft's power supply, triggering the coils to contract and essentially shrink-wrap the garment around their body.
The skin-tight, pressurised suit would not only support the astronaut, but would give them much more freedom to move during planetary exploration, researchers said.
To take the suit off, they would only have to apply modest force, returning the suit to its looser form.

Dava Newman, a professor of aeronautics and astronautics and engineering systems at Massachusetts Institute of Technology (MIT) and her colleagues have engineered active compression garments that incorporate small, springlike coils that contract in response to heat.

The coils are made from a shape-memory alloy (SMA) - a type of material that "remembers" an engineered shape and, when bent or deformed, can spring back to this shape when heated.
The team incorporated the coils in a tourniquet-like cuff, and applied a current to generate heat. At a certain trigger temperature, the coils contract to their "remembered" form, such as a fully coiled spring, tightening the cuff in the process.

In subsequent tests, the group found that the pressure produced by the coils equalled that required to fully support an astronaut in space.
"With conventional spacesuits, you're essentially in a balloon of gas that's providing you with the necessary one-third of an atmosphere (of pressure) to keep you alive in the vacuum of space," said Newman.
"We want to achieve that same pressurisation, but through mechanical counter-pressure - applying the pressure directly to the skin, thus avoiding the gas pressure altogether," Newman said.
The coil design was conceived by Bradley Holschuh, a postdoc in Newman's lab.
While skintight spacesuits have been proposed in the past, there's been one persistent design hurdle: how to squeeze in and out of a pressurised suit that's engineered to be extremely tight.

That's where shape-memory alloys may provide a solution. Such materials only contract when heated, and can easily be stretched back to a looser shape when cool, researchers said.
To find an active material that would be most suitable for use in space, Holschuh considered 14 types of shape-changing materials - ranging from dielectric elastomers to shape-memory polymers - before settling on nickel-titanium shape-memory alloys.
When trained as tightly packed, small-diameter springs, this material contracts when heated to produce a significant amount of force, given its slight mass - ideal for use in a lightweight compression garment.
The finding was published in the journal IEEE/ASME: Transactions on Mechatronics.