Thursday, September 18, 2014

MIT Spacesuits: A streamlined second skin

The MIT BioSuit, a skintight spacesuit that offers improved mobility and reduced mass compared to modern gas-pressurized spacesuits. Credit: Jose-Luis Olivares/MIT

For future astronauts, the process of suiting up may go something like this: Instead of climbing into a conventional, bulky, gas-pressurized suit, an astronaut may don a lightweight, stretchy garment, lined with tiny, musclelike coils.

She would then plug in to a spacecraft's power supply, triggering the coils to contract and essentially shrink-wrap the garment around her body.

The skintight, pressurized suit would not only support the astronaut, but would give her much more freedom to move during planetary exploration.

To take the suit off, she would only have to apply modest force, returning the suit to its looser form.

Now MIT researchers are one step closer to engineering such an active, "second-skin" spacesuit: Dava Newman, a professor of aeronautics and astronautics and engineering systems at 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.

Dava Newman
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 equaled that required to fully support an astronaut in space.

Several actuators aligned into a 3-D-printed cartridge structure, paired with passive fabric to form an active tourniquet, and mounted on a rigid object approximating a human limb. 

Credit: Jose-Luis Olivares/MIT

"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," says Newman, who has worked for the past decade to design a form-fitting, flexible spacesuit of the future.

"We want to achieve that same pressurisation, but through mechanical counterpressure, applying the pressure directly to the skin, thus avoiding the gas pressure altogether."

"We combine passive elastics with active materials. … Ultimately, the big advantage is mobility, and a very lightweight suit for planetary exploration."

The coil design was conceived by Bradley Holschuh, a postdoc in Newman's lab. Holschuh and Newman, along with graduate student Edward Obropta, detail the design in the journal IEEE/ASME: Transactions on Mechatronics.

More information: "Low Spring Index NiTi Coil Actuators for Use in Active Compression Garments." Holschuh, B Obropta, E. ; Newman, D. Mechatronics, IEEE/ASME Trans, Volume: PP Issue:99, DOI: 10.1109/TMECH.2014.2328519

No comments:

Post a Comment