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Astronaut airbags hold promise of a smooth landing

By

August 30, 2010

Sydney Do (right panel, at right) works on his prototype astronaut air bag system

Sydney Do (right panel, at right) works on his prototype astronaut air bag system

Should the astronauts living on the International Space Station (ISS) ever need to evacuate, the plan is that they will be able to board the station’s resident escape spacecraft, which will then take them back to Earth. That escape craft, called Orion, is currently under construction. Like the Apollo spacecraft that it resembles, Orion is intended to land at sea. If it should happen to come down on the land, however... well, those astronauts could be in for a rough landing. With that in mind, a graduate student in MIT’s Department of Aeronautics and Astronautics is developing an air bag system to cushion Orion’s occupants in the event of a dry landing. The system, interestingly enough, was inspired by the structure of seeds.

NASA originally proposed a 499 kg. (1,100 lb.) shock-mounted rigid structure upon which the astronauts’ seats would be mounted, but decided the system would be too heavy for dry landings. MIT student Sydney Do, however, came up with a smaller, lighter alternative: a reusable, 317.5 kg. (700 lb.) air bag system that could inflate during launch and landing, deflate for storage purposes, and partially inflate to provide seating while the vehicle is in space. His system is also purely mechanical, so it wouldn’t be subject to the whims of buggy or misinformed computers.

The origins of the system date back to 2008, when NASA astronaut Charlie Camarda helped students from MIT and Penn State explore how the physics of seeds could be applied to engineering principles. In the case of Do’s air bag system, each astronaut is surrounded in an individual “cushion of air,” just as protective fluid surrounds the embryo in a seed.

Unlike car air bags, which inflate upon impact, Orion’s air bags would already be inflated when the spacecraft hit the ground. The challenge with which Do and his colleagues were presented was one of figuring out the rate at which the gas should be able to vent from the bags. If it vented too fast, or if there wasn’t enough in there in the first place, the force of the landing would send the astronauts and their seats right through the bags and allow them to impact with the ground. If the gas couldn’t be displaced quickly enough, however, the downward kinetic force of the astronaut would compress the gas molecules within the bag, turning it into a spring that could actually rebound them up into Orion’s ceiling.

In order to avoid either of these scenarios, Do and his MIT team designed release valves that open at low pressure. These would allow the gas to keep the seat from hitting the ground on the initial impact, but would also have vented the gas as soon as Orion’s floor came to rest.

Utilizing computer models, Do now has a working prototype of his system, which consists of a seat equipped with four air bags, each one of which features two release valves about 15 cm. (6 in.) wide. He constructed the bags from vectran, a high-strength material that was used to cushion the landings of several of the Mars rovers. His prototype has been successfully put through dozens of dummy-equipped drop tests, from heights of up to three meters (ten feet). He is presently reviewing the test data, before presenting his final design to NASA this fall.

Orion was originally supposed to transport humans to the moon as part of NASA’s Constellation program, but that program was scrapped this February. Even if the spacecraft never even makes it as far as the space station, Do hopes that his system can be used in similar capsule-type space vehicles.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
4 Comments

I think it more economical and practical to design air bags for cars to protect them during impact since they are expensive investments. I am sure that insurance rates would decline and that having double air bag protection (external and internal) would promote the safety of individuals within the vehicle, pedestrians involved in crashes as well as decrease the damage to other cars and people during impact. The deployment would have to be in advance of any collision so that a good sensor/computer system would be necessary.

Adrian Akau
31st August, 2010 @ 09:07 am PDT

I think the whole things sucks....

I'd much rather see a seated "standing upright" ejection pod - that blows off with a small rocket at 300 Kmh, and it's capped with a wee drogue chute to slow it down during re-entry and enable a fast drop down through the upper atmosphere, to 5,000 meters where a main "sky diver" style parachute opens.

Even combining a single user tube compartment, with a set of pop out wings - would be an advantage to enable long range gliding to landfall - and near populated areas - would be even better.

Mr Stiffy
31st August, 2010 @ 08:45 pm PDT

WOW terrible design, overly complex, multiple points of failure. I could do better with 100lbs of carbon fiber. I have jumped off a roof 40 foot roof onto firm grass with a device that ways 15lbs with out any injury or even getting dirty...

Michael Mantion
1st September, 2010 @ 11:56 am PDT

The cosmonauts have been landing on ground for a long time. They really don't have much choice. An amazing (to me, at least) technique they use is to have a meter long feeler that sticks out the bottom of their landing pod. When the feeler feels the ground, retro rockets fire, cushioning the landing.

Brillig
1st September, 2010 @ 01:52 pm PDT
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