October 1, 2006 — Aboard NASA's "Weightless Wonder" airplane, physicists are experimenting with combustion and fluid flows in zero-g and developing a fire extinguishing system based on sound waves. The technique could be use to put out fires on the International Space Station and the Space Shuttle.
HOUSTON -- These students are on a mission.
"We're experiencing zero gravity right now. It's also the only place you can do that besides outer space," says a student from University of New Mexico in Albuquerque.
On board NASA's "weightless wonder" airplane in Houston, these aspiring physicists and engineers test out what could be the science breakthroughs of the future.
"Our experiment is dealing with two-phase fluid flows through the current filtration systems on the space station," a student from Oregon Institute of Technology/Southern Oregon University tells DBIS.
Students from Drexel University are working on how to processing bio-compatible polymers in two-g and zero-g.
And Dmitriy Plaks, a student at University of West Georgia in Clear Lake, Texas, says: "One of our main applications is for a fire extinguishing system aboard the international space station and shuttle."
Sounds easy enough, but here's the catch: Without gravity -- flames, water and hot air have a different shape than they do on earth. Water and foam can't always douse the flames in zero gravity. So the students are testing a theory -- using acoustics -- that sound waves can do the trick.
"In a zero-g environment, there's no up or down, so hot air or just any kind of air just sits there," Plaks says.
The team uses a candle and speakers to try and prove a theory that sound can cause pressure around a flame to drop, forcing it to go out.
There are some ups and downs with all the science projects ... And although the team didn't prove the sound wave theory in zero gravity here, they've shown that sound can extinguish small flames in their lab. The finding could help create new ways to put out fires in computer server rooms where water damage from conventional fire extinguishers can be costly.
BACKGROUND: The Prometheus Project is a research team made up entirely of undergraduate students who conducted experiments aboard NASA's "Weightless Wonder" airplane. They explored the use of sound waves to extinguish fires. This could be useful in exotic low-gravity environments like the International Space Station. It could also protect ordinary environments such as computer rooms, which could be damaged by using normal chemical extinguishers to put out flames. While the student researchers knew that sound can cause pressure to drop near a flame, they are working to figure out why exactly this happens. It might be due to a temperature decline at the site of the flame -- chilling the flame -- or a decrease in the concentration of oxygen, which would starve the flame.
CREATING ZERO G: NASA's turbojet simulates a weightless environment by alternating between upward climbs and downward dives to create an arc-shaped flight pattern. It's essentially a 10,000 foot roller coaster, and the arced flight patterns temporarily counteract earth's gravity to create a few seconds of weightlessness over several passes. During climbs, passengers feel almost twice the pull of earth's gravity, followed by a few seconds of zero gravity during the nosedives. It is used to familiarize astronauts with the sensation of zero gravity and teach them how to walk in space and on the moon.
ABOUT MOTION SICKNESS: The NASA turbojet is also dubbed the "Vomit Comet," because as many as 60 percent of passengers may experience motion sickness during flight. The crew has cleaned up an estimated 285 gallons of vomit over the years. Motion sickness is the result of the human body's internal balance system, adapted to function best under earth's gravity. Inside the inner ear are little canals with tiny hairs and fluid that can detect how the body is positioned in space. But aboard the G-Force One, the strength of gravity can be higher or lower than the inner ear is used to, and the shifts can lead to nausea.
WHAT ARE G FORCES? Acceleration is motion in which either an object's speed or direction (that is, its velocity) changes. Mathematically, acceleration and gravity are equivalent, just like energy and mass. A g is a unit for measuring acceleration in terms of gravity. g forces arise whenever something accelerates (as opposed to standing still or moving at a constant speed), because of the corresponding variations in the strength of gravity's pull. The faster something accelerates, the stronger the g forces.
The Acoustical Society of America contributed to the information contained in the TV portion of this report.
Note: This story and accompanying video were originally produced for the American Institute of Physics series Discoveries and Breakthroughs in Science by Ivanhoe Broadcast News and are protected by copyright law. All rights reserved.
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