Six University of Arizona engineering, math and biology students are getting set to turn somersaults in the name of research.
The students are members of the UA Microgravity Research Team, which is one of 18 U.S. undergraduate teams chosen to participate in NASA's 2014 Reduced Gravity Student Flight Opportunities Program. Acrobatics aside, their mission is to explore the effects of weightlessness on organic polymer synthesis.
Polymers are large molecules composed of many repeated subunits, called monomers. Naturally occurring examples include starch, cellulose and rubber. Synthetic polymers are used in a wide variety of products, ranging from replacement heart valves to sports helmets.
The team's research will lay the groundwork for onboard production of polymers for spacecraft repair, the fabrication of insulation for spacesuits, and materials production on long missions.
The UA Microgravity Research Team is at the Johnson Space Center in Houston for a visit that began May 30 and ends Saturday.
The highlight of the week will be a flight on NASA's Low-G Flight Research aircraft. This plane – called G-Force One – flies researchers and their experiments through a series of parabolic flight patterns in a weightless environment, topping out at 34,000 feet above the Gulf of Mexico.
After descending from the apex of a parabola, leveling out and beginning another ascent, humans and their gear are pinned to the floor by double the gravitational force humans experience on the Earth's surface. As the plane pushes over the top of the parabola, weightlessness takes over – the technical term is microgravity – and it's research time.
Microgravity aboard G-Force One lasts about 25 seconds, which calls for very efficient experimentation.
"All we have to do is flip a switch," said aerospace engineering student Ruben Adkins, founder of the Microgravity Research Team. The switch activates a heat gun aimed at test tubes full of organic liquid whose molecules have a structure based on chains of six carbon atoms. Gasoline molecules, by comparison, have chains of eight carbon atoms. The heat initiates the polymerization process and turns the liquid six-carbon monomers into a solid foam polymer made up of carbon chains thousands of atoms long.
The UA team's experiments are expected to address as yet unanswered questions. For example, is tensile strength improved in polymers that are fabricated in microgravity? What happens to density? Thermal resistance? Impact strength? The team has already conducted experiments on Earth to determine the properties of the foam polymer created at normal gravity. When the students return, they will conduct the same experiments on the foam created under microgravity aboard G-Force One and compare results to see how different gravities affect the polymer's properties.
"We're working in an area that hasn't been quantified before," Adkins said.
The plane is expected to fly as many as 35 parabolas, and the UA team had 26 tests planned.
When they're not working, they'll enjoy a G-Force One tradition: weightless playtime.
The gleeful somersaults, back flips and walks across the ceiling of the cabin last for only a few seconds. Then it's back to the padded floor for another descent and ascent.
The steep ascents and descents – with weightless interludes – can wreak havoc on the digestive system. Hence the plane's nickname: the Vomit Comet. All passenger flight suits have an airsickness bag tucked into the breast pocket. Unlucky users get belted into a seat for the remainder of the flight.
After their time aboard G-Force One, the Microgravity Research Team will analyze data and prepare a report. They're also planning educational outreach programs for Arizona schools.