Student Scientists Board NASA Aircraft for Weightless Experiment
Five Yale students have their feet firmly back on the ground after experiencing weightlessness while testing their self-designed and constructed experiment onboard a gravity-defying NASA aircraft this summer.
The students - known as the Yale Drop Team - conducted their experiment during two flights held June 26 and 27 at Johnson Space Center’s Ellington Field in Houston, Texas.
“The reduced gravity program was a once-in-a-lifetime chance to do real research and experience what only a fraction of humans ever experience - weightlessness. And it was even better the second time around,” says Greg Mosby ‘09, an astronomy and physics major and leader of the project.
The other Yale Drop Team members were Michael Boyle ‘10, Frances Douglas ‘11, Andrew Kurzrok ‘11 and Katherine Rosenfeld ‘10.
The Yale students were participants in NASA’s Reduced Gravity Student Flight Opportunities Program, which gives teams of undergraduates from across the nation the opportunity to propose, design, build, fly and evaluate reduced-gravity experiments. The Yale team’s plan was selected from more than 70 proposals based on its scientific merit and its educational outreach potential.
The Yale Drop Team did their experiment aboard NASA’s “Weightless Wonder,” a C-9 aircraft that produces periods of weightlessness lasting 18 to 25 seconds through “parabolic flight” - that is, by making a series of about 30 steep climbs followed by free falls over the Gulf of Mexico.
During their experiment, titled “Void Deformation in a Complex Plasma in Sub- and Super-Terrestrial Gravity,” the young scientists produced and imaged an argon complex plasma. The Yale Drop Team is now preparing a final report to NASA, with an analysis of the experiment’s effectiveness, scientific findings and conclusions.
The team’s short flight was the culmination of a “long history” of participating in the NASA program, says Mosby.
Two years ago, a group of Yale students began performing an experiment on Taylor cones, phenomena that occur when droplets of neutral liquids are subjected to large electric fields. The students knew the project would be suitable for the NASA program. “Microgravity was extremely fitting for droplet research because the droplet would simply float in place,” explains Mosby. “Microgravity would also eliminate the effects of gravity and possibly uncover new and different effects.”
However, there were problems with making the experiment free-floating; the needed equipment would weigh almost 150 pounds and use up to 30,000 volts of power - and NASA was not likely to let the droplets just float around the cabin, says Mosby. So, the drop experiment (from which the team derived its name) was retired, and at the end that year, most of the Yale Drop Team ‘07 graduated.
Last October, Mosby launched an effort to keep the Yale Drop Team going. He made up posters, and put them in places that might be frequented by likely candidates, such as Sloane, Becton and Dunham laboratories, and even the Yale Post Office. When he gave a presentation about the Yale Drop Team’s previous experiment to the Society of Physics, he invited interested students to join the effort to create a new project for the NASA program.
These efforts sparked the enthusiam of Rosenfeld, an astronomy major; Douglas, who plans to be a physics major; and Boyle, a biology major with expertise in computer aided design. Now there were enough members for a team, but time was short: A proposal was due to NASA by the end of that month. The students considered a variety of topics for their experiment, finally opting to focus on complex, or dusty plasmas - i.e., ionized gases that have micro-particles dispersed throughout.
“We thought that dusty plasmas were interesting because of their formation in the fabrication of computer chips,” Mosby said. “They also mirror the interstellar medium of our universe.”
Inspired by Professor Eric Dufresne’s course in “Fluid Mechanics,” Mosby recruited him as a faculty adviser. Their discussions with Dufresne prompted the students to think of dusty plasma as a solid material, rather than a gas. “We knew that solids deform under forces, and how they deform is determined by several calculable quantities of the system,” says Mosby. The young scientists decided to focus their experiment on measuring the effects of gravity on a dusty plasma, while capturing images of those effects with a CCD (charge-coupled device) camera, which forms images electronically, using a layer of silicon that releases electrons when struck by incoming light.
They researched past parabolic flights testing dusty plasmas and opted to mirror one of the first experiments with an argon dusty plasma. But the team still had a lot of work to do. “None of us had created plasma, and no one could remember a time when anyone at Yale studied them,” says Mosby.
The team began to scramble to meet the NASA deadline. Boyle designed a vacuum chamber. Rosenfeld took over the pressure system design and hazard analysis, making sure it would gain NASA approval. Douglas organized an outreach program featuring several trips to local Girl Scout troops to help them earn science badges. Mosby documented the science and procedures, and wrote a budget for funding. By Oct. 31, the 25-page proposal was out the door to NASA with signed approval from Dufresne. The preliminary work was done.
Then Mosby got an e-mail from Kurzrok, a freshman considering a major in physics, who was interested in taking part in the project. While each team can guarantee only four members “fly” with their experiments, ground crew alternates can participate in the projects. So, Kurzrok became the fifth member of the team. In late December, the Yale Drop Team ‘08 was officially in business when NASA accepted their proposal.
“After winter break, the real task began,” Mosby says. “NASA requires a Test Equipment Data Package or TEDP for each experiment. It is like the proposal without the science, and with the engineering and design aspect on steroids.” The Yale students had to have their experiment completely designed and structurally analyzed in graphic detail so NASA scientists and engineers could comment on its safety. This was due in May, and the team members still had a lot to learn about dusty plasmas.
They took a road trip to the Princeton Plasma Physics lab, where they met scientist Kurzrok Zwicker and saw their first dusty plasma. He gave them the insights they needed to start pulling things together.
They found information on the components they would need on Yale professor David DeMille’s wiki page. “The connection with DeMille also brought us our second and most important faculty adviser, Sidney Cahn,” says Mosby. “His suggestions and dedication helped us find resources and succeed.”
From pumps and vacuum chambers to accelerometers and thermocouples, the team worked to put together all of the pieces, and to make them work to NASA standards. Cahn encouraged them to enroll in a machine shop class at Yale taught by David Johnson. Mosby, Boyle and Rosenfeld spent hours in the student shop, bringing their chamber to size, making their own electrodes and designing components. Slowly, the chamber took shape.
Then came the challenge of fitting everything into a shipping container, getting it to Houston and finally to zero gravity. The needed packaging material cost $2,700, and the team’s budget with Yale Physics was already stretched. Mosby petitioned the master of his college, Gary Haller at Jonathan Edwards, for a summer research grant to help fund the experiment. The Yale Drop Team was rewarded with a Paskus grant to complete the frame.
Returning after a small break at the end of the academic year, Rosenfeld, Boyle and Mosby spent every day in Sterling Chemistry Laboratory, machining parts. Little by little, component by component, things came together. The setup was done, and it was time to test the system - and nothing happened. It wouldn’t generate the type of dusty plasma they needed. The students worked frantically, until finally: “At around 1 a.m. or 2 a.m. - time warps in the lab - we had the breakthrough,” recalls Mosby.
Time was getting short. It took two days to put the experiment together and four boxes to ship it. In Houston, they rented a U-Haul to transport it. Then, they had to build the chamber inside the U-Haul because they could not get into the NASA hangar on the weekend.
A plasma physicist in Houston gave them lab space and argon to test the system before flight and the NASA Test Readiness Review. There they successfully generated a plasma, and confirmed dust dispensing. A few glitches in the wiring were fixed, and they were ready.
The team presented their rig to the NASA subcomittee on June 23, and two days later Mosby, Rosenfeld and Kurzrok climbed onboard for their flight.
“As we rounded the top of the fifth parabola, I turned on the RF source [used to generate plasmas] and the dark screen of the webcam jumped to life with the characteristic purple glow of argon plasma. We did it! A few parabolas later, we activated our dust dispenser,” recalls Mosby.
Then the students took advantage of their weightlessness to have a little fun. Rosenfeld and Kurzrok did somersaults. Mosby did one-handed pushups.
On the second flight day, the students improved the laser alignments and set up the CCD camera. Douglas and Boyle went up and saw the plasma - and the dust. Although the CCD camera didn’t work, the webcam captured an image of what could be a dust cloud.
“Although we don’t have images to do science with yet, we can confirm the functionality of our experiment, and in the game of experimental science, this was a real success,” says Mosby. “We will most certainly re-fly this experiment after figuring out what went wrong with the optics.”
For more information about the Reduced Gravity Student Flight Opportunities Program, visit the website at http://microgravityuniversity.jsc.nasa.gov.
— By Janet Rettig Emanuel