Samantha Kreppel’s studies have taken her a lot of places in the three years she has been at Carthage. She spent a semester studying in Vienna, Austria. She is spending this summer researching Bose-Einstein Condensates in Washington. But a high point of her travels was the day she spent bouncing around NASA’s “Vomit Comet” like she was on the moon.
Kreppel, ’10, was one of six Carthage physics majors to travel to the Johnson Space Center in Houston in Spring 2009. She conducted research, toured NASA facilities, and met NASA scientists and astronauts. Joining her were Isa Fritz, ’10; Brad Frye, ’10; Erin Martin, ’09; Joseph Monegato, ’09; and Caitlin Pennington, ’09. The team conducted experiments aboard NASA’s microgravity aircraft to determine the dynamic angle of repose of lunar soil in lunar gravity.
“The flight was amazingly wonderful,” said Kreppel, a physics major and math minor from McHenry, Ill. “The flight made all the work, stress and long hours (preparing for the trip) worth it. I absolutely loved the feeling of weightlessness.”
“It’s like nothing you’ve ever experienced before,” agreed Brad Frye, from Spring Grove, Ill. “It’s amazing.”
An Elite Group
The Carthage team was selected by NASA to participate in its Systems Engineering Educational Discovery program, or SEED.
SEED pairs NASA researchers with college students to design and build experiments that support NASA’s research priorities, said Carthage physics professor Kevin Crosby. Prof. Crosby acted as the faculty mentor for the project, and joined the students March 25-April 4 in Houston.
“The great thing about the SEED program is that you are working on a project that is of great interest to NASA,” Prof. Crosby said. “You complete a design for a problem that is specified by one of the NASA field centers. They want the data; they use the data.”
Carthage was one of 10 schools nationwide selected to participate. “We were there with all these Big-10 engineering schools, schools like Purdue and Stanford and Brown and Cal-Tech,” Prof. Crosby said. “We were the only ones from a liberal arts college.”
A team from Carthage also participated in SEED in 2008, studying the efficiency of lunar dust filtration systems, essential to astronaut health. This year the team concentrated on a project essential to safe excavation and mining on the moon: lunar soil’s angle of repose.
The angle of repose is an engineering property of granular materials. “If you look at any sand pile, a grain hill on a farm, or a salt mine, they all have this very conical shape,” Prof. Crosby explained. “If you were to measure the angle that the sides make, it’s a constant angle for a given material. … It’s the point at which everything has to slide. Engineers need to know this angle to prevent collapse during any kind of engineering work.”
The Carthage team studied the dynamic angle of repose for various lunar dust simuli. They constructed a large rig with three rotating drums. Each drum held a simulant, and a camera filmed the slope each simulant formed upon rotation. Designing and building the rig was a difficult process that took months. “There were a lot of sleepless nights,” said Erin Martin, a physics major from Lemont, Ill., who graduated from Carthage in May.
The results were surprising. Gravity had a much greater effect on lunar dust’s angle of repose than the students expected. “On Earth, that dust settles at almost a 45-degree angle,” Martin said. “In lunar gravity, we were watching the drum and just seeing the angle go up, and up, and up, until it was almost at a 90-degree angle.”
“It was almost vertical,” said Brad Frye. “The gravity definitely impacts the angle. I wasn’t expecting it to be so dramatic.”
The Weightless Wonder
The experiments were conducted over two days aboard NASA’s Weightless Wonder. Previously nicknamed the Vomit Comet, the plane flies a series of rollercoaster-like dips and climbs over the Gulf of Mexico.
Passengers experience 2 G’s during each ascent — “You can hear the engine screaming and it definitely feels and sounds like something a plane shouldn’t be doing,” said Prof. Crosby. At the top of each parabola, passengers experience about 30 seconds of reduced gravity. The maneuver is modified to simulate zero gravity, lunar gravity (1/6 G) or Martian gravity (1/3 G). The plane flew mostly lunar parabolas for the students’ experiments.
“The plane basically drops out of the sky, and then climbs back up, and drops again,” Martin said. She compared it to jumping on a trampoline in slow motion. Moving purposefully is difficult. “It feels like you’re swimming, but there’s no resistance, so when you do this” — she makes swimming motions — “nothing happens. You feel like you have very little control.”
Passengers experience about 30 parabolas in all. “Most people felt fine,” Frye said. “We saw a few people from the other teams get their barf bags and have to go to the seats at the back of the plane.”
While the Weightless Wonder was a highlight of their time in Houston, the students also enjoyed touring the Johnson Space Center. “It’s the center for human space flight operations,” said Prof. Crosby. “Johnson is the only place that astronauts live and train. For that reason alone, it’s exciting to see.”
Students toured NASA’s mission simulators and saw the neutral buoyancy lab — the world’s second largest swimming pool — where astronauts do weightlessness training. They also met retired astronaut Barbara Morgan, who was Christa McAuliffe’s back-up for the Challenger mission, and the crew of the Space Shuttle Discovery, who just returned from the International Space Station.
Martin was excited to meet Discovery flight engineer Sandra Magnus. “Isa (Fritz) and I went to her and said, ‘We want to be astronauts.’ A lot of times when you tell people your dream is to be an astronaut, they look at you and think you’re ridiculous. It was nice to hear someone who’s been there say, ‘You guys can do this. You can’t give up.’ It was awesome.”
Kreppel said the entire experience was incredible. “Each stage of the process provided its own lessons,” she said. “While researching our experiment topic, I learned how to read journal articles and research papers. … During the design phase, I learned the complex but extremely important process of systems engineering. … I also learned to write grant proposals and research reports, which are very important skills for a scientist.
“I gained experience that would be otherwise unattainable in a classroom. I gained hands-on, life experience.”