PSU in space

Portland State-based research on fluid dynamics is currently underway at the International Space Station.

On April 5, the National Aeronautics and Space Administration launched two sets of experiments designed by PSU researchers, which are being performed aboard the ISS.

The two sets of experiments launched by NASA are the Capillary Channel Flow experiment, in collaboration with a German research team, and the Capillary Flow Experiments (CFE), designed solely by the PSU team, according to Dr. Mark Weislogel, the principle investigator.

In general, Weislogal’s research and experience being run in the ISS lie in fluid dynamics, which is the study of how liquids and gases move.

These experiments have both applied and fundamental aspects, Weislogel said.

“The applied parts are learning how to manipulate fluid…in spacecraft systems without the benefit of gravity by just using clever selection of container geometry,” he said.

The goal of the CFE is to determine the best-shaped vessel in which to move fluids.

 “Without gravity, it is more difficult to control the flow of fluids and this is a challenge for designing spacecraft systems,” according to the summary of the research done by Weislogal’s team.

However, capillary forces—for instance, those which draw water uphill against the force of gravity— continue to act in the absence of gravity and can be exploited to control fluid orientation so that fluid systems on spacecraft perform predictably.

Weislogel said the research was motivated by “a need to process liquids with pumps, centrifugal forces, etc.” He and other researchers hope “to increase [the] reliability of spacecraft hardware from fuel tanks to toilets, to oxygen supply.”

The opportunity to launch these experiments is a great honor, because time and space are in such short supply on the ISS.

“[It’s] very difficult to get an experiment accepted for flight,” Weislogel said.

According to the project website, NASA requires that experiments launched to the ISS have a mass of less than 2.5 kilograms and a volume of less than two liters.

In short, any experiments and accompanying equipment must have approximately the same weight and volume of a two liter bottle of soda, or less.

In addition, experiments must also involve minimal crew training and have very low power requirements. 

Weislogel and his team designed the CFE to be “simple and intuitive,” meaning that they can be set up quickly and only run for two to three hours, he said. 

Weislogel said his team also had an advantage in that “we work in a niche area that seeks to learn both fundamental and applied aspects of microgravity fluid mechanics.”

The CFE involves 11 experiments in total. Four were launched April 5, while the other seven will follow later this year, Weislogel said.

According to Weislogel, “the applied parts [of the experiments] can be used directly by NASA and [the] aerospace community,” to make a number of improvements in the lives of those working at the ISS, from better managing waste to improving the reliability of oxygen flow.

“The fundamental stuff,” as in all basic scientific research, “is interesting and provides insight into possibilities down the road,” he said.

Weislogel, an associate professor of mechanical and materials engineering at PSU, said he headed a team comprised of graduate students and approximately a dozen high school students, as well as a research associate.

The graduate students involved—Ryan Jenson, Ben Semerjian, Noel Tavan and Alex Baker—are all working towards Masters of Science in mechanical engineering, Weislogel said.

The research associate, Senior Research Scientist Yongkang Chen, recently earned his doctorate from Purdue University and originally came to Portland State as a post-doctoral student.

The PSU team also worked in collaboration with a visiting scholar from Germany, Joerg Klatte, and Principal Investigator Michael Dreyer, both from the University of Bremen.

Weislogel, who earned his doctorate from Northwestern in 1996, worked for NASA for 10 years before joining the faculty at PSU.

Weislogel met and began working with Klatte and Dreyer in the 1990s while at NASA. Since then, they have collaborated on a number of projects, as well as in student exchanges and seminars.