Floating Discoveries: University Researchers Find Results in Zero Gravity

Credit: NASA

WASHINGTON (NASA PR) — A test tube drifting in midair and a computer tablet slowly turning are fun moments for the scientists who experience brief periods of weightlessness during parabolic flights. However, the science that’s taking place is no joke. NASA’s Flight Opportunities program makes it possible for U.S. researchers to take experiments out of their laboratories and into zero gravity for some for serious research with a bit of levity.

Eliminating gravity in order to learn about it seems counter intuitive, but the lack of something can be telling. The problem is that it’s challenging to achieve zero gravity, so some playing with physics is required.

Each up/down flight pattern (parabola) gives researchers 25–30 seconds of zero gravity for their experiments. (Credit: Space Adventures, Inc.)

One option is a parabolic flight: an airplane follows the trajectory of a parabola, and beginning near the highest point of the arc, weightlessness is created for 25 to 30 seconds. This brief window of zero gravity is enough time to collect a great deal of data during experimentation. It’s that data that helps make it possible for researchers to determine if more extensive testing in low-Earth orbit will help mature those technologies.

Since 2010, Flight Opportunities has been partnering with universities and researchers to explore promising technologies in microgravity. The program accommodates different types of research through testing on various flight vehicles. In addition to parabolic flights, flights on suborbital reusable launch vehicles spend several minutes in space before returning to Earth. Vertical takeoff, vertical landing vehicles provide the ability to imitate the conditions of landing on other planets. And high-altitude balloons can take experiments and sensors as high as 120,000 feet without the use of expensive rockets.

Because space exploration is a multidisciplinary endeavor, the experiments the program supports are diverse. But the goal for all of them is the same—using iterative flights to test, refine and advance their development. For Massachusetts Institute of Technology (MIT) researchers, it only took two parabolic flights to make design improvements to their Multi-Orthogonal Jaunting rObot in Microgravity (a.k.a., MOJO-Micro).

MOJO’s parabola test included a demonstration of its ability to follow a path inside a lattice structure. (Credit: MIT Center for Bits and Atoms)

The tiny robot—three inches long and weighing 2.46 ounces—is designed to traverse and inspect three-dimensional, reversibly assembled discrete lattice structures.

Automated assembly and maintenance of large space structures is critical in NASA’s roadmap for space technology. In theory, MOJO could be added to lattice space structures of any size to perform autonomous health monitoring and inspections. In the lab, the mini robot had difficulty moving correctly. Benjamin Jenett, research assistant with MIT’s Center for Bits and Atoms, and his team thought gravity was the problem.

“We hypothesized that in a microgravity environment, locomotion in any direction would be relatively similar. This proved to be true,” he says. “We were able to perform additional experiments on path planning and motion optimization with the potential to reduce power consumption.”

A design failure was also identified, so new robots are being programmed with the ability “to adjust themselves to allow for error correction,” making them more robust and reliable, according to Jenett.

Whether success or failure occurs during a flight, researchers have the opportunity to modify their procedures and equipment for another parabola. A single flight can have up to 30 parabolas, accommodating a lot of tinkering.

For Northwestern University Ph.D. student and principal investigator Kristen Scotti, the first two parabolic flights gave her team time to review the results of each of their freeze casting experiments. Freeze casting is a process that creates highly porous materials, such as ceramic tile.

Scotti’s team suspended titanium dioxide in water and froze it in zero gravity. By changing the mix of water and suspension on the fly, they produced multiple samples. The goal was to compare materials made with standard manufacturing techniques against those made in the absence of gravity to see if that made a difference. It did.

“Just learning that it’s better in microgravity doesn’t help us, because it’s not like we can make these materials in microgravity all the time,” says Scotti. “We’re doing this to the process on Earth to get better results by understanding the role of gravity.”

The data gathered from multiple parabolic flights dramatically improved the technology readiness level (TRL) of the freeze casting experiments. TRL is NASA’s measurement system to assess the maturity level of a particular technology. Each proposed project is evaluated and assigned a rating.

An experiment’s technology readiness level (TRL) determines suitability for various types of flight environments, including suborbital flights through NASA’s Flight Opportunities program. (Credit: NASA)

Scotti credits the Flight Opportunities program with making it possible for her team to meet the microgravity justification requirements to qualify for further testing in space using small satellites known as CubeSats.

“The CubeSat mission allows us to run a lot of experiments over and over and over again. We’re getting temperature data and image data, which is going to tell us a lot about the solidification process,” she says. Her team is also preparing experiments that will be sent to the Space Station. Getting back six or seven space-manufactured samples to examine in the lab will contribute to the team’s knowledge and analysis.

Researchers Robert Ferl and Anna-Lisa Paul (see Insight) at the University of Florida in Gainesville have already had zero-gravity research samples sent back to them from the Space Station. Ferl, a professor focused on space biology, says collaborating with NASA on parabolic flights has expanded the research portfolio of the university’s Space Plants Lab team.

“As biologists, we fundamentally seek an understanding of what happens to biology as it leaves Earth’s surface,” he says. “How does biology respond to spaceflight environments? Therefore, we saw and continue to see Flight Opportunities as a mechanism to develop science capacity to answer that question.”

As a result, Ferl and Paul have expanded the scope of their research to include experiments during the transition from 1 g to weightlessness. Over time, their team has conducted experiments on 14 parabolic flights and a suborbital flight (on an Antarctic high-altitude balloon) and sent 10 orbital experiments to the Space Station.

Pictures from the university’s parabolic flights show just how fun they can be, including counting the number of parabolas flown. Ferl is up to 1,800. But their results, and those of other research teams, mean the Flight Operations program is accomplishing the serious business of advancing the operational readiness of innovative space technologies for lunar exploration and beyond. Some of the notable results from the 100 payloads tested across various platforms include space manufacturing with 3D printing; highly adhesive, gecko-like grippers to help with handling objects in space; and improvements in computing to withstand the radiation of space.