Scientific ideas are everywhere. Some of the greatest discoveries come from tinkering and playing with new concepts and ideas. NASA astronaut Don Pettit is no stranger to invention and discovery. During his previous missions, Pettit contributed to the advancement of human space exploration aboard the International Space Station, resulting in several published scientific papers and breakthroughs.

Pettit, accompanied by cosmonauts Alexei Ovchinin and Ivan Wagner, will blast off to the orbiting laboratory in September 2024. As he prepares for his fourth spaceflight, read about previous “science of possibility” experiments that Pettit has conducted in his spare time using materials readily available to the crew or in his personal kit.

Freezing ice in space

Have you ever noticed a white bubble inside the ice in your ice cube tray at home? That’s trapped air that collects in one place due to gravity. Pettit used that knowledge, access to a -90° Celsius freezer aboard the space station, and a weekend of open space to learn how water freezes in microgravity compared to Earth. This image uses polarized light to show the thin frozen water and the visible differences from the ice we typically freeze here on Earth, providing greater insight into physics concepts in microgravity.

Space Mug

Microgravity affects even the most mundane activities, such as sipping morning tea. Crews typically drink their beverages from a specially sealed bag with a straw. Using overhead projector film, Pettit invented a prototype of the Capillary Beverage, the Space Cup. The cup uses surface tension, wetting, and the shape of the container to mimic the role of gravity in drinking on Earth, making it easier to drink in space and showing how discoveries aboard the station can be used to design new systems.

Planet formation

Using materials that break down into very small particles, such as table salt, sugar, and coffee, Pettit experimented to understand planet formation. A key early step in planet formation is the aggregation, or clumping, of tiny particles, but scientists don’t fully understand the process. Pettit placed different mixtures of particles in plastic bags, filled them with air, shook the bags vigorously, and observed that the particles clung together within seconds due to what appears to be an electrostatic process. Studying the behavior of tiny particles in microgravity can provide valuable insight into how material composition, density, and turbulence play a role in planet formation.

Orbital motion

Knitting needles made of various materials arrived on the station as personal items for the crew. Pettit electrically charged the needles by rubbing each one with paper. He then released the charged water from a Teflon syringe and watched the water droplets orbit the needle, demonstrating electrostatic orbits in microgravity. The study was later repeated in a simulation that included atmospheric drag, and the 3D motion closely matched the orbits observed during the demonstration on the space station. These observations could be analogous to the behavior of charged particles in Earth’s magnetic field and prove useful in designing future spacecraft systems.

Astrophotography

An innovative photographer, Pettit used slow shutter speeds, multiple cameras, infrared and other techniques to create breathtaking images of Earth and star trails from the unique perspective of the space station. These images contribute to the database that scientists use to understand Earth’s changing landscapes, and these images can inspire public interest in human spaceflight.