KENNEDY SPACE CENTER (FL) – From salad dressing to foam body wash, many everyday products could get an eco-friendly upgrade thanks to microgravity research. The City College of New York (CCNY) is launching an investigation to the International Space Station (ISS) on SpaceX’s 25th Commercial Resupply Services (CRS) mission to test more eco-friendly ways to create foam products (which consisted of gas bubbles dispersed in liquids or solids) and products made through emulsion (when tiny droplets of one liquid are dispersed in another fluid).
However, this is not the only investigation on SpaceX CRS-25 aiming to improve products used by millions of people worldwide. from Arizona State University and Rensselaer Polytechnic Institute (RPI) are leveraging the ISS National Laboratory to improve the mass production of pharmaceuticals like researchers vaccines. These investigations are funded by the US National Science Foundation (NSF) and seek to use the unique space environment to help answer scientific questions that have been challenging to address on the ground.
Using Microgravity to Manufacture Environmentally Friendly Foams and Emulsions
The investigation from CCNY has two parts: One aims to study whether it is possible to use eco-friendly nanoparticles instead of surfactants to stabilize foams and emulsions. Surfactants are chemical compounds that stabilize the interface between liquid and air or between two liquids that do not mix, such as oil and water. The other part of the project aims to address a 135-year-old question regarding the optimal packing structure of dry foams. It will look at how bubbles pack together at the most basic level. An optimal packing structure has been predicted for decades but has never been observed in free foams.
On the ISS, microfluidic devices will generate foams and emulsions, which the research team will analyze using an optical microscope in microgravity—an ideal environment for the experiment, said Jing Fan, an assistant professor in mechanical engineering at CCNY who is one of the investigators leading the project.
Microgravity is helpful because it will preserve the foams and emulsions over the several hours it takes to test whether nanoparticles can be used to stabilize them. On Earth, the effects of gravity cause foams and emulsions to break down and drain too quickly. Additionally, in the absence of gravity, the bubbles and droplets that make up dry foams can assemble without being confined in a container. This allows the researchers to study the most efficient packing structure for the foams.
“Hopefully, we can get some results that simply cannot be obtained on the ground,” Fan said. “This could help us find solutions to problems we have faced for decades when attempting to pack and stabilize foams and emulsions for commercial use.”
Paving a Path for Improved Vaccine and Pharmaceutical Manufacturing
Protein aggregation (clustering) is a significant limitation in pharmaceutical manufacturing that reduces the quality and yield of many medicines and vaccines. Researchers from Arizona State and RPI are using microgravity conditions on the ISS to address this problem. The research team will develop and test predictive models for understanding and controlling hydrodynamics (the forces acting on or exerted by fluids) that cause protein aggregation during drug development.
Once the investigation is on the ISS, the researchers will study the flow and aggregation of common proteins found in human blood. They will do this by spinning a one-inch-diameter droplet of protein solution in a motorized module and observing as it experiences what scientists call “shear,” meaning the force of two fluids sliding past each other. Using the motorized module in microgravity allows the researchers to study the actions of proteins in a containerless liquid system without solid walls. In this system, the protein solution behaves in a way that is more similar to proteins surrounded by soft tissue in the human body. This is because a film tends to form on the liquid surface of the drop, resulting in confinement of the drop that is more like soft tissue than rigid container walls.
Microgravity is needed because on Earth, such a large droplet of protein solution would break up due to gravitational instabilities. However, in the absence of gravity, the droplet remains stable, explained Juan Lopez, an applied mathematics professor at Arizona State who is one of the investigators leading the project. This will allow the research team to watch the droplet over several hours to determine what causes protein aggregation and develop predictive models.
“When we first engineered this novel experiment, there was the initial euphoria of just succeeding at getting it to work in microgravity,” Lopez said. “Now, we’re moving away from experiment design to get into the nitty-gritty of teasing out the science.”
Results could have widespread implications, as most of the vaccines we use today are protein-based. Lopez said it is essential to understand how shear affects proteins, which is always present in large-batch pharmaceutical production. Predicting the effects of shear could help researchers figure out what to do to mitigate undesirable results in pharmaceutical manufacturing.
These are just two of more than 15 ISS National Lab-sponsored payloads onboard SpaceX CRS-25, which is set to launch from Kennedy Space Center no earlier than July 14 at 8:44 pm EDT. Please visit our mission overview page to learn more about all ISS National Lab-sponsored research on SpaceX CRS-25.