Warning: this article contains the mention of astronaut ice cream, a matrix and a lot of science. Proceed at your own risk.
Space Ice, a team of researchers from McCormick's Dunand Research Group, is dedicated to manufacturing products for space as well as perfecting manufacturing techniques for astronauts, recently obtained a grant from NASA for collaboration with University of Illinois Urbana Champaign and Bradley University. The grant will be used for the study of freeze-casting, a common technique for creating materials in outer space, to make pretty much anything ranging from cocoa tablets to fuel cells.
The project is sponsored through NASA’s Office of Education, whose goals was to have undergraduate students work on science that is relevant to NASA while providing a platform to train students in the real world.
The project consists of a collaboration between the three universities, with three different subteams: an engineering team, a science team and a journalism team, which is in charge of spreading the word of the project’s progression. At Northwestern, students from McCormick, Medill and Weinberg have the opportunity to collaborate on the project.
“I think it’s going to be really beneficial to the science students and the journalism students in that [they] get a behind scenes tour of the sciences and the scientific process, and [they] are also going to help the science students to put things in language that is easy to understand for the general public,” Weinberg senior Kristen Scotti, the project team leader, said. “So we are super excited about the interdisciplinary nature of it.”
According to Medill sophomore Avendah Watson, the leader of the journalism team, “It helps to have that interdisciplinary element so that scientists who talk in their science-y ways, with a lot of jargon, things that most people don’t really understand, make sure that they can communicate their ideas in a personal way.”
“There is a lot of learning involved, especially as a journalism major,” she added. “I don’t know if I’ll ever take a science class again, but it something beautiful to be able to look at something that complex and put it into these words that people can understand.”
Space Ice has been working with freeze-casting in microgravity, a state of very weak gravity, much like outer space for about three years now.
Freeze-casting is the process of taking suspension particles – particles that basically just stay where they are in water – and putting them in a mold. The mold is then placed on an extremely cold surface, so that ice particles rise from the bottom and start pushing the particles that are in suspension.
What does this look like? Imagine putting your hand on a pin impression board, and as you push your hand inward, the metal pins push outward in the shape of your hand. Now imagine those metal pins are actually ice particles, rising from your hand (or, in technical terms, from the cold of the surface the mold was placed on).
As the ice continues to grow, the particles will accumulate in the region ahead of the ice front and start to settle in between the ice. Going back to the pin impression board, imagine that a bag of small balls are dropped onto the raised surface, those particles would then settle between the crests of the pin structure, much like the particles in the mold would settle between the ice.
Once the mold is frozen all the way, it gets dehydrated by being placed into a freezer dryer – think astronaut ice cream. This takes takes out the ice and leaves a fragile particle matrix.
Finally, the matrix is put into a furnace, or oven, to bake so that the particles bind together, leaving behind a more solid material, which could be electrodes, structural materials, or even snacks.This freeze-casting technique can be used to make everything from food, to pharmaceuticals, to functional materials such as filters.
However, for each of those applications, one would need a different microstructure. In other words, each application requires a different shape of the pores in which the ice goes through, with a different organization.
There are many different factors that go into the shapes of the microstructure, including gravity induced convection (i.e. fluid motion), and temperature difference throughout the mold sample.
In order to get rid of these complications, freeze-casting is done in microgravity. That way, all those factors are shut off, and scientists can study the process behind freeze-casting.
Therefore, astronauts can use freeze-casting up in space to make pretty much anything they need. It is also sustainable in that the materials necessary can be used multiple times.
“This is a really great technique to use for space manufacturing because when you take the ice out, you’re not consuming it, you’re just collecting it so you can do it again, and again, and again, and it doesn’t require any machinery,” Scotti said.
Space Ice received funding by NASA a few weeks ago. They will be having a kickoff meeting in a few weeks with UIUC and Bradley University to get all the team members on board with the timeline of the project. The teams will begin working this summer.
The researchers will be spending the next several months building an experiment with freeze-casting in microgravity, building a satellite, and integrating the experiment and satellite together. Afterwards, the satellite will be launched into low Earth orbit, where the International Space Station operates. They will spend six months gathering data from their experiments, which they can control through several communication windows from here on Earth.
Editor's note: this story has been updated at 2:06 p.m. to include Kristen Scotti and Avendah Watson's years and schools within Northwestern.
This story has been updated on May 22 to reflect the fact that the University of Illinois Urbana Champaign, not the University of Illinois Chicago, are partnering with Northwestern. Bradley University is also partnering in the project.