By Lily Williams
Imagine NASA in action. A rocket, pushing off a landing base and away into the skies with titanic force, smoke and fire. An image of Earth, floating serene in the dark blanket of space. Tunnels and pipes and computers. Millions of wires zipping every which way. Lights blinking, code flying and scientists monitoring everything with meticulous precision.
What you might not imagine is a Northwestern University undergraduate, eating a grilled cheese and going over satellite instrument designs at a dining hall on campus.
But a group of NU students are at the heart of a NASA mission that will be launching a small satellite and research instruments into orbit this summer. The satellite, under construction at the University of Illinois at Urbana-Champaign, will house an NU device that freezes solutions and then thaws them, leaving behind a casting of materials.
The instrumentation will take photographs and send data back to Earth to document the whole process. This is SpaceICE: Interface Convective Effects, which separates substances in solutions from the water in ice. The process is giving us clues to a new method of fabrication that could be used to make many different materials, from fuel cells to cocoa tablets, both here and in space.
Northwestern materials science professor David Dunand came to the university in 1997, after receiving his Ph.D. from MIT in materials science and engineering. He took up research on metallic alloys, foams and ceramics. Hence, it was no insignificant matter when the Swiss native lauded a SpaceICE presentation his students gave to NASA last week. The SpaceICE/NASA collaboration is about a year old. The presentation is one of the last that the handful of students involved in the project will give.
“Fantastic, really well done. I am impressed. That was extremely professional. I am feeling really good with where the project is. And fame… The dean of course is aware of it – you can expect quite a bit of visibility,” Dunand said after the group’s design meeting.
The students are working to build the small SpaceICE device, about the size of a breadbox, that NASA will launch in the UIUC satellite so that the Northwestern team can conduct experiments. The device is made of three chambers containing miniscule silver-coated glass particles suspended in water.
At the team’s command from Earth, the suspension will freeze and thaw, the silver-coated glass particles separating into microscopically porous structures left in the melting channels of ice. The team will photograph the structures to determine how the lack of gravity will affect this process, given that the cyclical process of convection – where dense cold water sinks and light warm water rises – doesn’t occur without gravity.
Dunand wasn’t the only one excited by last week’s presentation. NASA also seemed very satisfied with SpaceICE’s design so far. “I wanted to give you guys kudos for having an excellent functional diagram and also the programming plan for how you’re making decisions and the logic for the experiment… those were excellent representations of what you guys were doing,” said David Wilcox, who oversees the implementation of awards on behalf of the NASA Science Mission Directorate and Office of Education.
The project is intricate and any concerns that arise need to pass through not just Dunand’s lab, but also through the team of professionals monitoring the project on NASA’s end. And concerns regularly arise, as is the case with any novel engineering.
“Our greatest risk we think is the O-ring. We’ll need to test it through freeze-thaw cycles,” said Andy McIntosh, one of the student system designers on the project. The O-ring is a dynamic seal between the heating element of the device and the chambers filled with suspension. Repetitive freezing and thawing could wear out a poorly designed O-ring and ruin the device.
“We’re also worried about vibrations during launch,” said McIntosh. After all, the device will be sent into space launched on a real live rocket.
The students are loosely divided into three teams to deal with the multiple aspects of building and monitoring the cube-shaped satellite (CubeSat) and instrumentation: engineering, science, and programming and electronics. Perhaps one of the most significant part of the project? The students are all undergraduates.
Krysti Scotti, an NU undergrad who will soon advance to a Ph.D. candidate studying with Dunand, is really the one managing all the project work hands-on. Scotti decided to return to school at age 30, taking night classes at a community college while also working full-time. In her first semester, she did a short internship at NASA’s Marshall Space Flight Center and began materials science research. In 2012, she quit her job and made the transfer to NU where she began to study with Dunand. A snag in her combustion synthesis of materials prompted him to recommend something called freeze-casting.
It worked out “beautifully. We did three flight campaigns (a total of 10 flights) on microgravity freeze-casting through NASA’s Flight Opportunities Program. We published a paper on this work,” said Scotti.
Scotti could pass as a typical undergrad – she’s energetic, friendly and positive. She’s also authoritative in a way that isn’t bossy or intimidating. She works with her SpaceICE teammates as well as directing them, and admits when she doesn’t understand something.
“I know Python (a coding language) fairly well, not to the point where you won’t be revising my code,” Scotti says to one of the teammates, Yingda Hu, one of two programmers on the project.
The SpaceICE project falls within NASA’s Undergraduate Student Instrumentation Project (USIP). Forty-seven undergraduate groups received grants – totaling over $8 million – to do flight research. The name of NU’s group comes from the concept of freeze-casting, in which particles suspended in water form a structure when water expands upon freezing. The water then sublimates (turns directly from solid to gas) and a porous particulate structure remains behind.
NASA initially discovered freeze-casting in 1954. They mixed particles with water, froze them in a freezer, then heated the solution to high temperatures to sublimate the ice and bond the particles. The process was largely forgotten until the early 2000s when researchers started freezing under a thermal gradient, causing the ice to freeze in different spots instead of all at once and allowing more control of the structures remaining after sublimation.
The SpaceICE team will study this freeze-casting process in space by freezing and melting, rather than sublimating, because they are most concerned with the solidification of the ice and the silver-coated glass structures that form. To understand how the process occurs without gravity, they will conduct parallel experiments on Earth, hoping to improve terrestrial fabrication methods and comparisons.
UIUC’s critical design for CubeSat means making a high-tech box that will surround NU’s device. NU’s role in the project diminishes in the next month or two, as members of SpaceICE graduate and go to work full-time for NASA, or the Navy, or for engineering firms in Kansas. A large proportion of the team is made up of seniors.
UIUC is responsible for operating CubeSat once it’s in space, including any experiments the team wants to run, data coming back in from space and communications sent to and from the CubeSat. SpaceICE will then analyze the data as it returns to Earth.
“Basically, without UIUC, we have nothing – no way to put our payload into space, no housing to protect it, no power, no communication,” said Scotti.
The next step is another design review with NASA in about a month. The design meetings are quiet, formal and intense. On Monday, in a preparatory meeting with the SpaceICE team, Scotti tried to calm the jitters. “Yes, this is design review and we want to show that we’re all together, but we also want to know what issues there are.”
Some of the group’s concerns include a contingency plan for a failure of one of the solution chambers in their device as well as having enough battery power to run experiments for the three months the satellite is in orbit.
At last week’s design review, USIP was also curious as to the level of testing of the prototype (which the team hasn’t fully created yet) as well as an overall thermal analysis on how the entire spacecraft system may affect the CubeSat. “Take a little bit to process and we’ll meet in a couple of days. We’ve got a whole lot to do. A whole lot,” Scotti said afterward.
SpaceICE will deliver the device to UIUC at the end of the summer, at which time they will start integration and testing into the CubeSat. That will take about 4-5 months before delivery to NASA. SpaceICE’s final readiness review with NASA is scheduled for May 2018 and the launch will occur sometime after that.
“This is the first NU CubeSat isn’t it? We are in good shape, but we have 4,5 weeks, so we are going to be in a rush,” said Dunand.
The NU team has one other small division: journalism. An embedded graduate journalist – me – will be following the team for the remainder of the quarter as they finish up their project. For my capstone, I’ll be producing stories, profiling the students, photographing and taking video of their creations, and editing audio clips of the day to day in order to bring their work to life, taking over for undergraduate Medill student Avendah Watson, who covered the team previously.