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Students at Stanford Engineering are about to start building and testing miniature satellites without leaving their homes.
Because COVID-19 continues to keep most students off campus, Stanford is shipping free satellite kits to some 30 students of astronautical engineering. Their assignment: Build, program and test their own CubeSats, spacecraft that are about the size of a Rubik’s Cube (10 x 10 x 10cm).
The move highlights the intersection of two big trends: the plunging cost of technology and rapid advances in tiny, self-navigating satellites that can be deployed in swarms for tasks like monitoring space weather, looking for distant planets or studying the sun with unprecedented capability.
Marcus Murbach, a NASA engineer at Ames Research Center who will be the lead instructor, says that remarkable improvements in manufacturing, miniaturization and electronic design have opened the door to space exploration for researchers with small budgets. As a result, Murbach says, “It’s very important to give students the hands-on skills to develop rapid prototypes of flight hardware.”
The satellite kits cost about $500 each and come with an array of programmable chips to handle navigation, communications, processing and data collection, as well as a ground station that serves as mission control.
The kits will go to students in two courses in spacecraft design that begin in the winter quarter – AA 136, for undergraduates, and AA 236, for graduate students. The components can be connected without any soldering or wiring, almost like snapping together Lego pieces. To make them actually perform, however, students will have to program them to carry out specific maneuvers and tasks in low-Earth orbit.
Sonia Travaglini, skilling and learning specialist in the Department of Aeronautics and Astronautics, says the kits help students engage in experiential learning at home and contain everything they need to safely tinker at their kitchen tables. “The kits allow students to put real-world aerospace engineering skills into practice wherever they are in the world – and also have fun,” says Travaglini, who has focused on ensuring safety and equitable access for students from all economic backgrounds.
The students will have the chance to understand how satellites work through educational kits that can be later expanded in terms of computational, actuation and sensing capability to accomplish a real mission in space. In addition, the students will learn state-of-the art techniques and apply them to current exploration problems.
The satellite kits don’t come with propulsion systems or solar panels, which would be needed for actual space flight but are expensive. Instead, students will be building table-top models and testing them here on Earth for their space readiness. That will require grappling with practical problems in orbital mechanics, attitude determination, long-distance communications and even coordination between satellites.
Among other things, the CubeSats must be able to orient themselves in space and calculate velocity, acceleration and trajectory. They must also store and analyze sensor data on temperature and ultraviolet radiation, and eventually knit themselves into a relay-style communications network.
“Spacecraft design is very multidisciplinary,” says Simone D’Amico, associate professor of aeronautics and astronautics and founding director of Stanford’s Space Rendezvous Laboratory. D’Amico is advising on the course curriculum. “You have mission control and several on-board subsystems, including those for navigation, communications, power and thermal control. You have to embed software in tightly constrained microprocessors to get the hardware to carry out instructions autonomously.”
One practical problem students will face, for example, is how to stop a satellite from spinning and tumbling chaotically after it’s flung from a launch vehicle. Students will have to weigh different mechanical strategies and algorithms, and then test them in a suitably out-of-control situation. That could mean putting their table-top satellite inside a ball and rolling it across the floor or down a rocky hill. The students will then have to load their algorithms and other programming onto the chips that come with their kits.
Communications will present other design issues. The satellite kits come with devices that transmit data over long distances using frequencies reserved for industrial and scientific purposes. It’s the same technology that increasingly links the Internet of Things, but these devices aren’t plug-and-play. Students will have to optimize their limited power and bandwidth. They will also be asked to figure out how to turn satellites into the relay nodes in an orbiting communication network.
“It’s a way of mimicking the complexity of global communications,” says D’Amico. “The idea is to establish coordination between the students, even though they are each alone in their own rooms, by having CubeSats act as relays in an orbiting network.”