A pressure-packed recovery mission in the harshness of space featuring the ingenuity of the University of Alberta's satellite team and a race against time played out high above Edmonton on Jan. 19, sending notice that the future of Canada's designs on exploration of space is in good hands.
The saga began in November as DESCENT, a satellite mission designed and made at York University, was set to launch from the International Space Station.
The mission consists of two cube satellites, or CubeSats—each smaller than a loaf of bread—that, when deployed, are connected by a 100-metre long tether. The main purpose of the mission is to study how to mitigate space junk in orbit.
Charles Nokes, who earned a BSc from the Faculty of Engineering in 2016 and an MSc from the Faculty of Science in 2019, and is a project co-ordinator with AlbertaSat—the U of A student-based satellite design team—received word that York suddenly found themselves with no way to talk to their CubeSat, which was on the verge of being deployed.
Nokes, who helped lead AlbertaSat's Ex-Alta 1 CubeSat mission in 2017 under the guidance of faculty supervisor Ian Mann, explained that because of the lockdown, York had not completed their ground station before the launch.
They had been using the ground equipment during testing but had not been able to integrate a piece of equipment for cutting through the torrent of radio frequency interference found in busy metropolitan centres, like Toronto.
The York team would end up solving this communication problem by transmitting to the satellite from the university and listening for the satellite's responses using an antenna at the rural Ontario home of one of their professors.
They operated successfully like this for a few weeks after launch, but then suffered a second setback just before the Christmas break—the radio used to transmit to the spacecraft suffered a failure, and again, because of the lockdown, there was no fix in sight.
Answering the call
"We needed a working ground station, and the Alberta team answered our call," said Franz Newland, a faculty adviser with York's satellite team.
Nokes explained that communicating with a satellite in low Earth orbit is always a concern as spacecraft in this orbit travel around Earth at about seven kilometres per second, which amounts to 16 trips around the globe daily.
"Relative to us on the ground, these CubeSats are really moving," he said. "We can only talk to them for eight to 10 minutes as they fly overhead."
However, without a functioning ground station, the speed at which they travel is moot.
"Without communications, the success of the mission looked in doubt," said Nokes.
Mission DESCENT had suddenly taken a turn toward Mission Impossible. Not only was communication lost, but it turns out self-destruct timers are not just a trademarked cliche of Tom Cruise thrillers, they're also an element of CubeSat design.
"If after a certain period of time, the satellite doesn't receive any kind of communication from the ground, the York team designed their CubeSat to deploy the 100-metre-long tether to demonstrate the accelerated deorbit using the electrodynamic tether technology as part of the mission," said Nokes, adding the deorbit means that the satellite is vaporized upon re-entry into Earth's atmosphere.
Race against time
Faced with losing the bulk of the mission, York asked the AlbertaSat team whether they could try contacting DESCENT.
"We frantically started trying to piece our ground station back together and update it, because, as it turned out, in support of the next U of A satellite mission our students had completely dismantled the ground station to do some testing for our new satellite," said Nokes.
For that, the team called up AlbertaSat alumnus Collin Cupido, who graduated with a BSc in astrophysics in 2014, and local radio amateur J.T. Mitchell, who helped install the antenna located on top of the U of A's Electrical and Computer Engineering Research Facility, to modernize the ground station and ensure it was functional.
The next step was the less dramatic but encouragingly supportive process of getting the proper permissions from Innovation, Science and Economic Development Canada.
"They turned it around in hours, sent us the licence to send these messages and said, 'You're good to go.'"
Next up: figuring out how to speak to this particular satellite.
"It turns out this satellite only speaks when spoken to, and you need to talk to it with a very specific introductory line," said Nokes. "Basically we just had to learn how to speak its language.
"We wrote the message as correctly as we knew how and at that point we were thinking, 'If this doesn't work, we don't know what will.'"
On Jan. 19, with less than nine days left on the clock, the U of A hailed DESCENT.
Radio silence.
Not unexpected given the speed and the precise nature of the mission. Nokes said of the 16 times the satellite orbits Earth in a day, it will usually pass over Edmonton four to five times, so they tried again 90 minutes later.
"It worked," said Nokes.
In fact, he said that first successful pass was the first time information had been pulled out of the signal, allowing York to see that the spacecraft was working, and understand what it was saying.
There were some additional incompatibility issues that needed ironing out—including linking the ground station at the U of A through the internet so York could talk directly with their satellite, save for a speed-of-light pit stop in Edmonton—but all has unfolded as planned.
Exciting experience
Fourth-year engineering physics student Jayke Boghean, who joined AlbertaSat two years ago and hadn't had any hands-on CubeSat excitement in his short tenure before the rescue, said there was a steep learning curve, but he was fortunate to get an opportunity normally reserved for the time after the satellite you are building is launched.
"Ensuring the success of York's mission while getting experience in satellite operations for our future mission was a win-win—and makes for a great story, of course," he said.
"This is just an example of the collaboration that's going on right now between new space-faring universities in Canada. We are always just sharing information and helping each other out."
Nokes added this level of co-operation has become commonplace with this new access to space.
"Space is so hard. Building something that's going to work in space, that's going to survive in space, is hard. So it just doesn't make sense not to help."
This collaborative spirit is what guided the success of Ex-Alta 1, the U of A CubeSat designed to measure space weather as part of an international mission featuring 50 teams from around the world.
Nokes said the Canadian Space Agency saw the U of A's success on that project and decided to support a pan-Canadian version, the Canadian CubeSat Project which includes support for the next U of A satellite, Ex-Alta 2—designed to help fight wildfires—as well as a constellation of satellites called Northern SPIRIT, which the U of A is building with partners at Yukon University and Aurora College in the Northwest Territories.
"There's now a team in every province and territory building a cube satellite to launch in the next one to two years," said Nokes. "There's just this big collegial connection."
George Zhu, a York faculty adviser for their satellite team, said the actions of the U of A team were critical not only for the success of DESCENT, but also for all future Canadian space missions.
"The current success shows the importance of collaboration in satellite communication among university teams," said Zhu. "It could be viewed as a precursor of the current Canadian CubeSat Project, where the teams could collaborate on satellite communication with existing university ground stations instead of building a ground station for every team."
