Video from the International Space Station shows Ex-Alta 1 being deployed.
(Edmonton) Alberta’s first satellite went into orbit early May 26, bringing the province and the University of Alberta into space for the first time.
Ex-Alta 1, the small cube satellite designed and built by University of Alberta students, was shuttled to the International Space Station aboard a rocket April 18. Astronauts aboard the ISS deployed the satellite this morning at 2:55 a.m.
Members of the U of A AlbertaSat student team gathered at the U of A Observatory to watch a live webcast of their spacecraft being shipped off into space.
“I would not have missed this for the world,” said Ian Mann, a physics professor whose research focuses on space weather. About 15 minutes after Ex-Alta 1 was deployed, Mann and the students stood at the U of A Observatory to watch the ISS fly overhead. Although not visible, Ex-Alta 1 was closely training the space station.
“It’s just after 3 a.m., the space station is in sunlight, we are in darkness, and we see the glint of light off of its solar panels and we knew that in almost the same place was a satellite flying over the city of Edmonton—where it was built,” said Mann. “It was a bit of an emotional moment.”
For ground control team member Dustin Nault, the deployment means he and fellow mechanical engineering student Tyler Hrynyk will be working nights, communicating with the satellite as it passes overhead.
“We had a nice moment, but now the payoff work begins,” Nault said.
Fishing line and heat elements: how a satellite unpacks
The cube satellite, which is roughly the size of a shoe box, is part of an international cube satellite mission called QB50. Ex-Alta 1 will be working with 38 other satellites built at universities around the world in a mission to study the lower thermosphere and space weather—those powerful bursts of solar wind that represent a threat to trillions of dollars worth of electrical power and communications infrastructure here on Earth.
Once released from the ISS, a cascade of events occurs aboard Ex-Alta 1: Six switches on the satellite open as soon as it leaves the space station, allowing electrical current to flow to the satellite’s systems. With the charge running, the first thing that happens is that nothing happens: a timer is set for 30 minutes so the satellite can get some distance from the ISS before it begins to operate. If it is released in sunshine, solar panels will begin collecting energy.
After 30 minutes, another timer is set, preventing the radio from turning on for 40 minutes. This gives Ex-Alta 1 time to complete a set of tasks in an orderly manner. First, a digital fluxgate magnetometer designed by David Miles, an instrument engineer at the U of A Department of Physics, will begin recording data about the magnetic field around it, while still stowed in the satellite. The magnetometer is attached to a long, spring-loaded boom arm folded tightly along the length of Ex-Alta 1, held in place with a strand of ordinary fishing line.
Soon after, a heat element will burn the fishing line and the boom arm will unfold. With the arm extended, the magnetometer is far enough from the satellite that Ex-Alta 1’s magnetic field doesn’t interfere with its measurements.
Next, heat elements burn through fishing line to release four communications antennae, similarly folded against the satellite’s body. After that, four more strands of fishing line at the front face of Ex-Alta 1 are burned, releasing Langmuir probe needles, which measure plasma electron density.
“We need to talk.” Ground Control takes over.
In theory, this chain of events will take 70 minutes and Ex-Alta 1 will begin transmitting a beacon on its own individual frequency. Nineteen hours and nine minutes after entering orbit, at 11:04 p.m. MST, Ex-Alta 1 will rise above the horizon low in the southwest. It is likely that by this time, the NORAD Joint Space Operations Center will have identified and registered Ex-Alta 1 in its catalogue of orbiting spacecraft and devices.
From a control room in the Centennial Centre for Interdisciplinary Science, mechanical engineering undergraduate students Tyler Hrynyk and Dustin Nault will lock onto Ex-Alta’s signal and send a message inquiring about its status. The team will determine whether the power is on, if the voltages are right, whether the components are communicating with one another.
“We’ll listen for its beacon signal, verify that it’s alive, and verify its own telemetry so that we can track it individually,” says Hrynyk.
The reality may be quite different. Getting to the point of even verifying Ex-Alta’s signal could take a full week, and could involve assistance from AlbertaSat’s compatriots in the QB50 mission. Several of the teams have already deployed their satellites and some are having difficulty communicating with them—the AlbertaSat team says each university team will support others.
“We’ve met a lot of these people at conferences,” said Hrynyk. “We’re all friends. It’s international collaboration.”
Regardless of the time it takes to confirm that its systems are running properly, the next step, stabilizing the satellite, is important and time consuming. Ex-Alta 1’s attitude determination and control system stabilizes the spacecraft using magnetorquers (leveraging magnetic forces), Sun sensors and Sun-Earth cameras (to help it understand its orientation), and a magnetometer to lock its spin into one axis. After that, a momentum wheel begins turning against the satellite’s spin, eventually manoeuvring it into a stable orientation.
TALE OF THE TAPE
Physically, Ex-Alta 1 is the largest satellite in the QB50 mission, measuring 30 x 10 x 10 cm and tilting the scales at 2.64 kg. It will orbit the Earth at an altitude of 415 km for up to 18 months before burning up on re-entry.
Ex-Alta 1 is carrying four payloads:
• A Multi-Needle Langmuir Probe that is part of the QB50 Mission to study space weather, precisely measuring electron density
• The Digital Fluxgate Magnetometer designed by David Miles, an instrument engineer at the U of A Department of Physics, which accurately measures magnetic signatures in space weather
• A Radiation Dosimeter, which enables routine radiation monitoring of the spacecraft
• Athena: an open-source, onboard computer for cubesats, designed and built at the U of A, which is being demonstrated for use in future space missions
Its power storage is four Li-ion batteries—heated to prevent freezing—that provide a reserve capacity of 38.5 Wh. Nine solar panels, each with two photovoltaic cells with 28.3 per cent efficiency, generate power with a peak output of 1.23 W per cell.
Ex-Alta 1’s radio transceiver provides full duplex communication with the satellite on the 70-cm UHF band. The downlink rate is 9,600 baud with a radiated power of 1 W.