SASKATOON KEY TO COMET PROJECT
13 Nov 2014
SASKATOON KEY TO COMET PROJECT
Historic space probe calls home on locally-made dish
When the Rosetta deep space probe bleeped back to Earth confirming a lander was sitting on a comet for the first time in history, a Saskatoonbuilt dish took the call.
Sixteen years after winning a lucrative contract with the European Space Agency, Saskatoon’s SED Systems’ creations played a pivotal role Wednesday when the unmanned Philae lander plopped onto the icy surface of the comet 67P/ Churyumov-Gerasimenko.
The agency hopes onboard instruments will gather data to explain the origin of celestial bodies, and possibly life on earth.
“We were very happy for our customers,” said Denis Sirois, a business manager with SED. “It takes an awful lot of analysis and planning to do this kind of thing.”
The telecommunications company, which makes its home at Innovation Place, designed, tested, and constructed three 35-metre wide satellite dishes in Australia, Spain and Argentina to communicate with the unmanned Rosetta probe and its dishwasher-sized lander. Each dish took at least three years to design, build and calibrate, Sirois said.
The ESA paid between $80 million and $100 million for all three.
Each massive dish weighs about 500 tonnes and is as tall as a six-storey building, Sirois said.
Like a commercial satellite dish “on steroids,” the ESA dishes need to be massive, and movable in every direction to capture Rosetta’s weak signals from as far as a billion kilometres away, he said.
A powerful transmitter allows the ESA to send commands to Rosetta.
The demanding specifications call for “extreme” designs, such as cryogenically cooled receivers, to minimize interference from electronics on the ground, Sirois said.
“That’s what’s exciting about this for our engineers. Very few people get a chance to build these kinds of things.”
Some smaller components were built in Saskatoon, and most of the system parts were tested in the Prairie city. Subcontractors were hired for dish construction. SED Systems began as the Space Engineering Division at the University of Saskatchewan in 1965. It later became a private company and started in the satellite business, launching small payloads into the lower atmosphere.
Now owned by Ontario-based Calion Ltd., SED does mostly telecommunications work, picking up contracts with satellite management systems and satellite radio networks.
The ESA can use the transmitters and receivers for other deep space projects — not just Rosetta.
A decade after launch, Rosetta, Philae, and comet 67P are now hurtling toward the sun at 66,000 kilometres per hour.
After slingshotting itself around Earth and Mars, Rosetta met up with the comet in August, somewhere between the orbits of Mars and Jupiter.
ESA controllers endured a tense seven-hour wait Wednesday after Rosetta released the lander and watched, powerlessly, while it gravitated toward the comet.
They clapped and embraced at mission control in Darmstadt, Germany as they got confirmation Philae was on the surface, despite technical problems.
The head of the lander operation said Philae may have bounced once before coming to rest.
Stephan Ulamec told reporters in Darmstadt that data received from the Philae lander indicates it lifted off from the comet, turned slightly and then landed again.
Philae managed to stick the landing despite its thrusters failing to deploy and problems with its harpoons, which were meant to anchor it to the comet’s icy surface. The lander’s feet are also equipped with screws to drill itself into the comet.
One thing scientists are keen to avoid is having the lander drift off into space in the comet’s lowgravity environment.
“The biggest problem of success is that it looks easy,” Jean-Jacques Dorain, director of the ESA, said after the lander touched down.
Scientists have likened the trillion or so comets in our solar system to time capsules that are virtually unchanged since the earliest moments of the universe.
Philae’s instruments include devices to measure light, electrical magnetism and heat. The lander will also drill below the surface of the comet to extract a sample that will be analyzed on board and it will provide plenty of images of a world no human has ever seen close up.
The lander’s batteries are expected to last just 64 hours, but that should be enough for scientists to gather a wealth of data. In addition, the lander has a solar panel that should be able to provide an hour’s worth of battery life each day.
The real question is how Philae will cope with the comet’s activity. As 67P approaches the sun, the amount of matter it releases will greatly increase, posing a potential risk to the lander and even Rosetta.
As the comet reaches perihelion, the closest point to the sun, the rising temperature could also damage Philae. The lander should remain stuck to the comet forever, even after its systems have shut down.