As Canadians bump up their involvement in space-based earth observation, one of the pressing problems looming is how to deorbit those satellites once their missions are completed. This was one of the themes of the Earth Observation track at this past weekends Canadian Space Summit.
NASA currently tracks 19,000 objects that are 10 centimetres or more – a number that has accumulated in just 53 years of space exploration. The Canadian Space Summit’s earth observation track focused on a number of nanosatellite missions that Canadians are either creating, or co-involved with.
Even these small satellites – sometimes barely the size of a kitchen chair – are subject to ever-more-stringent regulation, one researcher told the group of space professionals attending at Ottawa’s Lord Elgin Hotel, just steps from the National War Memorial, on Sunday.
“(The issue) is slowly sneaking up on all the missions that I’m dealing with,” said Grant Bonin, a researcher at the very active University of Toronto Institute for Aerospace Studies (UTIAS), which has about 15 ongoing missions.
“It’s very challenging in 700 kilometre-altitude, where most nanosatellites operate. They just won’t come down on their own.”
Perhaps UTIAS’ best-known mission is Nanosatellite Tracking of Ships, a joint mission with Cambridge, Ontario’s COM DEV that filters out the automatic identification signals that ships must broadcast while in port or in transit.
The signals give information such as nationality, destination and the type of cargo on board. Most famously, COM DEV used the technology to do security for both the 2010 Olympics and FIFA World Cup.
“This went from a design sketch to a mission in seven months, and we are very proud of this,” Bonin said. “We consider this an example of the work we do.”
The university is now breaking ground on a future “nucleus” of satellite research, called the Microsatellite Science and Tech Research. Slated to open in 2011, it will provide additional support services as the university expands its partnerships to the Nordic states and to more advanced satellites.
Storms and Sunspots
The university and other institutions will need to deal with a less predictable solar cycle as the decade waxes.
In past years, researchers in Canada were able to correlate the number of sunspots on the surface of the sun with the 10.7 centimetre solar flux, a measure of total radio emission that originates at the base of the corona.
But the last time the sun went through a solar cycle, something funny happened. Cycle 23 showed a weaker correlation between the sunspots and the solar flux, making it difficult to figure out what was going on.
When asked why keep track of the cycle, National Research Council researcher Ken Tapping showed delegates the economic damage one large coronal mass ejection can cause.
In 1989, a large solar flare wiped out power in most of Quebec for, in some cases, several days. Even when infrastructure was less advanced in 1859, a more massive storm hitting the Earth set some transatlantic cable terminals on fire, he said, and shocked cable operators doing their work.
Should such a storm hit today, the global damage would reach $2 trillion to $3 trillion, he added.
Even oceanic plane travel would be affected by a moderate storm.
“The only way (the pilot) can communicate is by high-frequency, and HF communication collapses when the sun becomes active. This issue is getting a lot of attention,” Tapping said.
Given that reliable data for the correlation only exists for 60 years, Tapping acknowledged there is uncertainty about how “abnormal” Cycle 23 was. But for what it’s worth, he said, the current solar cycle – 24 – is already showing abnormalities, pointing to an ongoing trend.
Gases, Reflections and Plankton
A number of other universities stepped to the podium to talk about their research. York University’s Yunlong Lin spoke about a small satellite constellation mission to measure greenhouse gases.
The group of three satellites would keep the sun always at the same position relative to themselves as they circle the planet, 15 kilometres of day, imaging a swath of land 250 kilometres square.
“We designed it so that almost all the major cities in the northern hemisphere can get the 250 by 250 measurements,” Mr. Lin said.
At Concordia University, researchers are learning how to adapt GPS signals to do “reflection” sensing of the earth.
The microwave L-band communications that these satellites use can be adapted for certain applications, including ocean waves, changes in water conditions around rivers, and surface moisture on land.
“Our instrument philosophy includes a minimal impact on satellite design, with minimal electronics, low power and using existing satellite resources,” said Scott Gleason, an assistant professor at Concordia.
As part of the Canadian government’s push to monitor natural resources, the Bedford Institute of Oceanography in Nova Scotia is tracking the fisheries through false-colour images of the ocean.
The research, funded in two missions tracking fisheries and chlorophyll, is working with the intergovermental Group on Earth Observations to provide a better picture of how well the world’s fish stocks are doing. The Canadian Space Agency provided startup funds from 2007 to 2010.
Pointing to a 2008 North Sea image showing plankton activity, the institute’s Marie-Helene Forget said it was easy to see the information, but not as easy to draw conclusions from it.
“You can’t quantify how much activity there is. That’s why you create algorithms for false-colour images,” she said.
“This type of information is what we are interested in for applications such as fisheries.”