Just weeks after Canada celebrated the 50th anniversary of its emergence as a space-age nation with the September 1962 launch of the Alouette satellite, a team of Canadian researchers has solved a longstanding mystery about one of the most disastrous episodes in that half-century of history: the same-day failure of Telesat?s Anik-E1 and Anik-E2 satellites after an intense ?space storm? in January 1994.
After probing archived images of the sun from just before the incident and re-examining the events surrounding the high-profile shutdown of the two satellites ? which garnered headlines around the world at the time, and may have cost Telesat as much as $70 million by some estimates ? Natural Resources Canada researcher Hing-Lin Lam and three colleagues have identified a huge ?coronal hole? that developed in the sun?s energy field, allowing high-speed ?solar winds? to stream relentlessly for several days from our fiery star towards Earth and its orbiting Canadian spacecraft.
The sleuthing scientists, whose findings in the cosmic cold case have been published in the latest issue of the journal Space Weather, have even provided smoking-sun proof of what caused the costly satellite outage ? a caught-in-the-act photograph in which the sun?s corona is shown with a huge swath of blackness representing the moment when the disastrous chain of events was set in motion.
As Lam and his co-authors explain in their study, the sudden failure of Anik-E1 on Jan. 20, 1994, knocked some Canadian television broadcasters off the air, disrupted telephone service in many northern communities and even left the Canadian Press wire service unable to deliver news to media clients across the country.
Although Anik-E1?s uncontrolled spin was stopped after several hours and put back into operation, the satellite crisis deepened when Telesat?s other key communications spacecraft ? Anik E2 ? also lost ?Earth lock? and went into an uncontrolled spin. Its failure meant ?virtually all of Canada?s television broadcast traffic? was knocked out, with programming on CBC, TSN, MuchMusic and other channels suddenly halted.
After about three days, service was fully restored when Telesat arranged to transfer its clients? blacked-out signals to U.S. satellites ? just one of several costs absorbed by the company, then a recently-privatized Crown corporation, as it scrambled to recover from the incident.
To correct Anik-E2?s erratic motion, Telesat engineers spent months constructing a Canada-wide system of ground stations that were able to send attitude-control signals to the satellite and ? by August 1994 ? get the craft fully operational.
However, the cost of the original service disruption, subsequent repair solutions and lost business was pegged at between $50 million and $70 million according to a 2009 study.
When the crisis flared in early 1994, Telesat officials explained that a magnetic storm of unprecedented strength, caused by sudden streams of energy from the sun, had been responsible for the disruption of the satellites.
Now, Lam and his team have traced the event back to the formation of the coronal hole in early January, a feature seen in images captured at the time by the Japanese Yohkoh Soft X-ray Telescope.
Distinguishing coronal holes from ?solar eruptions? or ?solar flares? that were initially identified as culprits in the Anik failures, Lam told Postmedia News that the hole phenomena are ?stable features that rotate with the sun. However, high-speed solar wind streams continuously emanate from the ?hole,? so if the hole is large and wide as the case here, the magnetosphere ? which is the magnetic shield protecting the Earth ? will be hit by the high-speed ?winds? for many days ? at least seven days in this case.?
Lam described how the relentless stream of solar winds created a large ?swarm of energetic electrons? that were ultimately ?more than the satellites? shielding could withstand, and a charge built up inside the satellite.?
He added: ?The discharge of this built up internal charge, triggered by natural electromagnetic transients, damaged a component of the satellites? momentum wheels, causing the satellites to spin out of control.?
Lam, who authored the paper with three current or former Telesat scientists, said reconstructing the precise cause of the 1994 incident is important because it may help satellite companies and space agencies better understand the threats posed by the sun?s energy emissions.
?It is important for satellite operators to monitor the real-time electron environment,? Lam said, adding that ?should situations warrant,? satellite operators ?should reschedule important maneuvers, or go into a heightened state of alert by putting a team ready to respond instantly to problems and prepare for recovery for an impending dire situation.?
He added that anticipating the threat caused by a coronal hole in the future could allow operators to ?delay dispatching commands to the satellite to avoid triggering a possible discharge.?
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