Federal officials got no warning that a Russian rocket would soar through Canadian airspace last December before splashing down, newly released documents show.

Instead, military and government officials were given three different re-entry points — all far removed from Canada — before learning the rocket had actually come down over Labrador.

The incident highlights a vulnerability of Canadian airspace even as the air force scrambles jets to counter threatened Russian bomber intrusions in the High Arctic.

The Russian Proton-K rocket, carrying three navigation satellites, was launched Dec. 25 from the Baikonur facility in Kazakhstan. Its bus-size fourth stage went into a low orbit for more than a day before crashing back to Earth.

Norad military experts tracking the object alerted Canadian officials and others on Christmas Day that the booster was expected to re-enter the atmosphere somewhere off Antarctica, south of Australia.

But by the next day, the radar-based prediction shifted to a spot over the Pacific Ocean, about 200 kilometres southwest of Nicaragua. Then Norad said the booster would come down about 370 kilometres east of Florida, in the Atlantic Ocean.

In the end, the booster tumbled back to Earth about 120 kilometres north of Blanc Sablon, Que., over a barren stretch of Labrador. The estimated re-entry point was just a few hundred kilometres southeast of the Goose Bay air force base.

The rocket then disappeared from radar. Any debris that did not burn up in the atmosphere is believed to have carried on into the Labrador Sea.

'Not sufficient time'

Norad's operation centre at Cheyenne Mountain, Colo., notified Canadian officials of the splashdown minutes after the event, leaving no time for warnings to fishing boats, cargo ships or populated places. The rocket's path had taken it across the Maritime provinces.

"At this time there was not sufficient time to ask the CCG (Canadian Coast Guard) to notify any vessels," says an internal email from a Public Safety official.

Documents detailing the incident, including Norad reports, were obtained by The Canadian Press under the Access to Information Act.

The Proton-K re-entry was reminiscent of a 2005 incident, when a U.S. military rocket splashed down in the vicinity of the Hibernia oil platform, on Newfoundland's Grand Banks, shortly after its launch from Florida.

The planned launch of the Titan IV B-30 rocket prompted Premier Danny Williams to order an evacuation of several offshore-oil platforms.

But the order was soon rescinded when American air force officials assured Ottawa the risks were small and the rocket would be destroyed if it veered off course.

A space debris expert, however, says the uncertainties about splashdown rise significantly if an object has achieved orbit, as did the Russian rocket.

Unpredictable aerodynamics

"Once something gets into orbit, where it's going to come down is really unknown," said William Ailor, director of the Center for Orbital and Reentry Debris Studies in El Segundo, Calif.

Objects like boosters can tumble, making their aerodynamics unpredictable, and the upper atmosphere itself can be uneven because of solar storms and other factors, he said in an interview.

"You know the path but you don't know where along the path it's going to come down," Ailor said. "If you're thinking about trying to warn somebody, it makes it very difficult to do that."

Modern orbital hardware is more frequently being equipped with control mechanisms, such as re-entry thrusters, to better control where the debris comes down, he added.

Canada's nastiest encounter with space debris occurred in 1978, when a nuclear-powered Russian satellite broke up across the Northwest Territories, triggering an expensive cleanup of radioactive material. The Soviet Union eventually paid $3 million in compensation for the crash of Cosmos 954.

A spokeswoman for the Public Safety Department said no protest over the Dec. 26 rocket re-entry was made to the Russian government.

"No followup with Russia was deemed necessary because the use of Canadian territory for the re-entry was not planned and there was no evidence that anything physically survived re-entry," said Jacinthe Perras.