The Canadian military is looking for ways to prevent its satellites from being shot down or disabled, but is faced with an international legal vacuum that makes it tough to know how far the country can go to protect its property, government documents show.

The Liberal government's recent defence policy review committed the country to "the peaceful use of space," but also acknowledges government satellites, both defence and civilian, have become "potential targets."

A U.S. Senate committee was told by the country's Director of National Intelligence Dan Coats last May that China and Russia have stepped up their testing of anti-satellite weapons systems in the last year.

The concern has not gone unnoticed at the Department of National Defence where the increasing sophistication of systems, such as the Russian PL-19 Nudol, have presented a conundrum for military planners.

"We will be looking, for example, at including a requirement for 'defensive countermeasures' on future satellites," said air force spokesperson Capt. Trevor Reid in an email.

While that may sound an awful lot like the Reagan-era "Star Wars" concept, where it was envisioned that satellites would be shooting missiles at one another, the reality today appears much more benign.

There are not many so-called countermeasures to defend against a missile — or even the sea of hazardous space junk that floats around in orbit.

Many solutions are still on the drawing board but most, such as quantum dot technology which mimics the radiation signature of a satellite, are meant to confuse incoming missiles, acting as decoys from the intended target.

Warning signals, shutter control systems and defensive jamming capabilities are among the technologies under consideration by Canada, said Reid.

Untested international norms

China caused a sensation 10 years ago by blasting one of its weather satellites out of the sky.

Documents obtained by CBC News show Canadian defence planners are uneasy about how to proceed because legal concepts surrounding military action in space remain uncertain and untested.

"There is currently no policy consensus regarding whether, and what types of non-kinetic counter space measures, such as lasing or jamming, would be considered unacceptable," said the 2015 briefing book prepared for Defence Minister Harjit Sajjan, and recently released to CBC News under access to information legislation.

"The application of fundamental legal principles (e.g. self defence) can also be challenging from a practical perspective given the rapid development and unique characteristics of the technologies involved because the idea of the use of force in space remains underdeveloped."

The vacuum of international norms could be disastrous and lead to "potential misperceptions of actions, strategic instability" and the unintended escalation of a conflict, Reid said.

Cda Space Satellites 20130223

An artist's rendering of the Canadian NEOSSat satellite. The Canadian military is grappling with how best to prevent its satellites from being shot down. (Canadian Space Agency/Canadian Press)

Paul Meyer, a professor of international studies at B.C.'s Simon Fraser University, said there is not a total absence of international law on the issue.

There is the Outer Space Treaty of 1967, which stipulates the heavens are to be used for peaceful purposes; prohibits the stationing of weapons of mass destruction, such as nuclear warheads; and bars the militarization of celestial bodies.

"This is not a merely a belief but legally binding provisions of a treaty to which Canada is a party," Meyer said. "Ignoring these treaty restrictions on outer space activity is a gross omission in any discussion of security policy for outer space."

Hope for best, plan for worst

Canada's defence policy stipulates that the country is committed to the peaceful development of space.

Officials, however, seem to be hoping for the best and planning for the worst.

Three years ago, Canada and the majority of its so-called Five Eyes intelligence-sharing partners signed a memorandum of understanding to create the Combined Space Operations initiative.

The intention was to improve military co-operation and information sharing in space, and prevent interference with the satellites of member nations, among other things.

Reid said Canada is contributing to an international effort to develop a manual of international law applicable to military uses of outer space.

"This project aims to develop a widely accepted manual clarifying the fundamental rules and limitations of international law on military operations into, through, and from outer space," he said.