Michael Byers holds the Canada Research Chair in Global Politics and International Law at the University of British Columbia.

When Chris Hadfield noticed a small hole in a solar panel on the International Space Station in 2013, he tweeted: "Bullet hole … Glad it missed the hull." The damage was likely caused by a tiny piece of space junk, striking the station at a speed of up to 36,000 kilometres per hour.

Space junk is the legacy of 5,000 orbital-rocket launches since 1957. There are roughly 100 million pieces of space junk in orbit, with 500,000 of them being larger than one centimetre. Some pieces are dysfunctional satellites; others are discarded rocket stages; a few are tools lost by astronauts during space walks. Most are the result of collisions, which can turn two pieces of space junk into many small ones.

Story continues below advertisement

In 2007, China targeted a

derelict satellite with a missile, proving its ability to destroy working satellites but creating thousands of pieces of space junk. Two years later, an unintended collision between two other satellites created several thousand more. Just last week, a Japanese research satellite apparently broke up after a possible collision with space junk. One of the satellite's instruments had been provided by the Canadian Space Agency.

Space junk threatens Canada's interests in many ways. In 1972, this country built the first non-military geostationary communications satellite, Anik A1, enabling live TV broadcasts from coast to coast to coast. Today, our vast geography requires an increasing number of other space-based capabilities, from Arctic surveillance, to crop and forest monitoring, to Internet access in remote communities.

Canada's space industry generates $3.5-billion in annual revenue, with one quarter of that coming from 15 communications satellites owned by Telesat. Another large revenue generator is RADARSAT-2, owned by MacDonald Dettwiler, which produces high-resolution imagery for use in surveillance, search and rescue, disaster relief, police and military operations.

The threats posed by space junk extend beyond one-off collisions. In 1978, a NASA scientist warned that, once a certain amount of debris exists in orbit, the total amount will increase continuously – as collisions lead to more debris, followed by more collisions, and so on. This chain reaction has already begun, with debris levels in the lower, busiest band of orbit increasing 50 per cent in just five years.

Losing the ability to operate satellites in one or more orbital bands would compromise our communications-based economy. In the worst-case scenario, humanity could be trapped on Earth by clouds of orbiting debris, unable to explore the galaxies.

Governments are beginning to take the issue of space junk seriously; 23,000 pieces have already been detected, tracked and catalogued using Earth-based radar and telescopes. Most of the tracking is done by a "space surveillance network" operated by the U.S. military, which shares the information widely. Advance warning of collisions provides time for endangered satellites to be moved to safer orbits using on-board thrusters.

Story continues below advertisement

The European Space Agency is researching ways to remove derelict satellites from orbit, including through a new genre of "junk truck" spacecraft.

Canada participates in these efforts. Our first military satellite, Sapphire, launched in 2013, is dedicated to tracking space junk. The data are provided to the U.S. space surveillance network. Canada is also the only non-European country to be formally affiliated with the European Space Agency.

Canada has also participated in negotiations on guidelines that would require all new satellites to be able to de-orbit to Earth, or boost themselves into deep space at the end of their lifespan.

These negotiations recently stalled as a result of tensions between the United States and European Union on the one hand; and Russia and China on the other. Fortunately, Canada is well positioned to restart the talks. Closely allied with the United States on Earth, Canada is relatively independent in space. It never acquired ballistic missiles, which briefly enter space, nor has it joined the United States in missile defence, which involves interceptors that also enter space. Nor does Canada have its own launch capability, relying instead on U.S., European, Indian and Russian rockets. Sapphire, our lone military satellite, supports the interests of all space nations.

Space junk is a real and present danger. Canadian leadership is needed, now, to bring the great powers back together on this issue.