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Debris in low Earth orbit is like fast-moving shrapnel that endangers the systems we use for communication, navigation and research. Let’s not allow international militaries to make such a mess

A nuclear device explodes at a high altitude in U.S. government tests in the early 1960s designed to see whether atomic blasts in the ionosphere would disrupt missiles.Reuters

Michael Byers holds the Canada Research Chair in Global Politics and International Law. Aaron Boley holds the Canada Research Chair in Planetary Astronomy. They teach at the University of British Columbia and co-direct the Outer Space Institute.

The sky above the Pacific Ocean turned red on the night of July 9, 1962. In Hawaii, streetlamps went dark, telephones stopped working and burglar alarms began ringing – all because of a mysterious electromagnetic pulse. High above the ocean, at least six satellites were disabled. Only a few people would have understood what was happening. Fewer still would have realized that the course of humanity had just changed.

Science fiction explores core aspects of the human experience. The stories are used to confront difficult philosophical ideas and examine human behaviours in new or reimagined settings. They often offer a sombre reminder of our darker side and the many ways we can slide into armed conflict. Dogfights between Rebel Alliance and Galactic Empire starfighters are cultural echoes of the air battles of the First and Second World Wars.

The events and technologies imagined by sci-fi authors also have real-life influence, including on governments. U.S. president Ronald Reagan spent vast sums trying to develop space-based weapons, including lasers, as a means of missile defence. His critics responded by calling the program a Star Wars fantasy. Decades later, when Donald Trump asserted that space is a “war-fighting domain” and created a Space Force to dominate this “high ground,” he too was reaching for a future that sci-fi had already portrayed.

But among the lasers, missiles and battlestars, another vision is often present – one of peace, hope and co-operation. In Star Trek, we see the United Federation of Planets; in Babylon 5, there’s the Earth Alliance, extending over a dozen star systems. In real life – Earth, 2021 – we have the United Nations, the Outer Space Treaty and six decades of restraint concerning space weapons.

A wire-service story in The Globe and Mail on April 30, 1962, reports on the upcoming nuclear test in Hawaii. 'The experiment is not expected to endanger anyone,' the New York Times author writes.The Globe and Mail

The sky above the Pacific Ocean did not turn red in 1962 because of an alien invasion. This dramatic outcome was the result of the United States detonating a 1.4-megatonne hydrogen bomb at an altitude of 400 kilometres. The operation, named Starfish Prime, was designed to test nuclear devices as “counter-space” weapons that could be used to limit, and thus dominate, access to the region. But the effects of the bomb were far greater than expected. Four of the disabled satellites were American, one of which – Telstar 1 – had just introduced live TV broadcasts between the U.S. and Europe.

It was suddenly obvious that nuclear explosions in space threatened all satellites, with this lesson coming just as the considerable potential of these space-based machines for communications, navigation and reconnaissance was being realized. Cold War rivals, seeing their interests in a bright new light, immediately put aside their differences and negotiated the 1963 Partial Limited Test Ban Treaty. The world’s first nuclear arms control agreement, it prohibited nuclear tests in space. The Partial Limited Test Ban Treaty remains in force today, with a six-decade-long record of perfect compliance.

This exercise in mutual restraint was limited to nuclear testing, however. Satellites remained attractive as potential military targets because of their importance, their fragility, and the fact that they travel on predictable paths. The United States and the Soviet Union began testing non-nuclear anti-satellite weapons, including ground-based missiles and “killer” satellites able to manoeuvre onto collision courses with other spacecraft.

These tests revealed another serious problem – namely that high-velocity physical (“kinetic”) impacts in space can create thousands of pieces of space debris. Most are less than 10 centimetres across and too small to be tracked by ground-based radar or telescopes, but even a tiny piece can disable an operational satellite or pass right through an astronaut’s spacesuit. This is owing to the extremely high velocities of objects in orbit, with relative speeds of 36,000 kilometres an hour being typical in low Earth orbit – the busiest region, located just 100 km to 2000 km above the surface.

Any debris from an anti-satellite weapon (ASAT) test also creates a risk of subsequent collisions, putting all spacecraft at risk. Worse yet, in 1978, NASA scientist Donald Kessler identified that every collision increases the cross-sectional area of the material involved, greatly elevating the risk of further collisions, further fragmentations, and so on. This insight, based on lessons from the Asteroid Belt, is known today as the Kessler Syndrome. The phenomenon of runaway space debris that it describes could – if fed by human ignorance or arrogance – potentially render some orbital regions unsafe for centuries.

A satellite designed to remove space debris with a net is tested from outside the International Space Station's Japanese module in 2018. Anti-satellite weapons leave behind dangerous, fast-moving junk that endangers spacecraft and satellites.NASA/AFP/Getty Images

Sadly, there is no shortage of ignorance or arrogance in the militaries of powerful countries. In 1985, the U.S. Air Force decided to test an air-launched missile against a U.S. satellite, despite being warned by NASA about space debris and the Kessler Syndrome. The test created 285 trackable pieces and probably tens of thousands of smaller, but still dangerous, pieces. The Pentagon abruptly cancelled further tests and adopted debris mitigation guidelines just one year later.

Soon, the United States was promoting space debris mitigation internationally, creating a U.S.-Soviet Union working group in 1989. Four years later, an Inter-Agency Space Debris Coordination Committee (IADC) was formed that included the Russian and Chinese space agencies.

The IADC should probably have included militaries in addition to space agencies. In 2007, the People’s Liberation Army tested a missile against a Chinese satellite – reputedly without informing the Chinese leadership about the dangers of space debris. The strike took place at an altitude of around 850 km and created a huge amount of debris. In 2013, one of the pieces collided with and disabled a Russian satellite. Today, 14 years after the test, more than 2,800 trackable pieces remain in orbit.

The U.S. military, which relies on satellites far more than its competitors, has become even more resolute in its opposition to space debris. In 2015, General John Hyten, now the vice-chair of the Joint Chiefs of Staff, said kinetic anti-satellite weaponry “is horrible for the world … to me, the one limiting factor is no debris. Whatever you do, don’t create debris.”

China and Russia now appear to share this concern, while continuing to test ASAT weapons in ways that do not create space debris. Both have conducted “fly-by” tests where missiles are targeted at pre-selected co-ordinates in space rather than actual satellites. Both have tested highly manoeuvrable satellites that could be used to interfere with other satellites or, more benignly, to refuel or repair them. The United States condemns such tests whenever they occur, while operating its own highly-manoeuvrable robotic space plane that does secret things in orbit.

Condemnations aside, all these non-kinetic ASAT tests represent a marked change in behaviour, since none of the three established space powers has tested a missile against an actual satellite in more than a decade. One emergent space power has not shown the same restraint. In 2019, India tested a missile against a satellite it had launched for that purpose. Although the Indian military chose an impact altitude of just 283 km and assured everyone that no long-lasting debris would result, just over 100 long-lived and trackable pieces of debris were sent into elliptical orbits that crossed the orbit of the International Space Station. NASA administrator Jim Bridenstine called this a “terrible, terrible thing,” adding, “It is not acceptable for us to allow people to create debris fields that put [our people] at risk.”

Students cheer at their school in Ahmedabad, India, in March of 2019 after India shot down one of its satellites with a missile. 'India has done it,' one sign reads.Amit Dave/Reuters

The interceptor missile takes off from an island in India's eastern Odisha state on March 27, 2019.India's Press Information Bureau/Handout via REUTERS

Today, the risks posed by kinetic ASAT tests are escalating as companies build “mega-constellations” of internet satellites in low Earth orbit. In the past two years, the number of active and defunct satellites has increased by about 50 per cent, to more than 5000.

SpaceX is on track to add 11,000 more satellites as it builds its Starlink constellation and has already filed for permission for another 30,000 with the U.S. Federal Communications Commission. Others have similar plans, including Amazon, OneWeb and a Chinese state-owned company named Guo Wang. Within the next decade, we could see as many as 100,000 active satellites – and perhaps considerably more. Rwanda just filed “advanced publication information” with the International Telecommunications Union for two constellations, Cinnamon-217 and 937, that would have more than 300,000 satellites between them. Although Rwanda is currently unable to build and launch satellites, it could conceivably be claiming rights to radio spectrum in low Earth orbit in order to sell them to foreign companies.

In such a busy orbital environment, even low-altitude kinetic ASAT tests that seek to minimize long-lived debris would be problematic. As India unintentionally demonstrated, high-impact energies can place debris on eccentric orbits that extend much higher than the collision itself.

If a test like the 2019 Indian test was conducted in 2029, those eccentric orbits would not just cross the orbit of the International Space Station, but also the orbits of more than 50,000 new satellites, as well as China’s Tiangong space station. The risk of collisions would be substantially higher than in 2019, creating a very real risk of widespread satellite failures and even – after further knock-on collisions – the loss of safe access to certain orbits.

To borrow the language of environmental science, space debris is a “tragedy of the commons,” the Kessler Syndrome is a “feedback loop,” and just one more kinetic ASAT test could push the system over a “tipping point.”

Since the launch of Sputnik in 1957, the use of Earth orbit has entailed risks. Batteries explode, meteoroids strike, satellites run out of thruster fuel or simply wear out, and all the resulting debris creates operational hazards. However, the needless production of additional debris through kinetic ASAT weapon-testing is more than just rain in the bucket. It’s a flat-out denial of Kessler’s prescient and powerful insight: Every collision carries the potential to cause not just one, or a few, but many other collisions.

A projection of space debris generated by the Aerospace Corporation's Satellite Orbit Analysis Program (SOAP).JAMSTEC/Earth Simulator Center

New practices are needed, and quickly. One major step forward would be a kinetic ASAT test ban treaty. Such a treaty would prohibit the use of any high-velocity physical strikes while testing weapons in space.

Support for such a treaty is growing. In 2020, the United Nations General Assembly adopted Resolution 75/36 on “reducing space threats through norms, rules and principles of responsible behaviours.” Member states were encouraged to study potential threats to satellites, identify activities that could be considered irresponsible or threatening, and share their views on the development of new rules with the UN Secretary-General.

Those views, compiled in a recently released report, show strong support for restrictions on kinetic ASAT testing, including on the part of Russia, China and the United States. Just as importantly, not a single country expressed the view that kinetic ASAT testing is an appropriate or internationally legal action.

In September, hundreds of experts – including Nobel laureates, former prime ministers and retired astronauts (as well as the authors of this essay) – signed an open letter that urged the United Nations to take up consideration of a kinetic ASAT test ban treaty. Such a treaty would not solve all the challenges associated with human expansion into space, but it would help to protect the extraordinarily valuable orbits directly above our heads.

The momentum continues to build: Earlier this week, the First Committee of the UN General Assembly voted to create an open-ended working group to develop new rules for military activities in space. The result of a British initiative, this could be the first step toward a multilateral treaty, although as a nuclear-armed permanent member of the UN Security Council, Britain is not the ideal country to lead on this file. Canada, a non-nuclear “middle power” and one of the 37 co-sponsors of the resolution, is much better suited for this role – as demonstrated by former foreign minister Lloyd Axworthy’s successful championing of a 1997 treaty banning anti-personnel landmines. Our new foreign minister, Mélanie Joly, should make a kinetic ASAT test ban treaty one of her priorities.

In sci-fi, a white-knuckled escape through an asteroid belt is an almost standard trope. Astronomers laugh when they see this because asteroids are widely separated from each other. But the debris field that human beings are creating in low Earth orbit is much more dangerous. Sending spacecraft at high speeds through a debris field can indeed result in heavy losses. In that sense, the sci-fi authors got it right.


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