Was it legal for India to conduct an ASAT test which created hundreds of detectable fragments of debris at a 250 km orbit, some of which may remain in orbit for up to a year? Of course it was. Just like the US test in 2008 was legal (which was also at around 250 km). UN Debris Guideline #4 provides cover for low-altitude ASAT tests by only asking countries to avoid against “harmful activities that generate long-lived debris.”
What is today accepted as “short-lived debris” may nevertheless pose a risk to satellites. Explosions at 250 km will inevitably shoot some debris into higher orbits and this may be too close for comfort. Remote sensing satellites (which have flown in orbits as low as 150 km in order to get closer to their subjects) face even greater risks from low-altitude ASAT debris. In light of this, the international community must continue to strengthen the rules around even these low-altitude ASAT tests.
But now let’s move on to a far more important question: Was the 2007 Chinese ASAT (at 865 km) test legal? A spokesman for Prime Minister Tony Blair made the clearest statement on the legality of the Chinese test just days after the test: “We believe this [test] does not contravene international law.”
Despite the consensus that the test was legal, I disagree. Article IX of the OST requires that parties to the treaty conduct all of their space activities “with due regard for the corresponding interests of all other States Parties to the Treaty.” How could polluting LEO with thousands of destructive pieces of debris for hundreds of years possibly qualify as operating “with due regard”?
There are other arguments that such ASAT tests violate existing international law. Here is a quote from Prof. Aoki Setsuko:
“ASAT attacks producing significant amounts of space debris that may affect the orbital environment for decades could be classified as a prohibited method or means of armed conflict under Art. 35(3) of [the Additional Protocol I to the Geneva Conventions of 1949] depending on the definition of the “natural environment.” (Routledge Handbook of Space Law p. 223)
Here is the law referred to by Prof. Aoki:
“It is prohibited to employ methods or means of warfare which are intended, or may be expected, to cause widespread, long-term and severe damage to the natural environment.”
There are certainly other arguments, such as those based purely on international environmental law. Please share those arguments in the comments below. I am very interested in your thoughts. It’s time to move this conversation forward.
Mark J. Sundahl