When can "civilian, including commercial, infrastructure elements in outer space" be legitimate military targets?

Question

The following quote of the Russian Foreign Ministry spokesman Konstantin Vorontsov found in Fox News' October 27, 2022 Russia threatens to target Western commercial satellites like Elon Musk's Starlink

Vorontsov did not directly mention Starlink but in a Wednesday statement said, "We would like to specifically stress an extremely dangerous trend that goes beyond the harmless use of outer space technologies and has become apparent during the latest developments in Ukraine."

"Namely, the use by the United States and its allies of civilian, including commercial, infrastructure elements in outer space for military purposes," he added, noting that satellite use "constitute[s] indirect participation" in the war. "Quasi-civilian infrastructure may become a legitimate target for retaliation."

and

Vorontsov argued that the use of commercial satellites to benefit Ukraine in the war violates the Outer Space Treaty and warned that it could start a "full-fledged arms race in outer space."

together with the recent questions and their numerous answers:

• Are power plants legitimate military targets under international law?
• How could SpaceX prevent military use of their satellites while preserving free speech absolutism?

suggest that the following has a good chance of being answerable based on facts and international laws and agreements, including the Outer Space Treaty Vorontsov mentions and more recent agreements:

Question: When can "civilian, including commercial, infrastructure elements in outer space" be legitimate military targets?

Answer 1

Civilian infrastructure can be a legitimate military target if two clauses are simultaneously fulfilled:

1. it is used for military purposes and its destruction will offer a definite military advantage;
2. it is not indispensable for survival of civilian population relying on its functionality.

The above criteria seem quite simple, but the problem here is that historically the attacked infrastructure belonged to one of the combatant states and was situated in its territory... which is not the case in the situation the linked article refers to.

Outer Space Treaty is kind of a red herring in this context. Article VI might be interpreted as USA being responsible for usage of private civilian orbital assets belonging to its sitizens (i.e. Article VI states that states are responsible for any harm caused by their orbital assets, whether government-owned or private), but in context of military usage the treaty only prohibits the usage of space assets for activities related to weapons of mass destruction. Usage of orbital (but not celestial-body based) civilian infrastructure for military communications, recon or even to house conventional weaponry is not regulated by it (so you could put a cannon on a space station, but not on a Moon base; I guess the designers of the treaty just intentionally left holes in it to possibly gain advantage in preparation for future space wars?). The legality of attacks on civilian infrastructure is regulated by the Geneva Conventions.

The consensus in common military practice is that any communication equipment used to facilitate military communications is fair game, period. Human rights organisations tend to have a different view on situation, but are rather powerless to prevent such actions and can only file protests after the fact. To provide some relatively recent (but not too recent) examples - during the Gulf War (1990-1991) the coalition forces extensively attacked Iraqi communications hubs; during the war in Chechnya Russian forces carried out multiple attacks on radio and television hubs controlled by the insurgents. As such, one might conclude that attacking civilian communication hubs used by the opposing military is legal; but in this particular case the hubs in question are not in the territory of one of the belligerent states, and not even owned by one, which makes this situation rather unprecendented.

Note that space powers tend to keep their toys to themselves, tend not to confront each other directly, and rarely lend them out; so prior to this moment, in no conflict there was a situation where one combatant used satellites for military communications, and the other side possessed capability to destroy an object in orbit.

Answer 2

When sides are at war. Russia and USA are not.

Under the laws of armed conflict, a Russian strike on a private US company’s satellite could be seen as an act of war to which the US could respond. White House spokesman John Kirby said any attack on US infrastructure would be met with a response (source).

It is likely not possible to attack the civil infrastructure of some country and expect no retaliation just because some other military uses the infrastructure in its intended way (providing basic internet access in this case). Not to say "illegal" or "war crime" but not legally possible without starting the war.

Russia can do this but they would be seen as a country that started the war. And while Russian PR will go long ways to prove the opposite, this still likely to have unfavorable consequences worldwide.

Likely infrastructure in space is comparable by status to the infrastructure that is not in the owning country, but also not inside the two other countries at war. Same as if USA would strike the Baikonur now - it is the infrastructure owned by Russia, not in Russia (in Kazakhstan), not in Ukraine, and Russia is very unlikely to see such a strike as appropriate and would probably say, the war begins.

Answer 3

I disagree with the answer by Danila Smirnov.

What Russia is doing now is saber rattling. This is not an attack. It's just saber rattling. Russia has performed far strong saber rattling, including threatening to nuke Britain and Germany. Saber rattling versus following through on the saber rattling are very different things.

The Outer Space Treaty has multiple relevant parts. Other than banning putting weapons of mass destruction in orbit, on the Moon, or on other celestial bodies, the Outer Space Treaty is moot on military uses of space. It does not distinguish between military and non-military assets in space. Section VII says that nation states are liable for damage to the space assets of other nation states. Section VII does not ban anti-satellite weapons. It merely says that a nation state is liable for damages to the space assets of other nation states.

Section VI spells out what comprises the space assets of a nation state. This section states that nation states are responsible for any assets they have in space. This includes space assets launched by / owned by non-governmental organized in that nation state. One consequence of this that if, for example, a privately-owned satellite goes out of control and collides with another country's space asset, it is the nations state that is responsible. (Whether the responsible nation state in turn goes after the private organization is an internal matter.)

Another consequence of Section VI is that the nation state responsible for a space asset is that the asset is under the protection of that nation state, regardless of whether or not the asset is government owned. An anti-satellite attack by Russia on a Starlink satellite would be a direct attack on the US, and by extension, would be an attack on NATO.

While the US has provided lots of defensive military equipment and training to Ukraine, it has not provided offensive military equipment, US boots on the ground, or US Air Force planes overhead. This has been a proxy war to date. A direct attack on the US such as a Russian ASAT attack on a Starlink satellite most likely would change that metric.

That said, there is a way for Russia to attack Starlink communications without using an ASAT attack, which is to jam or spoof the signals. A good number of countries jam or spoof GPS satellite broadcasts, and these are not taken as direct attacks on the US. Jamming or spoofing Starlink communications could disrupt those communications for ten or twenty kilometers from a combat zone, and that might well be good enough.

To answer the specific question,

When can "civilian, including commercial, infrastructure elements in outer space" be legitimate military targets?

The answer is almost always. Most civilian space assets are dual use technologies (technology that can be used for both military and non-military purposes). Reconnaissance, communication, and weather satellites are dual use. I'm having a hard time thinking of a space asset that is not at least potentially dual use.