Many have tried to define a space weapon, myself included. None of us have come up with a satisfactory definition, which is one on many reasons why a treaty banning space weapons is not in the cards.
After the Bush administration disposed of the ABM Treaty, the Chinese and Russian governments dipped into the old Soviet playbook and tabled a draft “Treaty on the Prevention of the Deployment of Weapons in Outer Space.” Here’s their language defining space weapons:
The term ‘weapon in outer space’ means any device placed in outer space, based on any physical principle, which has been specially produced or converted to destroy, damage or disrupt the normal functioning of objects in outer space, on the Earth or in the Earth’s atmosphere, or to eliminate a population or components of the biosphere which are important to human existence or inflict damage on them;
A weapon shall be considered to have been ‘placed’ in outer space if it orbits the Earth at least once, or follows a section of such an orbit before leaving this orbit, or is permanently located somewhere in outer space.
Please note that this definition does not capture ground-based ASATs. The Russian and Chinese draft treaty is problematic in many other respects, as well. For example, unless there are common understandings on whether a multi-purpose device has been “specially produced or converted” so as to qualify as a space weapon, the proposed ban has no practical effect.
Philip Baines, a Canadian diplomat with uncommon technical expertise has proposed another definition of a space weapon:
a device based on any physical principle, specially designed or modified, to injure or to kill a person, irreparably damage or destroy an object, or render any place unusable.
In Phil’s view, form follows function. For example, “a satellite that is designed to be a weapon will also look like a weapon, and a satellite that is designed to be benign will look benign.” But satellite payload inspections, first proposed back in the Eisenhower administration, remain beyond the pale. And it may be far-fetched to assume common understandings on the form and function of non-inspected space-spaced objects. Nor can states rely on externally observable differences to distinguish satisfactorily between, say, a missile defense interceptor and a ground-based ASAT. As with the draft Russian and Chinese treaty text, Phil’s definition lends itself to disagreements over what “specially designed or modified” really means.
Theresa Hitchens, long a stalwart promoter of space security, now at UNIDIR, has defined space weapons this way:
destructive systems that operate in outer space after having been launched directly from Earth or parked in orbit.
Theresa’s definition has the benefit of concreteness, but it may still be too limiting: Is a “system” that doesn’t destroy a satellite but renders it nonfunctional a space weapon or not? And how do we deal with a device or weapon system with multiple potential purposes, such as an interceptor missile that can be used for ballistic missile defense as well as for ASAT purposes? An inclusive definition of a space weapon would foreclose essential military capabilities, while a limiting definition would allow many kinds of latent ASAT systems to run free.
In my view, we’re barking up the wrong tree in trying to define space weapons. How nations act in space matters far more than how they define space weapons. A treaty banning space weapons remains a distant goal. There are other ways, far more realizable, to strengthen norms for responsible space-faring nations – including the norm of not using satellites for target practice.
Over the past two decades, Iraq, Iran and Libya have tried to interfere with satellites. Is this a practice that responsible space-faring nations wish to emulate? The European Union has endorsed the Stimson Center’s proposed norm of “no harmful interference” against space objects. Yes, this invites a debate over the definition of “no harmful interference.” But reaching a reasonable conclusion on this subject is far easier than trying to define a space weapon.
The Obama administration has still not cleared its throat on this or related subjects. It took almost sixteen months for the Reagan administration to come up with a negotiating proposal for strategic arms reductions. It is taking even longer for Team Obama to propose a space diplomacy initiative.
Update | 11:27 am Jeffrey adds: Such definitional difficulties are precisely why I have argued for a “ban [on] the testing deployment and use of kinetic energy ASATs (KE ASAT ban), which destroy their target satellite by slamming into it, creating significant amounts of space debris.” I will be making the same pitch again in Geneva this month.