Sam BlackPurposeful Interference

The Keeper of the Shoeboxes touched on the new National Space Policy (.pdf) a few weeks back, focusing on the diplomatic side of it. As he noted, the language on diplomacy and arms control is substantially different from that in the 2006 policy. But I wanted to focus on a different aspect, the concept of “purposeful interference.” Specifically, the new policy states that “Purposeful interference with space systems, including supporting infrastructure, will be considered an infringement of a nation’s rights.”

Interference with space objects has been an interest of mine for a few years now, so I was intrigued when in popped up in the new NSP. A few things jump out. First, the term isn’t defined. There are a bunch of different ways that one might purposefully interfere with a satellite, but some are more pernicious than others. China’s ASAT test in 2007 increased the amount of trackable debris in LEO by something like 25%. This is something we in the space community refer to as “bad.” But what about jamming? Jeffrey noted way back in 2004 that the US had deployed a jamming system. So if we have to press that bad boy into action, are we infringing on the target’s rights? And more fundamentally, is all purposeful interference created equal? Of course, even if the answer to that question is “no,” leaving the term undefined increases flexibility for responding to incidents in the future – the context or extent of an incident may elevate the significance of a non-destructive interference event to the point where it poses very serious concerns. In such a case, having a definition which assigns less importance to temporary and reversible interference could be a hindrance.

To its credit, the new policy seems to recognize the trouble with a Manichean view of purposeful interference and sovereign rights. The document’s attempt to manage this appears to come in the section detailing the responsibilities of the Secretary of Defense, which include “Develop[ing] capabilities, plans, and options to deter, defend against, and, if necessary, defeat efforts to interfere with or attack U.S. or allied space systems.” Notice the either/or within the “interfere with or attack” clause. My reading is that, within the bounds of the concept of purposeful interference, however defined (or not), there exists a more restrictive concept of attacks on satellites.

I suspect that this and other distinctions are borne of technical as well as strategic considerations. The general impression given by those in the know is that it’s much more difficult to attribute actions on the less destructive end of the purposeful interference spectrum – like jamming or lasing – to a specific actor. If you test or use a KE ASAT mounted on a modified ballistic missile, it’s a little trickier to deny that you were involved. Strategically, I don’t know if you want to invoke the threat of military action every time, say, Iran decides that its citizens really don’t need to be able to watch BBC Farsi.

This gets us into a second interesting aspect of the “purposeful interference” concept, the selection of “purposeful” as opposed to, for example, “harmful,” as in the paper I linked to above. While the “purposeful interference” concept puts us on stronger ground in terms of legitimizing any possible response (be it a demarche, sanctions, or something more severe), it also raises the evidentiary bar in terms of the level of space situational awareness (SSA) required to demonstrate that the interference was in fact “purposeful.”

Victoria Samson and I have noticed (.pdf) a pretty big bump in unclassified U.S. Air Force SSA spending over the past couple years. And by “big bump,” I mean that the Air Force requested $275 million for a set of SSA programs for Fiscal Year 2009. For FY 2010 it requested $375 million for these programs and got $530 million. And for FY 2011, the request is up to $900 million! So the request handed to Congress this February for SSA was more than triple the request Congress got in February 2008. That’s a lot of cheese!

Though the increased investment in SSA is encouraging, it’s an open (or classified?) question whether it can definitively answer three key questions raised by the new NSP: 1) when interference occurs, will we be able to attribute it to a source with high confidence; 2) when interference can be attributed to a source, will we be able to determine that it is intentional; 3) when intentional interference is judged to have occurred, does it cross the threshold into the realm of an “attack”?

The first of these, as mentioned above, is a difficult question to answer. The second is even tougher. If a communications satellite in geosynchronous orbit starts drifting to the point where it begins interfering with a U.S. satellite in a neighboring orbital slot, is it intentional? Can the drift be proven to be intentional as opposed to a correctable (or not) malfunction? After all, when a satellite becomes unresponsive, even the operator may not know whether a recovery is possible for days or longer.

My intuition is that our capacity to answer the first question will improve in tandem with upgrades to our SSA capabilities. And answering the third question is analogous to assessing other incidents. For example, if there is a terrorist attack that may or may not be state-sponsored, does this qualify as an attack by that state? Answers to this question must account for a mix of political considerations, the strategic context, and hard evidence. But that second question is going to be tough, especially when it involves countries using dual-use technologies, countries with a mostly opaque picture of the operational environment that exists in space (but I didn’t know one of your satellites was in the area!), or cases when the answer boils down to making a guesstimate about another actor’s intentions.

Because making a determination that interference is in fact purposeful is so difficult, the new policy also offers another category when it talks about “responsibility” and discouraging irresponsible behavior. My impression is that this term may end up serving as some sort of backstop for behavior we can’t or don’t want to publicly attribute or describe as being purposeful, but want to condemn nonetheless. So an “irresponsible” act may be one step below one that qualifies as “purposeful interference.”

The graph below demonstrates my pathetic lack of artistic ability and summarizes my thoughts on how the U.S. might view interference with its satellites. Do any readers have a different view?

Seriously, even MS Paint is hard for me...


  1. Mark Gubrud (History)

    You are right that, in most cases, we probably wouldn’t respond with violence to nondestructive, temporary and reversible interference with one of our less-essential satellites. So, if we don’t want the Iranians to jam a BBC uplink or laser-dazzle one of our photorecce birds, wouldn’t it be good to have a binding commitment from them not to do so? And isn’t it likely that if 180 or so nations, including the US, signed onto a treaty explicitly banning such forms (and all forms) of purposeful “harmful interference” with space objects, the aspiring spacefarers of Iran would too? Maybe even North Korea. We could then have a formal process for bringing the weight of the world community to bear on any violators.

    It is important, though, to distinguish between uplink jamming and downlink jamming, or more generally between interference with a space object and interference with the use of a space object. For one thing, space arms control should not be asked to carry the burden of protecting anyone with a GPS receiver in hand from being shot at.

    Trying to ban downlink jamming is pointless when it is so easy to overpower the relatively faint signal from a satellite, at least within a limited area, and when JDAMS and other uses of satellite signals provide such compelling reasons for someone under attack by the US military to do so.

    Uplink jamming and dazzling are relatively harder to do, but easy enough that it would be foolish to expect that states would not retain the capabilities. A ban on weapons for such interference is still useful, however, both to reinforce a ban on their use, and to suppress a global open market for the needed equipment.

    For internal policy purposes, a distinction between “attacks” and the broader category of “purposeful interference” may be useful, but for the purpose of framing a global convention, it is probably better to lump together all forms of “purposeful” or “intentional” harmful interference and ban them equally. (I don’t know why the NSP uses “purposeful” rather than “intentional”; seems to me it is easier to make the case that some interference was intended than it is to prove what its purpose was.)

    Of course, such a ban will do little to address the urgent questions of arms race and crisis stability if it is silent about the development, testing, production, deployment, stockpiling and transfer of weapons for harmful interference. And of course, it will be impossible to restrict antisatellite weapons if satellites are allowed to carry weapons themselves. That is why we need a comprehensive space security convention, one that begins with two basic declaratory priciples:

    1. Space objects stationed in outer space shall not carry weapons, and weapons shall not be stationed in outer space nor prepared for stationing in outer space.

    2. Space objects stationed in outer space shall enjoy sanctuary from intentional harmful interference or threats of harmful interference, and weapons for harmful interference with space objects stationed in outer space shall not be prepared.

  2. Paul Meyer (History)

    The inclusion in the NSP of the new terminology of “purposeful interference with space systems” simply adds ambiguity where clarity would have been welcomed. Why abandon the “harmful interference” term which is enshrined in the Outer Space Treaty and which could provide a generally acceptable basis for further internationally agreed constraints?

    As Sam notes, the evidentiary bar regarding “purposeful” is difficult to reach, as is the case for “responsible action”. There should be no inference that non-destructive interference is to be permitted. The draft Russia/China PPWT (CD/1839, 12 Feb 2008)includes in its prohibition on the “use or threat of use of force” against space objects, actions “temporarily or permanently disrupting their normal functioning”. The benefits of an expansive prohibition for international cooperation in space security should be considered before carving out exceptions or inviting harmful acts.

    Another ambiguous phrase in the same NSP sentence is that the purposeful interference “will be considered an infringement of a nation’s rights”. What recourse would be legitimate for a state whose rights have been so infringed? Would it qualify as a “hostile act” for which a act of self-defense in response would be justified?
    One hopes that there will be some diplomatic follow-up to the NSP to clarify its intent in so far as ‘responsible’ space action is concerned.


  3. Mark Gubrud (History)

    The context of the use of the term “harmful interference” in the OST implies that such “harmful interference” is expected to be an unintended result of some other space activity – unintended, but whose possibility is foreseeable, hence the demand that a Party which foresees the possibility of interference with one of its own space objects due to the activities of another ask for consultation, or that a Party which foresees the possibility of interference with another’s space object due to its own activity provide such consultation.

    These provisions, and other terms of the Treaty, can be seen as implying an expectation of noninterference, but it is rather weak and the context is not one of possible intentional conflict and warfighting in space. Thus it is prone to being easily overridden by Article 51, etc.

    It certainly would be cognitively dissonant to expect that a nation intending to interfere with another nation’s satellite as an act of war should first consult with that nation as to its intentions.

    That is, I think, why the drafters of the NSP saw a need to introduce the concept of “purposeful interference” although, as I wrote above, I think the word “intentional” would be better, rather than raising any question of what the “purpose” of intentional interference might be (other than the obvious purpose of, well, interfering).

    You are right that we certainly do not – or should not – want to imply that “temporary and reversible” or otherwise “soft” interference is okay, but unfortunately the US has in recent years taken the position that we might do just this. I don’t think that is quite the intent of “purposeful interference” however, since even “temporary and reversible” interference could obviously be “purposeful,” and the NSP puts the US on record as opposed to any “purposeful interference” – at least with US and “allied” space objects.

  4. Theresa Hitchens (History)

    The ITU Constitution also uses the term “harmful interference” which is defined as follows: “Interference which endangers the functioning of a radionavigation service or of other safety services or seriously degrades, obstructs or repeatedly interrupts a radiocommunication service operating in accordance with the Radio Regulations.”

    Certainly, the clause on purposeful interference seems to be contradicted by page 14’s reference to DOD capabilities for “space control and force application missions.” I would assume that the idea is to lay a “deterrence” marker on interference, but that is really rather hard to do if you are yourself maintaining plans and systems for undertaking interference (at least during conflict.) I don’t see the new NSP as overturning USAF and DOD doctrine to consider “temporarily and reversible” means of attack as a possible offensive option.

  5. John Schilling (History)

    If one is going to propose a treaty or other legal regime covering hostile action by or against space vehicles, I think one needs to start by acknowledging that there are two very different states of affairs called “peace” and “war”, and the rules are going to be very different. If, for example, the United States were to go to war with China, the Chinese will almost certainly attack or otherwise purposefully interfere with USAF satellites which are actively supporting the war effort. To the extent that it is legally and morally acceptable for them to wage war in the first place, it is acceptable for them to shoot at our satellites. And vice versa. And whether it is legally or morally acceptable or not, it will almost certainly happen – to the detriment of any legal regime which promised to make it not happen.

    We can still reasonably hope to make these things not happen in peacetime. There’s a lot of harmful activity (e.g. hardkill ASAT test shots) that we can reasonably hope to negotiate out of existence during peacetime. And a few things (e.g. nuclear ASATs) that we can maybe hope to keep off the menu even during wartime. But we have to know the difference. And any meaningful treaty or law will have to recognize three categories of action – generally permissible, act of war, and war crime – rather than just “permitted” or “forbidden”.

    This doesn’t seem to be a problem on land, sea, or air. For example, sailing warships on the high seas is generally permissible, sinking someone else’s warship is generally an act of war, and sinking someone else’s passenger liner is generally a war crime.

    A similar understanding is, I think, generally lacking w/re orbital rules of engagement. And sadly so. It will be much easier to convince honest nations to agree to, and dishonest ones to abide by, rules of engagement that make Earth orbit a generally safer place, if it is clear that these rules do not prevent them from taking reasonable defensive measures in time of war. And yes, firing the first ASAT of the war is a defensive measure if it is fired at e.g. a GPS satellite being used to guided JDAMs.

  6. Mark Gubrud (History)

    Re Theresa’s comment: I don’t see a contradiction between declaring that interference with one of our or our friends’ space systems would be an infringement on our rights, and an implied threat that we might interfere with somebody else’s satellite. That’s deterrence precisely. Not that I approve of such a stance, but it’s not the worst you could do if you still aren’t ready to talk real arms control.

    Re John’s comment: To propose a treaty which explicitly allows “hostile action” in the event of “war” while banning it in times of “peace” is to propose something weaker than the weakest arms control, something so weak it’s hard to see that it would mean anything at all.

    Now, if you want to propose really, really weak arms control, a ban on “hardkill ASAT test shots” is an excellent candidate. Assuming it allowed “hardkill” exoatmospheric BMD test shots, as well as non-impacting ASAT flybys, it would have exactly zero effect on any (fully compliant in letter) Party’s ability to develop, test, perfect, and deploy en masse even the kinetic energy ASATs it would ostensibly address, to say nothing of the non-debris creating ASAT technologies that are far more likely to be tested, deployed, and potentially used in the future.

    Bearing in mind that real combat in space is likely the province of major powers which possess nuclear weapons, the purpose of space arms control is less to restrict what might happen in the event of war than it is to make war less probable by blocking the path of a destabilizing space arms race.

    Given this context, the point that using an ASAT might be considered a “defensive measure” does not override the fact that agreeing to, and adhering to, a global ban on all space weapons, can be equally well (or I would say, far more plausibly) a defensive measure.

  7. Terry M. (History)

    States are still responsible for the object that they put into earth orbit. If a State refuses to remove a “non/mal-functioning” satellite from a valuable orbital position (efficiency argument), or to prevent it from becoming a danger to other objects (liability agrument), is a second-party State guilty of “purposeful interference” if it removes the “non/mal-functioning” satellite to another orbital location (or simply sending the object into deep space)?

  8. Mark Gubrud (History)


    Very good question. There is not currently any basis in space law for any nation or other entity to undertake or authorize the forcible disposition of a space object placed in orbit by another nation. This is especially problematic in that there is so much junk out there whose origin is unknown and probably can’t be determined. No one has any authority to go and clean it up!

    Orbital slots in GEO are assigned by the International Telecommunications Union to states, which license commercial or other entities to use them. Many slots have been assigned which are not currently in use, so there is no “efficiency” argument to be invoked outside of the ITU’s proceedings. It’s not clear that even the ITU’s reassignment to another state (should that ever occur) of an orbital slot containing a dead satellite would constitute authorization of the new assignee to remove or interfere with it. The question is academic, however, and the issue is actually more serious than that, since a nonfunctional satellite in GEO won’t stay put, but rather will drift out of its slot and potentially collide or otherwise interfere with satellites in other slots. Brian Weeden has a good article on this in Space Review.

    Under the Outer Space Treaty, “If a State Party to the Treaty has reason to believe that an activity or experiment planned by it or its nationals in outer space… would cause potentially harmful interference… it shall undertake appropriate international consultations before proceeding….” (emphasis added). This would seem to rather pointedly not apply to the case of a malfunctioning satellite, since it’s hard to ask for retroactive consultation about an action (launching the satellite) that has already been taken. But at least, this language seems to imply (with other language in this and other treaties) a general responsibility to avoid wanton, if unintentional, interference, which could perhaps be extended to a responsibility to take corrective action when possible.

    The existing structure of international space law is clearly inadequate, and although the OST provides a solid foundation, it remains a foundation to be built upon. Under a Comprehensive Space Security Convention, it should be possible to both ban the creation of space weapons arsenals, and, under a regime of monitoring and limits, authorize the possession and use of what might otherwise look like potential weapons to “interfere” with space junk that nobody wants left in orbit, perhaps under strict (e.g. consensus) rules for authorizing such actions.