It is (almost) official now – the RS-24 missile that Russia tested on May 29, 2007 is a multiple-warhead version of Topol-M. That was my guess at the time of the test, but now I have had it confirmed. The missile, of course, have a new warhead section, but it is a Topol-M. It was said to use a guidance system that shares technology with that of the Bulava SLBM and, just as I suspected, it will be using the same warheads. It appears, though, that MIRVed Topol-M will carry no more than six warheads (the range was reported to be from three to six, but no final number yet).

MIRVing of Topol-M has long been somewhat of an obsession in Russia – there is a broad consensus among experts across the spectrum that this could compensate for the slow pace of the missile deployment, if only by artificially making the Russian forces look bigger. I think this belief is deeply misguided, but this is where the Russian debate stands.

The problem that has been holding back the a straightforward MIRVing of Topol-M was that it would violate one of the START Treaty provisions. The START Treaty prohibits “increasing the number of warheads attributed to an ICBM or SLBM of an existing or new type” (Article V.12d). Since for the purposes of the treaty Topol-M is just a “variant” of the Topol missile, Russia cannot simply declare that from a certain point Topol-M will be equipped with multiple warheads. To make MIRVing possible, Russia has to have a new missile, with multiple warheads attributed to it from the very beginning.

By saying that MIRVed Topol-M is a new missile, Russia has tried to avoid this conflict – RS-24 will apparently be declared as a new multiple-warhead missile. But there is a problem with that too – the treaty requires a “new type” missile to be substantially different from existing ones. This is how the treaty defines “new type”:

69. (59) The term "new type" means, for ICBMs or SLBMs, a type of ICBM or SLBM, the technical characteristics of which differ from those of an ICBM or SLBM, respectively, of each type declared previously in at least one of the following respects:

(a) number of stages;

(b) type of propellant of any stage;

(c) launch weight, by ten percent or more;

(d) length of either the assembled missile without front section, or length of the first stage, by ten percent or more;

(e) diameter of the first stage, by five percent or more; or

(f) throw-weight, by an increase of 21 percent or more, in conjunction with a change in the length of the first stage by five percent or more.

Here is the table from the latest START MOU that shows that Topol-M stays within these limits (footnotes are in the original):

Topol Topol-M silo Topol-M mobile
Number of stages 3 3 3
Length of assembled missile without front section, m 18.5 17.9 17.9
Maximum diameter of missile airframe (without stabilizers, raceways, lug guides, or other protruding elements), m 1.80 1.86 1.86
Launch weight [1], tonnes 45.1 47.2 47.2
Total length of missile as a unit with launch canister (with front section), m 22.3 22.7 22.3
Total length of missile as a unit with launch canister (without front section) [2], m


19.4 19.5
Length of launch canister body. m 20.0 19.4 19.5
Diameter of launch canister body (without protruding elements), m 2.00 1.95 2.05
First stage      
  Length. m 8.10 8.04 8.04
(6.5) [4]    
  Length used for confirming
  a new type [5], m
7.4 6.9 6.9
  Diameter, m 1.80 1.86 1.86
  Weight of fully loaded stage [1], tonnes 27.8 28.6 28.6
Second stage      
  Diameter (if different from first stage), m


1.61 1.61
Third stage      
  Diameter (if different from first stage), m


1.58 1.58
[1] Given as reference data; determined through calculation.
[2] As received from manufacturing plant.
[3] Without additional canister part (skirt) containing front section.
[4] Length of SS-25 ICBM first stage, burned without nozzle attached, is 6.5 m.
[5] Data will be provided when a new type of ICBM or SLBM is declared, for the purpose of confirming a change in the stage length of an ICBM or SLBM of a new type in comparison with the stage length of ICBMS or SLBMS of existing or previously declared new types.

This is not an accident, of course – the “new type” definition was designed to make sure that Topol-M can pretend to be a “variant” of Topol (which it is, in fact, not). But now this means that if RS-24 is not different from Topol-M, it cannot be legally considered a new missile.

I can see only one realistic option for RS-24 to be a new type missile – it has to have throw-weight that is larger than 1210 kg – more than 21 percent increase compared to Topol. Since it is less than one percent increase relative to the currently deployed Topol-M, it is probably doable. It would satisfy the requirement in paragraph (f), since the length of the first stage is already more than five percent different from that of Topol.

In fact, RS-24 may not even have to have larger throw-weight. At the moment, Russia can declare it as a prototype, which means it does not have to attribute a number of warheads or throw-weight to the missile until it is flight-tested at least 20 times or deployed. Since START is set to expire in December 2009, this means that Russia may avoid a conflict with the treaty by simply withholding the final throw-weight declaration until then.

This, of course, assumes that it is Topol, not Topol-M, that serves as a reference point. If this is not the case, RS-24 is most likely already in violation of the START Treaty. If its dimensions and weight are the same as those of Topol-M, as they apparently are, even withholding the throw-weight data under the prototype rule does not help – if the length of the first stage is not different by five percent, a missile cannot be considered new no matter what its throw-weight is. And the size and weight data should be reported right away.

We’ll have to wait until the July START MOU data are released in October to see what Russia has declared. In any event, the United States apparently decided not to challenge RS-24’s treaty compliance, probably finding the “prototype” explanation satisfactory. This is hardly surprising given that the U.S. administration has no intention to extend the treaty. A bit of a bad news here is that Russia is apparently has given up on the START Treaty extension as well. And it is not clear if the United States and Russia have what it takes to negotiate something meaningful to replace START.