The AP is reporting that Russia has conducted a successful test-launch of its Bulava-class, submarine-launched ballistic missile (SLBM). A Navy spokesman in Moscow told the wire service that the missile hit its target on the Kamchatka Peninsula (in the Russian Far East), after being launched from a Typhoon-class ballistic missile sub in the White Sea.

Today’s successful test came after three previous launch failures of the Balava, which Russian President Vladimir Putin has described as a key component of his nation’s future nuclear forces. The Bulava is based on the SS-27 Topol M ICBM, which is already in service with Russia’s Strategic Rocket Forces, in both silo-based and mobile versions.

While development of the new missile will enhance Moscow’s strategic strike capabilities, the AP account ignores a critical fact: Russia’s fleet of ballistic missile subs (SSBNs) remains in serious disarry, and the number of available boats, crews (and missiles) is at–or near–an all-time low.

Over the past 20 years, the number of operational Russian SSBNs has decreased by 80%, the result of several factors, including disintegration of the former Soviet Union, subsequent economic woes (that limited defense funding), and political decisions that further curtailed the SSBN fleet.

Today, the Russian Navy has a total of six Delta III class ballistic missile subs (which entered service in the late 1970s and early 1980s); six Delta IV class SSBNs (that joined the fleet between 1985 and 1991), and one Typhoon-class sub (similar in size to the U.S. Ohio class), which dates from the 1980s. Russia’s only remaining Typhoon, the Dmitry Donskoi, served as the launch platform for today’s missile test.

But those numbers only tell part of the story. According to researchers at Stanford’s Center for International Security and Cooperation, two of the Delta IIIs are being decommissioned, and three of the Delta IVs are undergoing overhaul, a process that has been lengthened by funding shortfalls. That leaves Russia with only seven available SSBNs (four Delta IIIs, two Delta IVs and the single Typhoon. Some reports suggest that the Dimitry Donskoi will serve primarily as a test platform for the Bulava; if that’s correct, Moscow will have only six SSBNs over the near-term, divided between its Northern and Pacific Fleets.

But the remaining Delta IIIs are reaching the end of their service life, and the rest of those boats will also leave the fleet in the coming years. By the next decade, Russia’s SSBN force will be built largely around the remaining Delta IVs, all based in the Northern Fleet (which certainly simplifies our ASW efforts). Each Delta IV carries 15 SS-N-23 SLBMs, outfitted with up to four nuclear warheads. Additionally, the single Typhoon is expected to remain in service, and three Borey-class subs are also under construction.

However, development of the new SSBN has been slow. It took almost a decade to build the lead boat, largely due to funding issues. Construction of the second and third units in the Borey class is expected to progress more rapidly, but neither vessel is expected to enter service until after 2010. Addition of the Borey boats will give Russia as many as 10 SSBNs, depending on the status of the remaining Typhoon, and efforts to extend the service life of the Delta IVs.

By comparison, the U.S. ballistic sub force has also declined in recent years. Today, the U.S. Navy has 14 Ohio-class boats (each carrying 24 Trident D-5 SLBMs, with eight warheads per missile). Four other subs in the class have been converted into cruise missile platforms, each mounting up to 154 Tomahawks on each boat. And unlike their Russian counterparts, the U.S. subs have been well-maintained and fully-crewed, allowing the Navy to maintain a continuous SSBN presence. Beginning in the late 1990s, there were significant “gaps” in Russian SSBN patrols (particularly in the Pacific Fleet), with periods of several months between the return of one ballistic missile sub, and the departure of its replacement.

Conditions in the Russian SSBN fleet have improved slightly in recent years, but the relatively small number of boats–and retention of trained crew members–will make it more difficult for the Russians to sustain an effective, sea-based leg of its nuclear triad. Introduction of the Bulava missiles and Borey-class subs will provided a needed technological boost to the Russian fleet, and allow them to retain rough parity with the U.S., in terms of missiles and warheads.

But maintaining an adequate SSBN force requires more than new missiles and subs. It’s also a numbers game, measuring crew availability, days on patrol, and maintenance budgets. And it’s in those areas where the Russian fleet remains lacking, putting an even greater burden on land-based strategic systems for defense, deterrence and (possibly) a first-strike, under Moscow’s revised nuclear doctrine.