The Bulava submarine-launched ballistic missile (SLBM) has officially suffered seven failures in 12 tests. Some analysts suggest that in reality the number of failures was considerably larger, with Russian military expert Pavel Felgenhauer contending that of the Bulava's 12 test launches, only one was entirely successful. "So far the Bulava tests have not been very successful, but we are looking for the causes [of the failures] and working to rectify them, and we will definitely bring this work to conclusion," Serdyukov said.