Test launches of Russia's ill-fated Bulava ballistic missile will resume between August 9 and 12, a defense industry source said on Thursday.

"Preparations for the next test launch have been made. If the launch is a success, tests will be conducted more often," the source said, adding that at least three launches would be conducted before the end of the year.

A source close to the government commission probing the incident said last Friday the failure of the Bulava's latest test launch, from the Dmitry Donskoy nuclear submarine in the White Sea on December 9, 2009, was caused by a defective engine nozzle.

After this, all further Bulava test launches were put on hold pending the results of a government investigation.

The source said it was not a design but a manufacturing fault.

"It was simply that the missile wasn't built right," he said.

The Bulava (SS-NX-30), a three-stage liquid and solid-propellant submarine-launched ballistic missile (SLBM), has officially suffered seven failures in 12 tests.

Some analysts suggest that in reality the number of failures is considerably larger. Russian military expert Pavel Felgenhauer says only one of the 12 launches has been an outright success.

The future development of the Bulava has been questioned by several lawmakers and defense industry officials, who suggest that all efforts should be focused on the existing Sineva SLBM.

However, that would require major changes to the Borey-class submarines. The Russian military has insisted that there is no alternative to the Bulava and pledged to continue testing the missile until it is ready to be put into service with the Navy.

MOSCOW, July 29 (RIA Novosti)