The Russian Investigative Committee said on Tuesday it is probing workers at Russia's Federal Space Agency, Roscosmos, for negligence that may have caused the loss of three Glonass-M satellites in December.

The satellites, meant to conclude the formation of Russia's Glonass navigation system, were lost when a Proton-M carrier rocket veered off course and crashed in the Pacific Ocean.

"According to a preliminary investigation, Roscosmos workers equipped the carrier rocket with a new booster, which had not been thoroughly tested," Roscosmos spokesman Vladimir Markin said.

"The booster malfunctioned during the flight and deviated from the designated trajectory. The incident led to the loss of the satellites and cost the state 4.3 billion rubles ($152.2 million)."

Roscosmos declined to comment.

The rocket was equipped with a DM-3 booster, designed and manufactured by the Energia space corporation. In December Russian President Dmitry Medvedev dismissed Energia's chief rocket and space systems designer, Vyacheslav Filin, after a state commission investigating the incident found that the corporation's experts miscalculated how much fuel was needed for the DM-3 rocket booster.

Roscosmos head Anatoly Perminov was also reprimanded for not enforcing all the necessary pre-launch safety procedures and failing to spot the mistake in calculations.

Russia currently has 22 fully-operational Glonass satellites in orbit. The complete Glonass grouping must have 24 operational and 2-3 reserve satellites for the Glonass network to operate with global coverage. When complete, the project will be similar to the U.S.-made Global positioning system.

Another three Glonass-M satellites are planned to be launched in the third quarter of 2011 to complete the grouping.