A post about the SBX radar in armscontrolwonk.com (and especially the comments) reminded me that the radar is an interesting example of U.S.-Russian cooperation in missile defense, even though the cooperation was most likely an inadvertent one.
The floating platform for the radar, known as CS-50 or Moss Sirius, was built by the Vyborg shipbuilding plant in 2001-2002. Of course, the order for the construction did not come from the Missile Defense Agency. The Vyborg plant built the platform for Moss Maritime, a Norwegian company, for $35 million. The Norwegians then sold the platform to the U.S.
Shortly after the platform was built, in June 2002, the Vyborg plant announced that it got a contract for a second platform. It is not clear, though, if this one will be used in the U.S. missile defense program.