Defense contractor Northrop Grumman has begun moving secret cargo through a Southern California marina this weekend. The large object will be taken from a Northrop Grumman facility in Redondo Beach to a barge for shipment to San Diego. Northrop Grumman officials cited national security concerns in declining to provide information about the object. The company agreed on Oct. 15 to pay the city $25,000 for a licensing agreement to use the marina and for any costs the city incurs.