Defense Support Services, a joint venture of Lockheed Martin and Day & Zimmermann, provides support programs and resources to the Department of Defense at over 100 locations worldwide. Its areas of operation include ship operations and training, ground equipment maintenance, aircraft platforms, facility maintenance and operations. It supports a wide variety of combat and support units for the U.S. Army, Navy, Air Force and Marines and maintains weapon systems, aircrafts, ships and military vehicles. The services offered by the company include underway replenishment, offshore petroleum distribution, barge ferry operations, warehousing, transportation and building maintenance. Defense Support Services has offices located in Coronado, Calif.; Greenville, S.C.; and Mount Laurel, N.J.