Georgia Tech wants to double the size of its Marietta footprint by buying and renovating an additional 52 acres from Lockheed Martin for nearly $63 million. Georgia Tech officials pitched the project to the University System of Georgia’s Board of Regents on Tuesday. The proposal would expand its Cobb research facility to 104 acres. The expansion of the Georgia Tech Research Institute’s Cobb campus is expected to add about 500 jobs to the 300-or-so existing positions at the campus along Atlanta Road.