Acterna, a Germantown telecommunications company, plans to consolidate its 4,000 employees, currently situated at five Germantown locations, at a new 45-acre corporate campus at the Milestone site in Germantown. Current plans include two initial buildings totaling 280,000 sf, with a potential for 700,000 sf at final build-out. The Peterson Cos., based in Fairfax, Va., is developing the property.