Complex sentence: Test launches with an upper stage mockup took place between 1973 and 1975, from Salto di Quirra.Italy at that time had developed its own nuclear weapons program and Alfa was part of it.
Split into simpler sentences: Test launches with an upper stage mockup took place between 1973 and 1975, from Salto di Quirra. At that time wad developed the Italian nuclear weapons program and Alfa was part of it.