Complex sentence: About US $6.9 billion had already been invested in the Comanche program at the time of its termination and an additional US $450-680 million was required in contract termination fees to main program partners Sikorsky and Boeing Integrated Defense Systems.
Split into simpler sentences: About US $6.9 billion had already been invested in the Comanche program at the time of its termination. An additional US $450-680 million was required in contract termination fees to main program partners Sikorsky and Boeing Integrated Defense Systems.