Complex sentence: Udvar-Hazy is responsible for a US $65 million grant to the Smithsonian Institution that allowed the U.S. National Air and Space Museum to build the Steven F. Udvar-Hazy Center annex at Washington Dulles International Airport.
Split into simpler sentences: Udvar-Hazy is responsible for a US $65 million grant to the Smithsonian Institution. This allowed the U.S. National Air and Space Museum to build the Steven F. Udvar-Hazy Center annex at Washington Dulles International Airport.