To accommodate production of its new airliner, Boeing doubled the size of the Everett factory at the cost of nearly US$1.5 billion to provide space for two new assembly lines. New production methods were developed, including a turn machine that could rotate fuselage subassemblies 180 degrees, giving workers access to upper body sections. Major assembly of the first aircraft began on January 4, 1993. By the start of production, the program had amassed 118 firm orders, with options for 95 more from 10 airlines. Total investment in the program was estimated at over US$4 billion from Boeing, with an additional US$2 billion from suppliers.