Yoyodyne Division (also known as Yoyodyne Propulsion Systems) was a company involved in starship construction at shipyards across the Federation. Facilities Yoyodyne Propulsion Systems worked out of included 40 Eridani A Starfleet Construction Yards, Copernicus Ship Yards and San Francisco Fleet Yards. Offices were also located throughout the Federation, including an office on Deep Space 9's Promenade. (Star Trek: The Next Generation; Star Trek: Deep Space Nine) Some Starfleet starships Yoyodyne were involved in constructing included the: