In June 1957 the design of G-159 was finalised and Grumman started selling slots on the production line at $10,000 each.The Gulfstream I is a low-wing cantilever monoplane with a semi-monocoque aluminium alloy fuselage structure.The aircraft is powered by two Rolls-Royce Dart turboprops with Rotol four-bladed constant speed propellers.The cabin is designed to take up to twenty-four passengers in a high-density arrangement or only eight in an executive layout, although ten to twelve was more usual.A single Gulfstream I was delivered to the United States Coast Guard (USCG) in 1963, outfitted as an executive transport and designated the VC-4A.NASA, the U.S. space agency, flew the Gulfstream I as a passenger transport aircraft and operated seven G-Is.