Falcon 9 Air

Falcon 9 Air was an air-launched multi-stage launch vehicle under development by SpaceX in 2011-2012. Falcon 9 Air was to be carried to launch position and launch altitude by a Stratolaunch Systems carrier aircraft, the world's largest aircraft by wingspan. Payload to low Earth orbit was projected to be 6,100 kg (13,400 pounds).

Propulsion for the rocket was planned to be provided by four Merlin 1D rocket engines, engines that were also to be used in the Falcon 9 v1.1 beginning in 2013, and also on the Falcon Heavy in 2014. First flight for the air-launched Falcon 9 Air rocket was notionally planned for 2016.

Development ceased in 4Q2012 as SpaceX and Stratolaunch "amicably agreed to end [their] contractual relationship because the [Stratolaunch] launch vehicle design [had] departed significantly from the Falcon derivative vehicle envisioned by SpaceX and does not fit well with [SpaceX's] long-term strategic business model."

In December 2011 Stratolaunch Systems announced that it would contract with SpaceX to develop an air-launched, multiple-stage launch vehicle, as a derivative of Falcon 9 technology, called the Falcon 9 Air, as part of the Stratolaunch project. As initially conceived with the SpaceX Falcon 9 Air (F9A) launch vehicle, Stratolaunch was to initially place satellites of up to 6,100 kg (13,400 pounds) into low Earth orbit; and once established as a reliable system, announced that it would explore a human-rated version. The system can take-off from airfields with a minimum 3,700 m (12,100 feet) length, and the F9A carrier aircraft was proposed to travel to a launch point up to 2,200 km (1,200 nautical miles) away from the airfield and fly at a launch altitude of 9,100 m (30,000 feet).

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