Editing Falcon 1 (section)

=== First stage ===
The first stage was made from [[friction stir welding|friction-stir-welded]] [[2219 aluminium alloy|2219]] [[aluminum]] [[alloy]].<ref name=ssc200708>
{{cite journal |last=Bjelde|first=Brian |author2=Max Vozoff|author3=Gwynne Shotwell |title=The Falcon 1 Launch Vehicle: Demonstration Flights, Status, Manifest, and Upgrade Path |journal=21st Annual AIAA/USU Conference on Small Satellites |date=August 2007 |issue=SSC07 – III – 6 |url=http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1456&context=smallsat |access-date=December 6, 2013 }}</ref> It employs a common bulkhead between the LOX and RP-1 tanks, as well as flight pressure stabilization. It can be transported safely without pressurization (like the heavier [[Delta II]] isogrid design) but gains additional strength when pressurized for flight (like the [[Atlas II]], which could not be transported unpressurized). The parachute system, built by Irvin Para&shy;chute Corp&shy;oration, uses a high-speed [[drogue chute]] and a main chute.

For the first two launches, the Falcon 1 used a Merlin 1A engine. An improved version of the Merlin 1A, the Merlin 1B, was supposed to fly on later flights of the Falcon 1, although it was further improved to create the Merlin 1C, which was first flown on the third Falcon 1 flight, and on the first 5 flights of the Falcon 9. The Falcon 1 first stage was powered by a single [[Pump-fed engine|pump-fed]] [[Merlin 1C]] engine burning [[RP-1]] and [[liquid oxygen]] providing {{convert|92000|lbf|kN|order=flip}} of sea-level thrust and a specific impulse of 245 s (vacuum I<sub>sp</sub> 290 s).<ref name=ssc200708/>  The first stage burns to depletion, taking around 169 seconds to do so.<ref name=ssc200708/>