Editing Falcon 1 (section)

=== Second stage ===
The second stage Falcon 1 tanks were built with a [[cryogenic]]-compatible [[2014 aluminum alloy]],<ref name=ssc200708/>
with the plan to move to [[2195 aluminum alloy|aluminum-lithium alloy]] on the Falcon 1e.<ref name=ssc200708/>
The [[helium]] pressurization system pumps propellant to the engine, supplies heated<ref name=ssc200708/> pressurized gas for the attitude control thrusters, and is used for zero-''g'' [[ullage engine|propellant accumulation]] prior to engine restart. The [[Kestrel (rocket engine)|Kestrel]] engine includes a titanium heat exchanger to pass waste heat to the helium, thereby greatly extending its work capacity.<ref>{{cite web|url=http://www.spacex.com/SpaceX_F1-003_PressKit.pdf |publisher=SpaceX |title=Falcon 1 Flight Three Press Kit |access-date=September 30, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20081001161901/http://www.spacex.com/SpaceX_F1-003_PressKit.pdf |archive-date=October 1, 2008 }}</ref> 
The pressure tanks are [[composite overwrapped pressure vessels]] made by Arde corporation with [[inconel]] alloy and are the same as those used in the [[Delta IV rocket|Delta III]].<ref>{{cite web|title=Falcon 1|url=http://www.astronautix.com/f/falcon1.html|website=Encyclopedia Astronautica|publisher=Space Daily|access-date=November 25, 2022}}</ref>

The second stage was powered by a [[Pressure-fed engine (rocket)|pressure-fed]] [[Kestrel (rocket engine)|Kestrel]] engine with {{convert|7000|lbf|kN|order=flip}} of vacuum thrust and a vacuum specific impulse of 330 s.<ref name=ssc200708/>