Editing Falcon 1 (section)

== Design ==
According to SpaceX, the Falcon 1 was designed to minimize price per launch for [[low Earth orbit|low-Earth-orbit]] [[satellite]]s, increase reliability, and optimize flight environment and time to launch.<ref name="SpaceX Falcon1">{{cite web|url=http://www.spacex.com/falcon1.php |publisher=SpaceX |title=Falcon 1 Overview |access-date=May 5, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20120118140101/http://www.spacex.com/falcon1.php |archive-date=January 18, 2012 }}</ref> It also was used to verify components and structural design concepts that would be reused in the [[Falcon 9]]. SpaceX started with the idea that the smallest useful orbital rocket was the [[minimum viable product]] (Falcon 1 with about {{cvt|450|kg|disp=or|lb}} to orbit), instead of building something larger and more complicated, and then running out of money and going bankrupt.<ref>Dead link: {{cite web|url=https://www.youtube.com/watch?v=ab2VVp1GfmA|title=YouTube|website=Youtube.com|access-date=August 18, 2017}}{{cbignore}}{{Dead Youtube links|date=February 2022}}</ref>{{Citation needed|date=February 2022}} [[Image:SpaceX falcon in warehouse.jpg|thumb|left|First-stage view of the [[Merlin (rocket engine)|Merlin]] engine.]]
=== 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/>

=== 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/>

=== Reusability ===
The first stage was originally planned to return by [[parachute]] to a water landing and be recovered for reuse, but this capability was never demonstrated.<ref name="Ruese">{{cite press release|url=http://www.spacex.com/press.php?page=18|title=SpaceX Announces the Falcon 9 Fully Reusable Heavy Lift Launch Vehicle|last=Brown|first=Mary Beth|date=September 8, 2005|publisher=[[SpaceX]]|access-date=November 4, 2009|location=El Segundo, CA|archive-url=https://web.archive.org/web/20130326183411/http://www.spacex.com/press.php?page=18|archive-date=March 26, 2013|url-status=dead}}</ref><ref name="SFN-F4">{{cite web|url=http://spaceflightnow.com/falcon/004/|title=Sweet success at last for Falcon 1 rocket|last=Clarke|first=Stephen|date=September 28, 2008|publisher=Spaceflight Now|access-date=November 4, 2009}}</ref> The second stage was not designed to be reusable.<ref name="Ruese" /><ref name="SFN-F4" />

=== Launch sequence ===
At launch, the first stage engine (Merlin) is ignited and throttled to full power while the launcher is restrained and all systems are verified by the flight computer. If the systems are operating correctly, the rocket is released and clears the tower in about seven seconds. The first-stage burn lasts about 2 minutes and 49 seconds. Stage separation is accomplished with [[explosive bolts]] and a pneumatically actuated pusher system.{{cn|date=September 2018}} The second stage Kestrel engine burns for about six minutes, inserting the payload into a low Earth orbit. It is capable of multiple restarts.{{cn|date=September 2018}}