Editing SpaceX Merlin (section)

===Merlin 1C===
{{Infobox rocket engine
| name                       = Merlin 1C
| country_of_origin          = [[United States]]
| manufacturer               = [[SpaceX]]
| purpose                    = {{plainlist|
* [[Booster (rocketry)|Booster stage]] engines
* [[Upper stage]] engine
}}
| associated                 = [[Falcon 1]], [[Falcon 9]]
| status                     = Retired
| type                       = liquid
| oxidiser                   = [[LOX]]
| fuel                       = [[RP-1]]
| cycle                      = [[Gas-generator cycle|Gas-generator]]
| thrust(Vac)                = {{nowrap| {{cvt|480|kN}}<ref name="BWire_Regen"/> }}
| thrust(SL)                 = {{cvt|420|kN}}<ref name="BWire_Regen">{{cite news |url=http://home.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20071112005019&newsLang=en |title=SpaceX Completes Development of Merlin Regeneratively Cooled Rocket Engine |publisher=Business Wire |date=November 13, 2007 |access-date=November 12, 2007 |archive-date=January 3, 2008 |archive-url=https://web.archive.org/web/20080103164100/http://www.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view |url-status=live }}</ref>
| throttle_range             = 
| thrust_to_weight           = 96
| chamber_pressure           = {{cvt|6.77|MPa|psi}}<ref name="NSPO"/>
| specific_impulse_vacuum    = {{cvt|304.8|isp}}<ref name="NSPO">{{cite conference |url=http://www2.nspo.org.tw/ASC2008/4th%20Asian%20Space%20Conference%202008/oral/S12-11.pdf |title=Low-cost Launch Opportunities Provided by the Falcon Family of Launch Vehicles |conference=Fourth Asian Space Conference |location=Taipei |first1=Aaron |last1=Dinardi |first2=Peter |last2=Capozzoli |first3=Gwynne |last3=Shotwell |year=2008 |archive-url=https://web.archive.org/web/20120315135217/http://www2.nspo.org.tw/ASC2008/4th%20Asian%20Space%20Conference%202008/oral/S12-11.pdf |archive-date=March 15, 2012 |url-status=dead}}</ref>
| specific_impulse_sea_level = {{cvt|275|isp}}
| length                     = {{cvt|2.92|m}}<ref name="iacse.commercial-space.net">{{cite web |url=http://iacse.commercial-space.net/wp-content/uploads/2008/10/iac-08d213.pdf |title=The SpaceX Falcon 1 Launch Vehicle Flight 3 Results, Future Developments, and Falcon 9 Evolution |access-date=December 29, 2012 |archive-date=March 4, 2016 |archive-url=https://web.archive.org/web/20160304062239/http://iacse.commercial-space.net/wp-content/uploads/2008/10/iac-08d213.pdf |url-status=live }}</ref>
| diameter                   = 
| dry_weight                 = {{cvt|1380|lb|kg|order=flip}}
}}

[[File:SpaceX factory Merlin engine.jpg|thumb|left|Merlin 1C under construction at SpaceX]]
Three versions of the '''Merlin 1C''' engine were produced. The Merlin engine for Falcon&nbsp;1 had a movable turbopump exhaust assembly, which was used to provide roll control by vectoring the exhaust. The Merlin&nbsp;1C engine for the Falcon&nbsp;9 first stage is nearly identical to the variant used for the Falcon&nbsp;1, although the turbopump exhaust assembly is not movable. Finally, a Merlin&nbsp;1C [[vacuum]] variant is used on the Falcon&nbsp;9 second stage. This engine differs from the Falcon&nbsp;9 first-stage variant in that it uses a larger exhaust nozzle optimized for vacuum operation and can be throttled between 60% and 100%.<ref name="NSPO"/>

The Merlin 1C uses a [[Regenerative cooling (rocket)|regeneratively cooled]] nozzle and combustion chamber. The turbopump used is a Merlin&nbsp;1B model with only slight alterations. It was fired with a full mission duty firing of 170&nbsp;seconds in November 2007,<ref name="BWire_Regen"/> first flew on a [[List of Falcon 1 launches#Third flight|mission]] in August 2008,<ref name="sfn20080928"/> powered the "first [[private spaceflight|{{Sic|hide=y|privately|-}}developed]] liquid-fueled rocket to successfully reach orbit", [[Falcon&nbsp;1 Flight&nbsp;4]], in September 2008,<ref name="sfn20080928">{{cite web |last=Clark |first=Stephen |title=Sweet Success at Last for Falcon 1 Rocket |date=September 28, 2008 |publisher=Spaceflight Now |url=http://www.spaceflightnow.com/falcon/004/index.html |access-date=April 6, 2011 |quote=the first {{Sic|hide=y|privately|-}}developed liquid-fueled rocket to successfully reach orbit |archive-date=September 24, 2015 |archive-url=https://web.archive.org/web/20150924182644/http://www.spaceflightnow.com/falcon/004/index.html |url-status=live }}</ref> and powered the [[Falcon 9 Flight 1|Falcon&nbsp;9 on its maiden flight]] in June 2010.<ref name="msnbc20100604">{{cite news |last=Boyle |first=Alan |title=Shuttle successor succeeds in first test flight |url=http://www.nbcnews.com/id/37509776 |access-date=June 5, 2010 |newspaper=[[NBC News]] |date=June 4, 2010 |archive-date=December 21, 2019 |archive-url=https://web.archive.org/web/20191221015812/http://www.nbcnews.com/id/37509776 |url-status=dead }}</ref>

As configured for use on Falcon 1 vehicles, the Merlin&nbsp;1C had a sea-level thrust of {{cvt|78000|lbf|kN|order=flip}}, a vacuum thrust of {{cvt|90000|lbf|kN|order=flip}} and a vacuum [[specific impulse]] of {{cvt|304|isp|km/s}}. In this configuration, the engine consumed {{cvt|300|lb|kg|order=flip}} of propellant per second. Tests have been conducted with a single Merlin&nbsp;1C engine successfully running a total of 27&nbsp;minutes (counting together the duration of the various tests), which equals ten complete [[Falcon&nbsp;1]] flights.<ref name="v11rO">{{cite press release |url=http://www.spacex.com/press/2012/12/19/spacex-completes-qualification-testing-merlin-regeneratively-cooled-engine |title=SpaceX Completes Qualification Testing of Merlin Regeneratively Cooled Engine |publisher=SpaceX |date=February 25, 2008 |access-date=May 31, 2016 |archive-date=August 22, 2016 |archive-url=https://web.archive.org/web/20160822175301/http://www.spacex.com/press/2012/12/19/spacex-completes-qualification-testing-merlin-regeneratively-cooled-engine |url-status=live }}</ref> The Merlin&nbsp;1C chamber and nozzle are cooled [[Regenerative cooling (rocketry)|regeneratively]] by {{cvt|100|lb|order=flip}} per second of kerosene flow and are able to absorb {{cvt|10|MW}} of [[heat energy]].<ref name="sxua200712">{{cite web |title=Updates: December 2007 |archive-url=https://web.archive.org/web/20130405083840/http://www.spacex.com/updates_archive.php?page=121007 |archive-date=April 5, 2013 |url-status=dead |url=http://www.spacex.com/updates_archive.php?page=121007 |date=Dec 2007 |work=Updates Archive |publisher=SpaceX |access-date=December 27, 2012 |quote=(2007:) Merlin has a thrust at sea level of 95,000&nbsp;lbs, a vacuum thrust of over 108,000&nbsp;pounds, vacuum specific impulse of 304&nbsp;seconds and sea level thrust to weight ratio of 92. In generating this thrust, Merlin consumes 350&nbsp;lbs/second of propellant and the chamber and nozzle, cooled by 100&nbsp;lbs/sec of kerosene, are capable of absorbing 10&nbsp;MW of heat energy. A planned turbo pump upgrade in 2009 will improve the thrust by over 20% and the thrust to weight ratio by approximately 25%.}}</ref>

A Merlin 1C was first used as part of the unsuccessful third attempt to launch a Falcon&nbsp;1. In discussing the failure, Elon Musk noted: "The flight of our first stage, with the new Merlin&nbsp;1C engine that will be used in Falcon&nbsp;9, was picture perfect."<ref name="Mwo6O">{{cite web |url=http://www.nasaspaceflight.com/2008/08/spacex-falcon-i-fails-during-first-stage-flight/ |title=SpaceX Falcon I fails during first stage flight |first=Chris |last=Bergin |author2=Davis, Matt |date=August 2, 2008 |publisher=NASAspaceflight |access-date=February 26, 2010 |archive-date=March 3, 2016 |archive-url=https://web.archive.org/web/20160303210834/http://www.nasaspaceflight.com/2008/08/spacex-falcon-i-fails-during-first-stage-flight/ |url-status=live }}</ref> The Merlin&nbsp;1C was used in the successful [[Ratsat|fourth flight]] of Falcon&nbsp;1 on September 28, 2008.<ref name="MSC">{{cite web |url=http://www.spaceflightnow.com/falcon/004/ |title=Sweet success at last for Falcon 1 rocket |last=Clark |first=Stephen |date=September 28, 2008 |publisher=Spaceflight Now |access-date=September 28, 2008 |archive-date=March 3, 2016 |archive-url=https://web.archive.org/web/20160303211418/http://www.spaceflightnow.com/falcon/004/ |url-status=live }}</ref>

On October 7, 2012, a Merlin 1C (Engine No.&nbsp;1) of the [[SpaceX CRS-1|CRS-1]] mission experienced an [[SpaceX CRS-1#Falcon 9 engine anomaly|anomaly]] at T+00:01:20, which appears on [https://www.youtube.com/watch?v=tRTYh71D9P0 CRS-1 launch video] as a flash. The failure occurred just as the vehicle achieved max-Q (maximum aerodynamic pressure). SpaceX's internal review found that the engine was shut down after a sudden pressure loss and that only the aerodynamic shell was destroyed, generating the debris seen in the video; the engine did not explode, as SpaceX ground control continued to receive data from it throughout the flight. The primary mission was unaffected by the anomaly due to the nominal operation of the remaining eight engines and an onboard readjustment of the flight trajectory,<ref name="cQ3yS">{{cite web |last=Nelson |first=Katherine |title=SpaceX CRS-1 Mission Update |url=http://www.spacex.com/press/2012/12/19/spacex-crs-1-mission-update |publisher=SpaceX |date=October 8, 2012 |access-date=May 31, 2016 |archive-date=April 12, 2017 |archive-url=https://web.archive.org/web/20170412004145/http://www.spacex.com/press/2012/12/19/spacex-crs-1-mission-update |url-status=live }}</ref> but the secondary-mission payload failed to reach its target orbit due to safety protocols in place to prevent collisions with the ISS. These protocols prevented a second firing of the upper stage for the secondary payload.<ref name="sfn20121011">{{cite web |url=http://www.spaceflightnow.com/falcon9/004/121011orbcomm/ |title=Orbcomm craft falls to Earth, company claims total loss |publisher=Spaceflight Now |first=Stephen |last=Clark |access-date=October 11, 2012 |date=October 11, 2012 |archive-date=March 15, 2016 |archive-url=https://web.archive.org/web/20160315001856/http://spaceflightnow.com/falcon9/004/121011orbcomm/ |url-status=live }}</ref>

SpaceX was planning to develop a {{cvt|560|kN|lbf}} version of Merlin&nbsp;1C to be used in Falcon&nbsp;9 Block&nbsp;II and Falcon&nbsp;1E boosters.<ref name="ltDQy">{{cite web |archive-url=https://web.archive.org/web/20121002181416/http://www.spacex.com/Falcon1UsersGuide.pdf |archive-date=October 2, 2012 |url-status=dead |url=http://www.spacex.com/Falcon1UsersGuide.pdf |title=Falcon 1 Users Guide (Rev 7) |publisher=SpaceX |date=August 26, 2008 |page=8}}</ref> This engine and these booster models were dropped in favor of the more advanced Merlin&nbsp;1D engine and longer Falcon&nbsp;9&nbsp;v1.1 booster.[[File:Merlin 1C Vacuum engine at Hawthorne factory (2008).jpg|thumb|left|upright=0.6|Merlin 1C Vacuum engine at Hawthorne factory in 2008]]