Editing Delta IV (section)

== Delta IV Medium ==
The Delta IV Medium (also referred to as 'single stick'<ref>{{Cite web |last=Clark |first=Stephen |title=Final 'single stick' Delta 4-Medium rocket arrives at Florida launch pad – Spaceflight Now |url=https://spaceflightnow.com/2019/06/07/final-single-stick-delta-4-medium-rocket-arrives-at-florida-launch-pad/ |access-date=2020-11-01 |language=en-US}}</ref><ref>{{Cite web |last=Ray |first=Justin |title=Air Force assigns new Delta 4 rocket launch – Spaceflight Now |url=https://spaceflightnow.com/2015/09/10/air-force-assigns-new-delta-4-rocket-launch/ |access-date=2020-11-01 |language=en-US}}</ref>) was available in four configurations: Medium, Medium+ (4,2), Medium+ (5,2), and Medium+ (5,4).<ref name="NASA-SF_Last_med_DIV">{{Cite web |last=Gebhardt |first=Chris |date=2019-08-22 |title=Delta IV Medium's well-earned retirement with GPS finale |url=https://www.nasaspaceflight.com/2019/08/delta-iv-medium-retirement-gps-finale/ |access-date=2020-08-15 |publisher=NASASpaceFlight.com}}</ref>

The Delta IV Medium (Delta 9040) was the most basic Delta IV. It featured a single CBC and a modified [[Delta III]] second stage, with 4-meter liquid hydrogen and liquid oxygen tanks (called a [[Delta Cryogenic Second Stage]] (DCSS)) and a 4-meter payload fairing. The Delta IV Medium was capable of launching 4,200&nbsp;kg to [[geostationary transfer orbit]] (GTO). From Cape Canaveral, GTO is 1804&nbsp;m/s away from GEO. The mass of fairing and payload attach fittings have been subtracted from the gross performance.<ref name="planner guide2013">{{Cite web |date=June 2013 |title=Delta IV Launch Services User's Guide |url=http://www.ulalaunch.com/uploads/docs/Launch_Vehicles/Delta_IV_Users_Guide_June_2013.pdf |url-status=dead |archive-url=https://web.archive.org/web/20140710005717/http://www.ulalaunch.com/uploads/docs/Launch_Vehicles/Delta_IV_Users_Guide_June_2013.pdf |archive-date=2014-07-10 |access-date=2014-07-09 |publisher=United Launch Alliance |pages=2–10, 5-3}}</ref>

The Delta IV Medium+ (4,2) (Delta 9240) had the same CBC and DCSS as the Medium, but with the addition of two [[Orbital ATK]]-built 1.5-m (60-in) diameter [[solid rocket booster]] [[Graphite-Epoxy Motor]]s (GEM 60s) [[strap-on booster]]s to increase payload capacity to 6,150&nbsp;kg to GTO.<ref name="planner guide2013" />

The Delta IV Medium+ (5,2) (Delta 9250) was similar to the Medium+ (4,2), but had a 5-m–diameter DCSS and payload fairing for larger payloads. Because of the extra weight of the larger payload fairing and second stage, the Medium+ (5,2) could launch 5,072&nbsp;kg to GTO.<ref name="planner guide2013" />

The Delta IV Medium+ (5,4) (Delta 9450) was similar to the Medium+ (5,2), but used four GEM 60s instead of two, enabling it to lift 6,882&nbsp;kg to GTO.<ref name="planner guide2013" />

To encapsulate the satellite payload, a variety of different payload fairings were available. A stretched Delta III 4-meter diameter composite payload fairing was used on 4-meter Medium versions, while an enlarged, 5-meter diameter composite fairing was used on 5-meter Medium versions.<ref name=DeltaIVpayloadplanner/>

The Medium (4,2) version last flew on 22 August 2019, marking the retirement of the Delta IV Medium variants.<ref name="NASA-SF_Last_med_DIV" /><ref>{{Cite web |last=Berger |first=Eric |date=2019-08-22 |title=The last single-stick Delta rocket launched Thursday, and it put on a show |url=https://arstechnica.com/science/2019/08/the-last-single-stick-delta-rocket-launched-thursday-and-it-put-on-a-show/ |access-date=2020-08-06 |publisher=Ars Technica}}</ref>