Editing Atlas II (section)

{{Short description|American rocket}}
{{Use mdy dates|date=June 2019}}
{{Infobox rocket
|image = DF-SC-99-00074 cropped and rotated.jpeg
|caption = Launch of an Atlas II rocket
|name = Atlas II
|function = [[Medium-lift launch vehicle]]
|manufacturer = [[Lockheed Martin]]
|country-origin = United States
|height = {{convert|47.54|m|ft|abbr=on}}
|diameter = {{convert|3.04|m|ft|abbr=on}}
|mass = {{convert|204,300|kg|lb|abbr=on}}
|stages = 2.5 (3.5 with [[Integrated Apogee Boost Stage|IABS]])
<!----Payloads (optional)---->
|capacities = 
  {{Infobox rocket/payload
  |location =  [[Low Earth orbit|LEO]]
  |kilos    =  {{plainlist|
* '''Atlas II''': {{cvt |6,580|kg|lb}}
* '''Atlas IIA''': {{cvt|7,280|kg|lb}}
* '''Atlas IIAS''': {{cvt|8,610|kg|lb}}<ref name=astronautixAtlasII />
    }}
  }}
  {{Infobox rocket/payload
  |location =  [[Geostationary transfer orbit|GTO]]
  |kilos    =  {{plainlist|
* '''Atlas II''': {{cvt |2,810|kg|lb}}
* '''Atlas IIA''': {{cvt|3,039|kg|lb}}
* '''Atlas IIAS''': {{cvt|3,630|kg|lb}}<ref name=astronautixAtlasII />
    }}
  }}
|family = [[Atlas (rocket family)|Atlas]]
|status = Retired
|sites = [[Cape Canaveral Space Force Station|Cape Canaveral]], [[Cape Canaveral Launch Complex 36|LC-36]]<br /> [[Vandenberg Space Force Base|Vandenberg]], [[Vandenberg Space Launch Complex 3|SLC-3]]
|launches = 63 ('''II:'''&nbsp;10, '''IIA:'''&nbsp;23, '''IIAS:'''&nbsp;30)
|success = 63
|fail =
|partial =
|first='''II:''' December 7, 1991<br />'''IIA:''' June 10, 1992<br />'''IIAS:''' December 16, 1993
|last='''II:''' March 16, 1998<br />'''IIA:''' December 5, 2002<br />'''IIAS:''' August 31, 2004<ref name="final">Tariq Malik [http://www.space.com/296-final-atlas-2-rocket-orbits-classified-satellite.html "Final Atlas 2 Rocket Orbits Classified U.S. Satellite"], ''Space News,'' August 31, 2004 (Accessed September 24, 2014)</ref>
|payloads = [[Solar and Heliospheric Observatory|SOHO]] (Atlas IIAS)<br />[[Tracking and Data Relay Satellite|TDRS]] (Atlas IIA)
| stagedata= 
{{Infobox rocket/stage
  |type       = stage
  |stageno    = First
  |engines    = 1 × [[RS-56]]-OSA
  |thrust     = {{cvt|386|kN}}
  |SI         = {{cvt|316|isp}}
  |burntime   = 283 seconds
  |fuel       = [[RP-1]] / [[LOX]]
  }}
{{Infobox rocket/stage
  |type       =  booster
  |name       =  [[MA-5A]]
  |number     =  2
  |engines    =  1 × [[RS-56]]-OBA
  |thrust     =  
  |total      =  {{cvt|2,093.3|kN}}
  |SI         =  {{cvt|299|isp}}
  |burntime   =  172 seconds
  |fuel       =  [[RP-1]] / [[LOX]]
  }}
{{Infobox rocket/stage
  |type       =  booster
  |diff       =  Atlas IIAS only
  |name       =  [[Castor (rocket stage)|Castor 4A]]
  |number     =  4
  |solid      =  yes
  |thrust     =  {{cvt|433.7|kN}}
  |total      =  {{cvt|1734.8|kN}}
  |SI         =  {{cvt|237.8|isp}}
  |burntime   =  56 seconds
  |fuel       =  [[Hydroxyl-terminated polybutadiene|HTPB]]<ref>{{cite web |last1=Wade |first1=Mark |title=Castor 4A engine |url=http://www.astronautix.com/c/castor4aengine.html |archive-url=https://web.archive.org/web/20161228152826/http://astronautix.com/c/castor4aengine.html |url-status=dead |archive-date=December 28, 2016 |website=astronautix.com}}</ref>
  }}
{{Infobox rocket/stage
  |type       = stage
  |stageno    = Second
  |name       = [[Centaur (rocket stage)|Centaur II]]
  |engines    = 2 × [[RL-10]]A
  |thrust     = {{cvt|147|kN}}
  |SI         = {{cvt|449|isp}}
  |burntime   = 392 seconds
  |fuel       = [[Liquid hydrogen|LH{{sub|2}}]] / [[LOX]]
  }}
{{Infobox rocket/stage
  |type       = stage
  |stageno    = Third
  |name       = [[Integrated Apogee Boost Stage|IABS]] 
  |diff       = optional
  |engines    = 2 × [[R-4D]]
  |thrust     = {{cvt|980|N}}
  |SI         = {{cvt|312|isp}}
  |burntime   = 60 seconds
  |fuel       = [[N2O4|N{{sub|2}}O{{sub|4}}]] / [[Monomethylhydrazine|MMH]]
  }}
}}

'''Atlas II''' was a member of the [[Atlas (rocket family)|Atlas]] family of [[launch vehicle]]s, which evolved from the successful [[Atlas missile]] program of the 1950s. The Atlas&nbsp;II was a direct evolution of the [[Atlas&nbsp;I]], featuring longer first-stage tanks, higher-performing engines, and the option for strap-on solid rocket boosters. It was designed to launch payloads into [[low Earth orbit]], geosynchronous transfer orbit or geosynchronous orbit. Sixty-three launches of the Atlas&nbsp;II, IIA and IIAS models were carried out between 1991 and 2004; all sixty-three launches were successes, making the Atlas&nbsp;II a highly reliable space launch system. The Atlas line was continued by the [[Atlas&nbsp;III]], used between 2000 and 2005, and the [[Atlas&nbsp;V]], which is still in use {{as of|2024|lc=y}}.