Delta II
421565
224292780
2008-07-08T05:15:09Z
Tanveer.bhuiyan
4106417
{{dablink|This article is about the rocket. For the submarine see [[Delta class submarine]].}}
{{Infobox rocket
|name = Delta II
|image = Delta II Dawn liftoff 1.jpg
|caption = A Delta II rocket launches from [[Cape Canaveral Air Force Station|Cape Canaveral]] carrying the [[Dawn (spacecraft)|Dawn]] spacecraft.
|function = [[Launch vehicle]]
|manufacturer = [[United Launch Alliance]] ([[Boeing]] [[Boeing Integrated Defense Systems|IDS]])
|country-origin = [[United States]]
|cpl-year = 1987
|cpl = $36.7m (USD)
|height = 38.2 - 39 [[metre|m]]
|alt-height = 125.3 - 127 [[foot (unit)|ft]]
|diameter = 2.44 m
|alt-diameter = 8 ft
|mass = 151,700 - 231,870 [[kg]]<br>
|alt-mass =334,300 - 511,180 [[pound (mass)|lb]]
|stages = 2 or 3
|LEO-payload = 2,700 - 6,100 kg <br> (5,960 - 13,440 lb)
|payload-location = [[Geostationary transfer orbit|GTO]]
|payload = 900 - 2,170 kg <br> (1,980 - 4,790 lb)
|payload-location2 = [[Escape trajectory|Escape]]
|payload2 = 1,000 kg
|status = Active
|sites = [[Cape Canaveral Air Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Launch Complex 17|LC-17]]<br>[[Vandenberg AFB]] [[Vandenberg AFB Space Launch Complex 2|SLC-2W]]
|first =Delta 6000: [[14 February]] [[1989]]<br>Delta 7000: [[26 November]] [[1990]]<br>Delta 7000H: [[8 July]] [[2003]]
|last = Delta 6000: [[24 July]] [[1992]] <!--Others have not retired yet. -->
|launches = 136<br>Delta 6000: 17<br>Delta 7000: 114<br>Delta 7000H: 5
|success = 134<br>Delta 6000: 17<br>Delta 7000: 112<br>Delta 7000H: 5
|fail = 1 (Delta 7000)
|partial = 1 (Delta 7000)
|payloads =
|boosters =3, 4 or 9
|diff = 6000 Series
|boostername =[[Castor 4A]]
|boosterengines =1 [[solid rocket|Solid]]
|boosterthrust =478.3 [[newton (unit)|kN]]
|alt-boosterthrust =107,530 [[pound force|lb<sub>f</sub>]]
|boosterSI =266 sec
|boostertime =56 seconds
|boosterfuel =[[solid rocket|Solid]]
|alt-boosters =3, 4 or 9
|alt-diff = 7000 Series
|alt-boostername =[[Graphite-Epoxy Motor|GEM 40]]
|alt-boosterengines =1 [[solid rocket|Solid]]
|alt-boostersthrust =492.9 [[newton (unit)|kN]]
|alt-alt-boosterthrust =110,800 [[pound force|lb<sub>f</sub>]]
|alt-boosterSI =274 sec
|alt-boostertime =64 seconds
|alt-boosterfuel =[[solid rocket|solid]]
|alt2-boosters =9
|alt2-diff = 7000 Heavy
|alt2-boostername =[[Graphite-Epoxy Motor|GEM 46]]
|alt2-boosterengines =1 [[solid rocket|solid]]
|alt2-boostersthrust =628.3 [[newton (unit)|kN]]
|alt2-alt-boosterthrust =141,250 [[pound force|lb<sub>f</sub>]]
|alt2-boosterSI =278 sec
|alt2-boostertime =75 seconds
|alt2-boosterfuel =[[solid rocket|solid]]
|stage1name =Thor/Delta XLT-C
|stage1engines =1 [[RS-27A]][http://www.boeing.com/defense-space/space/delta/delta2/delta2.htm]
|stage1thrust =1,054.2 [[newton (unit)|kN]]
|alt-stage1thrust =237,000 [[pound force|lb<sub>f</sub>]]
|stage1SI =302 sec
|stage1time =265 seconds
|stage1fuel =[[Kerosene]]/[[LOX]]
|stage2name =Delta K
|stage2engines =1 [[AJ-10]]
|stage2thrust =43.6 kN
|alt-stage2thrust =9,800 lb<sub>f</sub>
|stage2SI =319 sec
|stage2time =431 seconds
|stage2fuel =[[Dinitrogen tetroxide]]/[[Aerozine]]
|stage3name =[[Payload Assist Module|PAM-D]] (optional)
|stage3engines =1 [[Star 48B]]
|stage3thrust =66.0 kN
|alt-stage3thrust =14,837 lb<sub>f</sub>
|stage3SI =286 sec
|stage3time =87 seconds
|stage3fuel =Solid
}}
'''Delta II''' is a space [[launch system]] originally designed and built by [[McDonnell Douglas]]. Delta II is part of the [[Delta rocket]] family and has been in service since [[1989]]. Delta II vehicles include the retired Delta 6000, the active Delta 7000, and two 7000 variants (light and heavy). Delta II rockets were later built by [[Boeing Integrated Defense Systems|Boeing Integrated Defense Systems]] until Delta rocket production became the responsibility of [[United Launch Alliance]] (ULA) on [[December 1]], [[2006]].<ref>[http://www.comspacewatch.com/news/viewpr.html?pid=21394 United Launch Alliance Transaction completed]</ref><ref>[http://www.boeing.com/defense-space/space/bls/deltaHistory.html Delta rocket history], Boeing. Accessed [[14 June]] [[2008]].</ref> ULA now markets Delta II to U.S. government customers, and Boeing Launch Services (BLS) markets Delta II to commercial companies.<ref name=newpd>{{cite web |url=http://www.ulalaunch.com/news_deltaIIProgramDirector.html |title=United Launch Alliance Restructures Delta II Program for Long Term Viability |publisher=ULA |date=2008-01-29}}</ref>
== History ==
All United States expendable launch vehicles were to be phased out for the [[Space Shuttle]], but in 1986 the [[Space Shuttle Challenger disaster|''Challenger'' accident]] restarted Delta development. The Delta II, specifically, was designed to accommodate the [[GPS]] Block II series of satellites. Delta IIs have successfully launched 125 projects (through August [[2007]]), including several [[NASA]] missions to [[Mars (planet)|Mars]]:
* [[Mars Global Surveyor]] in [[1996]]
* [[Mars Pathfinder]] in 1996
* [[Mars Climate Orbiter]] in [[1998]]
* [[Mars Polar Lander]] in [[1999]]
* [[Mars Odyssey]] in [[2001]]
* [[Mars Exploration Rover Mission|Mars Exploration Rovers]] ([[MER-A]], ''Spirit'' and [[MER-B]], ''Opportunity'') in [[2003]]
* [[Mars Phoenix]] lander in 2007
Delta II manufacturing, assembly and integration [[As of 2008 |currently]] take place in [[Decatur, Alabama]], [[Harlingen, Texas]], [[San Diego, California]], and [[Denver, Colorado]].<ref name=newpd />
==Vehicle description==
Deltas are [[expendable launch vehicle]]s (ELVs), which means they are used only once. Each launch vehicle consists of:
*Stage I: [[Kerosene]] and [[liquid oxygen]] tanks that feed the Rocketdyne [[RS-27A (rocket engine)|RS-27]] main engine for the ascent.
*[[Solid rocket booster]] motors: Used to increase thrust during the initial two minutes of flight. The medium-capacity Delta II has nine motors total (six fire on the ground, three in flight); the other models use only three or four.
*Stage II: Fuel and oxidizer tanks feeding a restartable, [[hypergolic]] [[Aerojet]] AJ10-118K engine that fires one or more times to insert the vehicle-spacecraft stack into [[low Earth orbit]]. This stage also contains the vehicle's "brains", a combined [[inertial platform]] and [[guidance system]] that controls all flight events.
*Stage III: Optional ATK-Thiokol solid rocket motor (some Delta II vehicles are two-stage only, and generally used for Earth-orbit missions) provides the majority of the velocity change needed to leave Earth orbit and inject the spacecraft on a trajectory to Mars or other target beyond Earth orbit. It is connected to the spacecraft until it is done firing, and then separates. This stage is [[Spin-stabilized satellite|spin-stabilized]] and has no active guidance control; it depends on the second stage for proper orientation prior to Stage II/III separation. It also includes a [[yo-yo de-spin]] mechanism to slow the spin before spacecraft release, as many spacecraft cannot handle the high spin rates needed for stability of this stage.
*Payload fairing: Thin metal or composite payload fairing (aka "nose cone") to protect the spacecraft during the ascent through Earth's atmosphere.
; Naming system
The Delta II family is more technically named by a four-digit system:<ref>{{cite web |url= http://kevinforsyth.net/delta/vehicle.htm |title= Vehicle Description and Designations| last = Forsyth | first = Kevin S. |accessdate= 2008-03-15|date=2007-08-10 |work= History of the Delta Launch Vehicle}}</ref>
*The '''first digit''' is either 6 or 7, denoting the 6000- or 7000-series Deltas. The 6000-series, last flown in 1992, had an Extra Extended Long Tank first stage with RS-27 main engine, plus [[Castor (rocket stage)|Castor]] IVA solid rocket boosters. The current model 7000-series have an [[RS-27A (rocket engine)|RS-27A]] engine, with a longer nozzle for higher expansion ratio and better high-altitude performance, and GEM ([[Graphite-Epoxy Motor]]) boosters. GEMs are larger, and have a composite casing to reduce mass versus the steel-case Castors. In addition, two LR101-NA-11 vernier engines provide guidance for the first stage.
*The '''second digit''' indicates the number of boosters, usually 9. In such cases, six are lit at liftoff and three are lit one minute into flight. On vehicles with 3 or 4 boosters, all are ignited at liftoff.
*The '''third digit''' is 2, denoting a second stage with an Aerojet AJ10 engine. This engine is restartable, for complex missions. Only Deltas prior to the 6000-series used a different engine, the TR-201.
*The '''last digit''' denotes the third stage. 0 denotes no third stage, 5 indicates a [[Payload Assist Module]] (PAM) stage with Star 48B solid motor, 6 indicates a Star 37FM motor.
For example, a Delta 7925 has the later first stage, nine GEM boosters, and a PAM third stage. A Delta 7320 is a two-stage vehicle with three boosters.
*A Delta II-Heavy has the larger GEM-46 boosters, originally designed for the [[Delta III rocket|Delta III]]. These are designated 79''xx''H.
Three payload fairings are available. The original aluminum fairing, seen above, is 9.5 feet in diameter. A 10-foot fairing is made of composite, and can be distinguished by its tapering front and rear. A lengthened 10-foot fairing is used for the largest payloads.
[[Image:Delta2 comparison 400.jpg|thumb|right|Comparison of standard vs. heavy Delta II]]
== Launch description ==
; Launch vehicle build-up
A Delta II launch vehicle is assembled vertically on the launch pad. Assembly starts by hoisting the first stage into position. The solid rocket boosters are then hoisted into position and mated with the first stage. Launch vehicle build-up then continues with the second stage being hoisted atop the first stage.<!-- Is there a better source for this info? --><ref>
{{cite web | url = http://www.nasa.gov/centers/kennedy/launchingrockets/status/2007/elvstatus-20070606.html | title = Expendable Launch Vehicle Status Report | date = June 6, 2007 | publisher = NASA}}</ref>
; Fueling
It takes approximately 20 minutes to load the first stage with {{convert|10000|USgal|L|-2}} of fuel.<ref>
{{cite web | url = http://www.nasa.gov/mission_pages/swift/launch/pad.html | title = Swift Launch Pad Activities | date = [[2004-11-18]]}}</ref>
== Delta II launches ==
{{see also | List of Delta II launches}}
The Delta II system has been used for 135 launches. On [[September 18]], [[2007]], Delta II completed its 75th consecutive successful launch.<ref>{{cite web | url = http://media.digitalglobe.com/index.php?s=press_release_popup&item=135 | title = DigitalGlobe Successfully Launches Worldview-1 | publisher = DigitalGlobe}}</ref> This is a record for modern launch vehicles.<ref>{{cite web | url = http://www.spaceflightnow.com/delta/d326/status.html | title = Mission Status Center (Delta 326) | publisher = Spaceflight Now | last = Ray | first = Justin | accessdate = 2007-09-26}}</ref> It is the second most reliable launch vehicle currently in service, behind the [[Tsyklon 2]].<ref>[http://www.geocities.com/launchreport/reliability2007.txt Space Launch Report - Active Launch Vehicle Reliability Statistics]</ref> Eight launches took place in [[2007]].
However, the Delta II system does not have a perfect success record. One mission, the launch of [[Koreasat-1]], was a partial failure in which the satellite payload was able to compensate when the launch system placed the vehicle in an incorrect orbit.<ref>
{{cite web | url = http://www.skyrocket.de/space/doc_sdat/koreasat-1.htm | title = Koreasat 1, 2 (Mugungwha 1, 2) / Europe*Star B | last = Krebs | first = Gunter Dirk}}</ref>
Another failure, this time complete, occurred on [[January 17]], [[1997]], when a Delta II 7925 carrying the first [[Global positioning system|GPS]] Block IIR satellite exploded only 13 seconds after liftoff, raining flaming debris all over Launch Complex 17 at Cape Canaveral Air Force Station. No one was injured, and the launchpad itself was not seriously damaged, though several cars were destroyed and a few buildings were damaged.<ref>[http://www.cnn.com/TECH/9701/17/rocket.explosion/index.html CNN - Unmanned rocket explodes after liftoff - Jan. 17, 1997<!-- Bot generated title -->]</ref>
=== Notable payloads ===
<div style="-moz-column-width:15em; column-width:15em;">
* [[2001 Mars Odyssey]]
* [[CONTOUR]]
* [[Dawn (spacecraft)|Dawn]]
* [[Deep Impact (spacecraft)|Deep Impact]]
* [[Deep Space 1]]
* [[Gamma-ray_Large_Area_Space_Telescope|GLAST]]
* [[Mars Climate Orbiter]]
* [[Mars Exploration Rover]]s
* [[Mars Global Surveyor]]
* [[Mars Pathfinder]]
* [[Mars Phoenix]] lander
* [[Mars Polar Lander]]
* [[MESSENGER]]
* [[NEAR Shoemaker|NEAR]]
* [[Polar (satellite)]]
* [[ROSAT]]
* [[Spitzer Space Telescope|SIRTF]]
* [[STEREO]]
* [[Swift Gamma-Ray Burst Mission|Swift]]
* [[THEMIS]]
* [[USA 193]] (NROL-21)
* [[WIND]]
</div>
Between May 1997 and November 1998 Delta II vehicles placed 55 [[Iridium (satellite)|Iridium]] satellites into orbit.<ref>
{{cite web | url = http://www.boeing.com/news/releases/2002/q1/nr_020205s.html | title = Boeing Delta II to Launch New Additions to Iridium Constellation | publisher = Boeing}}</ref>
== Retirement of system ==
An article published by the ''[[Wall Street Journal]]'' speculates about the fate of the Delta II launch system after U.S. Air Force discontinues its use of the Delta II.<ref>
{{cite web | title = Delta II's Fate Worries Nonmilitary Users | url = http://online.wsj.com/article/SB118039764439516631.html?mod=googlenews_wsj | publisher = WSJ}}</ref> Thomas Young, who was director of [[Goddard Space Flight Center]] from 1980 to 1982, is quoted as saying, "It's definitely an item people are quite worried about."
The final payload currently scheduled for Delta II is a NASA moon mission in [[2011]].<ref>{{cite news |first= |last= |authorlink= |author= |coauthors= |title=Launch team packs rockets' timetable |url=http://www.floridatoday.com/apps/pbcs.dll/article?AID=/20080525/BUSINESS/805250328/1007/news02 |format= |work= |publisher=Florida Today |location= |id= |pages= |page= |date=[[2008-05-25]] |accessdate=2008-06-09 |language= |quote=United Launch Alliance piled up a half-dozen new payloads for Atlas and Delta rockets during the first half of the year, including a NASA moon mission that will extend Delta 2 launch operations. |archiveurl= |archivedate= }}</ref> ULA has indicated it has "around half a dozen" unsold Delta II rockets on hand.<ref name=until2015>{{cite web |url=http://www.space.com/businesstechnology/080630-busmon-delta-2.html |title=Delta 2 Rockets to Remain Competitive Until 2015 |first=Brian |last=Berger |publisher=Space News |date=2008-06-30}}</ref> A spokesperson indicated ULA will change some aspects of the Delta II system once the current Medium Launch Vehicle 3 contract with the Air Force ends and requirements imposed by the contract are lifted. The Air Force contract required that Delta II be kept ready to launch within 40 days of call up, which led ULA to maintain two launch pads at Cape Canaveral. ULA indicated it would not continue to operate two launch pads.<ref name=until2015 />
== Future applications ==
The Aerojet-built second-stage engine has been chosen by [[NASA]] to be used as the main propulsion engine for the [[Orion spacecraft]] that will replace the [[Space Shuttle]] after 2010. The engine was chosen due to its restart capabilities along with a switch from the original liquid oxygen/liquid methane (LOX/LCH<sub>4</sub>) application to hypergolic fuel and oxidizer similar to that in use on the Shuttle's OMS and RCS systems.
== References ==
{{reflist |2}}
== External links ==
{{Commonscat-inline|Delta (Rocket)}}
* [http://www.boeing.com/defense-space/space/delta/delta2/delta2.htm Boeing Delta II Page]
* [http://www.skyrocket.de/space/doc_lau/delta.htm Delta I, II und III Site from Gunter Krebs]
* [http://kevinforsyth.net/delta/ History of the Delta Launch Vehicle]
* [http://www.cnn.com/TECH/9701/17/rocket.explosion/index.html Article about 1997 failed launch and self-destruction (with video)]
<br clear=all>
[[Image:Delta rocket evolution.png|thumb|left|370px|Delta rocket evolution (U.S. Govt.)]]
{{ELVs}}
[[Category:Space launch vehicles]]
[[Category:Boeing]]
[[bg:Делта II]]
[[de:Delta II]]
[[es:Delta II]]
[[fr:Delta II]]
[[it:Delta II]]
[[ka:დელტა-2]]
[[hu:Delta–2]]
[[nl:Delta II]]
[[pl:Delta II]]
[[pt:Foguete Delta II]]
[[sh:Delta II]]
[[fi:Delta II]]
[[vi:Delta II]]
[[uk:Delta-2]]
[[zh:德尔塔-2运载火箭]]