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Delta IV>Delta

• Long March 5
• Falcon Heavy
• Proton-M

{edih}| status = Retired| sites = {hide}unbulleted list List of USA satellites>USA-181)List of NRO launches#Launch history>NROL-70)

• EFT-1
• NRO classified payloads
  • Kennen
  • Orion
• Parker Solar Probe

{edih}| stagedata = }}The Delta IV Heavy (Delta 9250H) was an expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It was the world's third highest-capacity launch vehicle in operation at the time of its retirement in 2024, behind NASA's Space Launch System and SpaceX's Falcon Heavy and closely followed by CASC's Long March 5.WEB, Mission Status Center,weblink Spaceflight Now, 26 July 2014, The ULA Delta 4-Heavy is currently the world's largest rocket, providing the nation with reliable, proven, heavy lift capability for our country's national security payloads from both the east and west coasts., NEWS, Falcon Heavy, SpaceX's Big New Rocket, Succeeds in Its First Test Launch,weblink The New York Times, 6 February 2018, 6 February 2018, The Falcon Heavy is capable of lifting 140,000 pounds to low Earth orbit, more than any other rocket today., Chang, Kenneth, It was manufactured by United Launch Alliance (ULA) and was first launched in 2004.PRESS RELEASE, Boeing Delta IV Heavy Achieves Major Test Objectives in First Flight, December 21, 2004, Boeing,weblinkweblink" title="web.archive.org/web/20120419170931weblink">weblink 19 April 2012, 22 March 2012, ULA retired the Delta IV Heavy in 2024. Future ULA launches will use the new Vulcan Centaur rocket.WEB, Erwin, Sandra, ULA to launch Delta 4 Heavy for its 12th mission, four more to go before rocket is retired,weblink SpaceNews, 24 August 2020, 29 August 2020, WEB,weblink Delta IV Heavy - NROL-70, 9 February 2024, 10 February 2024, Next Spaceflight, Delta IV's final flight was in 9 April 2024.The Delta IV Heavy first stage consisted of a central Common Booster Core (CBC), with two additional CBCs as liquid rocket boosters instead of the GEM-60 solid rocket motors used by the Delta IV Medium+ versions. At lift-off, all three rocket engines would operate at full thrust, and 44 seconds later the central engine would throttle down to 55% to conserve fuel until the other two engines separate. The latter engines burn out at 242 seconds after launch and are separated as the central engine throttles back up to full thrust. The central engine burns out 86 seconds later, and the second stage completed the ascent to orbit.WEB,weblink Delta IV Payload Planner's Guide, June 2013, United Launch Alliance,weblink" title="web.archive.org/web/20140710005717weblink">weblink July 10, 2014, July 26, 2014, dead, The launch vehicle used three RS-68 engines, one in the central core and one in each booster.WEB,weblink Delta 4-Heavy likely heading for geosynchronous orbit with top secret payload, Spaceflight Now, 26 August 2020, 27 August 2020, On the last seconds of countdown, the liquid hydrogen fuel would flow through the engines and upwards along the booster body, and after the ignition that hydrogen inflamed, creating the characteristic fireball and charred look of the booster.WEB, Berger, Eric, Eric Berger (journalist), 2019-01-21, This massive rocket creates a fireball as it launches, and that's by design,weblink 2023-04-13, Ars Technica,

History

File:Delta IV Heavy on pad with Orion EFT-1 (KSC-2014-4686).jpg|thumb|392x392px|left|Delta IV Heavy for Exploration Flight Test-1Exploration Flight Test-1The Delta IV line of rockets were developed by Boeing. The program was later transferred to United Launch Alliance. The Delta IV Heavy was the most powerful member of the line, which also includes the smaller Delta IV Medium.NEWS, Howell, Elizabeth, 2018-04-20, Delta IV Heavy: Powerful Launch Vehicle,weblink 2018-07-21, Space.com, The Delta IV Heavy can lift {{cvt|28370|kg}} to low Earth orbit and {{cvt|13810|kg}} to geostationary transfer orbit (GTO). It was an all liquid-fueled launch vehicle, consisting of an upper stage, one main booster and two strap-on boosters.The first launch of the Delta IV Heavy on 21 December 2004 carried a boilerplate payload and was a partial failure. Cavitation in the liquid-oxygen propellant lines caused shutdown of both boosters eight seconds early, and the core engine nine seconds early; this resulted in a lower staging velocity for which the second stage was unable to compensate. The payload was left in a lower than intended orbit.WEB, Delta 4-Heavy investigation identifies rocket's problem,weblink Spaceflight Now, 16 March 2005, 26 July 2014, Its first operational payload was the DSP-23 satellite, successfully launched in 2007; it was then used to launch a further five visual and electronic reconnaissance satellites for the National Reconnaissance Office (NRO) through 2013. In December 2014, the Delta IV Heavy was used to launch an uncrewed test flight of the Orion spacecraft, designated Exploration Flight Test-1 (EFT-1). After several delays, the mission was successfully launched at 12:05 UTC on 5 December 2014.WEB,weblink Second Stage Ignites as First Stage Falls Away, 5 December 2014, {{PD-notice}}On 12 August 2018, the Delta IV Heavy with an additional Star 48BV third stage was used to launch the Parker Solar Probe into an elliptical heliocentric orbit.WEB, Delta IV Parker Solar Probe,weblink 2020-12-11, ulalaunch.com, In May 2023, the final Delta IV Heavy core and boosters finished construction, officially ending Delta IV production and making way for the Vulcan launch vehicle.WEB, ULA's Delta rocket assembly line falls silent,weblink Spaceflight Now, The final Delta IV heavy would launch on April 9, 2024.Delta IV's final flight was initially scheduled for March 29, 2024 for the National Reconnaissance Office;NEWS, Chang, Kenneth, A Fiery Finale for a Rocket That Brings the Heat - The Delta IV Heavy, a rocket that briefly bursts into flame just before it lifts off, is set to launch for the last time soon.,weblink 28 March 2024, The New York Times, live,weblink 28 March 2024, 29 March 2024, WEB, Angle, Richard, 2024-03-15, United Launch Alliance's Delta IV Heavy readies for final flight,weblink 2024-03-21, TESLARATI, en-US, its actual launch date was April 9, 2024 after a postponement.WEB, Pare, Sascha, 2024-03-28, Secretive Delta IV Heavy rocket launch postponed indefinitely,weblink 2024-03-30, livescience.com, WEB, Delta IV Heavy NROL-70,weblink 2024-04-08, www.ulalaunch.com, WEB, Robert Z. Pearlman, 2024-04-09, 'Heavy' history: ULA launches final Delta rocket after 64 years (video, photos),weblink 2024-04-11, Space.com, en,

Capabilities

Capacity of the Delta IV Heavy:

• Low Earth orbit (LEO), 200 km × 28.7°: {{cvt|28790|kg}}
• Low Earth orbit (ISS), 407 km × 51.6°: {{cvt|25980|kg}} WEB, Delta IV Data Sheet,weblinkweblink" title="archive.today/20121206044535weblink">weblink usurped, 6 December 2012, Space Launch Report, 26 July 2014,
• Geosynchronous transfer orbit (GTO): {{cvt|14220|kg}} WEB,weblinkweblink" title="web.archive.org/web/20131014123330weblink">weblink 4 June 2013, Delta IV Launch Services User's Guide – June 2013, United Launch Alliance, 14 October 2013, 31 October 2020, 2–10,5-3,
• Geosynchronous orbit (GEO): {{cvt|6750|kg}}
• Lunar transfer orbit (LTO): {{cvt|10000|kg}}
• Mars transfer orbit: {{cvt|8000|kg}} WEB,weblink The Heavy: Triple-sized Delta 4 rocket to debut, Ray, Justin, Spaceflight Now, 13 May 2014,weblink" title="web.archive.org/web/20041211171244weblink">weblink 11 December 2004, 7 December 2004,

The Delta IV Heavy's total mass at launch was approximately {{cvt|733000|kg}} and produce around {{cvt|952000|kg}} of thrust to power the rocket skyward at liftoff.WEB,weblink Live coverage: Launch of Delta 4-Heavy rocket set for early Saturday, Spaceflight Now, 29 August 2020, 29 August 2020,

Launch history

{{transcluded section|source=List of Delta IV Heavy launches}}{{#section-h:List of Delta IV Heavy launches|Launch History}}{{Notelist}}

Comparable vehicles

{{further|Heavy-lift launch vehicle}}{{div col|colwidth=35em}}Current:

• Long March 5 (geostationary transfer orbit)
• Long March 5B (low Earth orbit)
• Long March 7A (geostationary transfer orbit)
• Falcon Heavy
• Proton-M
• Vulcan Centaur
• Angara A5

In development:

• Ariane 6
• New Glenn

Retired or cancelled:

• Ariane 5 (retired)
• Atlas V Heavy (proposed, never developed)
• Saturn IB (retired)
• Titan III (retired)
• Titan IV (retired)

{{div col end}}

See also

• Comparison of orbital launch systems
• Comparison of orbital rocket engines
• National Launch System, (1991–1993) study

References

{{Reflist|30em}}

External links

• Delta IV Booster Integration Another Step Toward First Orion Flight

{{United Launch Alliance}}{{Thor and Delta rockets}}{{Psp}}{{Expendable launch systems}}{{US launch systems}}