Editing Delta IV (section)

=== Successors ===
The [[Vulcan Centaur]] is planned to replace the [[Atlas V]] and Delta IV rockets. Vulcan Centaur had been projected to enter service by 2023, using the [[BE-4]] [[methane]]-fueled rocket engine,<ref>{{Cite news |last=Mike Gruss |date=13 April 2015 |title=ULA's Next Rocket To Be Named Vulcan |url=http://spacenews.com/ulas-next-rocket-to-be-named-vulcan/ |publisher=Space News}}</ref><ref>{{Cite web |last=Roulette |first=Joey |date=10 October 2022 |title=United Launch Alliance's debut Vulcan mission slips to 2023 -CEO |url=https://www.reuters.com/lifestyle/science/united-launch-alliances-debut-vulcan-mission-slips-2023-ceo-2022-10-10/ |access-date=24 October 2022 |website=[[Reuters]]}}</ref> but the first Vulcan launched on 8 January 2024.<ref>{{Cite news |last=Belam |first=Martin |date=2024-01-08 |title=Nasa Peregrine 1 launch: Vulcan Centaur rocket carrying Nasa moon lander lifts off in Florida – live updates |url=https://www.theguardian.com/science/live/2024/jan/08/nasa-peregrine-1-launch-rocket-moon-latest-news-updates-live |access-date=2024-01-08 |work=the Guardian |language=en-GB |issn=0261-3077}}</ref> The Atlas V is expected to stay in service for a few years after Vulcan's inaugural launch, and the Delta IV Heavy was discontinued in April 2024.<ref>{{Cite news |last=Stephen Clark |date=19 August 2019 |title=ULA's second launch of the month scheduled for Thursday |url=https://spaceflightnow.com/2019/08/19/ulas-second-launch-of-the-month-scheduled-for-thursday/ |publisher=Spaceflight Now}}</ref>