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After the space shuttle\u2019s retirement, ULA had the world\u2019s most powerful rocket in the Delta IV Heavy. It makes for a beautiful launch, as can be seen in these images from June 2016.<\/p>\n
Credit:
The fireball phenomenon manifests because of design differences between the RS-68 and the Shuttle main engines and because the RS-68 propellant valve is open longer before the oxidizer starts flowing. Essentially, at engine startup, only liquid hydrogen is running through the engine because it is less chemically active than oxygen.<\/p>\n
This hydrogen flows out of the engine, and because hydrogen is very light compared to ambient air, it rises up the outside of the rocket. When the liquid oxygen flow begins, the excess hydrogen is ignited into a fireball. This occurs within the last five seconds of the countdown. This design trade was intentional, and the exterior of the rocket is configured to withstand the fireball.<\/p>\n
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It looked amazing every time.<\/p>\n
A glimpse of the future<\/h2>\n After the retirement of NASA\u2019s space shuttle in 2011, the Delta IV Heavy became the most powerful operational rocket in the world, with a lift capacity of nearly 29 metric tons to low-Earth orbit. Only a handful of government-developed vehicles, including NASA\u2019s Saturn V lunar rocket and Russia\u2019s Energia vehicle, had more lift capacity.<\/p>\n
There was a time, now about 20 years ago when the Delta IV Heavy was considered the primary launch vehicle for the Orion spacecraft NASA was developing. With a more powerful upper stage\u2014later to be known as the Advanced Cryogenic Evolved Stage (ACES)\u2014it could have played a role in human exploration beyond low-Earth orbit.<\/p>\n
However, in 2006, NASA Administrator Mike Griffin quashed such notions by commissioning the Exploration Systems Architecture Study, which led to the space agency eschewing commercial options and developing its own super heavy lift rocket. Eventually, this became known as the Space Launch System. NASA has spent more than $20 billion developing the SLS rocket, and its per-launch costs exceed $2 billion.<\/p>\n
For the last two decades, however, the existence of the Delta IV Heavy has offered another way. Namely, with multiple launches of commercial vehicles, known as distributed launch, NASA could foster a more sustainable exploration architecture with lower-cost rockets and in-space refueling. As late as 2019, some inside NASA were considering lunar missions using a combination of the Delta IV Heavy and SpaceX\u2019s Falcon Heavy rocket. The Delta IV booster seems hardly like a champion for commercial launch, but it honestly was. One could point to the Delta and Falcon heavy lift vehicles and say there was a better way.<\/p>\n
Of course, a different story unfolded. The Delta IV Heavy rocket is now finished. NASA, thanks to consistent congressional pressure, has stuck with the massive and costly Space Launch System rocket. It will likely fly a few more missions.<\/p>\n
Nevertheless, the future lies in distributed launch. SpaceX, with its Starship rocket, and Blue Origin, with its New Glenn vehicle, are both developing plans for multiple launches and propellant depots, with the aim of creating a sustainable plan for space exploration. To unlock this future they have taken the Delta IV Heavy one step further by incorporating reuse.<\/p>\n
It is dead, but the future it once promised is not.<\/p>\n","protected":false},"excerpt":{"rendered":"
United Launch Alliance\u2019s Delta IV Heavy rocket lifted off for the final time on Tuesday. United Launch Alliance United Launch Alliance\u2019s Delta IV Heavy rocket lifted off for the final time on Tuesday. United Launch Alliance The rocket will now go into retirement after 16 flights. United Launch Alliance The rocket will now go into […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1414,9713,21],"class_list":["post-45271","post","type-post","status-publish","format-standard","hentry","category-news","tag-delta-iv-heavy","tag-fireball","tag-space"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/45271"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=45271"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/45271\/revisions"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=45271"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=45271"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=45271"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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