Shipbucket

CobaltWolf wrote: ↑February 19th, 2019, 2:06 pm Those are amazing! Hard to believe how many variants of the Delta (and Atlas) there were! Surprising to think that the Titan sheet may well have the fewest number of variants on it.

erik_t wrote: ↑February 19th, 2019, 2:18 pm Oh man, I love the crazy Delta IV derivatives. For those unaware, the 7-CBC superheavy could rival Saturn V in LEO throw weight. I'm not familiar with this specific generation of next-gen Delta, but I wouldn't be surprised if it could surpass S-V.

(PDF from ULA on Delta IV derivatives)

• Delta F and Delta H are no-booster version of the Delta E and Delta G respectively
• Delta K (in the three, six, and nine booster options) is a Delta M, but with a new eight foot diameter hydrogen-oxygen second stage (some references call this HOSS)
• Delta Lite was a proposed low cost launcher for the Mars Environmental SURvey (MESUR) program. In the end, MESUR was reduced to just one launch (Mars Pathfinder), and the proposal died.
• Delta II 7930 was a proposal for what would eventually mature into the Delta III
• Double Barrel Deltas were proposals to get truly Atlas level payloads out of Delta hardware
• Delta IV Small was a part of the EELV program. It consists of a Delta IV Common Booster Core, with a Delta II upper stage for smaller payloads. The small option was dropped from both EELV proposals when the USAF determined that it would be more cost effective to fly Delta IIs, and EELV Mediums that to test and fly a new configuration
• Delta IV M+ (4, 4) is just an M+ (5, 4), but with the smaller 4m upper stage (shared with the Delta III and cryogenic Double Barrel Delta).
• Delta IV M ( 5, 0) is a Delta IV Medium, but with the 5 meter upper stage. It offers no real performance gain over the Delta IV Medium and only a slightly larger fairing. Due to the added mass of the larger second stage, lift-off thrust to weight on this rocket is anemic at best (under 1.2 with no payload, which is considered a practical minimum for a launch vehicle)
• Delta IV M+ ( 5, 6) and ( 5, 8) are growth options that were never selected to offer payloads between the ( 5, 4) and Heavy. Most of the payloads in this weight class ended up on Atlas Vs.
• 'ACES' or Advanced Common Evolved Stage (at the time it was proposed for Delta IV - later versions changed this to Advanced Cryogenic Evolved Stage following the decision to end Delta IV production) was seen as a way of improving Delta IV performance by developing a new, higher capacity, lower mass upper stage using technologies under consideration at both Lockheed and Boeing prior to the merger of the space launch divisions into ULA. ACES documents exist as far back as 2007/8, but is expected to fly in the 2022/3 time frame on the ULA Vulcan rocket.
• With the Delta IV Heavies, we see various configurations of additional solids and larger payload fairings, as well as five and seven core super heavy versions.
• The Next Generation Delta proposals were very much paper rockets that Boeing had sketched out to offer as options for US Heavy Lift to support the Vision for Space Exploration. Historically, the VSE led to the Exploration Systems Architecture Study, which proposed what became the Ares I and V both of which were canned in 2010 after significant development issues.

erik_t wrote: ↑March 5th, 2019, 1:20 pm I've always found the massive external booster bracing on the H-IIAs to be interesting. For whatever reason, no other organization has ever felt the need to add such crossmembers. Presumably (as in, I'm presuming), the central tank at that axial station was not designed to take heavy side loads, and the booster cluster needs to mechanically interface with the center stage almost exclusively at the base (note that the previous longer boosters interfaced at an inter-tank section).

Beautiful drawings, as we've come to expect.