Talk:Delta IV

History
Why is there nothing about the history of Delta IV? "The Delta IV entered the space launch market when global capacity was already much higher than demand" tells us nothing. Is it embarrassment that the only US space rocket is 60 years old? I suggest adding a brief history going back to the origins of Delta.Royalcourtier (talk) 02:51, 6 December 2014 (UTC) "Delta IV/Evolved Expendable Launch Vehicle Program On Oct. 16, 1998, the U.S. Air Force announced the procurement of 19 Boeing Delta IV launches for the Evolved Expendable Launch Vehicle (EELV) program valued at $1.38 billion. - "This initial launch services contract covers small, medium and heavy payload class launches from 2002 to 2006. It splits 28 missions in a dual-source procurement designed to encourage greater contractor investment and competition in the U.S. space launch industry, and to decrease the Air Force's overall development cost. - "The Air Force also entered into a $500 million agreement with Boeing, supplementing development of the Delta IV family of launch vehicles for meeting all Air Force EELV requirements. - "The Boeing Delta IV/Evolved Expendable Launch Vehicle Program (EELV) is a multi-year U.S. Air Force effort aimed at reducing space launch costs by more than 25 percent. To meet these requirements, Boeing is offering the Delta IV family of vehicles. The family includes five launch vehicles: Medium, Heavy, and three variants of the Medium vehicle, known as Medium-plus, which have been introduced to meet the needs of the commercial market. - "Program Timing "The EELV program development and procurement cycle began in 1995. During the first phase, four competitors completed a 15-month contract to validate low-cost concepts. In December 1996, two contractors were selected to participate in the second phase, known as the Pre-Engineering, Manufacturing and Development (Pre-EMD) phase, a firm, fixed-price 17-month contract worth $60 million for each company." - Rod57 (talk) 03:48, 5 January 2024 (UTC)
 * The U.S. Air Force announces the procurement of Boeing Delta IV launches covers it :

Primary Units of Measure
WP:UNITS says "In non-scientific articles relating to the United States, the primary units are US customary" applies since this is a US product. Some exceptions the Delta IV rocket that I can think of are payload mass and the 4 m and 5 m diameters. -Fnlayson (talk) 18:05, 18 March 2015 (UTC)


 * Why should payload be an exception? All other modern LVs Atlas V Antares Falcon 9 v1.1 Delta II Pegasus etc use SI primary units. If US customary is the primary unit, then the entire article and all the other ones should be changed to reflect that, including payload. Modern US spaceflight articles have been using SI without issue for a long time (this one has for over a decade), why crack the UNITS whip randomly? UNITS is a guideline, there are always exceptions, and common sense says these articles should remain consistent. - A ( Ch ) 18:57, 18 March 2015 (UTC)
 * WP:Other stuff exists. I am just stating what the MoS tells us to do. You can try invoking WP:IAR if you want. -Fnlayson (talk) 19:52, 18 March 2015 (UTC)
 * Then why is payload an exception? If MOS is to be rigorously applied, payload should be in US units. So MOS always has exceptions; modern US spaceflight articles have consistently used SI and this article should follow that convention.  A ( Ch ) 20:45, 18 March 2015 (UTC)


 * I agree; since the vehicle is currently active, SI is the appropriate primary unit, and there's no good reason to treat the payload differently (perhaps if the US manufacturer were stuck using English engineering units, with international payload customers, but that's not the case here.) Keeping one convention consistent in this article is certainly least confusing. JustinTime55 (talk) 19:43, 18 March 2015 (UTC)
 * I don't get why being active make SI primary? The DIV vehicles were designed primarily in US units as most US companies do. -Fnlayson (talk) 19:52, 18 March 2015 (UTC)
 * I certainly agree with your comment about US industry. I guess the two determining factors in whether SI primary makes sense, are (I have to confess ignorance about the specifics of the Delta IV):


 * How "private" is the rocket, i.e. does it fall under NASA's metric directive?
 * How dependent is it on the Delta legacy vehicle? JustinTime55 (talk) 20:07, 18 March 2015 (UTC)
 * I don't think it can be asserted that DIV was designed primarily in US units, and it's moot anyway - the issue is consistency with other modern US spaceflight articles.  A ( Ch ) 20:45, 18 March 2015 (UTC)
 * If consistency trumps everything, then I'm wasting my time here. -Fnlayson (talk) 20:51, 18 March 2015 (UTC)
 * Surely consistency is an important factor. If UNITS is enforced here, it should be equally applied to all US spaceflight articles, should it not?  A ( Ch ) 21:08, 18 March 2015 (UTC)
 * I think it should, but US spaceflight articles covers a lot of articles and not something I want to get into, hence I mentioned WP:Other stuff exists above. -Fnlayson (talk) 21:12, 18 March 2015 (UTC)
 * Therefore, since this article used SI primary for over a decade and was consistent with other US spaceflight articles, does applying UNITS here improve the article?  A ( Ch ) 21:21, 18 March 2015 (UTC)

Spacecraft articles overlap science and technology. I think that the consistency that matters is to inform the reader regardless of their nationality. Being that the metric International System is, well, international, I feel that the primary unit should be metric followed by a conversion to Imperial. As the WP article stands now, the primary for height is feet and the primary for diameter is meter (without conversion). Whatever you decide, do it consistently. Cheers, BatteryIncluded (talk) 21:16, 18 March 2015 (UTC)
 * The article is still inconsistent, with the primary unit for vehicle mass being lbm and the primary unit for payload mass being kg, also without conversion.  A ( Ch ) 08:18, 19 March 2015 (UTC)


 * My two cents: the primary units in the article are best if consistently in one system of measure.  I too take the approach on these things that for modern spaceflight-related vehicles and spacecraft, then SI units as primary and the more esoteric local units as secondary/parenthetical makes the most sense for the English Wikipedia's very large international readership.  So for me, since Delta IV is a modern launch vehicle, not one of the early history of tech type articles from 1960s, then SI (non-SI) is best.  N2e (talk) 12:33, 19 March 2015 (UTC)

Delta IV Medium
Is this configuration already retired? — Preceding unsigned comment added by 94.220.12.243 (talk) 08:38, 3 January 2017 (UTC)


 * ULA is retiring the the Delta IV Medium versions; the comparable Atlas V versions will be used instead since they cost less. Here's an article about that. -Fnlayson (talk) 15:31, 4 January 2017 (UTC)

Separate Delta IV and Delta Heavy Launches Page?
Most of the other rockets have separate launches pages, as that information is separate from the vehicles themselves. Should we move that information to a new page? UnknownM1 (talk) 06:18, 19 February 2018 (UTC)

I just noticed there is a weird kind of hybrid page of multiple different rockets, separated by decades, under the "Delta" wing. It is very confusing and sort of unhelpful. It seems that the whole page needs reform or rework. UnknownM1 (talk) 06:20, 19 February 2018 (UTC)


 * Note that the Delta Heavy IS still a Delta IV rocket variant. -Finlayson (talk) 13:42, 19 February 2018 (UTC)
 * No I am aware. I think it is a List of Thor and Delta Rocket Launches, but the article layout itself is confusing and there shouldn't be the same information on multiple pages. UnknownM1 (talk) 15:50, 19 February 2018 (UTC)
 * OK, I just wanted to clarify about keeping them together. Splitting up the launches by rocket model seems clearer than by decade as done with Thor and Delta launches now, imo. -Finlayson (talk) 16:16, 19 February 2018 (UTC)
 * Yes, launches should be grouped by major evolution, i.e. Delta "alpha", Delta "numeric", Delta II + III, Delta IV, Delta IV Heavy. As a rule of thumb, if a rocket version has a dedicated article, it probably deserves a dedicated list of launches. — JFG talk 17:38, 19 February 2018 (UTC)

Number of Launches (in Infobox)
The Delta IV rocket has launched 39 times, and it even says that later in the article. However, in the infobox it still says it's only launched 37 times. Can that please be updated? SnowballEffect (talk) 23:23, 12 May 2019 (UTC)


 * The Infobox has been updated now. You could have just updated them or started on it yourself. -Fnlayson (talk) 00:21, 13 May 2019 (UTC)