Talk:Delta IV

Talk

Corrected some incorrect data about the launch sites and spacecraft. -- Nick L.

I'm not sure if this can be used for anything, but there's a nice photo of the Delta IV's second-stage here: http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=24253 --NeuronExMachina 02:15, 19 Dec 2004 (UTC)

I read that Boeing and Mitsubishi were developing a more powerful upper stage engine called MB-60 for use on the Delta IV. However, I have not seen any updates for several years. Does anyone know if this is still being developed?--Todd Kloos 04:23, 24 Dec 2004 (UTC)

Capitalization of class names

The Boeing site (from the link on the main page) refers to each variant with a capitalized name (i.e. Medium or Heavy as opposed to medium or heavy) whenever they are reffered to. Because of this, and if no one objects, I'd like to go through and change all of the references to this format. I think it can be succesfully argued that these are all proper nouns as used, rather than simply adjectives. --Icelight 29 June 2005 15:25 (UTC)

Upcoming Delta IV launch

If nobody has a problem with it, I would like to add some info about the upcoming GOES-N launch on a Delta IV tomorrow. Nick L. 15:57, 28 July 2005 (UTC)

Launch delayed ;-) --Bricktop 22:15, 28 July 2005 (UTC)

The first launch of a valuable payload aboard the Delta IV Heavy is scheduled for fall 2005 -- does this article need an update? Ojw 20:44, 20 January 2006 (UTC)

The GOES-N flight is currently scheduled for Feburary 6, 2006. Might as well wait until the launch to do an update. Linky. Jbanes 21:51, 3 February 2006 (UTC)

• Those were taken care of by others today. I corrected the wording on DSP-23 and added NROL-25 & 26 based on launch manifest[1] (forgot to login). -Finlayson 03:43, 25 May 2006 (UTC)

This section of the article is out-of-date again. Ronstew 19:01, 10 October 2007 (UTC)

SLC-37B not site of Apollo 1 or 7

The page had stated that Delta IVs launched from the "same site" as the Apollo 1 fire and Apollo 7, however, those launches were from SLC-34, just next door to 37B. The Apollo_1 and Apollo_7 pages confirm this. I can also vouch from personal experience, having stood inside the launch ring on SLC-34 and seen a loaded booster from the parking lot at SLC-37. (sadly, that launch got scrubbed and I missed it. :()

Partial success

I'm new here so someone who knows better please fix the laugable "partial sucesess" thing re the dec 2004 launch. Eliminating POV, that means failure. Wiki is not a public relations firm is it. —The preceding unsigned comment was added by 65.188.193.14 (talk • contribs) .

I don't see where calling something a "partial success" is POV. Doing any activity is rarely black and white. Launching rockets is no different. Had the payload been lost that would be a failure. This was a demonstration launch. Most of the goals of the demonstration were met. There was a failure in terms of the early fuel out indication, but the test payload did make it into orbit. For me at least that fits as partial.

On one other note, please sign your comments on talk pages with four tildes (~~~~) to let others know who said what. Thanks. --StuffOfInterest 13:09, 20 January 2006 (UTC)

I would like to throw in a few cents. Partial success is used in numerous places in the industry to describe notable accidents that didn't cause a complete mission loss of the launch vehicle. You see it in the standard text International Reference Guide to Space Launch Systems, Iaskowitz, Hopkins, and Hopkins. You see it in other industry reference sites etc. If you don't like its use that's fine, but there's a difference between it being marketing fluff by Boeing and it being the standard way the industry talks about such accidents. Having the article consistent with industry practice is perfectly reasonable. Georgewilliamherbert 22:36, 20 January 2006 (UTC)

If the mission were carrying a real satellite, then yes, it would be a failure. However, in light of what the mission was - a TEST mission, it is a partial success. This is why the USAF decided to fly a test mission, to make sure everything works. Not only did this mission prove out many aspects of the Heavy variant, it accomplished what a test flight is meant to do - find problems so that they can be fixed before something important ends up in a low orbit. Nick L. 06:37, 21 January 2006 (UTC)

RS-68 details-move to own page?

I thought that this article had too much of a focus on the RS-68, so I removed some of the information from the article (i.e the channel-wall construction, etc...) and plan on moving it to the RS-68 article. Any opinions or objections? Nick L. 15:19, 21 July 2006 (UTC)

• Good move. The Delta article doesn't need every detail on the RS-68 engine. - Fnlayson 15:53, 21 July 2006 (UTC)

Standard article titles?

Randomly discovered that while this article is called Delta IV rocket, while Delta II rocket is a redirect to Delta II. Maybe something more standard? -b 19:33, 20 August 2006 (UTC)

• The titles probably should include rocket to be consistent. Delta rocket needs rocket in the name to prevent confusion with other things. -Fnlayson 20:46, 20 August 2006 (UTC)
• Oppose There are no valid grounds to disambiguate Delta II or Delta IV. GW_Simulations_{|User Page | Talk | Contribs | Chess | E-mail} 22:59, 21 August 2006 (UTC)

Requested move

The following discussion is an archived debate of the proposal. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the debate was Delta IV rocket → Delta IV – Unnecessary disambiguation GW_Simulations_{|User Page | Talk | Contribs | Chess | E-mail} 18:49, 21 August 2006 (UTC)

Survey

Add "* Support" or "* Oppose" followed by an optional one-sentence explanation, then sign your opinion with ~~~~

• Oppose. Delta rocket and Delta III rocket both contain "rocket" in the title as well - this article's title is consistent with that, if anything, Delta II should be changed. Nick L. 19:09, 21 August 2006 (UTC)

These contain "rocket" because there is a valid disambiguation - pages already exist at Delta and Delta III. In this case, Delta IV simply redirects here, so it is not a valid disambiguation. --GW_Simulations_{|User Page | Talk | Contribs | Chess | E-mail} 19:12, 21 August 2006 (UTC)

Ah, I see - I didn't understand the request properly. Strike my vote. Nick L. 19:35, 21 August 2006 (UTC)

After further consideration, I am unstriking my vote. Nick L. 00:55, 27 August 2006 (UTC)

• Oppose. The Delta article has rocket in the name to avoid disambiguity. The other Delta vehicle articles should be consistent with that. -Fnlayson 22:46, 21 August 2006 (UTC)

But there is nothing here to avoid ambiguity with. --GW_Simulations_{User Page | Talk} 11:30, 26 August 2006 (UTC)

• That's already been stated. The name change will make little difference with Redirects anyway. -Fnlayson 16:12, 26 August 2006 (UTC)

• Support. There is no disambiguation page named "Delta IV". Bigtop 16:57, 22 August 2006 (UTC)
• Support. -b 14:49, 23 August 2006 (UTC)
• Oppose. Better to keep it consistent with Delta III rocket, which can't change. Andrewa 02:55, 27 August 2006 (UTC)

Discussion

• Closing RM after a week.. doesn't look like consensus to move. Leaving here for now. -Goldom ‽‽‽ ⁂ 03:58, 27 August 2006 (UTC)

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

• I know it's too late to vote, but the reasons for not moving above are not very convincing. Disambiguation should be done with parenthetic remarks to make it clear what the name of the subject of the article is (the part that is not in parentheses). Making "rocket" part of the title implies that "rocket" is part of the name of the rocket. --Serge 23:34, 1 September 2006 (UTC)

Infoboxes

Looks like a fair amount of the infomation in the 2 infoboxes is common for both like 1st and 2nd stage engines. One infobox with extra lines for the different vehicle type would cover things. Anybody see a problem with this? -Fnlayson 17:09, 23 September 2006 (UTC)

Done. --GW_Simulations_{User Page | Talk} 19:10, 28 September 2006 (UTC)

Looks good, thanks. -Fnlayson 19:33, 28 September 2006 (UTC)

Splitting the Delta IV article

• The proposal is to split away the past & planned launches in to a seperate article to clear away large amounts of technicla data.--aceslead 20:52, 22 October 2006 (UTC)

Survey

Add "* Support" or "* Oppose" followed by an optional one-sentence explanation, then sign your opinion with ~~~~

• SUPPORT The article has gotten to long with technical facts about past and planed launches. That information should be split off into a seperate article with all that technical data of past, present and future launches.--aceslead 20:29, 22 October 2006 (UTC)
• Oppose A seperate launch page is not needed yet. The launch list and launch tables have redundant info. Cull info down or remove tables. -Fnlayson 08:08, 23 October 2006 (UTC)

Discussion

• Perhaps ALL the "Delta launches" for Delta II, Delta III, & Delta IV.--aceslead 20:29, 22 October 2006 (UTC)
• Funny you should mention it. I have been working (offline) on such an article for the last few days. I have finished the 0100, 1000 and 6000, and have most of the 2000 and 7000, along with some of the 3000. It should be online soon. Although I have no intention of changing the content of these articles when it is created, I suppose that it would be an option.--GW_Simulations_{User Page | Talk} 08:42, 23 October 2006 (UTC)

Delta IV Small?

I don't see why this is listed in the Infobox. It was proposed at one stage in the development, but that's it. If someone wants to mention this in the article that's fine btu it shouldn't be in the infobox. -Fnlayson 15:17, 4 November 2006 (UTC)

• The removal of the DIV Small is already explained at the bottom of the variant section. Overlap with the Delta II is one reason, I beleive. -Fnlayson 00:27, 5 November 2006 (UTC)

To restart an old debate...

A while ago we debated moving Delta IV rocket to Delta IV. This was rejected for consistency with Delta III rocket, which is so named to disambiguate from Delta III class submarine. Delta III class submarine is now proposed to be merged into Delta class submarine. If this goes ahead, then iw would be possible to move both rocket articles (Delta IV rocket -> Delta IV and Delta III rocket -> Delta III). This addresses the objections raised before. --GW_Simulations_{User Page | Talk} 17:18, 4 November 2006 (UTC)

• Wasn't this already coverd by these proposals efforts? Wikipedia talk:Naming conventions (rockets) Wikipedia:WikiProject Launch vehicles#Naming conventions -Fnlayson 00:37, 5 November 2006 (UTC)
  • WP:ICBM fell through due to lack of interest, and the WP:LV proposal only covers what to do IF disambiguation is required, not whether it should be. For the record, I have merged the submarine articles that I mentioned above. --GW_Simulations_{User Page | Talk} 14:03, 12 November 2006 (UTC)

Launch Cost

The article says Delta IV launches are priced between $140-170 million. However this appears to only cover the cost of the Delta IV Medium's; astronautix.com states that the price of a Delta IV Heavy launch was "..revised by the USAF in November 2004 to $ 254 million." Perhaps a better breakdown of cost would be appropriate as follows (2004 dollars from astronautix.com, probably higher in 2006 accounting for inflation):

Medium $140 million

Medium+(4.2) $140 million

Medium+(5.2) $150 million

Medium+(5.4) $160 million

Heavy $254 million.

Thoughts? Subzero788 | talk 09:10, 5 November 2006 (UTC)

• Seems reasonable. Replace the periods with comma like (4,2) etc. though. The cost for the Heavy and other types that haven't launched (M+5,2 & M+5,4) will change (generally down) after a few launches. But that a topic for the future. -Fnlayson 16:40, 14 November 2006 (UTC)

Renaming to disambiguate (again)

There are or were seven "Delta IV" (Project 667BDRM, Delfin) submarines. I understand it has been discussed a zillion times, but would anyone strenuosly object if I rename this article to Delta IV (rocket) or Delta IV (launch system)? Can't we then easily pipe-trick the times we want articles to read, Delta IV? Sdsds 08:15, 16 April 2007 (UTC)

I have made these into redirects. You can now user the pipe trick without having to rename the article. -- Petri Krohn 13:05, 16 April 2007 (UTC)

Aerial Photo

The picture of "A unique aerial view of NROL-22 launch from SLC-6" Is obviously a picture of models as evidenced by the wooden toy trucks in the lower right corner of said photo.

Recommend that its caption be changed or the photo removed. ~~ChrisCTurner 02:28, 31 May 2008 (UTC)

Garbage. That's not models. It was NROL-22 launch from Vandenberg. Click on the image link and find this Air Force photos page. -Fnlayson (talk) 02:42, 31 May 2008 (UTC)

Thanks for the link. Just thought it looked like models and the object in the lower right corner still looks a lot like a wooden toy truck but I'll concede the point. —Preceding unsigned comment added by Chriscturner (talk • contribs) 04:14, 6 June 2008 (UTC)

Q on Throttling

The article says "Typically, the RS-68 runs at 102% rated thrust for the first few minutes of flight, and then throttles down to 58% rated thrust before main engine cutoff. On the Heavy variant, the core CBC's engine throttles down to 58% rated thrust around 50 seconds after liftoff, while the strap-on CBCs remain at 102%. This allows the core CBC to conserve propellant and burn longer." I assume under either scenario (with or without strap-ons), there is some advantage to throttling back, perhaps having to do with the fact that as you burn fuel and oxidizer, the vehicle masses less and less, and that throttling back maintains some kind of ideal thrust-to-mass ratio (although I don't understand why you wouldn't gradually throttle back as fuel burns, instead of dropping in one step from 102% to 58%). A side effect of that (mentioned in the quote) would be burning longer, although again it's not immediately obvious to me why lower thrust for a longer time is better than higher thrust for a shorter time (it's not the gradually lower air drag, is it?). Is there a discussion of this somewhere in wikipedia? And if so, could this para link to it? Mcswell (talk) 19:02, 28 June 2009 (UTC)

On the Heavy DIV, the 3 CBCs hold the same amount of fuel, so the center one is trottled back so it can burn after the strap-on CBCs are spent and jettisoned. -Fnlayson (talk) 20:07, 28 June 2009 (UTC)

I believe that the thrust is scaled back to limit the maximum acceleration (proportional to thrust/mass) that the payload or upper stage needs to endure, thereby allowing the upper stages to have reduced structural weight. I also gather that the RS-68 engine is only capable of either 102% or 58% thrust levels. That is, it is not continuously variable. As for the reason why it is not continuously variable, that I don't know. Increased development costs, perhaps? --71.214.211.224 (talk) 17:41, 10 October 2010 (UTC)

as you say, many boosters, cut throttle to avoid Over-G'ing the upper stage or payload.--71.178.199.89 (talk) 17:05, 13 April 2011 (UTC)

updated data, launch capacities

hello the launch capacities mentioned in this article are old and wrong and can be cleaned up from this new official 2009 source: http://www.ulalaunch.com/docs/product_sheet/DeltaIVProductCardFinal.pdf —Preceding unsigned comment added by 76.11.124.147 (talk) 14:37, 24 July 2009 (UTC)

Ares V info obsolete

The paragraph about using the RS-68 engine in the Ares V rocket (in the Future variants section) seems to be obsolete after the termination of this program. However, my knowledge is too limited to fix this properly. Sandeman684 (talk) 10:20, 13 March 2011 (UTC)

True, but the RS-68 was considered for use on the Ares V. I believe the RS-68 and Shuttle's SSME were both considered for that. I adjusted the wording to clarify this and use past tense. -Fnlayson (talk) 16:24, 13 March 2011 (UTC)

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)

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)