Talk:Delta II

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The Orbits data based on a translation of the Orbis data in the Delta_II aricle from the German speaking Wikipedia in the Version from June 10, 2006 15:45 CET. A List of the main Authors (History) in accordance with GNU FDL ist II&action=history here to be found.

What is the cost of the Delta boosters? I'd like to compute the cost per pound to low earth orbit for the various boosters.Wrwhiteal 15:09, 13 August 2006 (UTC)[reply]

Article title[edit]

I think this article should be Delta II rocket to be consistent with the other Delta vehicel articles. Comments? -Fnlayson 20:59, 20 August 2006 (UTC)[reply]

Oppose: Delta rocket and Delta III rocket have valid grounds to be disambiguated, seeing as there are already pages at Delta III and Delta rocket. Delta IV rocket has been listed at WP:RM to be moved to Delta IV as there are no grounds to disambiguate. Delta II also lacks grounds for disambiguation, so it should stay put. --GW_Simulations|User Page | Talk | Contribs | Chess | E-mail 19:20, 21 August 2006 (UTC)[reply]
For. Change title to be consistent. -Fnlayson 22:51, 21 August 2006 (UTC)[reply]

Video of the January 17 1997 Launch Failure[edit]

I know there is allready a small video in the CNN story that is linked in the table, but Google Video has a better quality video here. Someone can edit it in if you think it's worth linking.

Nozzles on boosters[edit]

The photo thumb at right

shows a Delta II 7925, used to launch Themis. Upon close inspection it's clear the nozzles on the boosters are not all identical. Some appear longer than others. Is it correct that the longer nozzles are on boosters ignited at higher altitude? Also, is it safe to assume these are GEM-40 boosters, since this flight was not termed "heavy"? Sdsds 03:46, 18 February 2007 (UTC)[reply]

Yes to both, I think. --GW_SimulationsUser Page | Talk 22:07, 26 February 2007 (UTC)[reply]

  • The nozzles angled out (longer) are fixed. Right, D2 uses GEM-40s except on the Heavy variant. -Fnlayson 03:52, 27 February 2007 (UTC)[reply]
    • All the nozzles are angled out, it's just more pronounced on the longer nozzles (which, yes, are the air-lit ones, for thrust efficiency). Fnlayson is correct that these are GEM-40s with fixed nozzles... I believe the GEM-46s used on D2-Heavy vehicles also have fixed nozzles, and that the Thrust Vector Control was only used with Delta III. Kevin Forsyth (talk) 02:28, 21 December 2007 (UTC)[reply]

Thing is Delta II rocket had an initial design where they thought they wouldn't need any boosters and thus their first stage isn't fully circular, a fuel pipe juts out from one side, preventing any symmetric booster configurations. Some time later, they were forced to increase payload and thus add boosters, so their boosters all lie on the same side(and no boosters on the other side) and are angled a bit to compensate for any rotatory torque trying to turn the rocket. This design makes it so that any booster farthest from the pipe(ie just opposite to it) is responsible for the most torque(a waste of energy) and is tilted and its thrust used for compensation and wasted. Thus weaker boosters are placed opposite to the pipe as they will result in least wastage, and the more powerful ones are placed at 90 degrees to the pipe, as they can now have symmetry for 2 each. These are tilted less(or not at all) as they produce less of the useless torque. Daiyusha (talk) 10:15, 29 November 2016 (UTC)[reply]

Wall Street Journal[edit]

Two problems with this:

  1. I am concerned that one news agency's speculation is non-notable
  2. The source of the citation is subscription-only.

I feel that this section should be removed. --GW_SimulationsUser Page | Talk 20:00, 9 July 2007 (UTC)[reply]

Full text is available at http://www.ngs.noaa.gov/CORS/Newsletter/053007.doc. Please read it and see if the concern raised by the WSJ author meets notability requirements for Wikipedia. (sdsds - talk) 20:09, 9 July 2007 (UTC)[reply]
I'm still not sure, but if we leave it in place, we should change the cite to your source. --GW_SimulationsUser Page | Talk 20:48, 10 July 2007 (UTC)[reply]

RS-27A, RS-27C[edit]

Sources differ regarding the name of the currently used RS-27 engine model. At astronautix.com, Mark Wade says it is the RS-27C. [1] But United Technologies / Pratt & Whitney (the manufacturer) say RS-27A. [2] With all due respect to astronautix,com, it seems like Wikipedia should rely on P&W for this. But currently the infobox uses RS-27C. Maybe we should gloss over this and just say, "RS-27"? (sdsds - talk) 15:01, 18 October 2007 (UTC)[reply]

  • I suspect the C designation is something that's used internally to signify some minor alterations to the engine, while the official marketing name remains RS-27A. I agree with you, preferring the P&W designation of RS-27A since that's what the manufacturer calls it. However, it's important to retain a letter (whether you choose A or C) to separate the current engine from the RS-27, since the change (12:1 expansion ratio on the nozzle, up from 8:1 on the RS-27) is very significant to performance. Kevin Forsyth 15:20, 18 October 2007 (UTC)[reply]

Arianespace and Dual Payload Attach Fitting[edit]

How does Arianespace get away with claiming, "Ariane 5 is the only commercial launcher in service today capable of simultaneously launching two payloads?"[3] Is the Delta II "Dual Payload Attach Fitting" no longer offered? (sdsds - talk) 16:58, 15 November 2007 (UTC)[reply]

Perhaps Arianespace doesn't consider Delta II to be a "commercial" launcher. Perhaps they don't consider the Proton rocket when it launches three GLONASS satellites at once to be a "commercial" launcher either. (sdsds - talk) 22:48, 20 December 2007 (UTC)[reply]
I bet you're right, given how few commercial launches Delta II and Proton fly these days (today's being a rare exception). Or maybe it's just marketing as usual -- claim whatever you want, as long as nobody calls you on it. Kevin Forsyth (talk) 02:28, 21 December 2007 (UTC)[reply]

For stage 1, kerosene or rp-1[edit]

In describing the first stage fuel, the article currently refers it as, and links to, kerosene. While this is correct, it is not as specific as RP-1. A NASA reference page dated 1991 says, "RP-1 is a fuel in the first-stage boosters of the Delta and Atlas-Centaur rockets." And of course the content of the RP-1 article is much more specific to a rocketry application like Delta II. Are there any advantages to retaining the kerosene terminology or linking? (sdsds - talk) 22:46, 20 December 2007 (UTC)[reply]

I would say that RP-1 should be used. Most other rocket articles use it. --GW_SimulationsUser Page | Talk 00:47, 21 December 2007 (UTC)[reply]
I concur, just because RP-1 is highly refined kerosene, doesn't make it the same thing. Kevin Forsyth (talk) 02:28, 21 December 2007 (UTC)[reply]

Number of flights[edit]

Justin Ray, writing at spaceflightnow.com, asserts that with GPS IIR-18 the Delta II system has been used for 134 missions (with 132 successes). Using the record of all Delta flights provided by Boeing, I have created at User:Sdsds/Sandbox/Delta II missions a numbered wikitable of all Delta II missions. Sure enough, with GPS IIR-18, it makes 134. Is there any objection to changing the article to reflect that count? (sdsds - talk) 08:09, 21 December 2007 (UTC)[reply]

I've checked, and the problem seems to be that the figures weren't updated for GPS-IIR-17 and Dawn. There was also a mathematical error in adding the total number of launches. I have corrected these, and the figures now match,. --GW_SimulationsUser Page | Talk 12:03, 21 December 2007 (UTC)[reply]

Boeing Launch Services[edit]

DigitalGlobe believes its WorldView-2 satellite will be launched by Delta II. In a press release dated April 16, 2008, DigitalGlobe included a quotation attributed to "Boeing Launch Services President Ken Heinly." Heinly said, “Boeing Launch Services is pleased to be working with DigitalGlobe in launching the WorldView-2 satellite [...] The continued reliability of our Delta II rockets will ensure another successful launch for both Boeing and DigitalGlobe.” I thus challenge the assertion, which has been reintroduced in this article multiple times, that: "Delta programs became the responsibility of United Launch Alliance on December 1, 2006." Is there support for this language beyond the cited source claiming future *government* payloads on Delta II are the responsibility of ULA? (sdsds - talk) 05:13, 14 June 2008 (UTC)[reply]

ULA is a joint venture (not a seperate company) and as such both Boeing and Lockheed Martin are still connected and involved. Boeing and Lockheed Martin work on satalities as well. The last 2 paragraphs here Delta history should clarify. -Fnlayson (talk) 12:18, 14 June 2008 (UTC)[reply]

Most reliable LV?[edit]

In this section: Delta_II#Delta_II_launches, the article states that the Delta II is the second most reliable launch vehicle currently in service behind the Tsyklon-2. Since that LV has been retired can anyone find a new ref and re-work that statement? -MBK004 20:27, 6 October 2008 (UTC)[reply]

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Successor[edit]

Which rocket will be used in future to launch payloads, which were launched by Delta II before retirement? — Preceding unsigned comment added by 94.220.11.148 (talk) 07:38, 5 May 2017 (UTC)[reply]

Good question - Was the 2008 statement on remaining inventory connected with an announcement of the retirement of the Delta II - and was it prompted by the formation of ULA so that Atlas V could take over the Delta II missions ? Was Delta II more expensive than Atlas V ? - Rod57 (talk) 18:04, 16 September 2018 (UTC)[reply]

Total number of launches: 155 or 156?[edit]

The article mentions, "The Delta II family launched 155 times" but the Infobox says 156 launches. Which value is correct? Sxg169 (talk) 16:19, 21 September 2018 (UTC)[reply]

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