Talk:McDonnell Douglas DC-X

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Old stuff[edit]

Should it be incorporated into this article? As well, It'd be good to get a picture of the DC-X up there. I'd like to have a picture that reflects the vertical landing capability of the Clipper (IMHO, it's the most impressive thing about the craft), but I couldn't find any pics on the net that were clearly public domain that looked good. BTW, I thought I read somewhere that all NASA or US gov pics or something were all copyright free (or unrestricted license or something), but I couldn't find it again. Is it true? What are the specifics?] lommer 20:01, 9 Apr 2004 (UTC)

[Actually, the ship did not explode. NASA at Marshal had previously "tested" the tanks although there was no need for them to do so, and cracked one in their usual thorough manner. When the ship fell over because NASA people hadn't connected the hydraulic line to one of the landing gear, the cracked tank leaked, and the ship burned. There was never an explosion and good fire prevention action might have saved it since the impact damage was miniscule. Jerry Pournelle. [DC/X was conceived in my living room and sold to National Space Council Chairman Dan Quayle by General Graham, Max Hunter, and me.]]

The above was posted by ip on Oct. 14, '04. I moved it here and changed the article -Lommer 02:26, 15 Oct 2004 (UTC)

Dr. Jerry Pournelle has a web site at, and his email address is On his web site, he commented about Wikipedia, and I wrote to him about how cool Wikipedia is, and sent him the URL for the DC-X page. I chose that page because I know he has a particular interest in it, as he had a hand in its creation. He wrote back to me, complaining that what was on the page wasn't quite right, and I replied to him that since it's a Wiki he could just fix it. He wrote back to me saying he had done so. Thus, I am confident that he did in fact write that text. I agree he didn't do a good job of fitting it into the article.

I have edited the article and incorporated some material from his comments and some more from his web site. I also added a couple of links to his site. I have tried to do a good job.

If you have any questions for him, you could send him an email, but it says on his web site right now that he is sick, so if it isn't urgent please give him a few days to get well. You may email me if you like: -- steveha 07:50, 18 Oct 2004 (UTC)

Cool, always good to see new people on wikipedia and someone as knowledgeably as pournelle will be an awesome contributer. -Lommer 15:49, 18 Oct 2004 (UTC)
The Clipper Graham Mishap Investigation Report from Nasa (final report) at (section 6.1, page 11) mentions three explosions within 125 seconds from impact, where "the third and final explosion rocked the accident scene when the hydrogen tank exploded scattering the composite material from the aeroshell and tank over the mishap scene". On the other side there is not word of any previously "cracked tank". -- (talk) 21:19, 14 November 2012 (UTC) Marco Pagliero Berlin

hazmat suit[edit]

"specifically the requirement for astronauts to wear a Hazmat suit when egressing the vehicle after landing"

can anyone explain the cause of this requirement? Plugwash 00:51, 28 June 2006 (UTC)
NASA routinely uses toxic chemicals for its manouvering thrusters. If the same had been done for the thrusters of the DC-1, then the astronauts would indeed have had to wear hazmat suits. (Though having not seen the design I do not know if that was the intension. It would probably have been simplier for them to use LOX/LOH that was in the main fuel tanks.) I strongly suspect this is a made up excuse because NASA wanted a space plane that looked pretty, rather than a rocket that worked. ANTIcarrot 13:46, 22 November 2006 (UTC)
Well the same would be equally true for any design. How did the VentureStar avoid this in a way that couldn't be adapted to the DC-1?
Having done more research it seems complete BS. It's repeated on the NASA page but never explained, and the DC-Y and SSX pages I've found make no mention of it either. I'm removing it until such time that someone can explain it beyond 'NASA says so'.ANTIcarrot 23:50, 25 May 2007 (UTC)
UDMH Hydrazine fumes are quite toxic. The apollo soyuz crew were exposed to thruster fumes while re-entering and caused a significant medical emergency. given the presence of hydrazine in the shuttle, a little precautions make sense. --Patbahn (talk) 03:47, 21 November 2015 (UTC)

Landing strut failure- sabotage?[edit]

It seems unlikely to me that anyone working on the DC-X would forget to reconnect a hydraulic hose or that the disconnected hose would be missed in a preflight inspection. Also, if it was known the fuel tank was cracked during testing, why was it installed in the vehicle for flight tests?

There's a precedent for that! The LOX tank that exploded on Apollo 13 had been dropped sometime in 1965, damaging a pressure relief vent tube, but it was installed in the SM instead of being repaired or scrapped.

So, deliberate sabotage or more of the "What? Me worry?" attitude and a** covering that's been a factor in killing the three Apollo 1 astronauts and fourteen Shuttle astronauts, and nearly killed three on Apollo 13?

Pffft, come on. Flight crews forget to pull "Remove before flight" tags all the time. Ask any military pilot. I have seen publicity photos for F-16's with the caps protecting the Sidewinder seeker heads clearly in-place (this is bad, they can flap around and smack the forward control surfaces). That's essentially what happened here, no conspiracy theory required. Maury 16:40, 5 January 2007 (UTC)
The Chief Engineer for this program, worked for our company. We had numerous discussions over the landing gear issue, and we worked it as part of our vehicle design process. The Gear design like many items in the vehicle had been done as quickly as possible and with minimum cost design methods at fabrication. Consequently, the design was not approached from an aircraft basis, but, a breadboard basis. The Gear lacked features you would want to see on a operational vehicle such as (Reversible actuation, Dual actuation for locks and actuators, Health Testing,,,) The gear depended upon extreme precision in checklist/procedure following and was subject to manual "Breaking" in order to stow the gear. That procedure was inevitably bound for failure and ultimately did. The gas lines were disconnected as part of a stowing procedure and the technicians were interrupted from reconnecting them by a range issue. 3 of the 4 gear were eyeballed, but that inspection was interrupted by a weather issue. Murphys law would have it that it was the one gear incomplete that was not inspected. --Patbahn (talk) 17:11, 9 November 2010 (UTC)

"a hard landing cracked the aeroshell"[edit]

According to Jordin Kare (who is, I understand, a NASA engineer) here, an in-flight fire had damaged the prototype prior to this occurring, which is possibly more important. This is probably not a good enough source to add the info here, but warrants investigating. JulesH 09:21, 13 November 2006 (UTC)

The only in-flight fire I am aware of occurred during the SDIO text flights, LONG before the accident. The link you included above clearly refers to the last SDIO flight. I believe you are misunderstanding the sequence of events, the fire in question ended SDIO's flights, true, but the craft that flew after that was pretty much all-new. In other words, no, the fire in question was not important in the final accident. Maury 16:40, 5 January 2007 (UTC)
what is probably being referred to is an event early in the flight test program. An explosion from venting crygenic gas (Oxygen) drifted into the exhaust plume from some Ground support equipment.

This cold oxygen cloud met the hot fuel rich exhaust causing a small explosion. The explosion damaged the aeroshell, but fast repairs were conducted by technicians from a subcontractor.

--Patbahn (talk) 03:41, 21 November 2015 (UTC)

DC-XA NASA Final Report[edit]

Concerning the Clipper Graham Mishap Investigation final report dated September 12, 1996,in the summary, reference is made to landing gear 2 brake release control line not connected during flight four. This oversite was listed under the heading of "Primary Cause". Let us please learn from our mistakes and admit the loss of the vehicle was in fact a human error. Recommendations made in the final report included providing up to date hazardous materials information. Six technicians were exposed to the smoke from the explosions of the vehicle. They were not properly informed and as a result required an ambulance response. LGI Group 07:41, 6 February 2007 (UTC)

Thrust units[edit]

Should the engine thrust really be in kgf? Either lbf or N would be more appropriate. 08:53, 9 November 2007 (UTC)

  • Not sure where the data came from. Most likely should be in lbf with metric conversion listed in parathenses. -Fnlayson 16:03, 9 November 2007 (UTC)
There's something wrong anyway. If the mass was roughly 19,000 kg, then the thrust required to lift off ought to have been at least 190,000 N, but the indicated value is only 60 kN, which is less than one third of the minimum required.

-- (talk) 22:24, 25 April 2011 (UTC)

Need to cite "Halfway to Anywhere"[edit]

There needs to be a citation to G. Harry Stine's book "Halfway to Anywhere: Achieving America's Destiny In Space," which covers the development of the DC-X and the whole SSTO program, and the underhanded shenanigans in congress that tried to kill it in the cradle.

Published by M.Evans & Company (March 3, 1998)

ISBN-13: 978-0871318473 (talk) 23:28, 7 September 2011 (UTC)

The DCXA vehicle is currently located in the Museum Support Center building at the New Mexico Museum of Space History On July 21 a restoration project was initiated with a crew of volunteer helpers to make the spacecraft ready for display in time for its 20th anniversary. — Preceding unsigned comment added by (talk) 02:09, 26 July 2012 (UTC)

"Single-stage-to-orbit launcher"?[edit]

Why does the intro describe this rocket as a "single-stage-to-orbit launcher", when it is clearly stated in the corpus that the DC-X was "never intended to reach orbital altitude or velocity"? I suggest replacing it by "prototype of vertical take-off and landing rocket".--Grondilu (talk) 09:20, 10 August 2013 (UTC)

"The difference between the right word and the almost-right word is really quite important; it's the difference between the lightning and the lightning bug" - Mark Twain. The lede doesn't describe DC-X as a "single-stage-to-orbit launcher". It says it was "a...prototype of a single-stage-to-orbit launch vehicle". Which is correct. - The Bushranger One ping only 15:06, 10 August 2013 (UTC)
The DC-X couldn't attain orbital velocities because it was a 1/3rd scale prototype. The full sized design was the DC-Y, which would have enough fuel to achieve orbital velocities. Roidroid (talk) 10:01, 26 July 2015 (UTC)