DIRECT v3.0 - Thread 1

[Drapper23]

Death Knell for NASA's Ares 1 Rocket   http://www.newscientist.com/blogs/shortsharpscience/2009/07/death-knell-for-nasas-ares-roc.html   The article states that the USAF SRB study will also kill the Direct Launcher. Ross, What is you SRB explosion analysis showing for the Direct Launcher? I know that your preliminary analysis showed that it(Direct launched CEV) can survive a SRB explosion,but what is your more detailed analysis showing?

[TrueBlueWitt]

Death Knell for NASA's Ares 1 Rocket   http://www.newscientist.com/blogs/shortsharpscience/2009/07/death-knell-for-nasas-ares-roc.html   The article states that the USAF SRB study will also kill the Direct Launcher. Ross, What is you SRB explosion analysis showing for the Direct Launcher? I know that your preliminary analysis showed that it(Direct launched CEV) can survive a SRB explosion,but what is your more detailed analysis showing?

The great thing about DIRECT is.. with all those Tons of excess margin.. you can always put a big enough LAS on it to clear the SRB explosion. 

No chance you can put a bigger LAS on the STICK.. at least not wtihout leaving EVERYTHING inside Orion in the parking lot.. including the crew.

[Lancer525]

Or maybe this:

One thing I would like to suggest...

Instead of "3-4 SSME" make it clearer by saying "3 or 4 SSME"

Initially, I saw it as "three-fourths SSME" even though it wasn't a slash. Let's take the confusion out and do the simplest thing first.

[MP99]

Death Knell for NASA's Ares 1 Rocket   http://www.newscientist.com/blogs/shortsharpscience/2009/07/death-knell-for-nasas-ares-roc.html   The article states that the USAF SRB study will also kill the Direct Launcher. Ross, What is you SRB explosion analysis showing for the Direct Launcher? I know that your preliminary analysis showed that it(Direct launched CEV) can survive a SRB explosion,but what is your more detailed analysis showing?

This appears to be a deduction by "Henry Spencer, computer programmer, spacecraft engineer and amateur space historian".

There's no doubt this is a serious issue, but I'm not sure he's in a position to speak authoritatively on this issue. Of course, he may have inside info, but doesn't seem to claim so.

cheers, Martin

[Danny Dot]

Death Knell for NASA's Ares 1 Rocket   http://www.newscientist.com/blogs/shortsharpscience/2009/07/death-knell-for-nasas-ares-roc.html   The article states that the USAF SRB study will also kill the Direct Launcher. Ross, What is you SRB explosion analysis showing for the Direct Launcher? I know that your preliminary analysis showed that it(Direct launched CEV) can survive a SRB explosion,but what is your more detailed analysis showing?

IIRC the Air Force analysis says at the lower dynamic pressure of Direct, it should be OK.  I am working a 3 DOF simulation as we speak.

Danny Deger

[Herb Schaltegger]

This appears to be a deduction by "Henry Spencer, computer programmer, spacecraft engineer and amateur space historian".

Google the name.  Henry knows more about spacecraft design and history than nearly anyone else I've ever known, despite the "amateur" title.  The virtual "I Corrected Henry" t-shirts were given out very, very rarely in the heydays of the Usenet sci.space.* discussion groups.

His criticisms are generally valid but of course, until the analysis is done they may not be in this case.

[Drapper23]

Danny, Have the Augustine Committee and/or The Aerospace Corporation been given any of the Direct technical data that verifies that the Direct Launched CEV(CM) can survive a SRB explosion?

[dlapine]

IIRC the Air Force analysis says at the lower dynamic pressure of Direct, it should be OK.  I am working a 3 DOF simulation as we speak.

Danny Deger

Excellent. I posted a reply on the NewScientist that:

1) the Direct program was aware of the issue and looking at it

2) the Direct launcher had a much lower Max Q and might not be affected this

3) and the Direct launcher had large enough margins to deal any necessary modifications, if it came to that.

These would imply that the author's conclusions weren't valid for Direct, his personal knowledge of spacecraft design notwithstanding.

Edited: for grammar

[jeff.findley]

This appears to be a deduction by "Henry Spencer, computer programmer, spacecraft engineer and amateur space historian".

Google the name.  Henry knows more about spacecraft design and history than nearly anyone else I've ever known, despite the "amateur" title.  The virtual "I Corrected Henry" t-shirts were given out very, very rarely in the heydays of the Usenet sci.space.* discussion groups.

His criticisms are generally valid but of course, until the analysis is done they may not be in this case.

Absolutely true.

[bad_astra]

There's no doubt this is a serious issue, but I'm not sure he's in a position to speak authoritatively on this issue. Of course, he may have inside info, but doesn't seem to claim so.

cheers, Martin

You've got to be kidding me. Henry Spencer knows what he's talking about.

[Mark S]

Or maybe this:

One thing I would like to suggest...

Instead of "3-4 SSME" make it clearer by saying "3 or 4 SSME"

Initially, I saw it as "three-fourths SSME" even though it wasn't a slash. Let's take the confusion out and do the simplest thing first.

I have no graphic skills, but how about this:  Put the image of the Common Core in the middle, and have one arrow going left with the text "Core w/3 SSMEs, no upper stage", and another arrow going right with the text "Core w/4 SSMEs plus upper stage".  That should cover everything, right?

Maybe have no PLF or stage above the Common Core in the middle, just maybe the words "Common Core".

Mark S.

[dlapine]

There's no doubt this is a serious issue, but I'm not sure he's in a position to speak authoritatively on this issue. Of course, he may have inside info, but doesn't seem to claim so.

cheers, Martin

You've got to be kidding me. Henry Spencer knows what he's talking about.

From his Wikipedia entry-

"He is a highly regarded space enthusiast and historian, and is a familiar and respected presence on several space forums, including Usenet and the Internet. From 1983 to 2007 Spencer has posted over 34000 message to the sci.space.* newsgroups. His knowledge of space history and technology is such that the "I Corrected Henry Spencer" virtual T-shirt award was created as a reward for anyone who can catch him in an error of fact. Thus far, there are few winners."

Great, this is the guy I try to correct.

Well, let's hope that in this case, he just didn't have enough information. Any expert can reach the wrong conclusion if denied enough information.

[Drapper23]

Danny, What do the initials IIRC mean?

[marsavian]

He's wrong now in blankly stating all SDLVs will terminally suffer from this problem. It's only Ares I with its high max-q and zero effective margins that's been mortally wounded whether MSFC realizes it or not.

[lewis886]

HARRY SPENCER vs. JIM in a steel cage match!!!   

(hehe)


EDIT:  but seriously though... i would be interested in Jim's opinion of this...  does he think this could be a serious enough issue to jettison the entire SRB-shuttle derived idea? 

[dlapine]

Danny, What do the initials IIRC mean?

internet slang

If I recall correctly

[marsavian]

HARRY SPENCER vs. JIM in a steel cage match!!!   

(hehe)

No contest, Jim on a TKO. He's a real spacecraft engineer .

[gospacex]

It looks like LAS does not need to be made more powerful regarding thrust, it just needs to have a "sustainer" tailoff to pull Orion farther from the hot debris cloud. This should be relatively easy to do, since DIRECT has plenty of margins.

[Herb Schaltegger]

HARRY SPENCER vs. JIM in a steel cage match!!!   

(hehe)

No contest, Jim on a TKO. He's a real spacecraft engineer .

Actually, Henry is too these days (or was; he did work on a Canadian satellite program, IIRC). 

In either case, Henry's an incredibly bright guy but isn't infallible.  Remember, this is a pretty specific issues here: the capability of the LAS to pull an Orion away from the stack during and around the period of max-q.  Lower the max-q, beef up the LAS (neither of which is possible for Ares I) and the problem should pretty much go away, especially given the statistical likelihood of the kinds of failure we're talking about here.

[clongton]

Death Knell for NASA's Ares 1 Rocket   http://www.newscientist.com/blogs/shortsharpscience/2009/07/death-knell-for-nasas-ares-roc.html   The article states that the USAF SRB study will also kill the Direct Launcher.

IIRC the Air Force analysis says at the lower dynamic pressure of Direct, it should be OK.  I am working a 3 DOF simulation as we speak.

Danny Deger

Henry Spencer does know what he's talking about - *usually*; but NOT in this case. We have had no contact with him and he has made no inquiries for data. He does not know or understand DIRECT and has made no attempt to educate himself about it before speaking. He has offered NO data to substantiate his claim except for the USAF report, which was exclusively about Ares-I, not DIRECT. His conclusion about DIRECT is a leap of faith and an unwarranted extension of non-applicable data based solely on the Ares-I report. It completely ignores the fact that the USAF itself has indicated that a vehicle with a much lower dynamic pressure for max-q would likely be alright. Our own analysis has already indicated that both Jupiters, with far lower dynamic pressures are in the safe zone and Orion would survive the event.

Mr. Spencer is apparently expressing his own *well-known* preference for the all-EELV solution.