Author Topic: DIRECT v3.0 - Thread 1  (Read 1286330 times)

Offline Danny Dot

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Re: DIRECT v3.0 - Thread 1
« Reply #3580 on: 07/30/2009 05:11 pm »
snip
We're still thinking of "how to reduce max-Q to get around the problem", whilst Danny now tells us that max-Q is a relatively small part of the problem, thus why Jupiter is also affected.

cheers, Martin

Reducing q does help, but doesn't make the problem go away.  I think the biggest effect is being able to reduce the destruct time from 3 to 2 seconds.

Danny Deger
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Offline engstudent

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Re: DIRECT v3.0 - Thread 1
« Reply #3581 on: 07/30/2009 05:14 pm »
With DIRECT you could put a heavier, more capable abort system on the top, but would cut into what you can take up with the Orion no?   
I haven't been keeping up with the thread lately - has this already been run thru the number crunchers?   ;D
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Offline deltaV

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Re: DIRECT v3.0 - Thread 1
« Reply #3582 on: 07/30/2009 05:40 pm »
The dates which we submitted to Aerospace Corporation were:

Jupiter-130 IOC -- March 2014
Jupiter-241 IOC -- 2018

We've seen some of the results already and without providing specific details, BOTH of those dates have been improved upon to the tune of at least 1 whole year and 2 years respectively -- which we aren't surprised about given that we packed all our schedules with plenty of surplus margins.

I thought the committee stated or implied in one of the recent meetings that none of the options could reduce the gap before 2016 or something like that. Why would they say that if DIRECT can be ready for LEO in 2013? Can we conclude that the committee believes  that Orion is the long pole?

Offline Ben the Space Brit

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Re: DIRECT v3.0 - Thread 1
« Reply #3583 on: 07/30/2009 05:54 pm »
The dates which we submitted to Aerospace Corporation were:

Jupiter-130 IOC -- March 2014
Jupiter-241 IOC -- 2018

(snip)


I thought the committee stated or implied in one of the recent meetings that none of the options could reduce the gap before 2016 or something like that. Why would they say that if DIRECT can be ready for LEO in 2013? Can we conclude that the committee believes  that Orion is the long pole?

I think that they added a huge 'pessimist coefficient' to the schedule to cover MSFC making an utter mess of things.  But, yes, Orion is still a long pole, possibly even more so with the modifications needed to the LAS to enable the crew to survive a SRM unzip.
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Offline ar-phanad

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Re: DIRECT v3.0 - Thread 1
« Reply #3584 on: 07/30/2009 06:20 pm »

There is an extremely serious safety hazard for the NSC abort mode which is under investigation. Remember that the abort motors are less than 10 feet away from the LOX tank on the ET. Remember also that the LOX tank walls are very thin and very pressure sensitive. The safety issue is that at the very instant of ignition of the abort motor, the ignition *shock wave* will disintigrate the LOX tank before the explosive bolts that will free Orion from the SM have even completed their de-couple.That envelops Orion in a cloud of LOX and tank debris with abort motors burning before she even leaves the stack. It's being looked at. No official results yet.

The HLV Crew Abort Assessment (preliminary report - headed by Doug Whitehead) does not mention that. Actually they mention that there are no recontact issue with the ET (page 32). Of course the assessment mentions there is a lot more work to do including "more detailed work on thermal and pressure effects in connection with plume interactions on ET". I however didn't see much on the issue of "shock interactions" other than that in the assessment.

That's what I was remembering earlier, it wasn't a recontact issue, it was the abort motor plume versus the ET hull. I'm just curious to see how this plays out.

Jesse

Offline ar-phanad

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Re: DIRECT v3.0 - Thread 1
« Reply #3585 on: 07/30/2009 06:21 pm »
snip

There is an extremely serious safety hazard for the NSC abort mode which is under investigation. Remember that the abort motors are less than 10 feet away from the LOX tank on the ET. Remember also that the LOX tank walls are very thin and very pressure sensitive. The safety issue is that at the very instant of ignition of the abort motor, the ignition *shock wave* will disintigrate the LOX tank before the explosive bolts that will free Orion from the SM have even completed their de-couple.That envelops Orion in a cloud of LOX and tank debris with abort motors burning before she even leaves the stack. It's being looked at. No official results yet.

Thank goodness.  Plume impingement is a very real threat to the ET.  Protecting the CM for Apollo was a lot of work.

Danny Deger

Is plume impingement an issue for DIRECT as well?

Jesse

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #3586 on: 07/30/2009 06:33 pm »
Ross,

I have probably missed the announcment of your get together tomorrow night.  What time and where is it?

Sadly, my software test will keep me from gonig to the committee session.

Mike

Fishlips restaurant at Port Canaveral. Aiming to be there around 6-6:30pm USB.

Ross
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Offline firehauck

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Re: DIRECT v3.0 - Thread 1
« Reply #3587 on: 07/30/2009 06:34 pm »
Honestly..Do you think the Russians go thru all this to fly ? How many people have they lost...?? How many people have WE lost ?? They draw it up and basically go. I think being Too cautious is a downfall and a waste of time and money. We need to do better than what is happening now  !! If the Shuttle flys OK with it's set up, why do we have to go over this with the Direct configuration. Sure there are dangers but with-out that spaceflight wouldn't be what it is...Pick a design and fly it already !!! No wonder the citizens are losing interest..To much talk, Not enough action  !!!

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #3588 on: 07/30/2009 06:39 pm »
l our schedules with plenty of surplus margins.
Can we conclude that the committee believes  that Orion is the long pole?

That is a fair conclusion.

Ross
« Last Edit: 07/30/2009 06:40 pm by kraisee »
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Offline riney

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Re: DIRECT v3.0 - Thread 1
« Reply #3589 on: 07/30/2009 06:46 pm »

A far as I know it has the same thrust performance as the LAS. 

Danny Deger

But considering it fully encapsulates the CM, I wonder if you could cram enough thermal insulation into MLAS to keep the 'chutes from melting as you fly through the aborted SRB's flaming-cloud-of-death. Assuming you had a launcher that could lift it all, mind.

--riney
« Last Edit: 07/30/2009 06:46 pm by riney »

Offline kraisee

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Re: DIRECT v3.0 - Thread 1
« Reply #3590 on: 07/30/2009 06:47 pm »
Quote from: ar-phanad link=topic=17295.msg450174#msg450174
Is plume impingement an issue for DIRECT as well?

Jesse, it exists on Jupiter, just like on Shuttle, but the design has been done in order to explicity work in that environment.

So, plume impingement still exists, but it is not a 'problem' on this vehicle.

Ross
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Offline ar-phanad

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Re: DIRECT v3.0 - Thread 1
« Reply #3591 on: 07/30/2009 07:25 pm »
Quote from: ar-phanad link=topic=17295.msg450174#msg450174
Is plume impingement an issue for DIRECT as well?

Jesse, it exists on Jupiter, just like on Shuttle, but the design has been done in order to explicity work in that environment.

So, plume impingement still exists, but it is not a 'problem' on this vehicle.

Ross

Is this in reference to the base heating near the SSME? Or the LAS motors tearing into the ET during abort sequence? Danny's comment about plume impingement was preceded by a discussion pertaining to NSC's potential "show-stopper."

Sorry if I've over-complicated this!

Jesse

Offline engstudent

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Re: DIRECT v3.0 - Thread 1
« Reply #3592 on: 07/30/2009 07:28 pm »
3 minute DIRECT presentation just done by a KSC Engineer during the public comments section at the Augustine commissions Cocoa Beach meeting.

"Continuing working full speed on a project that is doomed for failure is demoralizing and frustrating." 

"DIRECT, just right"
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Offline mr.gold

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Re: DIRECT v3.0 - Thread 1
« Reply #3593 on: 07/30/2009 08:02 pm »
The problem, when addressing the Augustine Commission, is that you guys do not sell this idea. This is the optimal solution. This needs to be packaged and sold.

I attempted to contact Norman Augustine through his personal secretary at the Board of Regents for the Maryland University system. I wrote a lengthy report and forwarded it to his secretary. She assured me that she would forward that to Mr. Augustine. I do not know if I got through.

The letter stated some of the following...

The truth is that there does not need to be a Manned Spaceflight LEO gap if the Direct avenue is chosen. The physical geometries of the Pads 39A and 39B, the interior of the VAB, and the support facilities at Michoud and Nevada do not have to be changed all that much. The Shuttle can continue to fly while Direct 3.0 is being developed. From a point of Nat'l Security we do not need to depend upon Russian Soyuz for rides while our newest vehicle is being developed.

That is an important sales pitch...which was not used in any of the presentations. Please use it and let's get the Direct approach on the road...to save us time, bucks, and keep us flying. Thanks.

Mr.Gold
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Offline fotoguzzi

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Re: DIRECT v3.0 - Thread 1
« Reply #3594 on: 07/30/2009 08:30 pm »
That is an important sales pitch...which was not used in any of the presentations.
(I am not a DIRECT teammember.)  The Augustine presentation was a 20-minute recitation of a 30-minute presentation that was itself an abridgement of a 60-minute presentation from a month before.

I believe you will find your points answered in the long presentation.  Further, DIRECT has met with the Aerospace Corporation in person and in followup correspondence. 

I believe that DIRECT has got the full message to the people who count.

(Oh, and they met with the Obama administration during the transition period.)

Modify: typo
« Last Edit: 07/30/2009 11:32 pm by fotoguzzi »
My other rocket is a DIRECT Project 2

Offline robertross

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Re: DIRECT v3.0 - Thread 1
« Reply #3595 on: 07/30/2009 09:56 pm »

Conversely, I see your point - throttling-down the SSME's (through to max-Q, not SRB burnout) seems to me like it should reduce max-Q.

But Danny's later post has covered this:-

400 psf is better than 1200 psf, but even that low dynamic pressure does not solve the problem.

I think the confusion here is this started out as "an Ares I problem, because of the very high max-Q pressures".

We're still thinking of "how to reduce max-Q to get around the problem", whilst Danny now tells us that max-Q is a relatively small part of the problem, thus why Jupiter is also affected.

cheers, Martin

Ah okay...

Wow, even 400 psf is high. Well, let's put it this way: if it's bad for Direct, it's bad for EVERYONE ELSE.

I'll play devil's advocate for once and say: NASA can (and must) solve this one  :)

Offline clongton

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Re: DIRECT v3.0 - Thread 1
« Reply #3596 on: 07/30/2009 10:07 pm »

Conversely, I see your point - throttling-down the SSME's (through to max-Q, not SRB burnout) seems to me like it should reduce max-Q.

But Danny's later post has covered this:-

400 psf is better than 1200 psf, but even that low dynamic pressure does not solve the problem.

I think the confusion here is this started out as "an Ares I problem, because of the very high max-Q pressures".

We're still thinking of "how to reduce max-Q to get around the problem", whilst Danny now tells us that max-Q is a relatively small part of the problem, thus why Jupiter is also affected.

cheers, Martin

Ah okay...

Wow, even 400 psf is high. Well, let's put it this way: if it's bad for Direct, it's bad for EVERYONE ELSE.

I'll play devil's advocate for once and say: NASA can (and must) solve this one  :)

But the lower dynamic pressure on the Jupiter provides options that the Ares doesn't have; specifically the ability to pull Orion much further away from the vehicle in an abort. Our initial analysis shows that if Orion aborted off a Jupuiter it would be in the safe zone; not by much, but safe. Since then we have refined the abort trajectories and have added additional distance between the SRB's and the aborted Orion. And that still leaves us the option, which Ares doesn't have, of a more powerful LAS to take Orion even further away.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline Pheogh

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Re: DIRECT v3.0 - Thread 1
« Reply #3597 on: 07/30/2009 10:17 pm »
The dates which we submitted to Aerospace Corporation were:

Jupiter-130 IOC -- March 2014
Jupiter-241 IOC -- 2018

We've seen some of the results already and without providing specific details, BOTH of those dates have been improved upon to the tune of at least 1 whole year and 2 years respectively -- which we aren't surprised about given that we packed all our schedules with plenty of surplus margins.

I thought the committee stated or implied in one of the recent meetings that none of the options could reduce the gap before 2016 or something like that. Why would they say that if DIRECT can be ready for LEO in 2013? Can we conclude that the committee believes  that Orion is the long pole?

What is especially troubling to me even more, is that especially after today, there seems to be this mounting consensus that if we extend shuttle and ISS we lose exploration outside of LEO?

This runs completely opposite of what DIRECT presented to the committee. So where is the disconnect? cost, schedule or both. What am I missing here? Ross?

Offline Drapper23

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Re: DIRECT v3.0 - Thread 1
« Reply #3598 on: 07/30/2009 10:31 pm »
http://www.space.com/news/090730-ft-moon-budget.html   Augustine Committee Says Moon Within Reach

Offline Lobo

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Re: DIRECT v3.0 - Thread 1
« Reply #3599 on: 07/30/2009 10:50 pm »
http://www.space.com/news/090730-ft-moon-budget.html   Augustine Committee Says Moon Within Reach

Dunno, it also says this:

"The Obama administration's 2010 budget for NASA represents a $26.5 billion cut from previous projections.

Gary Pullium, a vice president with The Aerospace Corp., said NASA won't be able to return to the moon by 2020 under those constraints. "Given our assessment of the 2010 budget and what we believe about cost and schedule, we just simply said there is not enough money in this budget in the near term to do the human lunar return," he said."

Does he mean we can't go back by 2020 under Obama's budget cuts at all?  Or just with the current Ares program?

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