Author Topic: DIRECT v2.0 - Thread 4  (Read 61515 times)

Offline kraisee

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DIRECT v2.0 - Thread 4
« on: 05/21/2009 11:15 AM »
This is going to be the final thread for DIRECT v2.0.

But until we actually announce v3.0 at ISDC in a little over a week's time I'm still going to create this new thread because the last one has just hit the 250 page mark!

I can hardly believe just how many messages are in these five main DIRECT threads so far, but I think its a testament to the general interest level in the proposal that they keep growing to such lengths.   Thanks to everyone who has taken part and also to those who quietly lurk here too.

Ross.
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Offline zapkitty

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Re: DIRECT v2.0 - Thread 4
« Reply #1 on: 05/21/2009 11:23 AM »
I suppose the Oreo-powered SRB's are still a no-go?

Offline kraisee

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Re: DIRECT v2.0 - Thread 4
« Reply #2 on: 05/21/2009 11:57 AM »
Sadly we just couldn't make the Oreo-powered SRB's work in this configuration.

We had all sorts of problems with de-bonding between the cookie and the cream layers, and for some peculiar reason the test samples always seemed to be short of the required filler!   We checked the quantities at the factory and again upon delivery, but by the time they arrived at the launch site most of the creme had vanished...   We were never able to find out why...   Such a pity.

:)

Ross.
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Offline engstudent

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Re: DIRECT v2.0 - Thread 4
« Reply #3 on: 05/21/2009 11:58 AM »
I suppose the Oreo-powered SRB's are still a no-go?


got milk?   ;D
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Offline strangequark

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Re: DIRECT v2.0 - Thread 4
« Reply #4 on: 05/21/2009 12:20 PM »
I suppose the Oreo-powered SRB's are still a no-go?


I think that Hydrox cookies show promise though. Always did think that those sounded like a rocket propellant.


Quote from: robertross

From my own point of view, if I was designing a rocket and my manager said we are going with tried and true existing rockets...I would probably kiss them. The challenges of designing a rocket only get compounded when you add major unknowns like engine performance, attachment points, plumbing...

Going with an off-the-shelf engine saves you MONTHS of time right at the start. Just look at J-2X:

1. No 'firm' performance numbers
2. No 'firm' mass
3. No 'firm' availability date
4. No 'firm' environment data (acoustics, vibrations, thermal issues...)

All they have is data from an old design to go with.

And if that wasn't enough, just think of what might crop up with the new 5-segment rocket motor. It might be okay, but it might not (for Orion/Ares-I at least).

Oh, don't get me wrong. I absolutely agree that it is exciting. It's a real tribute to the Shuttle and EELV programs that you can build a 100mT exploration class vehicle almost completly from existing systems. I'm apt to kiss Ross and team myself. I was just trying to get an inkling as to exactly how far up the chain and into places outside of the DIRECT family that excitement had spread.
« Last Edit: 05/21/2009 12:31 PM by strangequark »

Offline rsp1202

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Re: DIRECT v2.0 - Thread 4
« Reply #5 on: 05/21/2009 01:05 PM »
I suppose the Oreo-powered SRB's are still a no-go?


I think that Hydrox cookies show promise though.

You Oreo/Hydrox fanboys will help defeat the law of physiques.

Offline William Barton

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Re: DIRECT v2.0 - Thread 4
« Reply #6 on: 05/21/2009 01:14 PM »
Sadly we just couldn't make the Oreo-powered SRB's work in this configuration.

We had all sorts of problems with de-bonding between the cookie and the cream layers, and for some peculiar reason the test samples always seemed to be short of the required filler!   We checked the quantities at the factory and again upon delivery, but by the time they arrived at the launch site most of the creme had vanished...   We were never able to find out why...   Such a pity.

:)

Ross.

That's the problem with you engineering types: you think it's all in the numbers. Science doesn't hold all the answers. Why do you think Keebler employs elves?

Offline Ben the Space Brit

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Re: DIRECT v2.0 - Thread 4
« Reply #7 on: 05/21/2009 01:30 PM »
This was originally posted over on the rebuttal thread.  However, that wasn't really the right thread for it, so I've decided to put it here.

A poster using the handle JIS said that there are unique issues and problems with the Jupiter LV system, one of which is that it baselines a two-launch strategy for delivery of cargo to the lunar outpost.  I have to agree with JIS that one-launch robot cargo LSAM to the Moon should be regarded as a baseline capability of an HLLV, even if only for budgetary reasons.  So, with that said, what are we asking of our HLLV to do such a thing? Can we get something like a Jupiter to do it?

Remember that Ares-V has a lot of extra launch capability because its EDS is a dual-duty stage.  As well as carrying a cargo LSAM through TLI it also has to carry a manned LSAM, Orion & consumables (~25t extra, plus margins) through TLI after also having carried the LSAM up to LEO.  DIRECT can avoid that by switching to 2-launch for manned missions, where the EDS has no real payload during launch.  There has got to be some weight savings there.

It occurs to me that a HLLV powerful enough to launch a LSAM-C through TLI with one launch could also launch a LSAV with one launch.  You thus have a one-launch outpost crew rotation.

So, how about it? Is it possible to get performance out of the J-232 or JS-246 (or any other J-2xx permutation) to get such capabilites?

To summarise, what we are looking for from our HLLV is:
* 1-launch cargo to lunar outpost;
* 1-launch crew rotation to lunar outpost using LSAV;
* 2-launch manned lunar excursion;
* 2-launch NEO encounter;
* 3-launch Mars mission (including LEO refuelling).

Let's remember that 1-launch lunar cargo is going to be a second-generation requirement for the HLLV.  So, we can play around with ideas that would slow down the delivery of the vehicle if we wanted them in the initial return-to-the-Moon launcher (the way NASA is with Ares-V).  We can play with, the RS-68B(r), the 5-seg, J-2X, composite-hulled expendable SRBs and third stages.

Just to re-introduce an old idea of mine (I don't know how practical it would be): JS-3571H - 5 x SSME core + 5-seg RSRMs, 7 x RL-10B-2 mid-stage, 1 x J-2X EDS.  Call it Jupiter-V. ;D This was the result of a late-night brainstorm on my part whilst trying to develop a single-launch lunar manned archetecture from the basis of the Jupiter series.  Basically, it is essentially intended to launch a CEV, LSAM and EDS into LEO with enough fuel for TLI without any rendezvous. 

[EDIT for clarity)
« Last Edit: 05/21/2009 01:31 PM by Ben the Space Brit »
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Offline TrueBlueWitt

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Re: DIRECT v2.0 - Thread 4
« Reply #8 on: 05/21/2009 01:42 PM »
This was originally posted over on the rebuttal thread.  However, that wasn't really the right thread for it, so I've decided to put it here.

A poster using the handle JIS said that there are unique issues and problems with the Jupiter LV system, one of which is that it baselines a two-launch strategy for delivery of cargo to the lunar outpost.  I have to agree with JIS that one-launch robot cargo LSAM to the Moon should be regarded as a baseline capability of an HLLV, even if only for budgetary reasons.  So, with that said, what are we asking of our HLLV to do such a thing? Can we get something like a Jupiter to do it?

Remember that Ares-V has a lot of extra launch capability because its EDS is a dual-duty stage.  As well as carrying a cargo LSAM through TLI it also has to carry a manned LSAM, Orion & consumables (~25t extra, plus margins) through TLI after also having carried the LSAM up to LEO.  DIRECT can avoid that by switching to 2-launch for manned missions, where the EDS has no real payload during launch.  There has got to be some weight savings there.

It occurs to me that a HLLV powerful enough to launch a LSAM-C through TLI with one launch could also launch a LSAV with one launch.  You thus have a one-launch outpost crew rotation.

So, how about it? Is it possible to get performance out of the J-232 or JS-246 (or any other J-2xx permutation) to get such capabilites?

To summarise, what we are looking for from our HLLV is:
* 1-launch cargo to lunar outpost;
* 1-launch crew rotation to lunar outpost using LSAV;
* 2-launch manned lunar excursion;
* 2-launch NEO encounter;
* 3-launch Mars mission (including LEO refuelling).

Let's remember that 1-launch lunar cargo is going to be a second-generation requirement for the HLLV.  So, we can play around with ideas that would slow down the delivery of the vehicle if we wanted them in the initial return-to-the-Moon launcher (the way NASA is with Ares-V).  We can play with, the RS-68B(r), the 5-seg, J-2X, composite-hulled expendable SRBs and third stages.

Just to re-introduce an old idea of mine (I don't know how practical it would be): JS-3571H - 5 x SSME core + 5-seg RSRMs, 7 x RL-10B-2 mid-stage, 1 x J-2X EDS.  Call it Jupiter-V. ;D This was the result of a late-night brainstorm on my part whilst trying to develop a single-launch lunar manned archetecture from the basis of the Jupiter series.  Basically, it is essentially intended to launch a CEV, LSAM and EDS into LEO with enough fuel for TLI without any rendezvous. 

[EDIT for clarity)

Seems to me you'd be better putting your J-2X on a new mid stage.. and then perhaps remove a few RL-10B-2s from the EDS..

Not sure what adding another stage does for LOM however.

I believe DIRECT's answer to One launch lunar missions is to use a propellant depot.  From what I remember, you can put significantly more cargo mass on the moon than Ares-V with a single JS-246 launch and using a depot to fuel the EDS.  Ross or Chuck can tell you by how much.

Edit: can't spell to save my life today..
« Last Edit: 05/21/2009 01:45 PM by TrueBlueWitt »

Offline LMSenus

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Re: DIRECT v2.0 - Thread 4
« Reply #9 on: 05/21/2009 01:55 PM »
I can hardly believe just how many messages are in these five main DIRECT threads so far, but I think its a testament to the general interest level in the proposal that they keep growing to such lengths.   Thanks to everyone who has taken part and also to those who quietly lurk here too.

Ross.

Ross, as one of those who "quietly lurks" for the most part, I can tell you that DIRECT is the reason I came to NSF (and joined L2).  I read about the project in Popular Mechanics (how many others too?), and that sent me here.  After all I've read, I really believe DIRECT is the way to go.  The fact that you guys have done all this on your own time is amazing.  It's not too often that, instead of just complaining about the status quo, folks get off their butts and really *DO* something about the problem.  You're all to be commended.

Now I'll go back to quietly lurking  ;)
"There's a duty to the truth. Especially for an engineer." -- nooneofconsequence, 4/1/09
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Stop the madness!  We need to go DIRECT-ly to the moon...and beyond.

Offline guru

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Re: DIRECT v2.0 - Thread 4
« Reply #10 on: 05/21/2009 01:57 PM »
Something worth noting is that JIS's contention is centered mostly on the increase in LSAM mass.  I would counter that it doesn't matter how much the lander weighs if the rocket to launch it can't be afforded.

As a casual bystander, I don't know if I would care if the resupply mission took one launch or two, as long as my taxes weren't any higher. Two Jupiter launches can put more on the surface than one Ares V can, and the rockets cost less than half as much (when amortized, which is what matters), so price wise, you come out ahead per unit of mass placed on the surface.

The Orion capsule may be somewhat oversized for four people, but it was originally (and still is to some extent) designed to carry 6 people comfortably for LEO missions and (unofficially) for Earth return landings from Mars.  It could carry six people to lunar orbit as well, but the lunar lander isn't designed to accomodate that many people, so there's no point in taking them.

Offline Swatch

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Re: DIRECT v2.0 - Thread 4
« Reply #11 on: 05/21/2009 01:58 PM »
I suppose the Oreo-powered SRB's are still a no-go?


I think that Hydrox cookies show promise though.

You Oreo/Hydrox fanboys will help defeat the law of physiques.


I've been sucker PUN-ched!

*groan.....*
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Offline William Barton

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Re: DIRECT v2.0 - Thread 4
« Reply #12 on: 05/21/2009 02:06 PM »
Part of the point of DIRECT working the way it does is to demostrate the Orion/Altair mission can be accomplished more cheaply and quickly using something other than the Stick I + Godzilla VII architecture. Accepting Little CEV + Big LSAM is a baseline handicap that purposely allows and apple-to-apples comparison. I personally don't think the argument against ESAS is winnable on anything but a dollars-to-doughnuts basis (how many doughnuts can you buy with the money you have). I guess we'll see, soon enough.

That said, if you were going to have 1-launch lunar cargo and 1-launch LSAV in your architectural path, then it might make sense to choose lunar surface rendezvous as you architecture in the first place and save on development time/$$$. I'd actually prefer that, even though the "safety" arguments against it are many and varied, but it's not going to happen. DIRECT merely shows a cheaper, quicker way to accomplish EOR-LOR.

Offline Danny Dot

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Re: DIRECT v2.0 - Thread 4
« Reply #13 on: 05/21/2009 02:49 PM »
On me being a front man for Direct, until and if it is well know NASA was indeed dysfunctional when I left in 2005, I would certainly be labeled as a disgruntled employee.  I would not make a good front man for Direct.

Danny Deger
Danny Deger

Offline cgrunska

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Re: DIRECT v2.0 - Thread 4
« Reply #14 on: 05/21/2009 05:18 PM »
I came to NSF as well for Direct, back in November i think.

i've learned a lot about space since then

You guys rock. Can't wait till september!

Offline Cale

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Re: DIRECT v2.0 - Thread 4
« Reply #15 on: 05/21/2009 08:11 PM »
Hi Ross,

Just downloaded your "baseball cards" (great term, BTW) for the SSME versions of the Jupiter launch systems.

I realize you're trying to limit discussions to Direct but have a question regarding "core burn time" for the J130 that I'm trying to implement into Orbiter using Antonio's add-on.  If there's another forum thread for this, I'll gladly move over there.

Does the 508.1 second burn time account for the throttle-down that occurs late in the flight (to reduce G-loads), or is it based on 104.5% power all the way through?  Am trying to configure the autopilot to work properly using the specs you've provided.

Best of luck at the conference!  I've been lurking for quite a few months on this thread and have my fingers crossed that saner heads prevail and Direct is chosen for VSE.

Best,

Cale

Offline butters

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~
« Reply #16 on: 05/21/2009 08:51 PM »
The vigorous distancing from propellant transfer in the rebuttal document got me thinking about growth options along the transition to a true depot architecture. 

The baseline architecture is limited by 100 mT of post-ascent TLI propellant remaining in an EDS sized for 175 mT.  The following profiles make use of otherwise offloaded or unnecessary upper stages to lift TLI propellant and the additional payload mass this permits.


2x: First launch 100 mT of TLI propellant on J-24x as per baseline.  Then launch CEV, LSAM, and EDS on J-24x.  The excess performance of the baseline CLV is used for more payload and the TLI propellant it requires.  The complete stack rendezvous with the first JUS and fuels up the EDS.  This profile doesn't allow for a whole lot of growth, but it does eliminate the unusual LSAM "rear rendezvous" and replace it with a propellant transfer maneuver that is probably much more applicable to future mission requirements.

2.5x: First launch as per baseline.  Then launch LSAM and EDS on J-24x, using the lack of CEV/LAS plus excess performance to add more payload and TLI propellant.  Rendezvous and propellant transfer before launching CEV on EELV Heavy or perhaps J-130 initially.  This profile would allow for significant LSAM growth, and LOC is improved because the propellant transfer is completed without the CEV present.

3x: First launch as per baseline.  Then launch LSAM on J-24x as before, except the JUS and its post-ascent propellant will be a lunar insertion/deorbit crasher stage.  Finally launch CEV and EDS on J-24x, leaving about 70 mT of post-ascent propellant.  After propellant transfer, the EDS tanks should be nearly full, optimizing mass through TLI, and the crasher stage would help optimize mass to the lunar surface.  The crew is present for propellant transfer, though.


The 2x profile is probably more trouble than it's worth.  The 2.5 profile is much more compelling, including cargo missions.  It establishes EELV as the CLV architecture for LEO and beyond, and crew exposure to on-orbit maneuvers is reduced to match Constellation.  The 3x profile is interesting and potentially promising, but it's also riskier.

Thoughts?
« Last Edit: 05/21/2009 09:03 PM by butters »

Offline zapkitty

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Re: ~
« Reply #17 on: 05/21/2009 09:53 PM »
Thoughts?

The elephant in the rooms is the SRB composition. Sooner or later the EPA will be forced to deal with the environmental impact of SRB's releasing HSO (hydrogenated soybean oil) into the environment and especially the water.

Oh... you mean that other thing?  Even a small propellant depot would work better and cheaper, no?

Offline madscientist197

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Re: DIRECT v2.0 - Thread 4
« Reply #18 on: 05/22/2009 12:37 AM »
The SRB composition issue is big, but I doubt it would mean the end of solids. All it would mean is a 10s drop in ISP when they change to a NH4NO3 based oxidiser. I bet a lot of people would celebrate the removal of HCl from the exhaust and all the associated concerns (maintance of structures, water pollution etc.).
« Last Edit: 05/22/2009 12:37 AM by madscientist197 »
John

Offline Lampyridae

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Re: DIRECT v2.0 - Thread 4
« Reply #19 on: 05/22/2009 02:54 AM »
The SRB composition issue is big, but I doubt it would mean the end of solids. All it would mean is a 10s drop in ISP when they change to a NH4NO3 based oxidiser. I bet a lot of people would celebrate the removal of HCl from the exhaust and all the associated concerns (maintance of structures, water pollution etc.).

Switching to Kerolox to me would be the better move, as and when this becomes any issue. Energia did it without any problems. And even those were recoverable! Of course there has to be a domestic engine supplier...
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