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SLS / Orion / Beyond-LEO HSF - Constellation => Heavy Lift Launch Vehicle (HLV/SLS) => Topic started by: kraisee on 05/10/2007 08:41 PM

Title: DIRECT v2.0
Post by: kraisee on 05/10/2007 08:41 PM
Announcing:
 
DIRECT Goes Live – version 2.0
 
www.directlauncher.com
 
10th May 2007
Cape Canaveral, FL
 
Today the team behind the 2006 DIRECT proposal issues a newly revised study seeking to persuade NASA to re-examine the decision to use two completely different Ares launchers to support NASA's new mandate of returning humans to the moon and taking them to explore the rest of our solar system.
 
At the end of last year, Dr. Doug Stanley, author of NASA’s Exploration Systems Architecture Study (ESAS) Report provided a critique of the version 1 proposal. This revision is a direct result of that critique. All of his comments respecting the Direct launch vehicle were taken seriously, and the entire proposal was re-evaluated in that context.
 
After months of revised calculations, updates, feedback, and critical analysis of the constantly changing situation surrounding the Vision for Space Exploration, our new study identifies a launch vehicle even more closely matched to existing hardware, which we have named the "Jupiter" launch vehicle. Able to double Ares-I's payload performance to stable Low Earth Orbit, "Jupiter" scales, with the use of an upper stage and a 3rd engine, to also produce true heavy lift payload performance greater than 100 tons per flight.
 
This means that this single launch vehicle is capable of accomplishing all the roles expected of the two Ares vehicles, yet does so for less than half the development costs and on a faster schedule.
 
Specifically addressing concerns with our first proposal, we have selected only existing flight-proven engines to power the Jupiter, specifically the Space Shuttle's 4-segment SRB's and a man-rated version of the RS-68 from the Delta-IV program with no performance enhancements what-so-ever.
 
Our optional upper stage is powered by the lower specification J-2X "D" engine variant, but is not required to support the early ISS missions.   The new engines are now not required until the lunar phase of the Jupiter program – beginning around 2017.   This reduces the scheduling pressures and high investment costs currently plaguing Ares-I development while Shuttle operations continue.
 
"Jupiter" removes all of the key "long lead time" from the near-term budget, which would allow NASA, in these lean times, to afford to fund other important programs once again, while still accomplishing all of the VSE's objectives and importantly, doing so ahead of schedule.
 
With Jupiter as its new backbone, and with DIRECT's architecture, NASA could close the Shuttle/Orion gap to just two years, save half of its launch vehicle development costs over the next 10 years, while also benefiting from an increase in 2-launch lunar mission performance by as much as 42% compared to existing plans with Ares-I and Ares-V.
 
While DIRECT's architecture guarantees lunar access with NASA's very first new launch vehicle, the ultimate goal of the gargantuan Ares-V is not removed from the table - it remains a logical upgrade option for the future, because "Jupiter" does not cost any more to develop than Ares-I, yet Jupiter would benefit the Ares-V by pre-qualifying the RS-68 and the J-2XD engines, and creating a versatile Earth Departure Stage – all of which the Ares-V could utilize.
 
To learn more about the DIRECT Architecture and the Jupiter launcher, please visit our website at: www.directlauncher.com
Title: RE: DIRECT v2.0
Post by: RedSky on 05/10/2007 09:02 PM
To all involved in Direct 2... looks great.  But just a suggestion based on the intended audience: switch to American English spelling rather than UK English (e.g., maneuver for manoeuvre, etc.).  ;)
Title: RE: DIRECT v2.0
Post by: marsavian on 05/10/2007 09:23 PM
Have you sent it to Michael Griffin again ? Maybe a copy to Doug Stanley (and Scott Horowitz) might be good too. Keep trying guys, I think either Ares I/V or DIRECT would do the job but yours looks cheaper and quicker if maybe slightly less safer. However with a looming Democrat President I would say DIRECT remains the only feasible political and economic one given the less enthusiasm to manned spaceflight they have with the obvious squeeze on funds that will produce which will mean the Chinese will get there first and take all the helium-3 while the Democrats drone on about Science and saving the Earth ;-).
Title: RE: DIRECT v2.0
Post by: Chris Bergin on 05/10/2007 09:25 PM
Quote
RedSky - 10/5/2007  10:02 PM

To all involved in Direct 2... looks great.  But just a suggestion based on the intended audience: switch to American English spelling rather than UK English (e.g., maneuver for manoeuvre, etc.).  ;)

I've learnt to do that. Got to cater to your main audience :)
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/10/2007 09:45 PM
What's the Jupiter 242? I couldn't find it.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/10/2007 10:08 PM
I assume you're referring to the reference to an 'optional vehicle upgrade' for use on future LOR-LOR mission profiles from page 10?

As the numbering designations would indicate, it is a four engined Core variant which could be constructed in the future if additional performance were ever required by NASA.   It is more powerful than the 232 but is NOT backward compatible to the 120, so it becomes a separate stand-alone design.   For achieving the current Lunar architecture payload requirements, however, the 232 is more than adequate, and can be used in 120 configuration to support safe, cost-effective manned operations in the near-term. Because of these reasons, the specific details of the 242 variant are really beyond the scope of this particular document.

What we have here are the two, least costly and safest variants - using the exact same Common Core for both - which accomplish all of the criteria set out in the original ESAS analysis.   The Jupiter-120 and the Jupiter-232 can match Ares-I/V's performance and offer a very easy method to actually improve noticeably upon them.   The 242 variant thus becomes an 'option' which can remain on the shelf for the future.

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/10/2007 10:41 PM
Quote
RedSky - 10/5/2007  5:02 PM

To all involved in Direct 2... looks great.  But just a suggestion based on the intended audience: switch to American English spelling rather than UK English (e.g., maneuver for manoeuvre, etc.).  ;)

Thanks.   Good suggestion.   That was my error - I still have my UK English dictionary set up :)

Fixed now.

Ross.
Title: Re: DIRECT v2.0
Post by: Marsman on 05/10/2007 10:44 PM

Congratulations on all of you hard work. I can appreciate all of the intense time and effort spent on the proposal. I stand in awe of your persistence and determination. Fantastic job! A minor question: How does the Jupiter 232 equal or beat the Ares V in LSAM mass with a less powerful launcher?

Title: Re: DIRECT v2.0
Post by: Celeritas on 05/10/2007 11:21 PM
If all of the above numbers are correct then DIRECT makes too much sense.  Hopefully not too much sense for NASA.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/10/2007 11:28 PM
Marsman,
The 232 doesn't beat Ares-V in raw performance - but the 232 is still the *first* rocket - which is equivalent to Ares-I from a cost and schedule perspective.   If the 232 isn't powerful enough, there is no reason why NASA can not make the Ares-V to go with the Jupiter, and still not spend any more than they would for the Ares-I & Ares-V combo.

But if NASA's current budget is any indication, we may never be getting the Ares-V.   Which would you rather be 'stuck' with?   Ares-I or Jupiter?

The Jupiter approach protects against that eventuality.

Ross.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/10/2007 11:31 PM
I wish you guys the best of luck with this.  Its obvious that a ton of work & passion went into this.   It going to be next to impossible to get the NASA managers to just up & change their plans over night.   Your work will have at least put the Direct launch system in position to be the alternative if Ares becomes unworkable due to major problems or a cutback in funds.
Title: Re: DIRECT v2.0
Post by: Marsman on 05/10/2007 11:51 PM

Quote
kraisee - 10/5/2007 7:28 PM Marsman, The 232 doesn't beat Ares-V in raw performance - but the 232 is still the *first* rocket - which is equivalent to Ares-I from a cost and schedule perspective. If the 232 isn't powerful enough, there is no reason why NASA can not make the Ares-V to go with the Jupiter, and still not spend any more than they would for the Ares-I & Ares-V combo. But if NASA's current budget is any indication, we may never be getting the Ares-V. Which would you rather be 'stuck' with? Ares-I or Jupiter? The Jupiter approach protects against that eventuality. Ross.

Sorry for the poor phrasing, my question was that although the Jupiter 232 has less overall performance to LEO, how can it still put a 38-45mt LSAM on the Moon?

The easy part is over. Now you have to deal with the discussions ;)

Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/11/2007 12:53 AM
Regarding the FAQ.  I think an obvious question would be something like, "were these configurations evaluated by NASA?"  If so, the next obvious question would be, "why weren't they selected?"  If not, the next question would be, "how are these configurations different from what was evaluated, and why are they better than those?".  You've already given plenty of why they are better than what was selected (from your point of view, of course).

Best of luck.

Lee Jay
Title: Re: DIRECT v2.0
Post by: Jon_Jones on 05/11/2007 01:41 AM
What would it be like If the LSAM Ascent Stage was Launched with the Orion/Jupiter stack instead of the LASM Descent Stage on the second direct launch? I assume, since Jupiter would be able to get more than just Orion to a stable orbit, that  it could get orion and a lunar suface ascent stage there? Being in a stable orbit, Orion would then have the option of doing the classic Apollo/Saturn flip around to pull the LM off of the SIVB. Of course that would depend which way you want to leave earth orbit. I see that as being the main thing against an idea such as that. Perhaps if you used two Jupiter EDS stages, one on each launch. If it's not impossible, would that free up mass on the LSAM for a larger LSAM and therefore more equipment and/or more habitation. Just a thought.

Perhaps then tht would also allow a larger version of Orion. I personally would like to see a larger capsule for four astronauts. but th'ed probably only be in there for 7 days at the most. However, they would be spending a considerable larger portion of the mission on the surface.

Though, it occurs to me that a larger orion in LEO is a larger target for space debris, but that's true anywhere -pertaining to micromeorites.
Title: RE: DIRECT v2.0
Post by: edkyle99 on 05/11/2007 02:39 AM
Why "Jupiter"?  This name is associated with a short-lived U.S. nuke warhead ballistic missile system.  Why give it a name at all?

- Ed Kyle
Title: RE: DIRECT v2.0
Post by: Ankle-bone12 on 05/11/2007 02:57 AM
Im not a rocket scientist, in fact far from it, but I would assume that it could have something to do with the publics appeal to the flashy name of "Jupiter". It could also be viewed as a "next step up" from the Saturn family of rockets.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/11/2007 03:21 AM
I won't be around tomorrow to field questions, but let me have a stab at these ones so far...

Marsman: The 232 can place a 38mT LSAM into LEO immediately and perform a routine EOR-LOR mission in precisely the same fashion as Ares-I/V.

However, with 45mT of lift capability, the CLV flight has a 'spare' 23mT of performance available on top of lifting the Orion to orbit.   This extra capacity is not initially required, but as the program evolves and confidence is built with the equipment, it could be utilised to increase performance later for almost no additional cost.

Extra payload can theoretically be transferred to the LSAM during the 3 day voyage between the Earth and the Moon.   The most logical material to transfer would be a single type of propellant or oxidixer.   Note: For safety only one or the other should be transferred, not both.

This general technique also applied to the 232/232 LOR-LOR mission profile available later too.   The first 232 is capable of launching a 48mT, partially fuelled LSAM to Lunar Orbit.   The second brings the 22mT Orion and 28mT of extra propellant to the LSAM.   The propellant is transferred to the LSAM prior to descent, and suddenly you have a 76mT LSAM in Lunar orbit and you're still only using a 2-launch strategy based on one single launch vehicle design.

Lee Jay - A variant of the LV-24/25 vehicle from ESAS, but with 2x RS-68's instead of 3x SSME's was considered, but has lower performance than the SSME version.   It never made it into the document because the LV-24/25 pair offered higher performance.   Neither the LV-24/25 nor the RS-68 variant was fully evaluated with an EDS flying on one flight though.   ESAS missed this option, but the LV-24/25 performance does show the "potential" by demonstrating the basic LV without EDS has a lot of performance available.

Jon Jones: You want to keep Orion's mass as low as possible still.   Always the minimum for the requirements when you're dealing with sensitive hardware on a mass budget for a lunar mission.   Every pound of material it uses in its struture is a pound of material you can't use elsewhere, like for propellant and useful cargo (people, experiments).   I understand that the current Orion is going to be quite "roomy" compared to Apollo, not to mention that the accompanying LSAM Ascent Module will also be fairly spacious.   A four man crew should be acceptably comfortable with the current configurations as is.   Just for the record, the CEV's mass is second only to the mass of the LSAM on the "critical" scale.   The CEV has to go all the way to the moon and back again.   Only the LSAM has to go down into the gravity well of the moon to the lunar surface though - so reducing mass on the LSAM is even more critical than on the CEV.

Orbital Propellant Transfer is a far less precarious option than attempting to integrate an LSAM Ascent Stage to a Descent Stage in orbit.   To make use of extra carrying capacity, this is probably the better alternative and allows NASA to integrate & checkout the LSAM completely on the ground before ever committing to a mission.

edkyle99The name was selected because we combined our DIRECT efforts with some of the members of the Team Vision proposal a while back.   DIRECT saw a lot of value in their Jupiter-1 concept, which was surprisingly similar to DIRECT in concept and execution.

I will let Steve comment on why Team Vision chose that name, but for me it represents the larger brother world to Saturn.   Our standard launch vehicles are designed to fly mostly in pairs to accomplish all mission objectives, and together they offer 262mT launch capability per pair .   262mT is almost double the performance of a single mighty Saturn-V, so seems a fitting name for a successor.

Also, in Roman mythology, Jupiter was the guardian and protector of all the other Gods.   We believe Jupiter will "protect" NASA from the worst of budgetary storms and "guard" our tax investment for the next three decades far better than other options.

And finally, Jupiter planetary systems, the Jovian system is the etmylogical root of the term "jovial" - which represents happiness.   We hope Jupiter will get a chance to make everyone happy ultimately.

Ross.
Title: RE: DIRECT v2.0
Post by: RedSky on 05/11/2007 03:35 AM
Quote
Ankle-bone12 - 10/5/2007  9:57 PM
Im not a rocket scientist, in fact far from it, but I would assume that it could have something to do with the publics appeal to the flashy name of "Jupiter". It could also be viewed as a "next step up" from the Saturn family of rockets.

I don't think you have to be a rocket scientist to name a rocket.  ;)  
Besides being an ICBM, a version called the Jupiter C was the rocket that launched the US's first satellite, Explorer I.  I think that model developed into the similar Redstone, that launched the first two manned Mercury suborbital flights.  Then 8 Redstone tanks were planned to be clustered around a Jupiter core.  They needed a name for the new advanced rocket, so the next planet out from Jupiter was Saturn, and that name stuck (it became the Saturn I).  Don't know how true that story is, but it sounds plausible. Of course, following that example the next step beyond Saturn would be... oh, never mind.  :laugh:
Title: Re: DIRECT v2.0
Post by: CFE on 05/11/2007 04:14 AM
Quote
kraisee - 10/5/2007  9:21 PM
And finally, Jupiter planetary systems, the Jovian system is the etmylogical root of the term "jovial" - which represents happiness.   We how Jupiter will get a chance to make everyone happy ultimately.

You can bet that Griffin, Stanley & Horowitz aren't too jovial right about now.  Too many "independent thought alarms" going off at NASA headquarters for the management to be happy.
Title: RE: DIRECT v2.0
Post by: edkyle99 on 05/11/2007 04:27 AM
Quote
RedSky - 10/5/2007  10:35 PM

Quote
Ankle-bone12 - 10/5/2007  9:57 PM
Im not a rocket scientist, in fact far from it, but I would assume that it could have something to do with the publics appeal to the flashy name of "Jupiter". It could also be viewed as a "next step up" from the Saturn family of rockets.

I don't think you have to be a rocket scientist to name a rocket.  ;)  

I'm suppose I'm just tired of the overused Greek and Roman naming conventions for rockets and missiles.  How about something original and different?  Weather phenomena ("Hurricane", "Thunder", etc)?, or a river ("Hudson", "Cumberland", "Potomac", etc),  or a bird ("Falcon", "Egret", "Kingfisher", etc.), or a beloved cartoon science fiction dog ("Astro"), etc.?  Or call it "Constellation Launch Vehicle", "Constellation" for short.

 - Ed Kyle

Title: RE: DIRECT v2.0
Post by: Alpha Control on 05/11/2007 04:36 AM
You know, I didn't find out the correct pronunciation of the 6th planet for many years.  In the original Greek, it is UR-an-us, with the accent on the 1st syllable. Uranus was one of the original gods, prior to the Olympian gods.

When I was growing up, the accent was always on the 2nd syllable, which of course provided endless mirth for school age boys.

But back to the naming scheme, since Ares represents Mars, you could say that Jupiter, being the next planet, would therefore be a step up.

David
Title: Re: DIRECT v2.0
Post by: bad_astra on 05/11/2007 05:12 AM
Let NASA call it Ares 1b for all I care. This is tremendous work. I hope some politicians can get a look at this.
Title: Re: DIRECT v2.0
Post by: CFE on 05/11/2007 06:46 AM
Regarding the issues of tank diameter and propellant load, I have to ask: are the tanks being milled thicker on the inner surface, as opposed to the outer surface? It seems to me that doing so (reducing the inner diameter) would lead to a small (but considerable) decrease in your propellant volume compared to the baseline ET.  OTOH, if the inner diameter was kept constant and the outer skins were beefed up, it would force changes to the SRB attach struts in order to keep the pad footprint the same.
Title: Re: DIRECT v2.0
Post by: JIS on 05/11/2007 10:07 AM
If I understand that correctly you are requiring to scrap current Orion SM proposal.
For EOR-LOR DIRECT architecture Orion has to perform LOI.
For LOR-LOR DIRECT architecture Orion has the same weight as LSAM. Therefore, some propellants transfer between them will be required.
Also still mysterious is the Direct EDS which has the same dry weight as ESAS original EDS (with 2xJ2S+) but 40% more propellants.
Title: Re: DIRECT v2.0
Post by: JIS on 05/11/2007 10:34 AM
Quote
kraisee - 11/5/2007  4:21 AM

I won't be around tomorrow to field questions, but let me have a stab at these ones so far...

Marsman: The 232 can place a 38mT LSAM into LEO immediately and perform a routine EOR-LOR mission in precisely the same fashion as Ares-I/V.

However, with 45mT of lift capability, the CLV flight has a 'spare' 23mT of performance available on top of lifting the Orion to orbit.   This extra capacity is not initially required, but as the program evolves and confidence is built with the equipment, it could be utilised to increase performance later for almost no additional cost.

Unfortunatelly the extra integration costs are not negligible. See current EELV launches.

Quote
Extra payload can theoretically be transferred to the LSAM during the 3 day voyage between the Earth and the Moon.   The most logical material to transfer would be a single type of propellant or oxidixer.   Note: For safety only one or the other should be transferred, not both.

From where?

Quote
This general technique also applied to the 232/232 LOR-LOR mission profile available later too.   The first 232 is capable of launching a 48mT, partially fuelled LSAM to Lunar Orbit.   The second brings the 22mT Orion and 28mT of extra propellant to the LSAM.   The propellant is transferred to the LSAM prior to descent, and suddenly you have a 76mT LSAM in Lunar orbit and you're still only using a 2-launch strategy based on one single launch vehicle design.

Again, you are not serious. This is just quick armchair idea which has nothing together with the mission architecture.
The second DIRECT launch brings 22mT Orion and 28mT extra popellant in a second new spaceship wighting 0mT?
Even if the first Direct is able to get 48mT LSAM to LLO and the second Direct 22mT Orion and 28mT(sic) second new spaceship to the LLO (that's 50mT together) I still can't see any 76mT LSAM.
Certainly not 76mT LSAM which could work.




Title: Re: DIRECT v2.0
Post by: JIS on 05/11/2007 10:51 AM
What is the performance margin for the new components (EDS, Core, shrouds)?
Title: Re: DIRECT v2.0
Post by: JIS on 05/11/2007 01:00 PM
Are those 3 RS-68 inline ... or in star :. arrangement?
If it is the star one there will be somewhat higher bending moment for the two engine core than for Ares 1 / Ares 5 config. Could the recent Orion with LSAM stand this lateral load?
If it is an inline config can 3 engine nozzles fit under the 27.5' core? Ofcourse, there could be some aerodynamic (debris) shield above them with wider and loger thrust structure.
Title: Re: DIRECT v2.0
Post by: Jim on 05/11/2007 01:06 PM
There isn't a lateral load for a .: 3 engine configuration.  It is symmetrical
Title: Re: DIRECT v2.0
Post by: clongton on 05/11/2007 01:09 PM

Quote
JIS - 11/5/2007 9:00 AM

Are those 3 RS-68 inline ... or in star :. arrangement?
If it is the star one there will be somewhat higher bending moment for the two engine core than for Ares 1 / Ares 5 config. Could the recent Orion with LSAM stand this lateral load?
If it is an inline config can 3 engine nozzles fit under the 27.5' core? Ofcourse, there could be some aerodynamic (debris) shield above them with wider and loger thrust structure.
3-Engine is in-line with aerodynamic skirts, like Saturn-V
Outboard engines gimbal, center engine fixed, again, like Saturn-V

"3-Engine

Title: Re: DIRECT v2.0
Post by: JIS on 05/11/2007 01:17 PM
Quote
Jim - 11/5/2007  2:06 PM

There isn't a lateral load for a .: 3 engine configuration.  It is symmetrical
But there is also Direct with only two engines. Anyway, its inline config.
Title: Re: DIRECT v2.0
Post by: rumble on 05/11/2007 01:24 PM
Quote
JIS - 11/5/2007  8:17 AM

Quote
Jim - 11/5/2007  2:06 PM

There isn't a lateral load for a .: 3 engine configuration.  It is symmetrical
But there is also Direct with only two engines. Anyway, its inline config.
Right.  Like Chuck said, the 3-engine Jupiter has 3 inline engines with skirts around the outer two.  The 2-engine variant IS the 3-engine variant with the center engine removed and its feed lines plugged.

DIRECT team:  Nice presentation of some good detailed work.  Kudos.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/11/2007 01:32 PM
Quote
JIS - 11/5/2007  6:07 AM

If I understand that correctly you are requiring to scrap current Orion SM proposal.

Of course not.   That would be wasteful.

For the first generation, we can use whatever variant was planned to fly on Ares-I, although because Jupiter is far less sensitive to "growth" of a payload than Ares-I, at this stage they can now afford to steer away from highly expensive "exotic" solutions in favour of cheaper, slightly heavier items.   This will help to reduce the costs of the spacecraft manufacturing noticeably.

We can actually reduce the size of the MMH/N2O2 tanking in the Block I and Block II versions - because the CEV is no longer required to complete the ascent to LEO - Jupiter handles all that except the final circularization burn.   That means the CEV can carry 4 tons less propellant at liftoff than at present.

We need a little of that back (I don't have the current figure in front of me, but it's about 1.2 tons IIRC) for the LOI burn, but we have an overall mass benefit in the region of 2.8mT less propellant on every spacecraft.


For later missions, a Block III Service Module would include extra tanking for the LSAM's propellant.   That would be for around 2020, so is still quite a ways off.   In the interim trades would need to be done to figure out which propellant would be best to transfer.   If the SM and AS both use the same propellant, then MMH or N2O2 might be a fair choice.   Or perhaps 20+ tons of LOX would be better for the DS.   The only way we're going to know optimal performance is by examining suitable trade studies - and that would be NASA's purview over the next decade.

And there's nothing mysterious about our EDS.   For a start it does not "weight the same" as ESAS'.   It weighs about 2,200lb more, which is about 5% more.   It also doesn't use the same manufacturing approach.   Anyone can go read the AIAA papers into the ICES stage and you'll learn how it is noticably more efficient than the stage NASA designed for the ESAS CaLV.

ESAS used a methodology which assumed separate tanking, and old technologies for boiloff control.   ICES saves mass instantly by using a common bulkhead (which NASA learned was the way to go on the US for Ares-I too) and uses a number of new technology elements for boiloff control which are lighter in construction than ESAS ever planned.   A *LOT* has been learned from Centaur over the years, and ICES is the result.

Ross.
Title: Re: DIRECT v2.0
Post by: Jim on 05/11/2007 01:32 PM
Just a little encouragement for the Direct team.  Think of Direct 2.0 as your mulligan (golfers know what I am talking about).  Just as the Stick was non-viable (4 segments with SSME) in the beginning and it went through a "redesign".  So as a counter to the SSS website trashing Direct, just point out that Stick 1.0 wouldn't work either.
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/11/2007 01:34 PM
Quote
clongton - 11/5/2007  9:09 AM

Quote
JIS - 11/5/2007 9:00 AM

Are those 3 RS-68 inline ... or in star :. arrangement?
If it is the star one there will be somewhat higher bending moment for the two engine core than for Ares 1 / Ares 5 config. Could the recent Orion with LSAM stand this lateral load?
If it is an inline config can 3 engine nozzles fit under the 27.5' core? Ofcourse, there could be some aerodynamic (debris) shield above them with wider and loger thrust structure.
3-Engine is in-line with aerodynamic skirts, like Saturn-V
Outboard engines gimbal, center engine fixed, again, like Saturn-V

"3-Engine


3 engines inline is also the Kistler's K1 config. BTW I love the D2 presentation.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/11/2007 01:42 PM
Quote
JIS - 11/5/2007  6:51 AM

What is the performance margin for the new components (EDS, Core, shrouds)?

All ESAS GRA's and margins were matched initially, and then, as always with DIRECT analysis, we have added a further 2% margin on top of those, to give us even more margin.

Additionally, we are ***not*** utilizing the NASA Ares-V specification RS-68 (414.2s vac Isp), we are retaining the current 409s Isp performance variant, so we have additional and very realistic upgrades available to all performance numbers if/when required.   Not to mention the Delta-IV Regen engine with 418s Isp which is coming too (although is likely to be rather costly, so isn't so useful).

Nor are we using the higher specification J-2X with 293,000lb, 448s vac Isp, we are sticking with the lower spec, lower cost, and easier to achieve specification of the initial J-2X"D" variant with just 273,500lb, 448s performance.

These are two, very straight-forward and highly achievable upgrade paths available to us in the future, which would increase performance of the smaller vehicle to around 52mT to LEO, and of the larger to around 115mT, but we are not relying upon even those for this proposal.

We have more margin than either CLV or CaLV had originally, and have additional performance alternatives available almost immediately - which is something neither Ares-I nor Ares-V have.

Title: Re: DIRECT v2.0
Post by: kraisee on 05/11/2007 01:50 PM
Just to clarify, the engines are mounted in-line to keep maximum distance between them and the SRB's.

While Chuck is correct that the center engine will not (probably) gimbal, it will actually still be an identical unit produced on the same production line as all the rest, only being a central engine, and will have the hardware allowing gimbal control, it simply isn't likely to be instructed to gimbal because the outboard engine pair offer greater control authority.

As you point out, the interchangeable common cores can also be flown without the central engine in the smaller 120 configuration.   The two outboard engines remain exactly where they are in either configuration.   The electrical & plumbing connections to the central engine will simply be capped & closed out that way for such flights.

Ross.
Title: Re: DIRECT v2.0
Post by: clongton on 05/11/2007 02:01 PM
After examining the move and shock envelope around each engine, allowing for the full range of gimbal motion, plus margin, and addressing the design of an appropriate thrust structure, the distance between the two outboard engines, center to center, is approximately the same as NASA currently baselines for the Ares-V outboard engines. In addition, the engine skirt design used these same design parameters and closely resembles the engine skirts around the Saturn-V F1 engines.
Title: Re: DIRECT v2.0
Post by: kevin-rf on 05/11/2007 02:10 PM
So Chris, any chance of getting Dr. Doug Stanley back to comment on Direct 2.0?

Good job Ross...
Title: Re: DIRECT v2.0
Post by: Jon_Jones on 05/11/2007 02:17 PM
Thanks very much Ross for your considerate reply.
Title: Re: DIRECT v2.0
Post by: Chris Bergin on 05/11/2007 03:13 PM
Quote
kevin-rf - 11/5/2007  3:10 PM

So Chris, any chance of getting Dr. Doug Stanley back to comment on Direct 2.0?


Dr Stanley's a busy man, so it'd all depend on his time and his willingness.

Although, probably not, if it results in an ATK site - run by what appears to be a bunch of monkeys - then using his comments without correct sourcing, context or objectivity in some attempt to have a Stick group hug. However, I am encouraged to see that they've worked out how to copy and paste over there in ATK web propaganda HQ. ;)
Title: Re: DIRECT v2.0
Post by: jongoff on 05/11/2007 03:17 PM
Quote
CFE - 10/5/2007  11:46 PM

Regarding the issues of tank diameter and propellant load, I have to ask: are the tanks being milled thicker on the inner surface, as opposed to the outer surface? It seems to me that doing so (reducing the inner diameter) would lead to a small (but considerable) decrease in your propellant volume compared to the baseline ET.  OTOH, if the inner diameter was kept constant and the outer skins were beefed up, it would force changes to the SRB attach struts in order to keep the pad footprint the same.

CFE, the difference is actually negligible when taken as a percentage of total tankage volume.  We're talking about a tank that is quite big.  Basically, for every extra cm of thickness, you're losing 0.2% of propellant....and I don't think you need even a cm of extra material to take the loads.  It's an effect, but it's pretty much roundoff error.

~Jon
Title: Re: DIRECT v2.0
Post by: Flightstar on 05/11/2007 03:34 PM
Good work on the presentation. Sure would help pad integration problems.
Title: Re: DIRECT v2.0
Post by: Steve G on 05/11/2007 03:42 PM
If NASA did select Direct, and had a fresh look at the VSE, what would be the benefits and disadvantages of having a dual lunar launch scenario where the LSAM would be launched to a high lunar orbit storage orbit, and Orion launched separately.  Orion would use a larger (Apollo-type) SM engine and then take the LSAM to it’s final orbit, preserving weight on the lander.

Since weight would no longer be a constraint to Orion, and we’ve just saved $30 billion, a mission module could be added making it a more comfortable flight, a small lab for lunar orbit studies, and a full 6 crew could be launched, with two remaining aboard the Orion (safer than an unmanned version) and conduct in orbit studies and in a better position to react to a major malfunction on either spacecraft.

One obvious advantage would also be the launch window.  If the Orion launch had a major last minute delay after the LSAM reached earth orbit, there wouldn’t be a propellant boil off issue and lose the entire mission.  LSAM could be stored in lunar orbit indefinitely.
Title: Re: DIRECT v2.0
Post by: Jim on 05/11/2007 04:07 PM
Don't start will mission modules.  They aren't needed and cloud the advantages of the proposal.  Room is not needed.  Use the excess capability to put instruments on the CEV, just as Apollo but unlike Apollo, it need not be manned

there still would be boiloff issues unless the LSAM went with storable propellants and in that case, its mass would greatly increase
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/11/2007 04:10 PM
Quote
kraisee - 11/5/2007  9:50 AM

Just to clarify, the engines are mounted in-line to keep maximum distance between them and the SRB's.

While Chuck is correct that the center engine will not (probably) gimbal, it will actually still be an identical unit produced on the same production line as all the rest, only being a central engine, and will have the hardware allowing gimbal control, it simply isn't likely to be instructed to gimbal because the outboard engine pair offer greater control authority.

As you point out, the interchangeable common cores can also be flown without the central engine in the smaller 120 configuration.   The two outboard engines remain exactly where they are in either configuration.   The electrical & plumbing connections to the central engine will simply be capped & closed out that way for such flights.

Ross.

A center engine has nearly the same control authority as the side engines for pitch and yaw. So, it adds you a nice extra margin if you want it, at the expense of having to develop two control algorithms for 2 vs. 3 engines. Actually scratch that, that's a negligible expense. You're better off by getting rid of all the gimbaling support, saving that weight.
Title: Re: DIRECT v2.0
Post by: clongton on 05/11/2007 04:20 PM
Quote
GncDude - 11/5/2007  12:10 PM

Quote
kraisee - 11/5/2007  9:50 AM

Just to clarify, the engines are mounted in-line to keep maximum distance between them and the SRB's.

While Chuck is correct that the center engine will not (probably) gimbal, it will actually still be an identical unit produced on the same production line as all the rest, only being a central engine, and will have the hardware allowing gimbal control, it simply isn't likely to be instructed to gimbal because the outboard engine pair offer greater control authority.

As you point out, the interchangeable common cores can also be flown without the central engine in the smaller 120 configuration.   The two outboard engines remain exactly where they are in either configuration.   The electrical & plumbing connections to the central engine will simply be capped & closed out that way for such flights.

Ross.

A center engine has nearly the same control authority as the side engines for pitch and yaw. So, it adds you a nice extra margin if you want it, at the expense of having to develop two control algorithms for 2 vs. 3 engines. Actually scratch that, that's a negligible expense. You're better off by getting rid of all the gimbaling support, saving that weight.
From the point of view of commonality and interchangeability, we are better off leaving all three engines as identical. That makes everything easier. This launch vehicle has more than enough margin to allow the design to be simplified by commonality. That’s the beauty of fielding a launch vehicle that starts life with lots of margin vs. starting life already maxed out.
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/11/2007 05:12 PM
Quote
clongton - 11/5/2007  12:20 PM

Quote
GncDude - 11/5/2007  12:10 PM

A center engine has nearly the same control authority as the side engines for pitch and yaw. So, it adds you a nice extra margin if you want it, at the expense of having to develop two control algorithms for 2 vs. 3 engines. Actually scratch that, that's a negligible expense. You're better off by getting rid of all the gimbaling support, saving that weight.
From the point of view of commonality and interchangeability, we are better off leaving all three engines as identical. That makes everything easier. This launch vehicle has more than enough margin to allow the design to be simplified by commonality. That’s the beauty of fielding a launch vehicle that starts life with lots of margin vs. starting life already maxed out.

In that case you may as well gimbal it.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/11/2007 05:27 PM
That just makes it more complicated, more things to fail.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/11/2007 05:33 PM
Wouldn't you want to gimbal the center engine in a side engine-out situation?
Title: Re: DIRECT v2.0
Post by: Carl G on 05/11/2007 05:34 PM
On Direct 1, some people said it is a hybred of an MSFC concept. If this is true, what stops the MSFC version? Money, wrong time, showstoppers?
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/11/2007 06:23 PM
Quote
veedriver22 - 11/5/2007  1:27 PM

That just makes it more complicated, more things to fail.

Not really. If you are going to have all the mechanisms there and active (for commonality), the fact that you're moving them around versus not moving them adds minimal complexity, and buys you control margin.
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/11/2007 06:26 PM
Quote
Lee Jay - 11/5/2007  1:33 PM

Wouldn't you want to gimbal the center engine in a side engine-out situation?

Yes, but I think if this happens in DIRECT you lose the mission anyway. Right? I don't know if the 232's have engine out capability. Haven't looked.
Title: RE: DIRECT v2.0
Post by: Smatcha on 05/11/2007 06:28 PM
Quote
Ankle-bone12 - 10/5/2007  7:57 PM

Im not a rocket scientist, in fact far from it, but I would assume that it could have something to do with the publics appeal to the flashy name of "Jupiter". It could also be viewed as a "next step up" from the Saturn family of rockets.

Why Jupiter?  First off if we used Ares in some other form it would confuse everyone.

Second, when I asked a number of non space enthusiast’s individuals about the prior lunar mission many of them knew that the rocket was the Saturn V.

When I asked them which planet was the largest in the solar system they said Jupiter.

So I felt that not only did the Jupiter embody a connection to the first Lunar program but also indicated doing more in this next phase.  The Jupiter-2 can put more in orbit than the Saturn V.

Next the name Jupiter.  Jupiter son is Mars.  NASA has attempted to make a sideways relation to Zeus son being Ares but nobody I talked to (outside of us space geeks) knew what I was talking about unlike the Saturn-Jupiter connection.

I also like the whole 2001 and 2010 a Space Odyssey connection with Jupiter.  The name also implies other missions beyond Mars indicating the whole “beyond” part of VSE.

Back to other legacy associations:

The name the Hindus gave the planet Jupiter was Guru or “knowledge seeker” a very good association.

In Romans mythology Jupiter was the ruler of the gods, and their guardian and protector.

In astrology Jupiter is associated with growth, expansion, higher education, prosperity, and protecting roles.   All very positive associations.  If we ever have an asteroid with our name on it the protecting role would also be most appropriate.

Onto Ares, he was the son of Zeus (the Greek king of the gods).  He is not so much the god of war but more accurately the god of savage or unnecessary war.  Associations which I think take a back seat to Jupiter in all ways.

Though savage and unnecessary certainly would describe the last two years to a tee so maybe Ares is good name after all for this point in time.
Title: Re: DIRECT v2.0
Post by: clongton on 05/11/2007 06:33 PM
Quote
GncDude - 11/5/2007  2:26 PM

Quote
Lee Jay - 11/5/2007  1:33 PM

Wouldn't you want to gimbal the center engine in a side engine-out situation?

Yes, but I think if this happens in DIRECT you lose the mission anyway. Right? I don't know if the 232's have engine out capability. Haven't looked.
The 232 does have engine-out capability, though not to the extent of the 120
Title: Re: DIRECT v2.0
Post by: zinfab on 05/11/2007 06:50 PM
Thanks for this update. I hope someone listens when it REALLY counts.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/11/2007 07:03 PM
Quote
zinfab - 11/5/2007  1:50 PM

Thanks for this update. I hope someone listens when it REALLY counts.

I think the Democrats will listen and if they win the Presidency they will probably install an Administrator to drop Ares I/V for DIRECT as it will allow them to beef up Science in Nasa whilst still keeping VSE going well even on a flat budget. I have reluctantly come round to Jim's way of thinking in believing that Griffin and Horowitz are so in bed with ATK they will persist with the current architecture come what may and they probably will return there to collect their rewards in 2008. This DIRECT proposal should be continued regardless to shine a light on the current architecture's failings for possible use when a different NASA power base is established.
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/11/2007 07:19 PM
Quote
marsavian - 11/5/2007  12:03 PM

Quote
zinfab - 11/5/2007  1:50 PM

Thanks for this update. I hope someone listens when it REALLY counts.

I think the Democrats will listen and if they win the Presidency they will probably install an Administrator to drop Ares I/V for DIRECT as it will allow them to beef up Science in Nasa whilst still keeping VSE going well even on a flat budget. I have reluctantly come round to Jim's way of thinking in believing that Griffin and Horowitz are so in bed with ATK they will persist with the current architecture come what may and they probably will return there to collect their rewards in 2008. This DIRECT proposal should be continued regardless to shine a light on the current architecture's failings for possible use when a different NASA power base is established.

ATK actual benefits more with DIRECT.  So Mike and Scott can still do the right thing and get rewarded for it all at the same time.  

Now how often does that happen? :)

Once again it’s better to lucky than smart.



Title: Re: DIRECT v2.0
Post by: marsavian on 05/11/2007 07:21 PM
I think ATK want Ares I so they can use it commercially vs EELVs, that's the real reason I believe.
Title: Re: DIRECT v2.0
Post by: clongton on 05/11/2007 07:34 PM
Quote
marsavian - 11/5/2007  3:21 PM

I think ATK want Ares I so they can use it commercially vs EELVs, that's the real reason I believe.
The DIRECT Launch manifest on page 4 of the proposal shows (26) 4-segment flights between 2009 and 2017. That’s 8 years. How many Ares-1 flights (5-segment) will there be in that same time period? Anybody know? This is assuming of course, that Jupiter gets the same funding as Ares would have.

Let’s see:
26 Flights x 2 SRB’s each = 54 SRB’s
54 SRB’s x 4 segments each = 208 segments for ATK to refurbish and repack.

Vs. how many 5-segment SRB’s for Ares-1 in the same timeframe?
How much does ATK get paid for each refurbished 4-segment SRB? Does anybody know?

Bottom line – ATK makes one hell of a lot more money with the Jupiter than it does with the Ares-1, or even if they were to compete against Atlas and Delta. And, if the Falcon becomes viable, what percentage of the market could they realistically expect? Somebody needs to seriously re-teach the execs at ATK just what “bottom line” means to the shareholders.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/11/2007 07:42 PM
Heh,  perhaps  ;)
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/11/2007 07:42 PM
Quote
marsavian - 11/5/2007  12:21 PM

I think ATK want Ares I so they can use it commercially vs EELVs, that's the real reason I believe.

So instead of have two US based companies losing money we can have three?  Good idea ATK we'll lose money on each launch but make it up in the volume :)

If anything given the current launch volume we should be looking at some kind-of Cost plus contract consolidation or hybrid ELV.  Ideally coordinated with the DIRECT.

Title: Re: DIRECT v2.0
Post by: zinfab on 05/11/2007 08:27 PM
Quote
clongton - 11/5/2007  3:34 PM

Quote
marsavian - 11/5/2007  3:21 PM

I think ATK want Ares I so they can use it commercially vs EELVs, that's the real reason I believe.
The DIRECT Launch manifest on page 4 of the proposal shows (26) 4-segment flights between 2009 and 2017. That’s 8 years. How many Ares-1 flights (5-segment) will there be in that same time period? That assumes Jupiter gets the same funding as Ares would have.

Let’s see:
26 Flights x 2 SRB’s each = 54 SRB’s
54 SRB’s x 4 segments each = 208 segments for ATK to refurbish and repack.

Vs. how many 5-segment SRB’s for Ares-1 in the same timeframe?
How much does ATK get paid for each refurbished 4-segment SRB? Does anybody know?

Bottom line – ATK makes one hell of a lot more money with the Jupiter than it does with the Ares-1, or even if they were to compete against Atlas and Delta. And, if the Falcon becomes viable, what percentage of the market could they realistically expect? Somebody needs to seriously re-teach the execs at ATK just what “bottom line” means to the shareholders.


That reminds me of the objection lawmakers had about "tax free space" proposals. If there's no one flying, there's no tax to be "lost." In the end, we get the worst of both worlds -- fear of losing taxes that wouldn't be there if you're charging tax.
Title: Re: DIRECT v2.0
Post by: Pete at Edwards on 05/11/2007 10:53 PM
Good effort guys.
Title: Re: DIRECT v2.0
Post by: on 05/12/2007 05:35 AM
My favorite of DIRECT 2.0 is the introduction page - it doesn't oversell, it addresses the basic objectives crisply. Any on the committee can "get it". The staffers read the rest and use it to advise for the "oversight" role. Sometimes its possible to "overdo a good thing" and miss the point.

Kudos to the DIRECT team - they didn't overreach, they worked to the correct goal. A very professional job.
Title: Re: DIRECT v2.0
Post by: gladiator1332 on 05/12/2007 05:28 PM
Quote
marsavian - 11/5/2007  3:03 PM

Quote
zinfab - 11/5/2007  1:50 PM

Thanks for this update. I hope someone listens when it REALLY counts.

I think the Democrats will listen and if they win the Presidency they will probably install an Administrator to drop Ares I/V for DIRECT as it will allow them to beef up Science in Nasa whilst still keeping VSE going well even on a flat budget. I have reluctantly come round to Jim's way of thinking in believing that Griffin and Horowitz are so in bed with ATK they will persist with the current architecture come what may and they probably will return there to collect their rewards in 2008. This DIRECT proposal should be continued regardless to shine a light on the current architecture's failings for possible use when a different NASA power base is established.

I agree with you 100% on this. Who would have thought we would be saying that the Dems would be the ones to save the VSE

I think Hillary and Obama will hold off on the Moon. They may go for a stripped down VSE where Orion just goes to the ISS on an EELV or on DIRECT (at least this keeps the Moon as a future option)

Richardson has shown support for spaceflight in New Mexico, he has supported the space port and the X-Prize Cup. While he does lean more towards the private sector of spaceflight, I feel he will push COTS along and will support the VSE if it is made cheaper with DIRECT.

Edwards I am unsure of, however, he is more into social programs and helping the poor. I would rope him in with Hillary and Obama, where he will support the Orion to ISS plan, but if DIRECT can make the VSE cheaper, I feel he would be all for this. He seems to be the "Dream Big" candidate, and what better way than to go back to the Moon.

To be on the safe side Hillary must be avoided at all costs if we want to go back to the Moon. Richardson is our best bet. One thing that all of the Dems have in common is that Griffin is toast.
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/12/2007 05:59 PM
Quote
clongton - 11/5/2007  2:33 PM

Quote
GncDude - 11/5/2007  2:26 PM

Quote
Lee Jay - 11/5/2007  1:33 PM

Wouldn't you want to gimbal the center engine in a side engine-out situation?

Yes, but I think if this happens in DIRECT you lose the mission anyway. Right? I don't know if the 232's have engine out capability. Haven't looked.
The 232 does have engine-out capability, though not to the extent of the 120

Awesome. Next time I read before talking. So you want identical engine due to commonality, and you want engine out capability, then you probably want that center engine gimbaling just like the others. I see no point on having it fixed.  Well, in any case these are just details details.
Title: Re: DIRECT v2.0
Post by: bad_astra on 05/12/2007 06:03 PM
The next president will be the one who has the option of being "The president who killed manned spaceflight in America" Congressionally there's to much at risk to do that. The war, energy policy, whatever-pointless-social-leper-buzzword-the-neocons-come-up-with, are going to be the key issues in 2008, and I suspect with modifications, VSE will continue on with little attention, unless we loose another shuttle.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/12/2007 07:35 PM
Flightstar:

Yes, we are well aware of the current Pad issues.   There is likely to be an appendix coming soon which will update the DIRECT v1 pad systems plans to v2 specification.   We are still collecting updated information, and figured it could wait until after this "Core Document" was released.

CFE and Jongoff:

The basic tank wall is only slightly thicker than 1/4" thick - with a milled grid structure inside that.   If the wall thickness were doubled (by milling less from the inside, always keeping the outer mouldline), the effect to capacity is minimal.   This is actually one of the changes performed between the original ET specification, the Light Weight Tank and ultimately the Super Lightweight Tank.   Think of DIRECT as going back to the original tank initially, until the dynamics are examined in real flight conditions and an optimization program can be implemented later for a Block II Core.   Our mass calculations have always assumed this approach.

GncDude:

The center engine will have the hardware to gimbal still.   We aren't specifying flying two different variants of RS-68.   Our plan specifically calls for all MPS units to be interchangeable for maximum flexibility during launch processing.   Our current information indicates the center engine shouldn't need to do any gimballing, but as you say, it offers extra margin.   Also it can obviously be useful in the case of any unexpected engine shutdown conditions.   DIRECT does have engine-out capability after all.

Carl G:

The original MSFC specification called for three SSME's, and didn't have an upper stage.   The SSME's are very expensive for a disposable launcher like this, so aren't ideally suited.   We can use 2 RS-68's and get very similar thrust, and they were always designed to be cheap enough to throw away.   We have also extrapolated the need for an EDS for lunar missions, and the use of it also during ascent to boost lift performance on the ESAS CaLV and later the Ares-V.   It is clearly the right approach, and works very well on this lifter.

Chuck Longton:

208 segments for ATK to refurbish on Jupiter boosters from 2009 thru 2017.   The same time frame on the Ares program will require them to refurbish the following segments:-

4 Ares-I test flights = 20 segments.
2 Ares-I support flights to ISS in 2015 = 10 segments.
2 Ares-I support flights to ISS in 2016 = 10 segments.
1 Ares-I flight to service Hubble (may not be done at all due to no payload being able to fly on the same flight and an EELV cost thus having to be added to the mission costs): = 5 segments.
1 Ares-V test flight - not confirmed yet, but possible no earlier than 2017 or 2018 = 10 segments.

TOTAL (including all 'optional' flights): 55 segments.


NOTE: Neither DIRECT, nor Ares numbers above include any static test firing unit numbers.


Marsavian:

I'm not convinced ATK suffers at all.   ATK make the ablative nozzle for all RS-68's currently, so flying a bunch more of those is certainly in ATK's interests.   Also, ATK's parent company is United Technologies - who also own Pratt & Whitney/Rocketdyne.

All talking about the politics:

I hope Griffin & the other administrators realize that the VSE's budget is going to be at risk long after they are off doing something else.   If they leave Ares-I as the first booster, there is a very real chance NASA will never get its second booster at all.   At that point NASA will have spent billions getting a nice shiny new launcher, but it won't ever be able to go to the moon.

DIRECT's Jupiter as the first booster would cost no more than Ares-I to make and certify, yet offers an instantly capable system which can still get NASA to the moon even if Ares-V went away.

Do NASA's current administration really wish to risk the future moon program on the 12 year long political gamble that Congress will fully fund Ares-V?

I can't see them winning that bet ultimately.

And if NASA loses that bet, Griffin's name will only ever be remembered, very bitterly, as the Administrator who got NASA stuck in LEO again while the Chinese continue their program to reach the moon.

"Faster, better, cheaper"'s legacy reflects incredibly badly today on Dan Goldin - today considered by most as NASA's #1 enemy, rivalling only Sen. Mondale.   Will "Safe, Simple, Soon" be remembered as bitterly by all future American generations?   I believe that Ares-I is the deciding issue which can sway that either way.

I don't think it's too late to change to a plan which removes that gamble entirely, but only if they pull their collective heads out of Ares-I's nozzle.

Ross.
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/12/2007 07:52 PM
Quote
kraisee - 12/5/2007  3:35 PM

Marsavian:

[...] more of those is certainly in ATK's interests.   Also, ATK's parent company is United Technologies - who also own Pratt & Whitney/Rocketdyne.


I don't think ATK is related to UTC.
Title: Re: DIRECT v2.0
Post by: Jim on 05/12/2007 08:15 PM
Quote
GncDude - 12/5/2007  3:52 PM

Quote
kraisee - 12/5/2007  3:35 PM

Marsavian:

[...] more of those is certainly in ATK's interests.   Also, ATK's parent company is United Technologies - who also own Pratt & Whitney/Rocketdyne.


I don't think ATK is related to UTC.

correct
Title: Re: DIRECT v2.0
Post by: CFE on 05/12/2007 08:49 PM
Quote
gladiator1332 - 12/5/2007  11:28 AM
One thing that all of the Dems have in common is that Griffin is toast.

That's for certain.  NASA administrators are political animals, and are rarely retained when the party controlling the White House changes.  The only exceptions were Dan Goldin (who served for the entirety of the Clinton administration and briefly for both Bush administrations) and James Fletcher (serving Nixon, Ford, Carter, and returning under President Reagan to get the agency back on track after Challenger.)  A new Democrat president would probably sack Griffin for no other reason than his ties to President Bush.  Then again, there's a good shot that Mike Griffin's tenure might not make it to January 2009, if Richard Shelby's comments are any indication.

Both parties appear to be split on space exploration.  Among Democrats, there's a desire to appear "pro-science" by supporting certain space efforts, but there's also a belief that manned spaceflight steals money from social programs.  Republicans are spilt too; many feel nostalgia for "the good old days" when a nationalist-driven space program was a key aspect of foreign policy, but others view manned spaceflight as wasteful government spending that should be left to the private sector to handle.

In terms of finding support for DIRECT, I'm certain that very few politicians really care about it.  A few Senators like Mikulski, Hutchinson and Bill Nelson have expressed frustration about the gap between Shuttle and Orion, and they might be attracted to DIRECT.  The rest are either apathetic towards space, or they have the James Sensenbrenner attitude that "NASA's the big boys, and they know what they're doing."

As much as I like DIRECT, I think its odds of being adopted are a long-shot, at best.  While talking to legislative aides is worth a shot, I don't think that Congress will force NASA to take any corrective actions regarding VSE.  DIRECT's best shot is a change of leadership at NASA--something that's sorely needed, but not likely to come in time to stop The Stick.
Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/13/2007 02:53 AM
Might I suggest that it would be a good idea to have a separate thread for DIRECT v2 speculation as versus Q&A on the baseline proposal?

That might reduce the confusion produced in the last Direct thread.

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=7900&posts=1&start=1


Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/13/2007 03:50 AM
Would it be possible to do a pro/con comparison between the DIRECT proposed EDS and the ESAS proposed EDS? JIS and others have raised this issue here and in the old thread and perhaps a more through analysis may shed some light on the selection. My concern is the development time especially.
Title: Re: DIRECT v2.0
Post by: on 05/13/2007 06:22 AM

Quote
CFE - 12/5/2007  3:49 PM  Then again, there's a good shot that Mike Griffin's tenure might not make it to January 2009, if Richard Shelby's comments are any indication.
Not everyone likes Mike ... anymore. Even if he does great speeches.

Both parties have segments that favor / disfavor space - for completely different reasons, with very specific agendas. Current administration in the short term fears losing control of the agenda, in the long term of being blamed for allowing China/Russia/whoever to have superseded the US by being too shortsighted (which is ironic considering Ares I). They alternate between panic (we're in trouble - pay any cost) and complacency (nothing really to worry about lets put things off and be cheap). Their rivals view it as an alternative that can sublimate other conflicts, so they can be viewed as strong nationally without needing to play the bully game, but get conflicted by competing agendas as they try to do too much with too little and overreach.
 

Both have constituents that consider space a waste of their time and of budget.  Both drive pork to favored groups. Both get hurt eventually by bad decisions. The pragmatists of either are where all the action is - they are realists, who can use DIRECT to hammer. The conformists like Sensenbrenner use ridicule to undercut any rationale for change, yet is himself vulnerable to ridicule - he turns about very fast when he's been undercut before.

Quote
As much as I like DIRECT, I think its odds of being adopted are a long-shot, at best.  While talking to legislative aides is worth a shot, I don't think that Congress will force NASA to take any corrective actions regarding VSE.  DIRECT's best shot is a change of leadership at NASA--something that's sorely needed, but not likely to come in time to stop The Stick.
Quite a fair conservative read, although it undervalues the malaise many feel of this moment. Also, DIRECT is very appealing for its simple directness that all politicos appreciate, and for that must certainly annoy HQ - like Man In Space Soonest, its very to the point, and when you kill it, you tend to kill parts of your current program too.

The Stick is as well cursed by too much of a "go slow" mentality that invariably leads to cancellation, as there's to little to work with conceptually to get somewhere fast enough (cf. complacency above). If it were a broader concept, it might simply be driven through to completion like some past projects. But one fears the "death of a thousand cuts" with it.

Still have considerable optimism of DIRECT getting a real chance, all said. Glad that good people have done a "Plan B" that's better than "Plan A" :laugh:  

Title: Re: DIRECT v2.0
Post by: clongton on 05/13/2007 12:17 PM
Quote
Norm Hartnett - 12/5/2007  11:50 PM

Would it be possible to do a pro/con comparison between the DIRECT proposed EDS and the ESAS proposed EDS? JIS and others have raised this issue here and in the old thread and perhaps a more through analysis may shed some light on the selection. My concern is the development time especially.
The EDS in the DIRECT proposal is based on the LM ICES stage. While that stage is not yet flying, it is an actual piece of hardware that is already in development by the Atlas/Centaur Advanced Systems Development team. The ICES is a logical extension of already flying hardware, and introduces no "new" technology. While this is an over-simplification, it is essentially an up-scale of the existing stages, introducing greater flexability and lift capacity. Whether Direct uses it or not, the ICES is already planned to fly on the Atlas-V. It has been in the LM Business Plan for a while now. The main difference between the LM ICES and the Direct ICES is the power plant. The standard ICES uses the RL-10 engine, while Direct's Jupiter uses the J-2X. Communications with the Atlas/Centaur team confirm that this configuration is completely workable, but would remain only semi-compatable with the RL-10 version, because of the differences needed for the more powerful engine.

By contrast, the ESAS EDS is a completely new design, while the ICES is already in the works. It is an example of NASA's unwise practice of placing multiple new technologies on the critical path to enable a FIRST launch of anything. One of the mantras of the Direct team was, before we assembled ANYTHING, we took a long hard look around at what we already have that could be adapted. In the near term, there was no getting away from a J-2X powerplant, or its equivilant, but we concluded that there was no need whatsoever to create a brand new stage when the LM ICES was so near to completion and so completely compatable. Additionally, the ESAS EDS used separate tankage, while the ICES uses a common bulkhead, a far superior design. LM has vast experience in managing and controling boiloff, and we considered it exceptionally wastful to the extreme to ignore existing capability and go off and duplicate it by developing something completely new at great expense. But then again, isn't that exactly what they are doing with the Ares-I?

Don't forget that the upper stage being developed for the Ares-I isn't the same stage as the EDS. The Ares-I stage is a 5m stage with a single engine, while the EDS is much larger. NASA is developing a stage with no commonality to the Ares-V, excepting the engine. More wasteful new technology on the critical path.

I would also like to point out that totally related to NASA's practice of baselineing multiple new technologies on the critical path, is the 1st launch date for Orion. Because of the approach they are taking, the Orion cannot possibly become opperational before the fall of 2015 at the earliest, and will probably slip even further, to 2016 or beyond. In contrast, by using the common sence approach of adapting existing flight hardware in lieu of developing new, Orion can fly on the Jupiter by September of 2012, a full three years earlier than the earliest possible date on the Ares-I. If the trend at NASA continues, it's even possible that the Jupiter could actually be capable of flying a lunar mission before the Ares-I even gets off the ground with Orion. That's what happens when you put new technology on the critical path to a first flight. Direct needs no new technology by adapting what we already have. The J-2X, while new, is not on the critical path, and not needed until much later. It can be developed at a pace more in-line with existing budget realities.
Title: Re: DIRECT v2.0
Post by: rumble on 05/13/2007 03:57 PM
The Ares-V seems to have changed its design point from a 90-day on-orbit loiter time to a 14-day time.  There is a tremendous difference in assumed propellant boil-off rates for the EDS for these two different durations.

What is the projected reasonable loiter time for the Jupiter ICES EDS?
Title: Re: DIRECT v2.0
Post by: William Graham on 05/13/2007 04:04 PM
Would it be feasable to carry, for example, a comsat with a PAM as a secondary payload on LEO flights with DIRECT? (if the comsat and PAM upper stage are carried in the space under the Orion spacecraft)
Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/13/2007 04:14 PM
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GW_Simulations - 13/5/2007  5:04 PM

Would it be feasable to carry, for example, a comsat with a PAM as a secondary payload on LEO flights with DIRECT? (if the comsat and PAM upper stage are carried in the space under the Orion spacecraft)

NASA's mantra is 'no crew and cargo'. In order to sell DIRECT to them it's best to avoid these sorts of suggestions.
The definition of 'no crew and cargo', and the rationale behind it, have been bashed out thoroughly in other threads already.
Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/13/2007 04:53 PM
Would the 120 launcher supporting a CEV with a upgraded SM containing extra consumables produce Orion mission capability for reaching NEO targets, Hubble service missions, and things of that nature? :D


In any case my question remains. If the Service Module can be more than doubled what kinds of mission capabilities does this bring to the Orion? I am not talking about a Mission module nor cargo per say but rather things like an eva tool box, repair parts for the Hubble/Web telescopes, possibly additional non-pressurized fittings for the ISS, replacement cameras and the like. Not to mention the possibility of the increased range for missions to the Lagrange points or NEO objects.

For unmanned cargo flights to the ISS a larger SM could haul pallets for external experiments for the Columbus and Kibo labs as well as repair parts that do not need to be in the pressurized capsule. By packing the available space in the SM with external garbage it might be possible to reduce the risky business of jetsoning parts over the side of the ISS and allow a more controled disposal of such items.


Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/13/2007 05:22 PM
Other than the planned AIAA presentation and word of mouth here and at other space forums what plans have been made for distribution of DIRECT v2? Candidates that occur to me are the union representitives at KSC and MAF (and possibly ATK) as well as the Congressmen of those locations. I suspect it is a bit early for me to print the proposal and mail it to my congressman and Senators but would such an effort be of value once the proposal has reached a mature state?

Title: RE: DIRECT v2.0
Post by: kraisee on 05/13/2007 08:03 PM
Quote
On a different thread, Norm Hartnett - 12/5/2007  10:56 PM

Might I suggest that it would be a good idea to have a separate thread for DIRECT v2 speculation as versus Q&A on the baseline proposal?

Would the 120 launcher supporting a CEV with a upgraded SM containing extra consumables produce Orion mission capability for reaching NEO targets, Hubble service missions, and things of that nature? :D

Hubble and all likely LEO missions should be supportable by the Jupiter 120 configuration.   The Jupiter has performance capability sufficient to launch about 23mT to orbit with a full CEV.

There are a number of missions which Jupiter-120 could immediately support, but which Ares-I makes impossible.   The three MPLM's which have proven so useful on Shuttle, could be flown to the ISS one more time - though they would not be recoverable afterwards.   They could offer a means of flying very heavy pressurized equipment & science racks to ISS after Shuttle retires.   The Russian Science Power Platform could actually be flown on a 120 mission.   And new cameras and heavy hardware could be flown to Hubble in the future to keep it serviceable.   Ares-I will always require an extra launch of one of the $150-250m EELV fleet to place the payload in orbit ahead of the crew flight.

NEO missions are trickier.   They are closer in requirements to a Lunar landing profile.   You need an Earth Departure Stage and a module designed to approach and land on the surface of an NEO, so you're likely to need a variant of the LSAM (an NEO Surface Access Module for want of a better name) to go with you.

Depending on the orbit of an NEO, it might be possible to fly the CEV, NSAM and EDS all on one flight of a 232 though.

Ross.
Title: Re: DIRECT v2.0
Post by: Jorge on 05/13/2007 08:39 PM
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Kaputnik - 13/5/2007  11:14 AM

Quote
GW_Simulations - 13/5/2007  5:04 PM

Would it be feasable to carry, for example, a comsat with a PAM as a secondary payload on LEO flights with DIRECT? (if the comsat and PAM upper stage are carried in the space under the Orion spacecraft)

NASA's mantra is 'no crew and cargo'. In order to sell DIRECT to them it's best to avoid these sorts of suggestions.
The definition of 'no crew and cargo', and the rationale behind it, have been bashed out thoroughly in other threads already.

Besides, what he's suggesting is illegal. The US government is forbidden from carrying commercial payloads on government launchers, with a narrowly defined exception for shuttle-unique payloads.
--
JRF
Title: Re: DIRECT v2.0
Post by: Thorny on 05/13/2007 08:51 PM
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Jorge - 13/5/2007  3:39 PM

Besides, what he's suggesting is illegal. The US government is forbidden from carrying commercial payloads on government launchers, with a narrowly defined exception for shuttle-unique payloads.
--
JRF

True, but if they wanted to, they might be able to double-talk their way around that problem by declaring Ares a USA/ULA vehicle and therefore commercial... afterall, Delta IV doesn't have any commercial customers, either.

Not that I'm advocating that idea.

Title: Re: DIRECT v2.0
Post by: Jim on 05/13/2007 09:19 PM
Quote
Norm Hartnett - 13/5/2007  12:53 PM

In any case my question remains. If the Service Module can be more than doubled what kinds of mission capabilities does this bring to the Orion? I am not talking about a Mission module nor cargo per say but rather things like an eva tool box, repair parts for the Hubble/Web telescopes, possibly additional non-pressurized fittings for the ISS, replacement cameras and the like. Not to mention the possibility of the increased range for missions to the Lagrange points or NEO objects.


Repair of spacecraft is not CEV mission.  And probability wouldn't be.  It is not economical, and there are very few spacecraft within range of it.  HST is not the norm for most spacecraft.  It was only placed in an orbit accessable by the shuttle so it can repair it.  If the orbit were based on science requirements, it would be in a much higher orbit (L2 for example)
Title: Re: DIRECT v2.0
Post by: Jim on 05/13/2007 09:22 PM
Quote
Thorny - 13/5/2007  4:51 PM


True, but if they wanted to, they might be able to double-talk their way around that problem by declaring Ares a USA/ULA vehicle and therefore commercial...


It can not  be a ULA nor a USA vehicle.
1.  ULA won't make any stages of Ares
2.  USA only operates the vehicle not own it
Title: Re: DIRECT v2.0
Post by: CFE on 05/14/2007 12:41 AM
It is a bit odd that Boeing and LockMart can team up for ULA, but they're competing against each other for the Ares I upper stage.

In terms of building Jupiter, it would appear that the contractors have already been picked out.  LockMart would build the core at Michoud, PW-Rocketdyne would produce the first stage engines, and ATK has the SRB's.  The upper stage could be subject to competitive bidding, but I assume that the ICES concept originated with LockMart, and it's little wonder who would win that contract.

Of course, the way to ensure Jupiter's survival through Congress is to make sure that all fifty states have at least one factory contributing to the new booster.
Title: Re: DIRECT v2.0
Post by: Jim on 05/14/2007 12:49 AM
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CFE - 13/5/2007  8:41 PM

It is a bit odd that Boeing and LockMart can team up for ULA, but they're competing against each other for the Ares I upper stage.

In terms of building Jupiter, it would appear that the contractors have already been picked out.  LockMart would build the core at Michoud, PW-Rocketdyne would produce the first stage engines, and ATK has the SRB's.  The upper stage could be subject to competitive bidding, but I assume that the ICES concept originated with LockMart, and it's little wonder who would win that contract.

Of course, the way to ensure Jupiter's survival through Congress is to make sure that all fifty states have at least one factory contributing to the new booster.

ULA is a separate company, just like USA.  From both companies but separate

Lockheed would NOT build the core.  Tust because they built the ET, There is no guarantee for them,
Title: Re: DIRECT v2.0
Post by: Thorny on 05/14/2007 01:05 AM
Quote
Jim - 13/5/2007  4:22 PM

Quote
Thorny - 13/5/2007  4:51 PM


True, but if they wanted to, they might be able to double-talk their way around that problem by declaring Ares a USA/ULA vehicle and therefore commercial...


It can not  be a ULA nor a USA vehicle.
1.  ULA won't make any stages of Ares
2.  USA only operates the vehicle not own it

Not as it is today (or is to be) but that's all just a paperwork issue. Not a ULA vehicle? The upper stage will either be Boeing or Lockmart at Michoud. It would take them, what, a few months to tweak the corporate structure to fold that operation under the ULA banner? They'd have to get ATK on board, but do you really think ATK would say, "No, sorry, we don't want to sell any more SRBs?" If USA in 2001 had told NASA, "You've cut us back to five Shuttle flights a year. We've demonstrated we can do seven or eight, so we'd like to foot the bill to launch commercial payloads on two or three flights a year." Do you honestly think NASA or Congress would have said, "No, we won't let you." They would have said "How soon can you implement this?" When challenged about the legality, they'd have said "We're not launching commercial payloads, USA is, and they're a commercial outfit."

NASA has bent the rules for Shuttle too many times to count. To say today that Ares I cannot be a ULA nor USA vehicle seems to me foolhardy. They can, and most likely will, do whatever they feel is in the best interest of Ares. (They've already totally ignored the EELVs, so Commercial Ares is only a minor step beyond that from their perspective.) There were various proposals, even after Challenger, for commercial operators to buy a fifth Shuttle for launching commercial payloads. They didn't go very far for many reasons, but it isn't immediately obvious that those reasons (high cost, crew requirements, low flight rate, etc.) are applicable to Ares I. I don't see the original poster's suggestion of "ride-along" comsat payloads as being realistic, but commercial flights of Ares I? I wouldn't dismiss that quite so readily. Especially if, say, Boeing pulls the plug on its money-losing Delta IV in the next couple of years.




Title: Re: DIRECT v2.0
Post by: Jim on 05/14/2007 01:29 AM
Quote
Thorny - 13/5/2007  9:05 PM

Not as it is today (or is to be) but that's all just a paperwork issue. Not a ULA vehicle? The upper stage will either be Boeing or Lockmart at Michoud. It would take them, what, a few months to tweak the corporate structure to fold that operation under the ULA banner? They'd have to get ATK on board, but do you really think ATK would say, "No, sorry, we don't want to sell any more SRBs?" If USA in 2001 had told NASA, "You've cut us back to five Shuttle flights a year. We've demonstrated we can do seven or eight, so we'd like to foot the bill to launch commercial payloads on two or three flights a year." Do you honestly think NASA or Congress would have said, "No, we won't let you." They would have said "How soon can you implement this?" When challenged about the legality, they'd have said "We're not launching commercial payloads, USA is, and they're a commercial outfit."

NASA has bent the rules for Shuttle too many times to count. To say today that Ares I cannot be a ULA nor USA vehicle seems to me foolhardy. They can, and most likely will, do whatever they feel is in the best interest of Ares. (They've already totally ignored the EELVs, so Commercial Ares is only a minor step beyond that from their perspective.) There were various proposals, even after Challenger, for commercial operators to buy a fifth Shuttle for launching commercial payloads. They didn't go very far for many reasons, but it isn't immediately obvious that those reasons (high cost, crew requirements, low flight rate, etc.) are applicable to Ares I. I don't see the original poster's suggestion of "ride-along" comsat payloads as being realistic, but commercial flights of Ares I? I wouldn't dismiss that quite so readily. Especially if, say, Boeing pulls the plug on its money-losing Delta IV in the next couple of years.


All wrong.  More than a paperwork issue.  

ULA is not going to be given the upperstage work from Boeing or LM because they then they would have to split the profits.

ATK is not going to get onboard for the same reason, sharing profits.

ULA is for EELV's and nothing else.

USA thought about doing  that but 1.  shuttle is not a USA only vehicle, NASA provide alot of support.  and 2 it was against the law.  3.  USA is commercial but not the shuttle   4.  Costs would be too high  for users.  5.  No use of a manned vehicle for simple comsat launches

And congress would have said no, just like they keep telling NASA to use more commercially services:  COTS, EELV's

USA will launch the Ares but like the shuttle NASA is too involved.  

Ares I can't compete commerically costwise, legally and performance wise.
 (high cost,  low flight rate, etc.) are directly applicable to Ares I.
Title: Re: DIRECT v2.0
Post by: Thorny on 05/14/2007 02:12 AM
Quote
Jim - 13/5/2007  8:29 PM

All wrong.  More than a paperwork issue.  

ULA is not going to be given the upperstage work from Boeing or LM because they then they would have to split the profits.

ATK is not going to get onboard for the same reason, sharing profits.

ULA is for EELV's and nothing else.

Today, yes.

Who among us five years ago dreamed ULA would even exist? Boeing and LockMart, arch-rivals, working in tandem to sell Deltas and Atlases? Unheard of! Never gonna happen! About as likely as Boeing and Airbus teaming up to build the new 737/A320 replacement, if you'd asked me...

Faced with losing all profit by not winning Ares I S2, is it inconceivable that Boeing and LockMart would decide to jointly bid on the contract through ULA? It wouldn't take all that much effort for NASA to tell them "we want ULA to build Ares I S2, make it happen or we're giving the contract to SpaceX or Orbital..."

Stranger things have happened. That's how we got ULA in the first place. (DoD strongarming when Boeing wanted to pull the plug on Delta IV.)

Quote
Jim - 13/5/2007  8:29 PM

And congress would have said no, just like they keep telling NASA to use more commercially services:  COTS, EELV's

Which NASA shrugged off when it came up with Ares. And NASA still has Cargo Orion on the backburner. Doesn't sound to me as though NASA cares all that much about Congress's direction, especially when a good lawyer can blur those "it's illegal" charges with some fancy, "But ULA is a commercial operator, we're just buying Orion launches from them..." language.

Quote
Jim - 13/5/2007  8:29 PM

Ares I can't compete commerically costwise, legally and performance wise.
 (high cost,  low flight rate, etc.) are directly applicable to Ares I.

I don't think "low flight rate" applies to Ares I at all, at least, not if it were open to commercial operations. We're already launching ten SRBs a year (five Shuttle flights) and Shuttle has gotten up to 8 per year in the last decade, that's 16 SRBs a year. That's a considerably higher flight rate than Atlas V or Delta IV have demonstrated.
Title: Re: DIRECT v2.0
Post by: clongton on 05/14/2007 02:16 AM
Let's get back on-topic here please. This is not an Ares-I thread.
Title: Re: DIRECT v2.0
Post by: Steve G on 05/14/2007 04:00 AM
This is not a suggestion.  I’m just curious.
What would be;

a)   The performance of a 2 x standard SRB’s and a single RS-68 assuming the tank size would have a narrower diameter but the same height to be launch pad compatible.
b)   The performance for lunar and mars mission (Ballpark since Mars varies so much) with a Centaur upperstage or an J-2X "D"?
c)   Ballpark development cost (and is it even possible)

Like I said, just curious.
Title: Re: DIRECT v2.0
Post by: Jorge on 05/14/2007 04:37 AM
Quote
Steve G - 13/5/2007  11:00 PM

This is not a suggestion.  I’m just curious.
What would be;

a)   The performance of a 2 x standard SRB’s and a single RS-68 assuming the tank size would have a narrower diameter but the same height to be launch pad compatible.

I'm not sure I understand this statement. To be launch pad compatible the spacing between the SRBs needs to be the same, implying same diameter, not narrower.
--
JRF
Title: Re: DIRECT v2.0
Post by: CFE on 05/14/2007 04:48 AM
The vehicle described by Steve G would need longer struts between the SRB's and core, if it were to reuse the Shuttle MLP without changes to the SRB mounts.  I would think that these longer struts would need to be a lot beefier to resist the additional torsion.  It's really not worth it, IMHO.  

The number of engines on the Jupiter core was set as it was for a good reason.  It's the best combination of thrust to lift the vehicle off the pad and minimize gravity losses on ascent, without burdening the design by adding the extra mass and complexity that are associated with superfluous, additional engines.
Title: Re: DIRECT v2.0
Post by: Steve G on 05/14/2007 05:04 AM
I realized as I was writing this that the smaller diameter tank wouldn't fit the pad!  However, (I'm relying on a very distant memory here) I seem to recall that Hughes wanted to propose a Jarvis ELV for some Navy navigation satellites that the Delta II eventually won.  But it was based on 2 F1 engines and then a single J2.  Then, the final proposal changed to a standard shuttle stack with a single SSME at the base of the ET.  I’m assuming they were planning to use a standard ET to by flown only partially fuelled.

If a smaller single RS68 version of the Jupiter was proposed, it would be a lot easier (and less R&D) to keep a common tank and eat the lost performance for the sake of $Billions making a smaller tank.
Title: Re: DIRECT v2.0
Post by: Steve G on 05/14/2007 05:40 AM
As I stated in another thread, I’m no rocket scientist.  But I have been a space enthusiast for over 40 years and have scrap books going back as far with magazine and newspaper clippings.  I was a member of the Mars Society and when I lived in Montreal, got to meet Marc Garneau, the only astronaut I ever met.

Besides being a spaceflight and astronomy geek I was also involved in politics.  Being in Quebec, there’s no shortage and I started a group to fight the separation movement by trying to get the federal government to change it’s benign policy of putting its head in the dirt and pretending that separatists don’t exist, and set the rules.

I don’t want to bore you guy with the particulars, but I really got involved.  I had a bomb threat made on my home.  I joined a group headed by some of the best constitutional experts in the land.  The media and government thought we were dangerous radicals when all we proposed was a common sense proposal to set the rules of secession.  We had packed rallies that were blackballed by the media.  But when the separatists nearly won the 1995 referendum and our country was within a half percentage point of being split up, people started buying our message.  Including the prime minister.  They bought our program, the Supreme Court endorsed it and parliament passed a “Clarity Act” based nearly word for word from what we had been saying all along.  Of course, we never got the credit, it didn’t matter.  We won.

The Direct proposal isn’t brilliant.  It’s the only logical course to follow.  The proposal and work is brilliant.  All I’m saying is that if 12 people with enough passion can save a country, you guys can save your space program.  You have to blitz your proposal to the workers at all of the shuttle facilities whose job will be saved, to the mayors, congressmen, and governors whose state will be affected, to influential organizations such as the Planetary Society and even Larry King.

If John Young (what does he know, he’s only been to the moon TWICE!) that this month could be decisive.  Your plan serves the interest of not just the nation, but to the politicians whose constituents will retain their jobs.  You need to break some seemingly impenetrable barriers and it won’t be easy.  I know from experience that it can be done, and I tell you, that evening in January 1996 when we made our breakthrough, it makes it all worthwhile.  It felt damn good, like a first kiss.

Go for it.  America is counting on you.
Title: Re: DIRECT v2.0
Post by: MATTBLAK on 05/14/2007 07:58 AM
Amen!!
Title: Re: DIRECT v2.0
Post by: neviden on 05/14/2007 05:48 PM
I like this architecture more than Ares V/I. But to improve it, you should focus on things that it can do, that Ares V/I can’t do. To show possible paths for eventual cost reductions, for future missions, for extra capabilities. I would emphasize the following:

- CEV could have its tanks increased, so it could carry maximum Jupiter 120 load to ISS Delivery orbit. That would mean it would have delta-v capability of 3-4 km/s. This would not go against “no crew and cargo”, since the cargo would be propellant that would be in the CEV anyway. This could achive:

a) It could use this propellant to raise ISS orbit (“national laboratory” and all this, means it will be around for some time). NASA could “barter” that capacity for cargo deliveries on ATV/Progress/HTV (ATV could then carry more of the other things and not have to carry orbit raising propellant for example).

b) It would mean that there is one “stand-by” rescue CEV always on orbit (attached to ISS, raising it’s orbit only when it’s time to return the crew back to Earth on the end of it’s on orbit life.), ready to come to the rescue if there would be any problems on any other spaceships in any possible Earth orbit.

c) It could do some kind of “international” crew missions. It would deliver US crews to ISS. After 12 months (or whatever the ‘on-orbit storage’ time would be), the US crew returns with Soyuz (cheap), Russian crew rides on Orion to LLO. Moon crew exchange mission for a price of a Soyuz (and a lander of course).

- CEV could get into LLO earth orbit by itself. If the moon lander could be refilled (by moon propellants) and reused, that would mean cost reductions in the future.

- CEV itself could actually do TEI by itself and return by itself (it would be a little cramped, but could be done in an emergency).

- CEV could allow staging of future TEI missions from High Earth Orbits (L1, L2, HEEO). That would allow high isp/low thrust propulsions (NEP, SEP) to be more viable. Big spaceships could be assembled in LEO in 100 MT pieces, take it’s time to cycle through Van Allen radiation belt to High Earth Orbit (months). The crew could then go directly to that spaceship when it would be ready to start it’s manned mission (and would need only small thrust to achieve TEI).

High Earth Orbit is the key (in my opinion) to the sustainable space exploration and exploitation. This has nothing to do with DIRECT, but it would fit into it much better than the Ares V/I system. By showing that it could achieve more than the Ares V/I combination for less development money, be ready for major missions beyond Earth orbit and have capability for upgrades (5 segment boosters, engines) it would have a shoot at being seriously considered.
Title: Re: DIRECT v2.0
Post by: Lunar Dreamer on 05/14/2007 05:59 PM
Bottom line, if NASA decided stop Ares I at the end of this year and set Direct up from Jan 2008, how soon would we have a Shuttle replacement ready to launch.

I know this is hugely unlikely, but just pretend in this scenario.
Title: Re: DIRECT v2.0
Post by: clongton on 05/14/2007 06:06 PM
Quote
Lunar Dreamer - 14/5/2007  1:59 PM

Bottom line, if NASA decided stop Ares I at the end of this year and set Direct up from Jan 2008, how soon would we have a Shuttle replacement ready to launch.

Current projections are that Orion would become operational by 2012.
That's only a 24 month gap after Shuttle , and a minimum of 3 years ahead of Ares-I, probably more.

And that's on a launch vehicle capable of taking Orion to the moon as soon as the upper stage is ready.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/14/2007 06:36 PM
NASA could move a lot faster by going straight to the experienced personnel working on the STS External Tank and getting their advice.

They have current experience with most of the elements right now, have experience of the changes to ET which occurred during the Light Weight Tank development program and later the Super Light Weight Tank development program - all of which is immediately applicable knowledge for Jupiter stage design.

MSFC's role should be oversight of course, so the DDT&E work for Jupiter Common Core stages should all go to Michoud.

That doesn't mean that MSFC loses work - hell no.   The team in place right now working on the Ares-I Upper Stage is *perfectly* placed to start work on the EDS.   They are currently working with industry to create a fairly large diameter upper stage, to be powered by a J-2X engine.   Who better to start on the EDS work?   With the ICES technology in the mix, I wouldn't be surprised if the team at Marshall could make the EDS fully operational for lunar missions noticeably sooner than 2017 - which is the current DIRECT manifested schedule.

Ross.
Title: Re: DIRECT v2.0
Post by: clongton on 05/14/2007 06:57 PM
***************
CALL FOR CRITIQUE
***************   

Ok, everyone’s had some time to look this over and think about it.
Now what we are asking of you all is some serious critique. We need a solid peer review from the space community – from you folks.

Some of you are very highly placed in NASA, its field centers, and its contractors and some of you have academic pedigrees longer than my arm. Some of you are subject matter experts and very hands-on to the actual flight hardware. This is what you do. There are folks on this forum from Stennis, ATK, MSFC, Glenn, JPL, LM, Boeing, MAF, KSC and NASA HQ. Some of you are in congressional offices. I’m sure I missed some, so please accept my apologies. Some of you are just enthusiasts, but your knowledge of the space program spans decades and is an invaluable contribution. And some of you "just work there", but you know, see and hear things that are sometimes not common knowledge.

We need your expertise, all of you.

We have run the numbers every way we can think of, and used some of the most sophisticated tools that exist to do that. But output is no better than input, and hundreds of eyes are better than a dozen or so.

Please take this proposal apart, examine it closely, from every angle you can think of. Put new batteries in your calculators and run the numbers. Some of you have access to POST and can work the trajectories. Some of you have finances in your blood and you can run the financials. Some of you work intimately with the RS-68, and some of you know what ammonium perclorate smells like in your sleep. Some of you run equations in your heads just for fun. We need you, all of you, and in our opinion, the future of manned spaceflight in this country needs you as well.

Please, look this proposal over very carefully, and tell us what you find. If it’s a negative, we need to know that so we can fix it. We have been eating and sleeping this proposal for months now and we may very well have missed some things, simply because we are so very close to it. We need your objectivity.

Please take the proposal apart and put it back together again; see if you can find anything that is a showstopper. If you do, tell us. Put it out there for us all to discuss. We put this proposal together, but it isn't just ours. It's ALL of ours.

We have put together what we believe is a very good proposal. But who knows? Only you do. Obviously, we are biased in our opinion, but we can be and are open to instruction and correction, as required.

We place before you the DIRECT Alternative Architecture and the Jupiter Launch Vehicle for your very highly valued consideration.
Title: Re: DIRECT v2.0
Post by: nathan.moeller on 05/14/2007 07:06 PM
Nice Chuck.  I believe I fall under 'enthusiast' ;)  But be straight with me.  What kind of odds would you give this proposal?  How likely is it that Direct will replace Ares?  Don't get me wrong.  I love this Direct system.  You guys have done so incredibly well putting this together and I'd love to see it someday.  But what are its chances?
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/14/2007 07:25 PM
You know, you guys have some really beautiful artwork there.  How about sending some framed, "suitable for hanging on your wall" versions of it to some of the key decision-makers?  Having the bird hanging on their office walls could go a long, long way towards moving their thought process in the DIRECT direction.  Think of how much effect effect Chesley Bonestell's art had on the beginnings of the space program.
Title: Re: DIRECT v2.0
Post by: simcosmos on 05/14/2007 07:50 PM
About the feedback: I do have some comments, questions, etc that would like to do about Direct v2.0. Chuck (Direct Team), you will probably have something to read within some hours...

Thanks,
António
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/14/2007 07:54 PM
I am merely a follower of the space program.   I certainly can’t make any contribution on the designs or mission profiles.   I do have one concern for what its worth.   You project has become pretty high profile.   This may make it more difficult to have it looked at seriously.   You will definitely stepping on some toes.   Perhaps some input on how to approach the “sales job” would be helpful.   Anyone?
Title: Re: DIRECT v2.0
Post by: clongton on 05/14/2007 07:57 PM
Quote
Steve G - 13/5/2007  12:00 AM

This is not a suggestion.  I’m just curious. What would be;
a) The performance of a 2 x standard SRB’s and a single RS-68 assuming the tank size would have a narrower diameter but the same height to be launch pad compatible.
We actually worked that out, while keeping the ET diameter unchanged. It would be a Jupiter 110. It would be a direct competitor with the ELV fleet, so we decided not to go there. What Direct wants to do is to compliment and go beyond the ELV fleet, not compete with it.

At the end of the proposal and in this thread, we have alluded to the upcoming 2007 AIAA paper. In it are five driving imperatives which ultimately determined the design parameters of the Jupiter Launch Vehicle family.

From the paper (caution: WIP):

Imperative #3: Do not duplicate the lift capacity that is already available in the existing launch vehicles of the Evolved Expendable Launch Vehicle fleet.

Rational: The Evolved Expendable Launch Vehicle fleet, or EELV’s, are composed of Lockheed Martin’s Atlas launch vehicle families and the Boeing Delta series launch vehicles. Together, these launch vehicles easily and dependably lift from 10 to 25mT of payload to LEO. In addition, already planned variants of these families will be able to launch between 40 to 50mT of payload to the same orbits. These launch vehicles were fielded with a great deal of effort and budget, and are today the mainstay of the civilian robotic space program. In addition, the United States military and the US government also contract to fly payloads on these vehicles, some to LEO, some to geostationary orbits, and in the case of the robotic probes of the civilian program, to interplanetary trajectories. But the bottom line is once again lift capacity.

Goal: Since these vehicles are already capable of the 25mT capacity of Shuttle, and planned variants will be capable of 40 to 50mT, the third goal of Phase 1 must be to field a new launch vehicle that will not wastefully duplicate this capacity. So the low end of the new launch vehicle capacity should be not less than 40 to 50mT to Low Earth Orbit.
Title: Re: DIRECT v2.0
Post by: Ad Astra on 05/15/2007 04:04 AM
Why wasn't this proposal written up the second the ESAS report came out? What was the delay? What will you do if Dr Stanley comes on here and slaps this out of the ballpark like Direct 1? Will there then be a Direct 3, and 4 and 5? Are you banking on a Democrat win so as to be an alternative cheaper solution when Ares is cancelled due to money?

Lots of questions here, but I am impressed with your presentation. On face value it looks a lot more obvious and sensible.
Title: Re: DIRECT v2.0
Post by: CFE on 05/15/2007 04:14 AM
If I tried to get in the shoes of a NASA debunker, what would I identify as DIRECT's weakness?  The most obvious is the structural masses of the EDS.  NASA will say that the EDS structure is too light to be true.

While were on the topic of upper stages, I have to ask where Jupiter's avionics will be located.  I assume it will be in a ring between the top of the vehicle and the payload adapter.  The avionics will probably be shuttle-derived, too.
Title: Re: DIRECT v2.0
Post by: jongoff on 05/15/2007 04:34 AM
CFE,
Quote
If I tried to get in the shoes of a NASA debunker, what would I identify as DIRECT's weakness?  The most obvious is the structural masses of the EDS.  NASA will say that the EDS structure is too light to be true.

That's also what I would see as its key "weakness" in NASA's eyes.  Not that I don't believe those numbers are attainable (they are), but NASA didn't believe the ICES numbers the first time around during ESAS so they jacked the dry mass numbers up by IIRC a factor of ~2.  Of course, the danger for NASA in bringing this line of argument up is that *supposedly* their model also does not accurately predict the dry mass of the existing, flight-proven Centaur...so they could open up this line of debate, but they might be opening themselves up for claims of incompetence (or worse).  

~Jon
Title: Re: DIRECT v2.0
Post by: rumble on 05/15/2007 04:39 AM
Quote
Ad Astra - 14/5/2007  11:04 PM

What will you do if Dr Stanley comes on here and slaps this out of the ballpark like Direct 1?
I wouldn't go so far as to say he slapped DIRECT 1 out of the ballpark.  What he did do is identify & point out that the high performance numbers were based on a version of the RS-68 that turned out not to be true.  The (now known to be non-existent) 435s isp regen version of the RS-68 was the weak spot of the original DIRECT.  Doug spent the balance of his reply defending Ares I--not trying to dismantle DIRECT.  

DIRECT II is based on all currently-existing engines, with the exception of the J-2X(D), and the specs being used for it are the same as is being published by NASA for Ares I (274,000klbf and 448s isp).  The team working on DIRECT II didn't want to leave anything to chance this time.  If engine upgrades are available later, they'll only help DIRECT.
Title: Re: DIRECT v2.0
Post by: JIS on 05/15/2007 10:01 AM
Quote
jongoff - 15/5/2007  5:34 AM

CFE,
Quote
If I tried to get in the shoes of a NASA debunker, what would I identify as DIRECT's weakness?  The most obvious is the structural masses of the EDS.  NASA will say that the EDS structure is too light to be true.

That's also what I would see as its key "weakness" in NASA's eyes.  Not that I don't believe those numbers are attainable (they are), but NASA didn't believe the ICES numbers the first time around during ESAS so they jacked the dry mass numbers up by IIRC a factor of ~2.  Of course, the danger for NASA in bringing this line of argument up is that *supposedly* their model also does not accurately predict the dry mass of the existing, flight-proven Centaur...so they could open up this line of debate, but they might be opening themselves up for claims of incompetence (or worse).  

~Jon

However, it is NASA who decides what EDS will fly on it's booster. As the EDS technology would be the same for Ares 5 or Jupiter the Direct claims towards Ares V are not comparing apples to apples again.
Not only the EDS weight seems to be a bit low. As the core with two or three RS-68 is around for a long time it would be interresting to compare the core weight with other studies too. Jupiter has very heavy EDS (400mT ? when fuelled) and 100mT payload on the top. I'm wondering who did the stress analysis for the Direct.

Even the Jupiter fairing weights about 2.7 mT (8.4m diameter) while Atlas V fairing is 2.3mT for 4m diameter and 4.1mT for "short" 5m diameter fairing.

Anyway, I think that the most important drawback of the Direct architecture is a lack of it. Changes in Orion SM or additional spaceship to utilise CLV, smaller Moon delivered cargo in one launch, LOC etc.

A big mistake is the claim that the Ares V could be developed from Jupiter. This is clearly not an option. Another false claim is that the Direct can prevent the cancellation of the VSE. The biggest expense is not in the boosters but in the payload and the Lunar moon assembly. Tthe key factor is the delivery of the moon base elements (or mars ship elements later). If there is no money for Ares V there won't be enough money for any accelerated Direct architecture.

I'm certainly not saying that the Jupiter can't work. I was long supporter of a SDV vehicle with two RS-68 engines and I found less issues in the new Direct study than in the old one. I'm really looking forward to  any reaction from NASA (and next version of the Direct study).
Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/15/2007 10:36 AM
Well, my comments are made on the assumption that it is Mike Griffin reading the proposal, not a member of congress of another non-connected person, and they really concern how you are 'selling' DIRECT.

Essentially, I think the proposal should outline DIRECT on its own merits first, and then include comparisons to Ares later on, perhaps in a tabular form so that the language cannot be construed as confrontational. At the moment it does appear a little arrogant, and in particular by discussing safety first, I think this could give the reader the wrong impression. The proposal should start by talking about the things that cannot be argued against- the increased commonality, reduced spaceflight gap, etc. A short discussion later in the proposal of the various aspects that are in DIRECT's favour when it comes to safety might be more appropriate.

That's all for just now... good luck!
Title: Re: DIRECT v2.0
Post by: Jim on 05/15/2007 12:01 PM
Quote
CFE - 14/5/2007  12:14 AM
  The avionics will probably be shuttle-derived, too.

They will  be new.  Shuttle avionics are outdated and hard to maintain
Title: Re: DIRECT v2.0
Post by: jongoff on 05/15/2007 02:08 PM
JIS,
Quote
However, it is NASA who decides what EDS will fly on it's booster. As the EDS technology would be the same for Ares 5 or Jupiter the Direct claims towards Ares V are not comparing apples to apples again.

Not so much.  Remember, the EDS that is currently being planned is not the same EDS that was discussed in ESAS.  The ESAS EDS (as has been pointed out repeatedly here) uses two separate tanks, and a much less efficient structure.  The currently planned EDS has moved to a common bulkhead (as has the Ares I US), because it is so much more mass efficient.  Compare the Delta-IV US vs the Centaur for instance.  If you compared the current EDS numbers (however one would get them) with the proposed DIRECT EDS numbers, I bet they would come out pretty close.

Quote
Not only the EDS weight seems to be a bit low. As the core with two or three RS-68 is around for a long time it would be interresting to compare the core weight with other studies too. Jupiter has very heavy EDS (400mT ? when fuelled) and 100mT payload on the top. I'm wondering who did the stress analysis for the Direct.

I don't know who did the analysis, but Ross and Chuck both stated that such analysis was performed, and honestly I believe them.  This is something that's been studied a lot in the past, and I'd be amazed if the numbers were in any way "magic" as you like to say.  They said the walls would have to be thickened up a bit.  As I'm seeing it, the listed "Core stage dry mass" for DIRECT v2.0 is over twice the dry mass of the existing Shuttle ET.  I don't have the tools to do a complete stress analysis, but that sounds like a plausible ball park.

~Jon
Title: Re: DIRECT v2.0
Post by: imfan on 05/15/2007 02:43 PM
Quote
Ad Astra - 15/5/2007  6:04 AM

Why wasn't this proposal written up the second the ESAS report came out? What was the delay?

Because originally ESAS seemed to be direct, being based on the same ideas, which were abandoned one by one
Title: Re: DIRECT v2.0
Post by: meiza on 05/15/2007 03:27 PM
The Direct V2 document seems pretty sensible at first look.
Having the CEV do the LOI burn moves some mass from the unmanned launch to the manned one, which makes sense with Direct.
Title: Re: DIRECT v2.0
Post by: JIS on 05/15/2007 03:29 PM
Quote
jongoff - 15/5/2007  3:08 PM
If you compared the current EDS numbers (however one would get them) with the proposed DIRECT EDS numbers, I bet they would come out pretty close.

Ares V EDS weights about 36,000lbs and can hold about 500,000lbs of propellants.
Jupiter EDS weights about 45,000lbs and can hold about 800,000lbs of propellants.
One extra J-2X engine is about 4000lbs. This leaves 5,000 lbs in dry mass for extra 300,000 lbs of propellants. It doesn't look to me as "pretty close".
 


Quote
I don't know who did the analysis, but Ross and Chuck both stated that such analysis was performed, and honestly I believe them.  This is something that's been studied a lot in the past, and I'd be amazed if the numbers were in any way "magic" as you like to say.

I'm not saying it's magic. I just don't believe inconsistent numbers. As for Jupiter core there were so many different studies of this subject I would be surprised if the very similar configuration were not studied by NASA or some aerospace major already before. Certainly authors compared those results.
When you look at their own work - Direct v1 - the core has dry weight of 137 klbs. Direct v2 has 153.4 klbs. The difference is 16.4klbs. One ablative RS-68 weights about 14.klbs without any plumbing. Direct v1 had two regen RS-68, Direct v2 has three albative RS-68 so the transferred forces are also higher.
There are bigger discrepancies when comparing numbers with studies done by others. Everybody can make his own opinion.
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/15/2007 04:05 PM
Quote
Ad Astra - 14/5/2007  9:04 PM

Why wasn't this proposal written up the second the ESAS report came out? What was the delay? What will you do if Dr Stanley comes on here and slaps this out of the ballpark like Direct 1? Will there then be a Direct 3, and 4 and 5? Are you banking on a Democrat win so as to be an alternative cheaper solution when Ares is cancelled due to money?

Lots of questions here, but I am impressed with your presentation. On face value it looks a lot more obvious and sensible.

I showed something very close to “Direct” once during Sean O’Keefe and three times during Mike Griffin (twice before ESAS and one time after ESAS).  The idea was solid then and has only improved with all the additional refinements in launch infrastructure modification, programmatic and configurational work others have added to it since then.

From the grass roots level to just below the NASA Executive level “Direct” is very popular (better than 2/3 roughly).  I’m as confused as you are as to the problem with Direct at the high level.

Based on my take on these prior NASA-HQ meetings Sean’s boys didn’t like it because they were clearly going towards the all ELV approach.  From Mike’s boys they didn’t like it because they are pretty much Mars firsters so they wanted the largest vehicle that they could get (ie the Ares V).

That was the genesis of the Jupiter-3 by the way.  I showed them how two Jupiter-1’s could be used as boosters putting a single launch Mars mission package of two total launches (ISRU+Return  followed by Crew) via chemical EDS at about 350mT IMLEO per launch.  If I said there response was sophomoric I would be generous.  The loading dynamics on the Jupiter-3 is as about as close to three rockets going up independently as you could hope for.

The key issue is the pitch and roll maneuver prior to entering the gravity turn.  That and the infrastructure issues at KSC but I generally envision the launches from sea for this bad boy.  KSC will be over 50 years old and who knows how long before a Hurricane with its name on it takes it out.  The Jupiter-3’s center engines basically feed off the out Jupiter-1’s tank draining them at a similar rate as the Jupiter-242 does allowing for a near optimal second stage switching the center engines prior to staging to the center 2nd stage tank.

Having the heavier lifter use a common core booster with the lower end family members is a big advantage from a fixed cost stand point.

Again the Jupiter-3 may never happen and if it did it would be +25 years from now.  Lunar staging of the Jupiter-2 may be the actual way we go to Mars.  But part of me hopes that the future space program would actually need a vehicle capable of +350mT.

Title: Re: DIRECT v2.0
Post by: jongoff on 05/15/2007 05:17 PM
JIS,
Quote
Ares V EDS weights about 36,000lbs and can hold about 500,000lbs of propellants.
Jupiter EDS weights about 45,000lbs and can hold about 800,000lbs of propellants.
One extra J-2X engine is about 4000lbs. This leaves 5,000 lbs in dry mass for extra 300,000 lbs of propellants. It doesn't look to me as "pretty close".

Is that the ESAS Ares V EDS, or the current design Ares V EDS?  There should be a sizeable difference between the original ESAS Ares V EDS and the DIRECT EDS, since the DIRECT EDS uses a common bulkhead.  More importantly, it's jives pretty well with existing Centaur numbers I've seen.  The existing Centaur numbers have the tanks weighing in around 4% of the propellant mass (give or take), that would mean that after the tanks and the engines, you'd still have on the order of ~7000lb for the rest of the stage hardware like ACS systems, batteries, solar panels, etc, etc.

It could be that part of the EDS weight difference also stems from the fact that the Ares V EDS planned on using active cooling techniques because the tank manufacturing plan they had was a boiloff nightmare otherwise.

Between the fact that the DIRECT numbers jive well with actual flying hardware (the Centaur), and the other factors involved, I'm more inclined to believe the DIRECT numbers than the ESAS numbers.  The ESAS guys may be smart, but when their models disagree with existing hardware, their models are wrong.  Period.

Quote
When you look at their own work - Direct v1 - the core has dry weight of 137 klbs. Direct v2 has 153.4 klbs. The difference is 16.4klbs. One ablative RS-68 weights about 14.klbs without any plumbing. Direct v1 had two regen RS-68, Direct v2 has three albative RS-68 so the transferred forces are also higher.
There are bigger discrepancies when comparing numbers with studies done by others. Everybody can make his own opinion.

Wasn't DIRECT v1.0 also being designed with a 3 engine configuration in mind, and thus with the higher loads being factored in from the start just like DIRECT v2.0?  

~Jon
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/15/2007 09:45 PM
Quote
SMetch - 15/5/2007  9:05 AM
From Mike’s boys they didn’t like it because they are pretty much Mars firsters so they wanted the largest vehicle that they could get (ie the Ares V).

Have you (the DIRECT team) looked at how much one could lift if they did a "maximally-evolved" Jupiter?  I.e., with regen RS-68's running at 106%, the best version of the J-2 now on the boards, maybe an extra engine or two, and the maximum stretch you can do to the core and upper stages while still using the existing facilities or minor improvements?  I'm wondering how that would compare with the Ares V, for the "I want the biggest BFR I can get" folks.

Something I've noticed, looking at things like Atlas Phase III, Jupiter 3, Nova, and other big launchers, is that There Ain't No Such Thing As A Free Lunch.  The Atlas Phase III that launches ~140 mT is basically 4 of the strap-on boosters used on the ~70 mT Phase II (which uses 2 boosters), and a core that's twice as big.  In other words, there's not really any economy of scale here.  Running the 70 mT vs. 140 mT example, all you're really saving is that you only have to run one launch instead of two, and you don't have to rendezvous to either transfer propellant or connect two pieces together.  But, the cost is that you have to spend huge $$$ to develop a rocket that you're only going to launch a few times.

My point here is, what does the lift capacity of Ares V do for you, vs. DIRECT?  It appears that it saves maybe one or two launches per Mars mission.  For, what, maybe three or four trips to Mars, total?  When you look at it that way, there's really not much gain at all for all that expense and schedule impact.

(By the way, does anybody have any clue what a dry Mars stack, exclusive of Orion, might mass out at?)
Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/15/2007 10:42 PM
One thing that is lacking in Direct v2 compared to Direct v1 is the detailed infrastructure cost comparisons.

Since one of the major advantages of Direct is the cost and time saved in upgrading infrastructure this should be included and detailed by Center and transportation links.

I. Ares V tank mfg vs Direct tank mfg costs (apples to apples comparison).

   A. MAF:
1. Retooling costs for 10m tank vs retooling for 8.5 Direct tank (presumably engines will be mounted at MAF?)
2. Tank handling equipment modification for both variants at MAF.

   B. Transport to KSC:
1. New cargo carrier for 10m vs modification of existing carrier (if possible) for Direct tank.
2. Tank handling equipment modification for both variants at MAF port.
3. Tank handling equipment modification for both variants at KSC port.

   C. KSC:
1. Tank handling equipment modification for both variants at KSC.

II. Ares I and Ares V vs Direct assembly facility costs at KSC (an apple & apple to apple comparison)

A.   VAB modifications compared

III. Ares I and Ares V vs Direct launch facilities costs at KSC (an apple & apple to apple comparison)

A.   MLP modifications
B.   Crawler modifications
C.   Pad modifications

IV. SRB recovery facility costs (apples to apples comparison).

A.   Ship modifications
B.   Dock modifications

Care should be taken to focus this section on only the costs of fixed assets and presumptions should be clearly spelled out. Tables should be clear and legible and should make clear where the comparisons are being made. The final conclusion should be as clear-cut as possible. I am sure I missed several other facilities cost catagories.

While Ross’ graphics were excellent in the original Direct they were not as effective as good cost tables would have been IMO.

Title: Re: DIRECT v2.0
Post by: Smatcha on 05/15/2007 10:54 PM
Quote
SolarPowered - 15/5/2007  2:45 PM

Quote
SMetch - 15/5/2007  9:05 AM
From Mike’s boys they didn’t like it because they are pretty much Mars firsters so they wanted the largest vehicle that they could get (ie the Ares V).

Have you (the DIRECT team) looked at how much one could lift if they did a "maximally-evolved" Jupiter?  I.e., with regen RS-68's running at 106%, the best version of the J-2 now on the boards, maybe an extra engine or two, and the maximum stretch you can do to the core and upper stages while still using the existing facilities or minor improvements?  I'm wondering how that would compare with the Ares V, for the "I want the biggest BFR I can get" folks.

Something I've noticed, looking at things like Atlas Phase III and Jupiter 3, Nova, and other big launchers, is that There Ain't No Such Thing As A Free Lunch.  The Atlas Phase III that launches ~140 mT is basically 4 of the strap-on boosters used on the ~70 mT Phase II (which uses 2 boosters), and a core that's twice as big.  In other words, there's not really any economy of scale here.  Running the 70 mT vs. 140 mT example, all you're really saving is that you only have to run one launch instead of two, and you don't have to rendezvous to either transfer propellant or connect two pieces together.  But, the cost is that you have to spend huge $$$ to develop a rocket that you're only going to launch a few times.

My point here is, what does the lift capacity of Ares V do for you, vs. DIRECT?  It appears that it saves maybe one or two launches per Mars mission.  For, what, maybe three or four trips to Mars, total?  When you look at it that way, there's really not much gain at all for all that expense and schedule impact.

(By the way, does anybody have any clue what a dry Mars stack, exclusive of Orion, might mass out at?)

Yes a Jupiter-254 with a full high thrust second stage (final “3rd” stage does just the EOI and EDS like the Saturn V) can put more mass on a TLI than the Ares V.  The large 10m stretched tank of the Ares V takes longer to drain than the 8.4m standard length tank of the Jupiter so the Jupiter can take greater advantage of a true second stage (equal deltaV for equal ISP rocket 101 rule) increasing its payload mass fraction and total mass on a TLI (the only performance number that matters) over AresV.

On the built-up common core vehicles I agree.  It’s basically a trade off between LOM rate vs. common core integration/launch facilities vs. fewer if any Rendezvous/orbital timing issues (which bring up a whole host of LOM not related to the ascent).  Pick your poison.  It’s important to remember that spacecraft integration (cost, complexity, weight etc) is an issue with a more tinker toy approach.  Also payload volume and weight need to grow in a like fashion so 140mT under a 5m fairing doesn’t work.

Mars missions in a two launch architecture (Crew Ascent+ISRU) followed by (Crew+Surface Hab+In Space Return) range between 100 - 200mT each on a TMI depending on various assumptions.

The key is getting a Jupiter launch rate of between 4-10 per year.  That way we can burden a higher payload capacity (now possible by removing the worlds most complicated, expensive and heavy payload fairing ever – ie the Space Shuttle) over what is in fact a very high fixed cost of the KSC-STS system.  If you look at the actual money spent year to year on STS the launch rate has almost no influence on the total budget.  Work expands to fit the time available at NASA.  Whether its zero or eight launches per year the actual money spent changes only slightly.

A few more aluminum plates, more orange foam, a little more solid propellant, some LOX and LH2 doesn't drive the cost.  It’s the payroll, facilities maintenance, training etc. that drives the cost structure not the materials used by that largely fixed labor to make, field, fuel and fly the STS.


Title: Re: DIRECT v2.0
Post by: on 05/16/2007 12:08 AM

Quote
SMetch - 15/5/2007  11:05 AM  
Quote
Ad Astra - 14/5/2007  9:04 PM  Why wasn't this proposal written up the second the ESAS report came out?
 I showed something very close to “Direct” once during Sean O’Keefe and three times during Mike Griffin (twice before ESAS and one time after ESAS).  The idea was solid then and has only improved with all the additional refinements ...  I’m as confused as you are as to the problem with Direct at the high level...

It's all about agenda and staying on message at this level. Nothing can impact the agenda from outside or below HQ. Typically, either a frontal assault or cutting out the supports for the existing agenda are the only ways to tap shoulder to get the attention of such leadership. Or you can bide the time and await the self-destruction of said leadership, and/or the arrival of new leadership that desire a new direction.

Quote
Based on my take on these prior NASA-HQ meetings Sean’s boys didn’t like it because they were clearly going towards the all ELV approach.  From Mike’s boys they didn’t like it because they are pretty much Mars firsters so they wanted the largest vehicle that they could get (ie the Ares V)...

Mike can't bring off Ares I, let alone get Congressional approval for Ares V. Playing chicken and waiting for the other guy to blink isn't necessarily going to get a Mars rocket.

Quote
That was the genesis of the Jupiter-3 by the way.  I showed them how two Jupiter-1’s could be used as boosters putting a single launch Mars mission package of two total launches (ISRU+Return  followed by Crew) via chemical EDS at about 350mT IMLEO per launch.  If I said there response was sophomoric I would be generous.  

Typical of an overreaching agenda. If you don't have the votes, its "Plan B" or nothing. Looks like we are headed for "nothing" with Mike.

Point out he doesn't *need* to get Ares I. All he needs is the upgraded RSRB and CEV. If Ares 1 cancels after that, then he can push again for Ares V, and stretch out  Shuttle for another 5-10 years.

Title: RE: DIRECT v2.0
Post by: wannamoonbase on 05/16/2007 12:33 AM
Quote
RedSky - 10/5/2007  5:02 PM

To all involved in Direct 2... looks great.  But just a suggestion based on the intended audience: switch to American English spelling rather than UK English (e.g., maneuver for manoeuvre, etc.).  ;)

I disagree, the US could use more english and less of whatever it is that we use in this country.

As for v2.0 good to see persistence and evolution.  Perhaps this will happen yet.
Title: RE: DIRECT v2.0
Post by: CFE on 05/16/2007 02:58 AM
Maybe this has been addressed before, but I'm a little sketchy on understanding how Jupiter-232 can put 108mT into the reference orbit, on top of the 23mT partly-fueled EDS.  I understand that Ares V will have a capability to put ~130mT into a 120nmi circular orbit.  While it's not a totally fair comparison to say that Jupiter-232 puts 131mT into orbit (because the Jupiter reference orbit is 30x120nmi,) it still doesn't seem realistic that Jupiter-232 could achieve such performance.  Nevertheless, I'll run the numbers tomorrow and see if they're in the ballpark.

Still, Jupiter gives NASA an easier evolution path towards Ares V.  I like to note how the 5-segment version with stretched tank from the V1 proposal looks a lot like the "ESAS V1" CaLV, minus "expendable SSME's."  If NASA can overcome its opposition to RD-0120 engines, an 8.4m CaLV would still be possible as an evolution of Jupiter.

Finally,
Quote
wannamoonbase - 15/5/2007  6:33 PM
I disagree, the US could use more english and less of whatever it is that we use in this country.

Blame Noah Webster.
Title: Re: DIRECT v2.0
Post by: JIS on 05/16/2007 10:28 AM
Quote
SolarPowered - 15/5/2007  10:45 PM

Have you (the DIRECT team) looked at how much one could lift if they did a "maximally-evolved" Jupiter?  I.e., with regen RS-68's running at 106%, the best version of the J-2 now on the boards, maybe an extra engine or two, and the maximum stretch you can do to the core and upper stages while still using the existing facilities or minor improvements?  I'm wondering how that would compare with the Ares V, for the "I want the biggest BFR I can get" folks.

The only substantial difference between Jupiter and Ares V is the core size. The maximum size is dictated by 5seg SRBs and max diameter doable by Michoud factory (Saturn 1st stage diameter).
Title: Re: DIRECT v2.0
Post by: clongton on 05/16/2007 11:20 AM
Quote
JIS - 16/5/2007  6:28 AM

Quote
SolarPowered - 15/5/2007  10:45 PM

Have you (the DIRECT team) looked at how much one could lift if they did a "maximally-evolved" Jupiter?  I.e., with regen RS-68's running at 106%, the best version of the J-2 now on the boards, maybe an extra engine or two, and the maximum stretch you can do to the core and upper stages while still using the existing facilities or minor improvements?  I'm wondering how that would compare with the Ares V, for the "I want the biggest BFR I can get" folks.

The only substantial difference between Jupiter and Ares V is the core size. The maximum size is dictated by 5seg SRB’s and max diameter doable by Michoud factory (Saturn 1st stage diameter).
The 10m core is a mistake because, as Steve pointed out above, it takes too long to drain and makes the *effective* use of a second stage problematic. By staying with the 8.4m core, the Jupiter drains its core efficiently, leaving lots of real work for an upper stage to do, now unhindered by the massive weight of the empty stage below. The Ares-V carries far too much dead weight to altitude to get the most "bang for the buck" from its RS-68's. It's fighting itself all the way up. The 8.4m Jupiter, on the other hand, reaches its sweet spot fairly quickly, sheds its "dead weight" (the empty core) and then lets an upper stage, maximized for vacuum operations, finish the job in a very efficient manner. The fact that the Jupiter can be configured to exceed the capability of the Ares-V by a large margin is testimony to the wisdom of not re-inventing the wheel and rolling with what we already own; the 8.4m tank, 4-segment SRB's and the standard RS-68.

The Jupiter-254 is already more powerful than the Ares-V, and *IF* any engine enhancements were to ever come down the road, it would leave the Ares-V in the dust, Lunar and Martian dust that is. The Ares-V is the Jupiter-254's "baby brother".  :)
Title: Re: DIRECT v2.0
Post by: JIS on 05/16/2007 12:05 PM
Quote
clongton - 16/5/2007  12:20 PM
The Jupiter-254 is already more powerful than the Ares-V, and *IF* any engine enhancements were to ever come down the road, it would leave the Ares-V in the dust, Lunar and Martian dust that is. The Ares-V is the Jupiter-254's "baby brother".  :)

EDS using 4 J-2X engines could be OK for very large LEO masses, although it's not clear whether the engines can fit inside the interstage. But, it will be much worse for TLI injection. There is a good reason why Atlas V doesn't use two engines for centaur when launching to GEO orbit. I'm still not convinced at all that the Jupiter performance is realistic.
Title: Re: DIRECT v2.0
Post by: clongton on 05/16/2007 12:16 PM
Quote
JIS - 16/5/2007  8:05 AM

Quote
clongton - 16/5/2007  12:20 PM
The Jupiter-254 is already more powerful than the Ares-V, and *IF* any engine enhancements were to ever come down the road, it would leave the Ares-V in the dust, Lunar and Martian dust that is. The Ares-V is the Jupiter-254's "baby brother".  :)

EDS using 4 J-2X engines could be OK for very large LEO masses, although it's not clear whether the engines can fit inside the interstage. But, it will be much worse for TLI injection. There is a good reason why Atlas V doesn't use two engines for centaur when launching to GEO orbit. I'm still not convinced at all that the Jupiter performance is realistic.
4xJ2X do fit inside the interstage.
The performance numbers were extracted thru POST
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/16/2007 01:27 PM
If Direct 2.0 had been adopted form the start rather than what there is now, what kind of in service date would have been expected, how would going through Direct 1.0 first have added to that?
Title: RE: DIRECT v2.0
Post by: clongton on 05/16/2007 01:34 PM
Quote
PMN1 - 16/5/2007  9:27 AM

If Direct 2.0 had been adopted form the start rather than what there is now, what kind of in service date would have been expected, how would going through Direct 1.0 first have added to that?
First test article could have flown within 6 months of Shuttle stand down, first manned Orion within 12 months.
Title: Re: DIRECT v2.0
Post by: meiza on 05/16/2007 01:47 PM
Did you test with more nozzle extensions in the RS-68 engines? (Similar pressure as they have now). Sutton says roughly this about overexpansion:
Where p2 is nozzle exit pressure and p3 is ambient pressure:
1) when p32) when p3 is slightly bigger than p2 (p2>0.4p3), still full flow.
3) when external pressure is high, nozzle has flow separation (bad!)

As the Vulcain 2 has a chamber pressure of 116 bar and area ratio of 61 and is lit at the sea level AND flies in a Direct-like configuration, one should wonder would doing a similar nozzle expansion to the RS-68 96 improve performance significantly, as it currently runs at chamber pressure of 96 bars and area ratio of only 22. RS-68 is currently optimized for a first stage use but in the Direct application the majority of low altitude thrust would come from the solids. And indeed it seems Ariane 5 optimized to a high expansion, low thrust at sea level configuration. Though it flies GEO missions mainly.

RS-68 current
Thrust: sl 2.9 MN, vac 3.3 MN , about 14% more at altitude
Vulcain 2 current
Thrust: sl 0.94 MN, vac 1.3 MN, about 40% more at altitude
RS-68 extended
would have lower than current at sea level but better at altitude

A development program for an ablative nozzle's extension in the relatively cool expanded region shouldn't be as expensive as making some other engine work, say, with turbopumps or gas generators...

Of course, as an analysis side path only, I understand you want to stay as strictly off-the-shelf in the hardware department as possible in the Core Direct Philosophy.
Title: Re: DIRECT v2.0
Post by: clongton on 05/16/2007 01:54 PM
Quote
meiza - 16/5/2007  9:47 AM

Did you test with more nozzle extensions in the RS-68 engines?
We did test with several possible configurations, to ensure that the base design provided the best path to possible growth options. However, as you have observed, the proposal uses stock performance numbers from existing flight-tested hardware. Enhansed performance designs were deliberately left out of the proposal, but the options do exist.
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/16/2007 01:57 PM
Would what is being proposed have been possible technology-wise after the Challenger accident?
Title: RE: DIRECT v2.0
Post by: clongton on 05/16/2007 02:03 PM
Quote
PMN1 - 16/5/2007  9:57 AM

Would what is being proposed have been possible technology-wise after the Challenger accident?
RS-68 wasn't developed until 1998. But there was a similar proposal presented from MSFC that used the SSME instead.
Title: Re: DIRECT v2.0
Post by: JIS on 05/16/2007 02:06 PM
Quote
meiza - 16/5/2007  2:47 PM

As the Vulcain 2 has a chamber pressure of 116 bar and area ratio of 61 and is lit at the sea level AND flies in a Direct-like configuration, one should wonder would doing a similar nozzle expansion to the RS-68 96 improve performance significantly, as it currently runs at chamber pressure of 96 bars and area ratio of only 22.

Vulcain 2 is ducting generator gas back to the main nozzle unlike RS-68.
Title: Re: DIRECT v2.0
Post by: JIS on 05/16/2007 02:08 PM
Quote
clongton - 16/5/2007  1:16 PM

The performance numbers were extracted thru POST
The output can't be better than input.
Title: Re: DIRECT v2.0
Post by: clongton on 05/16/2007 02:20 PM
Quote
JIS - 16/5/2007  10:08 AM

Quote
clongton - 16/5/2007  1:16 PM

The performance numbers were extracted thru POST
The output can't be better than input.
You're quoting me  :)
That's precisely why we have asked for an in-depth critique from this community. Some of you have access to POST, and we would hope that would spur independent analysis of our numbers. If you have access, PM us (me, Steve, Ross). We want to be right, not famous. We think we're right. But numbers don't lie, and independent numbers are better yet. If you have independent analysis capability, step into our office. We want to talk with you. We need, and appriciate valid critics.
Title: Re: DIRECT v2.0
Post by: jongoff on 05/16/2007 02:25 PM
JIS,
Quote
Vulcain 2 is ducting generator gas back to the main nozzle unlike RS-68.

But that has nothing to do with the expansion ratio you can achieve at takeoff.  The gas ducting
only gets you back a little potentially wasted performance, and helps cool part of the extension.
Even without gas ducting back into the engine, you probably could make an RS-68 extended
nozzle version without much trouble.  You might not get every last second available (as that gas
ducting is probably worth at least 1-2s), but you're going to greatly increase the mission average
Isp.  The main reason this wasn't done already has been already been discussed--RS-68 had to
be optimized for a lower altitude because in some configurations there are no strapons helping
out, so all the thrust comes from the RS-68.   Every other large LOX/LH2 vehicle that uses large
strapons has gone with a higher-altitude expansion ratio on their LOX/LH2 engine.  There's no
reason the same couldn't be done for RS-68.

~Jon
Title: Re: DIRECT v2.0
Post by: JIS on 05/16/2007 03:50 PM
Quote
jongoff - 16/5/2007  3:25 PM

JIS,
Quote
Vulcain 2 is ducting generator gas back to the main nozzle unlike RS-68.

But that has nothing to do with the expansion ratio you can achieve at takeoff.
~Jon

I think it has some effect. The pressure in the nozzle downstream of the generator gas inlet is increased compared to “classic” nozzle.
Title: Re: DIRECT v2.0
Post by: JIS on 05/16/2007 03:53 PM
Quote
clongton - 16/5/2007  3:20 PM

Quote
JIS - 16/5/2007  10:08 AM

Quote
clongton - 16/5/2007  1:16 PM

The performance numbers were extracted thru POST
The output can't be better than input.
You're quoting me  :)
That's precisely why we have asked for an in-depth critique from this community. Some of you have access to POST, and we would hope that would spur independent analysis of our numbers. If you have access, PM us (me, Steve, Ross). We want to be right, not famous. We think we're right. But numbers don't lie, and independent numbers are better yet. If you have independent analysis capability, step into our office. We want to talk with you. We need, and appriciate valid critics.

Glad to help. However, the only POST I'm using is the British one :-)
Title: RE: DIRECT v2.0
Post by: Lee Jay on 05/16/2007 04:23 PM
Quote
CFE - 15/5/2007  8:58 PM
Maybe this has been addressed before, but I'm a little sketchy on understanding how Jupiter-232 can put 108mT into the reference orbit, on top of the 23mT partly-fueled EDS.  I understand that Ares V will have a capability to put ~130mT into a 120nmi circular orbit.  While it's not a totally fair comparison to say that Jupiter-232 puts 131mT into orbit (because the Jupiter reference orbit is 30x120nmi,) it still doesn't seem realistic that Jupiter-232 could achieve such performance.  Nevertheless, I'll run the numbers tomorrow and see if they're in the ballpark.

According to Wikipedia, STS-121 had mass to orbit of 121,092kg.  That's to the ISS orbit.  The RS-68s have lower ISP than the SSMEs, but higher thrust.  Given this information as a source of comparison rather than Ares V, and the addition of the EDS, does 131mT still seem unreasonable to the 28.5° 30x120 orbit?  I'm asking because I don't know.

Lee Jay
Title: Re: DIRECT v2.0
Post by: jongoff on 05/16/2007 05:26 PM
JIS,
Quote
I think it has some effect. The pressure in the nozzle downstream of the generator gas inlet is increased compared to “classic” nozzle.

Not by very much.  Gas generators typically only run a couple percent of the main flow, so I'd be surprised if it upped the nozzle pressure at outlet by more than a few percent.  Not enough to call into question that you could get a better expansion ratio on the RS-68 if you were designing a new nozzle extension intentionally for this use.  Heck, ATK makes those nozzle extensions, I'm sure they'd be glad to get paid to develop it if DIRECT went that way...

~Jon
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/16/2007 05:31 PM
Quote
Alpha Control - 10/5/2007  11:36 PM

When I was growing up, the accent was always on the 2nd syllable, which of course provided endless mirth for school age boys.


Who in the UK remember the Spitting Image sketch with the newscaster asking why the pronunciation had suddenly changed (IIRC Voyager was doing its flyby)

'Is it to save potential embarrassment when saying 'probing Uranus or the rings around Uranus'?'

 :)
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/16/2007 05:33 PM
Quote
clongton - 16/5/2007  9:03 AM

Quote
PMN1 - 16/5/2007  9:57 AM

Would what is being proposed have been possible technology-wise after the Challenger accident?
RS-68 wasn't developed until 1998. But there was a similar proposal presented from MSFC that used the SSME instead.

In-line payload or side mounted - the ones I've seen on the on Astronatix site seem to be all side mounted payload.
Title: RE: DIRECT v2.0
Post by: clongton on 05/16/2007 05:52 PM
Quote
PMN1 - 16/5/2007  1:33 PM

Quote
clongton - 16/5/2007  9:03 AM

Quote
PMN1 - 16/5/2007  9:57 AM

Would what is being proposed have been possible technology-wise after the Challenger accident?
RS-68 wasn't developed until 1998. But there was a similar proposal presented from MSFC that used the SSME instead.

In-line payload or side mounted - the ones I've seen on the on Astronatix site seem to be all side mounted payload.
Both were in the mix. The side-mounted was designated Shuttle-C and was favored because it was identical to the mounting of the orbiter. The inline was identified as being more efficient but more costly because of the changes needed to the ET (thrust structure, tank walls, etc). The effort was to do it as cheaply as possible, that's why the side-mount was favored; almost no changes to the sts stack at all.

In the end neither was adopted because Congress was willing to fund fixing the SRB's but not willing to fund replacing the orbiter.

Incidentally, this was one of the first serious efforts to separate crew from cargo, another one of the debates that has been raging since the CAIB Report came out. There is also a discussion thread on NSF about this as well. The cargo cannister, side or top mount, was not recoverable. Both versions were entirely ELV's.
Title: Re: DIRECT v2.0
Post by: Ad Astra on 05/16/2007 06:16 PM
Quote
SMetch - 15/5/2007  11:05 AM

Quote
Ad Astra - 14/5/2007  9:04 PM

Why wasn't this proposal written up the second the ESAS report came out? What was the delay? What will you do if Dr Stanley comes on here and slaps this out of the ballpark like Direct 1? Will there then be a Direct 3, and 4 and 5? Are you banking on a Democrat win so as to be an alternative cheaper solution when Ares is cancelled due to money?

Lots of questions here, but I am impressed with your presentation. On face value it looks a lot more obvious and sensible.

I showed something very close to “Direct” once during Sean O’Keefe and three times during Mike Griffin (twice before ESAS and one time after ESAS).  The idea was solid then and has only improved with all the additional refinements in launch infrastructure modification, programmatic and configurational work others have added to it since then.

From the grass roots level to just below the NASA Executive level “Direct” is very popular (better than 2/3 roughly).  I’m as confused as you are as to the problem with Direct at the high level.

Based on my take on these prior NASA-HQ meetings Sean’s boys didn’t like it because they were clearly going towards the all ELV approach.  From Mike’s boys they didn’t like it because they are pretty much Mars firsters so they wanted the largest vehicle that they could get (ie the Ares V).

That was the genesis of the Jupiter-3 by the way.  I showed them how two Jupiter-1’s could be used as boosters putting a single launch Mars mission package of two total launches (ISRU+Return  followed by Crew) via chemical EDS at about 350mT IMLEO per launch.  If I said there response was sophomoric I would be generous.  The loading dynamics on the Jupiter-3 is as about as close to three rockets going up independently as you could hope for.

The key issue is the pitch and roll maneuver prior to entering the gravity turn.  That and the infrastructure issues at KSC but I generally envision the launches from sea for this bad boy.  KSC will be over 50 years old and who knows how long before a Hurricane with its name on it takes it out.  The Jupiter-3’s center engines basically feed off the out Jupiter-1’s tank draining them at a similar rate as the Jupiter-242 does allowing for a near optimal second stage switching the center engines prior to staging to the center 2nd stage tank.

Having the heavier lifter use a common core booster with the lower end family members is a big advantage from a fixed cost stand point.

Again the Jupiter-3 may never happen and if it did it would be +25 years from now.  Lunar staging of the Jupiter-2 may be the actual way we go to Mars.  But part of me hopes that the future space program would actually need a vehicle capable of +350mT.


Thanks for your answer and good luck.
Title: Re: DIRECT v2.0
Post by: luke strawwalker on 05/16/2007 08:28 PM
Hi!  I've been reading the Direct goes Live thread and am up to about page 95, and this was asked around page 75 but not answered
(so far) though I'm still wading through it so here goes:

If the Ares I is underpowered due to the switch from the SSME upper stage to the J2X, requiring the switch to the 5 seg RSRB to make up
the difference, then it would seem that what would be the quickest fix would be a more powerful second stage motor than the J2X.  

Would it be possible to to put an RS-68 in the second stage instead of the J2X?  I'm sure this has been thought of by somebody but I don't
have enough information to know why it wouldn't be feasible.  Seems like from the discussion that the RS-68 is a lot closer to the performance
of the SSME than the J2X is.  I know there would probably be issues with airstarting an RS-68 or the lower ISP rating making it not 'optimal'
for use in an upperstage but if it got you the added power you need to switch back to the 4 seg RSRB then the problems might be more
'doable'.  I was going to add that developing it could allow it to be used for the EDS instead of the J2x but I bet it's not designed to be restarted
or for long cold soaks in orbit.  Oh well....

I'd really like to know why my idea sucks though :)  Yall take it easy!  OL JR :)
Title: Re: DIRECT v2.0
Post by: Jim on 05/16/2007 08:31 PM
Quote
luke strawwalker - 16/5/2007  4:28 PM
  I know there would probably be issues with airstarting an RS-68 or the lower ISP rating making it not 'optimal'
for use in an upperstage
 but I bet it's not designed to be restarted
or for long cold soaks in orbit.  Oh well....


you are correct
Title: Re: DIRECT v2.0
Post by: clongton on 05/16/2007 08:43 PM
Quote
luke strawwalker - 16/5/2007  4:28 PM
I know there would probably be issues with airstarting an RS-68
The idea doesn't suck. The RS-68 would make an awesome upper stage engine except for the air-start requirement. The Direct v2 team seriously considered it. It could certainly be done, but would require a major design effort on the part of PWR and would be very expensive.

Don't simply dismiss the concept. If we can get thru this transition from LEO on the Shuttle to the moon on the Jupiter in lieu of the Ares, the possibility could exist that funding could be made available for this. But if we end up staying the whole Ares route, NASA will be too poor to pay attention.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/16/2007 08:44 PM
Luke, the issue with a different engine to J-2X is to make Ares-I operational fast enough to close the gap after Shuttle retires.   When SSME was decided against, the next largest air-startable hi-efficiency (Isp) engine available was the J-2S - parts of which were already in development use on the Linear Aerospike XRS-2200 program which was going to power the X-33.

The J-2S already exists, and was in a position to be enhanced in performance above it's old Apollo specifications, so it was chosen.

NASA had the option to built something all-new, with higher performance than the J-2X, but the cost and the schedule delays made it a bad option given the targets they were trying to achieve.

Ross.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/16/2007 08:44 PM
Steve and Chuck, thanks for your answers to my question about how much an evolved Jupiter might be able to lift.  I see that it could be extended quite a lot, if need be.

On the other hand, I've since been thinking about the "if need be" part, and it seems to me that building a Mars program around your current proposal, without doing any extensions, in fact makes a great deal of sense.  Suppose, for example, you want to assemble a 500 mT Mars mission.  Using currently-existing ELVs, which max out in the neighborhood of 20-25 mT, you would need 20 to 25 launches to lift that 500 mT.  In my opinion, that is an unworkable concept.

But, if we're talking Ares V and Jupiter, it comes down to Ares V requiring four launches, and an unevolved Jupiter requiring five launches.  There's really not much point in a whole deveopment program, whether it be Area V or an evolved Jupiter, to save one lanuch for each Mars mission.  You'd be much better off spending the money on more and bigger moon and Mars missions.
Title: Re: DIRECT v2.0
Post by: clongton on 05/16/2007 08:54 PM
Quote
SolarPowered - 16/5/2007  4:44 PM

Steve and Chuck, thanks for your answers to my question about how much an evolved Jupiter might be able to lift.  I see that it could be extended quite a lot, if need be.

On the other hand, I've since been thinking about the "if need be" part, and it seems to me that building a Mars program around your current proposal, without doing any extensions, in fact makes a great deal of sense.  Suppose, for example, you want to assemble a 500 mT Mars mission.  Using currently-existing ELVs, which max out in the neighborhood of 20-25 mT, you would need 20 to 25 launches to lift that 500 mT.  In my opinion, that is an unworkable concept.

But, if we're talking Ares V and Jupiter, it comes down to Ares V requiring four launches, and an unevolved Jupiter requiring five launches.  There's really not much point in a whole deveopment program, whether it be Area V or an evolved Jupiter, to save one lanuch for each Mars mission.  You'd be much better off spending the money on more and bigger moon and Mars missions.
Well thought out consideration. You are correct in your assesment with a single correction. The EELV's are CURRENTLY capable of 20-25 mT lift, but planned variants will be capable of up to 45-50 mT of lift capability. But that doesn't change the basic correctness of your observation.

We can go to Mars with the Jupiter as proposed. IF a larger variant were needed, it would not be a big stretch to provide it. Family configurations, not discussed in the proposal, exceed 250mT of lift. But the question becomes one of economics. Such launch vehicles require a valid need to justify their development costs. That essentially boils down to launch rate, and then you're trading 2-3 Jupiter 232's off on 1-2 Jupiter 254's. Is it justifiable? Maybe - maybe not. It depends on the chosen architecture and future developments. It's just comforting to know that the Jupiter has this growth capacity designed into it from the very beginning, while Ares-V begins life already maxed out.
Title: Re: DIRECT v2.0
Post by: Scotty on 05/16/2007 09:05 PM
There is another engine that could be used on the upper stage, that is the French Vulcain II.
It is a 300,000 pound thrust class engine with a vacuum isp of 434.
But, it is also a ground start engine.
It likely could be made into a air start capable engine, but at a cost of time and money.

A better solution would be to use two base line, Apollo era J2 engines on the upper stage, with a 4 segment booster.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/16/2007 09:25 PM
Quote
PMN1 - 16/5/2007  1:33 PM

Quote
clongton - 16/5/2007  9:03 AM

Quote
PMN1 - 16/5/2007  9:57 AM

Would what is being proposed have been possible technology-wise after the Challenger accident?
RS-68 wasn't developed until 1998. But there was a similar proposal presented from MSFC that used the SSME instead.

In-line payload or side mounted - the ones I've seen on the on Astronatix site seem to be all side mounted payload.

Following the 1986 loss of Challenger, the "Shuttle-C" concept gained a lot of momentum because it retained use of the RSS at the pad, and was completely compatible with Shuttle payloads, yet offered an unmanned launch solution.   At the time they still needed to launch a lot of satellites which had been designed to fly on Shuttle and it was a reasonable solution to that problem.

Anyhow, Shuttle-C was not the only proposal considered around 1986.   There was an in-line variant, with an 8.4m diameter payload shroud located on top of a modified External Tank. With three SSME's under the core, it offered approximately 75mT performance to LEO.   This configuration was actually assessed in the ESAS Report too - where they confirmed the same basic performance, but missed analysing its performance with an EDS Upper Stage.

Titan-IV was ultimately developed, and flew all those payloads and neither Shuttle-C nor the in-line version were developed.

The same basic concept was again proposed in 1991 as the National Launch System or NLS (image below, Credit: Astronautix.com).   It was a joint program between NASA and USAF.   Powered by standard SRB's, it had four new main engines called Space Transportation Main Engine (STME) which had 550,000lb vac thrust and 431s vac Isp.   While I can't get a specific reference, the STME appears to be a disposable variant of SSME.

Two RS-68's produce as much thrust as three SSME's, and offer similar efficiency to the STME, albeit slightly lower.   Because that engine exists already and is flight-ready, we chosen to use the RS-68 rather than have to develop a new engine.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/16/2007 09:31 PM
Quote
Scotty - 16/5/2007  5:05 PM

There is another engine that could be used on the upper stage, that is the French Vulcain II.
It is a 300,000 pound thrust class engine with a vacuum isp of 434.
But, it is also a ground start engine.
It likely could be made into a air start capable engine, but at a cost of time and money.

A better solution would be to use two base line, Apollo era J2 engines on the upper stage, with a 4 segment booster.

Even 434s vac Isp isn't as good as 448s.   The lower efficiency requires more propellant to be lifted to achieve the TLI burn, so I'm not sure there are any advantages to be had anywhere there.

Unless there is a major technical hitch to achieving 448s Isp, the J-2X is the way to go IMHO.

I wish the RL-60 was deployable now, because a cluster of 5 of those with 470s Isp would be an interesting alternative.   But it isn't.   Ho hum.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/16/2007 09:57 PM
Quote
meiza - 16/5/2007  9:47 AM

Did you test with more nozzle extensions in the RS-68 engines?

We had it in-work for v1.0 when the whole Stanley thing happened.   We have since received some hard data back, and actually have complete independent validation of the original Regen concept.   Oh well.

With no doubts at all, the current ablative nozzle could be redesigned to optimize for high altitude use, optimizing performance so it still avoids flow separation while at Sea Level.

This is still a "growth option" for Jupiter and promises a few extra % of performance.

There are a number of relatively simple options available to increase Jupiter performance further, but which we have deliberately removed from the critical path to enable the fastest possible deployment and the minimum number of risk elements.   This also helps delete all the points of criticism which were taken advantage of by opponents.

Operating the engine at 106%, as NASA proposes for Ares-V, offers additional performance in the region of 7mT extra to LEO per flight on the Jupiter-232.

Use of a regen nozzle (which should automatically include optimization for high altitude use) is still possible too, offering about 5mT of additional performance on the J-232 too.

And we have planned the DIRECT to use a "heavy" core like the original Shuttle ET.   We would expect an ongoing improvements program would result in a Light Weight Tank (LWT) and perhaps a Super Light Weight Tank (SLWT) becoming available in the future too, again offering greater performance.

If all these design changes were to be included, 55mT for the J-120 should be achievable, and 120mT should be possible for the J-232.

Ross.
Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/16/2007 10:40 PM
It seems like with v.2 you have done everything to be conservative (with the possible exception of the EDS, and even that is simply a conservative version of a Centaur rather than an ESAS EDS). You have chosen the basic J2, and the basic RS68 with no regen, no 106% power level, and no nozzle changes. You have chosen the old ET design rather than the SLWET. You have chosen fairly large margins apparently everywhere.
This all seems to be an effort to get DIRECT accepted- but it seems that the problem is not a technical one, it is a political one.

Is there some way that DIRECT can be 'peer reviewed' by somebody whose opinion is influencial? I think that this would be a crucial step.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/16/2007 11:02 PM
Quote
Kaputnik - 16/5/2007  3:40 PM

It seems like with v.2 you have done everything to be conservative (with the possible exception of the EDS, and even that is simply a conservative version of a Centaur rather than an ESAS EDS). You have chosen the basic J2, and the basic RS68 with no regen, no 106% power level, and no nozzle changes. You have chosen the old ET design rather than the SLWET. You have chosen fairly large margins apparently everywhere.
This all seems to be an effort to get DIRECT accepted- but it seems that the problem is not a technical one, it is a political one.

Is there some way that DIRECT can be 'peer reviewed' by somebody whose opinion is influencial? I think that this would be a crucial step.
As an outsider looking in, but who has many times been in a similar position in my own line of work, my opinion is that the "powers that be" have made up their minds about what they are going to do, and there is no power on earth or in Heaven that will persuade them otherwise.

The way this insanity works is that even if they encounter insurmountable obstacles to accomplishing their plans, they will change the objectives rather than abandon flawed plans.

There is, however, a substantial chance that there will be a change in leadership at NASA.  If at that time a well-developed DIRECT plan exists (which it does), and it is widely accepted within the lower ranks of NASA, there is a substantial chance that it will be adopted at that point in time.


(Edit to add: I'm really, really hoping that someone will post, telling me that I'm wrong, and that there is reason to hope that the current management might change direction.)
Title: Re: DIRECT v2.0
Post by: wingod on 05/16/2007 11:07 PM
Quote
kraisee - 16/5/2007  3:44 PM

Luke, the issue with a different engine to J-2X is to make Ares-I operational fast enough to close the gap after Shuttle retires.   When SSME was decided against, the next largest air-startable hi-efficiency (Isp) engine available was the J-2S - parts of which were already in development use on the Linear Aerospike XRS-2200 program which was going to power the X-33.

The J-2S already exists, and was in a position to be enhanced in performance above it's old Apollo specifications, so it was chosen.

NASA had the option to built something all-new, with higher performance than the J-2X, but the cost and the schedule delays made it a bad option given the targets they were trying to achieve.

Ross.

The only part of the J2 used on the X-33 aerospike was an unmodified turbopump.

Title: Re: DIRECT v2.0
Post by: Jim on 05/16/2007 11:25 PM
Quote
clongton - 16/5/2007  4:43 PM

Quote
luke strawwalker - 16/5/2007  4:28 PM
I know there would probably be issues with airstarting an RS-68
The idea doesn't suck. The RS-68 would make an awesome upper stage engine except for the air-start requirement. The Direct v2 team seriously considered it. It could certainly be done, but would require a major design effort on the part of PWR and would be very expensive.

.

restart would be even harder
Title: Re: DIRECT v2.0
Post by: CFE on 05/17/2007 01:49 AM
Quote
wingod - 16/5/2007  5:07 PM

Quote
kraisee - 16/5/2007  3:44 PM

Luke, the issue with a different engine to J-2X is to make Ares-I operational fast enough to close the gap after Shuttle retires.   When SSME was decided against, the next largest air-startable hi-efficiency (Isp) engine available was the J-2S - parts of which were already in development use on the Linear Aerospike XRS-2200 program which was going to power the X-33.

The J-2S already exists, and was in a position to be enhanced in performance above it's old Apollo specifications, so it was chosen.

NASA had the option to built something all-new, with higher performance than the J-2X, but the cost and the schedule delays made it a bad option given the targets they were trying to achieve.

Ross.

The only part of the J2 used on the X-33 aerospike was an unmodified turbopump.


Was there any modification of the J-2S turbopump when it was used for the XRS-2200?  I had read that, in regards to the J-2XD vs. the J-2X, the J-2XD will use the J-2S turbopumps while the final J-2X will use the XRS-2200 turbopump.  I thought the two were the same, but apparently the definitive J-2X will produce 14klbf more thrust than J-2XD.

Nevertheless, J-2X represents a large development plan, as the thrust chamber and nozzle will essentially be new hardware.  I'd go with the lower-Isp Vulcain 2, but only if I was certain that modifying it for air-start was cheaper than re-development of the J-2X.

While we're on the subject of adopting foreign-developed engines, I wanted to mention that the RD-0120 was  essentially the STME in terms of its specs.  I think that if NASA allowed for its use in VSE (assuming the Russians can still build it,) it would solve a lot of problems caused by the demise of "expendable SSME."
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/17/2007 01:57 AM
What is you're game plan for promoting direct 2.0 ?   There are many ways to approach it.   There are a number of groups that you can target, including personel at NASA, congressional members, retired astronauts, and even news organizations.  You can go directly to the decision makers or try to build support from proffesionals in the field  Are you going to try to arrange in person presentations, or do mailers or ?  
It might make sense to get some professional advice  on putting together a presentation or a marketing plan.  THat will cost you some dough of course.  

 When dealing with anyone at NASA they are going to want to know the credentials of those who are asking for their time and consideration.
A plan put together by model builders  might not go over to well.   If put together by people with serious aerospace engineering experience (and degrees) would have a better chance to get looked at.  
Title: Re: DIRECT v2.0
Post by: clongton on 05/17/2007 02:36 AM
Quote
veedriver22 - 16/5/2007  9:57 PM

A plan put together by model builders  might not go over to well.   If put together by people with serious aerospace engineering experience (and degrees) would have a better chance to get looked at.  
When a book or research volume is published, it is the result of collaboration between two professional forces:
1. The author(s), who are the heart and soul of the work. They are the source of the content of the work.
2. The editors, who are the ones who arrange and critique the format of the work, but not its contents.
It is the same with the Direct proposal. The authors are the scientists and design engineers who work for NASA, its Field Centers and its Contractors. It is THEY who are the technical brilliance and source of this work, not us.
We are editors, and, from the very beginning, went out of our way to make it crystal clear that the work was not ours, but theirs. They did the hard work, the analysis and tradeoff studies. It is they who tell us thru their work that "this would work, but if you did this, that would work also, and here is the difference". The brilliance of this work is properly credited to the design engineers and scientists at NASA, its Field Centers and Contractors, not us. We have been privileged to have a small part in arranging their work for presentation to you, the space community, to the NASA upper management and to the Congressional Committee members with responsibility for Space Policy oversight.

This work actually was, as you say, "put together by people with serious aerospace engineering experience (and degrees)". I would also add that just because we edited the body of the work, rather than authored it, it does not follow (as you have erroneously implied) that we ourselves are without "serious aerospace engineering experience (and degrees)". Some of us have been doing this kind of thing for a very long time.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/17/2007 03:03 AM
I am sorry if that is how that came across.   I did not mean to imply anything about anyone involved in Direct.  The work you guys are doing is tremendous.   My intent was to point out how certain individuals (such as NASA higher ups), might see it.   Sorry if I insulted anyone, that was not my intent.  Its just something I thought might be worth thinking about.    I really would like to know what your sales plan looks like if its something you can share.
Title: Re: DIRECT v2.0
Post by: clongton on 05/17/2007 03:09 AM
Quote
veedriver22 - 16/5/2007  11:03 PM

I am sorry if that is how that came across.   I did not mean to imply anything about anyone involved in Direct.  The work you guys are doing is tremendous.   My intent was to point out how certain individuals (such as NASA higher ups), might see it.   Sorry if I insulted anyone, that was not my intent.
Not to worry. No danger of that. A couple of us are already very well known to the Administrator and his staff.
Title: Re: DIRECT v2.0
Post by: Steve G on 05/17/2007 05:47 AM
I assume that the upper management and even the administrator must be aware that this proposal exists and may even have read it.   If I was Griffin, I’d consider this a low level mutiny and act accordingly to get the team focused on the Ares program.

Has anyone heard of any rumblings from the top?
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/17/2007 07:47 AM
Ah yes, there were in-line varients, i've even got a print out from Astronautix of the one with a 10m shroud in a file I was lookig at yesterday....memory must be going.

Title: Re: DIRECT v2.0
Post by: PMN1 on 05/17/2007 07:50 AM
Not to worry. No danger of that. A couple of us are already very well known to the Administrator and his staff.


Anyone woken up to find a horses head next to them????

 :)
Title: Re: DIRECT v2.0
Post by: JIS on 05/17/2007 09:01 AM
Quote
kraisee - 16/5/2007  9:44 PM

The J-2S already exists, and was in a position to be enhanced in performance above it's old Apollo specifications, so it was chosen.


J-2X is not based on J-2S but J-2. J-2S is a dead end. Only the turbopumps are used for J-2XD but will be superseeded with new ones for J-2X.
Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/17/2007 10:49 AM
Quote
CFE - 17/5/2007  2:49 AM
While we're on the subject of adopting foreign-developed engines, I wanted to mention that the RD-0120 was  essentially the STME in terms of its specs.  I think that if NASA allowed for its use in VSE (assuming the Russians can still build it,) it would solve a lot of problems caused by the demise of "expendable SSME."

I mentioned this already in the first DIRECT thread. The RD-0120 could have been the air-startable, disposable SSME that NASA wanted back in the ESAS. If they used it, the stick would still have 4-segments, and the Ares-V would look a whole lot better too.
There are apparently some RD0120s mothballed at Baikonur but I have had no luck in unearthing informatin about how many, their condition, and whether anybody is still around to operate them.
Very sad, really- they must have been great engines.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/17/2007 05:24 PM
So what is the game plan from here? ...... or is that classified?
Title: Re: DIRECT v2.0
Post by: sandrot on 05/17/2007 09:05 PM
How many RD-0120 flown as of today?
Title: Re: DIRECT v2.0
Post by: NotGncDude on 05/17/2007 10:01 PM
8? Two Energia flights?
Title: Re: DIRECT v2.0
Post by: CFE on 05/18/2007 04:34 AM
AFAIK, it's been eight RD-0120's on both Energia flights.  I realize now that this engine is closer in performance to "expendable SSME" than STME.  The regen-cooled RS-68R from DIRECT V1 has very similar performance to STME.  I had wanted to examine alternative engine choices because of my concerns that Jupiter would fall short of its performance targets.  Fortunately, I think my former fears were unfounded.

I've done some rough calcs to verify the performance predicted for Jupiter-232.  While I'm currently looking for some validation of my work, I have confidence that Jupiter-232 can fill the Ares V role in the "1.5 launch" scenario.  Truth be told, Ares V is really overkill for this mission profile.

I'm concerned that the performance figures given in DIRECT V2 reflect a 30x120nmi orbit.  DIRECT's critics are really going to latch onto this.  I think it's best to give all performance figures in terms of a circular assembly orbit (such as the 120nmi orbit for Ares V.)  My concerns temporarily turned me into a "Doubting Thomas," hence my attempts to verify the performance numbers.
Title: Re: DIRECT v2.0
Post by: Thomas ESA on 05/18/2007 08:55 AM
Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.
Title: Re: DIRECT v2.0
Post by: Crispy on 05/18/2007 10:00 AM
Quote
Thomas ESA - 18/5/2007  9:55 AM

Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.

Absolutely key point.
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 11:58 AM
Quote
Thomas ESA - 18/5/2007  4:55 AM

Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.
Tom (and everyone):
Please provide a list of what you see as key weaknesses.
Title: Re: DIRECT v2.0
Post by: kevin-rf on 05/18/2007 01:08 PM
Quote
clongton - 18/5/2007  6:58 AM
Tom (and everyone):
Please provide a list of what you see as key weaknesses.

NIH (Not Invented Here, by upper Nasa management)
Title: Re: DIRECT v2.0
Post by: marsavian on 05/18/2007 03:52 PM
Clongton,

Did you consider a Jupiter-110 with one centerline RS-68 purely for the ISS missions as the baseline Jupiter-120 looks overpowered for the job ?
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 04:11 PM
Quote
marsavian - 18/5/2007  11:52 AM

Clongton,
Did you consider a Jupiter-110 with one centerline RS-68 purely for the ISS missions as the baseline Jupiter-120 looks overpowered for the job ?
We did. On page 8 of this thread, Steve G asked a very similar question.
My answer, in part, is pasted below. See page 8 for the entire answer.
--------
Quote
Steve G - 13/5/2007  12:00 AM

This is not a suggestion.  I’m just curious. What would be;
a) The performance of a 2 x standard SRB’s and a single RS-68 assuming the tank size would have a narrower diameter but the same height to be launch pad compatible.
We actually worked that out, while keeping the ET diameter unchanged. It would be a Jupiter 110. It would be a direct competitor with the ELV fleet, so we decided not to go there. What Direct wants to do is to compliment and go beyond the ELV fleet, not compete with it.

At the end of the proposal and in this thread, we have alluded to the upcoming 2007 AIAA paper. In it are five driving imperatives which ultimately determined the design parameters of the Jupiter Launch Vehicle family.

From the paper (caution: WIP):

Imperative #3: Do not duplicate the lift capacity that is already available in the existing launch vehicles of the Evolved Expendable Launch Vehicle fleet.

-- more back on page 8 --
Title: Re: DIRECT v2.0
Post by: marsavian on 05/18/2007 04:19 PM
Quote
clongton - 18/5/2007  11:11 AM

Quote
marsavian - 18/5/2007  11:52 AM

Clongton,
Did you consider a Jupiter-110 with one centerline RS-68 purely for the ISS missions as the baseline Jupiter-120 looks overpowered for the job ?
We did. On page 8 of this thread, Steve G asked a very similar question.
My answer, in part, is pasted below. See page 8 for the entire answer.
--------
Quote
Steve G - 13/5/2007  12:00 AM

This is not a suggestion.  I’m just curious. What would be;
a) The performance of a 2 x standard SRB’s and a single RS-68 assuming the tank size would have a narrower diameter but the same height to be launch pad compatible.
We actually worked that out, while keeping the ET diameter unchanged. It would be a Jupiter 110. It would be a direct competitor with the ELV fleet, so we decided not to go there. What Direct wants to do is to compliment and go beyond the ELV fleet, not compete with it.

At the end of the proposal and in this thread, we have alluded to the upcoming 2007 AIAA paper. In it are five driving imperatives which ultimately determined the design parameters of the Jupiter Launch Vehicle family.

From the paper (caution: WIP):

Imperative #3: Do not duplicate the lift capacity that is already available in the existing launch vehicles of the Evolved Expendable Launch Vehicle fleet.

-- more back on page 8 --


Surely the need must be for the most cost-effective SDLV solutions to *all* of NASA's needs whether it duplicates EELV capabilities or not ? If a Jupiter-110 is the most cost-effective solution for launching a CEV to and fro from the ISS than surely it should be included in the proposal as a man-rated EELV in that category is not on the cards for anyone in the forseeable future and even less likely to be adopted by NASA. It's also simpler too than the 120 which might appeal to the Ares I crowd ;-). You are after all trying to convince NASA and catering to their current mindset would help to sell DIRECT.
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 04:47 PM
Quote
marsavian - 18/5/2007  11:52 AM

clongton,
Did you consider a Jupiter-110 with one centerline RS-68 purely for the ISS missions as the baseline Jupiter-120 looks overpowered for the job ?

We did (additional comments edited out - see above)

Quote
Surely the need must be for the most cost-effective SDLV solutions to *all* of NASA's needs whether it duplicates EELV capabilities or not. If a Jupiter-110 is the most cost-effective solution for launching a CEV to and fro from the ISS than surely it should be included in the proposal as a man-rated EELV in that category is not on the cards for anyone in the foreseeable future and even less likely to be adopted by NASA. It's also simpler too than the 120 which might appeal to the Ares I crowd ;-)

There are additional considerations, 2 of which are below:

1. We wanted to avoid the appearance that the Jupiter was a LEO launch vehicle. This is a MOON rocket and MARS rocket, and presenting the Jupiter-110 would detract from that. The danger is that if it were perceived as a LEO launch vehicle, it wouldn't be taken seriously for the lunar and Martian roles. We did not go into the lift capability of the other family members, but the Jupiter launch vehicle is capable of lifting in excess of 250mT to orbit if required, and we didn't want to risk loosing that perspective. It beats the pants off the Ares-V. But no one will notice that if they are all thinking "LEO launcher". The Mars guys should love this launch vehicle, because it gives them their interplanetary heavy lift launcher years ahead of the Ares-V, and still has plenty of room to grow if needed, while the Ares-V begins its life already maxed out at the limits of its capability. The Ares-V is very, very expensive, inefficient and uneconomical, while the Jupiter spreads its cost across the entire program, opening up all kinds of possibilities for interplanetary exploration.

2. The Jupiter-110 really only saves a single RS-68 engine and isn't that much simpler. The cost savings don't justify the loss of gaining flight experience with the Jupiter-120, because the 120 would become the LEO workhorse of choice, due to its lift capability.

Having said that, the 110 could be fielded if NASA wanted it. It would send 25-30mT to the ISS, more to a 28.5 degree orbit, directly competing with EELVs, something we chose not to do in this particular presentation.

Ok, the question: How many of you think the Jupiter-110 should be in the proposal - and more importantly, why?
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/18/2007 04:53 PM
Quote
marsavian - 18/5/2007  8:52 AM

Clongton,

Did you consider a Jupiter-110 with one centerline RS-68 purely for the ISS missions as the baseline Jupiter-120 looks overpowered for the job ?

It worked for ISS provided we flew about half full.  The margins were lower and obviously we have no engine out capacity like the 120 but all things considered even the Jupiter-110 is safer than the Ares I.  So if you want to save the expense of one RS-68 engine and don’t use the full capability of the ET then this is a good option.  Hey it’s not half full or half empty its just over designed :)

Both the Jupiter-110 and 120 are safer than the Ares I by a wide margin due to the higher performance margins in both designs.  Given this is Scott’s primary argument against the ELV’s we felt the best way to defeat this argument is turning it back around on them with an even safer design.

Right now Scott is in the position of advocating a less safe vehicle than the Jupiter-120.  Add all the near term and long term advantages of starting with the Jupiter-120 vs. the Ares I in the first place and Direct is clearly the best choice all things considered.

Let's see Ares1/5 is now offically less safe, not simple and definitely not soon.  Other than that the current plan is great :)




Title: Re: DIRECT v2.0
Post by: Pheogh on 05/18/2007 05:28 PM
SMetch, that brings up an interesting question. Have you guys thought about getting the astronauts themselves to start advocating DIRECT, based on safety margins alone. There must be an online forum of some type that the astronaut corp uses? Hopefully its not pre-mature to think so but after reading through the posts it would appear that it might be getting close to the time to start bringing together DIRECT's allies. Something similar to a "forward" of the proposal by more prominent individuals of the community.
Title: Re: DIRECT v2.0
Post by: on 05/18/2007 05:38 PM

Quote
clongton - 18/5/2007  6:58 AM  Please provide a list of what you see as key weaknesses.

Let me try to play "Dr. Stanley" (actually more like thinking like CBO):

1. We've never flown adjustable number of engines inside a launch vehicle before - really you have two vehicles with a lot of commonality, but because of this we have to have complete verification, validation, and qualification as man rated launch vehicles, we have to have to duplicate resources to support launching either of them(both large), and your budget's too small for that - thank you for playing, SLAM!
 

2. We need to deal with a contingency of longer ISS life due to pressure from international partners, but want to low ball the cost of US access for flights beyond ISS end-of-life, and you're one SRB too costly than Ares-I, thus we can't cover our contingency while advancing VSE.

3. We don't want to fly Orion on a EELV - period. Not even for test - we don't want to undercut our position that we need an Ares to boost ANY Orion for any reason.

Its hard to come up with things to object to - go and work the list on DIRECT 2.0 and its hard to find things. I can't even hypothesize another missing/hidden spec like the rs68 "gotcha" on V.1. All I can find are these "stretches", which aren't great. Like I said, DIRECT 2 is a good job. I hope it gets the "gold star" it, our space program, and our country deserve.

Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/18/2007 05:53 PM
Quote
nobodyofconsequence - 18/5/2007  10:38 AM
3. We don't want to fly Orion on a EELV - period. Not even for test - we don't want to undercut our position that we need an Ares to boost ANY Orion for any reason.

I was thinking the same thing as I was reading the proposal.  What is the point of the Delta IV/Orion launches?  Given that they appear to be trying to rule out EELVs, any flight that establishes an EELV/Orion capability would appear to be unacceptable.  (In other words, it is likely that people in Congress will say, "We already saw in 2009 that you can fly the Orion on a Delta IV.  Why don't we just use the Delta, cancel the Jupiter, and save ourselves a lot of money and time?")

Reading between the lines, I'm guessing that the purpose of the Delta IV/Orion launches is to accelerate the schedule?  What would it do to the schedule to stick with Jupiter launches exclusively?
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/18/2007 06:02 PM
Doesn't COTS already do that?
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 06:19 PM
Quote
nobodyofconsequence - 18/5/2007  1:38 PM

Quote
clongton - 18/5/2007  6:58 AM  Please provide a list of what you see as key weaknesses.

Let me try to play "Dr. Stanley" (actually more like thinking like CBO):



1. We've never flown adjustable number of engines inside a launch vehicle before - really you have is two vehicles with a lot of commonality, but because of this we have to have complete verification, validation, and qualification as man rated launch vehicles, we have to have to duplicate resources to support launching either of them(both large), and your budget's too small for that - thank you for playing, SLAM!
 

It’s far less expensive to qualify 2 launch vehicles that are part of the same family and nearly identical than it is to qualify 2 totally different launch vehicles, like the Ares-I and Ares-V, each of which requires its own resource pool, personnel and launch infrastructure. In addition, these “two” launch vehicles do not have “duplicate” resources, but operate from one single resource pool. The commonality between these two vehicles is so totally tight-knit, that in terms of support structure, personnel and launch infrastructure, they are the same vehicle. On the other hand, about the only thing the Ares-I and Ares-V will have in common is the name of the state they will launch from.

Quote
2. We need to deal with a contingency of longer ISS life due to pressure from international partners, but want to low ball the cost of US access for flights beyond ISS end-of-life, and you're one SRB too costly than Ares-I, thus we can't cover our contingency while advancing VSE.

The Jupiter-120 does cost a little more to fly, but only in terms of flight hardware, than the Ares-I. Per launch vehicle, that is not a lot. But then it’s designed to be capable of actually performing the mission of putting the Orion into orbit, something which the Ares-I was supposed to do, but cannot. The Jupiter is the only launch vehicle needed for the lunar mission, and once fielded, can wait as long as necessary as contingency planning proceeds with an extended-life ISS. In addition, flying on the Jupiter provides the experience for the ENTIRE lunar team, including manufacturers, astronauts and launch and processing personnel, that is going to be needed for the lunar missions. Flying on the Ares-I only covers ½ of the equation. The longer the ISS life is extended, the more distant and unlikely it becomes that the Ares-V will ever leave its power point presentations. Put Jupiter on the pad however, and the moon is put in the palm of your hand with the first operational launch.

Quote
3. We don't want to fly Orion on an EELV - period. Not even for test - we don't want to undercut our position that we need an Ares to boost ANY Orion for any reason.

The Delta will be used to qualify the man-rated RS-68 powerplant that even NASA needs for the Ares-V. That’s because the RS-68 IS the Delta powerplant. Regarding the Orion boilerplate, note that it is not a man-rated flight article. It is a boilerplate. It is designed to verify system integration, avionics, and things of that nature. The Delta used for these would not be a man-rated launch vehicle, something NASA has refused to pay for, and, so far, Boeing has chosen to not fund on its own nickel. Flight testing the Orion boilerplate on the same launch vehicle using the Jupiter flight engine makes the most economic and technical sense. Because it is available, it cannot be justified to wait an additional year to do the same testing on the Jupiter, unless it is NASA’s specific intent to delay fielding the Orion for as long as it can. I fail to see how that delay serves the national interests or the interests of the VSE.

Quote
Its hard to come up with things to object to - go and work the list on DIRECT 2.0 and its hard to find things. I can't even hypothesize another missing/hidden spec like the rs68 "gotcha" on V.1. All I can find are these "stretches", which aren't great. Like I said, DIRECT 2 is a good job. I hope it gets the "gold star" it, our space program, and our country deserve.


These thoughts are just off the top of my head and are "knee-jerk" reactions. If Stanley were to actually put forth such arguements, we are prepared to get very specific with technical answers, based on NASA's own data.

Thank you. Keep playing devils advocate. We appreciate it.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/18/2007 06:38 PM
Quote
clongton - 18/5/2007  11:47 AM

2. The Jupiter-110 really only saves a single RS-68 engine and isn't that much simpler. The cost savings don't justify the loss of gaining flight experience with the Jupiter-120, because the 120 would become the LEO workhorse of choice, due to its lift capability.


Why not go the other way then and just have a 3 RS-68 Jupiter-130 single launch vehicle every time ? To me it seems you either have the 3 variations or just the full large version if you are concerned about continuous flight experience and real commonality between the base and EDS version. In other words stick to your original idea of one vehicle in DIRECT Vers 1 but with another engine, consider it engine-out capability on the Moon missions ;-).
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/18/2007 06:52 PM
Quote
clongton - 18/5/2007  12:19 PM
Thank you. Keep playing devils advocate. We appreciate it.

CFE said this above, and I think it's worthy of a reply.

Quote
I'm concerned that the performance figures given in DIRECT V2 reflect a 30x120nmi orbit. DIRECT's critics are really going to latch onto this. I think it's best to give all performance figures in terms of a circular assembly orbit (such as the 120nmi orbit for Ares V.) My concerns temporarily turned me into a "Doubting Thomas," hence my attempts to verify the performance numbers.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/18/2007 07:06 PM
30x120nm is NASA's current baseline altitude, so any flak we get can equally be directed towards NASA.

The fact is that the poor altitude baseline is caused by Ares-I.   Even the smallest DIRECT launcher can easily support a far better 160nm altitude baseline instead, but this way we get an easy to understand apples-to-apples comparison with NASA's launchers.

But for now, what's good enough for NASA is good enough for us too.

Ross.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/18/2007 07:06 PM
Quote
clongton - 18/5/2007  11:19 AM

Quote
3. We don't want to fly Orion on an EELV - period. Not even for test - we don't want to undercut our position that we need an Ares to boost ANY Orion for any reason.
The Delta will be used to qualify the man-rated RS-68 powerplant that even NASA needs for the Ares-V. That’s because the RS-68 IS the Delta powerplant. Regarding the Orion boilerplate, note that it is not a man-rated flight article. It is a boilerplate. It is designed to verify system integration, avionics, and things of that nature. The Delta used for these would not be a man-rated launch vehicle, something NASA has refused to pay for, and, so far, Boeing has chosen to not fund on its own nickel. Flight testing the Orion boilerplate on the same launch vehicle using the Jupiter flight engine makes the most economic and technical sense. Because it is available, it cannot be justified to wait an additional year to do the same testing on the Jupiter, unless it is NASA’s specific intent to delay fielding the Orion for as long as it can. I fail to see how that delay serves the national interests or the interests of the VSE.

Is there any reason to fly Orion on the RS-68 test flights?  Can you fly them on a D-IV without an Orion?  Again, I foresee that the Delta/Orion combination is going to be a big issue with respect to political positioning, and it would be best to avoid having people react to this problem.
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 07:25 PM
Quote
Lee Jay - 18/5/2007  2:52 PM
Quote
clongton - 18/5/2007  12:19 PM
Thank you. Keep playing devils advocate. We appreciate it.

CFE said this above, and I think it's worthy of a reply.

Quote
I'm concerned that the performance figures given in DIRECT V2 reflect a 30x120nmi orbit. DIRECT's critics are really going to latch onto this. I think it's best to give all performance figures in terms of a circular assembly orbit (such as the 120nmi orbit for Ares V.) My concerns temporarily turned me into a "Doubting Thomas," hence my attempts to verify the performance numbers.
It is not the function of a launch vehicle to place a spacecraft into a circular orbit, but rather to place a spacecraft into an elliptical orbit with a high and low point. The spacecraft itself will circularize the orbit. The reasons for this are several, but the 3 main ones are:

1. An elliptical injection orbit increases the amount of mass for the IMLEO.
2. Circularizing the orbit is more efficiently accomplished by the spacecraft itself, once the launch vehicle places it into an elliptical injection orbit. It only has to power itself, and not all the dead weight of a nearly empty propellant tank.
3. It is much easier to dispose of the launch vehicle when it does not go into a circular orbit that might take years to decay, or would require the added complexity of ulage rockets to de-orbit the stage once the payload had been freed. The air resistance at the lower point serves to slow the stage to the point where it will drop into the ocean by itself. That assumes, of course, that the low point is actually within the boundary of the atmosphere. Otherwise this option doesn’t really buy us much and ulage motors would be needed to cause the orbit to decay sufficiently for stage disposal.

There are other reasons as well, but these are the chief ones.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/18/2007 07:28 PM
Quote
marsavian - 18/5/2007  2:38 PM

Why not go the other way then and just have a 3 RS-68 Jupiter-130 single launch vehicle every time ? To me it seems you either have the 3 variations or just the full large version if you are concerned about continuous flight experience and real commonality between the base and EDS version. In other words stick to your original idea of one vehicle in DIRECT Vers 1 but with another engine, consider it engine-out capability on the Moon missions ;-).

Also, the two RS-68 engines must already be throttled down towards the end of the ascent - as the propellant is burned away and the vehicle becomes lighter - in order to keep acceleration below 4g.   If you flew all three engines you would get much higher dynamic pressure around max-Q, and you would also have to shut one down and drag its dead weight along in the latter portion of the flight.   This dead weight directly reduces the mass of useful payload you can carry.   An RS-68 masses about 6.5 tons, so you reduce ultimate performance by that.

Additionally, you burn fuel a lot faster with three engines, and the ET isn't getting any larger.   I would have to run the numbers to confirm, but I believe the stage would run out of fuel before ever reaching orbital speeds.   That is why the 232 works so well.   The 3-engine core burns out before reaching orbit, and the EDS takes over for the last part of ascent.


The common core stage itself though, is exactly the same for either configuration.

Getting back to the source of this discussion point though, flying a single engined version - it is indeed doable - but adding a third configuration adds a third flight certification program also, and DIRECT's key goal has always been to avoid unnecessary development costs wherever possible.

The J-120 can do ISS missions, Hubble missions and Lunar missions with only one qualification program. It can even do early qualification test flights for the 232 configuration even before the EDS is ready.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/18/2007 07:39 PM
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nobodyofconsequence - 18/5/2007  1:38 PM

Quote
clongton - 18/5/2007  6:58 AM  Please provide a list of what you see as key weaknesses.

Let me try to play "Dr. Stanley" (actually more like thinking like CBO):

1. We've never flown adjustable number of engines inside a launch vehicle before - really you have two vehicles with a lot of commonality, but because of this we have to have complete verification, validation, and qualification as man rated launch vehicles, we have to have to duplicate resources to support launching either of them(both large), and your budget's too small for that - thank you for playing, SLAM!

What we propose is far less costly than fielding Ares-I and Ares-V together.   They not only require two qualification programs, but also two DDT&E programs and two operations programs to be funded.   DIRECT deletes one of each of those.

Quote
2. We need to deal with a contingency of longer ISS life due to pressure from international partners, but want to low ball the cost of US access for flights beyond ISS end-of-life, and you're one SRB too costly than Ares-I, thus we can't cover our contingency while advancing VSE.

For the $20 billion required between 2011 and 2017 to pay to develop Ares-V in addition to Ares-I, we could afford to fly more than 100 additional flights of the Jupiter 120.

100 Jupiter-120 flights can launch 4,800 tons to orbit (13 times the total mass of the fully completed ISS) for the total expenditure NASA plans to invests just to get the first Ares-V flying.


Quote
3. We don't want to fly Orion on a EELV - period. Not even for test - we don't want to undercut our position that we need an Ares to boost ANY Orion for any reason.

Orion can be tested on any vehicle.   However the man-rated RS-68 engine ought to be flight tested before flying people.   Delta-IV offers an ideal existing test-bed for such work.   It seems a waste not to utilize such a test flight without testing other valuable Constellation-related hardware at the same time.

While your mileage may vary, we see an Orion Launch Abort Test and parachute deployment/recovery test as being a useful secondary mission if required.   If this is politically unacceptable, then it can still be performed on another, more politically palatable, vehicle.


Quote
Its hard to come up with things to object to - go and work the list on DIRECT 2.0 and its hard to find things. I can't even hypothesize another missing/hidden spec like the rs68 "gotcha" on V.1. All I can find are these "stretches", which aren't great. Like I said, DIRECT 2 is a good job. I hope it gets the "gold star" it, our space program, and our country deserve.

You are not the first person to identify that there are very few things which detractors can grab a hold of on the new DIRECT plan.   It certainly appears to have a lot fewer hurdles than the existing Ares-I / V plan.

Ross.
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 07:54 PM
Quote
SolarPowered - 18/5/2007  3:06 PM

Quote
clongton - 18/5/2007  11:19 AM

Quote
3. We don't want to fly Orion on an EELV - period. Not even for test - we don't want to undercut our position that we need an Ares to boost ANY Orion for any reason.
The Delta will be used to qualify the man-rated RS-68 powerplant that even NASA needs for the Ares-V. That’s because the RS-68 IS the Delta powerplant. Regarding the Orion boilerplate, note that it is not a man-rated flight article. It is a boilerplate. It is designed to verify system integration, avionics, and things of that nature. The Delta used for these would not be a man-rated launch vehicle, something NASA has refused to pay for, and, so far, Boeing has chosen to not fund on its own nickel. Flight testing the Orion boilerplate on the same launch vehicle using the Jupiter flight engine makes the most economic and technical sense. Because it is available, it cannot be justified to wait an additional year to do the same testing on the Jupiter, unless it is NASA’s specific intent to delay fielding the Orion for as long as it can. I fail to see how that delay serves the national interests or the interests of the VSE.

Is there any reason to fly Orion on the RS-68 test flights?  Can you fly them on a D-IV without an Orion?  Again, I foresee that the Delta/Orion combination is going to be a big issue with respect to political positioning, and it would be best to avoid having people react to this problem.
1.   The RS-68 is the engine powering the Delta today. It absolutely IS the vehicle to test the man-rated version on. NASA won’t even argue that.
2.   Systems integrations testing between the Orion and a launch vehicle using the powerplant that will be sending it into space is the right thing to do. The Delta, with the man-rated RS-68, will be ready to do that about 1 to 1½ years before the Jupiter is ready to fly the Orion. Truth be told, the Orion that would be on the Delta would not be a flight-certified vehicle, only a boilerplate. The Delta doing the testing would not be capable of putting a fully outfitted Orion into orbit, so there is no “danger” on that score of undermining the Jupiter. There is no good reason not to do it, other than to deliberately delay fielding the spacecraft. The boilerplate can provide a lot of data that will be incorporated into the flight article on a Jupiter. No fully configured and fueled Orion spacecraft can be placed into orbit on the Deltas being used today. The full-up Orion spacecraft is too heavy. But preliminary testing can be done. There is simply no good reason not to do that. No one is going to be able to tell Congress “see, the Delta CAN launch Orion” because it can’t, not in the foreseeable future. Someday – yes, but not anytime soon.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/18/2007 08:23 PM
Chuck, thanks for the explanation about Delta/Orion.  You've convinced me that it's not really going to be a serious political problem, and I now see the technical need for those flights.

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clongton - 18/5/2007  9:47 AM
... the Jupiter launch vehicle is capable of lifting in excess of 250mT to orbit if required...

I was wondering what the configuration is that can lift 250 mT?  That sounds quite impressive!
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 08:25 PM
Quote
SolarPowered - 18/5/2007  4:23 PM

Chuck, thanks for the explanation about Delta/Orion.  You've convinced me that it's not really going to be a serious political problem, and I now see the technical need for those flights.

Quote
clongton - 18/5/2007  9:47 AM
... the Jupiter launch vehicle is capable of lifting in excess of 250mT to orbit if required...

I was wondering what the configuration is that can lift 250 mT?  That sounds quite impressive!
It's a Jupiter-3xx. It may or may not ever be needed. But the fact that it CAN be flown, and is a direct derivative of the Jupiter family, is what is impressive. Having a lift requirement for 250mT is a problem I would LOVE to have. However, it is unlikely to be needed for a very, very long time. But it is on the table and available.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/18/2007 08:40 PM
Just for the record, I thought I would post the table from the unreleased internal version of the ESAS Report which assesses the RS-68 compared to the SSME.

It is useful for judging how reliable it is expected to be against an already well-proven man-rated engine, and indicates that needed changes are all fairly straight forward for man-rating the engine.

This table DOES NOT apply to the higher performance 106% power level RS-68 variant NASA has planned for the Ares-V - just for the RS-68 at standard performance levels.   Considerably more changes are required when operating the engine at the higher specification on a manned flight.



Ross.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/18/2007 08:41 PM
Chuck, it is quite amazing that you'all have been able to come up with such a versatile system of rockets from the existing STS pieces, while the ARES system is quite the opposite.  I am quite impressed with your work.

Will there be a table available that shows the other useful configurations, like the 3xx versions?
Title: Re: DIRECT v2.0
Post by: kraisee on 05/18/2007 08:42 PM
Quote
SolarPowered - 18/5/2007  4:41 PM

Will there be a table available that shows these configurations?

Yes, we are planning an Appendix to be added in the future which will show many of the growth options.

It is not however a major effort right now, because our focus is currently on matching and beating Ares performance & costs primarily for the Lunar program and also the remaining ISS program.

The growth options are unnecessary for those requirements as the J-120 offers double Ares-I's performance and a pair of J-232's already offers 42% more performance than the Ares-I/V combo - and do so all for roughly half the development costs.

Ross.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/18/2007 08:59 PM
If  Space-x comes through and builds a reliable ISS Rocket,  then all those BILLIONS spent on ARES I become a total waste.   Which is not the case with Direct.   I am at a loss to think of any advantage ARES I has except for momentum.   You guys seem to have a royal flush.  But NASA can set the rules for the card game.
Title: Re: DIRECT v2.0
Post by: Jim on 05/18/2007 09:08 PM
Quote
veedriver22 - 18/5/2007  4:59 PM

If  Space-x comes through and builds a reliable ISS Rocket,  then all those BILLIONS spent on ARES I become a total waste.   Which is not the case with Direct.   I am at a loss to think of any advantage ARES I has except for momentum.   You guys seem to have a royal flush.  But NASA can set the rules for the card game.


Big if.

COTS vehicles do not replace Orion flights to the ISS, they only supplement them (and maybe fill the gap).  There still needs be a way to launch the CEV into LEO
Title: Re: DIRECT v2.0
Post by: clongton on 05/18/2007 09:12 PM
Quote
veedriver22 - 18/5/2007  4:59 PM

If  Space-x comes through and builds a reliable ISS Rocket,  then all those BILLIONS spent on ARES I become a total waste.   Which is not the case with Direct.   I am at a loss to think of any advantage ARES I has except for momentum.   You guys seem to have a royal flush.  But NASA can set the rules for the card game.
As much as I dislike the Ares-I, don't be so quick to dismiss it. If NASA can get it to work correctly, then it fits their philosophy of the 1.5 launch architecture; a small crew launcher (the 1/2 part) and a large cargo launcher. The trouble is that the entire architecture is inflexable, has no growth options, and is enormously expensive and wasteful to impliment, operate and maintain. But it can work. Even if SpaceX does as you say, the Ares-I can still send the Orion to meet the departing LSAM for the moon. That's the design intent, and it can work that way, just not efficiently. But if the Ares-V never gets built, then you are correct - all those billions for the Ares-I will have been wasted, because it can't do anything else.

Direct, on the other hand, has all the bases covered and can serve this nation in an enormously versitile manner for decades to come. It also has the ability, unlike the Ares architecture, to weather congressional budget difficulties, and still be capable of fulfilling the VSE. But for the Ares, as you saw recently, even a "little" hit can cause enormous difficulties. NASA didn't even have a cut in funding. All that happened to them was that they didn't get their raise, and look what happened. For Direct, that would have been a hiccup.
Title: Re: DIRECT v2.0
Post by: imfan on 05/18/2007 10:05 PM
Quote
Jim - 18/5/2007  11:08 PM

Quote
veedriver22 - 18/5/2007  4:59 PM

If  Space-x comes through and builds a reliable ISS Rocket,  then all those BILLIONS spent on ARES I become a total waste.   Which is not the case with Direct.   I am at a loss to think of any advantage ARES I has except for momentum.   You guys seem to have a royal flush.  But NASA can set the rules for the card game.


Big if.

COTS vehicles do not replace Orion flights to the ISS, they only supplement them (and maybe fill the gap).  There still needs be a way to launch the CEV into LEO

CEV to ISS could be launched on manrated EELV. There might be problem with lift capacity, but may be solved a) by offloading pretty lot of fuel from CEV b)letting the CEV to do inject burn. what do we want to do with all that fuel in LEO?
There is a question if it is cost wise to have another launcher for CEV, but if not, you can lauch it on direct anyway
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/18/2007 10:20 PM
Quote
kraisee - 18/5/2007  1:28 PM
Also, the two RS-68 engines must already be throttled down towards the end of the ascent - as the propellant is burned away and the vehicle becomes lighter - in order to keep acceleration below 4g.   If you flew all three engines you would get much higher dynamic pressure around max-Q, and you would also have to shut one down and drag its dead weight along in the latter portion of the flight.   This dead weight directly reduces the mass of useful payload you can carry.   An RS-68 masses about 6.5 tons, so you reduce ultimate performance by that.

Additionally, you burn fuel a lot faster with three engines, and the ET isn't getting any larger.   I would have to run the numbers to confirm, but I believe the stage would run out of fuel before ever reaching orbital speeds.   That is why the 232 works so well.   The 3-engine core burns out before reaching orbit, and the EDS takes over for the last part of ascent.
Ross.

It would be possible to do a 130 with a blank (a really heavy one) for an upper stage as a test, correct?  I'm not saying that's necessary, but the whole thing would just go ballistic and then land in the Atlantic, correct?

Lee Jay
Title: Re: DIRECT v2.0
Post by: kraisee on 05/18/2007 11:36 PM
Quote
Lee Jay - 18/5/2007  6:20 PM

It would be possible to do a 130 with a blank (a really heavy one) for an upper stage as a test, correct?  I'm not saying that's necessary, but the whole thing would just go ballistic and then land in the Atlantic, correct?

Lee Jay

Yes, absolutely.   We will need a test flight of the 3-engined configuration before the EDS is ready, and that would technically be a "Jupiter 130".

Two tests for an EDS with no engines and only a small amount of propellant on board (to test boiloff) are planned in our manifest already: May 2013 and May 2014 (see the manifest below).

These could be flown with three-engined cores instead of the two, although the engines would have to be flown throttled down and one would have to be switched off during the ascent to ensure acceleration g forces don't climb too high, but it is something to be examined.

Ross.

Title: Re: DIRECT v2.0
Post by: Smatcha on 05/19/2007 12:00 AM
Quote
kraisee - 18/5/2007  4:36 PM

Quote
Lee Jay - 18/5/2007  6:20 PM

It would be possible to do a 130 with a blank (a really heavy one) for an upper stage as a test, correct?  I'm not saying that's necessary, but the whole thing would just go ballistic and then land in the Atlantic, correct?

Lee Jay

Yes, absolutely.   We will need a test flight of the 3-engined configuration before the EDS is ready, and that would technically be a "Jupiter 130".

Two tests for an EDS with no engines and only a small amount of propellant on board (to test boiloff) are planned in our manifest already: May 2013 and May 2014 (see the manifest below).

These could be flown with three-engined cores instead of the two, although the engines would have to be flown throttled down and one would have to be switched off during the ascent to ensure acceleration g forces don't climb too high, but it is something to be examined.

Ross.



Having a planned engine shut down test would be great way to prove what the range of payload levels/ascent options where we could lose an engine and still save the mission.  Particularly important for the second launch.

In one scenario with the more expensive spacecraft elements (CEV+LSAM) going up on the second launch to rendezvous with the comparatively less expensive EDS this could be important capability to have.  Given the throttle back typical of most optimized ascents we would just run the two remaining engines at full to compensate for the lost engine.  Just make everything also works with a nominal 60% throttle back of three and we should be good to go.  In addition the second launches upper stage (below the LSAM) could be used to do the LOA and even PDI helping to keep the LSAM mass down.

Just some ideas.  It’s nice to have good mass levels on both 2xJupiter-xxx launches to work with.  The one size fits all ESAS is very limiting in terms of options now and in the future.


Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/19/2007 12:17 AM
Quote
kraisee - 18/5/2007  5:36 PM

Quote
Lee Jay - 18/5/2007  6:20 PM

It would be possible to do a 130 with a blank (a really heavy one) for an upper stage as a test, correct?  I'm not saying that's necessary, but the whole thing would just go ballistic and then land in the Atlantic, correct?

Lee Jay

Yes, absolutely.   We will need a test flight of the 3-engined configuration before the EDS is ready, and that would technically be a "Jupiter 130".

Two tests for an EDS with no engines and only a small amount of propellant on board (to test boiloff) are planned in our manifest already: May 2013 and May 2014 (see the manifest below).

A 230?

Quote
These could be flown with three-engined cores instead of the two, although the engines would have to be flown throttled down and one would have to be switched off during the ascent to ensure acceleration g forces don't climb too high, but it is something to be examined.

I guess the two engined one is a 220.

Why do you have to worry about g-forces during a test of this type?  Is there equipment on board that's sensitive to g's?

Lee Jay
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/19/2007 11:16 AM
What is the largest payload (length and diameter) that Direct can launch without needing launch infrastructure changes?
Title: RE: DIRECT v2.0
Post by: Jim on 05/19/2007 12:45 PM
Quote
PMN1 - 19/5/2007  7:16 AM

What is the largest payload (length and diameter) that Direct can launch without needing launch infrastructure changes?

Trick question.  The infrastructure for processing and encapsulating Direct/Ares V type spacecraft has yet to be built.  Some might say the VAB hook height but if that were a constraint, then the payload could be installed at the pad by yet to be built infrastructure.

Controllability is the real design driver
Title: Re: DIRECT v2.0
Post by: Justin Space on 05/19/2007 04:05 PM
Quote
Pheogh - 18/5/2007  12:28 PM

SMetch, that brings up an interesting question. Have you guys thought about getting the astronauts themselves to start advocating DIRECT, based on safety margins alone. There must be an online forum of some type that the astronaut corp uses? Hopefully its not pre-mature to think so but after reading through the posts it would appear that it might be getting close to the time to start bringing together DIRECT's allies. Something similar to a "forward" of the proposal by more prominent individuals of the community.

No, no and no.
Title: Re: DIRECT v2.0
Post by: Jim on 05/19/2007 04:32 PM
Quote
Justin Space - 19/5/2007  12:05 PM

Quote
Pheogh - 18/5/2007  12:28 PM

SMetch, that brings up an interesting question. Have you guys thought about getting the astronauts themselves to start advocating DIRECT, based on safety margins alone. There must be an online forum of some type that the astronaut corp uses? Hopefully its not pre-mature to think so but after reading through the posts it would appear that it might be getting close to the time to start bringing together DIRECT's allies. Something similar to a "forward" of the proposal by more prominent individuals of the community.

No, no and no.

The stick is suppose to be a design of the astronaut office
Title: Re: DIRECT v2.0
Post by: RedSky on 05/19/2007 06:02 PM
Quote
Jim - 19/5/2007  11:32 AM
The stick is suppose to be a design of the astronaut office

That was the "original" 4-seg SRB SSME US stick.  Maybe their feelings have changed for the all new Stick 2.
Besides, how many of the current astronauts are expected to be around in 2015... waiting so many years after STS before flying again.  If they are so concerned about safety (Stick vs Direct), then why would they even think of riding STS to orbit now?
Title: RE: DIRECT v2.0
Post by: William Barton on 05/19/2007 06:20 PM
Quote
Jim - 19/5/2007  8:45 AM

Quote
PMN1 - 19/5/2007  7:16 AM

What is the largest payload (length and diameter) that Direct can launch without needing launch infrastructure changes?

Trick question.  The infrastructure for processing and encapsulating Direct/Ares V type spacecraft has yet to be built.  Some might say the VAB hook height but if that were a constraint, then the payload could be installed at the pad by yet to be built infrastructure.

Controllability is the real design driver

My recollection is, during the Apollo era, there was some discussion of variants (particularly the nuclear upper stage variants) that were too tall for VAB. There was some talk of putting a crane on top of the VAB to handle final assembly. I don't recall what was said about the launch tower, etc.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/19/2007 06:27 PM
Quote
PMN1 - 19/5/2007  7:16 AM

What is the largest payload (length and diameter) that Direct can launch without needing launch infrastructure changes?

Unless you continue to fly Shuttle, we're going to have to have some infrastructure changes.   The question becomes, how big those changes are to be.   NASA is currently planning an all-out replacement of virtually everything to support Ares-I and Ares-V.   We are not.

The Jupiter 120 and 232 launch vehicles which we have proposed require only reasonable and minimal changes to the existing Shuttle infrastructure.   We share commonality through retaining the 4-segment SRB's and an 8.4m diameter core tank structure, which means that *most* elements used to process those today can be reused again by Jupiter.   Changes are pretty-much limited to supporting the new engine location under the core, and the addition of 8.4m diameter payloads and upper stages above the tank.

Both Jupiter vehicles are already planned to fly with large payload shrouds allowing payloads of up to 24.5ft (7.46m) diameter.   The length of an allowable payload is determined by the length of the fairing.   We are planning two shrouds, a "short" allowing 48ft (14.5m) long payloads, and a "long" which can launch 75ft (23m) payloads.

The option exists to make a payload fairing even wider than the standard 8.4m diameter core too.   10m or 12m diameter payload fairings are possible, allowing even larger modules to be lifted. Those would require different work platforms to be installed in the upper levels of the VAB though - not an impossible proposition, just more expensive.

For now, we plan to stay at 8.4m diameter for all payload shrouds and upper stages.   This will allow any module to be processed in any of the VAB's highbays which support Jupiter vehicles.   They would be largely interchangeable.

Ross.
Title: Re: DIRECT v2.0
Post by: Jim on 05/19/2007 06:37 PM
Payload processing facilities have to be built for any new heavy lift vehicle
Title: Re: DIRECT v2.0
Post by: kraisee on 05/19/2007 06:45 PM
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Jim - 19/5/2007  2:37 PM

Payload processing facilities have to be built for any new heavy lift vehicle

Absolutely, one is needed for processing Orion's.   One is needed for processing LSAM's.   A place has to be found to process the EDS (possibly somewhere inside VAB).   And if other (currently unplanned) large payloads are required, space will have to be found for those also.

Ross.
Title: Re: DIRECT v2.0
Post by: Jim on 05/19/2007 06:56 PM
CEV is using the SSPF for nonhazardous processing.  Hazardous processing will be done in the MPPF.

The LSAM might also use the SSPF for nonhazardous processing (depends on the final configuration and size).  A new facility will have to be built for encapsulation and fueling.

The EDS will be factory to pad just like the Ares I Upperstage.  No facility needed
Title: Re: DIRECT v2.0
Post by: MKremer on 05/19/2007 07:21 PM
How and where was the LM fueled, balanced, and encapsulated? Would the future LSAM be too large for the same locations and procedures?
Title: Re: DIRECT v2.0
Post by: Jim on 05/19/2007 07:39 PM
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MKremer - 19/5/2007  3:21 PM

How and where was the LM fueled, balanced, and encapsulated? Would the future LSAM be too large for the same locations and procedures?

It was encapsulated in the O&C (where the CEV will be built) with the CSM on top.  They were all fueled at the pad using the MSS.
Title: Re: DIRECT v2.0
Post by: MKremer on 05/19/2007 08:19 PM
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Jim - 19/5/2007  2:39 PM
It was encapsulated in the O&C (where the CEV will be built) with the CSM on top.  They were all fueled at the pad using the MSS.
Thanks.

Is pre-fueling (non-cryo) for the SM better in terms of time prior to final stacking/rollout, or does the extra safety precautions make that less efficient?

If it's deemed to be better to pre-fuel, then what was the reasoning behind making Apollo missions wait until at the pad to do that?
(Or, is it a case of "hindsight is 20/20" and it's proven to be better/more efficient/safer to fuel all non-cryo tanks prior to rollout to the pad?)


Title: Re: DIRECT v2.0
Post by: Jim on 05/19/2007 08:28 PM
It reduces the infrastructure needed at the pad and reduces time on pad
Title: Re: DIRECT v2.0
Post by: Scotty on 05/19/2007 11:30 PM
The plan at this time is to have the entire Orion-Ares cycle to take 8 or less weeks.
That is: stack, check out, move to the pad, launch and get the ML moved back to the VAB ready to start the cycle again in under 8 weeks.
They want to be able to fly 5 times each year off the single new ML, with the option for 6 flights per year.
You do the math!
Title: Re: DIRECT v2.0
Post by: nacnud on 05/20/2007 12:22 AM
Sounds similar in timescale to an Ariane V launch campaign.
Title: Re: DIRECT v2.0
Post by: Crispy on 05/20/2007 10:34 AM
I reckon the Orion/EELV launches could be a hook to hang criticisms on. "we said no already, so we'll still say no" sort of thing.
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/20/2007 02:43 PM
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Jim - 19/5/2007  9:32 AM

Quote
Justin Space - 19/5/2007  12:05 PM

Quote
Pheogh - 18/5/2007  12:28 PM

SMetch, that brings up an interesting question. Have you guys thought about getting the astronauts themselves to start advocating DIRECT, based on safety margins alone. There must be an online forum of some type that the astronaut corp uses? Hopefully its not pre-mature to think so but after reading through the posts it would appear that it might be getting close to the time to start bringing together DIRECT's allies. Something similar to a "forward" of the proposal by more prominent individuals of the community.

No, no and no.

The stick is suppose to be a design of the astronaut office

Jim, do you think this would be a good path to pursue?  The Juipter-120 has a lot of margin with proven equipment in direct contrast to the Ares I.

The fact that it also supports more of the current STS base while providing a foundation to build on towards the Moon is another nice feature.  Also we have had some interest from the unmanned exploration side of NASA (JPL,GSC) in terms of exciting missions now possible with a vehicle capable of placing a  +48mT +8m diameter mission in orbit.  Mars sample return and other Earth resolving telescopes for example.

Title: Re: DIRECT v2.0
Post by: marsavian on 05/20/2007 03:03 PM
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SMetch - 20/5/2007  9:43 AM

Quote
Jim - 19/5/2007  9:32 AM

Quote
Justin Space - 19/5/2007  12:05 PM

Quote
Pheogh - 18/5/2007  12:28 PM

SMetch, that brings up an interesting question. Have you guys thought about getting the astronauts themselves to start advocating DIRECT, based on safety margins alone. There must be an online forum of some type that the astronaut corp uses? Hopefully its not pre-mature to think so but after reading through the posts it would appear that it might be getting close to the time to start bringing together DIRECT's allies. Something similar to a "forward" of the proposal by more prominent individuals of the community.

No, no and no.

The stick is suppose to be a design of the astronaut office

Jim, do you think this would be a good path to pursue?  The Juipter-120 has a lot of margin with proven equipment in direct contrast to the Ares I.

The fact that it also supports more of the current STS base while providing a foundation to build on towards the Moon is another nice feature.  Also we have had some interest from the unmanned exploration side of NASA (JPL,GSC) in terms of exciting missions now possible with a vehicle capable of placing a  +48mT +8m diameter mission in orbit.  Mars sample return and other Earth resolving telescopes for example.


You have to convince both them and NASA that the crew would survive one SRB of DIRECT not lighting up at launch or one/both blowing up in flight. Once you do that, your design will be accepted. It really is that simple given the presumption that safety is the overriding issue here and main reason for Ares I.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/20/2007 03:14 PM
Isn't that the whole point of the crew escape system?
Title: Re: DIRECT v2.0
Post by: RedSky on 05/20/2007 03:33 PM
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marsavian - 20/5/2007  10:03 AM
You have to convince both them and NASA that the crew would survive one SRB of DIRECT not lighting up at launch or one/both blowing up in flight. Once you do that, your design will be accepted. It really is that simple given the presumption that safety is the overriding issue here and main reason for Ares I.

If that is such a concern for the astronauts, why are they willing to still ride the STS today (and without a Launch Abort System)?  Direct has many components with a history of flight experience and probably better understood flight and control characteristics compared to Ares I, which is much more of a completely new vehicle.  Saying it may be safer in one parameter does not mean other issues (flying characteristics, separation from a still thrusting SRB, etc) won't make it worse.
Title: Re: DIRECT v2.0
Post by: Thomas ESA on 05/20/2007 03:41 PM
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clongton - 18/5/2007  6:58 AM

Quote
Thomas ESA - 18/5/2007  4:55 AM

Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.
Tom (and everyone):
Please provide a list of what you see as key weaknesses.

No. I want you to list as your key weaknesses. I am very disapointed with your reply, as it seems you don't know.

Title: Re: DIRECT v2.0
Post by: marsavian on 05/20/2007 03:56 PM
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RedSky - 20/5/2007  10:33 AM

Quote
marsavian - 20/5/2007  10:03 AM
You have to convince both them and NASA that the crew would survive one SRB of DIRECT not lighting up at launch or one/both blowing up in flight. Once you do that, your design will be accepted. It really is that simple given the presumption that safety is the overriding issue here and main reason for Ares I.

If that is such a concern for the astronauts, why are they willing to still ride the STS today (and without a Launch Abort System)?  Direct has many components with a history of flight experience and probably better understood flight and control characteristics compared to Ares I, which is much more of a completely new vehicle.  Saying it may be safer in one parameter does not mean other issues (flying characteristics, separation from a still thrusting SRB, etc) won't make it worse.

Because they have no choice if they want to do the job they love. This is *the* critical weakness of DIRECT compared to Ares I. Assure everybody that the crew can more likely than not survive these scenarios and you have it sold.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/20/2007 03:58 PM
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Lee Jay - 20/5/2007  10:14 AM

Isn't that the whole point of the crew escape system?


Not really if it can't be deployed in time.
Title: Re: DIRECT v2.0
Post by: MySDCUserID on 05/20/2007 05:40 PM
It would be nice to have a simple table that provides a quick comparison of DIRECT with Ares.
Title: Re: DIRECT v2.0
Post by: Verio Fryar on 05/20/2007 06:01 PM

Quote
nacnud - 19/5/2007  2:22 AM

Sounds similar in timescale to an Ariane V launch campaign.

I think the Ariane V launch campaign is only 3 weeks:

http://www.arianespace.com/site/launcher/launcher_campaign.html

 

Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/20/2007 06:11 PM
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Thomas ESA - 20/5/2007  4:41 PM

Quote
clongton - 18/5/2007  6:58 AM

Quote
Thomas ESA - 18/5/2007  4:55 AM

Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.
Tom (and everyone):
Please provide a list of what you see as key weaknesses.

No. I want you to list as your key weaknesses. I am very disapointed with your reply, as it seems you don't know.


I think you are being a little harsh. The DIRECT editors will have addressed the weaknesses that they found, and it really is best for a third party to identify remaining weaknesses that might have escaped attention.
Title: Re: DIRECT v2.0
Post by: Jim on 05/20/2007 06:36 PM
Quote
SMetch - 20/5/2007  10:43 AM

Jim, do you think this would be a good path to pursue?  The Juipter-120 has a lot of margin with proven equipment in direct contrast to the Ares I.

The fact that it also supports more of the current STS base while providing a foundation to build on towards the Moon is another nice feature.  Also we have had some interest from the unmanned exploration side of NASA (JPL,GSC) in terms of exciting missions now possible with a vehicle capable of placing a  +48mT +8m diameter mission in orbit.  Mars sample return and other Earth resolving telescopes for example.


Almost too big.  Those spacecraft will cost bilions
Title: Re: DIRECT v2.0
Post by: rumble on 05/20/2007 07:06 PM
Quote
marsavian - 20/5/2007  10:03 AM

You have to convince both them and NASA that the crew would survive one SRB of DIRECT not lighting up at launch or one/both blowing up in flight. Once you do that, your design will be accepted. It really is that simple given the presumption that safety is the overriding issue here and main reason for Ares I.

The "SRB blowing up in flight" scenario is one both Ares-I and Jupiter 1&2 would have to deal with.  

The slight 1-million-pounds-of-lift imbalance of only one SRB lighting in a shuttle-esque stack would have much larger concerns than just the crew.  Can you imagine a cart-wheeling launch vehicle with a core stage quickly disintegrating and a recently liberated and now tumbling SRB (with a thrust/weight ratio of 1.75:1!!) bouncing around KSC...and then what happens when range safety blows it up?  If the LAS does make it away, the crew may be the only people near the pad that are safe.

I understand the concern, but what are the real chances that an SRB won't light?  Not zero, I realize, but it's gotta be darn low.
Title: Re: DIRECT v2.0
Post by: Marsman on 05/20/2007 07:13 PM
The SRB's will light. There is something like quadruple redundancy in each system. The igniters have worked to perfection each time.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/20/2007 07:50 PM
If I understand correctly, Range Safety has the ability to command an SRB to jettison its nozzle and nose cone.  If that is done, the SRB produces near zero thrust.  Even it that's not done, the thrust:weight ratio at liftoff with all engines burning is around 1.3:1; with a single solid going and the liquid engines shut down, I don't think there's enough thrust to pull the stack away from the hold-down clamps.

So, I don't think that a failure to light would necessarily be a disaster.  (Not to mention the fact that it's probably more likely that a random 747 will crash into the fueled stack than an SRB will fail to light.)
Title: Re: DIRECT v2.0
Post by: Avron on 05/20/2007 08:04 PM
Quote
SolarPowered - 20/5/2007  3:50 PM

If I understand correctly, Range Safety has the ability to command an SRB to jettison its nozzle and nose cone.  If that is done, the SRB produces near zero thrust.  Even it that's not done, the thrust:weight ratio at liftoff with all engines burning is around 1.3:1; with a single solid going and the liquid engines shut down, I don't think there's enough thrust to pull the stack away from the hold-down clamps.

So, I don't think that a failure to light would necessarily be a disaster.  (Not to mention the fact that it's probably more likely that a random 747 will crash into the fueled stack than an SRB will fail to light.)

Agreed..the only issue with all engines "shutdown", the hold down bolts would have fired at the time the inital signal was given to ignite the SRB's, so eh.. Timber?
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/20/2007 08:08 PM
I just noticed something quite interesting:

Major expendables consumed per STS mission: 1 ET

Major expendables consumed per Jupiter 120 mission:  1 ET + 2 RS-68 engines.

Plus, with the STS you have a huge and complex shuttle orbiter that has to be refurbished after each mission, which is replaced with the much smaller and simpler Orion on Jupiter, and only on manned missions.

At this point, I'm really scratching my head about the "reusable" part of the STS concept...
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/20/2007 08:11 PM
Quote
Avron - 20/5/2007  1:04 PM
Agreed..the only issue with all engines "shutdown", the hold down bolts would have fired at the time the inital signal was given to ignite the SRB's, so eh.. Timber?

Yah, I suppose that might be a problem...

I do wonder, though, whether it would be "Timber", or would it just sit there?  I'm sure somebody ran those numbers 30 years ago.

(Edit: Do they really release the holddowns at the same time they light the solids?  My recollection is that they release the clamps shortly thereafter, to give the thrust time to stabilize.  But this is just the hazy recollection of somebody who's not involved with the program.)
Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/20/2007 08:44 PM
AFAIK the Shuttle stack is held down by long pins which are pulled through holes by the thrust force. It isn't a hold-and-release system like SpaceX use.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/20/2007 08:58 PM
The STS is held down by four 3.5" diameter bolts on each SRB aft skirt.  There is a frangeable nut on top of each that is broken and captured at the same time the SRBs are ignited.
Title: Re: DIRECT v2.0
Post by: Jim on 05/20/2007 09:55 PM
Quote
Kaputnik - 20/5/2007  4:44 PM

AFAIK the Shuttle stack is held down by long pins which are pulled through holes by the thrust force. It isn't a hold-and-release system like SpaceX use.

Lee jay is right.  No pins
Title: Re: DIRECT v2.0
Post by: Jim on 05/20/2007 09:59 PM
Quote
SolarPowered - 20/5/2007  3:50 PM

If I understand correctly, Range Safety has the ability to command an SRB to jettison its nozzle and nose cone.  If that is done, the SRB produces near zero thrust.  Even it that's not done, the thrust:weight ratio at liftoff with all engines burning is around 1.3:1; with a single solid going and the liquid engines shut down, I don't think there's enough thrust to pull the stack away from the hold-down clamps.

So, I don't think that a failure to light would necessarily be a disaster.  (Not to mention the fact that it's probably more likely that a random 747 will crash into the fueled stack than an SRB will fail to light.)

Incorrect.

Range safety destruct charges run the length of the booster and would split the case.

If the SRB's light and the bolts don't go, the stack will still go.
Title: Re: DIRECT v2.0
Post by: shostetler on 05/20/2007 10:49 PM
I'm curious about this whole Direct 2.0 and Ares/Orion. What happens if one of the Orion or Ares rockets meets a disaster similar to one of the shuttles? What are we going to do then? Will NASA come out and just give up? I don't think so. It seems everybody wants a fail safe method of getting into space. Granted the shuttle may have over extended it's use as it is aging significantly, but why doesn't NASA keep with the program as it knows works already and build on that? It's almost as though they just love to spend money.
Title: Re: DIRECT v2.0
Post by: clongton on 05/20/2007 11:02 PM
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Thomas ESA - 20/5/2007  11:41 AM

Quote
clongton - 18/5/2007  6:58 AM

Quote
Thomas ESA - 18/5/2007  4:55 AM

Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.
Tom (and everyone):
Please provide a list of what you see as key weaknesses.

No. I want you to list as your key weaknesses. I am very disapointed with your reply, as it seems you don't know.
We know what we think our weaknesses are and are working to mitigate them. But we have been so close to this project for so long that it is easy to overlook something that someone else with uncommitted eyes would see. That's why we asked for the peer review. Don't be disappointed in my answer. See it as an opportunity to see things we could have missed.
Title: Re: DIRECT v2.0
Post by: Jim on 05/20/2007 11:12 PM
Quote
shostetler - 20/5/2007  6:49 PM
 Granted the shuttle may have over extended it's use as it is aging significantly, but why doesn't NASA keep with the program as it knows works already and build on that?

It doesn't "work".  It wastes lift capability and it is too expensive and on and on.  And it is not safe as it should be
Title: Re: DIRECT v2.0
Post by: braddock on 05/20/2007 11:44 PM
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clongton - 20/5/2007  7:02 PM

Quote
Thomas ESA - 20/5/2007  11:41 AM

No. I want you to list as your key weaknesses. I am very disapointed with your reply, as it seems you don't know.
We know what we think our weaknesses are and are working to mitigate them. But we have been so close to this project for so long that it is easy to overlook something that someone else with uncommitted eyes would see. That's why we asked for the peer review. Don't be disappointed in my answer. See it as an opportunity to see things we could have missed.

Thomas is correct.  You need to be forthright about weaknesses you know about.  

It will also facilitate the feedback process better than "spot the weakness".

The whole point of Direct is to honestly examine the strengths and weaknesses of alternative options.
It is not (I hope) a sales pitch.
Title: Re: DIRECT v2.0
Post by: CFE on 05/21/2007 01:39 AM
I think that Jupiter's at a disadvantage from a safety standpoint due to the use of parallel staging.  Any SRB problem will snowball as did Challenger's.

At the same time, I think NASA exaggerates the inherent safety of the single-stick design on Ares I.  I skimmed the massive safety document that SAIC released in early 2006 which made the case for Ares I's safety.  Any crack in the propellant grain is going to accelerate the burn rate, possibly leading to a catastrophic failure.  If an O-ring burns through on Ares I, will the capsule still be able to make it to orbit?  Will the abort detection system be able to recognize the burn-through by the change in thrust and additional torques that will result?

The SAIC report made it clear that a catastrophic failure of Ares I's first stage is not survivable.  The report basically says that we should ignore that situation because it's so rare.  I suspect that it might be a bit more common than the statistics may let on.  At least with a liquid-fueled first stage, most failure modes develop slowly enough that the abort system would have time to activate.  And if NASA needs to add Castor SRM's to Ares I, the safety numbers for Ares I will take another hit.

I suspect that Jupiter's crew would be able to survive a Challenger-type scenario.  Michael Smith obviously saw that his tank pressure readings were dropping off before the main fireball was seen on video.  An automated abort system would likely be quick enough to detect the failure of the hydrogen tank and fire the escape tower.  Even if the explosion occurred too quickly to trigger an abort, the capsule could be strong enough to survive the initial explosion, as did Challenger's crew compartment.  The difference is that the capsule would have parachutes and other recovery systems, so it won't slam into the ocean at >200 mph.
Title: Re: DIRECT v2.0
Post by: Jim on 05/21/2007 01:53 AM
Quote
CFE - 20/5/2007  9:39 PM

I think that Jupiter's at a disadvantage from a safety standpoint due to the use of parallel staging.  Any SRB problem will snowball as did Challenger's.

This is not an issue.   Only if the crew capsule is down on the same level
Title: Re: DIRECT v2.0
Post by: pippin on 05/21/2007 08:31 AM
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CFE - 21/5/2007  3:39 AM

I suspect that Jupiter's crew would be able to survive a Challenger-type scenario.  Michael Smith obviously saw that his tank pressure readings were dropping off before the main fireball was seen on video.  An automated abort system would likely be quick enough to detect the failure of the hydrogen tank and fire the escape tower.  Even if the explosion occurred too quickly to trigger an abort, the capsule could be strong enough to survive the initial explosion, as did Challenger's crew compartment.  The difference is that the capsule would have parachutes and other recovery systems, so it won't slam into the ocean at >200 mph.

You definitely have to trigger an abort, or your chutes will not be usable (abort system is in the way). However, the abort system might even be able to work it's way out of an explosion, if the capsule is rubust enough.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/21/2007 02:45 PM
That would be quite a pressure situation.  If you see one reading dropping off do you assume a major problem or do you think maybe its instrumentation.   If you abort & its just instrumentation that’s one expensive abort.    If you had a second symptom, an unexpected noise perhaps, then you would know its time to abort.  In that situation you only have a couple of seconds to make that decision.  I guess it’s a matter of training.  I am sure they will be well versed in what conditions warrant an abort.
If you are the pilot you are going to put your crews safety first.
Title: Re: DIRECT v2.0
Post by: Jim on 05/21/2007 04:08 PM
Quote
veedriver22 - 21/5/2007  10:45 AM

That would be quite a pressure situation.  If you see one reading dropping off do you assume a major problem or do you think maybe its instrumentation.   If you abort & its just instrumentation that’s one expensive abort.    If you had a second symptom, an unexpected noise perhaps, then you would know its time to abort.  In that situation you only have a couple of seconds to make that decision.  I guess it’s a matter of training.  I am sure they will be well versed in what conditions warrant an abort.
If you are the pilot you are going to put your crews safety first.

There are automatic aborts without crew intervention.
Title: Re: DIRECT v2.0
Post by: clongton on 05/21/2007 04:26 PM
Quote
veedriver22 - 21/5/2007  10:45 AM

That would be quite a pressure situation.  If you see one reading dropping off do you assume a major problem or do you think maybe its instrumentation.   If you abort & its just instrumentation that’s one expensive abort.    If you had a second symptom, an unexpected noise perhaps, then you would know its time to abort.  In that situation you only have a couple of seconds to make that decision.  I guess it’s a matter of training.  I am sure they will be well versed in what conditions warrant an abort.
If you are the pilot you are going to put your crews safety first.
Catastrophic abort scenarios happen too fast for the pilot to respond. In any such condition, the abort sequence will be triggered automatically. Cascading events that can lead to the self-destruction of the launch vehicle happen in milliseconds and follow an identifiable sequence of events, all programmed in the flight computers. The abort sequence initiation programs could recognize them and respond before the pilot was even aware of the condition.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/21/2007 07:15 PM
Quote
Thomas ESA - 18/5/2007  4:55 AM

Have you confidently identified your key weaknesses? This is important. Direct V1 failed to and was informed of it. Direct V2 needs to understand where it could be dismissed and already have alternatives/answers.

Missed your previous post Tom, apologies.   While I agree with Kaputnic saying it is really for others to identify, I will put some thoughts together here anyway for all to see.

The key weaknesses are programmatic.   Ares-I has momentum currently within NASA, and getting NASA to turn that momentum around is only going to be possible in one of two ways:-

a) Internally driven change from the top - Griffin/Horowitz in particular.   I rate this as "unlikely" because Ares-I is the "Scotty Rocket".
b) Externally driven by Congress, probably resulting in NASA's current administration digging their heels in and then being forced out.   Not my personal preference, but I figure it is "more likely" given the personal preferences of Griffin/Horowitz.

The other category A critical weakness which we have is whether the EDS will ever be built or not.   On the current plan, there is a major concern that we will get the first vehicle (Ares-I) and then NASA' budget will be cut and we will never get the second vehicle.   While DIRECT's first vehicle is clearly the backbone needed to enable all of the Lunar missions later, we still need an EDS - which is going to be a seriously expensive piece of hardware whether it flies Ares or Jupiter.   If it is cancelled by a future government, it is still a major problem.


From a technical perspective the primary weakness in the entire system is not so obvious.   I believe that the use of highly toxic perchlorate in the SRB's is an issue that the EPA will turn its attention toward at some point in the near future and could cause the SRB's to be replaced.   This issue is far more likely to occur faster if a Democrat  is elected to the Oval Office next.   This issue affects DIRECT and Ares alike.   Liquid boosters (recoverable or not) are the ultimate solution to this, but ATK won't support that.   NASA currently has no money to develop liquid boosters while also building Ares-I and Ares-V.   DIRECT saves the entire development costs for the Ares-V program, so would have sufficient budget available to solve this issue.

Being brief, the technical breakdown of mean LOM contributors for a Jupiter-120 CLV flight is approximately thus:-

70% - Main Propulsion Systems (2 x RS-68 "Standard")
14% - RSRB (2x 4-segment)
8% - Spacecraft Adapter
8% - Other

Overall LOM is approximately 1 in 1,400.


From a reliability perspective, the 4-segment SRB has flown successfully 182 times since Challenger. The 5-segment SRB has never yet flown, let alone manned.   We have little to no idea of how safe it is going to be, especially given the radically different loads it will experience on Ares-I flights.   The twin-SRB configuration does add the "one doesn't start" risk, to crew flights but there are sufficient, already well proven on STS, backup systems to reduce this risk to very manageable levels.   NASA's current estimates for this form of failure are in the order of 1 in 280,000 flights - and this also effect the Ares-V - which will ultimately fly people too.   Ares-I's precise TVC control during ascent is a far bigger problem.

The J-2X is loosely based on the J-2S, neither of which have ever flown.   They in turn are based on the Apollo J-2, which suffered three in-flight failures in its 87 flight history.   If this engine does not start on Ares-I, it guarantees an abort scenario for the Crew - which itself is a dangerous event carrying many life-threatening risks and is something which ought to be avoided unless absolutely necessary.   Jupiter-120 ground-launches all engines, which is a major safety benefit which Shuttle has today.

So far the RS-68 has a perfect, albeit short, flight record.   Operating at a nominal 100% maximum power setting on Jupiter though, it is expected to be twice as reliable as the 106% power setting NASA is specifying for all Ares-V engines.


From a safety perspective, we are a match for Ares-I.   We have a different list of pro's and con's, but ultimately we're about equal.   While we have more engines and staging events than Ares-I, we have main engine-out capability for most of the flight, which can save missions and avoid aborts entirely.   We also have no air-start engines on Crew missions in the early phases of the program - allowing a major body of knowledge to be built with the new systems before ever risking crews to J-2X's which don't start.

Jupiter does not use the Orion's Service Module to reach orbit.   This reduces the number of times the OME engine must fire to accomplish a mission.   Ares-I requires a long firing to complete ascent to space, then two additional, shorter, burns to increase altitude to it's final stable orbit.   Jupiter requires only one single, short, burn of the SM to circularize the CEV's orbit.   No long burn is required during ascent.   This reduces the critical number of burns on the engine which will ultimately save all crews returning from the Moon.   Putting additional requirements on this engine is a potentially deadly mistake.

Jupiter also places the Crew Module a considerable extra distance away from the engines, and also away from the center-line of flight for the Crew Module - both of which actually benefit safety.   We are also using all-proven existing engines, not modified/updated ones, which means we start the program with greater safety margins because we have a large body of flight knowledge before the first flight.

We also have performance margin on our side - which makes everything a lot easier.   The spacecraft can be made from simpler, less exotic, less costly materials.   With more performance, more safety equipment can be utilized also.   For example, a new range-safety system could be flown designed to specifically stop any SRB from ever 'following' an Orion during an abort, even if it weighs quite a bit.   This is a real-world potential problem with Ares-I right now.   It will also be an issue for Ares-V and Jupiter crewed flights.   But Jupiter is the only system which offers surplus performance on all Crew flights, so additional systems (like those described in previous comments here) could be implemented.   We have 20-25 tons of surplus performance available on every CEV flight to "play with".   I'm sure there are many things which we have not imagined yet, which can be done with this extra performance but which Ares-I will never allow.


From an implementation perspective, we re-use more of the existing Shuttle manufacturing and processing hardware in use today, so again, we are in a stronger position than either Ares-I or Ares-V.


Politically speaking, by keeping as close to STS as possible, yet achieving all the performance objectives of the VSE, we guarantee the workforce far more effectively than Ares-I and Ares-V do.


In short, *ALL* of our weaknesses are ones shared by the Ares vehicles, we are using similar systems after all.   Typically though, we reduce the number of them.   Additionally, we are using immediately available assets (which are already proven) instead of new or re-worked ones and we do so in a simpler configuration too, all of which reduce the risks to more reasonable levels.

Ross.
Title: Re: DIRECT v2.0
Post by: Bill White on 05/21/2007 08:05 PM
After reading this,

Quote
kraisee - 21/5/2007  2:15 PM

The key weaknesses are programmatic.   Ares-I has momentum currently within NASA, and getting NASA to turn that momentum around is only going to be possible in one of two ways:-

a) Internally driven change from the top - Griffin/Horowitz in particular.   I rate this as "unlikely" because Ares-I is [paraphrase: a favorite of Scott Horowitz].
b) Externally driven by Congress, probably resulting in NASA's current administration digging their heels in and then being forced out.   Not my personal preference, but I figure it is "more likely" given the personal preferences of Griffin/Horowitz.

and especially this:

Quote
From an implementation perspective, we re-use more of the existing Shuttle manufacturing and processing hardware in use today, so again, we are in a stronger position than either Ares-I or Ares-V.

Politically speaking, by keeping as close to STS as possible, yet achieving all the performance objectives of the VSE, we guarantee the workforce far more effectively than Ares-I and Ares-V do.


A thought came to me about holding a "Direct-V2.x conference" in Washington combined with visits to Capitol Hill in the manner of the Moon-Mars Blitz. Hand deliver DirectV2.0 briefing packets to as many congressional offices as could be arranged.

2008 shall be a very volatile election season for Congress as well as the White House and therefore you might find a few politicians willing to carry your flag for you.

Now, that may be surgery with a Sawzall rather than a scalpel but it would garner attention.

= = =

PS -- I'd attend and carry Direct-V2.x briefing packets through the halls of the Congressional office buildings.


Title: RE: DIRECT v2.0
Post by: Chris Bergin on 05/21/2007 08:09 PM
Jumping in for a second. I don't want to see things like "Scotty Rocket" etc. It's starting to sound a bit derogatory of Mr Horowitz, and I'm not going to stand for that here.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/21/2007 08:15 PM
Just to clarify, the name "Scotty Rocket" isn't mine, and is not derogatory.

It is from
an article by Guy Gugliotta of the Washington Post and is the result of an interview with Scott "Doc" Horowitz himself.

Ross.
Title: Re: DIRECT v2.0
Post by: clongton on 05/21/2007 08:40 PM
Quote
kraisee - 21/5/2007  4:15 PM

Just to clarify, the name "Scotty Rocket" isn't mine, and is not derogatory.

It is from an article by Guy Gugliotta of the Washington Post and is the result of an interview with Scott "Doc" Horowitz himself.

Ross.
I've seen the Washington Post Article before, and what impresses me about it is not the term "Scotty Rocket", but how dedicated this man is to the space program. It's as if doing this is a passion that drives his every breath. This man lives the dream. He was fortunate to be able to actually do the things required that made his dreams of working with space flight come true; something most people can only dream about. The man is a brilliant engineer and designer. He has proven that time and again. He works extremely hard and his dedication to the cause of human spaceflight is beyond reproach.

Whatever one may think of the Ares-I rocket, it is not a pie-in-the-sky idea. Barring some unforseen insurmountable difficulty, it can work. It is based on solid physics and engineering. We, the proponents of the Direct architecture, go out of our way to NOT attack the Ares-I and would appriciate others doing the same.

We do, on the other hand, believe we have a proposal that will serve the VSE better than the architecture which depends on the Ares-I. Time will tell us if we are right or not. Like I said above, one may or may not like the Ares-I. I do like it. I just don't believe it is the right vehicle for this specific job, for a variety of reasons.

Dr Horowitz, on the other hand, is a man I admire for his skill, intelligence, insight and having the drive to pursue his dream by whatever avenues open to him, and when there are none, he makes them. In this, he is an example to all of us.
Title: Re: DIRECT v2.0
Post by: on 05/21/2007 09:01 PM

Quote
Bill White - 21/5/2007  3:05 PM A thought came to me about holding a "Direct-V2.x conference" in Washington combined with visits to Capitol Hill in the manner of the Moon-Mars Blitz. Hand deliver DirectV2.0 briefing packets to as many congressional offices as could be arranged.  2008 shall be a very volatile election season for Congress as well as the White House and therefore you might find a few politicians willing to carry your flag for you.  Now, that may be surgery with a Sawzall rather than a scalpel but it would garner attention.  = = =  PS -- I'd attend and carry Direct-V2.x briefing packets through the halls of the Congressional office buildings.  

This is the "frontal assault" approach I was indirectly referring to. Staged appropriately and with appropriate news media present, it can be *very effective*. It's also very hard to ignore. Also very painful for an administrator when a project has had a shortfall, because the press has a tendency to smell blood in the water ... About as polite and subtle as a sledgehammer to the head, but ...
 

Title: Re: DIRECT v2.0
Post by: clongton on 05/21/2007 09:08 PM
Quote
nobodyofconsequence - 21/5/2007  5:01 PM

Quote
Bill White - 21/5/2007  3:05 PM A thought came to me about holding a "Direct-V2.x conference" in Washington combined with visits to Capitol Hill in the manner of the Moon-Mars Blitz. Hand deliver DirectV2.0 briefing packets to as many congressional offices as could be arranged.  2008 shall be a very volatile election season for Congress as well as the White House and therefore you might find a few politicians willing to carry your flag for you.  Now, that may be surgery with a Sawzall rather than a scalpel but it would garner attention.  = = =  PS -- I'd attend and carry Direct-V2.x briefing packets through the halls of the Congressional office buildings.  

This is the "frontal assault" approach I was indirectly referring to. Staged appropriately and with appropriate news media present, it can be *very effective*. It's also very hard to ignore. Also very painful for an administrator when a project has had a shortfall, because the press has a tendency to smell blood in the water ... About as polite and subtle as a sledgehammer to the head, but ...
 

Better off to let the ongoing efforts proceed. A frontal assault type of action would be counter-productive at this point. Remember, this is not an "us vs. them" type of thing. We all want the same thing - a sustainable resumption of manned spaceflight ASAP, a return to the moon and on to Mars. Let diplomacy have its chance to work. There is no need to "rush off to war". An embarrassed person is more likely to defend entrenched positions than they are to be open to examining reasonable alternatives. Let the on-going efforts have their chance, undistracted.
Title: Re: DIRECT v2.0
Post by: Bill White on 05/21/2007 09:10 PM
Quote
nobodyofconsequence - 21/5/2007  4:01 PM

Quote
Bill White - 21/5/2007  3:05 PM A thought came to me about holding a "Direct-V2.x conference" in Washington combined with visits to Capitol Hill in the manner of the Moon-Mars Blitz. Hand deliver DirectV2.0 briefing packets to as many congressional offices as could be arranged.  2008 shall be a very volatile election season for Congress as well as the White House and therefore you might find a few politicians willing to carry your flag for you.  Now, that may be surgery with a Sawzall rather than a scalpel but it would garner attention.  = = =  PS -- I'd attend and carry Direct-V2.x briefing packets through the halls of the Congressional office buildings.  

This is the "frontal assault" approach I was indirectly referring to. Staged appropriately and with appropriate news media present, it can be *very effective*. It's also very hard to ignore. Also very painful for an administrator when a project has had a shortfall, because the press has a tendency to smell blood in the water ... About as polite and subtle as a sledgehammer to the head, but ...
 


Also, since DirectV2.x is actually a tweaking of ESAS rather than a scrapping of ESAS, as per this comment from clongton:

Quote
Whatever one may think of the Ares-I rocket, it is not a pie-in-the-sky idea. Barring some unforseen insurmountable difficulty, it can work. It is based on solid physics and engineering. We, the proponents of the Direct architecture, go out of our way to NOT attack the Ares-I and would appriciate others doing the same. We do, on the other hand, believe we have a proposal that will serve the VSE better than the architecture which depends on the Ares-I.

I could foresee one or another Presidential candidates taking interest as an opportunity to create a sliver of daylight between current policy and proposed policy while remaining essentially loyal to the VSE vision.

And that is the political genuis of Direct-V2.x, in my spectator's opinion. Well done.
Title: Re: DIRECT v2.0
Post by: Bill White on 05/21/2007 09:13 PM
Quote
clongton - 21/5/2007  4:08 PM

Quote
nobodyofconsequence - 21/5/2007  5:01 PM

Quote
Bill White - 21/5/2007  3:05 PM A thought came to me about holding a "Direct-V2.x conference" in Washington combined with visits to Capitol Hill in the manner of the Moon-Mars Blitz. Hand deliver DirectV2.0 briefing packets to as many congressional offices as could be arranged.  2008 shall be a very volatile election season for Congress as well as the White House and therefore you might find a few politicians willing to carry your flag for you.  Now, that may be surgery with a Sawzall rather than a scalpel but it would garner attention.  = = =  PS -- I'd attend and carry Direct-V2.x briefing packets through the halls of the Congressional office buildings.  

This is the "frontal assault" approach I was indirectly referring to. Staged appropriately and with appropriate news media present, it can be *very effective*. It's also very hard to ignore. Also very painful for an administrator when a project has had a shortfall, because the press has a tendency to smell blood in the water ... About as polite and subtle as a sledgehammer to the head, but ...
 

Better off to let the ongoing efforts proceed. A frontal assault type of action would be counter-productive at this point. Remember, this is not an "us vs. them" type of thing. We all want the same thing - a sustainable resumption of manned spaceflight ASAP, a return to the moon and on to Mars. Let diplomacy have its chance to work. There is no need to "rush off to war". An embarrassed person is more likely to defend entrenched positions than they are to be open to examining reasonable alternatives. Let the on-going efforts have their chance, undistracted.

Fair enough -- nothing like this should happen without the blessing of the Direct team.
Title: Re: DIRECT v2.0
Post by: on 05/21/2007 09:25 PM

Quote
Bill White - 21/5/2007  4:10 PM I could foresee one or another Presidential candidates taking interest as an opportunity to create a sliver of daylight between current policy and proposed policy while remaining essentially loyal to the VSE vision.

Understand your enthusiasm, but it would be unwise for any such to do so - they run the unnecessary risk of ridicule by the Sensenbrunner types in Congress, for little gain.

Better chance for advantage is in used as collateral for the "budgetary chicken" going on over Shuttle RTF rebudgetting/reimbursement. You get the Rep's in certain districts yelled at by certain constituents, and then they yell at the administration, who eventually has to choose its battles and yield when appropriate.

Title: Re: DIRECT v2.0
Post by: mmaroti on 05/21/2007 09:54 PM
Quote
clongton - 21/5/2007  4:08 PM
Better off to let the ongoing efforts proceed. A frontal assault type of action would be counter-productive at this point. Remember, this is not an "us vs. them" type of thing. We all want the same thing - a sustainable resumption of manned spaceflight ASAP, a return to the moon and on to Mars. Let diplomacy have its chance to work. There is no need to "rush off to war". An embarrassed person is more likely to defend entrenched positions than they are to be open to examining reasonable alternatives. Let the on-going efforts have their chance, undistracted.

Search your own experiences: how many times did you see an administrator give up a plan that is 1) technically feasible, 2) already in the works, 3) was heavily pushed by the leader's group, 4) blessed by  accounting, 5) but in certain aspects worse than another idea put forward by an outsider.

Get real! Non-ideal solutions are pushed through and ego wins against reason in almost all cases! If the administrator would reconsider (after so heavily invested in his own design) then he would just prove his incompetence! There is absolutely zero of that! The nasa administration desperately NEEDS A REASON to adopt Direct 2.0, and Congress is the only and ultimate reason (other than the president)! You better wait till more cuts are announced (or no raise is given), then build up a momentum with the media and get sided with a few congressman.

Miklos
Title: Re: DIRECT v2.0
Post by: kraisee on 05/21/2007 10:31 PM
Chuck is absolutely correct.   This is not, and never has been, an "Us vs. Them" proposal.   We just see a very serious danger that NASA is going to get stuck with nothing but an EELV class launch vehicle, and a budget which won't support the Ares-V at all - at which point we all lose the moon.   This would effectively cede the American superiority in space to someone else - probably China.

We don't see any advantages in NASA pursuing the Ares-I approach if the goal is to get America back to the moon in the shortest, most fiscally responsible manner possible, while realistically doing so within the politico-economic climate which NASA finds itself in today (think "workforce retention").

Spending big bucks just to building another EELV-class vehicle and then waiting half a decade for the heavy lift capability to follow it is massively politically risky, is sub-optimally uses the limited funds available to NASA, and creates a situation where NASA could be left with only a half-completed plan and no budget to fix it.

Jupiter allows Ares-V to still be made, and most importantly protects all of our goals even if Congress never funds the Ares-V.

Ross.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/21/2007 10:58 PM
If you try to apply pressure outside of NASA (congressmen, etc.) you are in effect declaring war.   That a pretty risky way to try & promote it.
The only realistic way to promote it is by working with the decision makers within (as much as possible).   That will put direct in the best position of opportunity if there are major problems with Ares or major funding cutbacks.   The tough part of that is the more time that passes and contracts are signed, it becomes more and more entrenched.    But maybe you could send one copy to G.W.  :)
Title: RE: DIRECT v2.0
Post by: publiusr on 05/21/2007 11:15 PM
Quote
kraisee - 16/5/2007  4:25 PM

The same basic concept was again proposed in 1991 as the National Launch System or NLS (image below, Credit: Astronautix.com).   It was a joint program between NASA and USAF.  

Ross.

I remember that (ALS/NLS). I think it would be smart to call it Ares Ib. Go with the flow, lets forget the ATK bashing and say--

"look, we can have a larger Orion, and for every capsule ATK sells two solids not just one per mission. Also, we will take those rail-damaged SRBs off your hands--and how-about we use them in ground tests, or in a prototype Direct if they aren't in too bad shape? Call it Ares IB. Also at a later date it might be filled with kero and RD-180s used for the Atlas NOVA concept for true Ares V performance and a good hydrogen upper stage?"

It couldn't hurt to ask...


It might be interesting to see a hydrogen only Direct LV for crew lift with a kerosene Atlas/NOVA--Direct for the actual HLLV.

Thw two stacks would seem similar...thus the ET width core could have different propellants...
Title: Re: DIRECT v2.0
Post by: MySDCUserID on 05/21/2007 11:16 PM
Quote
veedriver22 - 21/5/2007  5:58 PM

If you try to apply pressure outside of NASA (congressmen, etc.) you are in effect declaring war.   That a pretty risky way to try & promote it.
The only realistic way to promote it is by working with the decision makers within (as much as possible).   That will put direct in the best position of opportunity if there are major problems with Ares or major funding cutbacks.   The tough part of that is the more time that passes and contracts are signed, it becomes more and more entrenched.    But maybe you could send one copy to G.W.  :)

I heavily support going straight to congressmen about this.  That is what they are there for.  They are our representatives.  I highly doubt the upper layers of management within NASA have not heard of DIRECT by now.  There's little possibility, IMHO, that you will be able to change their minds.  Congress, however, would have some influence.  The news media should also be asked to do an investigative report on this.  Start by letting the local NASA center news outlets report on it, such as Florida Today or the Houston Chronicle.
Title: Re: DIRECT v2.0
Post by: CFE on 05/21/2007 11:19 PM
When John Houbolt and his allies pushed Lunar Orbit Rendezvous, they did so by working within the confines of the agency, and not by taking their fight to Congress or the media.  The approach has worked before, and it can work again.  It will take a bit of internal persuasion to make the agency realize that Ares I will not fall within the scope of NASA's existing or foreseeable budgets.  Frankly, the "DIRECT vs. Ares" debate is too technical for the mainstream media to get excited about, and Congress is unlikely to micromanage NASA by dictating a launch vehicle to them.
Title: Re: DIRECT v2.0
Post by: publiusr on 05/21/2007 11:23 PM
I did contact Bill Richardsons office. At best, lets hope he is Hilary's VP, or Obama's...

Here is hoping Brownback or Duncan Hunter pulls some upsets, but I'm really a Kyl fan these days...
Title: Re: DIRECT v2.0
Post by: MySDCUserID on 05/21/2007 11:51 PM
Quote
CFE - 21/5/2007  6:19 PM

When John Houbolt and his allies pushed Lunar Orbit Rendezvous, they did so by working within the confines of the agency, and not by taking their fight to Congress or the media.  The approach has worked before, and it can work again.  It will take a bit of internal persuasion to make the agency realize that Ares I will not fall within the scope of NASA's existing or foreseeable budgets.  Frankly, the "DIRECT vs. Ares" debate is too technical for the mainstream media to get excited about, and Congress is unlikely to micromanage NASA by dictating a launch vehicle to them.

Different times, different people, different culture, different program.  

Houbolt was faced with the simple problem of even getting the word out to those who neededed to hear it let alone getting people to accept it.  Houbolt had to physically get hard copies of his report into the hands of those with influence.  It is not like today, where many industry experts and employees, and well educated space enthusiasts are able to get their message across through the internet.  NASA management has already acknowledged that they are aware of online "armchair rocket scientists" and alternative ideas, and the blatantly push them to the side and move forward with Ares I.  

Also, the media does not need to get into the real indepth engineering details.  It is fairly obvious to even the non-engineer that DIRECT and/or EELV are better alternatives to Ares I.  An investigative report type of story would suffice.
Title: Re: DIRECT v2.0
Post by: on 05/22/2007 03:17 AM

Quote
MySDCUserID - 21/5/2007  6:51 PM  Different times, different people, different culture, different program.

   Houbolt was faced with the simple problem of even getting the word out to those who needed to hear it let alone getting people to accept it.  Houbolt had to physically get hard copies of his report into the hands of those with influence.  It is not like today, where many industry experts and employees, and well educated space enthusiasts are able to get their message across through the internet.  NASA management has already acknowledged that they are aware of online "armchair rocket scientists" and alternative ideas, and the blatantly push them to the side and move forward with Ares I.    

Also, the media does not need to get into the real indepth engineering details.  It is fairly obvious to even the non-engineer that DIRECT and/or EELV are better alternatives to Ares I.  An investigative report type of story would suffice.

Very true and a correct assessment. Houbolt was struggling for recognition. That isn't the issue here - its "bloody mindedness".

As to what to do - I won't recommend a specific action.  

Title: Re: DIRECT v2.0
Post by: rumble on 05/22/2007 03:27 AM
Quote
CFE - 21/5/2007  6:19 PM

When John Houbolt and his allies pushed Lunar Orbit Rendezvous, they did so by working within the confines of the agency, and not by taking their fight to Congress or the media.  The approach has worked before, and it can work again.  It will take a bit of internal persuasion to make the agency realize that Ares I will not fall within the scope of NASA's existing or foreseeable budgets.  Frankly, the "DIRECT vs. Ares" debate is too technical for the mainstream media to get excited about, and Congress is unlikely to micromanage NASA by dictating a launch vehicle to them.
There is something to be said of someone within the organization handing a hardcopy proposal/presentation/white-paper/whatever to a senior person within the organization.

I wonder if John Young would be willing to step forward with it?  hmmm
Title: Re: DIRECT v2.0
Post by: kraisee on 05/22/2007 06:22 AM
My comments in this particular post are my personal thoughts on this matter and may not represent the opinions of other members of the DIRECT team.   Please bear that in mind as I continue...

My own opinion is that Griffin & co are not stupid.   They are extremely bright and capable people, and I'm actually a bit of a closet fan.   I think Ares-I is a mistake, because I see Ares-V being cancelled before it ever flies and the first vehicle being the only thing America will fly people on for the next two or three decades - and we need the first vehicle to be a heckuva lot more powerful than the EELV-class Ares-I.   That is what I sincerely believe the current plan has in store for all future generations of Americans.

I am an enthusiast of the VSE, the goal of reaching back towards the moon and going on towards Mars and hopefully beyond.   Before the tragic loss of Columbia and her crew, I didn't think I would ever get to see a human walk on any other planetary body in my lifetime - Apollo was of my Parents generation - its pure "history" to mine.

I think it would be criminally negligent to support a plan which risks this important future dream on the "hope" that the current American political system will remain stable enough to build multiple new launch vehicles over the better part of a 20 year period.   Is there anyone reading this who seriously thinks the current system is *that* stable?

I think that idea is simply barking mad, and I think Griffin, deep down, knows it is the most risky part of the entire endeavour he helms today.

As I say, I'm a fan and an enthusiast.   But he's the boss of a multi-billion dollar government program, funded by us, the tax-payers.   If he can, in good conscience, assure us that there is no risk of Ares-V being cancelled and the entire VSE being scuppered in the process, then I wish him the best.   But I don't think he can promise that, because I don't think he believes that himself.   I bet he's very concerned by that, because I'm sure he's smart enough to have identified that risk already, and I'm sure he knows its a major one.

If he has serious reservations on this critical issue, then he has an obligation to the next two generations of Americans, to make sure NASA is on the best path for the nation.   He needs to weigh the "wish" for Ares-I leading to Ares-V against the "risk" of only ever getting Ares-I and leaving the US with no true Heavy Lift capability (100 tons +) at all.

Only he can decide that.   We can't.

What our little team is trying to do with DIRECT is to clearly point out this risk being taken now, and identify a "general" alternative path which is still open.   After all, not one singe piece of new hardware has gone into production yet.   In fact, very little of the new hardware is currently being tested.   The vast majority of Ares-I and Ares-V systems are still nothing but virtual simulations on a computer.   Five years from now, it will be a different story.

I'm going to be very blunt, and not very charming, when I say that I fear that ego is playing a part in NASA's current plans.   Sorry, but that's my personal opinion and I am explicitly exercising my right to free speech when I say that.   I have my own considerable reservations about the motives surrounding the choice of the Ares-I's configuration.   Don't get me wrong, I don't actually think anyone is being "evil" or that NASA is the new "Conspiracies R Us" organization, but I do believe that personal preferences for one vehicle configuration on the part of some specific people at NASA have been the driving force behind the directions chosen.    Sometimes strong leadership from on top is a good thing (von Braun).   But equally, sometimes it can lead to disaster (Goldin).

In this specific case I think Ares-I is a very bad thing for Americas space program because it risks everything on a gamble that Ares-V will also be built and nothing will derail it over the next 12 years before it is ready.   My concern is exacerbated because other, far less risky options exist, which fulfil every single one of the requirements, but appear to be ignored or disqualified for, what I perceive as, unusual reasons.

I desperately hope I am wrong.   I hope there are no personal agendas at work and that deep knowledge, sound engineering and dutiful responsibility are really in the drivers seat.   Griffin certainly does seem to possess all those qualities, but this single decision seems, to me, to be outside of his normal modus operandi.   I am left unconvinced and very concerned.


The key issue is Griffin's legacy in the minds of future generations.   He will be remembered for either his successes or his failures, and with that, all of our dreams go too.

The shape of Griffin's legacy rests entirely upon whether the US reaches the moon by 2020 or not.   For me, that boils down even further to one simple issue:   Whether America ever gets a Heavy Lift Launch Vehicle (100 tons+) or not. Without that, we aren't likely to be going anywhere at all except Low Earth Orbit.   I see three possible legacy outcomes from where we sit today:-

1)   Griffin gambles that everything goes according to plan, that Ares-I becomes operational on-time and on budget, thus convincing Congress to fund the Ares-V.   Both are ultimately completed, broadly on budget, schedule and they do deliver the safety and performance requirements.   In this scenario, Griffin's legacy is a good one: "Griffin was the Administrator who re-created NASA afresh and got us exploring once again"

2)   Something goes wrong and either Ares-I or Ares-V never come to fruition.   Congress cancels the VSE because of any number of reasons such as political wrangling between the two major sides of the aisle, budgetary problems, safety problems, management screw-ups, higher government funding priorities (Social Security? War? Trade Deficit? Foreign Borrowing Deficit? Delete as applicable), or technical hurdles prove too much (cost, time or politics).   Whatever the reason, the gamble doesn't pay off because NASA stretched too far and something snapped.   The result is that Ares-I probably flies, but we lose Ares-V and that means we completely lose the ability to reach for the moon & Mars. Griffin's legacy in this scenario becomes that of " the Administrator who closed down the Shuttle and left us with only the ability to fly a capsule to LEO with no ability to do anything else".

3) NASA takes the bank shot while it is still early enough, and builds one vehicle which can do both LEO work and also works for all the heavy lifting necessary for Lunar work later.   Even in the worst possible case here, with just the Jupiter-120, a political climate which turns against the VSE can be ridden out until the climate becomes favourable for a new Lunar push.   The J-120 services LEO, but when the political winds are favourable, it easy scales to the J-232 again.   Even without 100 ton lift capability, a J-120 could *still* support a 3-launch Lunar mission without ever building a new EDS.   Man-rated versions of existing Centaur stages could be used instead.   Such a J-120"C" isn't as good as a full J-232, but would still guarantee us the moon even in event of the worst budget cuts and political bad will against NASA imaginable.   If political will and economics do remain good, we can still evolve J-120 into the Ares-V, and do so on the current timeline if circumstances permit, thus getting the best of all worlds.   But we *never* ***EVER*** risk losing the ability to go to the moon.   Ares-I does risk that.   Griffin's legacy is safeguarded from virtually any eventuality: "Griffin turned Shuttle into a new system which got us back to the moon and on to Mars because he recognized the dangers of an ever-tightening budget early enough and did something about it.   We always had a moon rocket, right from the start".


Griffin's legacy in the above scenarios, to me, also represents the hopes & dreams of every pro-space enthusiast I have ever met.   If his legacy fails, we all fall with it.   If his legacy shines, we all have a bright future.

I feel that the programmatic risks surrounding building Ares-V after Ares-I are being deliberately ignored, and downplayed.   I believe that any plan which does not specifically protect against negative political and economic changes over a two decade period is simply begging for catastrophe.

If Griffin's current plan goes wrong, his name will be cast into shadow for all of history, and his decisions will possibly be held, for all eternity, against the fact that a reasonable alternative was suggested and was ignored.

I don't think NASA's current plan is a wise route.   It risks all, when those risks are actually unnecessary.   That doesn't seem sensible to me.   I believe DIRECT offers a reasonable alternative which deletes this major program risk completely, guaranteeing that with the first LV, we can reach the moon whether we build a second vehicle or not.  And this vehicle actually offers some interesting improvements over the current plan as a side-effect.

It is ultimately Griffin's decision, and he is the person actually casting the dice in this gamble.   I hope, for all our sakes, he doesn't gamble and lose.   If I were him, I would choose the option which still works even if you roll snake-eyes.

Ross.
Title: Re: DIRECT v2.0
Post by: CFE on 05/22/2007 07:02 AM
Well put, Ross!  I think you've hit the nail on the head in regards to NASA.  Good people sometimes make bad decisions for reasons that seem somewhat logical, at least in their minds.

The only thing I think you've neglected is a possible scenario where NASA and Congress initially commit to Ares I, but that program gets delayed and eventually canceled due to shifting budget priorities.  Assume that there's a major political shift which leaves the states with major space interests (predominantly "red states") out in the cold.  Assume we get a congress or president who views the world as a zero-sum game, and thinks that space steals money from social programs.  Assume that Ares I is delayed beyond 2015, and even NASA's most diehard congressional backers begin to lose hope.

The odds are certainly stacked against Ares V, but I'd say it's only a 50-50 shot that Ares I flies to orbit.  Getting a manned Orion flight safely into orbit, as quickly as possible, should be NASA's number one priority.  Whether it's Jupiter 120 or Atlas V under that capsule is of less consequence.  Get SOMETHING flying to get your foot in the door, and win the support of congress and the American people.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/22/2007 07:19 AM
CFE, I doubt it would actually happen because that really would be catastrophic for the workforce retention goals which are Congresses primary interest.   If there were to be no Shuttle-derived launcher at all, there sure won't be any Shuttle-derived workforce being paid.

Congress has good reason to support NASA getting one shiny new launch vehicle, because Congress needs that.   But ***CONGRESS*** has no requirement at all for a second vehicle.

A second vehicle does not increase the workforce massively, so isn't a big issue for representatives of constituents.   A second vehicle is ***SOLELY*** a requirement for NASA and the VSE.   We aren't in a political fight for superiority against the "Ruskies" any more, so Congress has little interest beyond jobs programs.

Worse still, VSE was program originally sponsored by one political party.   That party's opponents are in the strong position these days, and look to be getting stronger almost every day at present.   Opponents will be numerous already simply due to party affiliations.

There are no negative "workforce retention" issues to cancelling Ares-V once Ares-I is flying.   But Ares-V requires a second round of investment measuring billions of dollars at a time when a lot of other issues will be tugging at the US Treasury's funding.

This is a very bad combination of circumstances IMHO, and I feel that anyone who ignores it does so at their peril.


And I agree.   One potential "abort scenario" which DIRECT offers the new program is the early man-rating of the existing RS-68 engine.   If the J-120 schedule were to slip too far, NASA would have the emergency option to pop a mostly un-fuelled 12 ton Orion up on a "quick'n'dirty" Delta-IV Medium in 2012/13/14 and rescue its political butt that way while the main vehicle is being finalized.   It's not ideal, but its certainly a potential option in the face of any serious political threats.   And again, no such backup is possible with Ares-I because it is an entirely proprietary system.

Ross.
Title: Re: DIRECT v2.0
Post by: JIS on 05/22/2007 08:34 AM
Quote
MySDCUserID - 22/5/2007  12:51 AM

NASA management has already acknowledged that they are aware of online "armchair rocket scientists" and alternative ideas, and the blatantly push them to the side and move forward with Ares I.  

Also, the media does not need to get into the real indepth engineering details.  It is fairly obvious to even the non-engineer that DIRECT and/or EELV are better alternatives to Ares I.  An investigative report type of story would suffice.

I agree this is not about engineering or science. Direct is about feeling.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/22/2007 01:41 PM
Ross,

Griffin and Horowitz have long made up their mind that this is the architecture they want and they will nail their careers on it. This is why they are currently crying wolf about the gap when it is clearly one of their own making given the choices they made. They also hope to make it a done deal by the time they leave in 2008. You need to concentrate your lobbying on the Democrat Presidential candidates and inform them completely and throroughly about DIRECT so that if one of them wins, which is more likely than not, they can appoint an administrator to carry DIRECT out. Lobby the Democrats in Congress next as they currently have the power and are more likely to buy into the lower cost of DIRECT whereas the Republicans will just follow Bush and his appointee Griffin's plan. They can perhaps set up a independent committee to double check ESAS given the changes in architecture since and the 3 year addition to the gap. Safe, Simple but Late, Costly, Inefficent and Inflexible and you have to spell this out about Ares I/V to those you lobby. Good luck :).
Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/22/2007 01:45 PM
Quote
JIS - 22/5/2007  9:34 AM

Quote
MySDCUserID - 22/5/2007  12:51 AM

NASA management has already acknowledged that they are aware of online "armchair rocket scientists" and alternative ideas, and the blatantly push them to the side and move forward with Ares I.  

Also, the media does not need to get into the real indepth engineering details.  It is fairly obvious to even the non-engineer that DIRECT and/or EELV are better alternatives to Ares I.  An investigative report type of story would suffice.

I agree this is not about engineering or science. Direct is about feeling.


It is actually about politics, unfortunately.
Title: Re: DIRECT v2.0
Post by: david-moon on 05/22/2007 02:30 PM
Getting back to the topic of weaknesses in the Direct V2.0 presentation, I see two that the Direct editors ought to consider.  Addressing the less important first:

It is not made as clear as it could be that the Jupiter-120 Crew Launch Vehicle has *no* second stage.  This is implied, and then is mentioned later, but in my opinion it should be stated up front that the 48 tons to LEO capability uses only the STS-derived tank and 4-segment solids; no upper stage.  This is an important schedule advantage and should not be buried.

More importantly, the obvious objection to J-120 as the Crew Launch Vehicle instead of Ares-1 is the cost per flight.  This has not yet been mentioned.  You have good arguments that the overall program cost of the VSE is less using Direct rather than Ares-1 and -5.  But the marginal cost of a Jupiter-120 flight is surely higher than the marginal cost of an Ares-1 flight, and this is an argument that you can bet will be used against Direct.  You need to discuss these costs explicitly, with the most accurate numbers you can come up with, and you need to argue why the higher marginal cost of a J-120 flight is not a problem and does not mean the overall spending level is higher.  This argument should be based on flight rates, expected number of years in service, and life cycle costs, including development, not on the greater capabilities of the J-120.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/22/2007 02:58 PM
I'm having a hard time understanding if Ares I really will have a lower cost per flight, all things considered.

Ares I as an ISS crew swap vehicle also requires several Progress launches to do the same job that the 120 would do on its own.

Ares I as a Moon rocket requires a much larger and more expensive companion than a 232.

Is that really a cheaper alternative even ignoring the development costs?
Title: Re: DIRECT v2.0
Post by: clongton on 05/22/2007 03:01 PM
Quote
david-moon - 22/5/2007  10:30 AM

Getting back to the topic of weaknesses in the Direct V2.0 presentation, I see two that the Direct editors ought to consider.  Addressing the less important first:

It is not made as clear as it could be that the Jupiter-120 Crew Launch Vehicle has *no* second stage.  This is implied, and then is mentioned later, but in my opinion it should be stated up front that the 48 tons to LEO capability uses only the STS-derived tank and 4-segment solids; no upper stage.  This is an important schedule advantage and should not be buried. ... (finance questions continue)
David; I'll address the first point:

On page 8 of the paper, it states in paragraph 2 "The first number represents the number of cryogenic stages used prior to Earth Orbit Insertion (EOI) ... The third number represents the number of engines on any upper stage - or '0' if no upper stage is to be flown".

In paragraph 3 it states "Thus a 'Jupiter-120' would be the designation for the initial variant, with one cryogenic stage, two main engines and no upper stage".

The variant designation number defines the number of stages to achieve orbit with the first number in the 3-digit designation. Thus a Jupiter-1xx has 1 main stage, a Jupiter-2xx has 2 main stages and a Jupiter-3xx would need 3 stages to reach orbit. A pair of solids is always assumed.

An important point to remember here is that the designation speaks to how many stages are used to achieve *ORBIT*. Any launch vehicle can carry an additional engine as part of the payload that is used *AFTER* orbit has been achieved, to continue the mission. Any such additional engines are not considered to be part of the launch vehicle. They belong to the Payload, not the launch vehicle.

In comparing the Jupiter-120 to the Ares-I, all Jupiter flight engines are ignited on the ground, no air start is required, while the Ares-I depends on the 2nd stage igniting at altitude.

I'll let Ross or Steve address the finances.
Title: Re: DIRECT v2.0
Post by: JIS on 05/22/2007 03:02 PM
Quote
Kaputnik - 22/5/2007  2:45 PM

Quote
JIS - 22/5/2007  9:34 AM

Quote
MySDCUserID - 22/5/2007  12:51 AM

NASA management has already acknowledged that they are aware of online "armchair rocket scientists" and alternative ideas, and the blatantly push them to the side and move forward with Ares I.  

Also, the media does not need to get into the real indepth engineering details.  It is fairly obvious to even the non-engineer that DIRECT and/or EELV are better alternatives to Ares I.  An investigative report type of story would suffice.

I agree this is not about engineering or science. Direct is about feeling.


It is actually about politics, unfortunately.

Presented Direct study is more about feeling. It doesn't present any technical or economical argument why the VSE architecture using alternative launcher should be cheaper than using Ares1 /Ares V. It's only about feeling.
I have the similar feeling that launcher using exactly the same SRBs as STS and RS-68 (from DIV) instead of J-2X could be available sooner than Ares 1 but it is somewhat irrelevant.
It doesn't project to cheaper alternative architecture of VSE at all.
VSE requires to finish ISS and retire STS by the end of 2010 and begin operation of the next space ship till 2015. The current architecture is well on track and so far the White House can be happy.
If DIRECT study is talking about alternative architecture with lower cost it's BS. I haven't seen any numbers confirming that. The only thing I've seen so far is a study of Shuttle derived family of launchers (omitting rumours proved false).
Choosing politic path to present this study is a wrong decision. The first DIRECT study already did a lot of damage to your cause. No politician can be sure whether the new DIRECT study could be crushed in the similar way to the previous one. They will be very cautious.
IMHO the right path would be to get reviewed all claims by independent experts. If you say that Jupiter can lift so many tons into LEO I don't believe you a word.
If you claim it saves so many billions $ I don't believe you.
Get sound names approving those numbers, somebody who can stand behind them and get them independently verified. If you won't be able to do that you have no chance to be taken seriously.
Title: Re: DIRECT v2.0
Post by: JIS on 05/22/2007 03:18 PM
Quote
Lee Jay - 22/5/2007  3:58 PM

I'm having a hard time understanding if Ares I really will have a lower cost per flight, all things considered.

Ares I as an ISS crew swap vehicle also requires several Progress launches to do the same job that the 120 would do on its own.

Ares 1 is not a crew vehicle. Orion is. I believe that Jupiter would be carying the same (similar) Orion as Ares 1 is.

Quote
Ares I as a Moon rocket requires a much larger and more expensive companion than a 232.

Is that really a cheaper alternative even ignoring the development costs?

I have a feeling that Jupiter 232 could be cheaper than Ares V indeed. However, it doesn't mean it's a better approach.
Title: Re: DIRECT v2.0
Post by: jongoff on 05/22/2007 03:48 PM
JIS,
Quote
Presented Direct study is more about feeling. It doesn't present any technical or economical argument why the VSE architecture using alternative launcher should be cheaper than using Ares1 /Ares V. It's only about feeling.

Maybe its because the economic arguments are so obvious that they don't have to be made?  I mean do you really need to spell out that not developing a 5-segment SRB is going to be cheaper than developing it?  Unless developing that 5-segment SRB has a zero or negative cost, not having to develop it will by definition be cheaper.  The same applies to a brand new 10m diameter core stage, qualifying the RS-68s for operating at 106%, developing two upper stage instead of one, making two sets of all-new launch infrastructure instead of making slight modifications to the existing hardware, etc.  I'm sure that Ross et al could try spelling out the savings more explicitly, but it should be blatantly obvious to anyone with a clue that not developing something will cost less to develop than developing it.

Quote
I have the similar feeling that launcher using exactly the same SRBs as STS and RS-68 (from DIV) instead of J-2X could be available sooner than Ares 1 but it is somewhat irrelevant.
It doesn't project to cheaper alternative architecture of VSE at all.

It doesn't conclusively prove that the life-cycle costs will be less, you're right, but it makes a darned strong argument even without going into the details.  In order for ESAS to be less expensive, Ares I has to be so much marginally cheaper than DIRECT that it can make up for all of the excess development costs, the two standing armies, and all the infrastructure modifications.  Ross could try to give more specific numbers, but once again, its bleedingly obvious to anyone with a clue that it's going to be almost impossible for Ares I/V, with all their new required technologies, all the different tank sizes etc, all the pad changes, all of the extra people to run both of them, to be cost competitive with a single, unitary launcher.  Maybe if Ares I could've used a stock, barely modified SRB with an upper stage that used an existing engine, but as it is almost every single piece of hardware on Ares I and V is brand new, with most of it only loosely derived from existing hardware.  If I saw an economic analysis that didn't show DIRECT winning handily, I'd be extremely suspicious of the assumptions and methodology.

Quote
VSE requires to finish ISS and retire STS by the end of 2010 and begin operation of the next space ship till 2015. The current architecture is well on track and so far the White House can be happy.

Um the original operational date for Ares I/Orion was supposed to be 2012, not 2015 (and sliding).  Nobody is happy with the ever-widening gap.  

Anyhow, I just wonder what planet you're on sometimes.

Ross et al could try to give specific numbers for costs, but that's probably the most dangerous thing they could do.  NASA is an expert at playing numbers games and assumptions, and it would be quite easy for them to tweak the assumptions until it made DIRECT look more expensive.  These are after all the guys who when doing ESAS decided to make the Atlas V derivative upper stages have twice the dry mass because they "couldn't make the numbers work", and who also doubled the development cost.  Ross et al may have no choice but to try and eventually publish firm budget numbers, but it should be so obvious that developing one new vehicle that requires the minimum number of pad changes, the minimum number of new engines, and the minimum number of new stages or tank sizes is going to be cheaper.

~Jon
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/22/2007 04:13 PM
Quote
JIS - 22/5/2007  8:02 AM

Quote
Kaputnik - 22/5/2007  2:45 PM

Quote
JIS - 22/5/2007  9:34 AM

Quote
MySDCUserID - 22/5/2007  12:51 AM

NASA management has already acknowledged that they are aware of online "armchair rocket scientists" and alternative ideas, and the blatantly push them to the side and move forward with Ares I.  

Also, the media does not need to get into the real indepth engineering details.  It is fairly obvious to even the non-engineer that DIRECT and/or EELV are better alternatives to Ares I.  An investigative report type of story would suffice.

I agree this is not about engineering or science. Direct is about feeling.


It is actually about politics, unfortunately.

Presented Direct study is more about feeling. It doesn't present any technical or economical argument why the VSE architecture using alternative launcher should be cheaper than using Ares1 /Ares V. It's only about feeling.
I have the similar feeling that launcher using exactly the same SRBs as STS and RS-68 (from DIV) instead of J-2X could be available sooner than Ares 1 but it is somewhat irrelevant.
It doesn't project to cheaper alternative architecture of VSE at all.
VSE requires to finish ISS and retire STS by the end of 2010 and begin operation of the next space ship till 2015. The current architecture is well on track and so far the White House can be happy.
If DIRECT study is talking about alternative architecture with lower cost it's BS. I haven't seen any numbers confirming that. The only thing I've seen so far is a study of Shuttle derived family of launchers (omitting rumours proved false).
Choosing politic path to present this study is a wrong decision. The first DIRECT study already did a lot of damage to your cause. No politician can be sure whether the new DIRECT study could be crushed in the similar way to the previous one. They will be very cautious.
IMHO the right path would be to get reviewed all claims by independent experts. If you say that Jupiter can lift so many tons into LEO I don't believe you a word.
If you claim it saves so many billions $ I don't believe you.
Get sound names approving those numbers, somebody who can stand behind them and get them independently verified. If you won't be able to do that you have no chance to be taken seriously.

NASA won’t be able to ignore the CBO and OMB this time around.

Jupiter family will be significantly less expensive to develop and operate than the Ares family and the Jupiter-120 is safer than the Ares I.

So in summary NASA will be in the position of defending the argument that we should spend more money, destroy more STS facilities, layoff more of the NASA workforce, risk schedule to more new technology, and take longer to achieve the VSE objectives all in order to field a less safe, more expensive and less flexible launch vehicle family.  Then again this is a government program so maybe all the above is a good thing.

When you have a train headed for a cliff there is never a bad time to apply the brakes.

NASA/ATK's Safe, Simple and Soon is now Dangerous, Complicated, and Never

The real Safe, Simple and Soon is DIRECT.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/22/2007 04:21 PM
JIS, the problem with the finances is that NASA has made everything ITAR over the last year, and I don't believe any of my colleagues wish to illegally place numbers in a public forum of any sort and break those sorts of export rules.   Don't expect our numbers until *after* NASA allows its own to be released publicly for critique.

However, the ESAS Report numbers *are* publicly available.   There is an ACI Draft of the ESAS which still includes the real numbers which was accidentally made available on NASAWatch a few years back.   It got pulled quickly, but not before some distribution took place.

In general terms, and given the changes to the vehicles along the way, comparing the findings of ESAS and the current "real numbers" , the ESAS ones are still in the right ballpark.

They also clearly demonstrate that a single LV-24/25 based design (closest to DIRECT, yet still more expensive due to the use of 3xSSME instead of 2xRS-68), flying a 2-launch approach, and using either an EOR-LOR or an LOR-only approach is cheaper than the 1.5 solution which was chosen to:

a) Implement a CLV in a speedy manner, and
b) To re-use the same vehicle, with an U/S to fly the bulk of necessary Cargo needed for Lunar missions.

I haven't played around with the ESAS numbers in quite a while, so forgive me, but it is going to take me time to extract all that data again, and to present it in a clear manner, to demonstrate all the cost comparisons accurately.

Be aware, right right from the start, that this will only be a 'guide' using 'old' numbers.   However, the comparison it creates is still ***proportionately*** correct.

If that is acceptable to you, I will put the time in and present it all.   So please let me know if that's "good enough" for us to use in this discussion, or not.   If it is not going to be, I won't waste time doing it.

Ross.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/22/2007 04:24 PM
Quote
JIS - 22/5/2007  9:18 AM

Quote
Lee Jay - 22/5/2007  3:58 PM

I'm having a hard time understanding if Ares I really will have a lower cost per flight, all things considered.

Ares I as an ISS crew swap vehicle also requires several Progress launches to do the same job that the 120 would do on its own.

Ares 1 is not a crew vehicle. Orion is. I believe that Jupiter would be carying the same (similar) Orion as Ares 1 is.

Sorry for my imprecise language.  I meant using Ares I to launch Orion as a means of performing the ISS crew swap would also require one or more other launches by some other system for ISS resupply, while Orion on a 120 would potentially allow for cargo to be brought up at the same time thus saving the cost of the resupply launch(es).  So the question in my mind is "is Ares I + Orion + resupply launch(es) cheaper than Jupiter 120 with equivalent resupply capability?".
Title: Re: DIRECT v2.0
Post by: Jim on 05/22/2007 04:37 PM
The cargo capability to ISS should not be used to sell this.  There is no additional components for this.

The stick, Orion and progress should be compared to Direct, Orion and progress
Title: RE: DIRECT v2.0
Post by: PMN1 on 05/22/2007 04:55 PM
Does China have the ability to build a vehicle in the 'Direct' class?
Title: Re: DIRECT v2.0
Post by: david-moon on 05/22/2007 05:08 PM
Quote
clongton - 22/5/2007  11:01 AM

David; I'll address the first point:

On page 8 of the paper, it states ....

That is precisely my point.  It should be on page 2, not delayed until page 8.  The details can wait until page 8, but a person who doesn't read that far should still get the point that there is no upper stage needed for crew launch.
Title: Re: DIRECT v2.0
Post by: clongton on 05/22/2007 05:09 PM
Quote
Lee Jay - 22/5/2007  12:24 PM
Quote
JIS - 22/5/2007  9:18 AM
Quote
Lee Jay - 22/5/2007  3:58 PM

I'm having a hard time understanding if Ares I really will have a lower cost per flight, all things considered.

Ares I as an ISS crew swap vehicle also requires several Progress launches to do the same job that the 120 would do on its own.
Ares 1 is not a crew vehicle. Orion is. I believe that Jupiter would be carying the same (similar) Orion as Ares 1 is.

Sorry for my imprecise language.  I meant using Ares I to launch Orion as a means of performing the ISS crew swap would also require one or more other launches by some other system for ISS resupply, while Orion on a 120 would potentially allow for cargo to be brought up at the same time thus saving the cost of the resupply launch(es).  So the question in my mind is "is Ares I + Orion + resupply launch(es) cheaper than Jupiter 120 with equivalent resupply capability?".
Lee Jay

I don't have cost figures in front of me but even without them, it's obvious that launching a single Jupiter-120 would cost less than launching a pair of Ares-I's. Plus the costs of launch vehicle development and infrastructure changes would need to be factored in and depriciated over some agreed upon length of time. Neither are free, but the Ares development costs would exceed the Jupiter development costs by an order of magnatude, and the same goes for the infrastruction changes - an order of magnatude more expensive for the Ares. The fixed costs for both vehicles would be similar so for comparison purposes, you could just eliminate them. It will cost much much more to put the first operational Ares on the pad than it will to put the first operational Jupiter on the pad, and take decades to even come close to offsetting the expenses of the Ares development and infrastructure costs.

The Jupiter is far, far less expensive, from a program viewpoint, than the Ares.

All that being said, we must note that there are no cargo cannisters developed for the Jupiter to accompany an Orion into orbit, so your premise of resupply being on the same LV as crew rotation is not baseline. To do that would require first and formost a decision by NASA that such a flight did not violate the CAIB recommendation (another thread on this forum) and then to develop the cargo cannisters - not inexpensive. Something like the ATV for example, but it would need to be developed. Then the costs for that would need to be factored in as well. It's not as simple as just filling the SA up with resupply provisions.
Title: Re: DIRECT v2.0
Post by: jongoff on 05/22/2007 05:23 PM
Smetch,
Quote
NASA won’t be able to ignore the CBO and OMB this time around.

Now CBO and OMB may be just the right audience to send this information to.   Next time they do an analysis, if they also compare DIRECT to the Ares I/V and it comes out anywhere near as good as I think it would, that would help your cause a lot.

~Jon
Title: Re: DIRECT v2.0
Post by: clongton on 05/22/2007 05:26 PM
Quote
david-moon - 22/5/2007  1:08 PM

Quote
clongton - 22/5/2007  11:01 AM

David; I'll address the first point:

On page 8 of the paper, it states ....

That is precisely my point.  It should be on page 2, not delayed until page 8.  The details can wait until page 8, but a person who doesn't read that far should still get the point that there is no upper stage needed for crew launch.
page 1 is the cover
page 2 is an overall introduction to the subject
page 3 & 4 discuss the architecture
page 5 - 7 talk about the STS hardware used for the architecture
page 8 is where the launch vehicle itself is introduced.

Direct is not about the rocket. The rocket is a tool.
It's about the whole architecture, and the rocket is only part of it.
Anyone who doesn't read the whole thing would quickly embarrass themselves with their posts because it would be obvious that they were speaking from uninformed opinion.

The paper is not that big, and a lot of it is interesting graphics. I've read articles in magazines that were longer than this.

The details of the rocket are presented in the proper place.
Title: Re: DIRECT v2.0
Post by: david-moon on 05/22/2007 05:30 PM
Quote
clongton - 22/5/2007  1:26 PM

The details of the rocket are presented in the proper place.

I am sorry that you are not willing to listen to comments from people who have not been deeply involved in this for a long time and are coming at it from a naive perspective.

I will shut up now.
Title: Re: DIRECT v2.0
Post by: clongton on 05/22/2007 05:42 PM
Quote
david-moon - 22/5/2007  1:30 PM

Quote
clongton - 22/5/2007  1:26 PM

The details of the rocket are presented in the proper place.

I am sorry that you are not willing to listen to comments from people who have not been deeply involved in this for a long time and are coming at it from a naive perspective.

I will shut up now.
Don't do that. Your comments and thoughts are equally as important as anyone else's.

I explained to you why the details you asked about were located where they are. Believe me, we went thru a lot of work to arrange everything into a product that would intellectually "flow", without making any one piece of the architecture be the star. We came to believe that putting the rocket in the front would detract from the rest of the paper. We couldn't make the rest of it flow that way. We did what we did, the way we did it, to create a "process" of thought, to lead to the rocket, so that by the time the reader gets to it, they already understand the reasoning behind why it is configured the way it is.

The thought process goes like this:

1. This is the situation
2. Here's an architecture that can address it
3. These are the advantages of this architecture
4. Here's what we already have that we can use so we dont have to make new stuff
5. This is the rocket we can build from those things
6. This is what we can do with that rocket

See how it flows logically from need to solution?
That's why things are where they are.
Title: Re: DIRECT v2.0
Post by: on 05/22/2007 07:52 PM

Quote
jongoff - 22/5/2007  12:23 PM  Smetch,
Quote
NASA won’t be able to ignore the CBO and OMB this time around.
 Now CBO and OMB may be just the right audience to send this information to.   Next time they do an analysis, if they also compare DIRECT to the Ares I/V and it comes out anywhere near as good as I think it would, that would help your cause a lot.  ~Jon

Correct. Particularly the CBO this time.

Congress is dubious (both sides!) of a bloody minded administrator, fearing they'll take the blame for signing off on an open-ended deal they'll be stuck with for a while. They wait-off expecting to see more of what they want to see (actually, DIRECT has what they want to see in an obvious way). From time to time, they beat him up with CBO arguments, and expect him to come back with better.

One side holds the agenda, the other wants to, and each fears losing the initiative means loss of control in dictating the whole deal. No one is particularly enthused by new voices because it upsets the game. However, when something forces the situation, all adapt with new accommodations quickly. 

Title: Re: DIRECT v2.0
Post by: Kaputnik on 05/22/2007 08:21 PM
I mentioned this earlier but I don't think it was addressed.
In terms of presentation, I think you might be making a mistake in boldly asserting the superior safety of DIRECT over Ares-1. Remember, NASA already evaluated these two concepts and came to a different conclusion. You could instead say that NASA's analysis is slipping out of date/relevance as designs progress; that the ESAS safety numbers for a DIRECT-type vehicle were still masssively better than historic LOM/LOC figures; and also you could more subtly list those reasons that make DIRECT (in your eyes) safer than Ares (i.e. that the hardweare has flight history, amnogst other issues).
The current layout just seems a bit... arrogant.
Title: Re: DIRECT v2.0
Post by: imcub on 05/22/2007 11:23 PM
Quote
Kaputnik - 22/5/2007  1:21 PM

I mentioned this earlier but I don't think it was addressed.
In terms of presentation, I think you might be making a mistake in boldly asserting the superior safety of DIRECT over Ares-1. Remember, NASA already evaluated these two concepts and came to a different conclusion. You could instead say that NASA's analysis is slipping out of date/relevance as designs progress; that the ESAS safety numbers for a DIRECT-type vehicle were still masssively better than historic LOM/LOC figures; and also you could more subtly list those reasons that make DIRECT (in your eyes) safer than Ares (i.e. that the hardweare has flight history, amnogst other issues).
The current layout just seems a bit... arrogant.

I went back and re-read the proposal and I have to agree with Kaputnik about references to safety.  If I remember things correctly (and I'm sure someone will correct me if I am not), isn't NASA is quoting ARES/Orion as a LOC at 2000:1?  On the face of things, that's better than the 1400:1 being listed on direct.  

Yes, I know ... ARES is no longer using 4 segment SRB or the SSME and that it is going to be all new components except the SRB casings and that really invalidates the 2000:1 numbers being quoted.  I know that, but I visit this site everyday.  The intended audience, the people with the power and influence that might be able to alter NASA's chosen path, probably do not know this.  If NASA says ARES is shuttle derived and the LOC is 2000:1 ... then that's what your typical non-space geek audience will believe.    So ... a little more depth about why the Direct LOC numbers are better than ARES might be in order ... just a suggestion.

Slightly off the track ... has NASA changed the LOC/LOM numbers since they changed to a 5 segment SRB and J-2?  I don't recall seeing anyting different.

PS - I love the Mike Griffin quote at the beginning of the proposal ... he was spot on that day.

Title: Re: DIRECT v2.0
Post by: Smatcha on 05/23/2007 12:25 AM
Quote
imcub - 22/5/2007  4:23 PM

Quote
Kaputnik - 22/5/2007  1:21 PM

I mentioned this earlier but I don't think it was addressed.
In terms of presentation, I think you might be making a mistake in boldly asserting the superior safety of DIRECT over Ares-1. Remember, NASA already evaluated these two concepts and came to a different conclusion. You could instead say that NASA's analysis is slipping out of date/relevance as designs progress; that the ESAS safety numbers for a DIRECT-type vehicle were still masssively better than historic LOM/LOC figures; and also you could more subtly list those reasons that make DIRECT (in your eyes) safer than Ares (i.e. that the hardweare has flight history, amnogst other issues).
The current layout just seems a bit... arrogant.

I went back and re-read the proposal and I have to agree with Kaputnik about references to safety.  If I remember things correctly (and I'm sure someone will correct me if I am not), isn't NASA is quoting ARES/Orion as a LOC at 2000:1?  On the face of things, that's better than the 1400:1 being listed on direct.  

Yes, I know ... ARES is no longer using 4 segment SRB or the SSME and that it is going to be all new components except the SRB casings and that really invalidates the 2000:1 numbers being quoted.  I know that, but I visit this site everyday.  The intended audience, the people with the power and influence that might be able to alter NASA's chosen path, probably do not know this.  If NASA says ARES is shuttle derived and the LOC is 2000:1 ... then that's what your typical non-space geek audience will believe.    So ... a little more depth about why the Direct LOC numbers are better than ARES might be in order ... just a suggestion.

Slightly off the track ... has NASA changed the LOC/LOM numbers since they changed to a 5 segment SRB and J-2?  I don't recall seeing anyting different.

PS - I love the Mike Griffin quote at the beginning of the proposal ... he was spot on that day.


Good points, we’ll sharpen our pencils on this in the AIAA paper.

Mike is spot on over 95% of time in what he says.  What he does is another thing altogether.

Here is what he said just four years ago bout ELV’s being used for the Crew.

“Many, if not most, unmanned payloads are of very high value, both for the importance of their mission, as well as in simple economic terms. The relevant question may be posed quite simplistically: What, precisely, are the precautions that we would take to safeguard a human crew that we would deliberately omit when launching, say, a billion-dollar Mars Exploration Rover (MER) mission? The answer is, of course, “none”. While we appropriately value human life very highly, the investment we make in most unmanned missions is quite sufficient to capture our full attention.” Testimony of Mike Griffin before the Space and Aeronautics Committee on Science May 8, 2003


Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/23/2007 01:15 AM
Of course, if the cost of launching a payload is substantially reduced, then it might make economic sense to not spend billions of dollars designing out the last microgram of mass.  It might make sense to design inexpensive payloads that fly on inexpensive rockets, with the understanding that there is a 1% or a 4% or whatever chance that the payload will be lost.  It's a reasonable engineering tradeoff.

You don't make that kind of tradeoff with people's lives.

Also, if we were to fuel things on orbit, the only real value of the fuel is its location; the intrinsic value of 100 mT of fuel and LOX is tens of thousands of dollars, which is, as Elon Musk put it, "an accounting error."


Edit to add:

I didn't really finish my thoughts here.  Here's the other half:

Existing launch systems tend to have a pretty poor reliability record, compared to what is acceptable for human risk.  For example, we've lost 2 Shuttles in just over 100 flights.  The record of the Delta family shows many failures over the years.  (The Atlas family has actually done a bit better, with >100 flights now with no failures.)

Given this, it is reasonable to go to extraordinary lengths to protect human launches, while it is reasonable to accept slightly greater risk for non-human launches.

For a concrete example, let's consider a manned lunar mission.  To launch the human beings, it makes sense to use a launch vehicle which has been highly verified, to minimize risk.  But, you might choose to launch the mission stack on a much bigger LV that's fairly new, and has only flown a couple times.

With this philosophy, I'd see something like the Atlas Phase II (or the existing Atlas 401 if you were to build a capsule smaller than Orion) for launching people.  You'd use the Phase II for humans after several cargo launches with it to verify that it's OK.  And the pattern of unmanned cargos it carries helps on an ongoing basis to improve the safety of human flights.

On the other hand, it's OK to launch the mission stack on a newly-developed Ares V.  Yes, the stack is very valuable, and you're going to do everything in your power to make sure that you don't lose it.  But, ultimately, it is more acceptable to lose that flight than it is to lose a crew.

Now, I'm deliberately not using DIRECT in this example, because I want to keep the philosopy discussion distinct from DIRECT.   In the case of DIRECT, I think that the Jupiter 120 is an OK approach to launching people.  But only  OK; I think (my very uninformed opinion) that Atlas has an edge over the Jupiter because of its track record, the lack of parallel staging, the single staging event (compared with two SRB separations), the lack of SRBs, and the greater experience base that comes with the continuing use of the same hardware for military and commercial launches.  On the other hand, the Jupiter 120 gets some check marks because of the "all engines running" launch and the good record of the SRBs following the Challenger corrections.

However, under the "must use Shuttle-derived" mantra, I think the Jupiter 120 has more going for it from a safety standpoint than the Ares I.
Title: Re: DIRECT v2.0
Post by: Jorge on 05/23/2007 01:22 AM
Quote
imcub - 22/5/2007  6:23 PM

Quote
Kaputnik - 22/5/2007  1:21 PM

I mentioned this earlier but I don't think it was addressed.
In terms of presentation, I think you might be making a mistake in boldly asserting the superior safety of DIRECT over Ares-1. Remember, NASA already evaluated these two concepts and came to a different conclusion. You could instead say that NASA's analysis is slipping out of date/relevance as designs progress; that the ESAS safety numbers for a DIRECT-type vehicle were still masssively better than historic LOM/LOC figures; and also you could more subtly list those reasons that make DIRECT (in your eyes) safer than Ares (i.e. that the hardweare has flight history, amnogst other issues).
The current layout just seems a bit... arrogant.

I went back and re-read the proposal and I have to agree with Kaputnik about references to safety.  If I remember things correctly (and I'm sure someone will correct me if I am not), isn't NASA is quoting ARES/Orion as a LOC at 2000:1?  On the face of things, that's better than the 1400:1 being listed on direct.  

Yes, I know ... ARES is no longer using 4 segment SRB or the SSME and that it is going to be all new components except the SRB casings and that really invalidates the 2000:1 numbers being quoted.  I know that, but I visit this site everyday.  The intended audience, the people with the power and influence that might be able to alter NASA's chosen path, probably do not know this.  If NASA says ARES is shuttle derived and the LOC is 2000:1 ... then that's what your typical non-space geek audience will believe.    So ... a little more depth about why the Direct LOC numbers are better than ARES might be in order ... just a suggestion.

Slightly off the track ... has NASA changed the LOC/LOM numbers since they changed to a 5 segment SRB and J-2?  I don't recall seeing anyting different.

The 5-segment RSRB/J-2S option was in the original ESAS trade study (LV16). ESAS lists LOC as 1918:1.
-----
JRF
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/23/2007 01:49 AM
Quote
Jorge - 22/5/2007  7:22 PM
The 5-segment RSRB/J-2S option was in the original ESAS trade study (LV16). ESAS lists LOC as 1918:1.
-----
JRF

It cracks me up that they put four significant digits on these numbers.
Title: Re: DIRECT v2.0
Post by: jongoff on 05/23/2007 02:39 AM
Quote
Lee Jay - 22/5/2007  6:49 PM

Quote
Jorge - 22/5/2007  7:22 PM
The 5-segment RSRB/J-2S option was in the original ESAS trade study (LV16). ESAS lists LOC as 1918:1.
-----
JRF

It cracks me up that they put four significant digits on these numbers.

You too?
Title: RE: DIRECT v2.0
Post by: kraisee on 05/23/2007 03:44 AM
Quote
PMN1 - 22/5/2007  12:55 PM

Does China have the ability to build a vehicle in the 'Direct' class?

China has the ability to do anything it wants.   It isn't bogged down with workforce retention issues, inter-political party-squabbling and a contractor network already in place which needs to be reused.

Also, they have reasonable ties to the Russians, and could very easily side-step the development process for engines, instead opting to buy items which are already available off the shelf.

It isn't hard to imagine the Chinese buying RD-171 and RD-0120's, building three new stages and flying a Saturn-V class vehicle some time within the next decade.   They already have a few RD-170's which they have been reverse engineering for quite a while now, so I wouldn't be surprised if they don't field their own version independently at some point.

They only have to develop the technology to scale up their current tanks, and perfect the avionics and that gets them true heavy lift.   The engines, which are the most costly part of the whole venture, are available tomorrow for the right price.

Right now though, they are working on an evolution of the Long March - the 5 series, which will be firmly an EELV-class vehicle.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/23/2007 04:23 AM
Quote
SolarPowered - 22/5/2007  9:15 PM

Of course, if the cost of launching a payload is substantially reduced, then it might make economic sense to not spend billions of dollars designing out the last microgram of mass.  It might make sense to design inexpensive payloads that fly on inexpensive rockets, with the understanding that there is a 1% or a 4% or whatever chance that the payload will be lost.  It's a reasonable engineering tradeoff.

Correct.   While this is somewhat off-topic, I would like to say that the EELV fleet was designed primarily to launch military communications platforms and spy birds.   The commercial sector was supposed to share some of the costs by flying a bunch of its own satellites, but they never stepped up to the plate as expected.

It's interesting, that rocket technology is largely a well-understood engineering issue these days and is a familiar tool for many countries around the world.   But the satellites typically being flown on them are virtually at the pinnacle of each countries engineering capabilities.   They are likely to have some of the most advanced hardware any nation is likely to be able to develop on board.   This means they cost a lot, and are incredibly valuable to that nation.

With the commercial sector being pretty slow these days, that means that the bulk of modern satellite launches are going to be in this "expensive" & "national asset" class.   With that much at stake, even a 1% failure rate would prove to be pretty costly, and that cost pushes the majority of payloads flown these days into a much closer safety category to that of manned flight safety.

I actually agree that Atlas-V is probably noticeably safer than Shuttle, and some variants of Atlas may be safer than Jupiter-120.   But those options completely ignore the political purse-string holders who have demanded that NASA retain the Shuttle Workforce during this transition.   Ignoring that is a road to nowhere, because without political support, NASA's budget dries up even more than it is doing today, and we end up with nothing at all.

And I don't even want to open up the can of worms involving using Russian engines to power America's new flagship missions...   That's a political "never in a million years" non-starter if ever I heard one.   Sorry, but it is.

The DIRECT team would probably agree that there are other alternatives which do better in some areas, such as "safety".   But we recognise the simple fact that "safety" is not the be-all and end-all of the decision making process.   Budget isn't the whole story.   Schedule isn't.   Technological development isn't.   Infrastructure isn't.   What is really needed is a solution which addresses all these factors (and others) and which does so in a way to satisfy all these different requirements.

DIRECT's architecture, while not a "perfect" solution in any specific field, does specifically address all the different forces pulling at NASA and attempts to create the "best fit" to accomplish all the goals to everyone's satisfaction, while improving on the existing solution.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/23/2007 04:30 AM
Quote
jongoff - 22/5/2007  10:39 PM

Quote
Lee Jay - 22/5/2007  6:49 PM

Quote
Jorge - 22/5/2007  7:22 PM
The 5-segment RSRB/J-2S option was in the original ESAS trade study (LV16). ESAS lists LOC as 1918:1.
-----
JRF

It cracks me up that they put four significant digits on these numbers.

You too?

I'm not convinced they are *that* unreasonable.

I don't believe that the vehicles themselves are an order of magnitude better than the "typical" 1:100 failure rates we've gotten used to, I believe that the escape system on top can probably account for 10 times the safety of something without (such as STS).

Shuttle had 82 flights (IIRC) between one loss and the next, so it has an LOM of 1:82 and an LOC of 1:82.

The Atlas family has had just over 74 flights since its last loss, so it has an LOM of 1:74 ish.

The Delta's have had quite a few more failures throughout their histories, as have the Titan's, so I'll leave them out for now.

The Russian R7 family of launchers (including Soyuz/Progress) has an incredible history with over 1,700 flights to its name, and has a better than 1:100 LOM rate today and a (so far) perfect LOC rate thanks to its Launch Escape System proving to have saved at least one crew (Soyuz T-10) already during launch operations.   All other Cosmonauts deaths have been outside of the ascent phase of the flight, so their loss can not be attributed to the launch vehicle safety ratings.

So lets say that 1:100 is achievable for a modern rocket.

But it is the inclusion of an LAS on any launch vehicle which offers orders of magnitude improvements in the realm of safety for crews.   An LAS ought to save at least 9 crews out of 10 in ten abort scenarios.

With a 1:100 LV, using an LAS reducing crew loss to 1 in 10 per abort - you could realistically achieve a 1 in 1000 LOC.

It's hypothetically possible.   Although I would expect in the real world, you could probably halve all the numbers and be a lot closer to the truth.

I for one don't believe the 1:2000 claims though.   I think that's pure hyperbole.   An all-new 1st stage, an all-new upper stage, a virtually all-new U/S main engine, in a configuration which has never even been practiced before, offering double the safety of anything else?   Not a chance.   Only the completely uninformed could be convinced by that.

Ross.
Title: Re: DIRECT v2.0
Post by: CFE on 05/23/2007 04:54 AM
I think that it's somewhat of a crapshoot to try and quantify either the schedule or the budget for a major launch vehicle program such as Ares or Jupiter.  I even question whether it's fair to compare two vehicle designs on the basis of statistical failure rates or projected budgets.

In the field of space acquisition, budgets invariably balloon.  Many times this is because we're breaking new ground (technically and operationally) and can't really predict how much it will cost.  Other times, the program's supporters will use a lie in order to get the initial funding from congress.  After all, the sticker-shock from an accurate budget estimate would be enough to kill most space acquisition programs before they got off the drawing board.

At the same time, very few launch vehicles have flown enough times to validate loss-of-vehicle numbers.  Atlas II/III had a spotless record, but that group of vehicles only had 69 total launches.  On the other hand, the shuttle originally had loss-of-crew numbers that were better than 1-in-1000.  Statistically, it's 2-in-117.  To some extent, the original shuttle reliability numbers can't be faulted for ignoring human error.  The people who came up with the original reliability estimates didn't think that mission managers would be dumb enough to launch when the SRB's were below their minimum operating temperature.  They also failed to see (as did many in NASA, all the way until the cause of the Columbia disaster was established) that ET insulation had a fairly high probability of causing fatal TPS damage.

It's the extreme uncertainties of cost and safety estimates that make me favor the intuitive comparison that Jon Goff and others have taken in comparing Ares I to Jupiter 120.  Development of the 5-segment SRB, all-new launch facilities, an all-new upper stage, and a mostly-new cryogenic engine (all flying in a new configuration) should logically be more expensive than stock SRB's, a minimally-modified ET, off-the-shelf main engines, and moderately-modified facilities, all flying in a similar configuration to the shuttle.  As far as safety goes, we know that Jupiter 120 will be inherently safer than shuttle; due to the relocation of the TPS relative to ET foam, the use of post-Challenger SRB's, simplified main engines not running at >100% thrust, and smarter mission managers who are committed to safety, Jupiter 120 should avoid all of the problems that we've seen on the shuttle thus far.  The new configuration will certainly create new failure modes that will have to be caught, analyzed, and mitigated; the same is true for Ares I & Ares V.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/23/2007 04:59 AM
Well said CFE.
Title: Re: DIRECT v2.0
Post by: jongoff on 05/23/2007 04:59 AM
kraisee,
Quote
I for one don't believe the 1:2000 claims though.   I think that's pure hyperbole.

Exactly.  If I remember what I was reading correctly, they actually assumed that the actual Ares-I would only have a failure resulting in LOM about 1 in 400 flights (with enough of the potential failures being so catastrophic that the LAS is assumed to work only 20% of the time).  The vehicle is almost 100% clean-sheet design, but they're expecting it to be almost 4-5x more reliable than any other vehicle that's ever flown.  That smacks of hubris.  

Quoting the reliability numbers for this vehicle out to 4 significant figures--now that's just plain comedy.

~Jon
Title: Re: DIRECT v2.0
Post by: Thorny on 05/23/2007 05:37 AM
Quote
SolarPowered - 22/5/2007  8:15 PM
Existing launch systems tend to have a pretty poor reliability record, compared to what is acceptable for human risk.  For example, we've lost 2 Shuttles in just over 100 flights.  The record of the Delta family shows many failures over the years.  (The Atlas family has actually done a bit better, with >100 flights now with no failures.


No, the Atlas family is currently at 82 consecutive successes dating back to Atlas-Centaur 104 in 1993.

There were 63 Atlas IIs launched, none lost, however three Atlas Is were lost in the early '90s, including 2 consecutive failures (in 1992 and 1993) after Atlas II debuted. There were six Atlas IIIs, all successful. All nine Atlas Vs to date have been successful.

There have been 166 launches of Atlas-Centaur family rockets, although the new Atlas V has very little in common with the classic balloon-tank Atlas which was retired in 2005. (That doesn't stop LockMart bragging about "82 consecutive successes" though. What's next? The F-35 already has a fantastic combat record because its named Lightning II?  :laugh:



Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/23/2007 07:00 AM
Quote
Thorny - 22/5/2007  10:37 PM

Quote
SolarPowered - 22/5/2007  8:15 PM
Existing launch systems tend to have a pretty poor reliability record, compared to what is acceptable for human risk.  For example, we've lost 2 Shuttles in just over 100 flights.  The record of the Delta family shows many failures over the years.  (The Atlas family has actually done a bit better, with >100 flights now with no failures.


No, the Atlas family is currently at 82 consecutive successes dating back to Atlas-Centaur 104 in 1993.

There were 63 Atlas IIs launched, none lost, however three Atlas Is were lost in the early '90s, including 2 consecutive failures (in 1992 and 1993) after Atlas II debuted. There were six Atlas IIIs, all successful. All nine Atlas Vs to date have been successful.

There have been 166 launches of Atlas-Centaur family rockets, although the new Atlas V has very little in common with the classic balloon-tank Atlas which was retired in 2005. (That doesn't stop LockMart bragging about "82 consecutive successes" though. What's next? The F-35 already has a fantastic combat record because its named Lightning II?  :laugh:


OK, I stand corrected.  :)  I could have sworn that I read 100+, but I guess I'm getting old.  (I do actually remember the first landing on the moon. :laugh: )

I'll also agree that keeping count through multiple redesigns doesn't necessarily mean much about what they're building now.  On the other hand, I would imagine that many of the same people are involved, so there should be experience that carries over from one design to the next.

To restate, I think it's fair to say that LockMart has shown that they are capable of designing and building reliable rockets.  But, the Altas V hasn't been around long enough to really claim that it has a track record yet.
Title: Re: DIRECT v2.0
Post by: renclod on 05/23/2007 08:18 AM
clongton
Quote
- 11/5/2007  5:01 PM

After examining the move and shock envelope around each engine, allowing for the full range of gimbal motion, plus margin, and addressing the design of an appropriate thrust structure, the distance between the two outboard engines, center to center, is approximately the same as NASA currently baselines for the Ares-V outboard engines.
kraisee
Quote
- 11/5/2007  4:50 PM
Just to clarify, the engines are mounted in-line to keep maximum distance between them and the SRB's.

Just a benign comment...

I don't know what are the Ares V designers going to do about squeezing five RS-68 plumes between two 5-seg SRM plumes, but the Jupiter-120/232 designers will have to squeeze three RS-68 plumes between two 4-seg SRM plumes - by 2012.

This is new and a promise for spectacular. There never was, I'd say, a clear description of the interaction between such parallel plumes, featuring different exhaust speeds and close proximity. The "Shuttle-derived" aleviation does not apply !

Just open a picture of the Delta IV Heavy launch in an imaging software, stretch the 10 m between the "outboard engines" to the 8 m corresponding to Jupiter-232 and then copy/paste to a suitable picture of any Shuttle launch - now you see what I mean.

And another benign comment... related to this funny document:

http://www.boeing.com/defense-space/space/constellation/references/presentations/Space_Shuttle_Integration_Lessons_Learned.pdf

and speciffically to the "SRB Ignition Overpressure (IOP) Suppression Configuration"

The water spray needs to be adapted for Jupiter-120/232 (and Ares-V) since you have the three engines fireing between the SRB's. Also the IOP will manifest differently since the three RS-68 plumes will be right there. Different flame deflectors and ample modifications to the MLP IMHO.

One last comment... corrosive, I admit:

The strongest point of the Direct-2 proposal is also the weakest one. I mean, the two 120/232 look like they've been through the Procrustes' Bed. Twice.  First, because they retain the LH2 tank from the Shuttle (be it minimal "less milling" and all). Second, because they share the common "Jupiter Common Core" but have different missions - especially if you listen to Jim saying that the 120 will boost only the C E V. The case for a payload under the CEV is not clear.

Other than that I join many other forum members in congratulating your team and I express my admiration (and envy !) for your work. I understand that your effort is based on seeing an "clear and present danger" to the Ares-V promise.

Title: Re: DIRECT v2.0
Post by: CFE on 05/23/2007 08:30 AM
Plume impingement between the RS-68's and SRB's shouldn't be a problem on Jupiter.  The spacing between SRB's and RS-68's is greater than on Delta IV Heavy due to the wider core, and because the RS-68s are in a line that's perpendicular to the line between the SRB's (as opposed to being co-linear.)  In Delta IV Heavy, spacing between engines (measured center-to-center) is ~5 meters.  On Jupiter, it's ~6 meters at the narrowest point (center engine on Jupiter 232 to SRB center.)

Additionally, impingement between RS-68's will not be an issue on Jupiter 120, due to the blank spot in the center of the core where the third RS-68 will be on Jupiter 232.  While impingement between RS-68's might be an issue on Jupiter 232, I don't suspect it's a showstopper by any stretch of the imagination.
Title: Re: DIRECT v2.0
Post by: JIS on 05/23/2007 08:37 AM
Quote
jongoff - 22/5/2007  6:23 PM

Smetch,
Quote
NASA won’t be able to ignore the CBO and OMB this time around.

Now CBO and OMB may be just the right audience to send this information to.   Next time they do an analysis, if they also compare DIRECT to the Ares I/V and it comes out anywhere near as good as I think it would, that would help your cause a lot.

~Jon

CBO analysis would really help to gain some credibility. I think that the last CBO didn't fully incorporated NASA changes to the ESAS study. It could be really interresting to see updated estimations.
Title: Re: DIRECT v2.0
Post by: Jim on 05/23/2007 11:36 AM
Quote
SolarPowered - 22/5/2007  9:15 PM

Existing launch systems tend to have a pretty poor reliability record, compared to what is acceptable for human risk.  For example, we've lost 2 Shuttles in just over 100 flights.  The record of the Delta family shows many failures over the years.  (The Atlas family has actually done a bit better, with >100 flights now with no failures.)
.

Many failures?  Delta family is just as good as Atlas.
Title: Re: DIRECT v2.0
Post by: Drapper23 on 05/23/2007 12:56 PM
http://www.space.com/spacenews/spacenews_briefs.html  The 2008 Congressional Budget Resolution supports the VSE & the full Bush funding request for NASA. The budget resolution also supports NASA's goal of reducing the gap between retiring the space shuttle and fielding its successor.  This last statement is an opening that the Direct 2 supporters should size upon in. It provides the perfect rationale as to why a major effort should be made to contact Congressional offices about the advantages of Direct 2.
Title: Re: DIRECT v2.0
Post by: renclod on 05/23/2007 02:16 PM
CFE
Quote
- 23/5/2007  11:30 AM
I don't suspect it's a showstopper by any stretch of the imagination.

It was just a benign comment, that is a minor observation - what showstopper ?!

Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/23/2007 02:22 PM
The biggest advantage to direct, IMHO is the cutting of years off of the development schedules.    Yes there are impressive cost savings,  but NASA’s annual budget  is going to remain fixed (at least in theory).  So the savings won’t occur until direct is flying.
Congress tends to be very short sighted in the budget department.  They mostly concern themselves with the spending over the next 4 years.   Since the cost savings won’t occur until 5 years down the road,  that might not be the biggest selling point.

 As far as the proposed schedule,  from 2009 to 2012 there is only one flight per year.
Why so few?  Is the limiting factor the completion of the CEV’s?    After the first flight there will be a lot of analysis,  design changes, etc.    But after the second launch it seems like the schedule could be more aggressive.

  At the end of the proposal is says that the plan is going to be presented in September  in Long Beach.   Is this at a conference?   And what is the purpose in stating this in the proposal
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/23/2007 02:44 PM
Quote
veedriver22 - 23/5/2007  7:22 AM

The biggest advantage to direct, IMHO is the cutting of years off of the development schedules.    Yes there are impressive cost savings,  but NASA’s annual budget  is going to remain fixed (at least in theory).  So the savings won’t occur until direct is flying.
Congress tends to be very short sighted in the budget department.  They mostly concern themselves with the spending over the next 4 years.   Since the cost savings won’t occur until 5 years down the road,  that might not be the biggest selling point.

 As far as the proposed schedule,  from 2009 to 2012 there is only one flight per year.
Why so few?  Is the limiting factor the completion of the CEV’s?    After the first flight there will be a lot of analysis,  design changes, etc.    But after the second launch it seems like the schedule could be more aggressive.

  At the end of the proposal is says that the plan is going to be presented in September  in Long Beach.   Is this at a conference?   And what is the purpose in stating this in the proposal

Yes AIAA Space 2007,  even Mike and/or Scott is supposed to be there.  Wouldn't it be great if they went to the presentation.  

Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/23/2007 03:07 PM
Quote
SMetch - 23/5/2007  8:44 AM
Yes AIAA Space 2007,  even Mike and/or Scott is supposed to be there.  Wouldn't it be great if they went to the presentation.  

It has been my experience that engineers will attend virtually any meeting to which they are invited if they are offered free pastries.

Just a thought.

Lee Jay
Title: Re: DIRECT v2.0
Post by: TrueBlueWitt on 05/23/2007 04:51 PM
Just saw that JWST is getting an Orion Docking ring.. what's the point if you're flying Orion on Ares 1???  There's NO way in the world it can get there can it?  I can't imagine them launching an Ares 5 in addition just to get an Orion out there.  plus would be available so far after JWST launch it wouldn't be much use.

What about Jupiter.. would the base configuration be capable of getting Orion to JWST?
Title: Re: DIRECT v2.0
Post by: clongton on 05/23/2007 05:02 PM
Quote
TrueBlueWitt - 23/5/2007  12:51 PM

Just saw that JWST is getting an Orion Docking ring
Your source?
Title: Re: DIRECT v2.0
Post by: tmckinley on 05/23/2007 05:03 PM
Ares V will be manrated, plus there's the chance of Ares IV. I believe that's how they plan on getting to NEO's if they ever have the money. An Ares I and V wouldn't both be launched.
Title: Re: DIRECT v2.0
Post by: Jorge on 05/23/2007 05:09 PM
Quote
clongton - 23/5/2007  12:02 PM

Quote
TrueBlueWitt - 23/5/2007  12:51 PM

Just saw that JWST is getting an Orion Docking ring
Your source?
http://www.space.com/businesstechnology/070523_techwed_jwst_dock.html
-----
JRF
Title: Re: DIRECT v2.0
Post by: kraisee on 05/23/2007 05:18 PM
Quote
TrueBlueWitt - 23/5/2007  12:51 PM

Just saw that JWST is getting an Orion Docking ring.. what's the point if you're flying Orion on Ares 1???  There's NO way in the world it can get there can it?  I can't imagine them launching an Ares 5 in addition just to get an Orion out there.  plus would be available so far after JWST launch it wouldn't be much use.

What about Jupiter.. would the base configuration be capable of getting Orion to JWST?

A Jupiter 232 has more than sufficient performance to launch a 22mT CEV to James Webb, along with a substantial mission module mass.

With the performance of the J-120, we know it can place a CEV into High Earth Orbit already, and may even be able to deliver a CEV to Geostationary assuming it does not need all of its TLI propellant.

Ares-I is incapable of supporting any of these missions.

Ross.
Title: Re: DIRECT v2.0
Post by: imcub on 05/23/2007 05:40 PM
Quote
CFE - 22/5/2007  9:54 PM
...   As far as safety goes, we know that Jupiter 120 will be inherently safer than shuttle ... simplified main engines not running at >100% thrust ...

Personally, I don't have a problem with engines running above their rated thrust levels ... Scotty did it dozens of times ...
Title: Re: DIRECT v2.0
Post by: TrueBlueWitt on 05/23/2007 05:41 PM
Quote
tmckinley - 23/5/2007  1:03 PM

Ares V will be manrated, plus there's the chance of Ares IV. I believe that's how they plan on getting to NEO's if they ever have the money. An Ares I and V wouldn't both be launched.

But will either of those configurations really be flying in time to get Orion to JWST to assist with start-up issues (panel deployment and the like)?  That is the stated purpose for adding the docking ring to JWST since the rest of telescope is not servicable.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/23/2007 05:48 PM
JWST is on its own until a Heavy Lifter is operational.

The Ares-V won't be available until 2019 at the earliest, and Ares-IV appears to require almost all of it's systems, so I just don't see it being available any sooner.   Perhaps 1 year sooner if they're lucky - but that assumes considerable development funds being redirected away from the Lunar missions and towards this.   I think that's very unlikely.

A Jupiter-232 could service JWST from around 2015 on.

A Jupiter-120 with a man-rated Centaur stage instead of the EDS could probably do it earlier if there were an actual requirement.

Ross.
Title: Re: DIRECT v2.0
Post by: Alpha Control on 05/23/2007 06:09 PM
And the ship never did fly apart, despite the constant protestations of "she canna hold together"!

To keep this on topic, as a long-time space enthusiast (IT professional but non-engineer), I have been impressed with the work done on Direct 2.0.  I take the team at their word on their statements, and look forward to reading more responses from the various communities as the process moves ahead.

David
Title: Re: DIRECT v2.0
Post by: Thorny on 05/23/2007 06:15 PM
Quote
kraisee - 23/5/2007  12:48 PM

The Ares-V won't be available until 2019 at the earliest, and Ares-IV appears to require almost all of it's systems, so I just don't see it being available any sooner.   Perhaps 1 year sooner if they're lucky - but that assumes considerable development funds being redirected away from the Lunar missions and towards this.   I think that's very unlikely.

Ross.

It might be possible to get Orion to JWST with two Ares I launches... one with the Orion, the other with no payload, just a docking adapter on the US. The two dock and relight the US engine.
Title: Re: DIRECT v2.0
Post by: Thorny on 05/23/2007 06:19 PM
Quote
CFE - 23/5/2007  3:30 AM

Plume impingement between the RS-68's and SRB's shouldn't be a problem on Jupiter.

Looks to me like it would be a challenge for the MLP, though. There sure isn't much space between the two SRB mounts on the existing MLP for a core flame duct. Or will Jupiter's RS-68s be air-lit?
Title: Re: DIRECT v2.0
Post by: Will on 05/23/2007 06:23 PM
I'm afraid you're overpromising again, just as you did with v1.0. In the baseline Direct v2.0 lunar mission, one of your launches simply replaces the Ares I in launching the CEV, so your other launch has to do the same work as the Ares V. You seem to be using fundamentaly more optimistic assumptions in your calculations than the NASA baseline, both assuming that a smaller LSAM is just as good, and that you can get almost as much mass into LEO with a much smaller launcher for the EDS/LSAM.

There are ways to fix the problem, but they have costs and you haven't faced them.

Will
Title: Re: DIRECT v2.0
Post by: clongton on 05/23/2007 06:23 PM
Quote
Thorny - 23/5/2007  2:19 PM

Quote
CFE - 23/5/2007  3:30 AM

Plume impingement between the RS-68's and SRB's shouldn't be a problem on Jupiter.

Looks to me like it would be a challenge for the MLP, though. There sure isn't much space between the two SRB mounts on the existing MLP for a core flame duct. Or will Jupiter's RS-68s be air-lit?
This was covered in detail on the v1 paper with some good graphical examples.
Grab a copy and check it out.
Title: Re: DIRECT v2.0
Post by: clongton on 05/23/2007 06:30 PM
Quote
Will - 23/5/2007  2:23 PM

I'm afraid you're overpromising again, just as you did with v1.0. In the baseline Direct v2.0 lunar mission, one of your launches simply replaces the Ares I in launching the CEV, so your other launch has to do the same work as the Ares V. You seem to be using fundamentaly more optimistic assumptions in your calculations than the NASA baseline, both assuming that a smaller LSAM is just as good, and that you can get almost as much mass into LEO with a much smaller launcher for the EDS/LSAM.
There are ways to fix the problem, but they have costs and you haven't faced them.
Will
Blanket criticisms don't help. Please be specific so that we may address your concerns.
What assumptions? As opposed to exactly which NASA assumptions?
Overpromising in what specific way?
What ways to fix what problems, and what specific costs have we not faced?
If you will provide those specifics, we will address them for you.
Title: Re: DIRECT v2.0
Post by: ACEMANN on 05/23/2007 06:43 PM
Hello all, long time lurker, first post.

I had to point this out. I just read the article about adding the Orion docking ring as well and was (sadly) amused at Griffin's response. Quoting the Space.com article:

"The decision to add a docking ring to the Webb telescope was news to Griffin. Asked about it May 16, he said: "A year or two ago I asked people if it wouldn't be smart to at least have some capability to dock Orion with James Webb such that if people wanted to service it, they could do so. It only seems to me to make sense to not preclude that. I didn't tell them to do it. So if they are doing it, they must have studied it and come to the conclusion that it is a worthwhile thing to do." "

IMO, seems like an "oh crap" moment when taking into account the limited capability that will exist when the JWST is deployed, approx. 2013. Interesting article.
Title: Re: DIRECT v2.0
Post by: Will on 05/23/2007 07:23 PM
Your Jupiter 232 is similar to ESAS Launcher 29, except that launcher 29 has two more engines on the J-2 stage. 29 is estimated to have useful payload of 92 mT to 28.5 leo, 232 estimated useful payload of 108 mT.

232 is estimated to throw 50 mT useful payload to TLI, only 5 tonnes less than Ares V.

You estimate 38 mT LSAM is suitable for your baseline mission. ESAS assumed 45 mT .

Please explain why your useful payload assumptions seem to be more optimistic, and why you think a smaller LSAM is sufficient.

Will McLean
willscommonplacebook.blogspot.com

Title: Re: DIRECT v2.0
Post by: Jim on 05/23/2007 07:28 PM
Quote
Thorny - 23/5/2007  2:15 PM

Quote
kraisee - 23/5/2007  12:48 PM

The Ares-V won't be available until 2019 at the earliest, and Ares-IV appears to require almost all of it's systems, so I just don't see it being available any sooner.   Perhaps 1 year sooner if they're lucky - but that assumes considerable development funds being redirected away from the Lunar missions and towards this.   I think that's very unlikely.

Ross.

It might be possible to get Orion to JWST with two Ares I launches... one with the Orion, the other with no payload, just a docking adapter on the US. The two dock and relight the US engine.

The Ares I upperstage is a launch stage.  It doesn't have the capability to restart
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/23/2007 08:25 PM
Will the CEV be capable of doing an LOI burn?   If not a rescue mission with just a CEV would not be possible.
Title: Re: DIRECT v2.0
Post by: Jim on 05/23/2007 08:28 PM
Quote
veedriver22 - 23/5/2007  4:25 PM

Will the CEV be capable of doing an LOI burn?   If not a rescue mission with just a CEV would not be possible.

nope, just TEI
Title: Re: DIRECT v2.0
Post by: kraisee on 05/23/2007 08:48 PM
Will,
Thanks for finding that.   I had actually forgotten about LV-29 in ESAS (its in Section 6, Page 421 for everyone to see BTW).   I don't know who in ESAS came up with the LV-29 spec, but it is, frankly, quite ridiculous.

There is no reason at all to have four J-2S+'s.   The fact is, that a single engine is only *just* slightly underpowered for this configuration.   Two engines offer quite a surplus of necessary thrust.   Four is obscene overkill for this particular vehicle - not to mention that having that many engines causes higher safety concerns and greater recurring expenses too.

It is little wonder that LV-29 couldn't be made to perform all that well.   It has four large U/S engines, so the U/S instantly weighs a lot more than a 2-engine configuration (13 tons of engines alone, not including the additional structural mass needed to mount them).   Also, to create the necessary acceleration during the U/S phase of the ascent, it needs a LOT more propellant to fuel four powerplants all the way to orbit.   This again increases the mass of the tanking.

This much heavier EDS must then be lifted initially by the same SRB's and core stage.   The effective performance of the boosters and core stage phases of the flight is thus reduced noticably.   This leaves the U/S with even more work to do to achieve orbit.

Worse still, with four J-2X's, some will have to shut down half of the U/S engines later in the ascent to avoid breaking through 4g acceleration limit as the propellant drains and the thrust:weight ratio increases.   This then means that LV-29 ends up carrying at least 13 tons of dead engine weight to orbit every flight.   This is ultimately just an awful solution.

A 2-engined U/S is far more efficient at achieving the requirements.   It has *plenty* enough thrust, and doesn't require half of the U/S ascent propellant.

Given that LV-29 was briefly included, I have to wonder why a 2-engined variant wasn't assessed and included in the published ESAS Report.

As an aside, I also wondered why ESAS put that gargantuan payload shroud on top of LV-29?   It makes no sense to me.   Does *anyone* know why they did that?


Regarding the LSAM, we aren't actually proposing a smaller LSAM at all.   We are planning that a 2-launch J-120/J-232 mission will still be able to launch a 45mT (GLOW) LSAM - matching performance of the Ares-I and Ares-V for all regular missions.

However, the very first test flights *could* be flown without the need of propellant transfer.   *If* that is not utilized, that would result in regular LSAM, short-fuelled, massing 38mT (GLOW) for just those test flights.   This is an option which can be done to simplify the first few test flights while we "find our feet" in this new program.   Once we've gotten a few flights under the belt, and have confidence, the propellant transfer can be implemented and we instantly match Ares-I/V performance.

The propellant transfer then enables larger-that-Ares missions as soon as NASA wishes.   By flying the CLV flight on a J-232, and by rendezvousing close to the moon instead of Earth, the propellant transfer capability enables NASA to expand to a 78mT LSAM.

This three-step scalable program is unavailable to Ares-I/V combo where a 45mT LSAM is the only alternative, and because NASA has bought two new launch vehicles, there is not going to be cash available to do anything else anyway.

Ross.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/23/2007 09:06 PM
The CEV not being able to perform a LOI could be a big deal.   If  anything happens to the CEV while the crew are on the surface or in the docking procedure the crew would be stranded.    For a rescue you would have to have two launches,  a CEV and another LSAM.    Getting both done & linked up would take some time.  

  There are going to be events that can lead to LOC.   You can’t eliminate all risks.  But in any situation that results in the crew being stranded & lost, that will cause a huge public outcry.   Take for instance Columbia.   When the public found out that the Columbia could not make its way to the ISS (even if the wing damage were apparent),  and therefore its only option was to reenter,  people went nuts.    And now they won’t fly the shuttle on missions away from the ISS.

 This could be a benefit for direct.   With its capacity I think you could give the CEV the capability to do an LOI burn giving you more options for rescue.          
Title: Re: DIRECT v2.0
Post by: Thorny on 05/24/2007 01:40 AM
Quote
Jim - 23/5/2007  2:28 PM

The Ares I upperstage is a launch stage.  It doesn't have the capability to restart

The changes between S-IVBs for Saturn IB and Saturn V weren't hugely complex, mostly just the big OAMS and extra batteries and helium bottles. The J-2X engine will already be capable of restart and Ares I-US already will have that honkin' big roll control system. And if Ares IV starts to look like a reality, those changes would have to be made anyway.

Title: Re: DIRECT v2.0
Post by: JIS on 05/24/2007 09:25 AM
Quote
veedriver22 - 23/5/2007  9:25 PM

Will the CEV be capable of doing an LOI burn?   If not a rescue mission with just a CEV would not be possible.
Actually going from highly eliptical orbit to L2 sun-earth orbit is not demanding. The problem is a long loitering. Servicing of Web telescope is not a good idea as it is too far and it's not even serviceable. Some quick fix (refueling or helping with stacked sunshield or PV panel) could be possible with robotic mission.
Title: Re: DIRECT v2.0
Post by: JIS on 05/24/2007 11:11 AM
Quote
kraisee - 23/5/2007  9:48 PM

Will,
Thanks for finding that.   I had actually forgotten about LV-29 in ESAS (its in Section 6, Page 421 for everyone to see BTW).   I don't know who in ESAS came up with the LV-29 spec, but it is, frankly, quite ridiculous.

There is no reason at all to have four J-2S+'s.  

They are very similar vehicles. Same SRBs, same core, same engines, same payload to LEO, similar US GLOW (381mT for Jupiter US, 350 mT for LV-29). The only difference is the t/w ratio. 1.09 for LV-29 US, 0.51 for Jupiter EDS. The T/W ratio doesn't need to be a problem if the core itself provides sufficient dV. (Ares V with extremelly big core has EDS with 0.44 T/W)
Wery suspicious difference is also in the vehicle GLOW which is 2450mT for LV-29 and 2372mT for Jupiter-232.
This means that LV-29 core+SRBs weights about 110mT more than the Jupiter Core+SRBs. As the SRBs are the same the difference is apparently in the core itself. This is consistent with my comments here earlier. I knew that DIRECT is uderestimating structural weight but I didn't expect such a big difference. For example the SDV proposal done by ATK (ET-size core with 4 x RS-68) has the core weighting 31mT more than Jupiter core. It is difficult to make proper analysis with limited info only.
Of course if the dV from the core is higher it is possible to have lower thrust (less engines) on US. With extremelly low US dry mass you get Jupiter.
Title: Re: DIRECT v2.0
Post by: JIS on 05/24/2007 11:24 AM
Quote
veedriver22 - 23/5/2007  10:06 PM

The CEV not being able to perform a LOI could be a big deal.   If  anything happens to the CEV while the crew are on the surface or in the docking procedure the crew would be stranded.    For a rescue you would have to have two launches,  a CEV and another LSAM.    Getting both done & linked up would take some time.  

  There are going to be events that can lead to LOC.   You can’t eliminate all risks.  But in any situation that results in the crew being stranded & lost, that will cause a huge public outcry.   Take for instance Columbia.   When the public found out that the Columbia could not make its way to the ISS (even if the wing damage were apparent),  and therefore its only option was to reenter,  people went nuts.    And now they won’t fly the shuttle on missions away from the ISS.

 This could be a benefit for direct.   With its capacity I think you could give the CEV the capability to do an LOI burn giving you more options for rescue.          

That's unrealistic. If the crew is stranded at the lunar base they have to wait for the next crew mission or extra supplies by Ares V/cargo LSAM. If they are stranded at LLO they die anyway. Orion & ascend stage of LM can't support them long enough. There is nothing you can do unless you have a spare manned mission prepared stright away.
Title: Re: DIRECT v2.0
Post by: JIS on 05/24/2007 12:09 PM
Quote
kraisee - 23/5/2007  9:48 PM

Will,
Thanks for finding that.   I had actually forgotten about LV-29 in ESAS (its in Section 6, Page 421 for everyone to see BTW).   I don't know who in ESAS came up with the LV-29 spec, but it is, frankly, quite ridiculous.

There is no reason at all to have four J-2S+'s.   The fact is, that a single engine is only *just* slightly underpowered for this configuration.   Two engines offer quite a surplus of necessary thrust.   Four is obscene overkill for this particular vehicle - not to mention that having that many engines causes higher safety concerns and greater recurring expenses too.

The burnout T/W ratio around 4 is nothing uncommon for US. It's actually required to get that payload to orbit.  

Quote
It is little wonder that LV-29 couldn't be made to perform all that well.   It has four large U/S engines, so the U/S instantly weighs a lot more than a 2-engine configuration (13 tons of engines alone, not including the additional structural mass needed to mount them).

One J-2X is max 2mT. One RS-68 is less than 7mT.

Quote
Also, to create the necessary acceleration during the U/S phase of the ascent, it needs a LOT more propellant to fuel four powerplants all the way to orbit.   This again increases the mass of the tanking.

It's not about propellants. It's about dV. Four engines have more acceleration and less gravity losses. Again 4g's acceleration is nothing uncommon for US.

Quote
This much heavier EDS must then be lifted initially by the same SRB's and core stage.   The effective performance of the boosters and core stage phases of the flight is thus reduced noticably.   This leaves the U/S with even more work to do to achieve orbit.

LV-29 second stage is actually lighter than Jupiter EDS.

Quote
Worse still, with four J-2X's, some will have to shut down half of the U/S engines later in the ascent to avoid breaking through 4g acceleration limit as the propellant drains and the thrust:weight ratio increases.   This then means that LV-29 ends up carrying at least 13 tons of dead engine weight to orbit every flight.   This is ultimately just an awful solution.

Wrong again. Extra J-2S+ weight less than 2mT each, the maximal accelartion of 4g is achieved at the burnout.

Quote
A 2-engined U/S is far more efficient at achieving the requirements.   It has *plenty* enough thrust, and doesn't require half of the U/S ascent propellant.

Less thrust US has high gravity losses and has to fly on more lofted trajectory. The only reason for EDS to have a low thurst is for TLI burns where a high thrust is not required.

Quote
Given that LV-29 was briefly included, I have to wonder why a 2-engined variant wasn't assessed and included in the published ESAS Report.

It wasn't apparently viable for 3xRS-68 core.

Quote
As an aside, I also wondered why ESAS put that gargantuan payload shroud on top of LV-29?   It makes no sense to me.   Does *anyone* know why they did that?

Ctr-C, Ctrl-V from LV-27?

It even looks as the RS-68 or SRBs are somewhat tweaked for LV-29 as it seems to have a higher liftoff thrust than expected for common RS-68 and SRBs

Title: Re: DIRECT v2.0
Post by: Jim on 05/24/2007 01:28 PM
Quote
Thorny - 23/5/2007  9:40 PM

Quote
Jim - 23/5/2007  2:28 PM

The Ares I upperstage is a launch stage.  It doesn't have the capability to restart

The changes between S-IVBs for Saturn IB and Saturn V weren't hugely complex, mostly just the big OAMS and extra batteries and helium bottles. The J-2X engine will already be capable of restart and Ares I-US already will have that honkin' big roll control system. And if Ares IV starts to look like a reality, those changes would have to be made anyway.


It isn't that easy.
S-IVB's were designed and scarred for it from the beginning.    the Ares upperstage isn't design for it.

No posigrade thrusters, no zero g vent system, no recirculation system, stage insulation not designed for onorbit, no onorbit cooling for avionics and many more


OAMS flew on the Gemini spacecraft

BTW First stage roll control is on the interstage.

Title: Re: DIRECT v2.0
Post by: Will on 05/24/2007 01:41 PM
Quote
kraisee - 23/5/2007  3:48 PM

Will,
Thanks for finding that.   I had actually forgotten about LV-29 in ESAS (its in Section 6, Page 421 for everyone to see BTW).   I don't know who in ESAS came up with the LV-29 spec, but it is, frankly, quite ridiculous.

There is no reason at all to have four J-2S+'s.   The fact is, that a single engine is only *just* slightly underpowered for this configuration.   Two engines offer quite a surplus of necessary thrust.   Four is obscene overkill for this particular vehicle - not to mention that having that many engines causes higher safety concerns and greater recurring expenses too.


Ross.

It sounds like you are assuming that the four J-2S stage is the upper/TLI Stage. I think it's clear from the ESAS report that like every other launcher except the  one finally selected, the TLI stage is in addition, and payload to LEO does not include a suborbital burn from the TLI stage. Thus the big shroud.

It's probably true that staging like 232 is superior for a lunar mission, if only on the basis of simplicity. That doesn't explain why 232 has superior LEO payload to LV-29: one would expect the reverse. A design that's optimized for TLI or GTO will be underpowered for lifting heavier payloads to LEO: that's why Atlas is designed to use two RL-10s on LEO missions rather than one.

Your report would be clearer if you specified whether payload estimates were net or gross, so comparisons could be made more easily with ESAS. Which is it?

Also, you need to be clearer that to reach operational capacity equivalent to the NASA baseline, you are assuming orbital cryogenic propellant transfer will be practical. That's a key point, since NASA has been very reluctant to design a baseline that depends on it.

Finally, you need a plan B: how would you carry out operations if cryogenic propellant transfer is not practical. One option would be using two 232s and EOR: one lifting the EDS, the other the CEV and LSAM.

Will
Title: Re: DIRECT v2.0
Post by: kraisee on 05/24/2007 04:19 PM
Quote
veedriver22 - 23/5/2007  5:06 PM

The CEV not being able to perform a LOI could be a big deal.

Agreed.   The Ares-I is only capable of placing a 20,186kg CEV into 120x120nm circular orbit.   This removes any chance of adding extra propellant for any purpose, such as LOI burns.

With approximately 46mT (in CLV configuration) of lift capability, the Jupiter-120 has the option to lift CEV's massing a lot more.   It allows for a CEV to be designed which *can* perform an LOI burn.

The limitation is not on the CEV - the limitiation is on the launch vehcile launching the CEV.   Ares-I imposes far more stringent limitations on what can be lifted than Jupiter-120.

Ross.
Title: RE: DIRECT v2.0
Post by: anonymous on 05/24/2007 04:33 PM
I've been lurking for a long time, but this is my first post so I'll give a little bit of background about where I'm coming from before I get onto my thoughts about DIRECT v2.0.

I think it's a huge waste of money to go back to the Moon with present technology that's not as hopelessly expensive as Apollo, but not that far short. Human spaceflight is just a kind of porn until the costs can be brought way down, as Elon Musk is trying to make a start on.

That's my political view. Personally, I like space porn and would enjoy watching astronauts on the Moon because I missed it the first time around. I know, though, that the vast majority of people aren't interested. They weren't even interested in Apollo after the first landing. Going back to the Moon isn't exciting. Even real human spaceflight enthusiasts only see it as a stepping stone to Mars.

Others have written about the budgetary challenges facing VSE and particularly the Ares plan. Ross's political analysis behind DIRECT is spot on. It's almost impossible to imagine that in 2016 or whenever Ares I finally flies (if it ever does) there will be enthusiasm for investing further billions in Ares V. The current plan is politically doomed, probably not long after 2008. Politically, the only slender hope for VSE is DIRECT or a variant. Even then, the cost of the LSAM will probably kill it.

I'm not an engineer, but when I read the DIRECT v2.0 proposal I was struck that Jupiter 232's payload to LEO seemed high compared to other LVs of that size in ESAS and even compared to DIRECT 1.0 Heavy. I remembered how DIRECT v1.0 turned out to be too good to be true. I was also worried about relying on propellant transfer in space.

JIS does come across as a curmudgeon, but he turned out to be dead right in his criticisms of DIRECT v1.0. He obviously does know a lot about what he's talking about. I remember how he said the regen RS-68 couldn't achieve the claimed ISP and was dismissed. Now he's saying that the upper stage has too little mass I find that very credible. He's also raised concerns about propellant transfer in space. Now Will is doing the same.

I remember that a few months ago Ross wrote that the *only* way to go was with two of what now is called the Jupiter-232. What happened to make him change his mind and decide that it could be done with a 232 and a 120?

In the proposal,  2x Jupiter-232s with LOR-LOR and no propellant transfer can support a 50MT LSAM. What's the equivalent figure with 2x Jupiter-232s using EOR-LOR as Will suggests?
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/24/2007 04:38 PM
If they are stranded in lunar orbit is Houston going to just radio to them & thank them for their service?   No they wouldn’t.   They would pull out all the stops & do something/anything to try to save them.  

 If they are stranded on the surface & the next mission is carried out,  how are they going to get twice the crew back to the CEV,  and back home in the CEV with twice the number of crew?

 The way to cover as many situations as possible would be to have an emergency LSAM on the moon with emergency supplies.  It would be landed unmanned & would be there in case of emergencies.   I think the ascent stage uses hypergolics, so it could stay there for long periods.   If the astronauts become stranded they would make their way to the emergency LSAM.   Of course that assumes they have a  method of getting there from their original landing location.  

  If they somehow become stranded in lunar orbit you launch the emergency LSAM ascent stage which would be unmanned.   Assuming that it could meet up with crew in orbit, they would use the supplies stored in the emergency LSAM to survive until help arrives.  

 What do you do now?  Do you send another crew?   I don’t know if that makes any sense.   Are they going to perform their scheduled mission, and then pick up the stranded crew?  I doubt that is practical.   Plus on the return trip the CEV would somehow have to support 2 full crews (and reenter with them on board).

  So were back to a rescue mission.   Send an unmanned CEV on a mission to pick them up an get them home.   To do this you will either have to have a CEV that can perform a LOI burn,  or send a CEV with another LSAM.     Having such a limited CEV service module just seems like a bad idea.    And this is not the only rescue scenario that you could perform if you had a more capable service module, which would be possible with direct.      
Title: Re: DIRECT v2.0
Post by: kraisee on 05/24/2007 05:24 PM
Quote
Will - 24/5/2007  9:41 AM

It's probably true that staging like 232 is superior for a lunar mission, if only on the basis of simplicity. That doesn't explain why 232 has superior LEO payload to LV-29: one would expect the reverse.

Will, you do make a good point, that the LV-29's 91.9mT performance is without an EDS.   Quick back-of-the-envelope calculations would suggest that payload performance would actually climb to about 132mT with a suitable EDS on top.   But that middle stage adds a whole extra layer of dangerous events: 4 more air-starting engines, one extra separation, greater vehicle height, none of which are helpful.

The LV-29, without that gargantuan 4-engined upper stage, is fairly close to Jupiter-232's Core.

The middle stage is unnecessary though.   Placing an EDS straight on the Core vehicle offers sufficient performance for the Lunar requirement and is actually more optimal in configuration.

As for the "expectation" of different results, that's a subjective thing.   It is never going to be a substitute for carefully calculated results.

While the bigger Upper Stage on LV-29 offers lower performance than J-232, it is designed to lift an EDS on top.   It must thus have higher performance than the EDS itself, and must mass more because it must support all the extra weight on top.   The LV-29 U/S must mass somewhere about 32 tons at burnout.

Jupiter-232 is not launching a ~300 ton EDS & ~100 ton payload on top of the U/S, only the ~100 ton payload.   This means you need considerably less thrust (actually less than half)  to achieve the same performance.   This means that with half the number of engines you will actually get slightly better performance in real terms.   This allows you to reduce the mass of the support structures too.   Additionally, and probably most importantly, you also don't need propellant for 4 engines - only two.   Together, you can roughly halve the entire weight of the Upper Stage and still get similar results.

In our case, we are also using Centaur-derived technology to improve performance a little more too, and together that achieves 108mT of lift performance from the 232.

Just for the record, the performance simulations we have produced have already been validated in a number of different environments.   We are using professional trajectory optimization tools throughout the process (both v1 and v2)   I personally have tools sourced from the European Space Agency for calculating these trajectories, and can run a basic simulation in about 30 minutes, with a fully optimized analysis ready, often, in just a few hours.   Stephen has POST, which is even higher fidelity and is the tool NASA uses.   We have other people in the larger DIRECT team who also have POST, and some of those have access to the original ESAS analysis too.

The DIRECT vehicles are continually being compared to existing data sets, to ensure that we stay well within the same margins.   Jupiter-120 and Jupiter-232 achieve every single one of the ESAS Ground Rules and Assumptions (actually with 2% higher margins than ESAS used, to give us extra safety margin).   We even achieve the <600psf max-Q targets which Ares-I doesn't even get close to achieving.

BTW, all Jupiter performance figures are NET, not Gross.   Gross is fairly meaningless, so we have never been interested in it.


There are a number of "backup" plans available with the lift capability provided by the Jupiter LV's.

For example, one option, if propellant transfer is not allowable, is to fly the "minimized ascent" (see below) LSAM's cargo pallet with the CEV.   The CEV and cargo perform the TLI still attached to the Spacecraft Adapter.   On the journey to the moon, the CEV separates and extracts the cargo.   It performs LOI and rendezvous with a ~50mT LSAM already in LLO.   The ~20mT cargo pallet is then attached to the LSAM, next to the Ascent Module, and the CEV docks.   There are a number of different procedural approaches to doing this attachment/docking, so I will deliberately refrain from specifying a preference at this time.

This allows non-dangerous cargo to fly with the CEV, yet still allows the full performance of the 2x232 LOR-LOR approach to be utilized.

There are many such options available - but all of these options depend on sufficient lift performance.   Ares-I's performance being in the mix denies all of these alternatives.

Ross.


Minimized Ascent LSAM - from NASA Tony Lavoie Exploration Conference Presentation, 2006
Title: Re: DIRECT v2.0
Post by: MKremer on 05/24/2007 05:45 PM
Quote
veedriver22
If they are stranded in lunar orbit is Houston going to just radio to them & thank them for their service? No they wouldn’t. They would pull out all the stops & do something/anything to try to save them.

If they are stranded on the surface & the next mission is carried out, how are they going to get twice the crew back to the CEV, and back home in the CEV with twice the number of crew?

Totally impractical (extra people and time required for: hardware/engineering/VAB/pad-prep logistics, extra mission pre-flight planning and programming, simulations/training for totally separate flight operations staff and console operators/back room crews, emergency range setup and range safety prep training and operations, emergency last-minute flight mission planning and full document prep's/printing specific to the circumstances/orbital/seasonal parameters, etc.)

Not to mention the horrific extra expenses for all that plus having any and all CEV/AI & LSAM/AV LON hardware not only in the pipeline but almost ready to fly before each manned mission launches. There just wouldn't be the necessary money/time/personnel to do all that unless you could convince both the NASA Administration and Congress all that was totally necessary and increase each yearly budget to cover all the extra costs involved and totally rewrite all the lunar mission plans and hardware requirements.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/24/2007 06:42 PM
You would build an launcher & CEV specifically for rescue & keep it on standby.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/24/2007 07:18 PM
Quote
anonymous - 24/5/2007  12:33 PM

I've been lurking for a long time, but this is my first post so I'll give a little bit of background about where I'm coming from before I get onto my thoughts about DIRECT v2.0.

Fair critical view.   This is the sort of thing we are looking for here, to help keep us on the rails correctly and soundly.   Thank-you.

There is a lot to deal with here, so let me just pile in...

I agree with your assessment regarding political will.   Ares-I is too small to impress anyone, let alone Congress.   Once it has completed its fight to be funded, NASA then wants billions for Ares-V and yet more billions for the EDS and also for the LSAM.   Congress isn't likely to be hugely enthusiastic having waited 12 years for "just" Ares-I...

For the record, we have data in hand, which we can't release, which appears to *prove* that the original RS-68 Regen performance figures we used were in fact pretty close to what *is* achievable from a RS-68 with an optimized regenerative nozzle.   Our 435s figure is within 5s vac Isp of what can be done.

Yet we have specifically avoided all such issues, not because they aren't technically achievable, but because they are targets for opponents to grab hold of.   If we avoid all of those issues, there's not much which can be fought against.

The U/S is actually well within margins for a Centaur-derived (ICES) design.   This is a massively more efficient design, and is proven already on Atlas launchers, than the designs used by the ESAS.   Believe me, we were caught out once before, and we have been very careful not to risk that again!   Our estimates are conservative at every level.   The current tanking is actually designed to be able to handle all of the ascent propellant, and to also contain 108mT of propellant.   This allows the full performance to be utilized for an orbital fuel depot.   It is actually larger than it needs to be for just Lunar missions, so there are actually immediate weight savings available if the priority is for maximum Lunar performance.

Propellant Transfer.   This is routinely done on ISS - with inherently more dangerous chemicals than LOX/LH2.   Hydrazine (AKA UDMH or N2H4) and Nitrogen tetroxide (N2O4) are combustible if they just come into contact with each other.   They don't require heat, pressure or an ignition source - merely touch.   LOX/LH2 require an independant ignition source even if they are mixed together.   LOX/LH2 are tricky though, because they are cryogenic liquids.   This adds complexity, but it is nothing which can't be done if planned correctly from the start.   Thermal conditioning for the piping and valves is needed before the transfer, and launch pad-like disconnects are required when the modules are disconnected.   But cryo propellant loading can be routinely done with the correct design and procedures.

One alternative (outside of the real scope of DIRECT) to make propellant transfer even safer for the CEV & LSAM would be to use Methane/LOX.   The Methane does not require cryo storage, and actually offers some mass benefits due to its density too.   But Ares-I and Ares-V are already sucking-up so much budget that NASA has already been forced to abandon developing Methane engines.   With only one LV to develop instead of two, NASA should have funds to do this after all, and this is immediately an advantage for Mars missions later.

The key vehicle in the DIRECT proposal is indeed the J-232.   The decision to use the J-120 configuration was made in a bid to speed the first flight of the CEV.   The longest lead item for the J-232 is the J-2X needed for the EDS.   The J-120 doesn't have to wait for that.

Once the J-232 is made available, there is no reason to abandon the J-120.   It uses precisely the same parts and the parts are, in fact, designed to be interchangable.   It costs no more to keep J-120 available, yet offers a cheaper LV than J-232 for all payloads massing less than 48mT.   Many LEO missions can be flown without needing the costs of the EDS and the third MPS unit.   Also, the J-120, having fewer stages and fewer engines is going to be safer for crew launch operations - at least until sufficient confidence in all the systems has been established.

DIRECT v2.0's architecture has been designed to scale, in a two or three-step fashion, to an all J-232 approach for manned Lunar missions.   The J-120 simply offers the option of using a mid-way stepping-stone approach, and a cheaper vehicle for most LEO purposes.

Ultimately, whether we are talking Ares, or Jupiter, crews will *have* to fly on the Heavy Lift variant.   Eventually, a reusable lunar lander will be made, fuelled by In-Situ Resources found on the Lunar surface.   Crews will be launched from Earth aboard a single large vehicle, to rendezvous in Lunar orbit with that Lunar "taxi".   Be it Ares-V, or Jupiter-232, that vehicle will need a CEV and an EDS to get the crews to Lunar orbit.   This is the inevitable conclusion to the path the VSE is following, and either vehicle supports this, but Ares-V is more expensive.


As for 2x J-232's launching an EOR-LOR mission with no propellant transfer.   This, I have to say, has not been modelled fully, because LOR-LOR offers performance advantages if you are flying two EDS modules on two different flights.   All I can offer in this particular message are approximate answers.   Given that all I'm going to do is a "rough" work on this, here is a basic outline:-

Lift capability to 120nm circular: Cargo flight: 106.2mT, Crew flight: 105.0mT. (both plus EDS).

Additional Assumptions:
* CEV masses 20,186kg (same as Ares-I).
* EDS Burnout mass: 23,062kg
* Second EDS is unavailable for TLI on EOR profile
* No Propellant Transfer between CEV -> LSAM
* No Propellant Transfer between EDS-1 -> EDS-2
* "Rule of Thumb": TLI Using LOX/LH2 & 448s Isp, Propellant : Total Mass ratio must be 1 : 0.96 (1 ton propellant required for every 960kg of actual hardware).

So, we start with an initial breakdown:

Total lift capability (one EDS retained): 234.2mT.

Max Hardware to TLI: 114.7mT
Max Propellant for TLI: 119.5mT.   Note, this is 11.4mT more than the 232 is currently designed to carry, so without propellant transfer we immediately have to adjust these numbers down (sad waste):
-

Adjusted Total lift capability (one EDS retained): 211.8mT.

Adjusted Max Hardware to TLI: 103.7mT.
Adjusted Max Propellant for TLI: 108.1mT.

Unallocated hardware: 103.7mT - 20.2mT (CEV) = 83.5mT.

This looks pretty good to me for an LSAM Gross GLOW mass.   4mT is the harness which supports the LSAM on top of the EDS.   Effectively results in an LSAM massing about 66.2mT when it reaches LLO (LSAM performs LOI), but this would require the more risky LSAM > EDS docking in LEO (both EDS' need the harness) which we have deleted since v1.0 of DIRECT.

It's an option, but also isn't actually as safe as as an LOR-LOR profile using the same hardware.   And even that can bypass the issue of propellant transfer by transferring "safe" inert cargo from the CEV to the LSAM in LLO instead of propellant.

It's not bad, certainly an improvement over Ares-I/V - but the performance isn't as good as a 2x 232 LOR-LOR approach.   And there aren't really many alternatives that I can see so far without some form of propellant transfer.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/24/2007 07:37 PM
These rescue options are simplified under the DIRECT architecture.   Fundamentally, any Jupiter Core Stage & booster set can be used for any mission at all.   The only hardware which would have to be held aside is an EDS, Spacecraft Adapter and CEV to go on top in case of emergency.   These are all standard elements used on regular missions, and are a totally standard equipment flown regularly on the Jupiter-232 CLV configuration we are planning to use anyway.   So no new hardware is required for this special mission at all.

In the case of Ares, an Ares-I is currently required to lift the CEV and an Ares-V is also required to lift the EDS to support a rescue mission.   No third configuration exists currently with the CEV on top of the Ares-V, and none of the launch towers currently being designed appear to support access to a CEV at that height either.   Additionally, I'm unaware of any other way to connect a CEV to an EDS other than by using a very expensive LSAM in between.   For a crew trapped on a stranded CEV, this doesn't seem to be a good way to provide rescue capabilities.

I'm not sure there actually are any realistic options for launching two Ares vehicles in the time necessary for rescuing a crew 'lost' on a Lunar mission.

I think this may actually be a very critical safety point in DIRECT's favour because whatever the vehicle being prepared next, it is always going to be suitable to use for rescue ops.

Ross.
Title: RE: DIRECT v2.0
Post by: SolarPowered on 05/24/2007 08:07 PM
Quote
kraisee - 24/5/2007  12:18 PM
And there aren't really many alternatives that I can see so far without some form of propellant transfer.

Ross.
It seems to me that any serious lunar or planetary program is going to have to master orbital propellant transfer.  The other alternative is to have LVs that are so huge that you can launch entire missions, completely fueled, in one launch.  Trying to divide up missions into equally-sized, fully-fueled pieces that can be separately launched would seriously constrain what you are able to do.

I consider propellant transfer to be a fundamental ability, rather like the ability to rendezvous in orbit.  We did some Gemini missions to verify that we could do a successful rendezvous; we now need to master propellant transfer.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/24/2007 08:12 PM
Actually there is one other alternative.   A way to bolt together propellant modules next to each other.

Imagine a cluster of 3 or 7 EDS modules attached together in orbit.   You wouldn't have to transfer propellant at all.

It's an idea I've been toying with, but I'm a touch nervous about parallel rendezvous & docking operations between two or more modules each containing 100 tons of highly explosive propellant, but which only have 1/4" thick skins.

Ross.
Title: RE: DIRECT v2.0
Post by: Will on 05/24/2007 08:42 PM
Ross writes:

"LOX/LH2 are tricky though, because they are cryogenic liquids. This adds complexity, but it is nothing which can't be done if planned correctly from the start."

The key point is that you can't use the techniques that have been proven for orbital transfer of storables, which involve flexible bladders within the tanks. At cryogenic temperatures, the bladders in use for storables shatter like glass.

So all you need in addition to the complications inherent in ground based cryogenic transfer, is a way to keep the propellant settled long enough to pump it from one tank to another. It's obviously possible: the simple way is to use propellant to create thrust while you run the pumps. How much propellant do you need to burn, and how much mass for the power source to run the pumps? Nobody knows for sure because as far as I know it's never been done in orbit. But it could be a significant penalty.

Will

Title: RE: DIRECT v2.0
Post by: jongoff on 05/24/2007 08:50 PM
SolarPowered,
Quote
It seems to me that any serious lunar or planetary program is going to have to master orbital propellant transfer.  The other alternative is to have LVs that are so huge that you can launch entire missions, completely fueled, in one launch.  Trying to divide up missions into equally-sized, fully-fueled pieces that can be separately launched would seriously constrain what you are able to do.

I consider propellant transfer to be a fundamental ability, rather like the ability to rendezvous in orbit.  We did some Gemini missions to verify that we could do a successful rendezvous; we now need to master propellant transfer.

I'm glad I'm not the only one who sees it that way.  While they could've done Apollo without the ability to do orbital rendezvous, it would've been far more expensive, would've required much bigger boosters, and would've taken a lot longer than was necessary (while running the risk of the whole thing getting canceled at some point).  Orbital cryogenic propellant transfer seems to be the technology we really need to master now to make lunar transportation realistic.

Of course though, once you go with orbital propellant transfer...all of the sudden even a more affordable HLV like DIRECT starts looking less and less necessary.  Ares I/V even more so.  Which is why as far as NASA is concerned orbital propellant transfer is "far too tough to risk putting on the critical path".

I do find it ironic though that the technology that makes DIRECT the most competitive with Ares I/V is also the one that makes the whole case for Shuttle Derived HLVs look questionable.

~Jon
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/24/2007 09:18 PM
Could not the stack be put into a spin or tumble such that centrifugal force settles the liquids?
Title: Re: DIRECT v2.0
Post by: MKremer on 05/24/2007 09:28 PM
Quote
Lee Jay - 24/5/2007  4:18 PM

Could not the stack be put into a spin or tumble such that centrifugal force settles the liquids?
You're kidding, right?
Title: RE: DIRECT v2.0
Post by: Jim on 05/24/2007 09:31 PM
Quote
Will - 24/5/2007  4:42 PM

Ross writes:

"LOX/LH2 are tricky though, because they are cryogenic liquids. This adds complexity, but it is nothing which can't be done if planned correctly from the start."

The key point is that you can't use the techniques that have been proven for orbital transfer of storables, which involve flexible bladders within the tanks. At cryogenic temperatures, the bladders in use for storables shatter like glass.

So all you need in addition to the complications inherent in ground based cryogenic transfer, is a way to keep the propellant settled long enough to pump it from one tank to another. It's obviously possible: the simple way is to use propellant to create thrust while you run the pumps. How much propellant do you need to burn, and how much mass for the power source to run the pumps? Nobody knows for sure because as far as I know it's never been done in orbit. But it could be a significant penalty.

Will


This isn't a big deal.   Centaur does it every time it restarts in orbit.   Small thrusters are part of the Centaur and burn before every engine start.
Title: Re: DIRECT v2.0
Post by: on 05/24/2007 09:58 PM

Quote
kraisee - 24/5/2007  3:12 PM  Actually there is one other alternative.   A way to bolt together propellant modules next to each other.  Imagine a cluster of 3 or 7 EDS modules attached together in orbit.   You wouldn't have to transfer propellant at all.  It's an idea I've been toying with, but I'm a touch nervous about parallel rendezvous & docking operations between two or more modules each containing 100 tons of highly explosive propellant, but which only have 1/4" thick skins.  Ross.

Autonomous rendezvous & docking is dangerous primarily for the human risk. If you assemble a cluster, you'd want to assemble similar mass objects (ones into twos, twos into fours, ...), and then add your CEV/LSAM axially last.

As to the tolerances and safety factors, there are many ways to make this acceptable.

I think this is a much better idea than cryogenic transfer. Also, you could conceivably handle boil-off loss by adding another module to make up for the loss.  

Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/24/2007 10:00 PM
Quote
MKremer - 24/5/2007  3:28 PM

Quote
Lee Jay - 24/5/2007  4:18 PM

Could not the stack be put into a spin or tumble such that centrifugal force settles the liquids?
You're kidding, right?

Thanks for the helpful information.
Title: RE: DIRECT v2.0
Post by: jongoff on 05/24/2007 10:28 PM
Will,
Quote
So all you need in addition to the complications inherent in ground based cryogenic transfer, is a way to keep the propellant settled long enough to pump it from one tank to another. It's obviously possible: the simple way is to use propellant to create thrust while you run the pumps. How much propellant do you need to burn, and how much mass for the power source to run the pumps? Nobody knows for sure because as far as I know it's never been done in orbit. But it could be a significant penalty.

You mostly need enough force to overwhelm any perturbations and firmly settle the propellant.  If you can afford to take a little time (ie 30min-a couple of hours), this can be done with tens of microgees of acceleration.  There are lots of ways to skin the cat, but the LM guys think that just propulsively venting the LH2 boiloff should be more than adequate.  I've been investigating a couple of other alternatives.

~Jon
Title: Re: DIRECT v2.0
Post by: jongoff on 05/24/2007 10:31 PM
Quote
MKremer - 24/5/2007  2:28 PM

Quote
Lee Jay - 24/5/2007  4:18 PM

Could not the stack be put into a spin or tumble such that centrifugal force settles the liquids?
You're kidding, right?

It's not entirely crazy.  A slow, controlled, end over end rotation could settle propellants.  You'd only need some tiny fraction of an RPM to make it work...but there are other ways to skin the cat.

~Jon
Title: Re: DIRECT v2.0
Post by: jongoff on 05/24/2007 10:38 PM
Nobodyofconsequence,
Quote
Autonomous rendezvous & docking is dangerous primarily for the human risk. If you assemble a cluster, you'd want to assemble similar mass objects (ones into twos, twos into fours, ...), and then add your CEV/LSAM axially last. As to the tolerances and safety factors, there are many ways to make this acceptable. I think this is a much better idea than cryogenic transfer. Also, you could conceivably handle boil-off loss by adding another module to make up for the loss.

Honestly, I think that cryogenic propellant transfer will be easier in the near term, but this idea isn't too bad either.  Honestly, I think the two ideas go well together.  Dry launch the individual modules, and then add additional parallel stages on-orbit as needed.  That would allow truly massive missions to be sent out without requiring much in the way of new hardware beyond a first generation Lunar Transfer Vehicle/EDS.

~Jon
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/24/2007 10:39 PM
Quote
jongoff - 24/5/2007  4:31 PM

Quote
MKremer - 24/5/2007  2:28 PM

Quote
Lee Jay - 24/5/2007  4:18 PM

Could not the stack be put into a spin or tumble such that centrifugal force settles the liquids?
You're kidding, right?

It's not entirely crazy.  A slow, controlled, end over end rotation could settle propellants.  You'd only need some tiny fraction of an RPM to make it work...but there are other ways to skin the cat.

~Jon

You're other post said 10s of micro-g's.  Assuming 0.0005 m/s^2 and a 20 meter stack, you'd need to rotate only once every 15 minutes or so.

Lee Jay
Title: Re: DIRECT v2.0
Post by: Thorny on 05/24/2007 10:42 PM
Quote
Jim - 24/5/2007  8:28 AM

It isn't that easy.
S-IVB's were designed and scarred for it from the beginning.    the Ares upperstage isn't design for it.

No posigrade thrusters, no zero g vent system, no recirculation system, stage insulation not designed for onorbit, no onorbit cooling for avionics and many more


OAMS flew on the Gemini spacecraft

BTW First stage roll control is on the interstage.


You're right. It was the APS (Auxillary Propulsion System) on the S-IVB.

Since Ares I-S2 is still only in design, how hard would it be to add the necessary scarring for orbital attitude control? That would seem to be a small price to pay for potential Ares IV or dual Ares I missions in the future.

Since roll control is on the interstage, how are they going to control roll with a single-engine during stage 2?



Title: RE: DIRECT v2.0
Post by: kraisee on 05/24/2007 10:53 PM
Quote
jongoff - 24/5/2007  4:50 PM

I do find it ironic though that the technology that makes DIRECT the most competitive with Ares I/V is also the one that makes the whole case for Shuttle Derived HLVs look questionable.

~Jon

Jon, there is an issue with that thought though - scale.

A single Jupiter-232 can launch the equivalent of about 4 "Heavy" EELV's.   The question is, does it cost more?   And what about economies of scale?

Given the expected routine flight rates for both classes of vehicle, propellant supply would still be massively cheaper on the larger vehicle.   Let me explain.

Some basic assumptions to start explaining with:-

* 2 Manned Lunar missions per year (175mT IMLEO) per year
* 2 Cargo-only Lunar Missions per year (150mT IMLEO) per year
* 2 ISS Crew Rotations per year (20mT) per year
* 8 EELV flights average delivering DoD/NASA/Commercial payloads anyway per year.


The fixed costs for Jupiter would be between $900 - 1,200 per year.   Using most of the existing STS costs to derive our calculations, individual flight costs are expected to be $120-140m for a Jupiter-120 and $200-230m for a J-232 in the normal flight rates as listed above.

The costs are a little more difficult to assess for the military funded EELV program though.   Fixed costs for each of the EELV programs is known to be roughly $500m per year.

The individual flight cost can be derived from a careful study of the DoD SAR documentation for the program.   I spent a LONG time working it out a couple of years ago for an NSF article which I never published, but here are the results.   Interestingly, they are very close to those presented on astronautix.com.

* A Small EELV (example: Atlas 401, Delta-IV Medium, <15mT to LEO) is roughly $105m.
* A Medium (example: Atlas-V 551, Delta-IV Medium+ 5,2, 15-20mT to LEO) is approximately $130m.
* A Heavy (example: Atlas-V Heavy, Delta-IV Heavy, 20-30mT to LEO) is $190m.


Assuming normal economies of scale, where doubling production results in a 10% drop in unit cost, re-iteratively (2x = 90%, 4x = 89%, 8x = 73%) we can start making some comparisons.

Ignoring Fixed Costs for a moment, this translates to:

* Small EELV: $8,750 per kg to LEO
* Medium EELV: $6,500 per kg to LEO
* Heavy EELV: $7,303 per kg to LEO
* Jupiter-120: $2,916 per kg to LEO
* Jupiter-232: $2,129 per kg to LEO


Assuming 4 J-120's and 4 J-232's per year, and factoring in the fixed costs, the total cost would be $2,680m, launching a total of ~624,400kg.   That's about $4,292 per kg to LEO.

Assuming EELV's of the same type (Atlas or Delta, not both) and assuming a 'typical' distribution of say 3 Small, 3 Medium, 2 Heavy per year as 'regular', and factoring in the fixed costs of just one EELV program, the total cost would be $1,585m launching a total of ~148,000kg.   That's about $10,709 per kg to LEO.


For one single 100mT propellant flight, you would need about 4 Heavy EELV's on top of this, costing ~$171m each (I'm saying these 4 extra units equates to "doubling" to get the best out of the economies of scale, although it's only really half way there, I'm being kind!) and this 100mT of propellant costs $684m to launch.

One extra J-232 can do the same for $230m - roughly 1/3rd of the cost.


To get the EELV economies of scale down to this level, you'd have to halve costs at least.   Halving the costs requires 128 times the production numbers currently being achieved, or about 1,000 EELV launches per year - that's about three every single day of the year!

And that doesn't account for the fact that if that quantity of payload were ever needed, economies of scale also apply to the Jupiter vehicles too.   If 20,000 tons of material needed launching, you could do it on 185 Jupiter-232's, and that would drop unit costs down to about 60% of starting levels too.   EELV's don't ever catch up because of economies of scale.

There is no reasonable point where economies of scale allow the $/kg ratio of EELV match the raw Heavy Lift capability of the basic Shuttle Stack once you take the orbiter out of the equation - the Jupiter.

The Ares-I's $/kg can certainly be beaten by EELV, but that's a different topic and it's really for someone at MSFC to go handle.

Ross.
Title: Re: DIRECT v2.0
Post by: MKremer on 05/24/2007 11:00 PM
Quote
Lee Jay - 24/5/2007  5:00 PM

Quote
MKremer - 24/5/2007  3:28 PM

Quote
Lee Jay - 24/5/2007  4:18 PM

Could not the stack be put into a spin or tumble such that centrifugal force settles the liquids?
You're kidding, right?

Thanks for the helpful information.
At least think it through completely. OK, you establish a slow rotation to collect/settle the fuel at the end you need it at. Now what do you do?

It would turn out that you'd have to do all your fuel transfers during the rotation, and during that time you're 'stuck' until you either complete the transfer, or have to interrupt it (for whatever reason) and spend fuel/time to stop the rotation and resolve things, then re-start your rotation and fuel transfers again, then stop the rotation on completion.

That sure seems to me to be a lot more risk/time/effort than more straightforward ullage thrusters to settle the fuel for transfer, and also giving you much more simpler control/options for whatever fuelling disruptions that may occur.


Title: Re: DIRECT v2.0
Post by: kraisee on 05/24/2007 11:05 PM
Just an aside, Cranfield jointed thrusters would provide an enormous amount of control authority during such a manoeuvre as this.

Ross.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/24/2007 11:07 PM
I'm not experienced enough to determine which approach would be optimal for each possible stack configuration and mission profile.  I'm just saying it seems to me that it would be possible to do this with rotation instead of thrust if there were reason to do so.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/24/2007 11:13 PM
Lee Jay,
I'm thinking that the centrifugal forces of rotation would probably force the propellant to the opposite end of the tanks (engine end) for transferring to a vehicle connected at the "top".   This would require longer transfer lines and larger pumps, which would represent a larger weight penalty.

I'm not sure which would trade better, more propellant for thrusters, or this heavier "plumbing".

If the centrifugal force could maybe be used to passively feed the propellant across, it might be the safer option, but I think the engineers would prefer not to spin the whole stack in this fashion and would opt to provide an active control system (thrusters) to generate all the forces required.

This would make for an interesting trade study none-the-less, especially given that spinning a vehicle like this is a real-world option for Mars-bound vehicles later.

Ross.
Title: RE: DIRECT v2.0
Post by: RedSky on 05/24/2007 11:32 PM
What with nearly 3000 hits on directlauncher.com since version 2...  people certainly have been looking in.  Here's a reference to Jupiter 120 on some blog I came across...

http://chairforceengineer.blogspot.com/2007/05/whats-up-dock.html
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/24/2007 11:56 PM
Quote
kraisee - 24/5/2007  5:13 PM
This would make for an interesting trade study none-the-less, especially given that spinning a vehicle like this is a real-world option for Mars-bound vehicles later.
Ross.

Sure.  As I said, I have no idea which would come out ahead given the wide variety of vehicle configurations that can be dreamt up.  As for control and preferences, the RPM seems to be repeatable and reliable for the Shuttle.  Given the number of spin-stabilized objects we have launched, I have little doubt that that approach could be made to work if there were a reason to do so.

There are lots of pretty heavy engineering, design, manufacturing, and operational challenges for a human flight to the moon.  Personally, I don't see propellant transfer as one of the high-risk issues.  It's not one of the trivial ones either, it's somewhere in the middle.  If there's a good reason to do it, they'll do it.  I wouldn't give up a major architecture improvement over this issue.
Title: RE: DIRECT v2.0
Post by: veedriver22 on 05/25/2007 12:10 AM
Quote
RedSky - 24/5/2007  6:32 PM

What with nearly 3000 hits on directlauncher.com since version 2...  people certainly have been looking in.  Here's a reference to Jupiter 120 on some blog I came across...

http://chairforceengineer.blogspot.com/2007/05/whats-up-dock.html

 What the article describes is precious.  They put a docking ring on JWST that an Ares launched CEV can't reach.   But a Direct launched CEV could possibly do it.
Title: RE: DIRECT v2.0
Post by: Will on 05/25/2007 12:33 AM
Jim writes, re. settling propellant in orbit:

"This isn't a big deal. Centaur does it every time it restarts in orbit. Small thrusters are part of the Centaur and burn before every engine start."

Yes, but only for long enough to start the engine. For propellant transfer, you need to keep the tank settled long enough to pump tons of propellant from one tank to another. And power to run the pump. Some people think it's an easy problem to solve, and they may be right.

Then again, some people thought that artificial gravity was simple: just spin two spacecraft on a tether. How hard can that be?

Will McLean
       
 
 
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/25/2007 12:34 AM
1.  If I recall, someone said that the Ares V EDS has a single J-2X engine to avoid problems with off axis thrust (either due to engine misalignment, engine calibration, or engine out) causing loads through the Orion/LSAM interface.  If I remember right, that sources said that ESAS eliminated multiple-engine EDS concepts due to this constraint, severely limiting first stage options.  How does Direct address this issue?  What if a single-engine EDS were a requirement?

2.  Assuming we only get one chance in the next 30 years to develop a cargo launch vehicle ... what if there was a requirement to deliver 130MT+ to LEO to be compatible with Mars requirements.  How would Direct respond?  

3.  How does the design account for the increase in sensitivity to EDS mass?  This happens when too much of the ascent DV is offloaded to the upper stage, as it appears Jupiter 232 does.  Isn't it much more likely that you will see a 1 lb increase in EDS weight at 45000 lb rather than at 36000 lb ... and would that be a 1 lb reduction in weight delivered to lunar orbit?  This mass sensitivity would hit you during ascent, circularization, ED, and LOI burns.  I'm looking at an older Ares V, so maybe their EDS dry mass is closer to that of Direct now.

4.  What is the calculated LOC/LOM for Jupiter 120?  I think I saw that it meets the hypothetical 1:1000, and it looks like no problem with the number of engines/configuration, but I was wondering if the calcs had been done.

5.  Agree that Direct looks better for LOR than the current configuration.

6.  Have you done a year-by-year available budget analysis like ESAS did?
Title: RE: DIRECT v2.0
Post by: Will on 05/25/2007 12:50 AM
Quote
kraisee - 24/5/2007  2:18 PM


The U/S is actually well within margins for a Centaur-derived (ICES) design.   This is a massively more efficient design, and is proven already on Atlas launchers, than the designs used by the ESAS.  

Ross.


So you are using one set of assumptions for one set of launchers (Direct) and comparing it to a different set of launchers designed under different assumption. For a fair comparison, you would need to calculate how much mass Ares I and V would deliver to orbit if they simply used the same "massively more efficient" upper stage designs.

Will
Title: RE: DIRECT v2.0
Post by: mars.is.wet on 05/25/2007 01:26 AM
Does the massively more efficient upper stage design have the same margins as the Ares V EDS?

It threw me off to see that the Direct EDS had a PMF of .913 ... until I saw it was for ascent propellent only.  

532615/(532615+50843) =0.913

However, the mass fraction calculated for the ascent propellant does not compare fairly to Centaur, Ares V, et al.  If you could do that, you could make a super light stage of almost any size, partially fill it with some amount of propellant to get whatever PMF you wanted.

The gross propellant mass fraction calculated this way is pretty sporty

795077/(795077+44848)=.947

The total PMF for the 2006 Ares V EDS was 0.92, if I recall.

Others
Delta IV - 0.886 (single engine Centaur)
Atlas V - 0.911 (singe engine Centaur)
Titan IV - 0.884 (2 engine Centaur)
Saturn V - 0.889 (single J-2)

Assuming a 3100 lb J2-X and looking at a single-engine stage (for better comparison with the Ares V EDS), the fraction for this stage is even higher

795077/(795077+41748) = 0.95

I'm sure I've messed up the masses somewhere, but where does the precedent for this mass fraction come from?  And if Ares V used the same assumptions, what how would its performance increase, or better yet, how much does Direct suffer from a gross PMF of 0.92 (or lower)?  Looks you lose several MT to LEO at a minimum ...

I guess there have been advances in materials to allow this?

Title: Re: DIRECT v2.0
Post by: kraisee on 05/25/2007 05:24 AM
Quote
mars.is.wet - 24/5/2007  8:34 PM

1.  If I recall, someone said that the Ares V EDS has a single J-2X engine to avoid problems with off axis thrust (either due to engine misalignment, engine calibration, or engine out) causing loads through the Orion/LSAM interface.  If I remember right, that sources said that ESAS eliminated multiple-engine EDS concepts due to this constraint, severely limiting first stage options.  How does Direct address this issue?  What if a single-engine EDS were a requirement?

Firstly thanks for the informed questions.   This is valuable to us :)

There are a number of options.   Firstly, the issue only exists on EOR-LOR mission profiles because on LOR-LOR missions (more suited to Jupiter's performance) the CEV and LSAM fly on separate EDS's and aren't joined anyway.

Secondly, assuming the EOR-LOR missions are required in the early stages to develop initial confidence, you aren't suffering gravity losses on the TLI burn, so you don't have to use both J-2X engines.   You could use one, and keep the other in reserve, using the TVC to address the offset thrust.


Quote
2.  Assuming we only get one chance in the next 30 years to develop a cargo launch vehicle ... what if there was a requirement to deliver 130MT+ to LEO to be compatible with Mars requirements.  How would Direct respond?

Rather than spending something in the ballpark of $20 billion developing another launcher variant, I would suggest simply flying two Jupiters and one flies ~100mT of the needed cargo, and a J-120 brings up the rest.   The extra cost is around $140m.

Additionally, there is no singular item for any Mars mission profile which a 108mT launcher can't lift, but a 130mT lifter can.   The hab module and supplies, the landers, the propulsion module (NEP or whatever) are all well under 108mT as single part items for breaking down to launch individually.

Mars missions, by their nature, are going to be modular and will be launched in four or five flights.   Ares plans to do it in five (4 x Ares-V followed by one Ares-I).   Jupiter plans to also fly five (5 x Jupiter-232).   Both launch ~540mT to LEO.


Quote
3.  How does the design account for the increase in sensitivity to EDS mass?  This happens when too much of the ascent DV is offloaded to the upper stage, as it appears Jupiter 232 does.  Isn't it much more likely that you will see a 1 lb increase in EDS weight at 45000 lb rather than at 36000 lb ... and would that be a 1 lb reduction in weight delivered to lunar orbit?  This mass sensitivity would hit you during ascent, circularization, ED, and LOI burns.  I'm looking at an older Ares V, so maybe their EDS dry mass is closer to that of Direct now.

The EDS mass is optimally suited to the performance of the rest of the vehicle.   It is heavier than it could have been with more efficient MPS on the Core, but it is actually pretty reasonable in the grand scheme of things.

At the time of the TLI, the mass fraction is almost identical to that used by Ares.   Our EDS masses only 588kg more than the Ares-V (thanks to the use of Lockheed-Martin's ICES technology, itself derived from the highly efficient Centaur U/S), so assuming all other factors are the same, we need less than 0.5% extra propellant to offset this difference.   That is a minimal penalty to pay if you're increasing two-flight IMLEO by 42%!

And yes, in answer to a later question, the Jupiter EDS does conform to *all* of the ESAS GRA's.


Quote
4.  What is the calculated LOC/LOM for Jupiter 120?  I think I saw that it meets the hypothetical 1:1000, and it looks like no problem with the number of engines/configuration, but I was wondering if the calcs had been done.

Aside from the discussion of NASA's LOC/LOM numbers, using the same evaluation techniques as ESAS used simply to derive an useful apples-to-apples comparison number which we can use:

Jupiter-120 offers 1:1413 LOC and 1:234 LOM.
Jupiter-232 offers 1:1162 LOC and 1:173 LOM.

For direct comparison the ESAS equivalent determination for the current Ares configurations is:

Ares-I is 1:1918 LOC and 1:433 LOM.
Ares-V is 1:940 LOC and 1:148 LOM.


Quote
5.  Agree that Direct looks better for LOR than the current configuration.

Yes, it is really good at LOR missions.   But as my explanation above demonstrates, even when it is doing a sub-optimal EOR profile, it still manages to produce higher performance than Ares-I/V.


Quote
6.  Have you done a year-by-year available budget analysis like ESAS did?

It is not complete yet, which is why we couldn't include it in the proposal.   In the broadest of strokes, we save about $200-500m every year through 2015 while the LV's are developed, but when our Lunar program begins, the savings go up to around $2,500-3,000m every year after that.   This is mainly because we are no longer developing the Ares-V, and we are only operating one LV program annually, not two.

Our biggest problem is releasing NASA's costs for comparison.   The documentation we know of is all ITAR which means we can't release it.

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/25/2007 05:44 AM
Quote
Will - 24/5/2007  8:50 PM

Quote
kraisee - 24/5/2007  2:18 PM


The U/S is actually well within margins for a Centaur-derived (ICES) design.   This is a massively more efficient design, and is proven already on Atlas launchers, than the designs used by the ESAS.  

Ross.


So you are using one set of assumptions for one set of launchers (Direct) and comparing it to a different set of launchers designed under different assumption. For a fair comparison, you would need to calculate how much mass Ares I and V would deliver to orbit if they simply used the same "massively more efficient" upper stage designs.

Will

Actually, what we are using is data sets from a different source than NASA used.

NASA's ESAS team designed a traditional upper stage for the Ares-V's EDS, with separate tanks, Al-Li structure, traditional modular thrust structure, active cooling systems, exterior plumbing and, frankly, an old-style design philosophy.

The ICES takes a modern look at all of the existing Centaur technologies, which are already proven to be exceptionally efficient, and combines a number of very clever technologies which have previously never been brought together before.

This results in considerably lighter tanking structures (a common bulkhead is one of the most recognizable and obvious examples of this, but certainly not the only factor), lighter thrust structure integrated more closely into the stage, simpler plumbing which also weighs less etc, etc.   They are learning some of these lessons the hard way on Ares-I currently (note the change to common bulkhead design).   But MSFC has a 30-year long history of detesting the Centaur, so I can't imagine they could ever stomach purchasing an ICES licence rather than trying to develop solutions themselves, so they'll always be missing elements on Ares.

DIRECT deliberately ignores these politics in the interests of the program.

Ross.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/25/2007 06:05 AM
Why does Marshall dislike the Centaur so passionately?
Title: RE: DIRECT v2.0
Post by: kraisee on 05/25/2007 06:11 AM
Quote
mars.is.wet - 24/5/2007  9:26 PM

Does the massively more efficient upper stage design have the same margins as the Ares V EDS?

Yes.   It meets all of the ESAS GRA's.


Quote
Others
Delta IV - 0.886 (single engine Centaur)
Atlas V - 0.911 (singe engine Centaur)
Titan IV - 0.884 (2 engine Centaur)
Saturn V - 0.889 (single J-2)

Thanks for providing that list.

It nicely demonstrates what I just said, that the Centaur is noticeably more efficient than more "traditional" upper stages.   NASA used a traditional approach to designing the Ares-V's U/S.   We don't.

The ICES technology takes all of the different lessons learned from Centaur's 40+ years of operation and makes a new, design of stage, which is even more efficient.   And yes, it does use different materials, though not new materials for stages.   ICES doesn't use new hardware, it just uses a lot of different good tech together for the first time.   These technologies have never been brought together in one stage design before.

And actually, the Gross propellant pmf is actually 0.939 for the J-232.


Quote
where does the precedent for this mass fraction come from?

This is based on information from two sources within Lockheed who are familiar with both the ICES systems and the DIRECT proposal.   The two engineers independently offered their assistance privately and we took them up on the offer.   We fed our requirements to them in terms of propellant & payload loads, and provided data about flight environments and they independently provided the relevant data for an ICES stage which would be suitable for DIRECT.   These two sources proved to supply data which was almost an exact match for each other (no real surprise), and so we have confidence in the data we received.   We then added appropriate margins to ensure they were ESAS GRA compatible, and then added our own additional margins for additional safety above-and-beyond ESAS - as we have attempted to do throughout DIRECT's history.   This resulted in the stage data which we incorporated into our simulations, and which was presented in our proposal.

This data is entirely consistent with the scaling of a Centaur stage to this size, when you factor in the ICES technology which reduces mass and also improves boiloff conditions.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/25/2007 06:27 AM
Quote
SolarPowered - 25/5/2007  2:05 AM

Why does Marshall dislike the Centaur so passionately?

There was a massive rivalry in the mid 60's between MSFC who were conceptualizing the S-IV stage for Saturn-1 (later evolved for Sat-1B and Sat-V also) on the one hand and the team producing the Centaur (initially NASA Lewis, later Convair) as an evolution of the pressurized Atlas "balloon" tanking concept.

Both teams wanted to be responsible for the U/S to fly the Lunar missions and there was a lot of ego in the game with such a high profile mission at stake.   MSFC won out in the end and the S-IVB (manufactured by Douglas) flew the lunar missions.

This rivalry was strong and quite bitter at the time, and has never fully died in the 40+ years since.   Some of the current rivalry between Delta-IV and Atlas-V is actually attributable to this event too.

Ross.
Title: Re: DIRECT v2.0
Post by: JIS on 05/25/2007 09:26 AM
Quote
kraisee - 24/5/2007  6:24 PM

Quote
Will - 24/5/2007  9:41 AM

It's probably true that staging like 232 is superior for a lunar mission, if only on the basis of simplicity. That doesn't explain why 232 has superior LEO payload to LV-29: one would expect the reverse.

Will, you do make a good point, that the LV-29's 91.9mT performance is without an EDS.   Quick back-of-the-envelope calculations would suggest that payload performance would actually climb to about 132mT with a suitable EDS on top.

This is not that simple. You can't simply put another stage atop the rocket. LV-29 has similar payload to LEO as Jupiter claims.
I think than LV-29 use HTPB in it's SRB which allows to carry more propellants. That's the main reason why the LV-29 core + SRB is so much heavier (by 110mT) than Jupiter core + SRBs. But I still think that LV-29 is more conservative in the core weight.
Don't forget that Direct v2 study take the core weight "directly" from DIRECT v1 study without allocation any weight growth for higher stresses caused by the aditional engine.
The reason why LV-29 is minor to Jupiter is simple - higher dry mass.    

Quote
While the bigger Upper Stage on LV-29 offers lower performance than J-232, it is designed to lift an EDS on top.   It must thus have higher performance than the EDS itself, and must mass more because it must support all the extra weight on top.   The LV-29 U/S must mass somewhere about 32 tons at burnout.

Jupiter-232 is not launching a ~300 ton EDS & ~100 ton payload on top of the U/S, only the ~100 ton payload.   This means you need considerably less thrust (actually less than half)  to achieve the same performance.   This means that with half the number of engines you will actually get slightly better performance in real terms.   This allows you to reduce the mass of the support structures too.   Additionally, and probably most importantly, you also don't need propellant for 4 engines - only two.   Together, you can roughly halve the entire weight of the Upper Stage and still get similar results.

This is certainly not right assuption. LV-29 carries 108mT payload (this could be anything, even another EDS) on the top. Nothing else. Jupiter-232 claims to carry up to also 108mT payload on the top. The only structural difference is caused by the maximum burnout "g" forces. For LV-29 second stage its 4g's. For Jupiter EDS its much less.

Quote
Just for the record, the performance simulations we have produced have already been validated in a number of different environments.   We are using professional trajectory optimization tools throughout the process (both v1 and v2)

I've put this question before. Who did the structural stress analysis? I suspect Jupiter core, EDS, fairing etc. masses being too low.

Quote
BTW, all Jupiter performance figures are NET, not Gross. Gross is fairly meaningless, so we have never been interested in it.

This is mysterious for me too. Gross payload in ESAS study. I'm starting to think that the "net payload" incorporates some extra payload margin.
Title: RE: DIRECT v2.0
Post by: JIS on 05/25/2007 09:45 AM
Quote
kraisee - 24/5/2007  8:18 PM
As for 2x J-232's launching an EOR-LOR mission with no propellant transfer.   This, I have to say, has not been modelled fully, because LOR-LOR offers performance advantages if you are flying two EDS modules on two different flights.   All I can offer in this particular message are approximate answers.   Given that all I'm going to do is a "rough" work on this, here is a basic outline:-

Lift capability to 120nm circular: Cargo flight: 106.2mT, Crew flight: 105.0mT. (both plus EDS).

Additional Assumptions:
* CEV masses 20,186kg (same as Ares-I).
* EDS Burnout mass: 23,062kg
* Second EDS is unavailable for TLI on EOR profile
* No Propellant Transfer between CEV -> LSAM
* No Propellant Transfer between EDS-1 -> EDS-2
* "Rule of Thumb": TLI Using LOX/LH2 & 448s Isp, Propellant : Total Mass ratio must be 1 : 0.96 (1 ton propellant required for every 960kg of actual hardware).

So, we start with an initial breakdown:

Total lift capability (one EDS retained): 234.2mT.

Max Hardware to TLI: 114.7mT
Max Propellant for TLI: 119.5mT.   Note, this is 11.4mT more than the 232 is currently designed to carry, so without propellant transfer we immediately have to adjust these numbers down (sad waste):
-

Adjusted Total lift capability (one EDS retained): 211.8mT.

Adjusted Max Hardware to TLI: 103.7mT.
Adjusted Max Propellant for TLI: 108.1mT.

Unallocated hardware: 103.7mT - 20.2mT (CEV) = 83.5mT.

This looks pretty good to me for an LSAM Gross GLOW mass.   4mT is the harness which supports the LSAM on top of the EDS.   Effectively results in an LSAM massing about 66.2mT when it reaches LLO (LSAM performs LOI), but this would require the more risky LSAM > EDS docking in LEO (both EDS' need the harness) which we have deleted since v1.0 of DIRECT.

Ross.

Ross, this is a true armchair rocket science. It is good enough for chatting. I hope you are not going to present it anywhere else.
Title: RE: DIRECT v2.0
Post by: JIS on 05/25/2007 10:45 AM
Quote
kraisee - 25/5/2007  7:11 AM

Quote
mars.is.wet - 24/5/2007  9:26 PM

Does the massively more efficient upper stage design have the same margins as the Ares V EDS?

Yes.   It meets all of the ESAS GRA's.


Quote
Others
Delta IV - 0.886 (single engine Centaur)
Atlas V - 0.911 (singe engine Centaur)
Titan IV - 0.884 (2 engine Centaur)
Saturn V - 0.889 (single J-2)

Thanks for providing that list.

It nicely demonstrates what I just said, that the Centaur is noticeably more efficient than more "traditional" upper stages.   NASA used a traditional approach to designing the Ares-V's U/S.   We don't.

The ICES technology takes all of the different lessons learned from Centaur's 40+ years of operation and makes a new, design of stage, which is even more efficient.   And yes, it does use different materials, though not new materials for stages.   ICES doesn't use new hardware, it just uses a lot of different good tech together for the first time.   These technologies have never been brought together in one stage design before.

And actually, the Gross propellant pmf is actually 0.939 for the J-232.

If you want to take only usable propellants against burnout mass then

ESAS EDS is 0.904
Ares V EDS in January 07 is 0.920
Jupiter 232 EDS is 0.938.  

Anyway, this comparsion is samewhat irrelevant as any NASA heavy launcher would use the same technology for EDS. Therefore, I would recommend to use pmf of 0.920 for Jupiter EDS along with J-2X spec for the next DIRECT study version. This would need additional 16klb (7.26mT) to the Jupiter EDS.
Also, you should look at the mass of the other structures.
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/25/2007 11:29 AM
Quote
kraisee - 25/5/2007  1:24 AM

Quote
mars.is.wet - 24/5/2007  8:34 PM

1.  If I recall, someone said that the Ares V EDS has a single J-2X engine to avoid problems with off axis thrust (either due to engine misalignment, engine calibration, or engine out) causing loads through the Orion/LSAM interface.  If I remember right, that sources said that ESAS eliminated multiple-engine EDS concepts due to this constraint, severely limiting first stage options.  How does Direct address this issue?  What if a single-engine EDS were a requirement?

Firstly thanks for the informed questions.   This is valuable to us :)

There are a number of options.   Firstly, the issue only exists on EOR-LOR mission profiles because on LOR-LOR missions (more suited to Jupiter's performance) the CEV and LSAM fly on separate EDS's and aren't joined anyway.

Secondly, assuming the EOR-LOR missions are required in the early stages to develop initial confidence, you aren't suffering gravity losses on the TLI burn, so you don't have to use both J-2X engines.   You could use one, and keep the other in reserve, using the TVC to address the offset thrust.


I don't think this solves the problem that was discussed.  Actually, I'm sure it doesn't.  Docking rings can't take any transverse loads, and aligning 2 engines (or 1 engine for 2 profiles adjusting for c.g. changes) needs to be addressed somehow.  I am pretty sure it is a show stopper.  If you had to go to a single-engine EDS, what is the performance loss?  Does the mission still close?
Title: RE: DIRECT v2.0
Post by: Will on 05/25/2007 12:08 PM
Ross writes:

"And actually, the Gross propellant pmf is actually 0.939 for the J-232."

Ross, I like your proposal overall, but this sort of thing hurts its credibility.  That's a profoundly optimistic mass ratio compared to existing technology. I'll believe it when Lockmart retrofits Centaur to get the obvious benefits of improved payload.

I have to ask why the Centaur design philosophy isn't more popular. It isn't just Boeing: neither Ariane nor the Japanese have been able to get Centaur-like mass ratios in their upper stages. Aren't there some operational penalties and manufacturing complications from trying to get the lowest posible upper stage mass that way?

Will
Title: Re: DIRECT v2.0
Post by: Jim on 05/25/2007 01:00 PM
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Thorny - 24/5/2007  6:42 PM

Since Ares I-S2 is still only in design, how hard would it be to add the necessary scarring for orbital attitude control? That would seem to be a small price to pay for potential Ares IV or dual Ares I missions in the future.

Since roll control is on the interstage, how are they going to control roll with a single-engine during stage 2?


There is a RCS system on the upperstage and it is use for rool control.  But it doesn't have axial thrusters.   But that is minor compared to all the other changes required for "restarting" the uppoerstage

Title: RE: DIRECT v2.0
Post by: Jim on 05/25/2007 01:02 PM
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Will - 24/5/2007  8:33 PM

Jim writes, re. settling propellant in orbit:
 
"This isn't a big deal. Centaur does it every time it restarts in orbit. Small thrusters are part of the Centaur and burn before every engine start."

Yes, but only for long enough to start the engine. For propellant transfer, you need to keep the tank settled long enough to pump tons of propellant from one tank to another. And power to run the pump. Some people think it's an easy problem to solve, and they may be right.
 

No, the thrusters burn thru the whole coast to keep the propellants settled.  As long as the thrusters are on, there is no issue.
Title: RE: DIRECT v2.0
Post by: Jim on 05/25/2007 01:03 PM
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mars.is.wet - 24/5/2007  9:26 PM

Delta IV - 0.886 (single engine Centaur)


D-IV does not have a centaur
Title: RE: DIRECT v2.0
Post by: jongoff on 05/25/2007 02:44 PM
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kraisee - 24/5/2007  11:11 PM

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mars.is.wet - 24/5/2007  9:26 PM
where does the precedent for this mass fraction come from?

This is based on information from two sources within Lockheed who are familiar with both the ICES systems and the DIRECT proposal.   The two engineers independently offered their assistance privately and we took them up on the offer.   We fed our requirements to them in terms of propellant & payload loads, and provided data about flight environments and they independently provided the relevant data for an ICES stage which would be suitable for DIRECT.   These two sources proved to supply data which was almost an exact match for each other (no real surprise), and so we have confidence in the data we received.   We then added appropriate margins to ensure they were ESAS GRA compatible, and then added our own additional margins for additional safety above-and-beyond ESAS - as we have attempted to do throughout DIRECT's history.   This resulted in the stage data which we incorporated into our simulations, and which was presented in our proposal.

This data is entirely consistent with the scaling of a Centaur stage to this size, when you factor in the ICES technology which reduces mass and also improves boiloff conditions.

To add a little more detail to what Ross said (since I've been tangentially involved in that discussion), here are a couple of important details.  First off, as you could see from your own numbers, Centaur is a very efficient stage already.  However if you look at a detailed mass breakdown, it turns out that a good chunk of the dry mass of the centaur stage is taken up in hardware that doesn't really scale with stage size.  For instance, just because you double the amount of propellant, doesn't mean you need to double the size or number of flight computers, or batteries for those computers.

As they modeled all of their various improved Centaur designs they found that there were certain systems that just had a fixed weight, some systems like the tanks that scaled very linearly with the propellant volume, and others that had different scaling laws.  It turns out that even assuming you didn't go with the FSW Li-Al assumed by the ICES team, you could still get much of the mass fraction improvement discussed just by scaling the existing Centaur using existing technologies, since those fixed masses would take up a much smaller amount of the overall system mass.  I can't recall exactly what percentage of the dry mass of a current Centaur is in that fixed mass category, but IIRC I think its over 30%.

Just some thoughts.

~Jon
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/25/2007 04:00 PM
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kraisee - 24/5/2007  11:27 PM

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SolarPowered - 25/5/2007  2:05 AM

Why does Marshall dislike the Centaur so passionately?

There was a massive rivalry in the mid 60's between MSFC who were conceptualizing the S-IV stage for Saturn-1 (later evolved for Sat-1B and Sat-V also) on the one hand and the team producing the Centaur (initially NASA Lewis, later Convair) as an evolution of the pressurized Atlas "balloon" tanking concept.
...

This rivalry was strong and quite bitter at the time, and has never fully died in the 40+ years since.   Some of the current rivalry between Delta-IV and Atlas-V is actually attributable to this event too.

Ross.
Thanks for the expanation.  It sounds like these guys have been at it longer than the Hatfields and the McCoys (1878–1891)!  Perhaps it is time for an armistice.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/25/2007 04:46 PM
So the fuel transfer is needed to bring the LSAM  up to capacity that it will have on the Ares IV?    Why is that extra performance needed?  Is it to allow longer durations on the surface, to allow for more boil off over time???
Title: Re: DIRECT v2.0
Post by: kraisee on 05/25/2007 07:11 PM
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JIS - 25/5/2007  5:26 AM
This is not that simple. You can't simply put another stage atop the rocket. LV-29 has similar payload to LEO as Jupiter claims.
I think than LV-29 use HTPB in it's SRB which allows to carry more propellants. That's the main reason why the LV-29 core + SRB is so much heavier (by 110mT) than Jupiter core + SRBs. But I still think that LV-29 is more conservative in the core weight.
Don't forget that Direct v2 study take the core weight "directly" from DIRECT v1 study without allocation any weight growth for higher stresses caused by the aditional engine.
The reason why LV-29 is minor to Jupiter is simple - higher dry mass.

Actually those are all completely incorrect assumptions.

First, the HTPB powered SRB's are lower performance than the PBAN.   The weight isn't actually that different, but the thrust is.   The reason why NASA was looking to change to HTPB was due to manufacturing issues.   PBAN is more expensive, and a little more dangerous - but it offers better performance.   When Ares-I started getting tight on performance they went back to PBAN.   We are sticking with it too.

Second, Why did you assume the Core of DIRECT v1 and v2 are the same?   The Core of DIRECT has changed considerably since v1.   The original Core only ever had two engines, and had a dry mass of 62,409kg and contained approximately 9% more propellant than STS does, with stretched LOX and LH2 tanks and had slightly heavier engines.   The current Core deliberately uses the exact same capacity as the STS ET (chosen specifically for manufacturing commonality and to address some of Dr. Stanley's issues), and the 2-engined variant has a dry mass of 61,353kg.

Just because the two designs look similar, don't confuse them as being the same.   They are not.


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This is certainly not right assuption. LV-29 carries 108mT payload (this could be anything, even another EDS) on the top. Nothing else. Jupiter-232 claims to carry up to also 108mT payload on the top. The only structural difference is caused by the maximum burnout "g" forces. For LV-29 second stage its 4g's. For Jupiter EDS its much less.

LV-29 has been designed to carry an EDS on top in order to support Lunar missions - which is the key purpose of the document.

This requirement means that the U/S of LV-29 has been designed to handle the extra weight of an EDS + payload, not just the 108mT of payload it can lift *without the EDS*.

Needing an EDS on top changes the requirements on structure masses and performance for all the stages below quite considerably.   If an upper stage massing 'x' can handle 100mT of payload during a flight, it would crumple and expire horribly if a 300mT EDS is flown on top, plus the 100mT of payload.

Further, if it has just enough power to lift 100mT of payload, it is unlikely to have enough power to lift 300mT of higher stages plus the 100mT of payload.

The U/S of the LV-29 is designed (strengthened and made more powerful) specifically to allow it to launch a heavy extra stage on top (plus cargo payload) in order to support the Lunar program requirements of an EDS/LSAM Cargo flight.


The Jupiter-232 does not have an independent Upper Stage - it has an Earth Departure Stage on top.    It it is not an Upper Stage of the Core vehicle itself in this particular context where we are comparing it to LV's from the ESAS Report.

This EDS is *not* designed to have another stage on top (plus payload).   Only payload is supposed to fly on top of this.   This means this stage is not expected to carry any additional heavy stages in addition to payload, so does not have to be "beefed-up" in the same way as LV-29's U/S has to be to handle an additional EDS.

This is why we have always said that the "concept" of Jupiter is actually closer to that of LV-24/25, and not LV-29.   Jupiter does not have an Upper Stage.   It has an EDS instead.

In these terms, you should *only* look at the Jupiter-120 as being "compatible" with LV's in the tables presented in the ESAS Report (LV-27.3 being the sole exception to the rule of course).   Like every other vehicle there, it is designed to fly a highly optimized EDS (which is not shown in those ESAS tables), but which will also boost performance during the ascent phase.

And in that frame of reference, LV-24/25 is the closest comparison to Jupiter.

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/25/2007 07:34 PM
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JIS - 25/5/2007  6:45 AM

Anyway, this comparsion is samewhat irrelevant as any NASA heavy launcher would use the same technology for EDS. Therefore, I would recommend to use pmf of 0.920 for Jupiter EDS along with J-2X spec for the next DIRECT study version. This would need additional 16klb (7.26mT) to the Jupiter EDS.
Also, you should look at the mass of the other structures.

JIS,
   Actually, we're talking behind the scenes about doing a "traditional" stage, just to remove this as an item of objection entirely.

   While *we* have confidence in the ICES, it is still unfamiliar enough with the general readership that it may, as has been demonstrated here, be considered to be a flaw rather than the optimal approach.

   As you say, we could make a stage, around 30mT, using completely traditional methods which would probably be a lot more palletable to the general audience, and just keep the ICES as another of our "upgrade" paths.

   It's not like we don't have more than sufficient spare performance to absorb such a hit and still considerably out perform Ares-I/V.

   It's something we're considering.

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/25/2007 07:41 PM
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Will - 25/5/2007  8:08 AM

I have to ask why the Centaur design philosophy isn't more popular. It isn't just Boeing: neither Ariane nor the Japanese have been able to get Centaur-like mass ratios in their upper stages. Aren't there some operational penalties and manufacturing complications from trying to get the lowest posible upper stage mass that way?

Will, the fact is that Convair were the only company pursuing the concept hard enough to make it work.   They blew up a lot of early Atlas boosters in the process of trying to learn how to manage the pressurization of the tanks on that bird.   They are the only company who didn't just "give up", so they are the only company who got it in the end.

The Centaur is fundamentally one of those Atlas boosters, converted into an Upper Stage.

It has then gone through a 40+ year long evolutionary process, which has optimized and perfected the design over and over again.   Specific technologies have been developed for specific uses of the Centaur.   Long duration propellant storage is one example, highly efficient structures are another.   You could even argue that the incredibly efficient RL-10 is part of the Centaur's long development history - and those beasties these days can produce an astonishing 470s vac. Isp!

ICES is really just the next step in this evolutionary path of the Centaur.   All the individual mission modifications which have been used on different Centaurs in the past have never been implemented together on one single stage before.   ICES is the plan to do exactly that, and to integrate all of them into one design so that they compliment each other to the maximum possible extent.

ICES isn't all that revolutionary, it is just evolutionary.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/25/2007 07:48 PM
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veedriver22 - 25/5/2007  12:46 PM

So the fuel transfer is needed to bring the LSAM  up to capacity that it will have on the Ares IV?    Why is that extra performance needed?  Is it to allow longer durations on the surface, to allow for more boil off over time???

Firstly, we aren't resolved to transferring propellant from the CEV to the LSAM.   It could be some form of inert cargo mass instead.   The trades have yet to be done to work out which is the best performance/safety/cost balance.


And it can be perfected in the early days when you fly the crew on a J-120 and the cargo on the J-232.

Once we've "found our feet" with a simpler, slightly smaller mission, the crew mission flight can be upgraded to a J-232 launcher as well and we also switch from an EOR-LOR mission profile to an LOR-LOR profile with the CEV flying on a separate EDS to the LSAM and rendezvousing occurs in Lunar orbit.

Doing that then allows the LSAM mass to be increased massively above and beyond that achievable by Ares-I/V.   We can place a 76mT (net) LSAM into 54nm LLO with the CEV, for anywhere-access.

Ares-I can not support an LOR-LOR profile at all, and there are no upgrade paths available to either Ares-I or Ares-V, so with Ares-I/V you will forever be stuck with an 39.3mT (net) LSAM in 54nm LLO with its CEV.

Ross.
Title: RE: DIRECT v2.0
Post by: clongton on 05/25/2007 08:05 PM
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kraisee - 25/5/2007  3:34 PM

 Actually, we're talking behind the scenes about doing a "traditional" stage, just to remove this as an item of objection entirely.

While *we* have confidence in the ICES, it is still unfamiliar enough with the general readership that it may, as has been demonstrated here, be considered to be a flaw rather than the optimal approach.

As you say, we could make a stage, around 30mT, using completely traditional methods which would probably be a lot more palletable to the general audience, and just keep the ICES as another of our "upgrade" paths.

Ross.
The ICES technology is not "new" technology. It has been around for a long time and all the "lessons learned" have been identified, adjudicated and incorporated. ICES works dependably well. LM has been flying this kind of stage for 40 years, longer than the Shuttle has been around. It's silly not to use this superior design in a new launch vehicle. Just plain silly. For anyone who needs more information on the ICES technology, there is a wealth of information available on publically accessable sites.

As Ross has indicated, we may offer a more traditional "standard" US "option", but make no mistake that the ICES is the preferred approach to the upper stage. It just plain offers more kg to orbit per kg of stage weight than the old-fashoned stand-by "standard" design.

We are going to be spending a lot of money to replace Shuttle and get back on track in space exploration. Let's get the best bang for the buck when we can. Let's use the best existing and flight-proven technology out there. That means ICES technology. This is no time to short-change our future. ICES is better than standard, it just is. While we can provide the option of spending our money on a less capable option, does it really make sense to do that?
Title: RE: DIRECT v2.0
Post by: kraisee on 05/25/2007 08:15 PM
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jongoff - 25/5/2007  10:44 AM

To add a little more detail to what Ross said (since I've been tangentially involved in that discussion) (SNIP)

All good points Jon, and your involvement and comments are highly valued by us.

One other factor, is that while tank mass tends to have a linear relationship to propellant volume, it is not a proportional fraction as you scale things up and down.   In the simplest terms, the larger you go, the smaller the fraction actually gets for the structure.

Purely as an example, the Centaur V1 currently used on Atlas-V masses about 1,859kg without its engine.   This can contain up to 20,799kg of LOX/LH2.   It's structural pmf is thus 0.917.

However, if you made a stage with ten times the propellant capacity, the mass of the tanking does not grow by 10 times as well.   It is a smaller fraction that that.   Now, I don't have a precise value for this example, but it's likely to be in the order of ~80% for this example.

Assuming 80% for the purposes of just a demonstration, you now have 207,990kg of propellant and a tank massing (1859*10*.8) 14,872kg - which gives your larger tank a higher pmf of 0.933.

This was factored in to the ICES figures by our sources within Lockheed.

Ross.
Title: RE: DIRECT v2.0
Post by: mars.is.wet on 05/25/2007 08:37 PM
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Jim - 25/5/2007  9:03 AM

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mars.is.wet - 24/5/2007  9:26 PM

Delta IV - 0.886 (single engine Centaur)


D-IV does not have a centaur

Ooops.  OK (single RL-10 based upper stage).  Doesn't change that fact that ESAS is the most optimistic MF U/S I can find, and DIRECT is more optimistic by 3%.  Not exactly a "slam dunk" to borrow a catch phrase.

In any case, the high mass fraction makes me worry about what other optimistic assumptions were made.  That is one thing I can say about the evolved-ESAS, it is pretty vanilla from a technology standpoint ...

Still worried about the 2 engines on the EDS.  It was a core design principle on Apollo, was a core principle pre-ESAS, and is therefore (likely from heritage) a core Constellation principle. Will take some convincing (beyond hand waving) to say that those folks missed some easy solution (like TVC) that will make the transverse loads problem go away.  Ground rules are usually there for a reason.
Title: Re: DIRECT v2.0
Post by: Will on 05/25/2007 09:16 PM
Ross writes:

"Ares-I can not support an LOR-LOR profile at all, and there are no upgrade paths available to either Ares-I or Ares-V, so with Ares-I/V you will forever be stuck with an 39.3mT (net) LSAM in 54nm LLO with its CEV. "

Upgrade paths have been quite explicitly discussed by Griffin. If propellant transfer is practical, then topping off the tanks of Ares V in LEO will allow a much greater payload to TLI, and the use of the EDS stage for LOI, allowing the LSAM to arrive in lunar orbit with the tanks full.

I'm puzzled by why you think LOR-LOR is desirable. If you launch two Jupiter 232s, you can have a rendezvous in LEO, with one carrying nothing but propellant to transfer to the EDS of the other. Since you only carry one EDS to TLI, you deliver that much more useable payload to TLI.

I agree that you should present calculations based on the same mass fraction upper stage as NASA. The key point is the tradeoffs in favor of one launcher/two launches as opposed to two launchers/1.5 launches. Using different assumptions is a distraction from the core argument.

Will
Title: RE: DIRECT v2.0
Post by: anonymous on 05/25/2007 09:47 PM
Ross, thanks very much for your detailed answers to my questions yesterday. I really appreciate it. I haven't had time to write again until now. My comments are in light of subsequent discussions.

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kraisee - 24/5/2007  8:18 PM

For the record, we have data in hand, which we can't release, which appears to *prove* that the original RS-68 Regen performance figures we used were in fact pretty close to what *is* achievable from a RS-68 with an optimized regenerative nozzle.   Our 435s figure is within 5s vac Isp of what can be done.

It's a shame that the data can't be released because if that's possible it would enable a more elegant design like DIRECT 1.0 had.

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The U/S is actually well within margins for a Centaur-derived (ICES) design.   This is a massively more efficient design, and is proven already on Atlas launchers, than the designs used by the ESAS.   Believe me, we were caught out once before, and we have been very careful not to risk that again!   Our estimates are conservative at every level.

I find your argument that you can do better with ICES convincing. It seems that the problem people are having believing it is because the payload mass fraction is higher than anything achieved before. I can see why it could be higher using ICES on a bigger stage, but to convince them it can be that high the calculations will probably have to be shown.

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Propellant Transfer.   This is routinely done on ISS - with inherently more dangerous chemicals than LOX/LH2.   Hydrazine (AKA UDMH or N2H4) and Nitrogen tetroxide (N2O4) are combustible if they just come into contact with each other.   They don't require heat, pressure or an ignition source - merely touch.   LOX/LH2 require an independant ignition source even if they are mixed together.   LOX/LH2 are tricky though, because they are cryogenic liquids.   This adds complexity, but it is nothing which can't be done if planned correctly from the start.   Thermal conditioning for the piping and valves is needed before the transfer, and launch pad-like disconnects are required when the modules are disconnected.   But cryo propellant loading can be routinely done with the correct design and procedures.

Maybe it can be made to work. You are proposing something that hasn't been done before and it's therefore the area that the proposal is actually most vulnerable.

If a technology's been successfully implemented before, you have a very strong argument that it can be used, as long as you can back up the details. I think that therefore the U/S issue is something you could make watertight if the numbers back you up.

If something's not been done before, people can always say that it can't be done for whatever reason or there's too much technical risk. That's why I think that DIRECT 2.0 is most vulnerable on this point even if you're right about everything technically. I don't see how you can prove it when it comes to cryogenic propellant transfer.

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As for 2x J-232's launching an EOR-LOR mission with no propellant transfer.   This, I have to say, has not been modelled fully, because LOR-LOR offers performance advantages if you are flying two EDS modules on two different flights.   All I can offer in this particular message are approximate answers.   Given that all I'm going to do is a "rough" work on this, here is a basic outline:-

Lift capability to 120nm circular: Cargo flight: 106.2mT, Crew flight: 105.0mT. (both plus EDS).

Additional Assumptions:
* CEV masses 20,186kg (same as Ares-I).
* EDS Burnout mass: 23,062kg
* Second EDS is unavailable for TLI on EOR profile
* No Propellant Transfer between CEV -> LSAM
* No Propellant Transfer between EDS-1 -> EDS-2
* "Rule of Thumb": TLI Using LOX/LH2 & 448s Isp, Propellant : Total Mass ratio must be 1 : 0.96 (1 ton propellant required for every 960kg of actual hardware).

So, we start with an initial breakdown:

Total lift capability (one EDS retained): 234.2mT.

Max Hardware to TLI: 114.7mT
Max Propellant for TLI: 119.5mT.   Note, this is 11.4mT more than the 232 is currently designed to carry, so without propellant transfer we immediately have to adjust these numbers down (sad waste):
-

Adjusted Total lift capability (one EDS retained): 211.8mT.

Adjusted Max Hardware to TLI: 103.7mT.
Adjusted Max Propellant for TLI: 108.1mT.

Unallocated hardware: 103.7mT - 20.2mT (CEV) = 83.5mT.

This looks pretty good to me for an LSAM Gross GLOW mass.   4mT is the harness which supports the LSAM on top of the EDS.   Effectively results in an LSAM massing about 66.2mT when it reaches LLO (LSAM performs LOI), but this would require the more risky LSAM > EDS docking in LEO (both EDS' need the harness) which we have deleted since v1.0 of DIRECT.

Thanks very much for this rough estimate - and I'm sorry about the criticism you got. I was interested because of my feeling that politically, if not technically (I'm a policy wonk, not an engineer) in-flight refuelling was your biggest vulnerability.

Since then it's become apparent that any use of EOR-LOR may well be impossible for safety reasons for an EDS with two J-2Xs. In that case, LOR-LOR would be your only option anyway.

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It's an option, but also isn't actually as safe as as an LOR-LOR profile using the same hardware.   And even that can bypass the issue of propellant transfer by transferring "safe" inert cargo from the CEV to the LSAM in LLO instead of propellant.

That's an interesting idea.
Title: Re: DIRECT v2.0
Post by: rumble on 05/25/2007 09:53 PM
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Will - 25/5/2007  4:16 PM

Upgrade paths have been quite explicitly discussed by Griffin. If propellant transfer is practical, then topping off the tanks of Ares V in LEO will allow a much greater payload to TLI, and the use of the EDS stage for LOI, allowing the LSAM to arrive in lunar orbit with the tanks full.
Yes, but you have to have something there to fill the tanks with...  Is that another Ares-V?  Ares-I certainly doesn't have margin enough to launch additional propellant.  To me, this makes it sound like the upgrade path of Ares is to go from a 1.5 launch to a 2.5 launch.

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I'm puzzled by why you think LOR-LOR is desirable. If you launch two Jupiter 232s, you can have a rendezvous in LEO, with one carrying nothing but propellant to transfer to the EDS of the other. Since you only carry one EDS to TLI, you deliver that much more useable payload to TLI.
This sounds much more practical than the "top off the Ares-V" idea

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I agree that you should present calculations based on the same mass fraction upper stage as NASA. The key point is the tradeoffs in favor of one launcher/two launches as opposed to two launchers/1.5 launches. Using different assumptions is a distraction from the core argument.
I think showing the ICES concept in there is the right thing to do, but including an ESAS EDS will remove another sticking point.  In fact, it'll lend more credence to the ICES argument by being able to say, "here's the base model [ESAS], but here's the optimized stage, and look what it does to the performance."  At that point, if people still reject Centaur technology for political or personal reasons, it'll take more than documentation to change their minds.  Personally, I'm sold on the ICES concept.

...and this "1.5 launches" nomenclature still bugs me!!  There are *two* launches with Ares I/V.  Ask the ground support crew.  Not only that, but there are two different vehicles and two sets of infrastructure!
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/25/2007 09:59 PM
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rumble - 25/5/2007  2:53 PM

...and this "1.5 launches" nomenclature still bugs me!!  There are *two* launches with Ares I/V.  Ask the ground support crew.  Not only that, but there are two different vehicles and two sets of infrastructure!
Yah, but the Ares I is only half a launch vehicle.   :bleh:
Title: RE: DIRECT v2.0
Post by: CFE on 05/25/2007 10:36 PM
It seems to me that the ICES upper stage is a major point of contention that DIRECT's detractors will latch onto.  Even if WE believe it will work, it will take a lot of convincing to get THEM to sign off on it.  I really don't have a good idea of how scalable Centaur technologies are towards an upper stage this large, but I assume that the DIRECT team has sources in ULA who have studied this concept.  These personnel may need to go public (in the form of a conference presentation, perhaps) to explain how it will all work.

Of course, Ares and Jupiter wouldn' have to quibble about upper stage mass fractions if we had better choices for first stage propulsion.

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anonymous - 25/5/2007  3:47 PM
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kraisee - 24/5/2007  8:18 PM

For the record, we have data in hand, which we can't release, which appears to *prove* that the original RS-68 Regen performance figures we used were in fact pretty close to what *is* achievable from a RS-68 with an optimized regenerative nozzle.   Our 435s figure is within 5s vac Isp of what can be done.

It's a shame that the data can't be released because if that's possible it would enable a more elegant design like DIRECT 1.0 had.

Such an engine would be a lot like the Space Transportation Main Engine study from 1988-1993.  I'd guess that if RS-68 got a new regen nozzle with a higher area ratio (~45.0,) it could bump the vacuum Isp up to from 409 sec to the 428.5 sec predicted for STME.

ESAS really worked itself into a corner by "betting the farm" on an expendable SSME that wasn't a viable solution.  We're now faced with significant architecture changes and heavier launch vehicles due to the switch to RS-68.  It may prove cheaper to design the new nozzle for RS-68 (in effect, creating a "cheap and dirty" STME) than it will to build the 10m core, redesign the MLP's, and procure the "super transporters" that will take Ares V to the launch site.  STME-like performance still falls short of SSME, but when combined with moderate reductions in LSAM mass, it will probably be good enough.

If NASA still continues to insist on an LSAM weighing over 43mT (instead of 38mT in DIRECT V2,) there's always an upgrade path available with Jupiter.  The 5-segment SRB's that NASA has always wanted can still be developed, and mated to a Jupiter 232 with stretched core.  Further performance can be gained back through the RS-68 nozzle upgrade.

It will be easier for NASA to get its foot in the door by authorizing Jupiter 120 and then upgrading to Ares V-level performance than it will to get very different rockets like Ares I and Ares V funded in an almost-sequential fashion.  That's the logic on how Congress could fund aircraft like the F-86D, F-84F, and F/A-18E.  If you sell it as an upgrade of an existing design (instead of a mostly-new design, as these were,) Congress is more likely to give you the money.
Title: Re: DIRECT v2.0
Post by: PaulL on 05/25/2007 11:26 PM
Ross, you mentionned earlier that the Jupiter 120 has a LOC of 1:1413 and a LOM of 1:234. What would be the LOC and LOM for a Jupiter 110 (simplest Jupiter launcher to put a CEV in LEO).

PaulL
Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 02:00 AM
Quote
PaulL - 25/5/2007  7:26 PM

Ross, you mentionned earlier that the Jupiter 120 has a LOC of 1:1413 and a LOM of 1:234. What would be the LOC and LOM for a Jupiter 110 (simplest Jupiter launcher to put a CEV in LEO).

PaulL

I have no idea.   The LOC/LOM numbers I am using are supplied to me from a pair of guys who worked on the ESAS Report itself.   They have all the behind-the-scenes data and methodologies which were used to calculate numbers for the other vehicles.

They offered their time to me during v1.   I try to use their skills sparingly though, because they do other important work these days.   I try not to get them to do the calculations of configurations we aren't likely to use.   J-110 was one such which I have never asked them to work up simply because it didn't fit for supporting the Lunar objectives an J-120 could do everything it could (and more) for virtually the same cost.

My guess would be that the LOC would climb slightly higher, but the LOM might actually drop because there is no longer an engine-out capability, but that's just my own personal opinion.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 02:27 AM
Quote
mars.is.wet - 25/5/2007  7:29 AM
If you had to go to a single-engine EDS, what is the performance loss?

Interestingly both Stephen and myself have been working on exactly this thing recently - switching to a single engine EDS, but with a different ascent trajectory.

Current performance of the J-232 actually has it insert into its initial 30x120nm orbit at a fairly high altitude, ~116nm, which is very near the apogee, and wastes some performance in the process.   There are sometimes performance improvements possible if you re-target for inserting at a lower altitude, closer to the perigee.   Not always, but it is something worth checking once you've done your first round of optimizations.

That analysis was not ready in time for the publication of v2.0 so we went with what we had in hand at the time.   At this time, the analysis is ongoing still, so there are no confirmed results which I will talk about yet.

Anyhow, one of the results of this new profile; it looks like by heading for a considerably lower altitude we *might* be able to achieve a similar performance (>100mT to LEO) with a single J-2X on a smaller EDS.

Such a configuration, if indeed proven, would be an excellent solution, reducing complexity and cost and solving some of the issues you have mentioned in the EOR-LOR mission profiles.

It is still very much a work in progress, much the same as NASA's Ares vehicles are continually changing.   So, watch this space.


And just a thought regarding torque loads on the docking interface between the CEV & LSAM, on the Ares EOR profile, won't the LSAM's cluster of engines performing the LOI burn potentially cause even more unbalance than the two mounted on the EDS?   Especially if any one of the LSAM's units ever fails to ignite?   Won't the interface have to be designed to survive this sort of imbalance anyway because of this failure mode?

Ross.
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 06:38 AM
Quote

And just a thought regarding torque loads on the docking interface between the CEV & LSAM, on the Ares EOR profile, won't the LSAM's cluster of engines performing the LOI burn potentially cause even more unbalance than the two mounted on the EDS?   Especially if any one of the LSAM's units ever fails to ignite?   Won't the interface have to be designed to survive this sort of imbalance anyway because of this failure mode?

Ross.

Good question.  I assume it is either the smaller moment arm or, more likely, they only use 1 for LOI, but all for ascent.    Note that the Apollo lander only had a single engine ...

Maybe if Direct went to 3 or 4 it would be OK :-)

Won't be a big deal if the design can handle the performance loss of a single engine and mass fraction reduction ...

Title: Re: DIRECT v2.0
Post by: renclod on 05/26/2007 09:37 AM
mars.is.wet
Quote
- 25/5/2007  2:29 PM
Docking rings can't take any transverse loads
Is this true ?
I know LIDS and APAS are different, but please explain "any transverse loads".

Would an bending moment  of +/-346,800 to +/-577,000 (in-lbf) qualify as transverse load ?

from 42120.ISS.APAS.ICD.pdf

Quote
SPACE STATION PROGRAM
ANDROGYNOUS PERIPHERAL ASSEMBLY SYSTEM TO PRESSURIZED MATING ADAPTER
INTERFACE CONTROL DOCUMENT
PART 1 Core (APAS to PMA-2 & 3)

TABLE 3.2.1.2.1.3-1 APAS/PMA INTERFACE LOADS (ON-ORBIT)
Case 1 Case 2 Case 3
Axial (lbf) +/-1100 +/-1100 +/-3970
Shear (lbf) +/-1100 +/-1100 +/-3310
Bending Moment (in-lbf) +/-346,800 +/-577,000 +/-346,800
Torsion (in-lbf) +/-577,000 +/-346,800 +/-346,800
Note: All loads for each case apply concurrently in any combination.
Interface loads are defined at the PMA to Orbiter APAS mechanism interface.

Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 01:51 PM
Quote
renclod - 26/5/2007  5:37 AM

I know LIDS and APAS are different, but please explain "any transverse loads".

Would an bending moment  of +/-346,800 to +/-577,000 (in-lbf) qualify as transverse load ?

from 42120.ISS.APAS.ICD.pdf


Good reference.  You are out of my element, so I don't know. I was just recalling a conversation I overheard with someone who I expect is in the know.  He did mention that it would be better if they used APAS than if they had LIDS, but both were bad.  Let's see if I can reconstruct the math.

Taking the APAS example, if J-2X has 275000 lb of thrust, an effective misalignment of 2 inches between the two engines would get you the edge of that range.  Assume EDS+LSAM is about 1000 inches (more, I think) and you get an alignment tolerance (between 2 engines) of 2/1000 = about 0.1 degrees per engine.  May also cumulatively be affected by variations in thrust (anyone know the max variation in thrust in a J-2X?).

Maybe they haven't transferred this knowledge to the LSAM yet, or maybe the factor of 5-7 reduction due to the much shorter moment arm (<200 inches) is enough to make up the difference.  Or maybe it is the fact that the LSAM engines have a fraction of the thrust (1/15th) of the J2-X and can be throttled for the LOI burn to reduce the loads.  Or maybe it is something else. But I think the ground rule for the EDS is a good one, and there are probably several others.

Also note that the ESAS EDS had 2 engines, but that it was changed shortly thereafter.  I speculate that this was one of the reasons, but I don't know.  

-------

This brings up my primary issues with putting a lot of stock in back of the envelope engineering.  It is relatively easy coming up with a design when you don't know all of the detailed constraints and ground rules (which not even ESAS had).   The problems come up in the later design phases, when the rubber hits the road and you learn of the the real-world things your particular design can't do.  Sometimes margin fixes things, sometimes it doesn't ...

That is why it is so dangerous to bag on a design that has hundreds of people contributing to it and compare it to a relatively immature design.  In my experience, once you change course, the sexy design of the day ends up looking just as bad (or worse) than the one you poured so much effort into getting out of Phase A.  Only difference is you are millions of dollars out the door and have lost a year of schedule.

It is my personal experience that it is very easy to put forth a "better" design, very hard to be right without having the team tell you all of the known gotchas, and finding your own gotchas through detailed (lots of people) design work.  Seems a bit one-sided to put forward a design that is superior on every point (I have not seen any real consideration to allow for the areas where the current architecture is superior), a design that is hundreds of thousands of hours less mature than the one you are comparing to.

As you can tell, I like armchair engineering as much as the next guy.  I just get worried when it goes from "hey this is fun" to "let's write our congress person" or "what's the next step".  Anyone who does that is likely sinking the whole program with no real chance of pushing DIRECT (or any other idea) through.  

Do YOU want a (small?) chance to go to the Moon, or do you want to do interminable design studies (which I have done) and provide more fodder for the critics to cut your budget?  When DIRECT v5.0 is accepted, and someone else proposes a radically different, "better" design a year later (which they always do) ... will you be just as gung-ho to change course to go with their proposal?   If you aren't there to defend them now ... there will be nobody there to defend you later.  By accounts, the political will on this thing is thin and a design change like this is the sort of thing that will get an Adminstrator fired, and a program cancelled.

We are rapidly passing the point of "go with the Army you got", if it is not already passed.
Title: Re: DIRECT v2.0
Post by: Jim on 05/26/2007 02:35 PM
Quote
mars.is.wet - 26/5/2007  9:51 AM
 By accounts, the political will on this thing is thin and a design change like this is the sort of thing that will get an Adminstrator fired, and a program cancelled.

This might happen anyway
Title: Re: DIRECT v2.0
Post by: Kayla on 05/26/2007 03:42 PM
Quote
mars.is.wet - 26/5/2007  8:51 AM
We are rapidly passing the point of "go with the Army you got", if it is not already passed.

When the "army" you have got was based on promises of the fastest, least expensive, most reliable solution and reality shows that it is none of these isn't it time to take heed and think of alternatives.  With Ares I at $10B and growing, under performing, late on schedule the current course is a disaster.

I agree that a lot of these alternatives don't have the foundation they need.  But when the next couple of decades of space exploration hangs in the balance maybe it is time to host an open competition (which NASA never did for Ares) and see what results.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 04:09 PM
Mars.is.Wet,
   I agree with your general comments that one design concept vs. another is a reasonable comparison, but a concept vs. a real rocket is something else.

   NASA is indeed dealing with this on the Ares-I program as it starts the long process of trying to turn the Ares-I paper concept into a real rocket.

   However, there is still a major difference between using existing hardware with a lot of real-world flight experience vs. developing all new hardware for a rocket design which has never been tried before.

   Ares-I and Ares-V are both fundamentally all-new.   They don't use standard engines, tankage or SRB's.   They can't use existing manufacturing facilities, processing equipment or launch facilities without major modifications.   Every difference adds a new layer of "beyond expectation" to the entire process, and that is where it is most difficult to predict results.

   DIRECT v2 has explicitly gone out of its way to retain everything possible from existing flight-proven hardware with flight-proven data to back it up.   Not doing so on v1 was actually a major criticism from Dr. Stanley of all people!

   The SRB's are exactly the same as the last 182 boosters used on STS.   No new nozzles, TVC, parachutes, separation systems or recovery/refurbishment changes at all.

   The RS-68's we are using are unchanged from Delta-IV, except the addition of actuators to provide additional redundancy and the likely integration of the "smaller fireball" starting systems.

   Even the External Tank is about 70% the same as the proven hardware used today on STS.   It isn't a 5.5m diameter all-new stage, and it isn't a 10m all-new stage.   We can even use *all* of the existing manufacturing equipment and procedures used at Michoud, instantly, with no fundamental changes from what we do on STS right now.

   All of these elements of the Jupiter already have qualified, proven, flight data available in the same basic configuration which we intend to use.    So there are, in practice, a lot fewer "unknowns" with these critical elements of the Jupiter LV than on either Ares-I or Ares-V.

   The "unknowns" are mostly limited on Jupiter to the new integration process - but that's nothing Ares-V isn't going to have to tackle anyway, so I see no disadvantage at all.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 04:22 PM
Quote
mars.is.wet - 26/5/2007  9:51 AM
By accounts, the political will on this thing is thin and a design change like this is the sort of thing that will get an Adminstrator fired, and a program cancelled.

The issue I have is that the Ares-I is coming in over budget and late on its intended schedule already, and we are only two years into an 8 year long process.

Are these not the factors Congress will prioritise above most others when deciding whether to fund Ares-V or not?   Is this situation not more likely than anything else to get Ares-V cancelled by Congress, irrelevant of any technical merits, good or bad?

And am I right or wrong, that if the first vehicle is the only one guaranteed, and that "political will on this thing is thin" already, that the second vehicle is going to be in serious jeopardy right through to the day it first flies or is abandoned permanently?

Isn't it a far better plan, to make damn sure that the first vehicle we build *can* enable lunar missions in case the second one is never delivered?

Ares-I alone can not enable moon or Mars missions.

Ross.
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 04:24 PM
Quote
Kayla - 26/5/2007  11:42 AM

Quote
mars.is.wet - 26/5/2007  8:51 AM
We are rapidly passing the point of "go with the Army you got", if it is not already passed.

When the "army" you have got was based on promises of the fastest, least expensive, most reliable solution and reality shows that it is none of these isn't it time to take heed and think of alternatives.  With Ares I at $10B and growing, under performing, late on schedule the current course is a disaster.

I agree that a lot of these alternatives don't have the foundation they need.  But when the next couple of decades of space exploration hangs in the balance maybe it is time to host an open competition (which NASA never did for Ares) and see what results.

How much of the slip do you attribute to the reduction in available funds?  The cool thing is that this Administrator is really willing to go as you pay.

I'm surprised you are willing to toss a bomb like 'disaster' out there, given the lack of public information on where things are.  I also wonder what the public discourse on this forum would have been like if opponents to the Apollo strategies (and there were many) selectively shared information to case their designs in a favorable light.   Would you have bailed out after the multiple technical and safety problems Apollo had early on?

how about this ... what if you put Direct up against an EELV / Ares V architecture vs. the current one ... compare cost, schedule, and risk and then iterate on those.  or maybe throw a few more in there, add a few visionary constraints and Von Braun-like "must do" statements from a person entrusted with the Vision ... have congress cut your available funds and put constrains for jobs and locations and you'll end up in a situation at least as bad as this one no matter which design you select.

I can't think of a NASA decision where the priorities were not constituency or politically driven rather than technically driven.  In my opinion, some time might be put into writing letters to Congress asking that the political procurement/management system be repealed, and that all caution for the NASA workforce be abandoned.

As much as I hate to admit it, that is the only way that the "best" technical solution MIGHT win.  And unless you concede they exist and factor those metrics into your decision process, you have little chance of providing a workable solution.

Just trying to put the thought out there that every road looks smooth on the map.  In this world of government acquisition that we are stuck with, few are.  



Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 04:38 PM
Quote
kraisee - 26/5/2007  12:22 PM

Quote
mars.is.wet - 26/5/2007  9:51 AM
By accounts, the political will on this thing is thin and a design change like this is the sort of thing that will get an Adminstrator fired, and a program cancelled.

The issue I have is that the Ares-I is coming in over budget and late on its intended schedule already, and we are only two years into an 8 year long process.

Is this fact not more likely than anything to get Ares-V cancelled by Congress, irrelevant of any technical merits, good or bad?

And am I right or wrong, that if the first vehicle is the only one guaranteed, and that "political will on this thing is thin" already, that the second vehicle is going to be in serious jeopardy.

Isn't it a far better plan, to make damn sure that the first vehicle we build *can* enable lunar missions in case the second one is never delivered?

Well, for the record, Ares-I alone can not enable moon or Mars missions.

Ross.

First issue is that "we" are 3.5 years in, not 2.  Congress does not generally give too many do-overs.   We do not have a Nunn-McCurdy breach on this one (yet).

Schedule issues are somewhat attributable to very near-term funding cuts.  Do you know how much?  If not ... do some research.

I agree that Ares V and the Moon are in trouble.  However, I'm in the camp of a slim chance being better than none.  There are no data to support one view over the other, it is just a realizationn on my part that NASA had its do-over.  It is past.  

Using the term "damn sure" indicates you have not lived through a project cancellation (or five).  By advocating changing course to a virtually unexamined (relatively) path, you are not heeding the warnings of NASA history.  By making that change you risk confirming the view that many in the U.S. have of NASA ... that they are technically wonderful but unable to follow through programmatically (X-33, X-34, X-37, X-38, SSF, ad infinitum, ad nasueum) on human and launch vehicle problems.  

In some ways, this in my view is a "last chance", and rarely do you get a chace to be 'damn sure' on those. When your mom gave you a last chance ... she rarely also gave you the benefit of the doubt two or three more times.  Again, YMMV.  That said, I would love to be "damn sure", but that time (in my opinion) has passed.

Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 04:42 PM
Quote
kraisee - 26/5/2007  12:09 PM

   The "unknowns" are mostly limited on Jupiter to the new integration process - but that's nothing Ares-V isn't going to have to tackle anyway, so I see no disadvantage at all.

Ross.

Ross, please be very careful with that sort of language.  That is EXACTLY the line under which the X-37 was sold.  An integration of existing, known technologies. (the technology items were added later ... and were somewhat immaterial to the cost grown).  You are using the very arguements that Congress may see as "the same old NASA" to cancel the program.
Title: Re: DIRECT v2.0
Post by: rumble on 05/26/2007 04:45 PM
Shuttle hardware (& infrastructure & techniques) is "the army we got."

Chase that "go with the army you got" and you end up with Jupiter 120.  Augment with an EDS and you get the Jupiter 232.
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 04:50 PM
Quote
Kayla - 26/5/2007  11:42 AM

Quote
mars.is.wet - 26/5/2007  8:51 AM
We are rapidly passing the point of "go with the Army you got", if it is not already passed.

When the "army" you have got was based on promises of the fastest, least expensive, most reliable solution and reality shows that it is none of these isn't it time to take heed and think of alternatives.  With Ares I at $10B and growing, under performing, late on schedule the current course is a disaster.

I agree that a lot of these alternatives don't have the foundation they need.  But when the next couple of decades of space exploration hangs in the balance maybe it is time to host an open competition (which NASA never did for Ares) and see what results.

How is Ares I not "most reliable" (from a LOC standpoint, which is NOT reliability)?  Do you have numbers?
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 04:57 PM
Quote
rumble - 26/5/2007  12:45 PM

Shuttle hardware (& infrastructure & techniques) is "the army we got."

Chase that "go with the army you got" and you end up with Jupiter 120.  Augment with an EDS and you get the Jupiter 232.

OK, poor analogy.  "plan you got".  Imagine an army where 1/3 the troops (to make up a number) were telling the captain how stupid he was as he chaged up the "wrong" side of the hill.  Phase A (and pre-Phase A) is for broad debate.  We are rapidly passing the point of support the plan or find a different hobby.  

This is NOT to silence the debate (which I could not do if I wanted to, which I don't).  It is simply the realities of where the team finds itself, programmatically and politically.  whether or not it is the "best" solution or plan eventually becomes irrelevant ... it is the plan.

It is not an intuitive part of reality, and it is certainly not compatible with the rigorous engineering process.  That is why the best program managers (and military leaders) are rarely engineers.  They end up overthinking the problem while the enemy overruns their position (or the program is cancelled due to apparent lack of direction).

Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/26/2007 05:01 PM
That would actually be an interesting exercise.  

Does anyone have a specific programmatic plan for changing course TO Direct from where we are today that takes into account the political realities of Griffin's departure, upcoming elections, sunk effort, negotiation with the current and next White House, workforce transition, and coalitions that have been built both with industry and Congress?

it is a necessary part of any proposed plan.

Is that someone else's job?  If so, whose?
Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 05:31 PM
Some of the outline exists, but without all the resources actually available to the 9th floor, we can only go so far on our own.

We do have some access at that level, which has come in very useful, but it is a finite resource to us.

In the broadest of strokes, the team currently producing the Ares-I U/S are switched to the EDS.   Nothing is wasted there at all.   ETA 2017.

J-2X work stays on its current course, but the budget can be stretched out a little thinner - allowing two extra years of development.   ETA 2017.

Orion work stays on target, but the team is given the option to reduce costs by using less mass-critical materials.   A number of high-cost options have had to be selected to support flights on the Ares-I which would no longer be necessary.    Additional information should be provided as early as possible  to the Orion team in order to support propellant transfer tanking options in the SM for the block-II configurations later.   ETA 2012.


MSFC/MAF/Stennis need to take it's current teams preparing the US testing of Ares-I and plan for an ET-sized stage instead.   The same people can be used and they are "up to speed" right now.   We believe we can easily get the political support of the politicial representatives in the New Orleans area to support an immediate ET-based development program instead of the Ares-I U/S switch.   ETA first hardware can start being produced immediately.

The RS-68 work being done right now for both Delta-IV and Ares-V can continue, unchanged.   But the requirement for 6% additional performance is unnecessary for the Jupiter.   This should help speed the development noticably, also reducing costs.   ETA 2012

ATK/Utah needs to be persuaded not to take the "sweetner" of developing the 5-segment booster yet.   The new sweetner is that between now and the end of 2017, they get to refurbish 208 SRB segments instead of just the 55 planned by Ares, and they are guaranteed 8 segments for every flight, instead of 5 for Ares-I and  10 only if Ares-V is ever successfully built.   ETA First new flight tests 2009, but the boosters are available today.

The "sell" can be made to the White House, Congress and the American people very easily:   We're reusing what we have to make a rocket more than twice as powerful as the Ares-I, and can do so as early as 2012, instead of 2015, and this vehicle can get us back to the moon two years early too.

That's a pretty convincing argument.   The public is accepting of "bigger rocket is better", and the politicians are normally pretty responsive to "we can do it for less cost".


The actual task of implementing these issues can equally be done by either Griffin if he wishes to remain in his current job, or by a replacement if Griffin doesn't want to be involved.   That choice isn't mine.   My personal preference would be to retain Griffin.   I'm a fan.

Ross.
Title: Re: DIRECT v2.0
Post by: clongton on 05/26/2007 06:18 PM
Quote
mars.is.wet - 26/5/2007  12:38 PM

First issue is that "we" are 3.5 years in, not 2.
Wrong. We are only 2 years in. The VSE was delivered by Bush 3.5 years ago, but Griffin has not been administrator for all that time. The current effort didn't begin until Griffin took over, +/- 2 years. Before that was Sean, and a totally different program. We are 2 years in.

Quote
Schedule issues are somewhat attributable to very near-term funding cuts.
Long before there was *any* funding cuts of any kind the schedule for the 1st Orion flight slipped from 2011 to 2012, then to 2013, then to 2014, and then to 2015. That's 4 YEARS of schedule slip caused, not by funding, but by NASA's decision to abandon the Shuttle-Derived architecture that Congress authorized. Then along came the so-called funding "cut", which wasn't a "cut" at all. NASA simply didn't get it's "raise", that's all. Congress did ***NOT*** cut funds to NASA. But this so-called cut cause an additional 6-month slip from spring 2015 to fall 2015. But guess what - that 6 month schedule slip was ALREADY in the works when the so-called "cut" happened. So even the cut caused by funding shortfalls was really caused by NASA itself. NASA abandoning the congressionally authorized Shuttle-Derived approach caused 4 years of schedule slip, while funding "cuts" caused 6 months. It's all in the record if you care to read it.

Quote
I agree that Ares V and the Moon are in trouble.  However, I'm in the camp of a slim chance being better than none.
I'm not in that camp. I am not going to sit around quietly and hope against hope that the tooth fairy will leave me a nice suprise. I would rather bet on something that can actually work, rather than a "slim" chance on something that probably won't work.   When's the last time you actually spoke to your own congressman or senator and asked about congressional support for the Mars missions? Trust me, it's slim to none. I know that because I HAVE asked. Without that committment, Ares-V isn't going to happen, and if Ares-I is all we have, it wont be you and me, it'll be your kids or grandkids trying to get us back to the moon, 30 years from now.  

Want to do something constructive? Get in touch with your representatives and senators and lobby them to increase NASA's budget. Tell them that you want a nationall committment, in the form of a law, that says NASA's budget will be 1% of GNP. You don't have to be in favor of ANY architecture, just in favor of NASA having the money it needs to get the job done.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/26/2007 06:40 PM
Quote
clongton - 26/5/2007  12:18 PM
Want to do something constructive? Get in touch with your representatives and senators and lobby them to increase NASA's budget. Tell them that you want a nationall committment, in the form of a law, that says NASA's budget will be 1% of GNP.

That would be on the order of a factor of 10 increase, and would end up representing about 5% of the entire federal budget.  That seems a bit excessive.

I'd rather see a steady, consistent rise at, say, 5% per year every single year so appropriate planning could be done and budgets could be counted upon.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 07:10 PM
Regarding budget, I would like to see last years NASA budget tied directly to the base rate of inflation and fixed for the next 20 years due to the importance of the space program as a critical national asset.

But more importantly, I would actually like to see an Administrator manage to get back most of the pork spending NASA is forced to fund.

Griffin's original plan sounded good, but I haven't seen it actually happen.   He has said that there was no way to get rid of the pork spending, which is a realistic PoV.   But he wanted the spending re-directed towards things which actually benefit the important programs with NASA rather than random spending on items which do not actually benefit NASA at all.   I would like to see an Administrator really achieve the original goal by working with the key Congress members responsible.

If only the enormous pork spending (I've heard it accounts for over $1bn of yearly budget these days) could actually be made to positively contribute to NASA programs.   It would be like a $1bn cash injection to the program and everyone would actually benefit from it.

Anyway, the discussion of changing NASA's overall budget is really outside of the scope of this thread, so can we spin this particular discussion off into a separate thread if we wish to continue it.   I'd like to keep this thread on the topic of what DIRECT can do with what is in the available budget.

Ross.
Title: Re: DIRECT v2.0
Post by: rumble on 05/26/2007 07:42 PM
I'll agree with a paraphrase of a theme I've heard a couple of times here:  Switching to "best" or "better" can sometimes cause people to lose a tremendous amount of credibility, even to the point that the better option chosen would then be subject to the "well, when is THIS one going to be abandoned also?" feelings.

Now, to apply that thought to DIRECT/Jupiter:
How could NASA change launcher architecture now without losing credibility?  It's not our intention to cause NASA to lose credibility.  We're not trying to throw Griffin overboard.  We're looking at a set of vehicles derived much more closely from existing technology, with a lower cost-to-"market," a less disruptive transition, and a quicker and less risky implementation, and I like how it looks.
To make a softer transition, instead of announcing it as tossing out what NASA's been working on for Ares, look at it as a physical scaling-back of the Ares-V, with ripple-through changes that take advantage of commonality that was impractical with a 10m core.

Try this on for size.
(begin quote) Stepping back to 4-segment boosters and an 8.4m core isn't wholely different our Ares-V in concept.  Where it does differ/benefit is from using existing tooling & scaling, and in that the infrastructure can be transitioned with far less pain.  So, if we do a minor scale-back of the Ares-V in size, we can fit much of our existing footprint.  This will yield schedule and cost benefits.
If we do that, and we're now flying with the 4-segment boosters, developing the 5-segment for only the Ares I makes less sense.  With that in mind, we're now looking at using the "newly modified/downsized" Ares V core with no EDS as a 1.5 stage crew launcher.  This will result in even more commonality in infrastructure, as well as giving us a common Ares core that shall be used on all LEO and Lunar flights, with many options in the configuration.
We're reserving the upgrade path to the 10m core for Mars missions, but for the near term, we're taking advantage of a path that looks to deliver the program we are committed to--and maybe more--while allowing us to defer some of our costs until significantly in the future.  We're making a change back to the original ESAS launch pad and VAB footprint (8.4m) for our cargo launcher, and we're taking advantage of that same reliable core in a simpler configuration for our crew launcher.
(end quote)

That has more of a "keep it in the family" feel to it.
Title: RE: DIRECT v2.0
Post by: Will on 05/26/2007 07:58 PM
Recalculating Jupiter 232 for similar mass fraction to the Ares V EDS design as of January of ’07 adds 7.26 mT to burnout mass, and reduces payload by the same amount. It should then be able to put 101 mT of net payload into LEO, plus 30mT of upper stage and residual propellant. I assume that a 4 mT payload adapter for the LSAM is not counted in net payload or in stage mass.

Devoting the entire payload of that launcher to TLI fuel would allow it to launch about 97 mT to TLI. Deducting the burnout mass of the stage and payload adapter from the total allow 63 mT of useful payload to be launched to TLI: about the same as AresV+I. That payload, in the form of a CEV and LSAM could be carried on a second Jupiter 232 with plenty of extra left over for rendezvous fuel.

This indicates the degree which the comparison between Direct v2.0 and Ares V benefits from propellant transfer and aggressive upper stage mass fraction. It also shows how much that approach suffers from manifest inefficiency: the lunar stack doesn’t divide neatly into two equal units.

The obvious solution is propellant transfer. Assuming 5 mT of rendezvous fuel, the second 232 could carry 19 mT of additional propellant, allowing almost 19 mT of additional payload to TLI. However, orbital Cryogenic propellant transfer has never been demonstrated, would add additional operational complexity, and the hardware required would eat up some of the added payload.

Alternatively, the LSAM could have an adapter between it and the payload adapter on the EDS, with two oxygen tanks attached, and attachment fittings to connect them to the EDS. This would also require some extra mass that would be deducted from useful payload.

A third alternative would be to carry the extra propellant on the LSAM, and have it complete the TLI burn. This would require extra tank capacity on the LSAM, but the dead weight of the EDS stage would not be carried all the way to TLI. I haven’t done the calculations, but suspect that useful payload would actually increase This option would require an additional start for the LSAM engines, increasing LOM.

Will


Title: Re: DIRECT v2.0
Post by: kraisee on 05/26/2007 08:08 PM
Rumble, a good approach, but I would prefer to "spin" it from the perspective of "keeping the good parts of Shuttle unchanged" rather than "scaling down Ares-V".

One sounds like we're reusing existing assets & investments to save money, the other sounds somewhat like we're pulling the "steroids" from the new Apollo ;)

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/26/2007 08:31 PM
Quote
Will - 26/5/2007  3:58 PM

Recalculating Jupiter 232 for similar mass fraction to the Ares V EDS design as of January of ’07 adds 7.26 mT to burnout mass, and reduces payload by the same amount. It should then be able to put 101 mT of net payload into LEO, plus 30mT of upper stage and residual propellant. I assume that a 4 mT payload adapter for the LSAM is not counted in net payload or in stage mass.

Basically that would indeed be the approach we would use if we switch to promoting a more "traditional" EDS ahead of the ICES in order to gain more public acceptance.

And yes, just like Ares-V's performance the 3.9mT LSAM Cradle is part of the gross payload and must be removed to get a net LSAM mass.


Quote
Devoting the entire payload of that launcher to TLI fuel would allow it to launch about 97 mT to TLI. Deducting the burnout mass of the stage and payload adapter from the total allow 63 mT of useful payload to be launched to TLI: about the same as AresV+I. That payload, in the form of a CEV and LSAM could be carried on a second Jupiter 232 with plenty of extra left over for rendezvous fuel.

This was the sort of approach we used during Direct v1 - and requires the docking of the LSAM/CEV stack to an EDS in Low Earth Orbit.   This was one of the items directly criticized by Dr. Stanley so we are trying to avoid it in this version.

Also, you 'waste' 3.9mT of raw performance because you need one of these LSAM Cradles on both the ascent flight, but then also another one on the EDS going to the moon.   We have plenty of surplus performance available, but 3.9mT is a noticeable hit.


Quote
This indicates the degree which the comparison between Direct v2.0 and Ares V benefits from propellant transfer and aggressive upper stage mass fraction. It also shows how much that approach suffers from manifest inefficiency: the lunar stack doesn’t divide neatly into two equal units.

Yes, that has been one of the key factors at the forefront of all our planning.


Quote
The obvious solution is propellant transfer.

Yup.   That's what we figured too.   And better still, Griffin's comments seem to show he believes in it also.   If it's good enough for Ares, it's sure good enough for us.


Quote
Assuming 5 mT of rendezvous fuel, the second 232 could carry 19 mT of additional propellant, allowing almost 19 mT of additional payload to TLI. However, orbital Cryogenic propellant transfer has never been demonstrated, would add additional operational complexity, and the hardware required would eat up some of the added payload.

Docking a big and heavy EDS to another big & heavy EDS using the interface between the CEV and LSAM requires that the interface between the two spacecraft must be strengthened and this adds weight.

This is one of the major factors why we favour the LOR approach.   CEV and LSAM fly separately to the moon, both EDS' are discarded and docking a CEV carrying some spare propellant is a much more achievable alternative.   The key issue is if whether we *must* enable EOR missions first, to keep NASA happier or not.   *If* we could go straight to 2-launch J-232 LOR-LOR missions, we can bypass all of these problems and also get the maximum performance right from the start of the program.

I'm starting to think this is the best approach - to start the Lunar program the way we mean to go on: 2-launch J-232 LOR from the start.

I can't see any reason why we couldn't do all the initial testing and familiarization in LEO.   It is certainly possible to use a pair of J-120's to place a CEV and LSAM into LEO to get all the practice and confidence we feel we will need later.   Actually, we could do that even before the EDS has been fully qualified - which offers potential schedule advantages.


Quote
Alternatively, the LSAM could have an adapter between it and the payload adapter on the EDS, with two oxygen tanks attached, and attachment fittings to connect them to the EDS. This would also require some extra mass that would be deducted from useful payload.

Better performance from the LSAM if the adapter is on the EDS.


Quote
A third alternative would be to carry the extra propellant on the LSAM, and have it complete the TLI burn. This would require extra tank capacity on the LSAM, but the dead weight of the EDS stage would not be carried all the way to TLI. I haven’t done the calculations, but suspect that useful payload would actually increase This option would require an additional start for the LSAM engines, increasing LOM.

That's not a good approach.   It requires that the LSAM be heavier to contain all the extra propellant, and the LSAM is the most sensitive item of all to mass increases.   Every pound of mass in the structure of the LSAM means you lose about 1.2 pounds of useful payload to the surface of the moon on every flight.

LSAM mass increases should be the very last option of all to be considered.   The CEV's low mass has already forced the LSAM to perform the LOI burn on Ares-based manned missions.   When a CEV is available, it *should* be the CEV which performs this burn.   Another option is keeping a bit of propellant in the EDS and retaining it for the LOI burn because it has higher efficiency engines.   Calculations appear to show this offers even better performance even considering the higher mass due to the EDS mass itself.   Stephen has also tried using an EDS to perform the early phase of the Lunar descent too, with good results so far.

Ross.
Title: Re: DIRECT v2.0
Post by: clongton on 05/26/2007 11:27 PM
Quote
Lee Jay - 26/5/2007  2:40 PM

Quote
clongton - 26/5/2007  12:18 PM
Want to do something constructive? Get in touch with your representatives and senators and lobby them to increase NASA's budget. Tell them that you want a nationall committment, in the form of a law, that says NASA's budget will be 1% of GNP.

That would be on the order of a factor of 10 increase, and would end up representing about 5% of the entire federal budget.  That seems a bit excessive.

I'd rather see a steady, consistent rise at, say, 5% per year every single year so appropriate planning could be done and budgets could be counted upon.
My mistake - I meant 1% of the federal budget, not gnp.
Title: Re: DIRECT v2.0
Post by: on 05/26/2007 11:52 PM

Quote
clongton - 26/5/2007  1:18 PM Long before there was *any* funding cuts of any kind the schedule for the 1st Orion flight slipped from 2011 to 2012, then to 2013, then to 2014, and then to 2015. That's 4 YEARS of schedule slip caused, not by funding, but by NASA's decision to abandon the Shuttle-Derived architecture that Congress authorized. Then along came the so-called funding "cut", which wasn't a "cut" at all. NASA simply didn't get it's "raise", that's all. Congress did ***NOT*** cut funds to NASA. But this so-called cut cause an additional 6-month slip from spring 2015 to fall 2015. But guess what - that 6 month schedule slip was ALREADY in the works when the so-called "cut" happened. So even the cut caused by funding shortfalls was really caused by NASA itself. NASA abandoning the congressionally authorized Shuttle-Derived approach caused 4 years of schedule slip, while funding "cuts" caused 6 months.

IMHO DIRECT is what Congress asked/asks Griffin for. The danger is that other budget priorities conspire to rob NASA of Shuttle and Ares V *both* - very real. From both sides of the aisle. Then the Chinese or others scare us with the Moon, and we get a costly/stupid program we race thru, attempting to play catchup with our back against the wall - a likely course. Lately the US hasn't been exactly showing its finer qualities to the world - it would be nice to not blunder here.

The political fallout is that for two years and $300M+, we've been going against the wind, having achieved little but discord. Had leadership chosen this DIRECTion, we'd have better results and more confidence instead now. Unity has a power quite valuable for our divided country right now. Especially as it shows skill and determination at renewing our space heritage with the moon that has been a key part of our national identity.  

DIRECT and CBO baseline assumptions work very well together and reinforce the picture. Its the best budgeting that can be done to reach the VSE objective,

Quote
Without that committment, Ares-V isn't going to happen, and if Ares-I is all we have, it wont be you and me, it'll be your kids or grandkids trying to get us back to the moon, 30 years from now.

Or much more. While our countrymen will never agree on everything, agreeing on some challenge would be an improvement.

Quote
Get in touch with your representatives and senators and lobby them to increase NASA's budget. Tell them that you want a nationall committment, in the form of a law, that says NASA's budget will be 1% of GNP.

Another is to explain to local political groups on both sides the long term cost of not having a rational policy for space - that holding it hostage for a false agenda cripples our nation to no ones advantage.  Then introduce budgeting and use the past "space race" as explaining what the returns are.

Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/27/2007 12:00 AM
Quote
clongton - 26/5/2007  5:27 PM

Quote
Lee Jay - 26/5/2007  2:40 PM

Quote
clongton - 26/5/2007  12:18 PM
Want to do something constructive? Get in touch with your representatives and senators and lobby them to increase NASA's budget. Tell them that you want a nationall committment, in the form of a law, that says NASA's budget will be 1% of GNP.

That would be on the order of a factor of 10 increase, and would end up representing about 5% of the entire federal budget.  That seems a bit excessive.

I'd rather see a steady, consistent rise at, say, 5% per year every single year so appropriate planning could be done and budgets could be counted upon.
My mistake - I meant 1% of the federal budget, not gnp.

Okay, so that would be $29 billion, up from $13 billion.  Still a lot to absorb.

Frankly, I'd rather see increases faster than GDP or inflation for a while, without the step-change.  If they had that, they'd know if they could afford Ares I and V or not, and if they couldn't they'd be more inclined to seek other options.

Lee Jay

Title: RE: DIRECT v2.0
Post by: Will on 05/27/2007 12:02 AM
LOR-LOR doesn’t sound like a good solution for the Jupiter 232. Jupiter 232 with a conventional upper stage mass fraction could haul the upper stage, 69 mT of propellant and 32 mT of payload to a parking orbit and then launch the payload to TLI. Two separate launches could send a total of 64 mT to TLI: considerably less than the same two launches with propellant transfer in LEO. Further, the number of mission-critical propulsion starts for TLI and LOI is doubled. Further, orbital mechanics considerably complicate rendezvous in lunar orbit: opportunities to reach a particular non equatorial lunar orbit from earth without a plane change occur only once every two weeks.

Will
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/27/2007 02:04 AM
There is one approach that I have never heard discussed,  so I imagine there are reasons that it is not considered.   Instead of LOR-LOR, why not dock before they get to lunar orbit?   The CEV/SM would carry the propellant to do the LOI burn.   That would allow the LSAM to save all of its fuel for the descent & increase is capacity pretty significantly.
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/27/2007 03:18 AM
Quote
mars.is.wet - 26/5/2007  9:51 AM

Taking the APAS example, if J-2X has 275000 lb of thrust, an effective misalignment of 2 inches between the two engines would get you the edge of that range.  Assume EDS+LSAM is about 1000 inches (more, I think) and you get an alignment tolerance (between 2 engines) of 2/1000 = about 0.1 degrees per engine.  May also cumulatively be affected by variations in thrust (anyone know the max variation in thrust in a J-2X?).

Maybe they haven't transferred this knowledge to the LSAM yet, or maybe the factor of 5-7 reduction due to the much shorter moment arm (<200 inches) is enough to make up the difference.  Or maybe it is the fact that the LSAM engines have a fraction of the thrust (1/15th) of the J2-X and can be throttled for the LOI burn to reduce the loads.  Or maybe it is something else. But I think the ground rule for the EDS is a good one, and there are probably several others.


Anybody?  From my calcs, it looks like the 2 engine loads through the docking adapter is a showstopper (thanks for the APAS specs) ... is this strong enough to change Direct to a single engine EDS?  What is the performance reduction if you combine the lower EDS PMF and using 1 engine?

Title: Re: DIRECT v2.0
Post by: kraisee on 05/27/2007 09:51 AM
Quote
mars.is.wet - 26/5/2007  11:18 PM
... is this strong enough to change Direct to a single engine EDS?  What is the performance reduction if you combine the lower EDS PMF and using 1 engine?

Mars, I haven't seen any calculations on this particular issue myself, so I won't confirm what specific remedies may be required.

But, *if* there were a switch to a single J-2XD powered EDS for any reason, the optimizations show we can still get within ~5mT of standard 2-engine performance.

If this issue does prove to be as serious as your calcs would suggest, then this might be one option path.   Better performance is still available from the full J-2X spec engine of course, but we're keeping that as a performance upgrade, not relying upon it as a critical-path item.

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/27/2007 09:56 AM
Quote
Will - 26/5/2007  8:02 PM

LOR-LOR doesn’t sound like a good solution for the Jupiter 232. Jupiter 232 with a conventional upper stage mass fraction could haul the upper stage, 69 mT of propellant and 32 mT of payload to a parking orbit and then launch the payload to TLI.


You're starting to see the precise reason why we have been looking at the ICES.   It makes the most of an extremely mass sensitive item for Lunar missions.   Every pound of EDS stage mass is basically a pound you can't use on the LSAM.   Optimizing the performance of the EDS is critical to getting the most out of any Lunar LV.

If ICES can offer a pmf between 0.92-0.93, the Lunar performance increases considerably compared to a ~0.88 pmf "conventional" stage.   This sort of difference MUST be examined very carefully indeed to get the best out of all your systems.

Rather than spend billions on getting higher performance SRB's and 6% additional RS-68 performance - neither of which are going to the moon, so aren't anywhere close to as important to optimize as reducing the mass of the EDS.

The money *should* always be prioritized for far more critical items such as the EDS, LSAM and CEV rather than on the launcher.


Quote
Further, orbital mechanics considerably complicate rendezvous in lunar orbit: opportunities to reach a particular non equatorial lunar orbit from earth without a plane change occur only once every two weeks.

That's why neither NASA nor DIRECT have ever proposed missions without budgeting for plane change manoeuvres on all missions, supporting access to all lunar locations, at virtually any time.

Just for the record, we are adhering to ESAS's dV requirements, which include the full range of plane changes required to support all foreseeable mission profiles.   Table 6-19 of the ESAS Report demonstrates the dV's we have been working with - including 510m/s for plane changes to enable anywhere access on the Lunar surface.   These numbers are conservative and can be considered "worst case".   If we support these, we can actually get better performance for most of the missions we would actually fly.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/27/2007 10:02 AM
Quote
veedriver22 - 26/5/2007  10:04 PM

There is one approach that I have never heard discussed,  so I imagine there are reasons that it is not considered.   Instead of LOR-LOR, why not dock before they get to lunar orbit?   The CEV/SM would carry the propellant to do the LOI burn.   That would allow the LSAM to save all of its fuel for the descent & increase is capacity pretty significantly.

Are you suggesting a 2-launch scenario, with two EDS' performing near simultaneous TLI burns happening so that the LSAM and CEV flown separately can rendezvous & dock after the TLI's, during the 2/3 day trip towards the moon, but before the LOI?

The logistics involved in that sort of incredible coordination scares me deeply.   Not to mention the increased dangers involved in having two space craft and two disposed-of EDS stages all in relatively close proximity to each other.   I don't think you really don't want to go there.

The only realistic options for rendezvous operations on the way to the moon are L2, L1, LLO and LEO.   I have listed these deliberately in order of best performance to worst performance.

I will say again, the Jupiters have the performance to support all of these approaches.

The Ares-I forces LEO rendezvous for all Ares missions, simply because the Ares-I is not powerful enough to ever send a CEV anywhere else.

Ross.
Title: RE: DIRECT v2.0
Post by: Will on 05/27/2007 01:55 PM
Ross writes:

"If ICES can offer a pmf between 0.92-0.93, the Lunar performance increases considerably compared to a ~0.88 pmf "conventional" stage. This sort of difference MUST be examined very carefully indeed to get the best out of all your systems."

If.

However, if you assume that you need to compare the trades against what Ares could do with the same assumptions.

Will



Title: Re: DIRECT v2.0
Post by: clongton on 05/27/2007 02:21 PM
Quote
Lee Jay - 26/5/2007  8:00 PM

Quote
clongton - 26/5/2007  5:27 PM

Quote
Lee Jay - 26/5/2007  2:40 PM

Quote
clongton - 26/5/2007  12:18 PM
Want to do something constructive? Get in touch with your representatives and senators and lobby them to increase NASA's budget. Tell them that you want a nationall committment, in the form of a law, that says NASA's budget will be 1% of GNP.

That would be on the order of a factor of 10 increase, and would end up representing about 5% of the entire federal budget.  That seems a bit excessive.

I'd rather see a steady, consistent rise at, say, 5% per year every single year so appropriate planning could be done and budgets could be counted upon.
My mistake - I meant 1% of the federal budget, not gnp.

Okay, so that would be $29 billion, up from $13 billion.  Still a lot to absorb.

Frankly, I'd rather see increases faster than GDP or inflation for a while, without the step-change.  If they had that, they'd know if they could afford Ares I and V or not, and if they couldn't they'd be more inclined to seek other options.

Lee Jay
So target 1% of the federal budget as a goal to be achieved, say in 5 years. Incrementally increase the budget, by law, from the current paultry amount to the 1% figure and thereafter hold it there as the annual funding target. Extending the human presence throughout the solar system, as the VSE calls for, needs that kind of funding committment on the part of the government.

Things have forever changed. We may not actually have it in reality yet, but for better or worse, we are becoming a space-faring civilization. Fifty to one hundred years from now spaceflight will be as nominal as air travel today. It may not be as common, because of the expense, but it will be considered normal. That appears to be one of the underlying goals of the VSE, and for that to happen *with American leadership*, requires a dependable funding stream. The only way to accomplish that is some type of congressional act which establishes a definable, dependable funding stream. NASA will still need to justify the annual budget, or lose the unjustified portion, but it will be there to move the boundaries of the VSE forward.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/27/2007 03:23 PM
Quote
kraisee - 27/5/2007  5:02 AM

Quote
veedriver22 - 26/5/2007  10:04 PM

There is one approach that I have never heard discussed,  so I imagine there are reasons that it is not considered.   Instead of LOR-LOR, why not dock before they get to lunar orbit?   The CEV/SM would carry the propellant to do the LOI burn.   That would allow the LSAM to save all of its fuel for the descent & increase is capacity pretty significantly.

Are you suggesting a 2-launch scenario, with two EDS' performing near simultaneous TLI burns happening so that the LSAM and CEV flown separately can rendezvous & dock after the TLI's, during the 2/3 day trip towards the moon, but before the LOI?

The logistics involved in that sort of incredible coordination scares me deeply.   Not to mention the increased dangers involved in having two space craft and two disposed-of EDS stages all in relatively close proximity to each other.   I don't think you really don't want to go there.

The only realistic options for rendezvous operations on the way to the moon are L2, L1, LLO and LEO.   I have listed these deliberately in order of best performance to worst performance.

I will say again, the Jupiters have the performance to support all of these approaches.

The Ares-I forces LEO rendezvous for all Ares missions, simply because the Ares-I is not powerful enough to ever send a CEV anywhere else.

Ross.

Basically what I was thinking of would be the L1 lagrange point.   I am curious about the L2 rendevous as that is first on the list by priority.   Is that true as the moons gravity helps slow down the spacecraft?   When would LOR-LOR be selected over L1-LOR or L2-LOR?
Title: RE: DIRECT v2.0
Post by: Will on 05/27/2007 03:27 PM

I don’t see performing LOI with the EDS as the most efficient approach, assuming no propellant transfer in LEO. Consider the following simplified assumptions.

Starting with 60 mT before LOI, the LSAM can perform LOI and required plane changes with 15 mT of propellant. The optimal solution from the mission mass standpoint is to use drop tanks on the LSAM. If they mass 1.5 mT, that delivers a 43.5 mT LSAM in LO, delivering 19.5 mT to the lunar surface. If the tanks are retained on the lander for operational simplicity, useful payload drops to 18 mT.

Suppose instead that the EDS performs LOI. Using the optimistic assumptions of Direct v2.0, burnout mass and payload adapter for an EDS mass about half of useful payload to TLI, so now a total mass of 90 mT must perform the maneuver, using 22.5 mT of propellant. Optimistically assuming 1.5 mT of added mass to the EDS to hold the propellant, that puts a 36 mT LSAM in LO, capable of putting only 16 mT of useful payload on the surface.

Will


Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/27/2007 03:55 PM
Quote
clongton - 27/5/2007  8:21 AM
Things have forever changed. We may not actually have it in reality yet, but for better or worse, we are becoming a space-faring civilization. Fifty to one hundred years from now spaceflight will be as nominal as air travel today. It may not be as common, because of the expense, but it will be considered normal. That appears to be one of the underlying goals of the VSE, and for that to happen *with American leadership*, requires a dependable funding stream. The only way to accomplish that is some type of congressional act which establishes a definable, dependable funding stream. NASA will still need to justify the annual budget, or lose the unjustified portion, but it will be there to move the boundaries of the VSE forward.

Space travel will *never* be as common or "nominal" as air travel is today with conventional chemical rockets.  The energy demands are too high, and the ISP is too low.  Without an order of magnitude or two improvement in ISP while maintaining the high thrust of todays systems, space travel will remain a fascinating curiosity.

Actually, this is the reason I'm not too fond of the VSE.  I don't care about designing conventional rockets and architectures that can get a few humans and their equipment to and from the Moon and Mars, I care about developing the technologies that *can* make space travel as common as air travel is today.

I actually think DIRECT is a great approach to this because it could give us a heavy-lift capacity to LEO, without the big spaceflight gap, where we could develop and test such technologies.  Being able to lift 6-10 meter diameter, 10-30 meter long, 50-150mT payloads several (many?) times per year, including the occasional group of humans, is something I see as necessary for developing, testing and proving such technologies.  Ares I has no such capability and never will.  The commercial sector is unlikely to develop such capabilities either.  This is where I think the government belongs - doing that which is necessary in the longer term, is very difficult, and is not going to get done by the commercial sector.
Title: RE: DIRECT v2.0
Post by: veedriver22 on 05/27/2007 03:57 PM
Quote
Will - 27/5/2007  10:27 AM


I don’t see performing LOI with the EDS as the most efficient approach, assuming no propellant transfer in LEO. Consider the following simplified assumptions.

Starting with 60 mT before LOI, the LSAM can perform LOI and required plane changes with 15 mT of propellant. The optimal solution from the mission mass standpoint is to use drop tanks on the LSAM. If they mass 1.5 mT, that delivers a 43.5 mT LSAM in LO, delivering 19.5 mT to the lunar surface. If the tanks are retained on the lander for operational simplicity, useful payload drops to 18 mT.

Suppose instead that the EDS performs LOI. Using the optimistic assumptions of Direct v2.0, burnout mass and payload adapter for an EDS mass about half of useful payload to TLI, so now a total mass of 90 mT must perform the maneuver, using 22.5 mT of propellant. Optimistically assuming 1.5 mT of added mass to the EDS to hold the propellant, that puts a 36 mT LSAM in LO, capable of putting only 16 mT of useful payload on the surface.

Will


I was not suggesting that the EDS would perform LOI.  With direct you could have a larger service module on the CEV.  So the CEV service module would do the LOI burn with the LSAM docked to it.
Title: Re: DIRECT v2.0
Post by: clongton on 05/27/2007 05:51 PM
Quote
Lee Jay - 27/5/2007  11:55 AM

Quote
clongton - 27/5/2007  8:21 AM
Things have forever changed. We may not actually have it in reality yet, but for better or worse, we are becoming a space-faring civilization. Fifty to one hundred years from now spaceflight will be as nominal as air travel today. It may not be as common, because of the expense, but it will be considered normal. That appears to be one of the underlying goals of the VSE, and for that to happen *with American leadership*, requires a dependable funding stream. The only way to accomplish that is some type of congressional act which establishes a definable, dependable funding stream. NASA will still need to justify the annual budget, or lose the unjustified portion, but it will be there to move the boundaries of the VSE forward.

Space travel will *never* be as common or "nominal" as air travel is today with conventional chemical rockets.  The energy demands are too high, and the ISP is too low.  Without an order of magnitude or two improvement in ISP while maintaining the high thrust of todays systems, space travel will remain a fascinating curiosity.

Actually, this is the reason I'm not too fond of the VSE.  I don't care about designing conventional rockets and architectures that can get a few humans and their equipment to and from the Moon and Mars, I care about developing the technologies that *can* make space travel as common as air travel is today.

I actually think DIRECT is a great approach to this because it could give us a heavy-lift capacity to LEO, without the big spaceflight gap, where we could develop and test such technologies.  Being able to lift 6-10 meter diameter, 10-30 meter long, 50-150mT payloads several (many?) times per year, including the occasional group of humans, is something I see as necessary for developing, testing and proving such technologies.  Ares I has no such capability and never will.  The commercial sector is unlikely to develop such capabilities either.  This is where I think the government belongs - doing that which is necessary in the longer term, is very difficult, and is not going to get done by the commercial sector.
I agree with your assessment of conventional chemical engines. I didn't go into this because it's not part of this thread, but an umderlying principle behind my statement was exactly what you imply; far better engines than what are possible today. I seriously doubt that they will bear much resemblance to todays engines. We're on the same page, and my statement about space travel being considered as "normal" as air travel today was in that context.
Title: Re: DIRECT v2.0
Post by: Stephan on 05/27/2007 06:19 PM
Hello Ross.

Will we have in a second time some figures showing (for example) acceleration vs time, dyn pressure vs time, thrust vs time etc ?
Have you studied the abort scenarios (I bet yes but I have to ask) to avoid the "black zones" as we've seen on Atlas man-rated doc recently posted here ?
It's interesting info to have for space geeks ;)

Regards
Title: Re: DIRECT v2.0
Post by: kraisee on 05/27/2007 06:35 PM
Quote
veedriver22 - 27/5/2007  11:23 AM

Basically what I was thinking of would be the L1 lagrange point.   I am curious about the L2 rendevous as that is first on the list by priority.   Is that true as the moons gravity helps slow down the spacecraft?   When would LOR-LOR be selected over L1-LOR or L2-LOR?

NASA's current management has a preference for mission profiles directly opposing performance.   Their preference order is LEO, LLO, L1, L2!

Mostly the choice is political though, not merit based.

LEO > LLO is the largest performance benefit.   L1 slightly higher, and L2 slightly more again.   Getting the decision to go to anything other than LEO is the issue.

NASA's unlikely to even give it a thought though.   Their current dictate of Ares-I as the CLV cannot support anything other than LEO rendezvous.   Everything else is impossible with their chosen LV architecture, so they don't seem to be interested in anything else at all.

Ross.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/27/2007 06:41 PM
Quote
kraisee - 27/5/2007  1:35 PM

Quote
veedriver22 - 27/5/2007  11:23 AM

Basically what I was thinking of would be the L1 lagrange point.   I am curious about the L2 rendevous as that is first on the list by priority.   Is that true as the moons gravity helps slow down the spacecraft?   When would LOR-LOR be selected over L1-LOR or L2-LOR?

NASA's current management has a preference for mission profiles directly opposing performance.   Their preference order is LEO, LLO, L1, L2!

Mostly the choice is political though, not merit based.

LEO > LLO is the largest performance benefit.   L1 slightly higher, and L2 slightly more again.   Getting the decision to go to anything other than LEO is the issue.

NASA's unlikely to even give it a thought though.   Their current dictate of Ares-I as the CLV cannot support anything other than LEO rendezvous.   Everything else is impossible with their chosen LV architecture, so they don't seem to be interested in anything else at all.

Ross.

Isn't LEO safer though ? If you have any problems elsewhere isn't there less chance of abort or rescue ?
Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/28/2007 02:59 AM
Quote
clongton - 26/5/2007  11:18 AM

Quote
mars.is.wet - 26/5/2007  12:38 PM

First issue is that "we" are 3.5 years in, not 2.
Wrong. We are only 2 years in. The VSE was delivered by Bush 3.5 years ago, but Griffin has not been administrator for all that time. The current effort didn't begin until Griffin took over, +/- 2 years. Before that was Sean, and a totally different program. We are 2 years in.

I have to agree with mars.is.wet, the NASA VSE program has been underway for 3.5 years and that is certainly how Congress views it. The rest of his comment "Congress does not generally give too many do-overs." is relevant to evaluating whether NASA can afford to return to Congress with another do-over. The first do-over was from O’Keefe’s to Griffin’s but they were both the Administration’s and Griffin was brought in specifically to “fix” the VSE implementation. That is why I agree with rumble's suggestion that Direct/Jupiter should be spun by NASA as a re-creation of Ares I/V, (perhaps as Ares II and III) rather than a new do-over.

That said I have reached the conclusion that Griffin and Horowitz are going to ride Ares I down in flames, (think Slim Pickens in Dr. Strangelove) to the detriment of their NASA careers if not their professional careers. Whether they take the VSE with them remains to be seen.

I also applaud reconsidering the EDS construction. This thread was started to elicit a form of peer review and it appears as though that review is leaning toward re-evaluation of the ICES decision.
Title: Re: DIRECT v2.0
Post by: JIS on 05/28/2007 11:42 AM
Quote
kraisee - 26/5/2007  5:22 PM

Quote
mars.is.wet - 26/5/2007  9:51 AM
By accounts, the political will on this thing is thin and a design change like this is the sort of thing that will get an Adminstrator fired, and a program cancelled.

The issue I have is that the Ares-I is coming in over budget

Any source?
Title: Re: DIRECT v2.0
Post by: JIS on 05/28/2007 12:06 PM
Quote
kraisee - 25/5/2007  8:11 PM

Quote
JIS - 25/5/2007  5:26 AM
This is not that simple. You can't simply put another stage atop the rocket. LV-29 has similar payload to LEO as Jupiter claims.
I think than LV-29 use HTPB in it's SRB which allows to carry more propellants. That's the main reason why the LV-29 core + SRB is so much heavier (by 110mT) than Jupiter core + SRBs. But I still think that LV-29 is more conservative in the core weight.
Don't forget that Direct v2 study take the core weight "directly" from DIRECT v1 study without allocation any weight growth for higher stresses caused by the aditional engine.
The reason why LV-29 is minor to Jupiter is simple - higher dry mass.

Actually those are all completely incorrect assumptions.

First, the HTPB powered SRB's are lower performance than the PBAN.   The weight isn't actually that different, but the thrust is.   The reason why NASA was looking to change to HTPB was due to manufacturing issues.   PBAN is more expensive, and a little more dangerous - but it offers better performance.   When Ares-I started getting tight on performance they went back to PBAN.   We are sticking with it too.


However, Ares V with HTPB has higher IMLEO than the same version with PBAN in SRBs. See NASA Ares V presentation.

This suggests that LV-29 (considered in ESAS study, LEO optimised) with better SRBs and higher thrust of the US should be superior to the Jupiter 232. It is not.
The reason is in either ESAS being too conservative or Direct being too optimistic (or both).
It is not only in the upper stage technology. I'm still wondering how did you estimate the Jupiter core, fairing and other structures weight. Could you give me some clue?
Title: Re: DIRECT v2.0
Post by: clongton on 05/28/2007 12:43 PM
Quote
Norm Hartnett - 27/5/2007  10:59 PM

Quote
clongton - 26/5/2007  11:18 AM

Quote
mars.is.wet - 26/5/2007  12:38 PM

First issue is that "we" are 3.5 years in, not 2.
Wrong. We are only 2 years in. The VSE was delivered by Bush 3.5 years ago, but Griffin has not been administrator for all that time. The current effort didn't begin until Griffin took over, +/- 2 years. Before that was Sean, and a totally different program. We are 2 years in.

I have to agree with mars.is.wet, the NASA VSE program has been underway for 3.5 years and that is certainly how Congress views it. The rest of his comment "Congress does not generally give too many do-overs." is relevant to evaluating whether NASA can afford to return to Congress with another do-over. The first do-over was from O’Keefe’s to Griffin’s but they were both the Administration’s and Griffin was brought in specifically to “fix” the VSE implementation. That is why I agree with rumble's suggestion that Direct/Jupiter should be spun by NASA as a re-creation of Ares I/V, (perhaps as Ares II and III) rather than a new do-over.

That said I have reached the conclusion that Griffin and Horowitz are going to ride Ares I down in flames, (think Slim Pickens in Dr. Strangelove) to the detriment of their NASA careers if not their professional careers. Whether they take the VSE with them remains to be seen.

I also applaud reconsidering the EDS construction. This thread was started to elicit a form of peer review and it appears as though that review is leaning toward re-evaluation of the ICES decision.
Not to be confused with negativity to the ICES design on the part of the Direct v2 team though. The team believes that the ICES is better than a traditional design. We are considering adding an option for the standard design, for the benefit of those who don't like the ICES, for whatever reason, in spite of over 40 years of successful operation. Our position is based on the belief (backed by research) that ICES technology on the upper stage, coupled with the J-2XD engine, will put more metric tons on a TLI than a standard design.

Aside: [We simply do not see the logic in a 40-year old rivalry between organizations, having now become nothing more than a political football with no technical merrit whatever, being the excuse to steal performance from a lunar launch vehicle.]

Having said that, if it can be shown, with the numbers, how a standard upper stage beats the ICES technology, then it will become the baseline, and ICES the option. Barring that, ICES technology is, for the time being, the baseline and the standard stage design will be the option. ICES is our preferred approach, but we are certainly not going to let it derail Direct if it can be shown that a standard design is better.

You are right. This thread was started to obtain peer review, and examination of the ICES technology is part of that. We thank those who suggest that the ICES isn't the right approach because they raised specific questions. We will do our best to answer them and provide an alternate design. Getting feedback like that is extremely helpful. We are working the specific numbers for a standard upper stage and will provide them when they are ready. And, unlike what many believe was the method used for launch vehicle selection, it won't be a stage design that is intended from the beginning to support our preferred position. It will be the best standard design we can put together. Then we will compare them. The goal is metric tons on a TLI. Whichever stage design does that best will either become or remain the baseline - by the numbers. We like the ICES technology - we really do. But we are not married to it.
Title: Re: DIRECT v2.0
Post by: braddock on 05/28/2007 01:25 PM
Quote
clongton - 28/5/2007  8:43 AM

Quote
Norm Hartnett - 27/5/2007  10:59 PM

I also applaud reconsidering the EDS construction. This thread was started to elicit a form of peer review and it appears as though that review is leaning toward re-evaluation of the ICES decision.

Not to be confused with negativity to the ICES design on the part of the Direct v2 team though. The team believes that the ICES is better than a traditional design. We are considering adding an option for the standard design, for the benefit of those who don't like the ICES, for whatever reason, in spite of over 40 years of successful operation.

I think it would be very beneficial to Direct to prove a traditional stage design option would work.  

I have no technical expertise in stage design, but I see enough numbers and concerns being posted here that imply "Direct's EDS Stage would [must?] be the best ever built".  I hope it is, but that technical ambition immediately leads to doubts, and introduces risk and controversy.
Title: Re: DIRECT v2.0
Post by: WFS on 05/28/2007 02:39 PM
What performance would a Jupiter have assuming it used the latest NASA design for an upper stage instead of the superior ICES technology used in the Direct 2.01 proposal?  

If this would be enough to complete the mission then this would help sell the concept as it would remove the red herring about whether or not the ICES stage could be built.

Also, are there planetary missions that a Jupiter 221 (Juptier 120 with an off the shelf Centaur upper stage) could perform that would not be possible with any of the current ELVs?  This could get buy in from those interested in planetary science if you can show that DIRECT will allow a wider range of missions.  
Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/28/2007 05:04 PM
Quote
clongton - 26/5/2007  11:18 AM
Not to be confused with negativity to the ICES design on the part of the Direct v2 team though.

I am not sure that most of the questioning of the ICES EDS selection represents negativity towards the design.

Direct v2 was baselined to use existing, flying hardware specifically to avoid any of the issues that arose in v1 with speculative, paper hardware. It is my understanding that no currently flying upper stage can meet the requirements of the EDS so some form of speculative hardware will needed but, as much as possible, care should be taken to extrapolate from existing flying hardware. My understanding of ICES is that it is an amalgamation of many bits of flying hardware but that they have never flown as a system. My understanding of the ESAS EDS is that it is an upsized version of existing, flying hardware. Is it possible to scale up the Centaur without adding all the hardware not currently integrated into the system?

Quote
clongton - 26/5/2007  11:18 AM
Having said that, if it can be shown, with the numbers, how a standard upper stage beats the ICES technology, then it will become the baseline, and ICES the option.
Quote
clongton - 26/5/2007  11:18 AM
The goal is metric tons on a TLI. Whichever stage design does that best will either become or remain the baseline - by the numbers.

The same was said about the inclusion of the RS-68 regenerative in Direct v1 and could be used to argue for it’s inclusion in Direct v2. My understanding of the goal of Direct v2 is to present a viable, affordable, timely option to the current Constellation program, not maximum metric tons to TLI. Now if Direct v2 can not match the ESAS goals without ICES then it must be included but if it is possible for Direct v2 to reach those parameters using a “standard” EDS then ICES should not be included. In fact it must not be included since it represents a vulnerability of the same order as the RS-68 regen.

Title: Re: DIRECT v2.0
Post by: Norm Hartnett on 05/28/2007 05:13 PM
OBTW from page 2 para 1 first sentence of DIRECT STS Derivative v2.01;

The Vision for Space Exploration (VSE) represents a watershed opportunity to expand the breath and
depth of human exploration and development for this and future generations.

breath should be breadth

Title: Re: DIRECT v2.0
Post by: Smatcha on 05/28/2007 05:46 PM
Quote
Norm Hartnett - 28/5/2007  10:13 AM

OBTW from page 2 para 1 first sentence of DIRECT STS Derivative v2.01;

The Vision for Space Exploration (VSE) represents a watershed opportunity to expand the breath and
depth of human exploration and development for this and future generations.

breath should be breadth


Spell check strikes again.  Thanks
Title: RE: DIRECT v2.0
Post by: marsavian on 05/28/2007 07:29 PM
I will repeat this post on this thread as I feel it is relevant :-

The Astronaut Office's position starts on p31 (p27 in the pdf) for those interested but definitely leans towards Ares I.

http://commerce.senate.gov/pdf/spaceflighthrg-051805.pdf

If you can get them to buy into an alternative that would be key to getting that alternative accepted as I can't see anyone in NASA or Congress going against their wishes or CAIB unless strong evidence of equivalent safety is given. The DIRECT advocates should concentrate less on performance and more on demonstrating a safer theoretical launcher than Ares I. I think an upper stage that could perhaps survive SRBs/fuel tank blowing up  or a CEV that could survive the upper stage blowing up would be avenues to explore. Use the excess weight capacity in that way in the CLV version of that launcher. You have to out-safe the Ares I not out-perform it.
Title: Re: DIRECT v2.0
Post by: clongton on 05/28/2007 07:35 PM
Quote
Norm Hartnett - 28/5/2007  1:04 PM

My understanding of the goal of Direct v2 is to present a viable, affordable, timely option to the current Constellation program, not maximum metric tons to TLI
Your understanding is partially correct.

However: One of Doug Stanley's objections was, in his opinion, Direct v1's inability to fulfill the ESAS lunar mission. That was an objection we worked hard at overcoming in v2. The proper way to do that is to optimize orbital insertion for maximum benefit to the TLI number. It is a fundamental precept for v2. Direct v2 is aimed, not at LEO, but at the Moon, Mars and beyond, and the hardware is selected with that in mind.

Step one is to replace Shuttle with a worthy successor.
Step two is to leave LEO far behind. The Jupiter launch vehicle family is optimized for deep space.
Title: Re: DIRECT v2.0
Post by: luke strawwalker on 05/28/2007 08:31 PM
Quote
marsavian - 11/5/2007  2:03 PM

Quote
zinfab - 11/5/2007  1:50 PM

Thanks for this update. I hope someone listens when it REALLY counts.

I think the Democrats will listen and if they win the Presidency they will probably install an Administrator to drop Ares I/V for DIRECT as it will allow them to beef up Science in Nasa whilst still keeping VSE going well even on a flat budget. I have reluctantly come round to Jim's way of thinking in believing that Griffin and Horowitz are so in bed with ATK they will persist with the current architecture come what may and they probably will return there to collect their rewards in 2008. This DIRECT proposal should be continued regardless to shine a light on the current architecture's failings for possible use when a different NASA power base is established.

That's what I think too.  Either the leadership at NASA is either crazy or crazy like a fox.   Personally I'm not sure which.  I think that politically whoever ends up in the Presidency next time is going to want to put as much distance between themselves and W as they possibly can, and dropping the ax on an overbudget and underperforming or at least problematic launch vehicle would be ANOTHER good way of doing that.  That is, IF the entire VSE doesn't go out the window as Bush's baby.   Fiscally the budget is doing to Ares what happened in the early 70's to the shuttle; forcing tradeoff after tradeoff of performance to attempt to reconcile with the available money and pushing the schedule farther and farther into the future.  

I just finished reading "The Space Shuttle Decision" (can't remember the author's name offhand) because I've always been perplexed WHY the original IDEA behind the shuttle and what it is and should do twisted and transformed into the dangerous money burning amalgamation of tradeoffs and compromises that it became; and that it strayed SO far from what it was originally CONCIEVED to be and do to what it EVENTUALLY turned out to be (and be capable of) that it should have occurred to people as smart as NASA's that the original idea was long lost somewhere along the way.  It was a very enlightening read and took one step by step through the political hailstorm and budgetary fallout of pursuing too high a goal with too little (and steadily dwindling) budget whilst trying to woo DOD on board to pay part of the bills while glossing over the ramifications that the necessary modifications to the design to satisfy DOD requirements would end up doing to the original idea.    Add in the grandiose visions of a Space Station, which was originally the purpose of the Shuttle and watching that idea go down in flames because of the budget; set aside for almost 15 years and then resurrected for political reasons, designed and redesigned for nearly another 15 before any hardware even flies, and now that its STILL two years from 'completion' plans are to mothball it after only another 6 years during which we'll have to bum a ride off somebody else to get to it.   I'm really starting to get a weird sense of deja vu.  

What really frightens me about the situation is that what we're seeing is the same old same old all over again.   Everybody says we need a plan, a Vision.  Just like the early 70's with the 'what do we do now after Apollo' was the 16 billion dollar question.  So, we have this broad and appealing idea to move forward that grabs interest and general support.  Now that it's time to work on the execution of that idea, the budgets dwindles repeatedly, the schedule slips again and again, and performance suffers as the design is whittled away from capabilities to absolute essentials to try to meet the fiscal realities.  Whether by intent or unconsciously, NASA chose to fly all cargo on the shuttle, essentially do away with all the ELV's probably out of the fear of its most ardent detractors talking about doing away with manned flight altogether
in the pre-Shuttle days.   What better way to prevent that than to ensure that you can't launch cargo EXCEPT on the Shuttle, which just so happens to require a crew to operate it.  (Nevermind that the Soviet Buran proved on its one and only flight that a crew wasn't necessary to operate a shuttle)   Now here we are 30 odd years later, and the argument is 'you can't fly cargo and crew on the same vehicle'.   So, we have the design of Ares I, which is so underpowered it can't even get the Orion up there without the crew taking a leak before strapping in.   Can't help but think the idea behind it is, "Well, we've GOT to have Ares V; its the cargo hauler and Ares I can't concievably do ANYTHING in orbit or anywhere else without it".  Kind of the extreme reverse of the 'launch all cargo on the manned Shuttle' concept.  

The only problem I see is, that, just like in the early 70's, the champaigne plans can't work on the beer budget, but that doesn't seem to be stopping anybody from trying.  I think (fear) what will eventually happen is that we'll get Ares I and some kind of stripped down VW Bug version of Orion to go on top of it, but it will have cost SO much and slipped SO far past it's original date that Ares V is DOA, and if anybody had really taken time to notice, had been for years.   And without Ares V Orion isn't going ANYWHERE but sightseeing trips in LEO and won't have much of anything to do when it gets there.  Just like with the Shuttle, all bets are being (mis)placed on future capabilities.  With the Shuttle it was on 'every other week flights leading to common access to space, with prices so cheap that virtually anything can (and by extension will) be flown'.   I also remember well all the pie in the sky talk of the 70's and nuclear power plants producing electricity 'too cheap to meter'.  We see how much traction that had!  Just like the original Space Station that the Shuttle was designed to serve died at the budget axeman's hands, so will Ares V.  And without Ares V we're stuck in LEO doing *nothing*.  

With any luck, the next President will drop the axe on the limp and overpriced stick but will have the wisdom to retain the 'vision' guiding space activities forward.  At that point, alternatives such as Direct II start looking awfully attractive, especially with the political ramifications of keeping the workforce intact but yet cutting costs.  Who knows, maybe even the scientific budget can even be restored after its gutting at Ares hands.  After all, science IS the reason we're exploring, right?  Otherwise we're just doing flags and footprints again aren't we?  I love manned flight, but not at the cost of the fantastic science missions and the results they've produced.   I see them as partners hand in hand in exploration.   But if things keep going in the deja vu of the 70's and STS all over again, I'm afraid we'll end up with a little bit of neither.  

Hope I'm just pessimistic.  Yall take it easy!  OL JR :)
Title: Re: DIRECT v2.0
Post by: aftercolumbia on 05/28/2007 09:04 PM
I haven't had the ability to sort this thread out, but I have read the report and found some disappointments:

- everything regarding the VAB and MLP modifications has gone AWOL.  I though those were some of the strongest arguments in favour of Direct in the original report.
- It is very short for such an important topic.

I think there are some additional variants that should work quite nicely:
- Jupiter 231: Same upper stage tanks and engine type, single engine.  This would be excellent for big high energy unmanned missions, such as robotic sample return missions and outer solar system orbiters (i.e. Uranus and Neptune).
- Jupiter 226: Uses six engine version of Centaur VI (i.e. Atlas VI, or what LM is calling "Phase 1 Evolution") with six times the current Centaur propellant load as a 3rd stage.  This would be analogous to the Saturn I.
- Jupiter 230: This configuration is mentioned, but not named in the report as "upper stage tank/boil-off test - No J-2X engines"  Obviously, the upper stage would need to be launched with a considerable off-load to make orbit, and the resulting launch would be just as much a test of the control system and interstage to handle the sloshing of its propellants.
- Jupiter 236: Just thought of it now, launching the upper stage without a payload, but with 6 RL10A-4 engines to complete ascent.  After achieving orbit, one of the experiments that could be done with it is a sunshine LOX vaporization to reduce the NPSH of both propellants to as low a value as one can light the engines with.  This could be used to detect any line cavitation such as Delta IV suffered.  It could also expand the flight qualified NPSH range of the RL10A-4 and RL10B-2 (if its machinery is close enough for QBS.)  I'm also pretty sure that Pratt & Whitney would love to be able to test six of their engines with a huge reserve of propellant to play around with in an experimental orbital environment where we really don't care if it blows up.
- Jupiter III: Teamvision has this huge mean looking mother which straps two stock Shuttle ETs onto an enormous core and two stock (4 segment) SRBs onto each of the Shuttle ETs (total 4 SRBs).  The ETs feed approximately seven RS-68s under the core.  This is the first known serious NOVA class SDV (some Orbiteers tinkered with big clusters of strapped ETs.  The one I tried had so much thrust and so little pitch control moment that I couldn't pitch it over properly, defaulting to a Juno I type ascent profile...the common feature of each is that they are ugly, mean looking beasts...the sort of ugly that would make Emperor Palpatine drool.)
Title: Re: DIRECT v2.0
Post by: marsavian on 05/28/2007 09:06 PM
Luke,

Actually the more I read and learn on the subject it's more like ATK are in bed with Griffin and Horowitz ;-). I do believe now that what drives them ultimately is conviction on their chosen architecture. I think that Ares V will eventually turn up regardless of who is in power but given the Democrats generally less enthusiastic willingness to spend money on Space you could be looking at a Moon mission more closer to 2025 than 2020. If that's ok with everyone ...
Title: Re: DIRECT v2.0
Post by: kraisee on 05/29/2007 03:59 AM
Just to de-rail the argument about how far into the process we are right now, my earlier comment was:

Quote
kraisee - 26/5/2007  12:22 PM

The issue I have is that the Ares-I is coming in over budget and late on its intended schedule already, and we are only two years into an 8 year long process.

Note that the reference point was "Ares-I", not "VSE".   Ares-I didn't start development until the ESAS Report chose it, more that a year and a half after the VSE was announced.

The ESAS Report was not released until November 2005.

So to completely clarify, I will reissue my original comment.   It should have been:

"The issue I have is that the Ares-I is coming in over budget and late on its intended schedule already, and we are only 1.5 years into what is currently planned to be an 8 year long development process for this launcher."

If I had been referring to the "VSE", my timeline would actually have been 3.5 years into a 16 year long process (Jan 2004 > Jun 2019's first lunar landing).

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/29/2007 04:15 AM
Quote
Will - 27/5/2007  11:27 AM


I don’t see performing LOI with the EDS as the most efficient approach, assuming no propellant transfer in LEO. (SNIP)

Let me make sure this isn't misunderstood: It is something we are investigating, but not something we are baselining.

As our proposal shows on page 9, all our initial plans do not use the EDS for the LOI for either EOR or LOR profiles.   Page 10 shows the LOI burn being performed by the EDS as an "Option" which can be considered for "Enhanced" missions later.

One of our team has been doing some analysis work of different approaches using Copernicus, one of NASA's tools for just this sort of job.

We have been getting good results from early test of a number of non-traditional approaches including this.   Actually we are getting sufficiently good results that we thought it was worth including in our proposal.   This was mainly to introduce the concept so we could get others, outside of our team, to go investigate it themselves and see the same benefits.

EDS LOI certainly isn't hard-wired by any means into the DIRECT plan.   It is something to be investigated in case it does offer performance benefits.

Thinking "outside of the box" was Houbolts gift to NASA in the 60's.   Because we've become a bit of a "rebel" team, we seem to have drawn quite a number of individuals who have also come up with ideas that don't fit in the "traditional" moulds.   Some of these ideas, when run through a real analysis, sure seem worth investigating further instead of just dismissing.

These ideas are certainly not all going to be successful in the end.   But some of them are surprisingly simple to implement, and are proving to be very effective according to the early analysis we've done.

If they were to fully proven, they might offer considerable benefits.   So we're spending time looking at them more deeply to get the best possible results out of the VSE's investments we can.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/29/2007 04:39 AM
Quote
SMetch - 28/5/2007  1:46 PM
breath should be breadth


Spell check strikes again.  Thanks[/QUOTE]

I had that fixed for v2.0 of the doc, but it looks like it managed to sneak back in again.   I think we suffered from one of the problems of collaboration across the internet :)

Its fixed now.

Ross.
Title: RE: DIRECT v2.0
Post by: kraisee on 05/29/2007 05:06 AM
Quote
marsavian - 28/5/2007  3:29 PM

I will repeat this post on this thread as I feel it is relevant :-

The Astronaut Office's position starts on p31 (p27 in the pdf) for those interested but definitely leans towards Ares I.

http://commerce.senate.gov/pdf/spaceflighthrg-051805.pdf

If you can get them to buy into an alternative that would be key to getting that alternative accepted as I can't see anyone in NASA or Congress going against their wishes or CAIB unless strong evidence of equivalent safety is given. The DIRECT advocates should concentrate less on performance and more on demonstrating a safer theoretical launcher than Ares I. I think an upper stage that could perhaps survive SRBs/fuel tank blowing up  or a CEV that could survive the upper stage blowing up would be avenues to explore. Use the excess weight capacity in that way in the CLV version of that launcher. You have to out-safe the Ares I not out-perform it.

We really need an "in" within the astronaut corps.   Just sending the proposal to individual astronauts isn't likely to do anything useful.   We tried it during v1 and didn't get much in the way of a response.   I'm not even sure the proposals were ever read.

But I can well imagine that the idea of placing a 20 ton "shield" between your butt and a rocket filled with highly explosive fuel below, might gain some attention every single person deliberately putting themselves in that position.

The issue is how to get that simple message to the right people, and getting them thinking about it.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/29/2007 05:14 AM
Quote
luke strawwalker - 28/5/2007  4:31 PM

I just finished reading "The Space Shuttle Decision" (can't remember the author's name offhand)

That would be Thomas A. Heppenheimer.

The whole document is available on NASA's History site here: http://history.nasa.gov/SP-4221/contents.htm


Anyone here who hasn't read it should take a few hours and go do so.

The similarities between the current decision making process and the one which resulted in Shuttle are shocking.   The process it describes has been directly responsible for killing 14 people already and should have been a prominent feature in the CAIB findings.   Sadly, it seems to have been overlooked though.

"Those who cannot learn from history are doomed to repeat it" -George Santayana

I can't help but feel that Ares-I falls into this immediate category.

Ross.
Title: Re: DIRECT v2.0
Post by: CFE on 05/29/2007 05:35 AM
The difference between Ares I and Shuttle is that Ares I is not breaking any new technological ground.  The shuttle was clearly a bridge too far, based on our inexperience with winged reentry vehicles and reusable spacecraft.

At the same time, I hear echoes of the broken promises of the shuttle program in discussions of Ares I.  The shuttle was supposed to "replace all launch vehicles except the very biggest & very smallest," fly every two weeks, possess a LOC rate better than 1:2000, and bring launch costs down by an order of magnitude.  None of that came to pass.  Now NASA is telling us that Ares I will be "Safe, Simple & Soon."  

Ares I may be fairly safe, but it now requires an extra burn of the SM engine and all the added risk that entails.  It also treats the 5-segment SRB as safe despite the booster's lack of flight history.  It's simpler now that "expendible SSME" has been dropped, but no launch vehicle is truly simple.  And we can clearly say that Ares I won't be soon; the spaceflight gap is at five years and counting.  If it reaches six years, it will be worse than the gap between ASTP & STS-1.

The truth is that Ares I is "maybe safe, maybe simple."  DIRECT should bill itself as "Safe Enough and Soon."
Title: Re: DIRECT v2.0
Post by: kraisee on 05/29/2007 07:01 AM
Quote
Norm Hartnett - 28/5/2007  1:04 PM
Is it possible to scale up the Centaur without adding all the hardware not currently integrated into the system?

Yes.   Fundamentally any source could be used for the EDS.

The EDS for Ares-V though is currently not borrowing from any non-MSFC source.   Like Ares-I, they are designing it themselves completely independently, from scratch - without input (at this point anyway) from the Centaur program.

The Centaur team is not likely to be invited to get involved in the Ares-V's EDS until such time as a contract is actually issued - and then only if that team actually wins the contract.   I wouldn't expect that decision for at least another five years, at the earliest.

We have a pure Centaur-derived EDS concept here, just with a J-2XD on it, not any breed of RL-10, suitable for a theoretical "Jupiter-231".   It masses 19.3mT and matches the existing proven Centaur's pmf value.   Using this J-231 we can still easily match and exceed lunar performance of Ares-I/V on an EOR profile - but we would require propellant transfer to use it.

Lunar performance is still definitely best using a pair of 232's and an Lunar Rendezvous approach (which remove the issue with CEV/LSAM docking hatch torque loads of the two-engine configuration).

Actually, there is a technique we are investigating currently which would potentially neutralize the two-engine torque loads completely.   One of our team has a possible solution and we are working out the full implications before announcing it.

Ross.
Title: RE: DIRECT v2.0
Post by: marsavian on 05/29/2007 08:29 AM
Quote
kraisee - 28/5/2007  12:06 AM

Quote
marsavian - 28/5/2007  3:29 PM

I will repeat this post on this thread as I feel it is relevant :-

The Astronaut Office's position starts on p31 (p27 in the pdf) for those interested but definitely leans towards Ares I.

http://commerce.senate.gov/pdf/spaceflighthrg-051805.pdf

If you can get them to buy into an alternative that would be key to getting that alternative accepted as I can't see anyone in NASA or Congress going against their wishes or CAIB unless strong evidence of equivalent safety is given. The DIRECT advocates should concentrate less on performance and more on demonstrating a safer theoretical launcher than Ares I. I think an upper stage that could perhaps survive SRBs/fuel tank blowing up  or a CEV that could survive the upper stage blowing up would be avenues to explore. Use the excess weight capacity in that way in the CLV version of that launcher. You have to out-safe the Ares I not out-perform it.

We really need an "in" within the astronaut corps.   Just sending the proposal to individual astronauts isn't likely to do anything useful.   We tried it during v1 and didn't get much in the way of a response.   I'm not even sure the proposals were ever read.

But I can well imagine that the idea of placing a 20 ton "shield" between your butt and a rocket filled with highly explosive fuel below, might gain some attention every single person deliberately putting themselves in that position.

The issue is how to get that simple message to the right people, and getting them thinking about it.

Ross.

Yeah, now that's the way to sell it ! Your No.1 priority must be to to beat the 1~2000 LOC figure Ares I has got and even Horowitz might be swayed ;-). Although funnily enough NASA don't seem to mind putting Astronauts on a Ares V which does smack of double standards ;-).

A couple more questions, you have not changed the price differences between Direct and Ares despite all the economic counter arguments Dr Stanley gave, did you not believe any of them ? The second question I have is I'm not quite clear how you can deliver the same mass LSAM with a Jupiter 232 compared to an Ares V given the odd 30mT difference in lift capability ?
Title: RE: DIRECT v2.0
Post by: clongton on 05/29/2007 11:44 AM
Quote
kraisee - 29/5/2007  1:06 AM

We really need an "in" within the astronaut corps.
John Young?
Title: Re: DIRECT v2.0
Post by: luke strawwalker on 05/29/2007 02:56 PM
Thanks!  I'm working on "This New Ocean" by Burrows at the moment, when I'm not trying to catch up on the Direct II thread:)  Have a good one!  OL JR :)
Title: RE: DIRECT v2.0
Post by: anonymous.space on 05/29/2007 07:20 PM

In addition to John Young, the advocates of DIRECT 2 might also contact Dr. Paul Spudis at APL.  He gave a presentation at ISDC criticizing Ares, and he most favors a "Shuttle-C" type approach.

Here's a thread I started on Spudis's comments, with links to the article and his presentation:

http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=8102&posts=2#M140822

i don't know if he's aware of DIRECT 2, but Spudis appears to be a kindred spirit with some decent name recognition.

FWIW...
Title: Re: DIRECT v2.0
Post by: Smatcha on 05/29/2007 08:05 PM
Quote
Norm Hartnett - 27/5/2007  7:59 PM

Quote
clongton - 26/5/2007  11:18 AM

Quote
mars.is.wet - 26/5/2007  12:38 PM

First issue is that "we" are 3.5 years in, not 2.
Wrong. We are only 2 years in. The VSE was delivered by Bush 3.5 years ago, but Griffin has not been administrator for all that time. The current effort didn't begin until Griffin took over, +/- 2 years. Before that was Sean, and a totally different program. We are 2 years in.

I have to agree with mars.is.wet, the NASA VSE program has been underway for 3.5 years and that is certainly how Congress views it. The rest of his comment "Congress does not generally give too many do-overs." is relevant to evaluating whether NASA can afford to return to Congress with another do-over. The first do-over was from O’Keefe’s to Griffin’s but they were both the Administration’s and Griffin was brought in specifically to “fix” the VSE implementation. That is why I agree with rumble's suggestion that Direct/Jupiter should be spun by NASA as a re-creation of Ares I/V, (perhaps as Ares II and III) rather than a new do-over.

That said I have reached the conclusion that Griffin and Horowitz are going to ride Ares I down in flames, (think Slim Pickens in Dr. Strangelove) to the detriment of their NASA careers if not their professional careers. Whether they take the VSE with them remains to be seen.

I also applaud reconsidering the EDS construction. This thread was started to elicit a form of peer review and it appears as though that review is leaning toward re-evaluation of the ICES decision.

LOL :)



Title: RE: DIRECT v2.0
Post by: kraisee on 05/30/2007 12:48 AM
Quote
marsavian - 29/5/2007  4:29 AM

Yeah, now that's the way to sell it ! Your No.1 priority must be to to beat the 1~2000 LOC figure Ares I has got and even Horowitz might be swayed ;-)

Well, for a Jupiter-120 flight, carrying a 20 ton ballistic shield, I've heard estimates of from doubling to quadrupling the safety for Crew.

In the absence of any available analytical method to evaluate such a "bullet proof vest" approach for actively protecting the CEV during catestrophic LV loss scenario's, a simple doubling or quadrupling of NASA's LOC figure generates 1:2,800 or 1:5,600 LOC.

I've asked my ESAS sources to generate a full evaluation, but this has simply never been done before on any launch vehicle, so they aren't sure how to assign it a value.   They certainly feel that it offers a very high level of protection for crews, but have no baseline to reference a 'number' from.

Of course, the LOM stays roughly where it is.   Mind you, even it isn't bad at all.


Quote
Although funnily enough NASA don't seem to mind putting Astronauts on a Ares V which does smack of double standards ;-).

Yeah.   I always found that hypocritical.   Especially as the LOC for Ares-V is below the "minimum" of 1:1000 LOC set by the ESAS.


Quote
A couple more questions, you have not changed the price differences between Direct and Ares despite all the economic counter arguments Dr Stanley gave, did you not believe any of them ?

We have an addendum to our core study coming soon dealing with that.


Quote
The second question I have is I'm not quite clear how you can deliver the same mass LSAM with a Jupiter 232 compared to an Ares V given the odd 30mT difference in lift capability ?

We are bringing only some of the LSAM's final mass up on the J-232, and the rest up with the Crew on the other flight.

Because the CEV masses only 20.2mT, and we have at least 46 tons of lift capability on even the smallest Jupiter-120, this allows about 20 extra tons to be brought up and then transferred to the LSAM in space.

This additional mass might be in the form of cargo or propellant, but when transferred, it makes an LSAM massing at least the same as Ares'.

Where the plan really benefits is in flying an EDS on the Crew flight as well - at which point the exact same technique creates an LSAM far bigger than anything Ares-I/V can ever hope to lift.

In short, for the "price" of learning new procedures of how to transfer mass (cargo or propellant) from the CEV to the LSAM in space, you can get a Lunar Lander about 40-50% larger than currently planned, and do so while paying for only one shiny new LV instead of two.

Ross.
Title: RE: DIRECT v2.0
Post by: marsavian on 05/30/2007 10:58 AM
Ross,

Thanks for your answers. It does seem to me though that you are not taking account of the first part of your answer in the last part. If you use part or all of the 120's excess capacity as a ballistic shield then you can't use it to carry useful payload too. To me this implies that there should be no 120 only a 130 and a 231/2. This way you can still keep only one base launcher, have 10-20T of solid steel directly under the CEV and still have capacity to carry extra payload in the 130 underneath the shield. You said before the 130 wouldn't work, is that with a maximum theoretical payload ? Is a stretch of the tank such a no-no ? Of course the 231 wouldn't need the ballistic shield with just cargo flying. You really need to get your guys working the numbers, doing blast calculations and come up with a more rounded proposal which isn't just concentrating on performance and cost. Your deadline is 2008 when a new administrator takes over.
Title: RE: DIRECT v2.0
Post by: mars.is.wet on 05/30/2007 01:53 PM
Quote
marsavian - 30/5/2007  6:58 AM
 Your deadline is 2008 when a new administrator takes over.

Election is in 2008, president takes over in 2009, ... TBD how long (and if person is otherwise occupied or distracted IF) they replace the current Administrator.  NASA would certainly not be "first to fire" on anyone's list in THIS race, and NASA may not be on the radar for some candidates.

I imagine it could be mid-to-late 2009, but what do I know?  IMO this architecture will be well established before there is any change, if any occurs.

Anyone think Griffin would resign?  


Title: RE: DIRECT v2.0
Post by: William Barton on 05/30/2007 02:04 PM
Quote
mars.is.wet - 30/5/2007  9:53 AM

Quote
marsavian - 30/5/2007  6:58 AM
 Your deadline is 2008 when a new administrator takes over.

Election is in 2008, president takes over in 2009, ... TBD how long (and if person is otherwise occupied or distracted IF) they replace the current Administrator.  NASA would certainly not be "first to fire" on anyone's list in THIS race, and NASA may not be on the radar for some candidates.

I imagine it could be mid-to-late 2009, but what do I know?  IMO this architecture will be well established before there is any change, if any occurs.

Anyone think Griffin would resign?  



I don't have a link or reference, but it's my recollection Griffin has said he doesn't intend to continue in office beyond the end of the current administration.
Title: RE: DIRECT v2.0
Post by: mars.is.wet on 05/30/2007 04:22 PM
Quote
William Barton - 30/5/2007  10:04 AM

Quote
mars.is.wet - 30/5/2007  9:53 AM

Quote
marsavian - 30/5/2007  6:58 AM
 Your deadline is 2008 when a new administrator takes over.

Election is in 2008, president takes over in 2009, ... TBD how long (and if person is otherwise occupied or distracted IF) they replace the current Administrator.  NASA would certainly not be "first to fire" on anyone's list in THIS race, and NASA may not be on the radar for some candidates.

I imagine it could be mid-to-late 2009, but what do I know?  IMO this architecture will be well established before there is any change, if any occurs.

Anyone think Griffin would resign?  



I don't have a link or reference, but it's my recollection Griffin has said he doesn't intend to continue in office beyond the end of the current administration.

May be the theory is like this.  If the new person likes space, and Griffin is doing a good job, they will put their own person in to take the credit.  If the new person likes space and Griffin is doing a "bad" job, he will be replaced on merit.  If the new person doesn't care about space or the Moon in specific, then Griffin would not want to work there.  In any case, it requires the person to evaluate NASA and the job Griffin is doing (and Griffin to evaluate their position) before any move is made.  This takes time ... Griffin never said he would leave if the Vision were alive ... he just said he didn't think he would at NASA.

My thought would be the new person sees that Griffin has made progress and is the right person for the job.  They don't think space is a huge priority, but even the lesser children need guidance.  Griffin would be allowed to stay to keep the ship on course until NASA rises in priority due to success or mis-management.

In any case, mid-2009 is the earliest one could hope for, if one hopes for these sorts of things.  The president changes the curtains in the oval office first, then the cabinet, then a bunch of other things ... he or she does not start with the head of NASA unless they are a space-nut.  Sometimes (see Dan Goldin), it matters so little to them that the person in place stays put ....

Title: RE: DIRECT v2.0
Post by: kraisee on 05/30/2007 04:38 PM
Quote
marsavian - 30/5/2007  6:58 AM

Ross,

Thanks for your answers. It does seem to me though that you are not taking account of the first part of your answer in the last part. If you use part or all of the 120's excess capacity as a ballistic shield then you can't use it to carry useful payload too.

It's a concious choice.   For simple crew rotation flights to ISS, where no additional performance is needed, the shield can be flown to provide maximum crew safety.   But for Lunar missions, where performance is a major factor, the shield is not flown and the payload is used for some other purpose.


Quote
To me this implies that there should be no 120 only a 130 and a 231/2. This way you can still keep only one base launcher, have 10-20T of solid steel directly under the CEV and still have capacity to carry extra payload in the 130 underneath the shield. You said before the 130 wouldn't work, is that with a maximum theoretical payload ? Is a stretch of the tank such a no-no ? Of course the 231 wouldn't need the ballistic shield with just cargo flying. You really need to get your guys working the numbers, doing blast calculations and come up with a more rounded proposal which isn't just concentrating on performance and cost. Your deadline is 2008 when a new administrator takes over.

A J-130 configuration (single cryo stage, 3xRS-68's) doesn't work so well.   Unless you shut down one of the engines fairly early in the flight you haven't got sufficient fuel to reach orbit in the ET.   And if you shut down one engine, you're dragging a dead engine along for most of the ride - and that doesn't assist your payload performance at all.   The J-120 outperforms the J-130 in any flight profile we can come up with.   In short, the 3-engine version needs an upper stage to work.

Our team of ~50 people have limited resources, so we're using them sparingly.   I'm not even sure if there is a way to test all the various ways a vehicle can explode.   Certain known critical failure modes can be simulated - and we have a number of such analysis in hand already courtesy of STS.

The biggest improvement which can be provided is the LAS - and that's already included.   The ballistic shield concept is something we can make use of, which Ares-I can't, and do so in many situations, but still probably not all.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 04:48 PM
Griffin originally said (paraphrasing) he expected to stay as long as the current political masters were in office, but expected to leave when it was eventually replaced.   But he has also, more recently, said that he would like to stay longer if he were asked to.

Either way, I'm sure he can get a damn good pay check in the private sector whenever he does leave.   O'Keefe did.

From my perspective though, I think Ares-I will prove to be the first major make-or-break artefact in the new program.   It's success/failure will specifically dictate the shape of what's to come.

The more I hear about it internally from people actually working the development, and the more I see the shadow of Congress looming over the program, the lower my hopes dwindle for any chance of success.   For the first time, I now believe the VSE is below 50/50 chance of ever being completed, and the biggest chain dragging us down is the Ares-I.

Ross.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/30/2007 04:52 PM
If the purpose of the shield is to provide very short-term protection from flying debris, why does it have to weigh 20 tons?  A 2cm-thick, 5m-diameter piece of Boron Carbide armor would weigh 1 ton (it's one of the materials used in the ceramic plates soldiers use to stop rifle bullets).  I don't really know much about the stuff, but it's a ceramic with a high melting point (> 2300°C), and so should provide at least some short-term thermal protection as well.
Title: Re: DIRECT v2.0
Post by: clongton on 05/30/2007 05:01 PM
Quote
Lee Jay - 30/5/2007  12:52 PM

If the purpose of the shield is to provide very short-term protection from flying debris, why does it have to weigh 20 tons?  A 2cm-thick, 5m-diameter piece of Boron Carbide armor would weigh 1 ton (it's one of the materials used in the ceramic plates soldiers use to stop rifle bullets).  I don't really know much about the stuff, but it's a ceramic with a high melting point (> 2300°C), and so should provide at least some short-term thermal protection as well.
Hmmm. With those properties, and Jupiter's margin, it could almost be included as a standard feature in the design, and still leave the vast majority of the margin available for other purposes. Time to go run some numbers.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/30/2007 05:10 PM
Quote
clongton - 30/5/2007  11:01 AM

Quote
Lee Jay - 30/5/2007  12:52 PM

If the purpose of the shield is to provide very short-term protection from flying debris, why does it have to weigh 20 tons?  A 2cm-thick, 5m-diameter piece of Boron Carbide armor would weigh 1 ton (it's one of the materials used in the ceramic plates soldiers use to stop rifle bullets).  I don't really know much about the stuff, but it's a ceramic with a high melting point (> 2300°C), and so should provide at least some short-term thermal protection as well.
Hmmm. With those properties, and Jupiter's margin, it could almost be included as a standard feature in the design, and still leave the vast majority of the margin available for other purposes. Time to go run some numbers.

Please take note of where I said, "I don't really know much about the stuff".  I've read about it a bit and I did a quick back-of-the-envelope calculation on mass.  I don't know if it makes sense as a shield or not, but 20 tons strikes me as 1/3 the mass of an M1A1 which is surrounded by huge amounts of Chobham armour - way heavier stuff.

Lee Jay
Title: Re: DIRECT v2.0
Post by: mars.is.wet on 05/30/2007 05:10 PM
"ever being completed"

I agree if you refer to the current incarnation of VSE.  However, Griffin's "next 50 years" article makes it pretty clear that if human space flight remains any sort of priority, the budget will be enough that we won't be able to help but make it to the Moon and Mars within the next few generations.  If NASA's budget is cut or reprioritized (global warming?), all bets are off.

Depends on your time horizon.
Title: RE: DIRECT v2.0
Post by: marsavian on 05/30/2007 05:10 PM
Ross,

Not having a ballistic shield every time you fly a crew and by inference a higher LOC figure than Ares I will be a weakness that your opponents will use against you. ISS configuration is a sideshow here compared to the Moon and Mars and is irrelevant in the long term. If there isn't enough fuel for a Jupiter 130 stretch the 8.4m tank until you do have enough. Work harder on your weaknesses than your strengths. It's your choice of course but you really need to beat the current architecture on *all* points otherwise it will just be continued to be ignored.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 05/30/2007 05:13 PM
Quote
Lee Jay - 30/5/2007  9:52 AM

If the purpose of the shield is to provide very short-term protection from flying debris, why does it have to weigh 20 tons?  A 2cm-thick, 5m-diameter piece of Boron Carbide armor would weigh 1 ton (it's one of the materials used in the ceramic plates soldiers use to stop rifle bullets).  I don't really know much about the stuff, but it's a ceramic with a high melting point (> 2300°C), and so should provide at least some short-term thermal protection as well.

The primary purpose of the "shield" is to provide 20 tons of ballast in addition to the 25 ton CEV, because the rocket needs the 40+ tons of payload in order to stay within its designed trajectory and g-loading envelope.  The crew protection is just a desirable side-effect.

An actual shield does sound like an interesting idea, though.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/30/2007 05:17 PM
Quote
SolarPowered - 30/5/2007  11:13 AM

Quote
Lee Jay - 30/5/2007  9:52 AM

If the purpose of the shield is to provide very short-term protection from flying debris, why does it have to weigh 20 tons?  A 2cm-thick, 5m-diameter piece of Boron Carbide armor would weigh 1 ton (it's one of the materials used in the ceramic plates soldiers use to stop rifle bullets).  I don't really know much about the stuff, but it's a ceramic with a high melting point (> 2300°C), and so should provide at least some short-term thermal protection as well.

The primary purpose of the "shield" is to provide 20 tons of ballast in addition to the 25 ton CEV, because the rocket needs the 40+ tons of payload in order to stay within its designed trajectory and g-loading envelope.  The crew protection is just a desirable side-effect.

An actual shield does sound like an interesting idea.

I realized that, but the thought of not having it because of needed payload on the lunar runs made me think about why you'd actually need to.  If you need 20 tons of ballast, you can make 19 tons of it water or something, and remove that during the more performance-limited launches, assuming a 1-ton (give or take) shield actually works and provides some useful amount of protection for increasing LOC numbers.
Title: RE: DIRECT v2.0
Post by: SolarPowered on 05/30/2007 05:21 PM
Quote
marsavian - 30/5/2007  10:10 AM

If there isn't enough fuel for a Jupiter 130 stretch the 8.4m tank until you do have enough.

I believe that you are extremely limited in stretching the tank, because the SRB attachment is at a fixed location, which has to be in the "interstaging" between the LOX and LH2 tanks.

I understand that this issue is a large part of why they need the 5-segment SRBs for the Ares V.  The longer SRBs allow them to stretch the tanks in the core.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 05:26 PM
Lee Jay,
I was wondering what other materials might be possible to use for a shield, but don't know much about any of the relevant materials.   Thanks for making the suggestion.

A quick back-of-the-envelope calculation does indeed confirm that a 5.0m diameter  Boron Carbon sheet, 2cm thick, would mass about 989kg assuming a 'nominal' 2.52grams/cm3 density.

I would strongly suggest locating the sheet between the CM heatshield and the SM body and accepting the performance hit throughout all missions.   My reasoning is that the Apollo-13 Service Module explosion did damage the Command Module's heatshield (although not sufficiently that we lost the crew, thank heavens) and a ballistic shield here would offer crew protection in the event of even a similar Service Module failure.

I don't know if 2cm is thick enough for this particular application, but considering we're talking about aluminium structures in the Core/EDS, this 'appears' like it might be sufficient.

A 1 ton performance hit like this still isn't possible using Ares-I, but if this addition were to just increase crew safety margins by 30%, we can match Ares-I's LOC figures.   Any more improvement than that and DIRECT goes into the lead.

The thing I really like about this is how relatively cheap such an improvement would be.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 05:30 PM
Actually thinking about this a little more, a 0.5cm thick B/C shield on the Service Module would probably be sufficient, and then a 2cm thick second shield located below the Service Module would allow the SM to still perform Aborts after the LAS has been ejected, even if the LV itself suffers serious failures.

Ross.
Title: RE: DIRECT v2.0
Post by: clongton on 05/30/2007 05:30 PM
Quote
marsavian - 30/5/2007  1:10 PM
If there isn't enough fuel for a Jupiter 130 stretch the 8.4m tank until you do have enough.
Fundamental premise of the Direct architecture is to use existing flight articles as close to "as-is" as can be. ET changes are limited to wall thickness milling differences and external mounting. To do things like stretching the ET takes us back to v1, which was a step-too-far. IF the Direct architecture, or something similar, gets adopted as baseline, lots of growth options become available. But for now, they are off the table.
Title: Re: DIRECT v2.0
Post by: clongton on 05/30/2007 05:37 PM
Quote
kraisee - 30/5/2007  1:30 PM

Actually thinking about this a little more, a 0.5cm thick B/C shield on the Service Module would probably be sufficient, and then a 2cm thick second shield located below the Service Module would allow the SM to still perform Aborts after the LAS has been ejected, even if the LV itself suffers serious failures.
Ross.
Oh the wonders of margin. Now that's why we refer to it as the holy grail of launch vehicle design. :)
Jupiter has it, Ares doesn't.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/30/2007 05:38 PM
I picked 2cm out of the air because I saw a shot on the Discovery channel where a guy held up a piece that looked to be a little under an inch thick and then fired a round from an AR-15 at it.  The round didn't go through.  That piece was wrapped with some cloth made out of one of the super fibers like Kevlar or Spectra or something, but that wasn't the stopping power for the unit.

I'm not clear on the failure modes for the abort system for the 1 in 10 times it fails to save the crew.  Without that knowledge, I don't know if even a 100% effective shield would eliminate any of them.  It's just a thought.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/30/2007 06:09 PM
Silicon Nitride and is already used in aerospace applications.

http://www.accuratus.com/silinit.html
http://en.wikipedia.org/wiki/Silicon_nitride
http://www.azom.com/details.asp?ArticleID=53
http://designinsite.dk/htmsider/m1017.htm

Silicon nitride (Si3N4) is light, hard, and has low thermal expansion coefficent. It has high mechanical strength, fracture toughness, and it is resistant to deformation at room temperature as well as at elevated temperatures.

Si3N4 differs from other ceramics because it doesn't melt, but, between 1800 and 1900 °C, it decomposes and sublimates into Si and N. However, stabilised forms can be made.

The most common applications are for engine parts (valves, pistons, etc.), energy plants (gas turbines, diesel engines etc.), and ultra high-temperature applications. Particulary important is its corrosion resistance (jigs and tools).
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 06:09 PM
There appear to be a plethora of ballistic armour shield materials available.   Stuff such as carbon kevlar composites used for the Apache helicopter's fuselage look like possibilities too.

Trade studies would be required to find the right materials for the particular application we're after.   But I think we can provide data on one or two potential "examples" and integrate them into the basic proposal easily.

Perhaps we should simply 'budget' for something like a 300kg shield between the CM/SM, and then a 1mT shield between the SM/LV.   This should be more than sufficient mass allocation.

This would offer an extra layer of protection for both the Crew Module and the Service Module from virtually all likely explosive events.   Heck, the shield inside the SM would also offer additional micrometeorite protection for the CM heatshield during missions - even if the SM were damaged.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 06:30 PM
marsavian - Is there any data about Si3N4 operating in cold-soak vacuum conditions such as those it would experience in space?

Whatever material is used it will have to work for >6 months in space conditions.   Being in next to the heatshield it is unlikely to be exposed to the sun, but in the shade it will experience very cold temperatures and needs to remain non-brittle in such an environment.

I don't have any such data on any of the materials suggested so far.   Trade Studies are needed.

Ross.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/30/2007 06:34 PM
This is more like it Ross, giving DIRECT unique safety capabilities and factors Ares I hasn't got due to its lower lift capability. Just need to quantify it over time and keep working the numbers until the safety factor is greater than Ares I even in Lunar missions. Good luck !
Title: Re: DIRECT v2.0
Post by: clongton on 05/30/2007 06:53 PM
A Blast Shield to protect Orion from a catastrophic LV failure.

That is such an obvious use for some of Jupiter’s margin that absolutely nobody on the Direct team thought of it. Talk about being too close to the forest to see the trees! Right from the very beginning of version 1, people were thinking of ways to use the margin in the launch vehicle, and all of us were oriented toward using it in mission mode. None of us ever thought about backing some of that margin back into the design to make the entire system safer.

It just goes to show us that none of us have all the answers, and that is one of the great strengths of a forum like this one, and a strength of a “team” approach to designing a launch vehicle, where everyone has an opinion or an idea, or a thought, and EVERYONE'S thoughts and opinions are valued. We are greater than the sum of our parts when we do things like this.

This thread was established in order to get feedback, critiques and suggestions. We have been getting all three, and all of it has been valuable. Thank you all, and thank you Lee Jay for showing us what was right in front of our face.

Everyone – thank you and please continue.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/30/2007 06:58 PM
Quote
kraisee - 30/5/2007  1:30 PM

marsavian - Is there any data about Si3N4 operating in cold-soak vacuum conditions such as those it would experience in space?

Whatever material is used it will have to work for >6 months in space conditions.   Being in next to the heatshield it is unlikely to be exposed to the sun, but in the shade it will experience very cold temperatures and needs to remain non-brittle in such an environment.

I don't have any such data on any of the materials suggested so far.   Trade Studies are needed.

Ross.

Is the SSME a good example ? ;-)

http://www.dfrc.nasa.gov/Newsroom/X-Press/1995/xp-95-04.html


New shuttle main engine being readied for flight

NASA has successfully completed testing a new high pressure liquid oxidizer turbopump and is ready to fly an upgraded main engine for the first time this coming June.

Final certification of the new liquid oxygen high pressure turbopump took place on March 15. The new pumps underwent a test program that is equivalent to 40 space shuttle flights.

The high pressure liquid oxygen pumps used in the current SSME must be removed after each flight for inspection. The new pumps will not need any detailed inspection until they have flown 10 times. The new pumps also are expected to increase safety margins and reliability for the SSMEs. These engines provide about 1.5 million pounds of thrust during launch of the shuttles into low earth orbit.

The new pumps also incorporate state of the art technology in the design. The pump housing is produced through a casting process, thereby eliminating all but six of the 300 welds that exist in the current pump. Eliminating welds is one of the keys to increasing safety margins on the main engines.

A new ball bearing material - silicon nitride (a type of ceramic) - is also used on the new pump. Silicon nitride offers several advantages over the steel bearings currently in use. The material is 30 percent harder than steel and has an ultra-smooth finish which allows for less friction during pump operation. Friction creates heat that leads to wear on the bearings. These new ceramic bearings eliminate concerns over excessive wear to the pump-end ball bearing.


Along with the new turbopump, the upgraded engine will have a new two-duct powerhead. The new powerhead will significantly improve fluid flows within the engine system by decreasing pressure, reducing maintenance and enhancing overall performance of the engine. It will replace three smaller fuel ducts in the current design with two enlarged ducts to achieve improve engine performance.

On shuttle mission STS-70, planned for June, one SSME will be a new Block I engine, while the remaining two engines will be the standard SSME design. The first flight planned to incorporate the new pumps into all three engines is STS-73, currently targeted for launch next September.

Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/30/2007 06:59 PM
Quote
kraisee - 30/5/2007  12:09 PM
Trade studies would be required to find the right materials for the particular application we're after.   But I think we can provide data on one or two potential "examples" and integrate them into the basic proposal easily.

Wait a minute.  That question I mentioned above about understanding why the abort system would fail to save the lives of the crew needs to be answered first.  Adding a ballistic shield doesn't help if the failure mode is avionics, or g-load, or depresurization or whatever.

Are you sure that a shield would actually increase the LOC number?  Is there some known rationale behind that assumption?  If there is, and there have been some studies on this, then you can make a rational argument.  If not, I think there would need to be first.  Where did that 1 in 10 number for the abort system come from?

Title: Re: DIRECT v2.0
Post by: clongton on 05/30/2007 07:13 PM
Quote
Lee Jay - 30/5/2007  2:59 PM

Quote
kraisee - 30/5/2007  12:09 PM
Trade studies would be required to find the right materials for the particular application we're after.   But I think we can provide data on one or two potential "examples" and integrate them into the basic proposal easily.

Wait a minute.  That question I mentioned above about understanding why the abort system would fail to save the lives of the crew needs to be answered first.  Adding a ballistic shield doesn't help if the failure mode is avionics, or g-load, or depresurization or whatever.

Are you sure that a shield would actually increase the LOC number?  Is there some known rationale behind that assumption?  If there is, and there have been some studies on this, then you can make a rational argument.  If not, I think there would need to be first.  Where did that 1 in 10 number for the abort system come from?
We understand that the original question remains valid and needs to be answered. It goes to the very heart of the abort system and how well it functions. The blast shield becomes a final line of defense in the case that the abort system does not function properly, and the LV explodes with Orion still attached. The blast shield would probably save the spacecraft and the crew, whereas without it, the safety of the crew would be no better than a similar event with an Ares launcher. So yes, the blast shield definately increases the LOC number, and the safety of the astronauts aboard Orion.

If Ares had the margin to do it, this technique could be employed by that launch vehicle as well. The fact is that it does not have the capability to carry a shield, leaving the crew without a critical safety feature that can be built into the Jupiter as standard hardware.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 07:17 PM
Quote
marsavian - 30/5/2007  2:34 PM

This is more like it Ross, giving DIRECT unique safety capabilities and factors Ares I hasn't got due to its lower lift capability. Just need to quantify it over time and keep working the numbers until the safety factor is greater than Ares I even in Lunar missions. Good luck !

With the extra margin on performance all the DIRECT architectures support, we can easily implement these shields for all Lunar missions as well as LEO missions.

We can even carry one of these protective shields all the way through a Lunar mission to SM separation and re-entry.

I am already convinced that we have considerably better Lunar LOM numbers than Ares.

We absolutely have higher Lunar mission LOC numbers after the ascent phase already, and the CM/SM shield promises an increase there too.

Evaluating safety numbers for the ascent is the only "gray" area we have right this minute.   Analysis of this has already started in FIRST and is looking promising.   It is a unique concept though, with little in the way of previous precedent, so we shall see what comes of it.

Ross.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/30/2007 07:31 PM
Perhaps the blast shield could have shock absorbers to dampen a blast.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 07:50 PM
The target is to provide as much protection during each phase of the mission.

The primary purpose of a shield below the Service Module would be to absorb any shrapnel strikes of any structures below coming up and damaging the CEV itself, and to also create a physical barrier for any explosion events immediately below the SM.

Challenger clearly demonstrates that the ET does not actually "explode" in these catastrophic events.   Liquid Hydrogen burns in localized areas, but not fast enough to actually qualify as a real explosion.   Still, these limited events and rapid depressurisations can send burning fuel and shrapnel in any direction, so we are trying really to protect the CEV from those events during the ascent phase of the mission.

The SM must be protected from the Launch Vehicle itself because after the LAS has been jettisoned, it is the Service Module which performs all the aborts from a failing vehicle.

Yet the CEV itself poses a danger, both on its own and also in catastrophic events.   It contains substantial quantities of explosive propellants and other pressurized materials - all of which are capable of damaging the Command Module located immediately above.   Be it a mechanical failure inside the SM itself (Apollo 13), or damage from shrapnel coming from another source (Challenger) or even failure due to micrometeorite strike, the SM is a very localized source of potential damage to a Crew Module.

This is where a shield on top of the SM comes in - a shield located on the top of teh SM, immediately below the Heatshield, should be able to protect the CM from almost anything the SM might throw at it.

LAS removes the CM during the early phases of the ascent, so both shields offer protection thorough that phase of the flight.

The CM/SM shield offers a crew protection from Service Module problems during the last half of ascent all the way through separation, circularization and all the way through to the end of the mission.

On LOR missions, with the EDS located to the aft, the SM/LV shield even offers protection from a catastrophic failure of the EDS during a TLI burn.

All of these are very important additional safety features Jupiter can support, but which Ares-I makes impossible to implement.

Ross.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/30/2007 08:30 PM
Working with the blast shield it could deploy small fins at the base to help stabilize it.  Otherwise it might go into a tumble.
This is probably too much detail but thought I would throw it out there anyway.
Title: Re: DIRECT v2.0
Post by: on 05/30/2007 08:49 PM
A blast shield doesn't need to be complex. Imagine a simple water tank, where the mass of the water is the shield.

You'd be surprised how effective just plain water can be. Besides, if you orbit it, you can use it too.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/30/2007 09:07 PM
It would probably make more sense to put the fins there permanently.   Maybe 6 fairly small fins at the base of the service module.
AKA the KISS principle.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/30/2007 11:28 PM
Ross,

Some hard comparison numbers between Boron Carbide and Silicon Nitride

http://www.azom.com/details.asp?ArticleID=2254
http://www.azom.com/Details.asp?ArticleID=2263

Boron Carbide is harder, lighter with greater elasticity whereas Silicon Nitride is stronger, non-porous and with greater heat/oxidizing resistance. Boron Carbide also stops Neutron radiation which might be useful in Space ;-).

Title: Re: DIRECT v2.0
Post by: Lee Jay on 05/30/2007 11:36 PM
Quote
nobodyofconsequence - 30/5/2007  2:49 PM

A blast shield doesn't need to be complex. Imagine a simple water tank, where the mass of the water is the shield.

You'd be surprised how effective just plain water can be. Besides, if you orbit it, you can use it too.

Absolutely true, but an extremely heavy solution if you don't need the water.

Lee Jay
Title: Re: DIRECT v2.0
Post by: kraisee on 05/30/2007 11:40 PM
I'm not sure fins will be of much use.

The LAS rides on the LV all the way through the atmospheric portion of the ascent and is designed to operate in just a fraction of a second after an abort condition is detected, taking just the Crew Module off, and leaving the Service Module behind.

The SM only performs aborts much later in the ascent, once the LAS has been jettisoned away.

There just isn't a scenario where the SM performs any escape duties while still inside an atmospheric environment.


In either case, a ballistic shield would only really be of benefit for no more than a couple of seconds, while whatever escape system is utilised (LAS or SM) is fired and begins to move the CM away.

The shield under the SM would hopefully protect the SM sufficiently to act either as a "gap filler" between the failing LV and the CM while the LAS boosts it away, or it would act as a means of stopping shrapnel/blast-waves from damaging the J-2X while it ignites and gets the CM the heck out of dodge.

Ross.
Title: Re: DIRECT v2.0
Post by: MKremer on 05/31/2007 01:28 AM
Quote
kraisee - 30/5/2007  6:40 PM

I'm not sure fins will be of much use.

Ross.

IMO fins will add nothing to control/safety; and would end up only adding extra booster mass, which accordingly takes away even more payload mass available to orbit.
Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/31/2007 03:02 AM
Quote
MKremer - 30/5/2007  8:28 PM

Quote
kraisee - 30/5/2007  6:40 PM

I'm not sure fins will be of much use.

Ross.

IMO fins will add nothing to control/safety; and would end up only adding extra booster mass, which accordingly takes away even more payload mass available to orbit.
My thinking was that if the booster exploded the forces of the blast would not be even & would throw the CEV/SM into a tumble.   If it turns just 90 degrees it might rip off tower.  I don't know, maybe its strong enough to withstand that.   Hopefully its not pointing the wrong way when the las motor fires.   It might take it right through the debris field.

 I was trying to think of a way to keep it pointing the right direction.
Title: Re: DIRECT v2.0
Post by: mike robel on 05/31/2007 03:17 AM
I should think it would be better to integrate this ballistic shield with the main CSM structure so as to also provide radiation shielding.  To loft  the thing with no purpose but ballistic protection in the unlikely event of a booster explosion, not specifically aimed at the CM seems somewhat wasteful to me.  As opposed to a high energy long rod KE penetrator aimed at a tank.  Enough KE can always be found to penetrate any armor, which is what a ballistic shield is anyway.  A somewhat less dense ceramic mix or mixture of Kevlar, Gortex, and other high density fabrics in addition to ceramics may be all that is necessary for an effective shield for a relatively low energy event  - not like a DU penetrator aimed at the target with velocities approaching 2 miles per second.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/31/2007 03:21 AM
Veedriver22,
It's a fair point.   It wasn't the force of any "explosion" or the sudden depressurisation of the ET which caused Challenger to break up, it was the fact that when the ET started to fall apart, the struts mounting the orbiter in place also failed and pushed the spacecraft sideways to the rapidly moving airflow.

At just a little after max-Q, where the accident happened, the pressure is very high.   They are travelling at about 1.5 times the speed of sound, and going past 35,000ft altitude.   In these conditions, the vehicle suddenly found itself flying partially "sideways", and the air itself started ripping the whole orbiter apart.

Given this experience, it isn't unreasonable to think that a catastrophic LV failure below a CEV might cause it too, to be twisted off of it's nominal trajectory path.

The advantage I do see though, is that the Orion has a very stable aerodynamic shape, which ought to help re-align it naturally in a fairly quick fashion.

Of course, the LAS should be able to just yank the CM off within a fraction of a second of major problems occurring, and I suspect the force of its thrust is going to be the most considerable force being applied to the CM at the time.

I would suspect that the LAS & Orion teams are planning their designs in the full knowledge that the Orion's orientation may not actually be perfectly aligned with the nominal trajectory in the case of an emergency abort.   I'm sure its something they are already dealing with.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 05/31/2007 03:36 AM
Quote
mike robel - 30/5/2007  11:17 PM

I should think it would be better to integrate this ballistic shield with the main CSM structure so as to also provide radiation shielding.  To loft  the thing with no purpose but ballistic protection in the unlikely event of a booster explosion, not specifically aimed at the CM seems somewhat wasteful to me.  As opposed to a high energy long rod KE penetrator aimed at a tank.  Enough KE can always be found to penetrate any armor, which is what a ballistic shield is anyway.  A somewhat less dense ceramic mix or mixture of Kevlar, Gortex, and other high density fabrics in addition to ceramics may be all that is necessary for an effective shield for a relatively low energy event  - not like a DU penetrator aimed at the target with velocities approaching 2 miles per second.

Agreed.   I think there's a lot of research which could be done in this area to protect crews.   the Boron Carbide looks like a fairly good radiation shielding in addition to it's ballistic properties, but a kevlar/carbon-fibre/Gortex also appear to be of great value too.   The most effective solution may well turn out to be a multi-layer composite material, with perhaps Silicone Nitride in one layer, together with a layer of something like Kevlar, and perhaps even a third layer of Silicone Nitride.   I'm not sure what order to place the different materials myself, but the overlapping performance characteristics of a multi-layer approach offers a lot of potential to this concept.

The DIRECT team is not really set-up to be able to research the particular materials ourselves, so we are researching a number of military sources for useful information currently to include in an addendum to our core report.   Data exists for all the armour types in use by the military today, and I'm sure the manufacturers of such things would be interested in a regular contract from NASA for their wares.

It is possible that we will take the approach of suggesting half a dozen different materials & composites which should be "trade studied" and then budget a reasonable mass allocation for such a system into our calculations, based on masses utilised in similar real-world applications.

This will allow us to press on without getting bogged down in the precise formulation of what the shield is actually made from.   We can present a series of basic safety numbers and costs based on a range of different materials, and then leave the rest to a deeper trade study later.

Ross.
Title: Re: DIRECT v2.0
Post by: zinfab on 05/31/2007 04:53 AM
I'd suggest finding ANY reference to "space flown" for any materials you suggest. It may be a way to limit your scope. Lack of "space flown" nicks the armor of your argument, if you'll pardon my expression. You rely on "Direct" principles. NASA may have a hard time answering media/political questions like:

"Why didn't NASA think a shield was needed for Ares I?"

While I'm as excited about this feature as ICES, the politics of ANYTHING that isn't necessary or immediately "ready" from the shuttle-derived equipment risks weakening the larger argument. Be ready to GIVE NASA the sound-byte (and thought out) answers to questions like that in your report.
Title: Re: DIRECT v2.0
Post by: renclod on 05/31/2007 06:56 AM
kraisee
Quote
- 30/5/2007  10:50 PM
 a shield located on the top of the SM, immediately below the Heatshield...  
You need to look at the footprint of debris from SM on entry.
A heavy armor plate might come down in one heavy piece surfing through the atmosphere.
Title: Re: DIRECT v2.0
Post by: marsavian on 05/31/2007 08:11 AM
Ross,

I think you probably have enough margin to completely encase the CM with a ballistic shield. I'm thinking of the benefit of general micrometeroid protection as well as a LV failure and MMods are the constant danger the longer you stay out in space. The weight applied in this place will do the most to decrease your LOC figure and the idea of a capsule shield is a potent concept that is easily understood and sold. It also makes your safety calculations much easier when you can rule out a whole class of MMods ;-).

We spend so much money sending Astronauts out in Space but once we do we rely on chance for their continued safety ! With modern technology we can do much better and should !! Along with your heavy SM bottom cap I think you now have the safety aspect sorted, you just need to quantify and solidify it now in the proposal. Fwiw I think you should have a Boron Carbide outer shield and a Silicon Nitride inner shield. The Boron Carbide will stop particle momentum and neutron radiation and the Silicon Nitride will stop thermal energy and provide the last strong defence of structural integrity.
Title: Re: DIRECT v2.0
Post by: neviden on 05/31/2007 09:35 AM
Quote
renclod - 31/5/2007  8:56 AM

kraisee
Quote
- 30/5/2007  10:50 PM
 a shield located on the top of the SM, immediately below the Heatshield...  
You need to look at the footprint of debris from SM on entry.
A heavy armor plate might come down in one heavy piece surfing through the atmosphere.
Why dump it?

Keep it in LEO. I am sure the folks on ISS would be happy to have few of them postioned outside of their modules. It would sure reduce the chances of a meteroid puncture.
Title: Re: DIRECT v2.0
Post by: rumble on 05/31/2007 01:18 PM
Quote
neviden - 31/5/2007  4:35 AM

Quote
renclod - 31/5/2007  8:56 AM

kraisee
Quote
- 30/5/2007  10:50 PM
 a shield located on the top of the SM, immediately below the Heatshield...  
You need to look at the footprint of debris from SM on entry.
A heavy armor plate might come down in one heavy piece surfing through the atmosphere.
Why dump it?

Keep it in LEO. I am sure the folks on ISS would be happy to have few of them postioned outside of their modules. It would sure reduce the chances of a meteroid puncture.
Except for ISS missions (and few are scheduled), the SM won't be anywhere near ISS, and a lunar or mars return, you'd have to brake it into orbit to even consider this.

Good point about the debris footprint.  A 1-ton heat-resistant 5m frisbee could land nearly intact, and could travel a significant distance outside the rest of the debris field.
Title: RE: DIRECT v2.0
Post by: renclod on 05/31/2007 03:18 PM
spacelogistics.mit.edu/pdf/Shull_IAC2006.pdf
Quote
AN INTEGRATED MODELING TOOL FOR SUSTAINABLE SPACE EXPLORATION
57th International Astronautical Congress 2006
Mrs. Sarah A. Shull; Ms. Erica L. Gralla; Mr. Nii Armar; Prof. Olivier de Weck, PhD Massachusetts Institute of Technology (MIT), Cambridge, MA, U.S.A.
This work was completed as part of the Interplanetary Supply Chain Management & Logistics Architectures project financially supported by NASA under contract NNK05OA50C.
Prof. Olivier de Weck and Prof. David Simchi-Levi, Massachusetts Institute of Technology, serve as the principal investigators, with Dr. Martin Steele from NASA’s Kennedy Space Center as COTR. Co-investigators are Dr. Robert Shishko (JPL) and Mr. Joe Parrish (Payload Systems
Inc.).
>>both the 1-launch equivalent and 2-launch architectures have better performance to cost ratios than the 1.5- launch baseline and should strongly be considered for use in Constellation.<<

Quote
1-LAUNCH EQUIVALENCY ARCHITECTURE

For the 1-launch equivalency architecture, it was found that either increasing LSAM DS propellant mass, increasing EDS propellant mass or some hybrid of the two, was sufficient to achieve mass closure (while keeping cargo and operations mass constant). After careful analysis, it was determined that a hybrid option, in which EDS propellant mass was increased by 18% and the LSAM DS propellant mass by 17% over the baseline, offered the best solution. This option best combines the robustness of the EDS modification strategy with the relatively
low launch mass and mass to LEO of the LSAM DS modification strategy. This option
was henceforth carried forward as the representative of the 1-launch Equivalency architecture and formed the basis of the Ares V+ launch vehicle.

2-LAUNCH ARCHITECTURE

The best 2-launch option was found to be what is nominally a 2 x 80mT architecture. In reality it is an asymmetric 87mT + 70mT to LEO architecture in which both launches share common boosters and core stages. The reduced size Ares V- LVs were modeled as a 4 segment solid rocket booster (SRB) instead of a 5 segment used in the 1.5-launch specification plus a 1.5-launch specification core stage with a slightly reduced propellant load. The EDS was reduced in size due to less suborbital burn time, but contains the same amount of propellant in LEO as the baseline EDS.




Title: Re: DIRECT v2.0
Post by: veedriver22 on 05/31/2007 05:06 PM
Quote
rumble - 31/5/2007  8:18 AM

Quote
neviden - 31/5/2007  4:35 AM

Quote
renclod - 31/5/2007  8:56 AM

kraisee
Quote
- 30/5/2007  10:50 PM
 a shield located on the top of the SM, immediately below the Heatshield...  
You need to look at the footprint of debris from SM on entry.
A heavy armor plate might come down in one heavy piece surfing through the atmosphere.
Why dump it?

Keep it in LEO. I am sure the folks on ISS would be happy to have few of them postioned outside of their modules. It would sure reduce the chances of a meteroid puncture.
Except for ISS missions (and few are scheduled), the SM won't be anywhere near ISS, and a lunar or mars return, you'd have to brake it into orbit to even consider this.

Good point about the debris footprint.  A 1-ton heat-resistant 5m frisbee could land nearly intact, and could travel a significant distance outside the rest of the debris field.
They could be used on the moon base too.   Of course then you have to figure out how to get them on the moon surface.
Title: Re: DIRECT v2.0
Post by: zinfab on 05/31/2007 09:02 PM
While I agree that a complete Orion encasement is a "good idea," this is VERY late in the design stage of Orion to introduce entirely new things (and expect to be accepted).
Title: Jupiter-232 1-Launch model?
Post by: BogoMIPS on 05/31/2007 09:22 PM
Wow, I went away for a while, and missed just about everything around here. ;)

I was originally going to post this in the DIRECTv2 thread, but as it's sufficiently off-topic, I decided to start it separately.

DIRECT v2 looks like a good step in the right, sensible direction.

One question I've always had about the VSE and Ares ideas is that it's going to take two launches every time you want to get a crew to a permanent lunar outpost, assuming we can get to that point.

It seems desirable that, at some point, there should be an ability to perform a single launch to rotate a crew at such a base.

For S's and G's, I'm curious.  If we came up with a smaller capsule/lander combo (probably modern Apollo/LEM combo for comparison's sake), the 232 looks just a shade short of performance to enable Apollo-style sorties.

Any thoughts on if one of the other variants of the Jupiter could enable a single-launch crew rotation capability for a lunar outpost?
Title: Re: Jupiter-232 1-Launch model?
Post by: kraisee on 05/31/2007 09:30 PM
This should probably be over in the DIRECT v2.0 thread.

Theoretically, yes.   But it isn't the best method.

Theoretically it would be possible to exactly duplicate Apollo missions, but using modern materials you could make all the hardware slightly lighter, and that could then probably fly on a single J-232.

But a 2-launch architecture is actually a more sensible approach.

In the early years of the program, a second launch vehicle costs perhaps 10% extra to the overall cost of each mission (the LSAM alone will costs more than double the cost of both LV's put together) and you basically get double the mass going to the moon.   This makes a 2-launch approach a very cost-effective solution.

In the future though, when the program is fully established, a single launcher solution is possible again.   You need ISRU fuel processing facilities on the Lunar surface, and something DC-X like as a reusable lander/launcher acting as a "Lunar Taxi" to and from Lunar orbit.   At that point you only need a single Heavy Lift Launcher to send a CEV, Crew and Cargo to meet the "Lunar Taxi".

Ross.
Title: Re: DIRECT v2.0
Post by: marsavian on 06/01/2007 12:09 AM
Orion is meant to be used to explore the solar system for this whole century. It's never too late to get something right. Do we want to send Astronauts out in a tin can or a proper SPACEship ? There will be several iterations of Orion anyway for each mission so it is in constant development. It's also a very clear advantage DIRECT would have over Ares I, it will make the latter look obsolete 20th century technology and relying on chance for longterm crew safety. It also is something that could very easily capture the public's imagination, a true Apollo on Steroids, a spaceship that begins to resemble a bit more the fantasy ones that so capture our imagination in Star Trek, Star Wars etc, they all have 'shields' yeah ? ;-) It's the missing nail that this proposal needs to seal Ares I's coffin, at least on an intellectual level.
Title: Re: DIRECT v2.0
Post by: on 06/01/2007 12:55 AM

Quote
rumble - 31/5/2007  8:18 AM  A 1-ton heat-resistant 5m frisbee could land nearly intact, and could travel a significant distance outside the rest of the debris field.

Which is why I spoke of water. It's excellent for slowing fragments, absorbs enormous amounts of heat before vaporization, and by being incompressible is great for blunt force impacts. Not to mention necessary for life in space and on the moon, and useful  for radiation shielding.

Plus, if it falls apart, it disperses. Really simple stuff here. But its heavier than Kevlar. If you use it anyways, what does it matter its weight?

Title: Re: DIRECT v2.0
Post by: kraisee on 06/01/2007 04:30 AM
A shield on top of the SM isn't too difficult to implement even at this stage of development.   Certainly one mounted under the SM, in the Spacecraft Adapter (SCA) would not affect the Orion's design at all.

An all-encompassing shield though, would probably have to go into a later version of Orion - perhaps the Block-II variant could use it.

It would seem to end up tipping the scales a little over 25mT though, so obviously, Ares-I couldn't ever successfully lift it.   It is out of the running if you want this sort of protection for crews.   You simply *must* have a more powerful launcher if you ever want this capability.

In the EELV world, you would probably need an upgraded Delta-IV to lift this sort of CEV.   In the EELV field you would need either Atlas-V Heavy or Atlas Phase 2, but EELV's don't retain the workforce so aren't going to be politically acceptable.   In the SDLV field, you need something like Jupiter-120, ESAS LV-24/25 or Ares-V - though the latter two are too expensive to develop as NASA's first generation booster.

Ross.
Title: Re: DIRECT v2.0
Post by: renclod on 06/01/2007 09:08 AM
marsavian
Quote
- 1/6/2007  3:09 AM

a tin can or a proper SPACEship ? ...at least on an intellectual level

On an engineering level, it is easyer to extract a "tin can" from the launch stack in an aborted ascent, experimenting high aerodynamic pressure and quite possibly an ugly angle of attack.

Every extra pound or kilo you put on the capsule makes so much more difficult to solve the LAS problem.

This is the reason why several contractors ( 2004 CEV study ) concluded that the way to go is to minimize the capsule that needs to be extracted in a launch abort, and adopt the Command Module + Service Module + Mission Module configuration.

Who ?

Andrews Space Inc., Seattle
Lockheed Martin Corp., Denver
Northrop Grumman Corp., El Segundo, Calif
The Boeing Co., Huntington Beach, Calif

The "tin can" Orion is just a taxi to take your crew to the "spaceship that begins to resemble a bit more the fantasy ones that so capture our imagination in Star Trek, Star Wars etc..."

In the Apollo era, the CM mass was 5,806 kg and the LES mass was 4,173 kg.

In the Orion era, so far, the CM is ~9,000 kg and the LAS is ~4,500 kg. And counting.



Title: Re: DIRECT v2.0
Post by: marsavian on 06/01/2007 10:12 AM
The command module is the lifeboat and is the only piece of equipment that is constant throughout the whole mission and that returns to Earth. The capsule shield would provide greater protection through atmospheric re-entry as well if the composition was constructed with that in mind too. It all adds to improving the LOC factor which is what it's all about. Adding weight in this direction is not wasted weight because losing crew will sour VSE and its support in the public's mind as Challenger and Columbia took the gloss of the Space Shuttle. DIRECT has margin to burn, 1-2 mT of it can be easily spared to overturn its only theoretical weakness against Ares I and use that against it. Just get a bigger more powerful LAS, weight is not a problem in DIRECT.
Title: Re: DIRECT v2.0
Post by: Will on 06/01/2007 01:45 PM
I'm puzzled by LOR-LOR figures in v2.0. Even using the optimistic mass fraction of the current design, EDS plus residuals is 23 mT, and payload adapter is four. Useful payload/departure propellant is 108, for a total IMLEO of 135. Propellant to send the stack to TLI would be about 69 mT so the stack would be 66 mT at burnout. Subtracting the EDS and payload mount gives 39 mT to TLI, not 50 to LOI.

Will
Title: Re: DIRECT v2.0
Post by: tankmodeler on 06/01/2007 02:23 PM
Quote
Quote
A heavy armor plate might come down in one heavy piece surfing through the atmosphere.
Good point about the debris footprint.  A 1-ton heat-resistant 5m frisbee could land nearly intact, and could travel a significant distance outside the rest of the debris field.
There's no fundamental reason that an energy absorbing shield _has_ to be monolithic. A shield made of overlapping/interlocking plates/fabrics will offer virtually as much protection while obviating any "re-entry frisbie" concerns. There are many design solutions to providing protection while permitting flexibility, burn-up or dispertion on re-entry. This is not a major issue.

As was said, this is not armour on an MBT looking to stop DU penetrators doing 3500 m/s. This is relatively low velocity stuff, much more akin to a "flak" vest than a bulletproof vest and there is a huge difference in the two.

Paul
Title: RE: DIRECT v2.0
Post by: Jim on 06/01/2007 02:53 PM
Quote
renclod - 31/5/2007  11:18 AM

spacelogistics.mit.edu/pdf/Shull_IAC2006.pdf
Quote
AN INTEGRATED MODELING TOOL FOR SUSTAINABLE SPACE EXPLORATION
57th International Astronautical Congress 2006
Mrs. Sarah A. Shull; Ms. Erica L. Gralla; Mr. Nii Armar; Prof. Olivier de Weck, PhD Massachusetts Institute of Technology (MIT), Cambridge, MA, U.S.A.
This work was completed as part of the Interplanetary Supply Chain Management & Logistics Architectures project financially supported by NASA under contract NNK05OA50C.
Prof. Olivier de Weck and Prof. David Simchi-Levi, Massachusetts Institute of Technology, serve as the principal investigators, with Dr. Martin Steele from NASA’s Kennedy Space Center as COTR. Co-investigators are Dr. Robert Shishko (JPL) and Mr. Joe Parrish (Payload Systems
Inc.).
>>both the 1-launch equivalent and 2-launch architectures have better performance to cost ratios than the 1.5- launch baseline and should strongly be considered for use in Constellation.<<

Quote
1-LAUNCH EQUIVALENCY ARCHITECTURE

For the 1-launch equivalency architecture, it was found that either increasing LSAM DS propellant mass, increasing EDS propellant mass or some hybrid of the two, was sufficient to achieve mass closure (while keeping cargo and operations mass constant). After careful analysis, it was determined that a hybrid option, in which EDS propellant mass was increased by 18% and the LSAM DS propellant mass by 17% over the baseline, offered the best solution. This option best combines the robustness of the EDS modification strategy with the relatively
low launch mass and mass to LEO of the LSAM DS modification strategy. This option
was henceforth carried forward as the representative of the 1-launch Equivalency architecture and formed the basis of the Ares V+ launch vehicle.

2-LAUNCH ARCHITECTURE

The best 2-launch option was found to be what is nominally a 2 x 80mT architecture. In reality it is an asymmetric 87mT + 70mT to LEO architecture in which both launches share common boosters and core stages. The reduced size Ares V- LVs were modeled as a 4 segment solid rocket booster (SRB) instead of a 5 segment used in the 1.5-launch specification plus a 1.5-launch specification core stage with a slightly reduced propellant load. The EDS was reduced in size due to less suborbital burn time, but contains the same amount of propellant in LEO as the baseline EDS.





Ross and Smetch, why aren't you jumping all over this. Isn't it independent confirmation of the 2 launch scenario?
Title: Re: DIRECT v2.0
Post by: Bill White on 06/01/2007 02:54 PM
Quote
nobodyofconsequence - 31/5/2007  7:55 PM

Quote
rumble - 31/5/2007  8:18 AM  A 1-ton heat-resistant 5m frisbee could land nearly intact, and could travel a significant distance outside the rest of the debris field.

Which is why I spoke of water. It's excellent for slowing fragments, absorbs enormous amounts of heat before vaporization, and by being incompressible is great for blunt force impacts. Not to mention necessary for life in space and on the moon, and useful  for radiation shielding.

Plus, if it falls apart, it disperses. Really simple stuff here. But its heavier than Kevlar. If you use it anyways, what does it matter its weight?


Spare water in LEO would be a very, very valuable asset.

One idea would be to sell a used water based ballistic shield to a NewSpace fuel depot operator who could then crack it into H2 and O2 to sell back to NASA.

NASA could sell the water for the then current cost per kilo to lift mass via Proton and apply the proceeds to reduce the launch costs for Orion.

Toss in the external tank and Space Island Group is back in business! :-)

Of course, this undermines the idea of a NASA monopoly for LEO operations. Some would see this as a feature and others would see this as a bug.
Title: Re: DIRECT v2.0
Post by: Jim on 06/01/2007 03:25 PM
Quote
Bill White - 1/6/2007  10:54 AM

Spare water in LEO would be a very, very valuable asset.

One idea would be to sell a used water based ballistic shield to a NewSpace fuel depot operator who could then crack it into H2 and O2 to sell back to NASA.

NASA could sell the water for the then current cost per kilo to lift mass via Proton and apply the proceeds to reduce the launch costs for Orion.
.

???

This would mean another rendezous and more ops.  Anyways, don't need the Newspace middleman then.  The whole point of the depot was commercial launches.  Also NASA doen't need the depot for decades if it has Direct
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/01/2007 03:28 PM
Quote
tankmodeler - 1/6/2007  8:23 AM

Quote
Quote
A heavy armor plate might come down in one heavy piece surfing through the atmosphere.
Good point about the debris footprint.  A 1-ton heat-resistant 5m frisbee could land nearly intact, and could travel a significant distance outside the rest of the debris field.
There's no fundamental reason that an energy absorbing shield _has_ to be monolithic.

Exactly.

http://www.pinnaclearmor.com/body-armor/dragon-skin.php
Title: RE: DIRECT v2.0
Post by: Smatcha on 06/01/2007 03:45 PM
Quote
Jim - 1/6/2007  7:53 AM

Quote
renclod - 31/5/2007  11:18 AM

spacelogistics.mit.edu/pdf/Shull_IAC2006.pdf
Quote
AN INTEGRATED MODELING TOOL FOR SUSTAINABLE SPACE EXPLORATION
57th International Astronautical Congress 2006
Mrs. Sarah A. Shull; Ms. Erica L. Gralla; Mr. Nii Armar; Prof. Olivier de Weck, PhD Massachusetts Institute of Technology (MIT), Cambridge, MA, U.S.A.
This work was completed as part of the Interplanetary Supply Chain Management & Logistics Architectures project financially supported by NASA under contract NNK05OA50C.
Prof. Olivier de Weck and Prof. David Simchi-Levi, Massachusetts Institute of Technology, serve as the principal investigators, with Dr. Martin Steele from NASA’s Kennedy Space Center as COTR. Co-investigators are Dr. Robert Shishko (JPL) and Mr. Joe Parrish (Payload Systems
Inc.).
>>both the 1-launch equivalent and 2-launch architectures have better performance to cost ratios than the 1.5- launch baseline and should strongly be considered for use in Constellation.<<

Quote
1-LAUNCH EQUIVALENCY ARCHITECTURE

For the 1-launch equivalency architecture, it was found that either increasing LSAM DS propellant mass, increasing EDS propellant mass or some hybrid of the two, was sufficient to achieve mass closure (while keeping cargo and operations mass constant). After careful analysis, it was determined that a hybrid option, in which EDS propellant mass was increased by 18% and the LSAM DS propellant mass by 17% over the baseline, offered the best solution. This option best combines the robustness of the EDS modification strategy with the relatively
low launch mass and mass to LEO of the LSAM DS modification strategy. This option
was henceforth carried forward as the representative of the 1-launch Equivalency architecture and formed the basis of the Ares V+ launch vehicle.

2-LAUNCH ARCHITECTURE

The best 2-launch option was found to be what is nominally a 2 x 80mT architecture. In reality it is an asymmetric 87mT + 70mT to LEO architecture in which both launches share common boosters and core stages. The reduced size Ares V- LVs were modeled as a 4 segment solid rocket booster (SRB) instead of a 5 segment used in the 1.5-launch specification plus a 1.5-launch specification core stage with a slightly reduced propellant load. The EDS was reduced in size due to less suborbital burn time, but contains the same amount of propellant in LEO as the baseline EDS.





Ross and Smetch, why aren't you jumping all over this. Isn't it independent confirmation of the 2 launch scenario?

Jim, we are expanding significantly on this important subject in the AIAA paper.  It represents yet another area where Direct’s 2xHLV approach complete overwhelms the best the Ares I/V approach could ever achieve.  From a mission planning stand point it not only improves significantly the mass to the lunar surface but increases the mission flexibility and protects or architecture against “unexpected” mass increases.  That way we don’t have to depend on “unscheduled” breakthroughs :)

Also this holistic approach used by MIT and us is something I tried to get ESAS to adopt but was obviously unsuccessful in that endeavor.  It was clear from my first discussions with the some of the key ESAS team members that Mike already had the answer. What Mike wanted from the ESAS team was the justification for those answers.

My mind begins to boggle at just how many more advantages we need to develop and detail in DIRECT in order for NASA’s upper management to get its collective head out of the sand.  It’s no small secret by those in the inner circle about who, how and why the Ares I/V   1.5 approach came about.

NASA is in a very uncomfortable state of collective cognitive dissonance.

http://en.wikipedia.org/wiki/Cognitive_dissonance

"Put simply, the experimenters concluded that many human beings, when persuaded to lie without being given sufficient justification, will carry out the task by convincing themselves of the falsehood, rather than telling a bald lie."

The whole article is good read by the way.  It fits our present dilemma to a t.

The defending and promoting the truth is the only way out of this unholy mess.  Unfortunately about 99% of the people who can discern and credibly articulate this truth derived their lively hood from NASA in one form or another.

Hope springs eternal.


Title: RE: DIRECT v2.0
Post by: RedSky on 06/01/2007 04:06 PM
Quote
SMetch - 1/6/2007  10:45 AM

"Put simply, the experimenters concluded that many human beings, when persuaded to lie without being given sufficient justification, will carry out the task by convincing themselves of the falsehood, rather than telling a bald lie."

The whole article is good read by the way.  It fits our present dilemma to a t.

The defending and promoting the truth is the only way out of this unholy mess.  Unfortunately about 99% of the people who can discern and credibly articulate this truth derived their lively hood from NASA in one form or another.

Hope springs eternal.

Unfortunately... this reminded me of this cartoon...

http://www.patandkat.com/pat/weblog/images/dilbert-lie.png
Title: Re: DIRECT v2.0
Post by: Bill White on 06/01/2007 04:54 PM
Quote
Jim - 1/6/2007  10:25 AM

Quote
Bill White - 1/6/2007  10:54 AM

Spare water in LEO would be a very, very valuable asset.

One idea would be to sell a used water based ballistic shield to a NewSpace fuel depot operator who could then crack it into H2 and O2 to sell back to NASA.

NASA could sell the water for the then current cost per kilo to lift mass via Proton and apply the proceeds to reduce the launch costs for Orion.
.

???

This would mean another rendezous and more ops.  Anyways, don't need the Newspace middleman then.  The whole point of the depot was commercial launches.  Also NASA doen't need the depot for decades if it has Direct

Yup, another NASA monopoly guy. What "NASA needs" is not co-extensive with what most benefits the American people and taxpayers.

If any fraction of the spare lift capability of Jupiter can be used to loft something sell-able to someone, that lowers the operational costs for NASA.




Title: Re: DIRECT v2.0
Post by: Jim on 06/01/2007 05:26 PM
Quote
Bill White - 1/6/2007  12:54 PM


Yup, another NASA monopoly guy. What "NASA needs" is not co-extensive with what most benefits the American people and taxpayer

No, just a realist.   I don't think NASA needs to provide service to LEO.  But I also newspace isn't anywhere close to provide anything real for awhile.

NASA selling and buying back water is just silly.  Also the extra logistics involved would make it  hardly worht the effort

Title: Re: DIRECT v2.0
Post by: Crispy on 06/01/2007 06:51 PM
Quote
If any fraction of the spare lift capability of Jupiter can be used to loft something sell-able to someone, that lowers the operational costs for NASA.

NASA are not allowed to sell launch services
Title: RE: DIRECT v2.0
Post by: PMN1 on 06/01/2007 06:55 PM
If there had been more problems and delays with the orbitter part of the system in the late 70's and talk of cancellation, what are the chances of being able to salvage a Direct or an Ares I/V system from the work already done or is it more likley that everything would be cancelled?
Title: RE: DIRECT v2.0
Post by: PMN1 on 06/01/2007 07:18 PM
What happens to the attachment points on the ET for the orbitter in the Direct and the Ares V approach - are they removed or are they going to stay there (less the struts) as its not worth removing them?
Title: Re: DIRECT v2.0
Post by: on 06/01/2007 07:20 PM
Quote
PMN1 - 1/6/2007 1:55 PM If there had been more problems and delays with the orbitter part of the system in the late 70's and talk of cancellation, what are the chances of being able to salvage a Direct or an Ares I/V system from the work already done or is it more likley that everything would be cancelled?
The politics were different then. We were committed to Shuttle, warts and all, it would *eventually* go through. Now however we aren't so. Remember G H W Bush's "mars program" that didn't do squat. That could be the fate of VSE given an Ares cancellation - could lose it all for a while. Which is why Ares I is so dumb.
Title: RE: DIRECT v2.0
Post by: clongton on 06/01/2007 07:26 PM
Quote
PMN1 - 1/6/2007  3:18 PM

What happens to the attachment points on the ET for the orbitter in the Direct and the Ares V approach - are they removed or are they going to stay there (less the struts) as its not worth removing them?
They go away.
Title: RE: Jupiter-232 1-Launch model?
Post by: Smatcha on 06/02/2007 06:18 AM
Yes, the Jupiter-244 with a two man mission.

Title: Re: Jupiter-232 1-Launch model?
Post by: Danny Dot on 06/02/2007 03:12 PM
Quote
kraisee - 31/5/2007  4:30 PM

snip

In the future though, when the program is fully established, a single launcher solution is possible again.   You need ISRU fuel processing facilities on the Lunar surface, and something DC-X like as a reusable lander/launcher acting as a "Lunar Taxi" to and from Lunar orbit.   At that point you only need a single Heavy Lift Launcher to send a CEV, Crew and Cargo to meet the "Lunar Taxi".

Ross.

Now this would be a slick idea.  I wonder how much mass it would take to set up the mining and processing facilities.  

Danny Deger
Title: Re: Jupiter-232 1-Launch model?
Post by: Smatcha on 06/02/2007 03:56 PM
Quote
Danny Dot - 2/6/2007  8:12 AM

Quote
kraisee - 31/5/2007  4:30 PM

snip

In the future though, when the program is fully established, a single launcher solution is possible again.   You need ISRU fuel processing facilities on the Lunar surface, and something DC-X like as a reusable lander/launcher acting as a "Lunar Taxi" to and from Lunar orbit.   At that point you only need a single Heavy Lift Launcher to send a CEV, Crew and Cargo to meet the "Lunar Taxi".

Ross.

Now this would be a slick idea.  I wonder how much mass it would take to set up the mining and processing facilities.  

Danny Deger

Look at some of the references in our AIAA Space 2006 paper.

http://www.teamvisioninc.com/services-consulting-space-exploration-optimization.htm

Title: Re: Jupiter-232 1-Launch model?
Post by: kraisee on 06/02/2007 06:58 PM
Quote
Danny Dot - 2/6/2007  11:12 AM


Now this would be a slick idea.  I wonder how much mass it would take to set up the mining and processing facilities.

Yeah, that's the big question.   I can imagine landing "mining modules" by Cargo landers courtesy of single HLV flights.   You need to dig the regolith & sort the elements (one module), store & transport them to a more thorough processing facility (a second), purify them at that facility (a third) and make sure they are at the right temperatures for long-term storage (fifth).   You then need some sort of reliable and robust fuelling system for the LV which can cope with Lunar dust and the differing possition of each landing (six).

It certainly is a challenge, but I see many advantages if it can be done.

IMHO, another future update would be an LEO > LLO (or L2) taxi craft, also fuelled from Lunar resources (brought to it by the Lunar lander craft).   It would never land anywhere and simply cycle materials between LEO and LLO.   This has potential benefits by launching all your TLI, LOI, TEI and EOI propellant mass from 1/6th gravity well w/ no drag effects.

An EELV class vehicle could bring crews up to LEO on their own.   A J-120 class vehicle could bring up crew and cargo for transit to the moon.   Rendezvous in LEO and transfer to the Obrital taxi.   At LLO (or L2), transfer to the Lunar Lander taxi and descend.

This profile maximizes Earth launch mass fractions, while sourcing propellant from a (potentially) better gravity well source than Earth.

This sort of infrastruture would allow for far bigger missions to occur, yet with fewer launches with easily achievable LV technology.

The key is you need to make sure you aren't blowing all your annual budget.   Developing and Operating two expensive LV's when one can do the job is a great way to waste money.

Ross.
Title: RE: DIRECT v2.0 - Jupiter-232 1-Launch model?
Post by: kraisee on 06/02/2007 07:10 PM
Quote
SMetch - 2/6/2007  2:18 AM

Yes, the Jupiter-244 with a two man mission.

Actually the J-244 configuration is unnecessary.   The J-231 or J-232 are sufficient for a bare-bones two-man mission profile.   Also the J-244 configuration can not meet ESAS LOC criteria, so the arguments against that would be substantial.

But this option is already off the cards.   "Four people, one week" is the minimum acceptable requirement for Constellation.   Unless we build something in the Nova class (no cash, no will; no chance), that's going to mean two flights.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/02/2007 07:31 PM
Quote
nobodyofconsequence - 1/6/2007  3:20 PM

Quote
PMN1 - 1/6/2007 1:55 PM If there had been more problems and delays with the orbitter part of the system in the late 70's and talk of cancellation, what are the chances of being able to salvage a Direct or an Ares I/V system from the work already done or is it more likley that everything would be cancelled?
The politics were different then. We were committed to Shuttle, warts and all, it would *eventually* go through. Now however we aren't so. Remember G H W Bush's "mars program" that didn't do squat. That could be the fate of VSE given an Ares cancellation - could lose it all for a while. Which is why Ares I is so dumb.

Agreed.   Shuttle was forced through because Apollo was already dead.   The US still needed space access, and STS was the only real game in town.

The same basic thing is happening now, with STS being retired in 2010.   The US, again, needs a replacement.

But the replacement we are gettting first is Ares-I - which is no moon rocket.   There is no particular reason for Congress to support Ares-V as well.    Ares-I fulfills Congress' requirements of workforce retention and US astronauts flying on a home-grown vehicle.

As far as Congress is concerned, both the national pride box and the economics box are checked fully by Ares-I.

Make no mistake, Ares-V is not essential to anyone other than those in the space program who want to go back to the moon.   Congress has no "need" for Ares-V.   NASA does.   The two are not in conflict right now, but we have 12 years to go and changes of political will over that timeframe are innevitable.

All it takes is one of the 7 different Congresses, or one appointee in the Oval Office and we can lose the second vehicle and just be left with the first.

Ares-I as the first vehicle can not enable Lunar Missions - it requires a second "big brother".

Jupiter-120 as the first vehicle *can* support Lunar missions with only the development of an upper stage required.

The choice to change direction away from Ares-I and delete the risk of Ares-V cancellation must be made before long though.

And like I have said before: Jupiter-120 can still pave the way for Ares-V if the money & political will does continue.   But if it doesn't, we dont risk losing the moon.

Griffin has currently chosen a maximum cost "gamble".   We're trying to convince him to switch to a lower cost "sure-bet" instead.   The choice is his.

Ross.
Title: Re: DIRECT v2.0
Post by: rumble on 06/02/2007 07:55 PM
Quote
kraisee - 2/6/2007  2:31 PM

snip

As far as Congress is concerned, both the national pride box and the economics box are checked fully by Ares-I.

snip
uh...  I might agree that as far as CONGRESS is concerned, there's some national pride there, but I tend to think the general public will look at Orion + Ares-I (if that's all we get), and the yawn will be deafening!

It'll be something like, "You mean we tossed out the shuttle (warts & all), and have downgraded from the ability to DO something in orbit to just ferrying people back & forth?  yahoo."

Joe 6-pack doesn't pay attention to most of what's going on, but if the perception is we've traded in the truck for a sub-compact, I don't think you'll get much cheering.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/02/2007 08:42 PM
Quote
rumble - 2/6/2007  1:55 PM
uh...  I might agree that as far as CONGRESS is concerned, there's some national pride there, but I tend to think the general public will look at Orion + Ares-I (if that's all we get), and the yawn will be deafening!

It'll be something like, "You mean we tossed out the shuttle (warts & all), and have downgraded from the ability to DO something in orbit to just ferrying people back & forth?  yahoo."

Joe 6-pack doesn't pay attention to most of what's going on, but if the perception is we've traded in the truck for a sub-compact, I don't think you'll get much cheering.

I agree.

On the other hand, if they hear we've traded the minivan with the DVD player for truck with twice the cargo capacity (J-120) or 4-times the cargo capacity (J-232/231), that might get some attention.

"This sucker can take the equivalent of 5 semi-loads of cargo from 0 to 100 in 3 seconds - straight up".  Yeah, that'll get more attention than, "this can put 6 people in space with the cloths on their backs and a week of food and water".
Title: Re: DIRECT v2.0
Post by: marsavian on 06/02/2007 08:57 PM
yeah Ares I will be boring compared to the Shuttle because it can't carry anything and Ares V will be boring compared to Saturn V because no crew will be on it.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/02/2007 10:31 PM
The loud yawn we hear in response to Ares-I will come smack in the middle of the time NASA is spending billions developing Ares-V.

Is that going to help or hinder things?   I know my opinion.

Ross.
Title: RE: DIRECT v2.0 - Jupiter-232 1-Launch model?
Post by: Smatcha on 06/03/2007 01:36 AM
Quote
kraisee - 2/6/2007  12:10 PM

Quote
SMetch - 2/6/2007  2:18 AM

Yes, the Jupiter-244 with a two man mission.

Actually the J-244 configuration is unnecessary.   The J-231 or J-232 are sufficient for a bare-bones two-man mission profile.   Also the J-244 configuration can not meet ESAS LOC criteria, so the arguments against that would be substantial.

But this option is already off the cards.   "Four people, one week" is the minimum acceptable requirement for Constellation.   Unless we build something in the Nova class (no cash, no will; no chance), that's going to mean two flights.

Ross.
 

LSR of 2xJupiter-244 solves the problem.  Unlike NASA’s current over focus on the Earth ascent portion of LOC the real LOC is based on the complete Earth to Moon and back LOC numbers.  A 2xJupiter-244 puts a lunar Hab down followed by a direct ascent/return capsule sized for four.  This approach would place four people on the Moon for months at a time or two for a lunar sortie of seven days to hook up with the robot rovers with samples gathered over a 1,000 sq mile area over 6 months.

The current LSAM is both too big for a sortie and too small for anything else.  By balancing the architecture we can balance the objectives of VSE.  The multi-faceted Jupiter Family and the 2xHLV approach provides a ton of options.  Options none of us may know about now but will none the less be discovered once we protect the STS base from Mikes hack job.

Options the dysfunctional Areas 1/5 1.5 family will never have.


Title: Re: DIRECT v2.0
Post by: MKremer on 06/03/2007 02:09 AM
Quote
kraisee - 2/6/2007  5:31 PM

The loud yawn we hear in response to Ares-I will come smack in the middle of the time NASA is spending billions developing Ares-V.
I think a lot will depend on how the MSM reporters/editors/producers take it - will it be:
 
"Look how much money NASA has spent and they still can barely make it to the ISS!!"...

or

"The U.S. now has 1/2 of its new Exploration hardware: we can get into orbit, but why can't we get to the moon yet??"

Um, I'm not betting on which it will be.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 06/03/2007 02:16 AM
Stephen,

How far is it from a Jupiter 232 to a 244?  It would appear that the first stage would need to be strengthened somewhat to handle the thrust of the fourth engine, and the second stage would have to be considerably lengthened and strengthened.  That sounds to me like it could be a substantial development project, almost as big as developing the 232 in the first place.  Or is there something that makes developing a 244 when you have a 232 a lot easier?

Also, why four engines on the second stage?  I'm estimating that you're adding about 500,000 pounds to the second stage and the payload; it would seem like a single additional J-2x would be adequate to handle the additional mass.  Or is it a factor of the first stage burning out so soon that you're still fighting gravity losses, and you need the extra thrust to get the delta-V fast enough?
Title: Re: DIRECT v2.0
Post by: WFS on 06/03/2007 03:52 AM
Unless there is an expert in the field on the team I think it is a mistake to try and develop a detailed description of a possible safety system (water, kevlar, boron carbide or other materials as shielding) for the Jupiter 120. Unless you cando the analysis with the same rigor shown in the current Direct proposal you leave youself open to people who want to find fault with your ideas.  

Instead I would suggest you compare the LOM and LOC numbers for the Jupiter and the Ares I, discuss the reasons the the Ares I numbers have a greater range of uncertainty (more new technology means a less certain analysis) and point out that the Jupiter 120 has a considerable mass margin to allow for redundant safety systems is they are needed, while the Ares I is hard pressed to carry the exisitng Orion design.
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/03/2007 05:23 AM
Quote
SolarPowered - 2/6/2007  7:16 PM

Stephen,

How far is it from a Jupiter 232 to a 244?  It would appear that the first stage would need to be strengthened somewhat to handle the thrust of the fourth engine, and the second stage would have to be considerably lengthened and strengthened.  That sounds to me like it could be a substantial development project, almost as big as developing the 232 in the first place.  Or is there something that makes developing a 244 when you have a 232 a lot easier?

Also, why four engines on the second stage?  I'm estimating that you're adding about 500,000 pounds to the second stage and the payload; it would seem like a single additional J-2x would be adequate to handle the additional mass.  Or is it a factor of the first stage burning out so soon that you're still fighting gravity losses, and you need the extra thrust to get the delta-V fast enough?

Good questions, concerning the higher axial loads of a 4 vs 3 engine configuration.

First remember everything going on during an ascent is very dynamic.  The vehicle mass, dynamic pressure, acceleration, velocity, specific performance are all changing.  Some of these changes help you out from a structural load some don’t.

For example the SRB’s carry the bulk of the load above the intertank.  Draining the LOX tank 2x as fast as the current STS lowers the main stages LOX mass so that at SRB separation the LH2 tank doesn’t have as much LOX mass above.  Of coarse missing LOX mass is now replaced with a much heavier upperstage.  The Jupiter-244 would also have a full second stage with an upper stage (1xJ-2x) above it for EOI/EDS.

Again I know the LOC and LOM numbers will go up for the ascent portion of the mission but the reductions in EOR-LOR or LOR-LOR will compensate.  There something nice about leaving the Earth with everything you need to get back.  It’s even nicer when you can leave the Moon anytime to come home.  In the end we have to pick our poison.  If even 1/200 (one LOC every 100 years) keeps us on the Earth we have no business going into to space.

That’s not to say there won’t be any changes in the main tank but since we are staging sooner, due to the four main engines, a higher mass/thrust full second stage (the reason for four engines) is needed to take advantage of this.  The effect on final orbit mass due to the structural mass additions of a lower stage don’t have nearly the impact that they do on say a Jupiter-120 where the main stage goes further into orbit.

One of the key concepts of the Jupiter family is that we should plan for flexibility in the design to allow for say 2x shifts in load levels for key high mass components.  Ideally all we’ll need to change is the machining programs (thin it up for the Jupiter-120 and make it thicker for the Jupiter-254) and we are good to go with a lot of commonality between both the lower and upper stages ranging from the Jupiter-120 to the Jupiter-254.

I think a lot of this will happen in due coarse and when/if needed.  The important thing is we have a family concept that can adjust to the situation.  If we need to get small and only need 2x the best ELV we can do that with the Jupiter-120.  If we need to get big to do a direct/ascent return of a 2-man 7-day sortie mission we can do that to.  If we need to put up to +75mT on the lunar surface 2xJupiter-254 via LOR can do that to.

In comparison the Ares 1/5 1.5 looks like a one trick pony.

Title: Re: DIRECT v2.0
Post by: Smatcha on 06/03/2007 05:44 AM
Quote
WFS - 2/6/2007  8:52 PM

Unless there is an expert in the field on the team I think it is a mistake to try and develop a detailed description of a possible safety system (water, kevlar, boron carbide or other materials as shielding) for the Jupiter 120. Unless you cando the analysis with the same rigor shown in the current Direct proposal you leave youself open to people who want to find fault with your ideas.  

Instead I would suggest you compare the LOM and LOC numbers for the Jupiter and the Ares I, discuss the reasons the the Ares I numbers have a greater range of uncertainty (more new technology means a less certain analysis) and point out that the Jupiter 120 has a considerable mass margin to allow for redundant safety systems is they are needed, while the Ares I is hard pressed to carry the exisitng Orion design.

I agree, if we dump some propellant we can run at even lower operational levels on the engines naturally increasing their safety.  Because the ELVs run at higher operational levels this builds a lot of inherent safety into manned launches of the Jupiter.  We also don’t have a staging event to a new engine/upper stage or require the Orion to do as many burns.

The biggest “problem” is the second SRB but they don’t add much to the LOC numbers based on the 4-Segment numbers NASA claims.  That’s’ why we are using them on the Ares 1  right Scott?  SRB’s good ELV’s bad?

Don’t think of the tank on the Jupiter-120 as half full or half empty think of it as over designed.  Over design is a good thing for safety, right Scott?  How is that whole over design for safety coming on the Stick?  Yet another problem the Stick is that it is going to be pushing all these new unproven systems right out of the box (not safe Scott) just to get the 3rd stage into a weak Orbit (not good Scott).  The third stage is better know as the Orion.

Sorry I had to ask the questions no one is asking them.  Maybe some could give me a good guess as to Scott’s answer.


Title: Re: DIRECT v2.0
Post by: Will on 06/03/2007 01:54 PM
As I understand it, in the baseline figure 11 Direct Architecture, 68 mT of propellant in the EDS is supposed to send a 25 MT Cev, a 38 mT LSAM, a 23 mT EDS and a 4 mT payload adapter to TLI: a total of 90 mT.

This doesn't seem to fit the rocket equation and credible J-2 ISP. Explain, please.

Will
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/03/2007 05:28 PM
Quote
Will - 3/6/2007  6:54 AM

As I understand it, in the baseline figure 11 Direct Architecture, 68 mT of propellant in the EDS is supposed to send a 25 MT Cev, a 38 mT LSAM, a 23 mT EDS and a 4 mT payload adapter to TLI: a total of 90 mT.

This doesn't seem to fit the rocket equation and credible J-2 ISP. Explain, please.

Will

Will in the EOR-LOR option +30mT of fuel is transferred to the EDS.

Title: Re: DIRECT v2.0
Post by: Will on 06/03/2007 05:49 PM
SMetch writes:

"Will in the EOR-LOR option +30mT of fuel is transferred to the EDS."

In EOR-LOr option in figure 11, Jupiter 120 only has 20 mT available for payload in addition to CEV. Not all of that is available for propllant, since mass must be allowed for propellant module, tanks, transfer equipment and rendezvous propellant.

Will


Title: Re: DIRECT v2.0
Post by: Smatcha on 06/04/2007 12:47 AM
Quote
Will - 3/6/2007  10:49 AM

SMetch writes:

"Will in the EOR-LOR option +30mT of fuel is transferred to the EDS."

In EOR-LOr option in figure 11, Jupiter 120 only has 20 mT available for payload in addition to CEV. Not all of that is available for propllant, since mass must be allowed for propellant module, tanks, transfer equipment and rendezvous propellant.

Will



That is with a safety margin 25-30mT might be closer.

See atttached DeltaV calcs.  Note this is a greater TLI than the current approach and we can still up grade to a Jupiter-232 and blow the current plan out of the water at anytime.






Title: Re: DIRECT v2.0
Post by: Smatcha on 06/04/2007 02:59 PM
Quote
Will - 3/6/2007  10:49 AM

SMetch writes:

"Will in the EOR-LOR option +30mT of fuel is transferred to the EDS."

In EOR-LOr option in figure 11, Jupiter 120 only has 20 mT available for payload in addition to CEV. Not all of that is available for propllant, since mass must be allowed for propellant module, tanks, transfer equipment and rendezvous propellant.

Will



Will, another option with more DV margin at a lower ISP assumption.  Note the Jupiter-120 has margin to cover shortfall plus some left over.  Unlike the Ares I and even Ares V for that matter.  The benefits of a 2xHLV Direct STS derivative is that relatively minor upgrades in the first or second launches could cover just about any reasonable short fall.  

In direct contrast any short fall in the Ares 1/5 1.5 plan means a reduction in mission scope and safety, sometimes both.

We will be expanding on this in the paper.

Good catch though all things considered we need to transfer +24mT of fuel to the EDS in order to an equivalent 1.5 plan with a safety margin.  Remember our CEV has a lot more mass than the current 1.5 plan because they use the Orion as 3rd stage to cover the Ares 1 shortfall.  None the less the good news is that we aren’t limited to the 1.5 and there are a number of more efficient approaches we can explore and will in the paper.

Another nice factor is we don’t even need to even know what the best option is right now the Jupiter Family can shrink or grow to cover what the best balance is for the mission/spacecraft elements.

See the mission of the Direct team is to go to moon not to protect the now obviously bad decision of Ares I.  Whether NASA can force the Ares I into some flexible definition of “success” is not the question.  The question is can VSE be successful using the capabilities Ares I will ultimately produce or is something like Direct the best way to go with our inherent ability to produce a significant increase in IMLEO over the 1.5 plan.


Title: RE: DIRECT v2.0
Post by: texas_space on 06/04/2007 03:34 PM
If there's anything that will kill beyond-LEO manned spaceflight, then this is it.  A similar number was derived for SEI in the early 90s and that ended up being dead on arrival.  All the more reason for a solution other than Ares 1/5 family.

From FlightGlobal.com:
http://www.flightglobal.com/articles/2007/06/05/214397/moon-and-mars-programme-costs-estimated-at-500bn.html
Title: Re: DIRECT v2.0
Post by: Will on 06/04/2007 04:28 PM
Note that NASA groundrules require the EDS to send a useful payload 65.5 mT to TLI, plus a 10% payload margin. Jupiter 130+232 only does 63, even assuming massless propellant tanks on 131, no propellant required for rendezvous, etc.

Will
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/04/2007 05:27 PM
Quote
Will - 4/6/2007  9:28 AM

Note that NASA groundrules require the EDS to send a useful payload 65.5 mT to TLI, plus a 10% payload margin. Jupiter 130+232 only does 63, even assuming massless propellant tanks on 131, no propellant required for rendezvous, etc.

Will

Okay, starting with the NASA “groundrules” which are different than normal groundrules in that NASA “groundrules” will change depending on what the Ares 1/5 1.5 plan that Mike/Scott came in with actually achieves.

NASA ground rules 66.5x 1.1 = 73.15mT

Looking at the attached chart for the Ares 1/5 1.5 plan using the best public info we have right now.  We are above their actual numbers at 63mT vs NASA 59mT.

Concerning public info NASA admitted at AIAA 2006 they have negative margins on their paper rockets as Kayla indicated and Jim has pointed out would kill current programs out of JPL requiring a complete reset of the requirements/mission.  Note JPL is the only organization to actually leave LEO for exploration for sometime.  That team has been there and been doing that for some time.

Our plan puts a net of 63mT on a TLI.  Converting some of the Jupiter-120 margin to more EDS fuel we can achieve this NASA 73mT “groundrule”.  Needed for global access anytime return.  If things get really bad we can always pull out a Jupiter-232 and do a dual EDS or save some LSAM mass by having the Orion EDS to do the LOA.  There are 10 good scenarios we could fall back on at least.

Again back to the NASA “groundrule” because the Ares 1/5 1.5 plan is coming up short they changed the mission to the Lunar poles (Ie little ISS on the crater rim) to help them on the DeltaV they need for plane change.  The problem is the Earth departure is now messed up but it’s really getting hard to keep up with all of NASA’s ever shifting “groundrules”.  Especially since they have yet to produce a mass statement for the Earth to the Moon and back like we are doing.

So that individuals such as yourself can perform the necessary second pair of eyes/minds needed to make sure we aren’t out to lunch.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/04/2007 05:30 PM
Will, agreed.   The J-120/23n combination is very much "borderline" in terms of mission performance.

We've been using it simply as an option for a first generation "entry level" mission, while we are still finding our feet, keeping lunar Crew launches on the slightly safer J-120 configuration.   It has always been a "stepping stone" used to get us to the 2xJ-23n architecture eventually.

The more I think about it though, the more I am thinking about deleting that "low end" option and diving straight into the more powerful 2x J-232 architecture and getting the full performance from day 1.

Ross.
Title: Re: DIRECT v2.0
Post by: marsavian on 06/04/2007 05:35 PM
Quote
kraisee - 30/5/2007  10:36 PM

Quote
mike robel - 30/5/2007  11:17 PM

I should think it would be better to integrate this ballistic shield with the main CSM structure so as to also provide radiation shielding.  To loft  the thing with no purpose but ballistic protection in the unlikely event of a booster explosion, not specifically aimed at the CM seems somewhat wasteful to me.  As opposed to a high energy long rod KE penetrator aimed at a tank.  Enough KE can always be found to penetrate any armor, which is what a ballistic shield is anyway.  A somewhat less dense ceramic mix or mixture of Kevlar, Gortex, and other high density fabrics in addition to ceramics may be all that is necessary for an effective shield for a relatively low energy event  - not like a DU penetrator aimed at the target with velocities approaching 2 miles per second.

Agreed.   I think there's a lot of research which could be done in this area to protect crews.   the Boron Carbide looks like a fairly good radiation shielding in addition to it's ballistic properties, but a kevlar/carbon-fibre/Gortex also appear to be of great value too.   The most effective solution may well turn out to be a multi-layer composite material, with perhaps Silicone Nitride in one layer, together with a layer of something like Kevlar, and perhaps even a third layer of Silicone Nitride.   I'm not sure what order to place the different materials myself, but the overlapping performance characteristics of a multi-layer approach offers a lot of potential to this concept.

The DIRECT team is not really set-up to be able to research the particular materials ourselves, so we are researching a number of military sources for useful information currently to include in an addendum to our core report.   Data exists for all the armour types in use by the military today, and I'm sure the manufacturers of such things would be interested in a regular contract from NASA for their wares.

It is possible that we will take the approach of suggesting half a dozen different materials & composites which should be "trade studied" and then budget a reasonable mass allocation for such a system into our calculations, based on masses utilised in similar real-world applications.

This will allow us to press on without getting bogged down in the precise formulation of what the shield is actually made from.   We can present a series of basic safety numbers and costs based on a range of different materials, and then leave the rest to a deeper trade study later.

Ross.

You can add Kevlar to your already used in Space list ;-). Doesn't look as if any of them will be a problem. Just remember Silicon Nitride is non-porous and would keep out hot liquids too if it retained its structural integrity which is why it should be your last line of defence IMO.*

 
http://www.space.com/news/ft_070604_aging_orbiters.html

Shuttle orbiters are equipped with 24 helium and nitrogen gas tanks that pressurize the shuttle's main propulsion system, orbital maneuvering engines and nose-and-tail steering thrusters.

The spherical tanks provide pressure needed to push rocket propellants into shuttle engines and thrusters at very specific rates required to keep the spaceship on its proper course. Some of the propellants are highly volatile and ignite on contact.

Ranging in diameter from 19 to 40 inches, the tanks have lightweight titanium or steel shells wrapped with the same type of fabric used to make bulletproof vests -- Kevlar -- or carbon graphite. They hold helium and nitrogen gas at extremely high pressures (up to 4,600 pounds per square inch) and are extraordinarily dangerous.

"You certainly wouldn't want a 4-foot-diameter helium bottle that's pressurized to about 4,000 psia to burst on you," Hale said. "That would be a bad thing."

A tank rupture on the ground could lead to a fire or explosion that could injure or kill workers in the launch pad area. A failure in flight could lead to the loss of a shuttle and the astronauts inside.


*
http://www.ignitersdirect.com/comparisons.htm


Longer usable life
Silicon Nitride does not react in any way like its silicon carbide counterpart. Unlike Silicon Carbide which has a porous construction, Silicon Nitride is non porous and does not oxidise with age. It is widely known that Silicon Carbide igniter elements must not be touched as the greases deposited produces 'HOT SPOTS' shortening the life of the igniter. Care must be taken not to allow cleaning agents to come into contact with Silicon Carbide igniter element. Silicon Nitride igniter’s display none of these problems, holding with the greasiest of hands will not do any harm whatsoever. Silicon Nitride igniter elements can be cleaned with even the most toughest of cleaners and can withstand strong alkali’s and acids.

Greater Physical Strength
The Silicon Nitride material is used by the largest bearing companies in the world. It is the only material to be approved for use in ball and roller bearings in NASA's space shuttle main engine liquid oxygen and liquid hydrogen turbopumps - one of the most severe applications ever developed for rolling element bearings. It also helped the Thrust SSC car achieve its record-breaking Mach 1+ land speed run by allowing the wheel bearings to operate reliably at over 480,000 dN.

Furnace, Water Heater/ Boiler
The Igniter is a critical part of any appliance ignition system. Fitting the Glo-Stix ™ will ensure maximum performance and efficiency is maintained.

Typical characteristics of Silicon Nitride include:
High strength over a wide temperature range
High fracture toughness
High hardness
Outstanding wear resistance, both impingement and frictional modes
Good thermal shock resistance
Good chemical resistance

Silicon Nitride has totally different physical and chemical characteristics than Silicon Carbide. It is a robust new technology with low energy consumption.

 




Title: Re: DIRECT v2.0
Post by: marsavian on 06/04/2007 05:43 PM
and Boron Carbide too ...

Nuclear Reactors for Space

http://www.world-nuclear.org/info/inf82.html

Heatpipe Power System (HPS) reactors are compact fast reactors producing up to 100 kWe for about ten years to power a spacecraft or planetary surface vehicle. They have been developed since 1994 at the Los Alamos National Laboratory as a robust and low technical risk system with an emphasis on high reliability and safety. They employ heatpipes to transfer energy from the reactor core to make electricity using Stirling or Brayton cycle converters.

Energy from fission is conducted from the fuel pins to the heatpipes filled with sodium vapour which carry it to the heat exchangers and thence in hot gas to the power conversion systems to make electricity. The gas is 72% helium and 28% xenon.

The reactor itself contains a number of heatpipe modules with the fuel. Each module has its central heatpipe with rhenium-clad fuel sleeves arranged around it. They are the same diameter and contain 97% enriched uranium nitride fuel, all within the cladding of the module. The modules form a compact hexagonal core.

Control is by six stainless steel clad beryllium drums each 11 or 13 cm diameter with boron carbide forming a 120 degree arc on each. The drums fit within the six sections of the beryllium radial neutron reflector surrounding the core, and rotate to effect control, moving the boron carbide in or out.

Shielding is dependent on the mission or application, but lithium hydride in stainless steel cans is the main neutron shielding.


Title: Re: DIRECT v2.0
Post by: marsavian on 06/04/2007 05:49 PM
Quote
kraisee - 4/6/2007  12:30 PM

Will, agreed.   The J-120/23n combination is very much "borderline" in terms of mission performance.

We've been using it simply as an option for a first generation "entry level" mission, while we are still finding our feet, keeping lunar Crew launches on the slightly safer J-120 configuration.   It has always been a "stepping stone" used to get us to the 2xJ-23n architecture eventually.

The more I think about it though, the more I am thinking about deleting that "low end" option and diving straight into the more powerful 2x J-232 architecture and getting the full performance from day 1.

Ross.

Absolutely. One true base launcher giving you all the performance you need. You are going to get harangued for it not being simple anyway so go the whole way and do it once only and get your Moon mission even earlier which after all is the first end destination of VSE ;-).
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/04/2007 05:55 PM
I thought the main purposes of the J-120 were to do near-term testing and, later to get Orion to ISS while the EDS was being developed for the J-232.
Title: Re: DIRECT v2.0
Post by: clongton on 06/04/2007 06:01 PM
Quote
Lee Jay - 4/6/2007  1:55 PM

I thought the main purposes of the J-120 were to do near-term testing and, later to get Orion to ISS while the EDS was being developed for the J-232.
Correct. But in the interest of "apples to apples" it was thought to be useful to compare the ERO-LOR architecture that NASA is stuck with. Remember, NASA can't do anything except EOR-LOR with the limited resources it plans on fielding.

EOR-LOR is not the baseline architecture for Direct. That's far to inefficient for a robust lunar program, that the Direct architecture makes possible, but it is the best that NASA can do. We were trying to dumb-down the approach a little to show the equivilant.
Title: Re: DIRECT v2.0
Post by: marsavian on 06/04/2007 06:08 PM
Quote
kraisee - 4/6/2007  12:30 PM

Will, agreed.   The J-120/23n combination is very much "borderline" in terms of mission performance.

We've been using it simply as an option for a first generation "entry level" mission, while we are still finding our feet, keeping lunar Crew launches on the slightly safer J-120 configuration.   It has always been a "stepping stone" used to get us to the 2xJ-23n architecture eventually.

The more I think about it though, the more I am thinking about deleting that "low end" option and diving straight into the more powerful 2x J-232 architecture and getting the full performance from day 1.

Ross.

OTOH the politicians want their early ISS access. Perhaps an ISS only Jupiter-120 is the answer with VSE carried out solely by Jupiter-232s.
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/04/2007 06:16 PM
Quote
marsavian - 4/6/2007  11:08 AM

Quote
kraisee - 4/6/2007  12:30 PM

Will, agreed.   The J-120/23n combination is very much "borderline" in terms of mission performance.

We've been using it simply as an option for a first generation "entry level" mission, while we are still finding our feet, keeping lunar Crew launches on the slightly safer J-120 configuration.   It has always been a "stepping stone" used to get us to the 2xJ-23n architecture eventually.

The more I think about it though, the more I am thinking about deleting that "low end" option and diving straight into the more powerful 2x J-232 architecture and getting the full performance from day 1.

Ross.

OTOH the politicians want their early ISS access. Perhaps an ISS only Jupiter-120 is the answer with VSE carried out solely by Jupiter-232s.

That’s the approach that seems to be forming.  It puts a number of important yet expensive technologies such as the J2x and Advanced Upper stage until after the Orion/Jupiter-120 is flying.  Right now we have our hands full just getting an ISS Orion + STS retargeted at VSE’s long term objectives.  All while given us a true Apollo+ program later.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/04/2007 06:17 PM
Quote
clongton - 4/6/2007  12:01 PM

Quote
Lee Jay - 4/6/2007  1:55 PM

I thought the main purposes of the J-120 were to do near-term testing and, later to get Orion to ISS while the EDS was being developed for the J-232.
Correct. But in the interest of "apples to apples" it was thought to be useful to compare the ERO-LOR architecture that NASA is stuck with. Remember, NASA can't do any except EOR-LOR with the limited resources it plans on fielding.

EOR-LOR is not the baseline architecture for Direct. That's far to inefficient for a robust lunar program, but it is the best that NASA can do. We were trying to dumb-down to show an equivilant.

Just thinking out loud here, but if the J-120/J-232 lunar option is actually inferior to the Ares-I/Ares V lunar option in some performance fashion, then I'd probably delete the comparison and instead focus on the J-120 as a near-term STS replacement for ISS and a stepping stone to the J-232 - one that doesn't require further development of the core and support hardware like Ares V does.

Lee Jay
Title: Re: DIRECT v2.0
Post by: clongton on 06/04/2007 06:43 PM
Quote
Lee Jay - 4/6/2007  2:17 PM

Quote
clongton - 4/6/2007  12:01 PM

Quote
Lee Jay - 4/6/2007  1:55 PM

I thought the main purposes of the J-120 were to do near-term testing and, later to get Orion to ISS while the EDS was being developed for the J-232.
Correct. But in the interest of "apples to apples" it was thought to be useful to compare the ERO-LOR architecture that NASA is stuck with. Remember, NASA can't do any except EOR-LOR with the limited resources it plans on fielding.

EOR-LOR is not the baseline architecture for Direct. That's far to inefficient for a robust lunar program, but it is the best that NASA can do. We were trying to dumb-down to show an equivilant.

Just thinking out loud here, but if the J-120/J-232 lunar option is actually inferior to the Ares-I/Ares V lunar option in some performance fashion, then I'd probably delete the comparison and instead focus on the J-120 as a near-term STS replacement for ISS and a stepping stone to the J-232 - one that doesn't require further development of the core and support hardware like Ares V does. Lee Jay
It's not inferior, just difficult to lower the capabilities. Kinda like reaching the point of diminishing returns, only going the other way. Plus, even if it were (which it is not) it would still have all the political advantages going for it that Ares-I/V can't provide.

But you're right. Creating that kind of a comparison may not be worth the effort. It's sort of like trying to prove that a lotus elan is better than a vw beatle.  :)
The more stuff you remove from its performance, the harder it gets to drive.
Title: Re: DIRECT v2.0
Post by: Will on 06/04/2007 06:46 PM
What sort of performance would you get from Jupiter 121 or 131, in which the upper stage is a CEV SM-based tug that fires suborbitally to put the payload into orbit? Thrust/weight would be poor, but I would think you'd gain a lot by not carrying the heavy RS-68 stage all the way to orbit. It could be ready relatively early, and the pressure fed storable engine should be more reliable than the J-2.

Will
Title: Re: DIRECT v2.0
Post by: Will on 06/04/2007 06:51 PM
SMetch writes:

"Looking at the attached chart for the Ares 1/5 1.5 plan using the best public info we have right now."

This is not legible on my screen.

Will
Title: Re: DIRECT v2.0
Post by: clongton on 06/04/2007 06:57 PM
Quote
Will - 4/6/2007  2:46 PM

What sort of performance would you get from Jupiter 121 or 131, in which the upper stage is a CEV SM-based tug that fires suborbitally to put the payload into orbit? Thrust/weight would be poor, but I would think you'd gain a lot by not carrying the heavy RS-68 stage all the way to orbit. It could be ready relatively early, and the pressure fed storable engine should be more reliable than the J-2.
Will, we thought about that but decided that for Shuttle transition, we really wanted to ignite all flight engines on the ground, like Shuttle. That makes for a much safer ascent to orbit until we have gained experience later with the J-2XD upper stage engine. We are confident that there will be no safety concern with the J-2XD, but we would prefer to put flight experience under our belts first, unlike Ares-I, which requires the upper stage ignition at altitude. Eventually, for the lunar missions, we will as well, but by then, there will be lots of flight history behind it before we commit a human crew to it. Ares-I commits to an upper stage ignition event from the very beginning, with no previous flight history. We would rather not commit the lives of a crew to the hoped-for ignition, half way to space, of a brand new engine until we have some flight history with it.
Title: Re: DIRECT v2.0
Post by: Will on 06/04/2007 08:00 PM
Quote
clongton - 4/6/2007  1:57 PM

 We would rather not commit the lives of a crew to the hoped-for ignition, half way to space, of a brand new engine until we have some flight history with it.


What do you need a new engine for? What's wrong with the Shuttle OME?

Will
Title: Re: DIRECT v2.0
Post by: Marsman on 06/04/2007 08:11 PM
The OME does not have enough thrust for this application.
Title: Re: DIRECT v2.0
Post by: Danny Dot on 06/04/2007 08:42 PM
Quote
clongton - 4/6/2007  1:57 PM

Quote
Will - 4/6/2007  2:46 PM

What sort of performance would you get from Jupiter 121 or 131, in which the upper stage is a CEV SM-based tug that fires suborbitally to put the payload into orbit? Thrust/weight would be poor, but I would think you'd gain a lot by not carrying the heavy RS-68 stage all the way to orbit. It could be ready relatively early, and the pressure fed storable engine should be more reliable than the J-2.
Will, we thought about that but decided that for Shuttle transition, we really wanted to ignite all flight engines on the ground, like Shuttle. That makes for a much safer ascent to orbit until we have gained experience later with the J-2XD upper stage engine. We are confident that there will be no safety concern with the J-2XD, but we would prefer to put flight experience under our belts first, unlike Ares-I, which requires the upper stage ignition at altitude. Eventually, for the lunar missions, we will as well, but by then, there will be lots of flight history behind it before we commit a human crew to it. Ares-I commits to an upper stage ignition event from the very beginning, with no previous flight history. We would rather not commit the lives of a crew to the hoped-for ignition, half way to space, of a brand new engine until we have some flight history with it.

If the upper stage fails to ignite, the crew will do an abort.  

Danny Deger
Title: Re: DIRECT v2.0
Post by: clongton on 06/04/2007 08:49 PM
Quote
Danny Dot - 4/6/2007  4:42 PM

Quote
clongton - 4/6/2007  1:57 PM

Quote
Will - 4/6/2007  2:46 PM

What sort of performance would you get from Jupiter 121 or 131, in which the upper stage is a CEV SM-based tug that fires suborbitally to put the payload into orbit? Thrust/weight would be poor, but I would think you'd gain a lot by not carrying the heavy RS-68 stage all the way to orbit. It could be ready relatively early, and the pressure fed storable engine should be more reliable than the J-2.
Will, we thought about that but decided that for Shuttle transition, we really wanted to ignite all flight engines on the ground, like Shuttle. That makes for a much safer ascent to orbit until we have gained experience later with the J-2XD upper stage engine. We are confident that there will be no safety concern with the J-2XD, but we would prefer to put flight experience under our belts first, unlike Ares-I, which requires the upper stage ignition at altitude. Eventually, for the lunar missions, we will as well, but by then, there will be lots of flight history behind it before we commit a human crew to it. Ares-I commits to an upper stage ignition event from the very beginning, with no previous flight history. We would rather not commit the lives of a crew to the hoped-for ignition, half way to space, of a brand new engine until we have some flight history with it.

If the upper stage fails to ignite, the crew will do an abort.  
Obviously, but that's not the point.
The fewer stanging events you MUST complete during the ascent, the safer the ascent is.
We have only flown Shuttle for more than 30 years. We're trying out something new. There is NO NEED to stage the launch vehicle, so why do it? Why make the ride to orbit more complex than it needs to be? Doesn't make any sense.
Title: Re: DIRECT v2.0
Post by: Marsman on 06/04/2007 09:28 PM
Plus, the aborts are inherently dangerous. Why subject the crew to such an extreme event when it can be avoided?
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/04/2007 11:19 PM
Quote
Marsman - 4/6/2007  2:28 PM

Plus, the aborts are inherently dangerous. Why subject the crew to such an extreme event when it can be avoided?

Mission Abort – Definition:

A process of attempted suicide in order to avoid certain death. :)


Title: Re: DIRECT v2.0
Post by: Will on 06/05/2007 12:26 AM
Quote
clongton - 4/6/2007  1:57 PM

 We are confident that there will be no safety concern with the J-2XD, but we would prefer to put flight experience under our belts first, unlike Ares-I, which requires the upper stage ignition at altitude. Eventually, for the lunar missions, we will as well, but by then, there will be lots of flight history behind it before we commit a human crew to it. Ares-I commits to an upper stage ignition event from the very beginning, with no previous flight history. We would rather not commit the lives of a crew to the hoped-for ignition, half way to space, of a brand new engine until we have some flight history with it.


However, the report also mentions an unmanned payload capacity for the Jupiter 120. The core stage and service module would both be ready for flight before the EDS, yes?. If the service module as upper stage increased unmanned payload to LEO, wouldn't that be positive information to present?

Will
Title: Re: DIRECT v2.0
Post by: kraisee on 06/05/2007 05:03 AM
The SM could certainly be used in the same way as it is on Ares-I - as an extra stage, but doing so reduces the LOC/LOM numbers drastically - LOM for Cargo only missions.

While NASA claims an LOC of around 1:2000 for Ares-I, that is only an assessment of the first two stages - and does NOT include the risk factors of using the Orion's Service Module as a third stage completing the ascent.

Factoring this additional 'stage' in to the full assessment reduces the full LOC numbers for *ascent to insertion* considerably.   My own estimate (uncorroborated,  I freely admit) is that including the staging and air-starting of the OME engine during ascent is equivalent to dropping LOM by about 50 points, and dropping LOC by about 300 points.   While Ares-I itself might be 1:2000 in NASA's opinion - the full vehicle placing an Orion into an actual orbit is more like 1:1700.   This makes J-120's 1:1400 look quite acceptable for *completed ascent*.

The J-120 has sufficient performance to placing over 48mT of cargo into insertion orbit without using a third stage - which is inherently safer.

If you did wish to have more payload performance than that, and you accept the additional risks associated with making a CEV variant perform part of the ascent (quite possible), all the payload mass will have to be aboard the CEV (CM or SM) when it separates from the LV, ignites and performs the final ascent burn.   It could not be in a separate module, because there isn't any available time during an ascent to separate, turn around, dock with the module, extract it, turn back around again and complete the ascent.   So it must be within the final module when it separates from the LV.

Such a performance hike is only moderate.   A quick "back of the envelope" calculation indicates that only about 3mT of improvement is possible doing this, but it costs ~300 points of the final LOC for the full ascent.   This extra performance has become essential for Ares-I though, due to its inherent low performance.   Be aware that Ares-I is actually only an 18.1mT to 30x100nm, 28.5deg launcher system without the third stage - which is well below current EELV performance. This performance hike is not really worth considering for a launcher already capable of 48mT performance.

So theoretically, a CEV with extra propellant tanks could use this technique - but a CEV bringing up extra cargo separately could not.   This sort of ambiguity, where sometimes it is possible, and other time it is not, is the sort of thing which we're steering deliberately away from - so as to keep the waters less muddy.


But the Jupiter-120 is primarily designed in order to get us a J-232 configuration for supporting Lunar missions later.   That is the key to the entire plan - the first vehicle is the same one used for all the missions.    This completely removes the need for never-ending political & financial support for a second LV development program.


J-120 also offers a number of benefits in its own right.   It can be made available in a very acceptable time frame.   It has a very acceptable LOM/LOC through using the standard and proven 4-seg SRB's, and by reducing the number of MPS elements to two from three (SSME), and ground lighting all the engines.   It has extremely reasonable costs in terms of disposable engines and tankage structures for its performance.

And, as you say, such performance offers a great test-bed LV for testing of hardware prior to all the hardware being fully operational.

With all these under its belt, a J-120 is certainly more than sufficient for any LEO mission I can currently think of.

As you indicate, a J-120 could easily launch CEV's or test-LSAM's to LEO for test flights (unmanned or manned) before all the hardware is fully completed.

But J-232 is what we are really after - enabling Lunar missions.   J-120 only requires the EDS to enable those Lunar missions.   It does not require a whole extra LV to be developed - and that makes reduces the cash requirements for the whole program.   This means that political/financial strangling is protected against over the next 12 years.   And if cash *is* still available, it can still be used in a variety of ways - speeding up development of other elements, or still building Ares-V - whatever is a priority at that time in the future.

Here are the possible Lunar IMLEO mass performance combinations:

(CLV / CaLV)
Ares-I / Ares-I: No missions possible
Ares-I / Ares-V (EOR): ~175mT *
Jupiter-120 / Jupiter-232 (EOR): ~170mT
Jupiter-232 / Jupiter-232 (EOR): ~235mT
Jupiter-232 / Jupiter-232 (LOR): ~260mT
Jupiter-120 / Ares-V (EOR): ~200mT *
Jupiter-232 / Ares-V (EOR): ~265mT *
Jupiter-232 / Ares-V (LOR): ~285mT *

* - only possible with 2 different successful LV development programs

Ross.
Title: RE: DIRECT v2.0
Post by: renclod on 06/05/2007 12:38 PM
SMetch
Quote
- 1/6/2007  6:45 PM

Jim
Quote
- 1/6/2007  7:53 AM

renclod
Quote
- 31/5/2007  11:18 AM
spacelogistics.mit.edu/pdf/Shull_IAC2006.pdf
The best 2-launch option ... 87mT + 70mT to LEO ... The reduced size Ares V- LVs were modeled as a 4 segment solid rocket booster (SRB) instead of a 5 segment used in the 1.5-launch specification

plus a 1.5-launch specification core stage

Ross and Smetch, why aren't you jumping all over this. Isn't it independent confirmation of the 2 launch scenario?
Jim, we are expanding significantly on this important subject in the AIAA paper.  ...
In the MIT paper, both the 2-launch option and the 1-launch equivalent option are considering the 10 m dia core stage (if I understand correctly).

Direct-2/Jupiter retains the 8 m dia STS hidrogen tank, and this is a big issue.
A plus, if you hope to fly Constellation sooner.

A minus for the Moon/Mars/Asteroids out-years when you might wish you went with a larger core stage from the beginning.
IMHO

Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/05/2007 01:14 PM
Quote
kraisee - 4/6/2007  11:03 PM
The J-120 has sufficient performance to placing over 48mT of cargo into insertion orbit without using a third stage - which is inherently safer.

Just a quick question about this.

The STS is sort of a J-120 - a cryo stage with roughly equivalent thrust and 2 4-segment SRBs, no upper stage.  Yet, the STS manages on the order of 125mT to insertion orbit (including the orbiter, of course).  Is this just because the SSMEs are more efficient?

Lee Jay
Title: RE: DIRECT v2.0
Post by: clongton on 06/05/2007 01:30 PM
Quote
renclod - 5/6/2007  8:38 AM

SMetch
Quote
- 1/6/2007  6:45 PM

Jim
Quote
- 1/6/2007  7:53 AM

renclod
Quote
- 31/5/2007  11:18 AM
spacelogistics.mit.edu/pdf/Shull_IAC2006.pdf
The best 2-launch option ... 87mT + 70mT to LEO ... The reduced size Ares V- LVs were modeled as a 4 segment solid rocket booster (SRB) instead of a 5 segment used in the 1.5-launch specification

plus a 1.5-launch specification core stage

Ross and Smetch, why aren't you jumping all over this. Isn't it independent confirmation of the 2 launch scenario?
Jim, we are expanding significantly on this important subject in the AIAA paper.  ...
In the MIT paper, both the 2-launch option and the 1-launch equivalent option are considering the 10 m dia core stage (if I understand correctly).

Direct-2/Jupiter retains the 8 m dia STS hidrogen tank, and this is a big issue.
A plus, if you hope to fly Constellation sooner.

A minus for the Moon/Mars/Asteroids out-years when you might wish you went with a larger core stage from the beginning.
IMHO
The fairing is essentially just volume. The Jupiter’s 8.4m core can easily accommodate a 10m fairing.
Title: Re: DIRECT v2.0
Post by: Will on 06/05/2007 01:37 PM
Quote
kraisee - 4/6/2007  12:03 AM

The SM could certainly be used in the same way as it is on Ares-I - as an extra stage, but doing so reduces the LOC/LOM numbers drastically - LOM for Cargo only missions.

While NASA claims an LOC of around 1:2000 for Ares-I, that is only an assessment of the first two stages - and does NOT include the risk factors of using the Orion's Service Module as a third stage completing the ascent.

Factoring this additional 'stage' in to the full assessment reduces the full LOC numbers for *ascent to insertion* considerably.   My own estimate (uncorroborated,  I freely admit) is that including the staging and air-starting of the OME engine during ascent is equivalent to dropping LOM by about 50 points, and dropping LOC by about 300 points.   While Ares-I itself might be 1:2000 in NASA's opinion - the full vehicle placing an Orion into an actual orbit is more like 1:1700.  

Ross.

Firing the Orion engine on ascent doesn't add a staging event: Orion needs to separate in any case.

It occurs to me that a Titan second stage would make an interesting interim upper stage for a Jupiter 131: it's in the right ballpark for thrust and mass and the stage is very reliable and has been man-rated in the past.

Are any of those still in mothballs or have they been scrapped?

If it was my program I'd go straight to the 130 rather than the 120. The performance hit is slight, you'd have better engine out capability, and flight experience would be more applicable to the 23n.

Will
Title: Re: DIRECT v2.0
Post by: clongton on 06/05/2007 01:50 PM
Quote
Will - 5/6/2007  9:37 AM

Quote
kraisee - 4/6/2007  12:03 AM

The SM could certainly be used in the same way as it is on Ares-I - as an extra stage, but doing so reduces the LOC/LOM numbers drastically - LOM for Cargo only missions.

While NASA claims an LOC of around 1:2000 for Ares-I, that is only an assessment of the first two stages - and does NOT include the risk factors of using the Orion's Service Module as a third stage completing the ascent.

Factoring this additional 'stage' in to the full assessment reduces the full LOC numbers for *ascent to insertion* considerably.   My own estimate (uncorroborated,  I freely admit) is that including the staging and air-starting of the OME engine during ascent is equivalent to dropping LOM by about 50 points, and dropping LOC by about 300 points.   While Ares-I itself might be 1:2000 in NASA's opinion - the full vehicle placing an Orion into an actual orbit is more like 1:1700.  

Ross.

Firing the Orion engine on ascent doesn't add a staging event: Orion needs to separate in any case.
Firing the Orion engine on ascent absolutely is a staging event because the spacecraft cannot achieve orbit without it. At the point of separation from Ares, Orion is in a SUBORBITAL trajectory, no different than what SpaceShip One did.

Shuttle fires the OMS engines to achieve orbit, not because it has to, but because that's a decision regarding ET disposal, not orbital insertion. Shuttle can achieve orbit without that, but then there would be the problem of the ET being in orbit instead of being disposed of in the ocean.

Orion, on the other hand, cannot be inserted into orbit by the Ares-I. Orion's service module engine has to burn, as a stage event, to achieve orbital velocity because the Ares launch vehicle is incapable of inserting it into orbit. Firing Orion’s engines imparts a huge velocity change to the spacecraft to enable reaching orbit. The Ares-I can’t put Orion into orbit. Orion has to do that itself. That’s the difference, and that is what makes it a stage event. That makes the Orion/Ares stack a 3 stage vehicle.

When flying on the Jupiter however, it becomes an identical situation as Shuttle. Orion will fire its engine to complete the orbital insertion, not because it has to, but to allow the ET to self-dispose, like Shuttle. In this case, Orion’s engine burn is not a stage event because it is not required. The core could easily insert Orion all by itself, but then we’d need to dispose of the core.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/05/2007 05:57 PM
Separation during the ascent phase of a flight, with a very precise engine firing immediately following the separation, is a considerably more difficult proposition than simply separating shortly after inserting into a stable insertion orbit.

The LOM and LOC risks are higher for "staging" events such as the Orion ascent phase, compared to far more benign "payload deployment" events such as we're planning on all Jupiter flights.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/05/2007 06:14 PM
Quote
Lee Jay - 5/6/2007  9:14 AM

Just a quick question about this.

The STS is sort of a J-120 - a cryo stage with roughly equivalent thrust and 2 4-segment SRBs, no upper stage.  Yet, the STS manages on the order of 125mT to insertion orbit (including the orbiter, of course).  Is this just because the SSMEs are more efficient?

Lee, partially, yes.   The switch from 453s Isp SSME's to 409s Isp RS-68's does impact performance noticeably.   That's precisely why v1 of DIRECT was attempting to get the most out of the RS-68 as possible.

But there is also the fact that the Core is actually optimized for a different configuration of launcher - the J-232.   The Common Core is considerably stronger (thus heavier) than it needs to be for just J-120 flights, because it is actually designed to fly with 100+ tons of payload and a fully fuelled EDS on top, not just a CEV & 25 tons of cargo.

Even though the Core is actually sub-optimal for the J-120 configuration, it still offers twice the payload performance of any EELV or Ares-I, so would still be extremely effective.   We consider it a very fair trade-off indeed (BTW, all structure margins for the Core are over 2.1 for the J-120 configuration vs. 1.4 for Ares-I and 1.25 for EELV, which positively affects LOC/LOM).

We could optimize Cores just for J-120, and increase performance by about 10mT per flight, but that would really require a second production line at Michoud - but that is one of the specific cost reductions we have all-along been trying to delete from the current Ares plans.   DIRECT is all about one launcher performing all the roles instead of two.

BTW, I saw someone (you?) suggest a J-130 configuration.   I have run this configuration a number of different ways, and the bottom line is it doesn't work well.   The three main engines guzzle all the fuel too fast and the rocket doesn't reach orbital speeds with anything approaching a reasonable payload - about 24mT.   It also suffers from very high max-Q dynamic pressures & dangerously high g-forces unless you throttling them right down and also turn one engine off for about the last few minutes of the flight.

Jupiter-120 already has engine-out capability from about T+45s onwards with just the regular two engines.   A third engine won't change this much, but kills performance, costs more and detracts from safety.
Title: RE: DIRECT v2.0
Post by: kraisee on 06/05/2007 06:35 PM
Quote
renclod - 5/6/2007  8:38 AM

A minus for the Moon/Mars/Asteroids out-years when you might wish you went with a larger core stage from the beginning.
IMHO

Yes, there is a slight performance loss in some of these situations.   But you should really be thinking of Jupiter as the replacement to Ares-I, not a replacement for Ares-V.

We can still have Ares-V with Jupiter as the first vehicle.   Jupiter actually costs less to make than Ares-I.

But Jupiter protects the program if the second vehicle is cancelled for any reason over the next 12 years.   Jupiter still allows us to mount exploration missions even without Ares-V.   Ares-I can not do so without Ares-V.   So from a program risk perspective, which makes more sense?

But Ares-V is still not a bad "big brother" to Jupiter.   If Ares-I/V were a "1.5 solution", then Jupiter-120/Ares-V must be at least a "1.8 solution"! ;)

Alternatively, assuming Ares-V is not built, and only the single Jupiter were, for half the cost of Ares-I and Ares-V together, you save tens of billions of dollars in full-wrap development costs.  You save even more in the lower yearly running costs of one program vs. two: We have data in-hand which shows DIRECT's architecture saves more than $2 billion every single operational year compared to operating both Ares-I and Ares-V concurrently.

Couldn't these billions saved in development & operations go a long way towards paying for extra launches instead?   With $2 billion available in the budget every year, could NASA not then afford to fly two cargo missions where they were going to fly just one?   That would totally exceed the effectivel performance of a single Ares-V, no?

By my calculations, NASA could afford to fly at least 6-8 additional J-232 missions, including associated hardware costs (LSAM, CEV etc) every single year.

Also a higher flight rate means greater understanding of the launch vehicles and mission hardware in a shorter period of time, more cost effective manufacturing, larger workforce requirements (politically; a great thing), larger profits for the corporate sector (economically a good thing), and greater actual return for tax payers dollars.   I see everyone involved coming away with a smile of their faces.


Jupiter allows for NASA to follow either of these paths.

Ross.
Title: Re: DIRECT v2.0
Post by: riney on 06/05/2007 06:47 PM
This may well be a dumb question, and it's not intended to be any sort of objection to what you're saying; I'm just curious.

If you design your flight profile such that you don't have orbital velocity at CSM separation, so as to dump your second stage more easily, and you have to make a "third stage" SM burn to achieve it, what practical difference does it make whether your second stage _had_ (the operative word here) the extra performance to put you in your final orbit or not? It's not as though if something goes wrong with your SM engine you can get that second stage back. Why is it a negative that Orion has to burn if you're planning on doing it anyway? Is it an matter of wanting to hang on to more of the SM propellant for later use?

I understand of course that extra performance would be nice for higher orbits/heavier CSMs/whatever - I'm strictly trying to understand why it matters for the mission and spacecraft as designed.

--John Riney
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/05/2007 07:02 PM
Quote
kraisee - 5/6/2007  12:14 PM
BTW, I saw someone (you?) suggest a J-130 configuration.

Not me, but thanks for the info!
Title: Re: DIRECT v2.0
Post by: kraisee on 06/05/2007 07:13 PM
Quote
riney - 5/6/2007  2:47 PM

This may well be a dumb question, and it's not intended to be any sort of objection to what you're saying; I'm just curious.

If you design your flight profile such that you don't have orbital velocity at CSM separation, so as to dump your second stage more easily, and you have to make a "third stage" SM burn to achieve it, what practical difference does it make whether your second stage _had_ (the operative word here) the extra performance to put you in your final orbit or not? It's not as though if something goes wrong with your SM engine you can get that second stage back. Why is it a negative that Orion has to burn if you're planning on doing it anyway? Is it an matter of wanting to hang on to more of the SM propellant for later use?

I understand of course that extra performance would be nice for higher orbits/heavier CSMs/whatever - I'm strictly trying to understand why it matters for the mission and spacecraft as designed.

--John Riney

John,
The issue is that the same engine Ares-I fires three times just to reach a circular orbit, is the same engine which must work at the end of every Lunar visit in order to get a crew back - or else they die.   Components don't get much more critical than this.

This engine (based on the Shuttle OME) is expected to make one long burn (over 360 seconds!) and two short burns to get the CEV into circular orbit so it can dock with the LSAM/EDS correctly.

It then lays dormant for between 10 days (Lunar sortie missions) to up to 6 months (long duration stays) and then *must* make another long burn to get a crew home safely or we lose a crew.

6 months in orbit is quite a nasty environment for any materials, let alone Category A Critical engines which 4 people's lives will depend upon.   Whichever way you cut it, this is asking a lot of any engine.   The engineers we talk with feel that a long burn at the very start of the mission is just baiting the dragon in terms of risking failures of this engine.   Shuttle OME's have failed before, and we should expect no different here.

Jupiter flights require only a single short burn of this engine after insertion, to get the CEV into circular orbit.   That's it.

No long burn is required of this critical component.   And less than 10% of the total burn time is put on the engine compared to Ares-I flights.   Some of the team here actually just consider the single small circularization burn as a "useful test to make sure its working", but everyone here agrees that it isn't going to strain the engine anywhere near as much as the long ascent burn Ares-I flights require.   Doing that before cold soaking the engine for up to 6 months is begging for trouble.

Ross.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/05/2007 07:29 PM
Ross,

What's the delta-V required for the circularization burn on Jupiter versus the burns that Ares-I requires?
Title: Re: DIRECT v2.0
Post by: kraisee on 06/05/2007 08:51 PM
I don't have precise numbers to hand right this second (I am getting them for a comparison because I believe that would be very useful), but a quick back of the envelope calculation of Ares-I's dV requirement on the SM for achieving circular 120x120nm orbit looks like it is in the ballpark of 640-660m/s for all three burns.

It's more like 50-55m/s for Jupiter's single circ. burn.

Both these assume the same CEV (although Jupiter's Orion could actually be lighter because it doesn't need the fuel tanks for all that propellant any more).

Ross.
Title: Re: DIRECT v2.0
Post by: Will on 06/05/2007 09:20 PM
Quote
kraisee - 5/6/2007  1:14 PM


BTW, I saw someone (you?) suggest a J-130 configuration.   I have run this configuration a number of different ways, and the bottom line is it doesn't work well.   The three main engines guzzle all the fuel too fast and the rocket doesn't reach orbital speeds with anything approaching a reasonable payload - about 24mT.   It also suffers from very high max-Q dynamic pressures & dangerously high g-forces unless you throttling them right down and also turn one engine off for about the last few minutes of the flight.

Jupiter-120 already has engine-out capability from about T+45s onwards with just the regular two engines.   A third engine won't change this much, but kills performance, costs more and detracts from safety.


That was me. If you start the three engines at 66% and shut off the middle one about where you throttle back in the two engine flight profile, wouldn't that give similar fuel consumption to the two engine model, and engine out all the way?

Will
Title: Re: DIRECT v2.0
Post by: kraisee on 06/05/2007 11:15 PM
It is similar, given the extra engine mass you're brining up detracts from payload performance.   You get about 38-39mT to insertion.

However, with all three engines already operating down at almost their minimum setting, at 66% vs 60%, overall thrust still exceeds the max-Q requirements (<600psf) ESAS specified.   The J-130 seems to peak around 720psf.

The trade between two & three engines ultimately boils down to this:-

J-130: Keep the Core specification exactly the same for every flight, with or without EDS, attempting to increase processing reliability and to provide engine-out coverage during the first 45 seconds of ascent.   Lower performance, higher max-Q and lower LOC/LOM numbers result.

vs.

J-120: Reduce launch cost by $20m. Reduce the number of MPS units which can go critically wrong, increasing LOC/LOM.   Increase performance.   Accept that an abort becomes necessary if one MPS engine fails between T+0 and T+45s.

We've chosen to go for the second option.

Ross.
Title: Re: DIRECT v2.0
Post by: rumble on 06/06/2007 12:36 AM
Quote
kraisee - 5/6/2007  6:15 PM

snip

J-120: Reduce launch cost by $20m. Reduce the number of MPS units which can go critically wrong, increasing LOC/LOM.   Increase performance.   Accept that an abort becomes necessary if one MPS engine fails between T+0 and T+45s.

We've chosen to go for the second option.

Ross.

An engine-out abort between T+0 and T+45...  how would this work out in real life?  Would you go ahead and fly the vehicle until SRB burnout and then do the abort?  In that case, you could actually warn the crew & give them a countdown to abort.   ...assuming the event that caused engine out isn't catastrophic...

I'm assuming a non-catastrophic early engine out makes reaching orbit impossible, but otherwise introduces nothing life-threatening...except the abort...   and if a 1/2 thrust abort was an option (use a bit of the Jupiter margin to add this?), then even the abort has better safety.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/06/2007 12:45 AM
Exactly, it all depends on how severe the engine-out is.   An engine-out in the first 45 seconds would mean you aren't going to orbit.

If it is serious enough, you start shutting down the remaining MPS elements while you abort immediately using the LAS.   Keep the SRB's attached to the Core and you shouldn't have any issues with the vehicle following you.

If it is a less serious, say an instrumentation problem causes an unexpected premature engine shut-down event (like occurred on STS-51F IIRC), then my guess would be that you would probably wish to ride out the SRB portion of the flight, separate them safely away from your trajectory and then shut everything down while you use the LAS then.

There are a number of different approaches available in different situations too.

I don't personally know precisely where the line is drawn between the the various scenarios.    I believe those sorts of details should be determined by the engineers who would actually design and build the final abort systems - they can quantify the benefits/risks far more effectively than I can.

Ross.
Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/06/2007 03:16 AM
Quote
kraisee - 5/6/2007  2:51 PM
It's more like 50-55m/s for Jupiter's single circ. burn.

Could this burn be accomplished other ways if the SM fails to ignite after MECO?

Lee Jay
Title: Re: DIRECT v2.0
Post by: riney on 06/06/2007 04:14 AM
Quote
kraisee - 5/6/2007  2:13 PM
Doing that before cold soaking the engine for up to 6 months is begging for trouble.

Ross.

Thank you, Ross, for the very clear explanation. That description of your rationale makes perfect sense. However, it seems as though there is at least some flight experience with profiles of this sort (long burn -> long cold soak -> critical burn) - I'm thinking here of Soyuz TMA, which has to make something like 5 rendezvous burns to dock with ISS from its initial orbit - the first two of which are in the 300 second range (at least from the sketchy information I've been able to Google - this could of course be completely bogus and I could be an idiot for quoting it). It then has to cold-soak while docked for 6 months, and yet must be relied upon for a deorbit burn. I wonder how the safety numbers work out for that system? Admittedly, I'm sure we're talking about a whole lot less delta-v, and therefore less strain upon the propulsion system, than Orion would encounter.

--riney
Title: Re: DIRECT v2.0
Post by: CFE on 06/06/2007 06:07 AM
In DIRECT V2.x, does the mass of the Orion spacecraft take into account the fuel needed for the LOI burn?  I agree that it makes sense to offload the LOI burn requirement (and propellant mass) from the LSAM to the Orion CSM.  Because the DIRECT Orion isn't expected to burn as much propellant to achieve orbit, there would be a trade of LEO-insertion propellant mass for LOI propellant mass.  Would you expect the LOI propellant mass to be heavier or lighter than the amount of propellant saved during ascent?

In my view, DIRECT's biggest weakness is the inequity of masses between the two payloads that would have to dock in LEO.  Because Jupiter-232 still falls short of Ares V performance, that mass shortfall will have to be compensated with the Jupiter-120's performance advantage over Ares I.  However, if Jupiter 120 is only carrying the same payload mass that Ares I does, the performance advantages of the Jupiter family have been negated.  Perhaps if the LSAM ascent stage could be launched with the Orion capsule on the Jupiter 120, then docked to the LSAM descent stage and EDS that are launched on the Jupiter-232, the problem can be solved?  I know that NASA is going to laugh DIRECT out of existence if it relies on propellant transfer for the EOR-LOR mission.

I am not opposed to upgrading Jupiter-232 to Ares V-like performance, either.  Five-segment SRB's and a stretched core should all be considered, as the funding becomes available.  I'd also like to see a new, regen nozzle for the RS-68 with a higher area ratio.  It should come close to the Isp numbers predicted for STME, partially getting us back to the level of performance that was predicted for the 8.4m Ares V using "expendable SSME's."  

The beauty of the Jupiter concept is that it lends itself easily towards Michael Griffin's least-favorite buzzword: "Spiral Development."  The basic Jupiter 120 can probably be built on the money that NASA currently has budgeted for Ares I & V between now and 2012.  Upper stages, core stretches, longer SRB's and higher-Isp engines can all be added later when the money to develop them is available, beyond 2012.
Title: Re: DIRECT v2.0
Post by: clongton on 06/06/2007 12:18 PM
Quote
riney - 5/6/2007  12:14 AM

I'm thinking here of Soyuz TMA, which has to make something like 5 rendezvous burns to dock with ISS from its initial orbit - the first two of which are in the 300 second range (at least from the sketchy information I've been able to Google - this could of course be completely bogus and I could be an idiot for quoting it). It then has to cold-soak while docked for 6 months, and yet must be relied upon for a deorbit burn.
Soyuz engine is hypergolic, using UDMH/Nitrogen Tetroxide. Hypergolics can cold soak for indefinate periods of time. Orion is not hypergolic and therefore more time and use-critical.
Title: Re: DIRECT v2.0
Post by: Jim on 06/06/2007 01:27 PM
Quote
clongton - 6/6/2007  8:18 AM

Soyuz engine is hypergolic, using UDMH/Nitrogen Tetroxide. Hypergolics can cold soak for indefinate periods of time. Orion is not hypergolic and therefore more time and use-critical.

Orion is hypergolic
Title: Re: DIRECT v2.0
Post by: clongton on 06/06/2007 01:37 PM
Quote
Jim - 6/6/2007  9:27 AM

Quote
clongton - 6/6/2007  8:18 AM

Soyuz engine is hypergolic, using UDMH/Nitrogen Tetroxide. Hypergolics can cold soak for indefinate periods of time. Orion is not hypergolic and therefore more time and use-critical.

Orion is hypergolic
I was speaking long term. I knew hypergols were being employed as an intrim, but the baseline remains hydrogen/oxygen, or eventually methane/oxygen. Has the decision been made to stay hypergol permanently, or is it still an intrim solution?
Title: Re: DIRECT v2.0
Post by: kraisee on 06/06/2007 02:46 PM
The Lockheed design has specified hypergolic MMH/N2O4 and is using a modified variant of the Shuttle OME used in the OMS Pods - which itself is actually a development of the original Apollo SPS used on the CSM!

This is the current baseline, but a methane alternative is still being considered for the distant future.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/06/2007 03:14 PM
Quote
CFE - 6/6/2007  2:07 AM

In DIRECT V2.x, does the mass of the Orion spacecraft take into account the fuel needed for the LOI burn?  I agree that it makes sense to offload the LOI burn requirement (and propellant mass) from the LSAM to the Orion CSM.  Because the DIRECT Orion isn't expected to burn as much propellant to achieve orbit, there would be a trade of LEO-insertion propellant mass for LOI propellant mass.  Would you expect the LOI propellant mass to be heavier or lighter than the amount of propellant saved during ascent?

There are a number of different methods for performing the LOI.   Ares assumes the LSAM always does it, for both crewed and cargo flights alike.   You can get higher lunar surface mass performance if another module can perform it, such as the CEV on manned missions.   We are also investigating a very interesting option, of using the EDS to perform the LOI.   Current testing is ongoing, but early results are showing some very interesting positive results.   Additionally, there is a concept for using the EDS to perform the first phase of the descent too, which again is producing very interesting results in early testing.

Which option is finally chosen is still a decision "in work".

Quote
In my view, DIRECT's biggest weakness is the inequity of masses between the two payloads that would have to dock in LEO.  Because Jupiter-232 still falls short of Ares V performance, that mass shortfall will have to be compensated with the Jupiter-120's performance advantage over Ares I.  However, if Jupiter 120 is only carrying the same payload mass that Ares I does, the performance advantages of the Jupiter family have been negated.  Perhaps if the LSAM ascent stage could be launched with the Orion capsule on the Jupiter 120, then docked to the LSAM descent stage and EDS that are launched on the Jupiter-232, the problem can be solved?  I know that NASA is going to laugh DIRECT out of existence if it relies on propellant transfer for the EOR-LOR mission.

I tend to agree.   That's another of the reasons why my personal preference is for J-120 to only be used for LEO missions, and the Lunar program should go straight into an all-J-232 architecture.   EOR can still be supported if absolutely necessary, but LOR is the way to go as soon as confidence exists.


Quote
I am not opposed to upgrading Jupiter-232 to Ares V-like performance, either.  Five-segment SRB's and a stretched core should all be considered, as the funding becomes available.

Absolutely agree.   I still have to get the results optimised, but it looks like a 2x5seg SRB design, using a stretched 8.41m diameter ET-based Core with 4 RS-68's on it actually offers very similar performance to Ares-V - but starting from J-120 and creating that is far easier than developing Ares-V from Ares-I.


Quote
I'd also like to see a new, regen nozzle for the RS-68 with a higher area ratio.  It should come close to the Isp numbers predicted for STME, partially getting us back to the level of performance that was predicted for the 8.4m Ares V using "expendable SSME's."  

The base RS-68 which we are using in DIRECT v2.0 can indeed be upgraded.   For Ares-V, NASA has already baselined a new ablative nozzle upgrade version which is optimised for Sea-Level use on Delta-IV, but which offers 414.2s vac Isp and a 6% thrust increase.

A nozzle redesign (ablative or regenerative) optimised for higher altitude operation would offer increases too.

And a regeneratively cooled nozzle (optimised for high altitude) is still an upgrade option too.

All these upgrades are possible for Jupiter vehicles, and would increase performance above the current numbers we are proposing.   But we are specifically avoiding all such upgrades so that we don't have to pay for them in the short term, while cash is proving to be a problem and so that "new development" can not impact the schedule negatively.

I'm all-for upgrades as and when they are possible, but relying on them from the get-go isn't sensible.


Quote
The beauty of the Jupiter concept is that it lends itself easily towards Michael Griffin's least-favorite buzzword: "Spiral Development."  The basic Jupiter 120 can probably be built on the money that NASA currently has budgeted for Ares I & V between now and 2012.  Upper stages, core stretches, longer SRB's and higher-Isp engines can all be added later when the money to develop them is available, beyond 2012.

Jupiter-120 can actually be developed entirely on the less budget than Ares-I alone.

No Ares-V money is needed, so the billions for that can either be saved, used to speed up development of other parts of the program (EDS, LSAM), or even be used to build the Ares-V as a second LV if still needed.   My preference would be to speed up development of the EDS and LSAM and make the Lunar missions happen a few years earlier.

Jupiter-120 requires no changes at all to the current SRB's.   It requires only minimal changes to the existing RS-68 to man-rate it.   And it requires an "upgrade" program to the existing ET rather than a complete ground-up development program building an all-new Upper Stage with virtually brand-new air-start engine.   This approach reduces costs substantially compared to Ares-I.

Additionally, we save a lot of cash at the manufacturing and launch processing level by retaining existing compatibility with the existing 8.41m diameter tanking systems used for Shuttle today.   This means keeping most of the equipment at the manufacturing plant, deleting the current requirement for 2 brand-new MLP's for Ares-I, considerably fewer modifications to the MLP's (compared to widening the distance between SRB chambers by 6ft!) and considerably fewer changes to the work platforms inside the VAB.   The vast majority of systems in all these areas can be retained unchanged for Jupiter, but require heavy modification or outright replacement for Ares - and require it twice, not once.

Ross.
Title: Re: DIRECT v2.0
Post by: jongoff on 06/06/2007 03:26 PM
Ross,
Quote
Exactly, it all depends on how severe the engine-out is.   An engine-out in the first 45 seconds would mean you aren't going to orbit.

Silly thought.  If you're flying a 120 with the water shield payload you had previously talked about, you might still be able to reach orbit with an early engine out by opening a dump valve in the water tank section.  Drop the "payload" weight enough, and you might still be able to make orbit...

Just a crazy thought.

~Jon
Title: Re: DIRECT v2.0
Post by: kraisee on 06/06/2007 03:38 PM
Interesting idea Jon.   I'm not sure dumping one of your key sources of protection would be wise on a vehicle which has already suffered a significant failure though. :)

Ross.
Title: Re: DIRECT v2.0
Post by: Marsman on 06/06/2007 05:01 PM

Quote
Lee Jay - 5/6/2007 11:16 PM
Quote
kraisee - 5/6/2007 2:51 PM It's more like 50-55m/s for Jupiter's single circ. burn.
Could this burn be accomplished other ways if the SM fails to ignite after MECO? Lee Jay

Linear RCS thrusters are the back up for most burns.

Title: Re: DIRECT v2.0
Post by: Lee Jay on 06/06/2007 05:19 PM
Quote
Marsman - 6/6/2007  11:01 AM

Quote
Lee Jay - 5/6/2007 11:16 PM
Quote
kraisee - 5/6/2007 2:51 PM It's more like 50-55m/s for Jupiter's single circ. burn.
Could this burn be accomplished other ways if the SM fails to ignite after MECO? Lee Jay

Linear RCS thrusters are the back up for most burns.


That's what I had in mind.  It seems these might have the capacity to perform a 50m/s burn, but not a 600m/s burn.

If so, perhaps they could be given a bit more propellant for just such an event.  That could give you some time to do some on-orbit trouble-shooting of the SM.  I'm always impressed at what the engineers on the ground, in concert with the on-orbit crew, can get solved with some analysis, procedures, and software uplinks.

Another possible way to improve LOM/LOC by absorbing some margin?

Lee Jay
Title: Re: DIRECT v2.0
Post by: jongoff on 06/06/2007 06:01 PM
Quote
kraisee - 6/6/2007  8:38 AM

Interesting idea Jon.   I'm not sure dumping one of your key sources of protection would be wise on a vehicle which has already suffered a significant failure though. :)

You probably don't need to dump all of the water to still make orbit.  And if the engine failure is the benign sort (ie it shut down, but didn't explode), why would it be problematic?

~Jon
Title: Re: DIRECT v2.0
Post by: marsavian on 06/06/2007 07:06 PM
Quote
kraisee - 5/6/2007  1:14 PM

[....]

Jupiter-120 already has engine-out capability from about T+45s onwards with just the regular two engines.   A third engine won't change this much, but kills performance, costs more and detracts from safety.

Would it be possible to carry less payload to have engine-out capability from the start ? Would obviously mean the engines would throttle back earlier in normal flight to avoid high-g but it all helps LOM figures ;-).

Title: Re: DIRECT v2.0
Post by: kraisee on 06/06/2007 08:02 PM
Lee Jay:
I haven't got all the necessary details for the CEV's RCS system to be able to confirm whether it can be used as a backup for circularization.   I *guess* it might actually be possible, but I don't want to give anyone any false hope.

Jongoff & Marsavian:
Both offer interesting alternatives which would certainly allow full-coverage engine-out capability.

Precisely where the mass/performance line actually is has yet to be analysed.   I expect we can easily calculate a simple "fly only x tons and you full engine out capability from T+0.

But a detailed analysis of engine shutdowns at different times after launch, with a calculated proportion of overboard water is going to take too long for our small team here to completely calculate. We have a lot of other analysis to do ahead of that.   It might be possible, but I doubt there will be any numbers to prove it for a while :)

Ross.
Title: Re: DIRECT v2.0
Post by: Will on 06/06/2007 08:27 PM
I wonder how much difference a shield aft of the spacecraft would make. The vast majority of launchers that failed in the past 20 years didn't fail by exploding, and for many of the remainder on a manned mission your launch escape system would have yanked the capsule to someplace where the shield didn't help before the rocket exploded. (Or, if you prefer, burned very, very fast)

Will
Title: Re: DIRECT v2.0
Post by: clongton on 06/06/2007 08:36 PM
Quote
Will - 6/6/2007  4:27 PM

I wonder how much difference a shield aft of the spacecraft would make. The vast majority of launchers that failed in the past 20 years didn't fail by exploding, and for many of the remainder on a manned mission your launch escape system would have yanked the capsule to someplace where the shield didn't help before the rocket exploded. (Or, if you prefer, burned very, very fast)
In the case of a sudden catastrophic detonation, a blast shield would protect the spacecraft from flying debris which could be capable of damaging the LAS or the spacecraft’s own recovery mechanisms. An explosion of this magnitude would indicate something very, very wrong, and would occur suddenly, rather than as a cascading event. In that case, the abort algorithms would initiate the abort maneuver but the spacecraft would likely still be attached to the launch vehicle or be very, very close, because of the milliseconds of time we are talking about for this event to occur. A blast shield in this case would be very useful.

Also, don’t forget (as I did earlier today) that the Service Module engine is hypergolic. A launch vehicle explosion would certainly rupture the hypergolic tanks, exposing those fuels to each other and setting off a secondary explosion directly beneath the spacecraft itself, detonating and destroying the Service Module. This secondary explosion would likely be far more dangerous to Orion than the launch vehicle explosion because it would be occurring within the spacecraft stack itself. Having a blast shield between Orion and the launch vehicle would likely preclude this secondary extremely nasty event.
Title: Re: DIRECT v2.0
Post by: marsavian on 06/06/2007 09:47 PM
Talking of blast shields I found this Army Ceramic Armor Database study

http://stinet.dtic.mil/cgi-bin/GetTRDoc?AD=ADA362926&Location=U2&doc=GetTRDoc.pdf

more of the same including some vendors

http://gtresearchnews.gatech.edu/newsrelease/boron-carbide.htm
http://pubs.acs.org/cen/coverstory/8132/8132science.html
http://gtresearchnews.gatech.edu/newsrelease/TIB2.html
http://en.wikipedia.org/wiki/Chobham_armour
http://www.hexoloy.com/product-applications/armor
http://www.ceradyne.com/products/armor/aircraft-ballistics-panels.aspx
Title: Re: DIRECT v2.0
Post by: marsavian on 06/07/2007 10:15 AM
The ISS's new Mmod shields are nothing more sophisticated than 1 inch aluminium plates.

http://www.space.com/missionlaunches/070606_exp15_eva2.html

Yurchikhin and Kotov attached 12 aluminum panels to a sensitive area of the space station's Russian-built Zvezda service module -- which houses the ISS crew quarters -- during their Wednesday spacewalk.

"Everything is excellent," Yurchikhin said during the installation. "I guess we're lucky."

The new panels, along with five others installed by the Expedition 15 crew during the May 30 spacewalk, give Zvezda additional protection against impacts from micrometeorites and orbital debris. NASA officials have said that such micrometeorite and orbital debris (MMOD) strikes represent a major risk to the ISS and NASA shuttles in Earth orbit.

"The number one risk for the shuttle is MMOD when it's on orbit," Kirk Shireman, NASA's deputy ISS program manager, said before today's spacewalk. "It's also that way for ISS, although the station was designed to live in a debris environment."

Each of the 17 aluminum plates installed by Yurchikhin and Kotov during their two spacewalks are about an inch (2.5 centimeters) thick and cover a two-foot by three-foot (0.6- by 0.9-meter) patch of the ISS, NASA officials have said. They join six other panels that were installed by ISS astronauts during a 2002 spacewalk.

Title: Re: DIRECT v2.0
Post by: sbt on 06/07/2007 10:30 PM

Armour should be designed for the application. Stuff designed to stop
125mm APFDS or Orbital Debris is not necessarily the most weight and
volume efficient way of protecting a spacecraft from a disintegrating
launcher.

Armour should be optimised based on the likely threat, acceptable mass
and the vulnerability of what is being protected. And that last works
both ways - for example is their any point in fitting a man with a
helmet that will protect his head from threats that would be 100% fatal
due to trauma to the rest of the body?

Rick
Title: Re: DIRECT v2.0
Post by: marsavian on 06/07/2007 11:31 PM
True, but you need starting points for your specific rocket application analyses in terms of materials and current barrier applications as I don't think anything like this has been attempted before in a rocket but I could be wrong.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/08/2007 05:32 PM
Even ahead of that, you need a launcher concept which has sufficient performance margin to makesit a possibility.   Right now we don't have that.

Ross.
Title: Re: DIRECT v2.0
Post by: imfan on 06/08/2007 08:44 PM
Add RCS for circularization. To bet my few cents I would say it is possible since somewhere in ESAS there is part saying that RCS  are backup even for TEI(of course performed in more than one phase). Will try to look it up
Title: Re: DIRECT v2.0
Post by: Scotty on 06/08/2007 09:04 PM
Yes, the Orion's SM RCS is to be used as a back up for the SM main engine.
They will have the ability to use the RCS to make the TEI, but over a period of many Lunar orbits.
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/09/2007 01:21 AM
Quote
jongoff - 6/6/2007  11:01 AM

Quote
kraisee - 6/6/2007  8:38 AM

Interesting idea Jon.   I'm not sure dumping one of your key sources of protection would be wise on a vehicle which has already suffered a significant failure though. :)

You probably don't need to dump all of the water to still make orbit.  And if the engine failure is the benign sort (ie it shut down, but didn't explode), why would it be problematic?

~Jon

Does anyone know what Apollo 8 did?  The third stage, if fully loaded, could have sent them on a oneway trip to Pluto.

Title: Re: DIRECT v2.0
Post by: Will on 06/09/2007 03:25 AM
I notice that Direct's mass budget for the payload shroud is about half of what NASA assumes, for petty much the same volume. Why?

Will
Title: Re: DIRECT v2.0
Post by: kraisee on 06/09/2007 04:26 PM
Scotty,
For circularization, we only need to make ~50m/s burn total, but probably half of that could be applied on a per orbit basis.   It should still be safe, assuming the first burn raises the orbit to ~75x120nm then the second burn raises it to 120x120nm circular.

Can the 606 configuration Orion RCS provide that sort of impetus?   I'm guessing it can, but I don't have th enumbers in front of me.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/09/2007 04:29 PM
Will,
Because we were working with old mass fraction numbers for that part, not the new ones generated for the April 07 Ares-V.   We now have those in hand and have already applied them in house.   We're simply going to use exactly the same PLF as Ares-V.

While we definitely lost mass performance there, it should be noted that at the same time we were also able to reduce the mass of our Interstage considerably, down to just 5,195kg from our original "super safe estimate" of somewhere around 9,800kg.

We are still retaining full ESAS margins, and about 10% extra all of our own, and no, it's not some new technology, just plain old Al-Li.   Interestingly, this mass actually matches the flown Saturn S-II aft Interstage mass - which was 10m diameter, not 8.4m, so we know this is a safe assessment.

When these two changes were applied, the overall performance remained almost exactly the same.   Some other changes are in the pipeline.   Just as we've witnessed with Ares, the Jupiter's are continually evolving.   A Work In Progress.

Ross.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 06/10/2007 01:07 AM
I was just doing some thinking.  (I know, I know... That's a dangerous thing.)

Someone (I think it is Ross) earlier mentioned that a 3-stage version of Jupiter could deliver 250 metric tonnes to orbit.  

For comparison, after almost a decade of construction, the ISS still masses less than 250 tonnes.  Think about it--you could launch the entire ISS in a single launch with the big Jupiter!  That opens up all kinds of new possibilities for what you can do in space.


Changing the subject slightly, I was wondering just what the 250 tonne-to-orbit Jupiter ends up being?  I did some fooling around in Excel, and came up with it being something like a Jupiter 3542 or 3652, with the third stage being essentially exactly the 232's second stange, and the new second stage being around 1 million to a million-and-a-half pounds.  And I'm wondering how close my crude spreadsheet came to what you guys have figured out?
Title: Re: DIRECT v2.0
Post by: Antares on 06/10/2007 03:15 AM
I saw something about running engines at 66% (not sure which ones).  Running engines at some other level than what's advertised could bring Campbell problems.  RD-180 and SSME are the only continuously throttleable engines in the U.S. stable.
Title: Re: DIRECT v2.0
Post by: MATTBLAK on 06/10/2007 03:59 AM
Quote
SolarPowered - 10/6/2007  12:07 PM

I was just doing some thinking.  (I know, I know... That's a dangerous thing.)

Someone (I think it is Ross) earlier mentioned that a 3-stage version of Jupiter could deliver 250 metric tonnes to orbit.  

For comparison, after almost a decade of construction, the ISS still masses less than 250 tonnes.  Think about it--you could launch the entire ISS in a single launch with the big Jupiter!  That opens up all kinds of new possibilities for what you can do in space.


Changing the subject slightly, I was wondering just what the 250 tonne-to-orbit Jupiter ends up being?  I did some fooling around in Excel, and came up with it being something like a Jupiter 3542 or 3652, with the third stage being essentially exactly the 232's second stange, and the new second stage being around 1 million to a million-and-a-half pounds.  And I'm wondering how close my crude spreadsheet came to what you guys have figured out?

What about the second stage being a short-burn (stubby -- to keep the height down) powered by 4x J-2X and the third stage powered by the 232's 2x J-2X?. What would your first stage be --4x SRBs?
Title: Re: DIRECT v2.0
Post by: SolarPowered on 06/10/2007 05:37 AM
Matt, my crude spreadsheet said 2x SRBs.  The overall mass only went up by 1-1.5 million pounds over the 232, mostly for the new second stage.  So the 2-3 additional engines in the first stage is all you need to lift the the extra weight.

I was showing a very large gain from adding the additional stage.  (The extra Isp of the J-2x helps out a bit here.)

I readily admit that I'm an armchair rocket engineer, so my numbers could be completely wrong.
Title: Re: DIRECT v2.0
Post by: MATTBLAK on 06/10/2007 06:08 AM
With an 8.4m diameter first stage (corestage), the most RS-68s you could practically fit would be 4. You'd need to stretch the corestage to get extra propellant for the 4x RS-68s and to fit 5-Segment boosters. Add a second stage with 4x J-2X (most that would fit) and a third stage with 2x J-2X and you'd get pretty much the most capable "big dumb booster" America could build -- that is with *most* of the available tooling. And the payload to a 28.5-degree, 150-mile orbit I would estimate to be 170 metric tons (give or take). If you did away with the solids and used a pair of 3x RD-180 powered strap-on boosters, you'd get about another 10 tons payload capacity.

BUT: How tall would such a monster be? Ares V is said to be 358 feet tall -- almost the same height as Saturn V. Would our prospective monster Jupiter reach 390+plus feet high? Looking at my old documents for the 1993 Mars mission reference study, they state that the tallest a combined crawler and tower could be to fit in the VAB, without major mods, would be 410 feet. Keeping a booster and its Crawler/Tower within this limit would be major challenge.

Ross's original Direct Ver. 1.1 idea for an enhanced, stretched Direct booster capable of launching 130+plus tons would be the best overall compromise.
Title: Re: DIRECT v2.0
Post by: simcosmos on 06/10/2007 10:50 AM
Quote
MATTBLAK - 10/6/2007  7:08 AM

BUT: How tall would such a monster be? Ares V is said to be 358 feet tall -- almost the same height as Saturn V. Would our prospective monster Jupiter reach 390+plus feet high? Looking at my old documents for the 1993 Mars mission reference study, they state that the tallest a combined crawler and tower could be to fit in the VAB, without major mods, would be 410 feet. Keeping a booster and its Crawler/Tower within this limit would be major challenge.


Hello,

I might be wrong - need to check - but think that the VAB's height limit of ~410 feet (~124m) is just for the launcher's height (having in mind that some part of the core engines / boosters would be  'inside' the MLP).

(Maybe time to revise / double-check some of the VAB/MLP calcs + research that made in an older thread at these forums, about the height of a 3 stage AresI vs VAB capability to support such launcher config)).

Note: what will write next is just me thinking loud :)

On another note, a way to work some height limitations would be to adopt ~10m diameter for upper stages and payload fairings but while still keeping the core at 8.4m diameter (for better compatibility with existing STS support facilities, MLP, etc), I mean: the VAB will probably need some kind of work in its higher bays anyway (yes / no?).

Introducing a different diameter for the upper stage(s) / PLF could mean a little of extra production / transport / integration brainstorms - when comparing with the current assumption of just using the same 8.4m diameter for such upper stages - but, on the other hand, the launchers would be shorter for the same payload mass (better use of the available volume for propellants), there would be more space for eventual extra upper stage engine configurations (assuming a common thrust structure) and there would be more 'height budget' available for eventual future three stage launcher variants (beyond the boosters, I mean), etc.

Side note: this seems to be even more evident if we think about the current AresV design, which already assumes a core at 10m diameter. I sometimes wonder why AresV is not baselined with the same 10m diameter for a common bulkhead upper stage design, already thinking in long-term exploration goals (beyond NEO / Moon).

António
Title: Re: DIRECT v2.0
Post by: Scotty on 06/10/2007 02:50 PM
Kraisee;
I had the exact numbers for the 604 version of the Orion, but I can not find my notes.
If I remember correctly; the SM needs to make about a 600 feet per second burn to get the Orion from the Ascent Target to the initial elliptical orbit.
Then needs to make about a 100 feet per second burn to place Orion in its final circular orbit.
The total number is around 700 feet per second that is needed out of the SM to place Orion into orbit.
I'll see if I can dig up the exact numbers.
Title: Re: DIRECT v2.0
Post by: clongton on 06/10/2007 03:54 PM
Quote
MATTBLAK - 10/6/2007  2:08 AM

With an 8.4m diameter first stage (corestage), the most RS-68s you could practically fit would be 4.
MATT
We did a very detailed study and the 8.4m tank will fit 5 RS-68's. Just think of the Jupiter-23x and notice that it has 3 engines, with the outer 2 being protected by engine fairings like the Staturn-V.  Rotate/copy the 2 outer engines by 75 degrees and you've got a 5-engine core. That's also the identical configuration of engine arrangement used on the Ares-V. Why 75 and not 90 degrees? To keep the engine exhaust of the SRB's and the RS-68's from unduely impinging on each other. That also keeps the distance of all the RS-68 engines constant from each other across all 5 engines. But a 5-engine core was specifically studied and approved. It's just not included in the base proposal because it requires a different thrust structure. That structure would be based on the 3-engine but would weigh more in order to accomodate the additional 2 engines. That's a mass penalty of ~10mt not needed in the beginning. Note also that the 5-engine core can also be just 4 engines by omitting the center engine and blanking off its connections, in the same way as the Jupiter-120 and Jupiter-23x share the same common thrust structure.


The Jupiter family is capable of a lot more than what's covered in just the base proposal.
Title: Re: DIRECT v2.0
Post by: PaulL on 06/10/2007 06:57 PM
Quote
clongton - 10/6/2007  10:54 AM

Quote
MATTBLAK - 10/6/2007  2:08 AM

With an 8.4m diameter first stage (corestage), the most RS-68s you could practically fit would be 4.
MATT
We did a very detailed study and the 8.4m tank will fit 5 RS-68's. Just think of the Jupiter-23x and notice that it has 3 engines, with the outer 2 being protected by engine fairings like the Staturn-V.  Rotate/copy the 2 outer engines by 75 degrees and you've got a 5-engine core. That's also the identical configuration of engine arrangement used on the Ares-V. Why 75 and not 90 degrees? To keep the engine exhaust of the SRB's and the RS-68's from unduely impinging on each other. That also keeps the distance of all the RS-68 engines constant from each other across all 5 engines. But a 5-engine core was specifically studied and approved. It's just not included in the base proposal because it requires a different thrust structure. That structure would be based on the 3-engine but would weigh more in order to accomodate the additional 2 engines. That's a mass penalty of ~10mt not needed in the beginning. Note also that the 5-engine core can also be just 4 engines by omitting the center engine and blanking off its connections, in the same way as the Jupiter-120 and Jupiter-23x share the same common thrust structure.


The Jupiter family is capable of a lot more than what's covered in just the base proposal.

Do you mean 45 degrees instead of 75 degrees?  This would give you a "X" patern (SRBs are on each side) while a 90 degrees rotation would produce a "+" patern.


PaulL
Title: Re: DIRECT v2.0
Post by: CFE on 06/11/2007 04:38 AM
Before I begin, I'd like to apologize for steering this thread somewhat off-topic.

While the shuttle has to perform a roll maneuver, will Jupiter have to do the same when it lifts off?  I know that the shuttle roll has to do with the position of the flame ducts relative to the shuttle's trajectory.  With Jupiter going to an in-line configuration, will the flame ducts still be an issue?
Title: Re: DIRECT v2.0
Post by: Jorge on 06/11/2007 05:06 AM
Quote
CFE - 10/6/2007  11:38 PM

Before I begin, I'd like to apologize for steering this thread somewhat off-topic.

While the shuttle has to perform a roll maneuver, will Jupiter have to do the same when it lifts off?  I know that the shuttle roll has to do with the position of the flame ducts relative to the shuttle's trajectory.  With Jupiter going to an in-line configuration, will the flame ducts still be an issue?

Yes. Jupiter will roll so that when it begins pitching into the targeted trajectory, the SRBs are side-by-side, just as with the shuttle. For a typical due-east trajectory, this will be a 90-degree roll to the right off the pad.
Title: Re: DIRECT v2.0
Post by: MATTBLAK on 06/11/2007 06:19 AM
Quote
clongton - 11/6/2007  2:54 AM

Quote
MATTBLAK - 10/6/2007  2:08 AM

With an 8.4m diameter first stage (corestage), the most RS-68s you could practically fit would be 4.
MATT
We did a very detailed study and the 8.4m tank will fit 5 RS-68's. Just think of the Jupiter-23x and notice that it has 3 engines, with the outer 2 being protected by engine fairings like the Staturn-V.  Rotate/copy the 2 outer engines by 75 degrees and you've got a 5-engine core. That's also the identical configuration of engine arrangement used on the Ares-V. Why 75 and not 90 degrees? To keep the engine exhaust of the SRB's and the RS-68's from unduely impinging on each other. That also keeps the distance of all the RS-68 engines constant from each other across all 5 engines. But a 5-engine core was specifically studied and approved. It's just not included in the base proposal because it requires a different thrust structure. That structure would be based on the 3-engine but would weigh more in order to accomodate the additional 2 engines. That's a mass penalty of ~10mt not needed in the beginning. Note also that the 5-engine core can also be just 4 engines by omitting the center engine and blanking off its connections, in the same way as the Jupiter-120 and Jupiter-23x share the same common thrust structure.


The Jupiter family is capable of a lot more than what's covered in just the base proposal.

5 would fit, eh? Good to know -- I certainly wasn't sure and don't mind being corrected!! But wouldn't such an 8.4m corestage have to be stretched too much, to get the required propellant to have a decent burn time? Or would this be a short-burning stage, even with a length to match 5-Segment boosters, therefore needing a bigger upper stage (EDS) with more engines?
Title: Re: DIRECT v2.0
Post by: BogoMIPS on 06/11/2007 01:38 PM
I think you'd basically end up with an 8.4m equivalent of the Ares V, where you add length instead of diameter to increase your fuel capacity to the same levels.

I'm completely unqualified to tell how the performance of and 8.4m Jupiter-25x would copmare to the equivalent 10m Ares V (assuming the same fuel capacity).  My guess is the limiting factor might be the height of the VAB.

Of course, the Ares V also adds 5-segment boosters, which invalidates my post entirely. =)
Title: Re: DIRECT v2.0
Post by: marsavian on 06/11/2007 02:03 PM
Quote
BogoMIPS - 11/6/2007  8:38 AM

I think you'd basically end up with an 8.4m equivalent of the Ares V, where you add length instead of diameter to increase your fuel capacity to the same levels.

I'm completely unqualified to tell how the performance of and 8.4m Jupiter-25x would copmare to the equivalent 10m Ares V (assuming the same fuel capacity).  My guess is the limiting factor might be the height of the VAB.

Of course, the Ares V also adds 5-segment boosters, which invalidates my post entirely. =)

NASA thinks it's worth 10mT

p13-14

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002798_2007001569.pdf
Title: Re: DIRECT v2.0
Post by: wingod on 06/11/2007 04:38 PM
Quote
MATTBLAK - 10/6/2007  1:08 AM

With an 8.4m diameter first stage (corestage), the most RS-68s you could practically fit would be 4. You'd need to stretch the corestage to get extra propellant for the 4x RS-68s and to fit 5-Segment boosters. Add a second stage with 4x J-2X (most that would fit) and a third stage with 2x J-2X and you'd get pretty much the most capable "big dumb booster" America could build -- that is with *most* of the available tooling. And the payload to a 28.5-degree, 150-mile orbit I would estimate to be 170 metric tons (give or take). If you did away with the solids and used a pair of 3x RD-180 powered strap-on boosters, you'd get about another 10 tons payload capacity.

BUT: How tall would such a monster be? Ares V is said to be 358 feet tall -- almost the same height as Saturn V. Would our prospective monster Jupiter reach 390+plus feet high? Looking at my old documents for the 1993 Mars mission reference study, they state that the tallest a combined crawler and tower could be to fit in the VAB, without major mods, would be 410 feet. Keeping a booster and its Crawler/Tower within this limit would be major challenge.

Ross's original Direct Ver. 1.1 idea for an enhanced, stretched Direct booster capable of launching 130+plus tons would be the best overall compromise.

With LOX/RP for the first stage, along with RD-180's this problem goes away.

Title: Re: DIRECT v2.0
Post by: clongton on 06/11/2007 04:40 PM
Quote
BogoMIPS - 11/6/2007  9:38 AM

I think you'd basically end up with an 8.4m equivalent of the Ares V, where you add length instead of diameter to increase your fuel capacity to the same levels.

I'm completely unqualified to tell how the performance of and 8.4m Jupiter-25x would copmare to the equivalent 10m Ares V (assuming the same fuel capacity).  My guess is the limiting factor might be the height of the VAB.

Of course, the Ares V also adds 5-segment boosters, which invalidates my post entirely. =)
There are a couple of different really good configurations of the 5-engine Jupiter, but the main point to remember, when comparing it to the Ares-V is that the Ares-V tries to do far too much with its lower stage, and that robs the entire system of performance. Rocket science is no where near far enough along to do heavy lift with SSTO, and the Jupiter doesn't even attempt that. An upper stage is needed in order to have good system performance for heavy lift, at least with today's state of capability, so the Jupiter maximizes the entire system to get the most from the lower/upper stage combination. When you approach it from this "system" pov, you'd be amazed what you can do with a Jupiter-254, which is a standard ET and 4-segment SRB's. Of course, one can always expand the system beyond that with several different options, including, but not limited to the stretched ET. But it's nice to know that we don't have to in order to get really substantial heavy lift from the system.

For really HEAVY heavy lift, the family supports Jupiter-3xx options, but the need for launch vehicles like that, which are 300mT+ to LEO, are not well defined at present, so we are not pushing them. But we did look at them enough to verify that the Jupiter-3xx is a viable member of the family for future needs, should the need for such a capacity ever become real. The Ares-V isn't capable of evolving to anything like that.
Title: Re: DIRECT v2.0
Post by: marsavian on 06/11/2007 05:36 PM
The thing that strikes me about the whole Ares architecture is that there is no engine-out facility
in any of it ! Lose an engine on anything and you lose the mission. Saturn V proved how useful having engine-out facility was in real world usage. It might be prudent for the DIRECT team to try and ensure that each Jupiter stage has engine-out facility to provide another glaring advantage over Ares even if you lose some mT in payload in the process.
Title: Re: DIRECT v2.0
Post by: BogoMIPS on 06/11/2007 05:59 PM
Quote
With LOX/RP for the first stage, along with RD-180's this problem goes away.

Agree whole-heartedly, but you add whole new non-technical (i.e. political) problems (no longer shuttle-derived, engine without US heritage, etc.) that are likely even harder to resolve.
Title: Re: DIRECT v2.0
Post by: SolarPowered on 06/11/2007 06:32 PM
Quote
MATTBLAK - 9/6/2007  8:59 PM

Quote
SolarPowered - 10/6/2007  12:07 PM

I was just doing some thinking.  (I know, I know... That's a dangerous thing.)

Someone (I think it is Ross) earlier mentioned that a 3-stage version of Jupiter could deliver 250 metric tonnes to orbit.  

For comparison, after almost a decade of construction, the ISS still masses less than 250 tonnes.  Think about it--you could launch the entire ISS in a single launch with the big Jupiter!  That opens up all kinds of new possibilities for what you can do in space.


Changing the subject slightly, I was wondering just what the 250 tonne-to-orbit Jupiter ends up being?  I did some fooling around in Excel, and came up with it being something like a Jupiter 3542 or 3652, with the third stage being essentially exactly the 232's second stange, and the new second stage being around 1 million to a million-and-a-half pounds.  And I'm wondering how close my crude spreadsheet came to what you guys have figured out?

What about the second stage being a short-burn (stubby -- to keep the height down) powered by 4x J-2X and the third stage powered by the 232's 2x J-2X?. What would your first stage be --4x SRBs?

Matt,

I learned some really interesting things about stage size from my simple spreadsheet.  One of which was that the optimum mass ratio for both the second and the third stages is around 2.35.  If you go lower or higher, you end up with a heavier total launch weight.

For a three-stage, 250 mT launcher, that number makes the Jupiter 232's second stage almost perfect for a third stage.  (Obviously, you'd have to strengthen it a bit to support the additional payload.)

This is based on a really rough spreadsheet, with these assumptions: Total delta-V required, including allowances for gravitational loss and aerodynamic drag, is 9,000 meters/second.  Second and third stage were at vacuum Isp of 448 for the entire burn.  I lumped the solids and RS-68s in the first stage together and guessed a combined Isp of 380 assumed for the entire burn.  Second and third stage mass fractions are 0.94.  First stage mass fraction is 0.90.

This certainly isn't detailed enough to design an actual rocket that you'd spend billions of dollars on, but it was really interesting seeing how things interacted.  Adding a third stage made a big difference in how much you can launch with a given launch vehicle.  Depending on the exact assumptions, you could get down to launch weight/payload ratios in range of 10:1 or so.
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/11/2007 07:28 PM
Quote
marsavian - 11/6/2007  10:36 AM

The thing that strikes me about the whole Ares architecture is that there is no engine-out facility
in any of it ! Lose an engine on anything and you lose the mission. Saturn V proved how useful having engine-out facility was in real world usage. It might be prudent for the DIRECT team to try and ensure that each Jupiter stage has engine-out facility to provide another glaring advantage over Ares even if you lose some mT in payload in the process.

Actually the Jupiter-254 can beat the AresV on TLI which is the only number that really matters in the end.  I also like the Jupiter-244 because we can have an engine out capability on both stages for relatively low payload penalty provide we have a 3rd stage.  Though this configuration is more expensive.  The big question is a boost in TLI worth having true 3rd stage like the Saturn V had?  At the lower end of the Jupiter family like the Jupiter-221 and 232 it’s a wash or even a negative to have a 3rd stage but if you increase the power of the 1st stage (ie 4 – 5 engines) you need a heavier 2nd stage to take advantage of that which then gives you a negative return on TLI unless you use a true 3rd stage because that’s a lot of empty tank and heavy engines to send to the moon when one J2 and a smaller full tank will do the job.

The nice thing about the Jupiter Family is that it is a family with a number of downgrade and upgrade options.  The Ares V tank requires 5-Seg SRB and five engines to get it off the ground so the family is max out from the get go which is big problem should we have an over mass conditions for the spacecraft.  At which point the only way to reconnect up the Architecture is reduce the mission scope or go to a non-linear cost curve for the spacecraft for a minimal mass reduction
Title: Re: DIRECT v2.0
Post by: Scotty on 06/11/2007 10:10 PM
One thing you need to consider; there is a maximum stack height in the VAB.
The existing planned Ares V pushed the stack height to near the limits.
That is why the change to the 10 meter core, go wider not higher.
Remember the old car commercial "Wider is Better!"?
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/12/2007 12:53 AM
Quote
Scotty - 11/6/2007  3:10 PM

One thing you need to consider; there is a maximum stack height in the VAB.
The existing planned Ares V pushed the stack height to near the limits.
That is why the change to the 10 meter core, go wider not higher.
Remember the old car commercial "Wider is Better!"?

Understood.  So as long as we stay at or below the AresV we should be okay?

Which is below the SaturnV + Tower?

Why did they go to 10m?  I thought it was due to the 5 engine configuration and engine spacing requirements.

Have you noticed how little net thrust the five seg SRB produces over the four seg SRB for the first 30 seconds or so?

One thing I have noticed in trying to optimize the Ares V is that its low thrust to weight ratio prevents using a stronger 2nd stage.  The Jupiter on the other hand starts shorter and can have more power in the main engines allowing for a stronger second stage getting us closer to the equal deltaV for equal ISP rule.  Which is pretty close to a real life optimization.  

Ironically the best Ares V I have found is 10m standard length tank with 4 segment SRB.  But we can’t do that because we have to have to o’so precious stick.

Also is just me or does the aspect ratio of the 5 Seg look odd vs all other solid motors.  It would seem to me that the diameter and length ratio is optimal at a certain ratio?
Title: Re: DIRECT v2.0
Post by: kraisee on 06/12/2007 01:02 AM
PaulL & MATTBLAK:

Here are our suggested engine arrangement for 2, 3, 4 and 5 engine Core configurations.






As you can see, there is plenty of clearance all around - especially with regard to the SRB's.


MATTBLAK & BogoMIPS:

A triple stage vehicle is unlikely to ever be utilised due mainly to safety numbers - even for unmanned use.

Just to clarify, it would actually not be too difficult to make a three-stage cargo launcher fit below the ~405-410ft height level (there were Saturn-V upgrades planned to this height (363'+41.5') which would have worked without modifying the VAB).   If the safety weren't an issue, the LAS on top of the Orion means the PLF under the Orion might be a touch short, but still doable.

But this is not something we actually need for any of the planned missions we'd like to do.

With more than 100mT lift capability in the initial phases of the DIRECT architecture, there would have to be a very specific requirement to lift chunks in larger pieces than that to ever make it worthwhile developing a second, larger booster.

In short: For the cost of developing a second launcher, you could actually fly about 100 extra "existing" J-232 launchers instead, each lifting more than 100mT.   That means that for the cost of just developing (not actually including flying) the second launcher system, you can loft 10,000 tons in 100mT chunks.   That is far more cost effective.

The only requirement for a larger booster than J-232, would be to lift a heavy payload which can *not* be broken down into 100mT chunks.

I personally can't actually think of any items at all which *can't* be broken down into 100mT chunks, but which *can* break down into 150 or 170mT chunks to fly on such a larger launcher.

Nuclear propulsion modules break down fine, habitat modules do, unmanned probes certainly do, propellant modules easily do, even Lunar & Mars landers all do.   I can not think of a single specific example of a module which would force a launcher requirement larger than 100mT to LEO.


Wingod/BogoMIPS:

The problem with the RP1 Core is that you can't fly a Core without an Upper Stage.   RP-1 engines don't offer sufficient Isp to effectively work all the way to orbit.   That means you need one LOX/LH2 Core for the 45mT launcher and a different Core for the multi-stage launchers, which means we're back to having the cost of two LV's all over again.

I think the better solution would be to replace the SRB's with an RP1/LOX booster.   Assuming you have similar lift off thrust, having a much more constant thrust curve offers significantly better performance than the SRB's currently do.   A 15mT performance increase in performance is quite possible by replacing the solid boosters with RP1 based boosters.   Of course the politics of taking ATK/Utah out of the game might prove to be unworkable in the real world, but that's a different issue entirely.


marsavian:

The Jupiter-120 already has engine out capability from ~T+45 second onwards.   A few techniques are available to improve even on that, but we have not yet analysed them in detail.   Additionally, we ground light our main engines - just like STS - which adds an important layer of safety too.

The Jupiter-232 has engine out for both stages, although, again, it really needs the Core engines for about the first minute of flight.

From this perspective, we are already well ahead of both Ares-I and Ares-V.

Ross.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/12/2007 02:13 AM
Over on NASAWatch.com, Keith Cowing posted:-

Political Objections to Ares 1B Are Apparently On The Rise

Editor's note: Over the past several weeks I have had an opportunity to talk with people who are working space policy - and related issues - for both Democratic and Republican presidential candidates and party organizations. One common theme is readily apparent (so far) - on both sides: a greater use of private sector solutions - i.e. the use of commercial launch vehicles - specifically EELVs - as the launch vehicle of choice for the CEV. No one seems to be all that fond of continuing the development of Ares 1 (a government-owned solution) or the cost of developing something that already exists i.e. something you can buy now (EELVs). Of course, much can change between now and the election - and who will run NASA in 2009. But the writing on the wall is starting to become rather clear.

---=== End ===---

Wow.   I didn't realise Ares-I was getting that unpopular with the politico's.


Given our position on DIRECT is all about getting Heavy Lift, I would not have an objection to NASA concentrating on Jupiter or Ares-V and switching the CLV program over to an EELV.

I think there are going to be political objections to using the Russian RD-180 engine for such a high profile purpose (possibly solved by actually manufacturing US versions?), and there are certainly practical advantages to man-rating the Delta-IV's RS-68 & RL-10-B-2's, so I suspect Delta-IV may be ahead in such a choice.

But I could go for either EELV in such a CLV scenario, while working on an SDLV solution for the Heavy Lift.

Ross.
Title: Re: DIRECT v2.0
Post by: Scotty on 06/12/2007 02:13 AM
The reason for the switch from the 8.4 meter core to 10 metes is that the RS68's are not a efficient as the SSME.
he original plan for Ares V was 5 SSME's.
The lower isp means the RS68's have to burn more fuel to get the same total impulse.
They could not make Ares V taller, so they made it fatter.
Title: Re: DIRECT v2.0
Post by: kraisee on 06/12/2007 02:22 AM
Agreed Scotty.

The reason though, was that they had to have the largest booster possible to go with the puny Ares-I CLV.

If they "balanced" the CLV / CaLV performance proportions a little better (by making a more powerful CLV), the need for quite such a massive rocket goes away.

"Balancing" it better also brings the performance back within the ability of the existing 4-seg SRB's and an 8.4m diameter Core arrangement.   Being able to use the existing infrastructure in this way greatly reduces development costs and schedules massively and automatically leads to a solution broadly like DIRECT's.

The change to 10m diameter affects too many other things to be efficient.   Everything from manufacturing, transportation, VAB, MLP, Crawlers & Pad all need to be changed if ditching the existing 8.4m arrangement.   A lot can be saved by not having to go down that path in the first place.

But I'm preaching to the choir here :)

Ross.
Title: Re: DIRECT v2.0
Post by: zinfab on 06/12/2007 02:42 AM
Suddenly, DIRECT may turn into Griffin's last ticket to save the whole danged development project. If they go EELV for Orion, will NASA still get money for heavy-lift?
Title: RE: DIRECT v2.0
Post by: RedSky on 06/12/2007 03:10 AM
So with this news, what might tomorrow's 1pm EDT NASA-wide update with the administrator & deputy administrator be about?  Trying to defuse Ares I issues?  Or show what great progress there's been.  Or announce a change of plans?  Or hard line digging in?  Maybe its the consequence of JY's May 23rd prediction?   ;)   Is the Constellation-wide two week stand down still on?
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/12/2007 03:48 AM
Quote
zinfab - 11/6/2007  7:42 PM

Suddenly, DIRECT may turn into Griffin's last ticket to save the whole danged development project. If they go EELV for Orion, will NASA still get money for heavy-lift?

No, what Mike needs to do is drive towards the Jupiter-120.  After that add an upper stage (Jupiter-232) and you are good to go for a 2xHLV to the moon with more mass than the current Ares 1/5 plan.  With an ELV you are still stuck in LEO as with the Ares I but with a major STS workforce disruption.

I still think the ELV’s could help get the Orion up and running but only if it helps get the Jupiter off the ground.  If it takes resources away I’d rather deal with an excess performance issue for the ISS than an under performance.

Doing 10xELV everytime we go to the moon is a non-starter. Any significant payload increase to the ELV is new launch system.


Title: Re: DIRECT v2.0
Post by: Smatcha on 06/12/2007 04:00 AM
Quote
Scotty - 11/6/2007  7:13 PM

The reason for the switch from the 8.4 meter core to 10 metes is that the RS68's are not a efficient as the SSME.
he original plan for Ares V was 5 SSME's.
The lower isp means the RS68's have to burn more fuel to get the same total impulse.
They could not make Ares V taller, so they made it fatter.

I actual showed Bill C’s boys the 10m 5xRS-68 4-Seg SRB version in Nov 2005.  Back when it was a 4-Seg SRB 8.4m 5xSSME.  The said that was the way to go ESAS has spoken RS-68 were bad.  Not three months latter it was RS-68 good SSME bad.

I understand the ISP issue but the 10m 4-Seg 5xRS-68 beats the AresV 5-Segment.  It’s just a better balance between first and second stages.  All that happens is that you stage earlier and closer to half the deltaV to orbit.

5-Seg Net Thrust vs 4-Seg Net Thrust first 30 seconds?

Title: Re: DIRECT v2.0
Post by: CFE on 06/12/2007 07:22 AM
In regards to the politicos getting angry about Ares I being picked over commercial competitors, I am reminded of an interview with Jeff Hanley, recently published in AIAA's "Aerospace America" magazine.  He states that he envisions Ares I being transitioned to a private operator as time goes on, and states that NASA's not trying to compete with the private sector.

The overall interview is very interesting.  His comments sound like they're coming from the right place, but they beg the obvious question: why design Ares I in the first place, if you're not interested in competing with the private sector?  Too many people have bought off on the myth that EELV's are unsafe for manned spaceflight.  That should have all been refuted by the Atlas V human-rating study and the TeamVision report.

Turn back the clocks to early 2005, before Michael Griffin instituted ESAS.  Of the CE&R studies solicited by NASA, the majority favored EELV's for crew launch.  I particularly like the Boeing proposal (http://astronautix.com/craft/cevoeing.htm) which used a 4.5 meter diameter capsule (unlike the current Orion, which was seemingly designed with a "more volume is better" mentality) launched on a Delta IV with a 5 meter upper stage and six SRB's.

I think what Hanley is describing is an arrangement like United Space Alliance, where USA or another contractor would operate the vehicle, despite its lack of commercial viability.  Cynically, it sounds like an attempt to preserve the status quo, rather than a technically or economically sound decisions.
Title: Re: DIRECT v2.0
Post by: marsavian on 06/12/2007 02:47 PM
Here's the link for that Ares I commentary

http://www.nasawatch.com/archives/2007/06/political_objec.html

It's not surprising politicians are asking questions. They were promised SOON by Horowitz and it obviously isn't compared to EELVs.
Title: Re: DIRECT v2.0
Post by: Bill White on 06/12/2007 02:57 PM
kraisee writes:

Given our position on DIRECT is all about getting Heavy Lift, I would not have an objection to NASA concentrating on Jupiter or Ares-V and switching the CLV program over to an EELV.

Isn't there a risk that once an EELV CEV flies to ISS a future Congress will decide NOT to build any heavy lift? And once that infrastructure is dismantled, it will be difficult for an even later Congress to re-constitute that infrastructure.

Pad 39 for example. If we fly CEV on EELV and Pad 39 and the VAB and the crawlers decay, EELV only becomes a very real possibility.

I recall one of your objections to Ares 1 being the danger that Ares 1 could be all we might ever get. Would you be content with an EELV only program?



Title: Re: DIRECT v2.0
Post by: Danny Dot on 06/12/2007 03:09 PM
Quote
CFE - 12/6/2007  2:22 AM

In regards to the politicos getting angry about Ares I being picked over commercial competitors, I am reminded of an interview with Jeff Hanley, recently published in AIAA's "Aerospace America" magazine.  He states that he envisions Ares I being transitioned to a private operator as time goes on, and states that NASA's not trying to compete with the private sector.

The overall interview is very interesting.  His comments sound like they're coming from the right place, but they beg the obvious question: why design Ares I in the first place, if you're not interested in competing with the private sector?  Too many people have bought off on the myth that EELV's are unsafe for manned spaceflight.  That should have all been refuted by the Atlas V human-rating study and the TeamVision report.

Turn back the clocks to early 2005, before Michael Griffin instituted ESAS.  Of the CE&R studies solicited by NASA, the majority favored EELV's for crew launch.  I particularly like the Boeing proposal (http://astronautix.com/craft/cevoeing.htm) which used a 4.5 meter diameter capsule (unlike the current Orion, which was seemingly designed with a "more volume is better" mentality) launched on a Delta IV with a 5 meter upper stage and six SRB's.

I think what Hanley is describing is an arrangement like United Space Alliance, where USA or another contractor would operate the vehicle, despite its lack of commercial viability.  Cynically, it sounds like an attempt to preserve the status quo, rather than a technically or economically sound decisions.

And don't forget that Ares 1 is a NASA rocket.  Apparently Marshal Space Flight Center is acting as prime contractor for Ares 1.  Read into this lots of high level government jobs at Marshal to support Ares 1.  Of course NASA picked Ares 1 over EELVs -- it is their rocket.

Danny Deger
Title: Re: DIRECT v2.0
Post by: tankmodeler on 06/12/2007 03:18 PM
Quote
Bill White - 12/6/2007  10:57 AM
I recall one of your objections to Ares 1 being the danger that Ares 1 could be all we might ever get. Would you be content with an EELV only program?
Perhaps if NASA voluntarily swaps over to a Jupiter based HLV for lunar and beyond "real-soon-now" and endorsed an EELV based CLV, the funding and programs could be retained.

Of course, pigs will fly before NASA backs down off this one.

Paul
Title: Re: DIRECT v2.0
Post by: Bill White on 06/12/2007 03:37 PM
Quote
tankmodeler - 12/6/2007  10:18 AM

Quote
Bill White - 12/6/2007  10:57 AM
I recall one of your objections to Ares 1 being the danger that Ares 1 could be all we might ever get. Would you be content with an EELV only program?
Perhaps if NASA voluntarily swaps over to a Jupiter based HLV for lunar and beyond "real-soon-now" and endorsed an EELV based CLV, the funding and programs could be retained.

Of course, pigs will fly before NASA backs down off this one.

Paul

Would that be less expensive than an all-Jupiter program?
Title: Re: DIRECT v2.0
Post by: Davie OPF on 06/12/2007 04:23 PM
Quote
marsavian - 12/6/2007  9:47 AM

Here's the link for that Ares I commentary

http://www.nasawatch.com/archives/2007/06/political_objec.html

It's not surprising politicians are asking questions. They were promised SOON by Horowitz and it obviously isn't compared to EELVs.

" Editor's update: Contrary to what some of the space chat pages would suggest in response to this post last night, the individuals I have spoken with are not other space chat site posters whose opinions are pulled out of thin air. Rather, these are individuals, many of whom who work here in Washington, DC with significant positions in government, politics, industry, and academia. Many are seasoned political and campaign veterans."

Why does he have to be so insulting? This is not the first time and I'm not sure why people keep linking these rants.
Title: Re: DIRECT v2.0
Post by: Smatcha on 06/12/2007 06:00 PM
Quote
Bill White - 12/6/2007  7:57 AM

kraisee writes:

Given our position on DIRECT is all about getting Heavy Lift, I would not have an objection to NASA concentrating on Jupiter or Ares-V and switching the CLV program over to an EELV.

Isn't there a risk that once an EELV CEV flies to ISS a future Congress will decide NOT to build any heavy lift? And once that infrastructure is dismantled, it will be difficult for an even later Congress to re-constitute that infrastructure.

Pad 39 for example. If we fly CEV on EELV and Pad 39 and the VAB and the crawlers decay, EELV only becomes a very real possibility.

I recall one of your objections to Ares 1 being the danger that Ares 1 could be all we might ever get. Would you be content with an EELV only program?




Even with ELV’s we are still stuck in LEO even if it is a more efficient path to LEO than the Ares 1.  All ELV upgrades that get you anywhere close to the Jupiter-232 are new launch systems.  

The basic debate post Ares 1/5 will be whether DIRECT’s 2xHLV STS based solution makes more sense than a 10xELV.  NASA best line of defense will be DIRECT at that point because it will get NASA back to what it originally promised an STS based solution would do for the politicians.  I just don’t see the politics every aligning 100% against the STS base.  Where Mike and Company messed up is the current approach is only superficially STS based sharing almost none of the actual infrastructural advantages of being STS based.  I think it’s also important to point out some of the most expensive components are already off the shelf ELV components.  With a little more coordination even more ELV systems could be incorporated making the Jupiter a hybrid of the STS and ELV families.  Imaging a Jupiter-120 lofting a “full” ELV upper stage into orbit.  Instant hybrid with a 2x improvement over either the current STS or ELV fleet.

At the end of the day the budget will be the same for VSE regardless of how it is split up organizationally.  The only difference in any plan will be in what badge everyone is has on NASA, USA, Boeing, Lockheed/Martin, ATK etc.  The skills we need are what they are and generally in the same locations throughout the country.  There will be some transition but a good plan will use the natural attrition rate to make those shifts as painless as possible helping keep everyone focused on the difficult technical objectives of VSE and not their jobs, badges or homes.

Title: Re: DIRECT v2.0
Post by: kraisee on 06/12/2007 08:06 PM
Quote
Bill White - 12/6/2007  10:57 AM

kraisee writes:

Given our position on DIRECT is all about getting Heavy Lift, I would not have an objection to NASA concentrating on Jupiter or Ares-V and switching the CLV program over to an EELV.

Isn't there a risk that once an EELV CEV flies to ISS a future Congress will decide NOT to build any heavy lift? And once that infrastructure is dismantled, it will be difficult for an even later Congress to re-constitute that infrastructure.

Pad 39 for example. If we fly CEV on EELV and Pad 39 and the VAB and the crawlers decay, EELV only becomes a very real possibility.

I recall one of your objections to Ares 1 being the danger that Ares 1 could be all we might ever get. Would you be content with an EELV only program?

A very valid point, and one I've thought long and hard about.

The simple fact is that, compared to Ares-I, either EELV is dirt cheap to get operating as a manned launcher.   I've heard numbers from inside LM (before ULA) that just $1bn, spread over a three year period would do the job for Atlas-V, and similar for Delta-IV.

If you did that, you could *afford* to spend the bulk of Ares-I's development money making something like DIRECT's Jupiter *at the same time*.   Unlike Ares, where the Lunar booster must wait until after the CLV, this solution would allow both CLV and Lunar booster to be developed in parallel.

At that point, you get a manned Orion flight around the time of the Shuttle's retirement, and you get three years of development for the Jupiter-120 done before STS retires too.

From there, you have the EELV launcher doing the 20mT CEV-only flights, and you *also* retain the 100,000+ STS workers around the country, now gainfully employed by the Jupiter Program which is - by then - half way to achieving Lunar missions.

That approach provides the US the ability to launch a CEV on any of: 12mT, 20mT, 45mT and 100mT launchers, and satisfies the two goals Congress has already approved: Humans into orbit again by 2014, and manned Lunar mission by 2018.   It removes the delays which would add significant political risks.

I can't really see it as anything other than a win-win.   The only disappointment I can see is that Horowitz's Stick launcher doesn't get built.

And all of that can happen for about same cost as developing just the Ares-I & the EDS.   It would save the entire cost for developing Ares-V (which has always been a separate cost to the EDS BTW).

Ross.
Title: Re: DIRECT v2.0
Post by: CFE on 06/13/2007 04:52 AM
I'm beginning to think that developing a manned Atlas or Delta alongside Jupiter isn't as good an idea as I used to think it was.  While I'd hope that a manned EELV would be ready to launch before Jupiter 120, it would create a temptation among members of Congress to cancel Jupiter and keep us stuck in LEO.

Conversely, if Congress is committed to preserving the shuttle infrastructure and jobs (and votes,) does it really make sense to fund the man-rating of the EELV's in addition to a shuttle-derived launcher?  I don't think the marginal costs of maintaining a manned EELV alongside Jupiter are that substantial (the basic EELV's will be sustained in any event by DoD and NASA, and man-rating will likely be funded by Bigelow or other private firms,) these costs are still non-zero.
Title: Re: DIRECT v2.0
Post by: Jorge on 06/13/2007 05:35 AM
Quote
kraisee - 12/6/2007  3:06 PM

From there, you have the EELV launcher doing the 20mT CEV-only flights, and you *also* retain the 100,000+ STS workers around the country, now gainfully employed by the Jupiter Program which is - by then - half way to achieving Lunar missions.

Ross.

Where'd you get that number? According to the CAIB report, the total shuttle workforce - NASA *and* contractors combined - was around 17,000 in 2002. And I doubt it's grown by a factor of six since then.
Title: Re: DIRECT v2.0
Post by: on 06/13/2007 06:15 AM

Quote
CFE - 12/6/2007  11:52 PM  ... While I'd hope that a manned EELV would be ready to launch before Jupiter 120, it would create a temptation among members of Congress to cancel Jupiter and keep us stuck in LEO.  ...
Exactly the danger.

Quote
Conversely, if Congress is committed to preserving the shuttle infrastructure and jobs (and votes,) does it really make sense to fund the man-rating of the EELV's in addition to a shuttle-derived launcher?  I don't think the marginal costs of maintaining a manned EELV alongside Jupiter are that substantial (the basic EELV's will be sustained in any event by DoD and NASA, and man-rating will likely be funded by Bigelow or other private firms,) these costs are still non-zero.
There would be a tendency to play them off against one and another. It would depend on how quickly a lunar or Mars program would develop around the Jupiter or Ares V or whatever.

If the EELV CLV got typecast as primarily the "ISS visit vehicle", much in the same way Soyuz is, this might not be a problem, because clearly the EELV doesn't look like a Saturn V.

The key observation was the avoidance of cargo to the ISS with EELV. Apparently this is the hot button issue, because it can be done too easily (assume ATV on EELV). So if you're in the ISS "Progress" business, then Congress will ask, why can't you be in the "Soyuz" side as well?

The real issue then becomes collateral to insure that there is a legit successor to the Shuttle, and that's not believable as a EELV. At a minimum, a lunar flyby would do it.

Title: Re: DIRECT v2.0
Post by: Bill White on 06/13/2007 12:52 PM
Quote
nobodyofconsequence - 13/6/2007  1:15 AM

Quote
CFE - 12/6/2007  11:52 PM  ... While I'd hope that a manned EELV would be ready to launch before Jupiter 120, it would create a temptation among members of Congress to cancel Jupiter and keep us stuck in LEO.  ...
Exactly the danger.

Quote
Conversely, if Congress is committed to preserving the shuttle infrastructure and jobs (and votes,) does it really make sense to fund the man-rating of the EELV's in addition to a shuttle-derived launcher?  I don't think the marginal costs of maintaining a manned EELV alongside Jupiter are that substantial (the basic EELV's will be sustained in any event by DoD and NASA, and man-rating will likely be funded by Bigelow or other private firms,) these costs are still non-zero.
There would be a tendency to play them off against one and another. It would depend on how quickly a lunar or Mars program would develop around the Jupiter or Ares V or whatever.

If the EELV CLV got typecast as primarily the "ISS visit vehicle", much in the same way Soyuz is, this might not be a problem, because clearly the EELV doesn't look like a Saturn V.


Using EELV as an alternate ISS crew taxi is a good idea (in my opinion) but if that vehicle is to be competitive/comparable with Soyuz, it will need to be smaller than a full sized CEV. Let LM man-rate Atlas V using enhanced COTS funding and Bigelow as their source of demand and funding  (Boeing too if they can accept those price points for their Delta line) but put the CEV on Jupiter.

But keeping CEV "too big" for routine ISS work would also help keep Jupiter as a Moon-Mars focused launch system and avoid the temptation to use more capable Moon-Mars systems for the less demanding LEO missions.

No need to drive the Cadillac to the corner grocery.

Jupiter 120 also has the lifting power to add functions/ mass to CEV. If CEV is required to be EELV launchable, that capability becomes less available.

Title: Re: DIRECT v2.0
Post by: SolarPowered on 06/13/2007 06:14 PM
To muddy up the ISS taxi discussion a bit, I'll point out that there is an actual, committed, funded program to use the Falcon 9/Dragon as an ISS taxi.  I agree that it's quite speculative at this point whether they'll make it work, but the vehicles are actually in development, and launches have been manifested.
Title: Re: DIRECT v2.0
Post by: NotGncDude on 06/13/2007 06:47 PM
Quote
SolarPowered - 13/6/2007  2:14 PM

To muddy up the ISS taxi discussion a bit, I'll point out that there is an actual, committed, funded program to use the Falcon 9/Dragon as an ISS taxi.  I agree that it's quite speculative at this point whether they'll make it work, but the vehicles are actually in development, and launches have been manifested.

(...grumble...) And RPK's K1...
Title: Re: DIRECT v2.0
Post by: on 06/15/2007 05:52 AM

Quote
Bill White - 13/6/2007  7:52 AM But keeping CEV "too big" for routine ISS work would also help keep Jupiter as a Moon-Mars focused launch system and avoid the temptation to use more capable Moon-Mars systems for the less demanding LEO missions.