Author Topic: ASAP claim NASA is employing indecision to allow for roadmap flexibility  (Read 196583 times)

Offline Proponent

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.

Remember that Americaspace article where the gentlemen from the SLS program said their thinking is "Keep it Simple, Stupid"?  More launches, less simple.

Sure, all other things being equal, fewer launches is better.  But all other things aren't equal.  For one thing, a smaller vehicle which flies more often will tend to be more reliable than a larger one which flies infrequently*.  And the very low launch-failure rate that ISS has suffered suggests that relying on many launches need not be a huge problem.

My major point here, though, is not to argue that one is necessarily better than the other, but to point out that the trade studies must be performed, and that outcomes will be affected by flight rate, with an HLV looking better if there's enough demand to keep it flying several times per year.  If you're going spend many billions developing an HLV, you'd better justify it.  That hasn't happened.



*And all of the advanced Orion/SLS missions proposed by NASA in recent conops documents require three SLS launches anyway.  That's actually a pretty big Achilles' heal when you think about it.  With only one pad available, that means such missions will have to be assembled in orbit over an 8-month period, and any one launch failure will be catastrophic.  Suppose a similar mission were to be mounted with launch vehicles of about 50 tonnes' capability.  As the Augustine report notes, with launch vehicles of that size, no more than three "critical" launches (those carrying expensive hardware) are needed.  All the rest are propellant, which is cheap: if a launch fails, it's conceivable you could arrange a back-up launch.  Hence, the risks need not be any greater than for the SLS approach.
« Last Edit: 03/10/2014 09:40 am by Proponent »

Offline Proponent

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Many NASA studies would disagree, and there was an MIT study that just came out this week that showed how fuel depots could greatly enhance our ability to go places in space (local space for sure).

Would you have a link or hint as to where to find it?

Offline Jim

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.


We don't have the terrestrial capability to handle payloads larger than 5 meters and 20 tonnes.  The industrial infrastructure doesn't support larger payloads.  Not at Denver, Dulles, Sunnyvale, El Segundo, Redondo Beach, Palo Alto, Pasadena, Greensbelt, Gilbert, Boulder, etc where all spacecraft manufacturers are located.

Offline muomega0

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.
We don't have the terrestrial capability to handle payloads larger than 5 meters and 20 tonnes.  The industrial infrastructure doesn't support larger payloads.  Not at Denver, Dulles, Sunnyvale, El Segundo, Redondo Beach, Palo Alto, Pasadena, Greensbelt, Gilbert, Boulder, etc where all spacecraft manufacturers are located.

CNYMike:  numbers, studies, and references?

Automated Rendezvous and Docking Risk
A key flaw in ESAS was  "The goal of the analysis was to eliminate all “3-launch solutions” and better optimize each of the mission mode options" based on 1.5% chance of catastrophic AR&D failure, which does not reflect decades of actual experience.

Then NASA violates the 3 launch mission goal with Mars DRM 5 with Ares V--five, no six flights due to boiloff.

Q:  Why not spend resources on the {artificially} high AR&D risk?  A SpaceX berthing has a 1.5% chance  of catastrophic AR&D failure?
 
Myth: Fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.

From the JSC depot study
Quote
* This study does not support the perception that depots add an unacceptable level of risk and should not be considered due to the increased number of launches, AR&Ds, and transfers.
* Reduces risk of LOM by decoupling propellant delivery flights from delivery of mission elements (i.e., elements stay on the ground until needed for mission)

Offline JohnFornaro

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So depots do not change when a mission to a given destination has to get under way.  And that is determined by where the mission is going.  Some things have to be determined; you can not just go "wherever whenever."  How often you can go to a given destination is determined by celestial mechanics, not whether there's a fuel depot sitting somewhere.

Maybe they don't change how often you can leave for destinations far away, but depots are part of the architecture that ensures that you can make your celestially-driven departure dates.

NASA has met "celestial driven departure dates" for decades without magic depots.

That is certainly true in a technical sense, but it overlooks completely the pragmatic value of being able to top off the tank from a depot.  Prop could be stored up there, multiple vehicles could fill up and take advantage of a common launch window.  Unmanned launches could take place over several months, and a fleet could be launched from that L-point, within some few hours of the crew arriving.

In that sense, we could leave for destinations "more often".  It's not just about celestial mechanics, it't mostly about sending enough people, habs, tugs, EDL craft, and so forth.

Quote from: Mike
Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.

This meme is way overplayed.  20 ton chunks is a great starting point, with ISS as the prime example. 

Still, while it is true that smaller modules means more risk in some narrowly defined mathematical sense, which does not consider cost schedule, pragmatics and a host of related issues, right now we have zero modules and literally no risk.  Which is kind of interesting in a tragi-comic sort of way. 

Also lost in your BOTE rendition of the SLS knee-jerk risk equation is that losing one 130 ton module is worse than losing one out of about six twenty ton modules.  Either all LV's have the same risk of loss, or else there is something wrong with the risk equation.  Put another way, all other things are not equal, between the two launch techniques.

Finally, if on-orbit assembly, a technique which has been continually demonstrated now for decades, is now suddenly to be abandoned as a pragmatic tactic for implementing the strategy of enabling a permanent human presence BLEO, particularly such a presence on the red planet, then it must be accepted that the larget module landed up there will not exceed 20 tons itself.

So the non-cognitively dissonant analyst will ask: What law of physics is it such that 20 tons in LEO is bad, but 20 tons on Mars is good?

None of the above argues at all that the principle of fewer larger chunks is in general, a good thing.  That's why the 130 ton SLS variant would serve well as an unmanned cargo LV.  But hey.  They're not after reasoned accomplishment.
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.


We don't have the terrestrial capability to handle payloads larger than 5 meters and 20 tonnes.  The industrial infrastructure doesn't support larger payloads.  Not at Denver, Dulles, Sunnyvale, El Segundo, Redondo Beach, Palo Alto, Pasadena, Greensbelt, Gilbert, Boulder, etc where all spacecraft manufacturers are located.

Well then, they should up the throw weight of SLS to 150 tons ASAP, to take advantage of the infrastructure, don't ya think?
Sometimes I just flat out don't get it.

Offline HappyMartian

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.


We don't have the terrestrial capability to handle payloads larger than 5 meters and 20 tonnes.  The industrial infrastructure doesn't support larger payloads.  Not at Denver, Dulles, Sunnyvale, El Segundo, Redondo Beach, Palo Alto, Pasadena, Greensbelt, Gilbert, Boulder, etc where all spacecraft manufacturers are located.


"Vestas Wind Systems has been at the heart of the wind industry’s development across the world and continues in that role with the development of its V164 platform, which is not only on track for prototype deployment but has recently seen a technological development allowing the turbine to now reach a capacity of 8 megawatts!"

And, "The development of the new V164 turbine is progressing according to schedule, with several main components currently nearing completion:
    The blade mould for the 80-metre blades is ready at Vestas’ testing facilities on the Isle of Wight, UK, and the production of the first blade for testing purposes will be initiated during Q4."

From: Gamechanging Vestas V164 Wind Turbine Continues Groundbreaking Development (8MW Wind Turbine!)
At: http://cleantechnica.com/2012/10/03/gamechanging-vestas-v164-turbine-continues-groundbreaking-development-8mw-wind-turbine/


The wind power folks have repeatedly upgraded and can now handle 80-meter long blades and put together enormously large onshore and offshore wind generators.

Perhaps "technological development" sometimes means building much bigger pieces of technology.

Upgrade the payload handling infrastructure.

Or perhaps the folks in the White House would simply prefer instead to offshore Lunar and Mars mission technology to Russia, China, and India? Yep, let's offshore everything! 
"The Moon is the most accessible destination for realizing commercial, exploration and scientific objectives beyond low Earth orbit." - LEAG

Offline Coastal Ron

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Many NASA studies would disagree, and there was an MIT study that just came out this week that showed how fuel depots could greatly enhance our ability to go places in space (local space for sure).

Would you have a link or hint as to where to find it?

Here is an article on Gizmag that talks about it, and provides a link to the paper - which is behind a paywall.
http://www.gizmag.com/mit-space-gas-station/31126/
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Jim

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"Upgrade the payload handling infrastructure. "

Another post showing lack of understanding.   It isn't handling, is test facilities.

Offline JohnFornaro

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Isn't if great how all these rocket scientists insist that we just gotta have a 130 ton SLS, even tho we can only handle 20 tons at a time?  Sheesh.
Sometimes I just flat out don't get it.

Offline JohnFornaro

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Probably, on-pad manned assembly is less risky than unmanned in-space assembly.

Just tryin' to find the silver lining...
Sometimes I just flat out don't get it.

Offline R7

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I'm stuck wondering what 80meter wind mill blade has to do with this thread.
AD·ASTRA·ASTRORVM·GRATIA

Offline CNYMike

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Maybe they don't change how often you can leave for destinations far away, but depots are part of the architecture that ensures that you can make your celestially-driven departure dates.
NASA has met "celestial driven departure dates" for decades without magic depots.  Just look at any spacecraft on or orbiting Mars.  Curiosity had a very specific departure time not just to reach Mars but land at a specific spot.  Made it.  No depot.  Whatever their advantages, that's one of them.

Uh, those were all missions where everything that was needed for the mission flew on one launch (and pretty small hardware too).  Are you saying that the roadmap for exploration that NASA is working on will never rely on more hardware than what can fit on one rocket?


No, I am saying those mission did not need a depot to "ensure" they made "celestial driven departure dates."
Quote
.... You are aware that NASA plans on using modular construction and in-space refueling with the SLS in order to go to Mars, right?  It's not a nice to have, it's mandatory if we're going to go to Mars in any meaningful way.

Which means refueling, assembly, and the SLS are not mutually exclusive, even though SLS opponents act like they are.
Quote
"Assembly" does not equal "depot."  Nor does in orbit fueling up require it. 

We have over 13 years of doing both with the ISS, and it makes no sense to do one but not the other.

And still no depot involved.  I am responding to the notion that depots are the be-all-and-end-all, necessary to architectures.  You keep pointing to examples where they are not used. 
Quote
Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.

Bigger is not always a magic solution, especially when you have to give up flexibility to get it.  What's important is to pick the size that the entire "ecosystem" can support.  As of today that is the 5m diameter family of payloads that are less than 20mt in mass.  We have real data on how this architecture works, and ZERO on SLS-sized ones.

You forgot about Skylab.  I have a hunch it was bigger than those parameters, and probably what the guys behind the Skylab II study have in mind.

Quote
Remember that Americaspace article where the gentlemen from the SLS program said their thinking is "Keep it Simple, Stupid"?  More launches, less simple.

......As to KISS, that would be what we have today, not mythical architectures that have unproven value or need.

Your existing-rockets-and-depots architectures are just as mythical at this point.
« Last Edit: 03/10/2014 04:56 pm by CNYMike »
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Offline CNYMike

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.


We don't have the terrestrial capability to handle payloads larger than 5 meters and 20 tonnes.  The industrial infrastructure doesn't support larger payloads.  Not at Denver, Dulles, Sunnyvale, El Segundo, Redondo Beach, Palo Alto, Pasadena, Greensbelt, Gilbert, Boulder, etc where all spacecraft manufacturers are located.

Tell the guys who did Skylab II.
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Offline Lars_J

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.


We don't have the terrestrial capability to handle payloads larger than 5 meters and 20 tonnes.  The industrial infrastructure doesn't support larger payloads.  Not at Denver, Dulles, Sunnyvale, El Segundo, Redondo Beach, Palo Alto, Pasadena, Greensbelt, Gilbert, Boulder, etc where all spacecraft manufacturers are located.

Tell the guys who did Skylab II.


Does Skylab II exist outside of powerpoint?

Online Galactic Penguin SST

Maybe they don't change how often you can leave for destinations far away, but depots are part of the architecture that ensures that you can make your celestially-driven departure dates.
NASA has met "celestial driven departure dates" for decades without magic depots.  Just look at any spacecraft on or orbiting Mars.  Curiosity had a very specific departure time not just to reach Mars but land at a specific spot.  Made it.  No depot.  Whatever their advantages, that's one of them.

Uh, those were all missions where everything that was needed for the mission flew on one launch (and pretty small hardware too).  Are you saying that the roadmap for exploration that NASA is working on will never rely on more hardware than what can fit on one rocket?


No, I am saying those mission did not need a depot to "ensure" they made "celestial driven departure dates."
Quote
.... You are aware that NASA plans on using modular construction and in-space refueling with the SLS in order to go to Mars, right?  It's not a nice to have, it's mandatory if we're going to go to Mars in any meaningful way.

Which means refueling, assembly, and the SLS are not mutually exclusive, even though SLS opponents act like they are.
Quote
"Assembly" does not equal "depot."  Nor does in orbit fueling up require it. 

We have over 13 years of doing both with the ISS, and it makes no sense to do one but not the other.

And still no depot involved.  I am responding to the notion that depots are the be-all-and-end-all, necessary to architectures.  You keep pointing to examples where they are not used. 
Quote
Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.

Bigger is not always a magic solution, especially when you have to give up flexibility to get it.  What's important is to pick the size that the entire "ecosystem" can support.  As of today that is the 5m diameter family of payloads that are less than 20mt in mass.  We have real data on how this architecture works, and ZERO on SLS-sized ones.

You forgot about Skylab.  I have a hunch it was bigger than those parameters, and probably what the guys behind the Skylab II study have in mind.

Quote
Remember that Americaspace article where the gentlemen from the SLS program said their thinking is "Keep it Simple, Stupid"?  More launches, less simple.

......As to KISS, that would be what we have today, not mythical architectures that have unproven value or need.

Your existing-rockets-and-depots architectures are just as mythical at this point.

Chuck have been advocating exactly this with the DIRECT plans several years ago....  ::)
Astronomy & spaceflight geek penguin. In a relationship w/ Space Shuttle Discovery. Current Priority: Chasing the Chinese Spaceflight Wonder Egg & A Certain Chinese Mars Rover

Offline Jim

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Tell the guys who did Skylab II.



They did nothing but pretty drawings

Offline muomega0

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Bigger modules, fewer launches, less time and risk on on-orbit assembly.  Smaller modules, more launches, more risk.

Bigger is not always a magic solution, especially when you have to give up flexibility to get it.  What's important is to pick the size that the entire "ecosystem" can support.  As of today that is the 5m diameter family of payloads that are less than 20mt in mass.  We have real data on how this architecture works, and ZERO on SLS-sized ones.

You forgot about Skylab.  I have a hunch it was bigger than those parameters, and probably what the guys behind the Skylab II study have in mind.

Remember that Americaspace article where the gentlemen from the SLS program said their thinking is "Keep it Simple, Stupid"?  More launches, less simple.

......As to KISS, that would be what we have today, not mythical architectures that have unproven value or need.

Your existing-rockets-and-depots architectures are just as mythical at this point.
CNYMike:  numbers, studies, and references?

Mythbuster Checklist:
                               SLS          Depots
Development Costs     50B           10 time less
130 mT per year          2B           0.5B

the depot is an upper stage with stretched tanks and no engines.
With decades of experience, and all the new friction welders, no concern here.
now add a power system, a refrigeration system, attitude control and rotation.

Depot Tanks:          Same as SLS upper stage or stretched
Power System:       Smaller than ISS
Attitude control:     Many options with experience
AR&D                    Many options including berthing
Cryocoolers:          Demonstrated and scalable at the correct We/Wt
Gas/Fluid Sep:        Rotate the depot:  demonstrated  other options under R&D
Fluid Transfer:        With gas/fluid separated, just like on the ground
Passive Design:      Can include ULA's passive LH2 boiloff concept to maintain LOX to ZBO for contingency

In summary, you repeat the ESAS flaws with no data or references, many of the core elements are common with the SLS transfer stage, and the unique components just needs $$ to raise the TRL level--no showstoppers.

Of course, i hear that Spacex is building a one shot Mars rocket that should be able to send crew to the L2 Gateway and conduct lunar missions at the very least.   Wow, both ULA and SLS may be outta business soon if NASA goes with the cheaper LV HLV architecture with no depots.  Since GCR shielding has not been addressed this would make HappyMartian happy as NASA would head back to lunar with a HLV-- or does  HM only support back to lunar with SLS and H2O2 and AlH3?  Comments HM?

Offline CNYMike

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Tell the guys who did Skylab II.



They did nothing but pretty drawings

Point is they didn't think building something on that scale was impossible.

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Offline CNYMike

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Mythbuster Checklist:

Number of depots actually assembled and operating at this point:  none. 

Quote
Of course, i hear that Spacex is building a one shot Mars rocket that should be able to send crew to the L2 Gateway and conduct lunar missions at the very least ....

When their web site starts promoting it, I'll believe it.  I checked.  It's not.

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Michael Gallagher
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