Author Topic: NASA Study Shows Cheaper Alternatives to SLS  (Read 79353 times)

Offline Jim

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #40 on: 10/13/2011 10:29 PM »


1.  I'm a little confused by the Depot Study power point, it seems that a major cost of the depot is getting the fuel into space, is there a technical reason why SLS can't fly fuel. 

2.  Further, it would be useful to see how the cost were derived, I suspect a series of assumptions about the cost for development of the Falcon 9 heavy includes a SpaceX provided system and infrastructure at no cost to NASA,

3.   also that the SLS will have to cost the same as STS - why?

4.  Also the SLS costs appear to include full burden (quite reasonable) but is this true of Falcon 9 heavy and Delta heavy? Full burden includes, if I'm not mistaken the cost for MSFC and HSFC - the people who will run the missions and must be included as part of the NASA HSF program.

1.  It does in its own upperstage.  Depots eliminate the need for a large launcher by spreading the propellant over multiple launches

2.  Correct, commercial launcher development is at no cost to NASA

3. it uses shuttle legacy systems

4. No, SLS is a NASA run system so NASA is burden with all its costs.  With commercial launch services, NASA only pays for the launch of its spacecraft.

Offline jongoff

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #41 on: 10/13/2011 10:35 PM »
An interesting observation a friend pointed out.  The depot study, which was performed by NASA on an apples-to-apples basis vs. an SLS-centric approach, showed that the depot-centric approach could stay below the budget target even in a rougher economic situation.  My friend noted though that things were far enough below the budget bogey that it looked like there would be room to pull the schedule significantly to the left.  Looking at the numbers, it looks like we could have a return to the moon by 2021, if we had gone the depot route, instead of some time in the late 2020s/early-to-mid 2030s with SLS.

Missed opportunities.

~Jon
wow
would it be possible to get a copy of the study for L2?

I don't know about the underlying study, I was just talking about the public results. 

~Jon

Offline Jim

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #42 on: 10/13/2011 10:39 PM »
And multiple types of launch vehicles could be used: Delta IV Heavy need not shoulder the entire burden.

Absolutely.  Complexes 37B, 40, and 41 lined up at the Cape could handle eight launches between them in a year and probably still do their normal business, which during the past 12 months has amounted to only three each from 37B and 41 and one from 40.
 
 - Ed Kyle
I must call you on this Ed.  The Atlas only needs a few hours on-pad, and Delta will have similar pad demands at the end of it's current upgrade cycle.  Delta needs weeks of processing as it is, but most of that is not on the pad, but in the processing facility.  Atlas, by comparison, arrives at the cape already set up.  According to the documents I have here, the Delta pad can handle as it is now 1 Delta IV Heavy every 6 weeks, and the Atlas launch site could handle an Atlas launch every other week at current staffing levels.  Add in the option to build out 37A and the use of VAFB, the two EELV's can handle a much higher flight rate than the current demand without additional staffing needs.  But if flight rate increases, more staff would be added to compensate.

Both Delta and Atlas already use a mobile platform, which undermines your argument.

Incorrect.

Atlas is running at its max capacity for the existing manpower 4- 6 missions per year, depending on use of SRB's on each mission.  With more manpower, it can go to 8 to 12 per year, after that a new VIF is needed.   It takes more than two weeks to stack and test an Atlas so that it is ready for the payload.  Also, there is a WDR.


Delta  does not have a mobile platform.  Heavy takes longer than 6 weeks.  It does not do any electrical testing until it is at the pad.

4 mediums per year with current manning
« Last Edit: 10/13/2011 10:40 PM by Jim »

Offline BrightLight

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #43 on: 10/13/2011 10:43 PM »
And multiple types of launch vehicles could be used: Delta IV Heavy need not shoulder the entire burden.

Absolutely.  Complexes 37B, 40, and 41 lined up at the Cape could handle eight launches between them in a year and probably still do their normal business, which during the past 12 months has amounted to only three each from 37B and 41 and one from 40.
 
 - Ed Kyle
I must call you on this Ed.  The Atlas only needs a few hours on-pad, and Delta will have similar pad demands at the end of it's current upgrade cycle.  Delta needs weeks of processing as it is, but most of that is not on the pad, but in the processing facility.  Atlas, by comparison, arrives at the cape already set up.  According to the documents I have here, the Delta pad can handle as it is now 1 Delta IV Heavy every 6 weeks, and the Atlas launch site could handle an Atlas launch every other week at current staffing levels.  Add in the option to build out 37A and the use of VAFB, the two EELV's can handle a much higher flight rate than the current demand without additional staffing needs.  But if flight rate increases, more staff would be added to compensate.

Both Delta and Atlas already use a mobile platform, which undermines your argument.

Incorrect.

Atlas is running at its max capacity for the existing manpower 4- 6 missions per year, depending on use of SRB's on each mission.  With more manpower, it can go to 8 to 12 per year, after that a new VIF is needed.   It takes more than two weeks to stack and test an Atlas so that it is ready for the payload.  Also, there is a WDR.


Delta  does not have a mobile platform.  Heavy takes longer than 6 weeks.  It does not do any electrical testing until it is at the pad.

4 mediums per year with current manning

How many people does it take to run 4 to 6 Atlas LV and How many people does it take to launch 4 Delta medium/heavy?

Offline oldAtlas_Eguy

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #44 on: 10/13/2011 10:54 PM »
One interesting thing when trying to create the same capable Lunar mission using SLS that was referenced in the Depot presentation is that the Depot presentation was using the propelants and dry weights used for a Ares V Lunar mission. So a SLS comparable mission using a single launch is not possible because the reference mission hat the Depot missions were created from uses an equivelent 220MT LEO HLV. To do the same with SLS will require depot technology since multiple launches of SLS would be required.

Offline Lobo

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #45 on: 10/13/2011 10:57 PM »


Haven't we cleared this up yet?  The 1 flight every 12-18 months is a WORSE case scenario...

No, we most certainly haven't. And the scenario you're thinking of is one launch every 24 months, anyway. Some people think that's the 'worse case scenario,' some others do not. Without additional funding the one flight every 12-24 months is quite the realistic assumption. With additional funding, a launch every year could be done, but it looks like Congress is leaning towards cutting NASA instead of increasing their budget.

Ahhhhh...reminds me of the old "Less filling!"  vs. "Taste great!" commercials for Lite Beer from Miller.  Ahhh....good times.

Well, about all that is clear, is that the EELV proponets will forever keep claiming that there's no money for for more than one SLS every couple of years with payload.  And the SLS proponents will forever claim that there is.  Unfotunately we'll have to wait awhile before we find out if there is or not, right now, we're all pretty much guessing.

However, I will throw out a little historical perspective to back why I think there will be money for an "ok" flight rate, and payloads.

First, I think it's pretty likely that the annual operation costs and per flight launch of SLS will be pretty close to STS.  After all, the cores will cost about the same to build as the ET.  The 5-seg boosters might be a little more than the old 4-seg, but apparently ATK gave NASA a pretty good deal on them so they could at least sell -some-, and try to position for the full SLS contract.  Once RS25E's are rolling off the line, I imagine their cost per unit will be pretty similar to the RS25D's with their incredibly low production rate/high labor costs, and refurb costs.
That leaves The orbiter refurb costs vs. Orion CSM costs per launch.  Maybe Orion will be a little more, maybe a little less.  We'll call it a wash for this exercise.  (non-crewed launches would not have the Orion costs, and thus should be cheaper than STS, but we'll include it for an apples-to-apples comparison of crew + payload).

So, for around 30 years, NASA had the funds to light the Shuttles off at a clip of around 4-5 per year average, more or less.  They also had the money to put payloads on all of those Shuttles.  Some were DoD payloads in the early days I guess, but most after Challenger were NASA or international partners I believe (correct me if I'm wrong).  During the 90's and 2000's, there was enough money for that launch rate, plus several VERY expensive ISS components.  In fact, other than the two Russian modules, the 1.5 JAXA modules, and the one ESA module, NASA paid for everything else I believe.
And those were not cheap payloads.  Ditto with Hubble, and each of the very expensive Hubble repair missions.

I'm no expert on these things, but I think today's NASA buget is roughly about the same as it was during that time, when adjusted for inflation (again, correct me if that's wrong), and has been fairly stagnant for some time now, only getting basically "cost of living" increases over the past several years. 

So, I'm going to go out on a limb her and say that once SLS has been developed, there will be money for at least a couple of launches a year, and payloads for them.  :-)  Seems pretty obvious.

Now that sort of depends on the payloads.  If they are trying to launch 100mt of gold bullion into LEO, then that might eat into NASA's budget quite a bit.  On the other hand, if they are doing a Lunar flyby, you aren't maybe for much behind the LV itself. 

I think the mistake a lot of people make is assuming that a)  SLS can only launch with a maximum payload, and b)  that if SLS can launch 4 times what STS could, and the STS paylaods were $X dollars, then every paylaod for SLS will be 4 x $X dollars.  So in other words, 1 SLS launch with payload will cost about the same as 4 STS launches.  Thus while we found the money to launch 4 STS's per year, we'll be luck to get one SLS up per year.
Does that pretty much sum up that argument?
Well it's inaccurate on both counts.
First, you can launch SLS anywhere from fully loaded to friggin empty if you want.  IF you have a 40mt payload, SLS can be launched with that perfectly fine.  STS was a HLV that could only launch ELV class payloads.  So you could launch 4 or 5 ELV class payloads on 4 or 5 SLS launches per year if you want.  Remember, your LV cost is about the same if you are launching it full or partially empty.
Secondly, a payload 4 times the size of an ELV/STS payload isn't necessarily going to cost 4 times what the average ELV/STS payload has.  It's a case by case basis.  Some will go up proportionally, or even expoentially with size, and thus be cost prohibitive to do large enough to fully utilize SLS, and they'll stick with EELV's.  But some won't.  SLS being available might just mean that the next planetary probe or satilite with just have far larger fuel tanks, and thus a much longer operational life.  Everyone always said fuel is the cheapest part, so you could put 4 times as much fuel on that probe, so it could do many more course corrections during it's life, or just get to the target faster, and not add much cost to that mission. 

Or maybe the payload could actually be made -cheaper- by being made -bigger- in the sense it could be made with better safety margins, a more robust design, and made out of cheaper, less exotic materials.  Aluminum instead of high-tech composits.  Thicker alloy fuel tanks instead of high-tech filiment wound tanks.  Large [heavy] solar panels instead of a radio isotope power source for operating farther out int he solar system with solar power than we usually do.  Having a single, wide mirror on a space telescope instead of some funky segmented one that has a complex deployment mechanism that adds a lot of costs to fit into a smaller PLF and LV.  Etc etc.

So larger can sometimes just mean more simple and reliable, rather than more expensive.  AGain, that won't apply to every payload, each payload will be different, and some will need to be smaller and utilize the cheaper EELV's.  But it will apply to some payloads.

So, here's my position until I see something concrete to the contrary.
1)  There will be enough money and payloads to keep SLS launching at a clip of around 2 per year once it's flying and proven and people can starting planning for it's capability (something they won't do now since it doesn't exist, and can always be cancelled). 

2)  An all EELV approach, evolving into wider body upper stages and boosters (like FX or AVP2) would likely be the cheapest and best way to go forward in a perfect world, were engineers ran everything, and unicorns frollicked in fields of gums drops and rainbows.  Unfortunately, that world is not the REAL world.  NASA is a government agency, and subject to goverment politics.  All EELV was looked at and rejected, probably due mainly to political reasons.  Fingers were probably put on scales to spin it so it seemed like SLS was really the cheapest and most efficient option, because that was the outcome that the power brokers wanted.  So they changed the goal posts to make that the winner.
People can cry a river about it, but welcome to life!  Life ain't fair.  Deal with it.

If I thought the politics would change anytime soon to get SLS cancelled and all EELV greenlighted and rolling, then I'd probably be holding out for that too.  But that's unlikely, and the most likely scenario would be for SLS to be put on hold and have another several years of political wrangling.  Meanwhile, NASA lays even more people off.

So that's why, at this point, I'm coming down on the side of rolling with SLS, even though I think AJAX would have been better, as would have all EELV.  But SLS is what we have.  It's a political compromise rocket.  Not nearly as good as an actual engineer rocket, but it's what we have, and it should work ok, even if it's not the perfect LV.

 
« Last Edit: 10/13/2011 11:14 PM by Lobo »

Offline Lobo

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #46 on: 10/13/2011 11:08 PM »

But not all those STS flights had payloads of the dollar value that would be required by BEO HSF payloads. I can't speak to the motivations of Political Hack Wannabe who may or may not be being disingenuous, but it's clearly fair to say that money spent on SLS is money that can't be spent on payloads.


That a moot point.  Money spent on buying EELV's from ULA is money that can't be spent on payloads either.  Money that was spent on SLS was money that couldn't be spent on payloads.  Etc. Etc.  You actually do need to buy the LV's before you can worry about putting something on top of it.



This is the second study (the first being the Doug Stanley/Georgia Tech one) that has shown that depots+EELV-class rockets are cheaper than SLS by a factor of roughly two. Granted, this is for a small range of DRMs (DRM3, IIRC, for the Stanley one), but it's getting harder to believe that there's any mission+architecture+flight-rate out there that really can be cheaper via SLS.


Again, that's all great in the world of lollipops and unicorns.  But NASA seemed to want their own rocket, and Congress seemed to want NASA to have their own rocket.  NASA is a government agnecy, so poof...you have SLS.  All EELV was looked at during the RAC evaluation.  It might have gotten 86'd for political reasons rather than real cost or technical reasons, but it got 86'd nonetheless.  IT doesn't help if all EELV would be half the LV price of SLS, if that plan never gets approved, does it?

If you think you can get Congress to issue a new authorization act, trumping NAA2010, and wiping the slate clean for NASA to use whatever LV it wants, with absolutely not heritage or politcal criteria whatsoever, be my guest.  :-)

Otherwise, I think it's time to get off the sidelines and start getting behind the program...as unperfect is it might be.

IMHO....

Offline Robotbeat

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #47 on: 10/13/2011 11:28 PM »

But not all those STS flights had payloads of the dollar value that would be required by BEO HSF payloads. I can't speak to the motivations of Political Hack Wannabe who may or may not be being disingenuous, but it's clearly fair to say that money spent on SLS is money that can't be spent on payloads.


That a moot point.  Money spent on buying EELV's from ULA is money that can't be spent on payloads either.  Money that was spent on SLS was money that couldn't be spent on payloads.  Etc. Etc.
You buy launch services, not a launch vehicle from ULA. And it's far less money than SLS, both individually and for a total mission. It's not a moot point, because if you run out of money and get the whole thing canceled after building the payload but before launching it, you can mothball the payload and fly it pretty quickly after receiving enough funds at a later time. If you develop SLS and run out of money and get the whole thing canceled before you start developing the payloads, you have to essentially scrap the whole thing (minus saving some engines, maybe) because it's not really feasible to mothball a whole launch vehicle and all its launch infrastructure without some serious cash, so if it's reinstated you have to start almost from scratch.

Quote
You actually do need to buy the LV's before you can worry about putting something on top of it.
No, you don't. You can start developing a payload for, say, an Atlas V long before you pay ULA for its launch. Again, you're thinking about it bass-ackwards. Rockets exist for their payloads, not payloads for the rockets.
« Last Edit: 10/13/2011 11:34 PM by Robotbeat »
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Offline Robotbeat

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #48 on: 10/13/2011 11:38 PM »
One thing that hit me about the proposal: CPS can function as a depot (or possibly vice versa). It is essentially a payload, and could be used for many different kinds of missions and could be launched by different types of launch vehicles.... Which is really essential in a world where you can have a launch vehicle stand-down for a while or when one of those launch vehicles doesn't exist (and thus should not be completely relied upon).

It can get support from many different folks, and should be built (at least as a tech demo) as soon as possible.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline oldAtlas_Eguy

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #49 on: 10/13/2011 11:52 PM »
One thing that hit me about the proposal: CPS can function as a depot (or possibly vice versa). It is essentially a payload, and could be used for many different kinds of missions and could be launched by different types of launch vehicles.... Which is really essential in a world where you can have a launch vehicle stand-down for a while or when one of those launch vehicles doesn't exist (and thus should not be completely relied upon).

It can get support from many different folks, and should be built (at least as a tech demo) as soon as possible.

Yes the technology needed here minus the fuel transfer capability for a CPS that would have a wet weight ~120MT, would enable a great many possibilities for SLS missions. Then also the same technology and hardware with the added transfer capabilities is in actuality a Depot and would enable the same missions even without SLS.

Offline Robotbeat

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #50 on: 10/14/2011 12:04 AM »
One thing that hit me about the proposal: CPS can function as a depot (or possibly vice versa). It is essentially a payload, and could be used for many different kinds of missions and could be launched by different types of launch vehicles.... Which is really essential in a world where you can have a launch vehicle stand-down for a while or when one of those launch vehicles doesn't exist (and thus should not be completely relied upon).

It can get support from many different folks, and should be built (at least as a tech demo) as soon as possible.

Yes the technology needed here minus the fuel transfer capability for a CPS that would have a wet weight ~120MT, would enable a great many possibilities for SLS missions. Then also the same technology and hardware with the added transfer capabilities is in actuality a Depot and would enable the same missions even without SLS.
Right, it's something that everyone could rally around. It'd also work just about as well if SLS never gets a true upper stage (if it could be refueled), and it could work well to refuel a reusable lunar lander (it could either launch itself to lunar orbit on an efficient ballistic trajectory or be towed there full by a SEP tug... the ultra-low-boiloff capability needed for Mars would make that feasible... and, of course, the SEP tug could almost as easily tug the thing all the way to Mars or wherever).

I guess the only drawback is that it has a high dry mass.
« Last Edit: 10/14/2011 12:05 AM by Robotbeat »
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Offline Lobo

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #51 on: 10/14/2011 12:10 AM »

But not all those STS flights had payloads of the dollar value that would be required by BEO HSF payloads. I can't speak to the motivations of Political Hack Wannabe who may or may not be being disingenuous, but it's clearly fair to say that money spent on SLS is money that can't be spent on payloads.


That a moot point.  Money spent on buying EELV's from ULA is money that can't be spent on payloads either.  Money that was spent on SLS was money that couldn't be spent on payloads.  Etc. Etc.
You buy launch services, not a launch vehicle from ULA. And it's far less money than SLS, both individually and for a total mission. It's not a moot point, because if you run out of money and get the whole thing canceled after building the payload but before launching it, you can mothball the payload and fly it pretty quickly after receiving enough funds at a later time.


Your original point is a moon point.  But now you've changed your point.  Your original point was that money spend on SLS was money you can't spend on payloads.  But that is true for any LV, so your point is moot.
That's what I was pointing out.

That you think EELV will cost less than SLS, so that even though every dollar spent on EELV's will be a dollar you can spend on a paylaod, you will have -more- money left over to shuffled to payloads is a valid point if it's true. 


No, you don't. You can start developing a payload for, say, an Atlas V long before you pay ULA for its launch. Again, you're thinking about it bass-ackwards. Rockets exist for their payloads, not payloads for the rockets.

Chicken and egg argument.  If you have a payload without a rocket, then what good is it to you?  If you have a rocket without a payload, there's no point it launching it. One isn't necessarily the driver of the other.
Yes, the purpose of a rocket is to get the desired payload into Space.  But without it the payload's not going anywhere.  Sometimes the payload is designed for the LV available, so the rocket is the driver (STS payloads).  Sometimes the rocket is designed for the payload, so the payload is the driver (Saturn).

What payload did the shuttle exist for?

REgardless, it's a pointless debate.  Just trying to point out the other side.

Offline Robotbeat

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #52 on: 10/14/2011 12:19 AM »
BTW, under HEFT, the CPS is supposed to start development almost as soon as the HLLV (though with a far, far smaller budget). Is that still true? Does CPS include AR&D capabilities?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Chris Bergin

Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #53 on: 10/14/2011 12:28 AM »
Split the topic into a standalone thread as promised.

PS Should this be in HLV? My prop depot articles are in commercial, I think?

Offline Jim

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #54 on: 10/14/2011 12:47 AM »
The shuttle was designed around DOD and space Station payloads

Offline Jim

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #55 on: 10/14/2011 12:49 AM »

How many people does it take to run 4 to 6 Atlas LV and How many people does it take to launch 4 Delta medium/heavy?

ULA has 300 people on the cape

Offline yg1968

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #56 on: 10/14/2011 01:37 AM »
I will express my opinion on this presentation with quotes from the Scrooge. Scrooge says to The Ghost of Christmas Future:

Quote
“Men’s courses will foreshadow certain ends, to which, if persevered in, they must lead”. “But if the courses be departed from, the ends will change. Say it is thus with what you show me!” "... Why show me this, if I am past all hope!...

http://en.wikipedia.org/wiki/Ghost_of_Christmas_Yet_to_Come
« Last Edit: 10/14/2011 01:46 AM by yg1968 »

Offline sewand

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #57 on: 10/14/2011 01:48 AM »
Nice quote!

What makes this so irritating, is that this is what FY11 should have been!  If they had trotted out this, or an ACES-like architecture of propellent depots and moon landings, then it would have been something to get behind.  Instead, it was this gelatinous mass of tech demos, wishy-washy direction on HLV, and missions deferred until my children become grandparents. 
And until we actually see an SLS-based exploration plan, we probably can't say the current situation is any better.  I guess we're not quite past all hope...

Offline A_M_Swallow

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #58 on: 10/14/2011 02:10 AM »
I would like to see how a small lunar base could be operated with the Falcon Heavy.

Maybe do six month long missions (longer if the body responds well to partial gravity and if radiation shielding is good enough). Maybe a lego like lunar lander, a large version could be used for modules and cargo (on a low thrust trajectory?), smaller version for crew.

Not entirely sure how you could get cargo to the base effectively. Maybe have an unmanned vehicle that retrieves cargo vehicles from their landing site, transports and then connects them to the base.

Maybe something like the image below. And I guess that means after about ten re-supply missions, the moon would have a decent sized junkyard.

This is NASA's proposed combined crane and cargo rover - the ATHLETE.
http://www-robotics.jpl.nasa.gov/systems/system.cfm?System=11

There are some nice films in the video gallery.


p.s.  The LV and landers chosen needs to be able to land machine like this on the Moon.
« Last Edit: 10/14/2011 02:14 AM by A_M_Swallow »

Offline Namechange User

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Re: NASA Study Shows Cheaper Alternatives to SLS
« Reply #59 on: 10/14/2011 02:11 AM »
An interesting observation a friend pointed out.  The depot study, which was performed by NASA on an apples-to-apples basis vs. an SLS-centric approach, showed that the depot-centric approach could stay below the budget target even in a rougher economic situation.  My friend noted though that things were far enough below the budget bogey that it looked like there would be room to pull the schedule significantly to the left.  Looking at the numbers, it looks like we could have a return to the moon by 2021, if we had gone the depot route, instead of some time in the late 2020s/early-to-mid 2030s with SLS.

Missed opportunities.

~Jon
wow
would it be possible to get a copy of the study for L2?

I don't know about the underlying study, I was just talking about the public results. 

~Jon

Truly interesting.  If the shoe was on the other foot and an unsourced set of charts "buried deep within NASA" showed SLS to be cheaper, quicker, etc than prop depots and the largest of EELVs and a still-to-be-developed larger version of a rocket that has flown only twice, what would be the reaction around here?

Would it be called apples-to-apples?  Would these conclusions be accepted as gospel?  Would people want to know who put these *charts* together (or is more likely people would be calling conspiracies and somehow blaming Congress and supposedly pork-driven contractors?)?  Would a "friend" be allowed to be cited as a credible source suggesting that this is so good that somehow we can still move schedule to the left in pretty much any fiscal situation and STILL be under budget?  Would assumptions and bias still be allowed to be passed as fact?  And then after all that admit that nobody has seen the actual report/data set the *charts* are based on but just a set of briefing charts that "popped up". 

So again I ask the question shouldn't people, especially engineers or those who really care about the best and most economical solution, be calling for the release of all data?  Calling for the answers to certain other questions?  That ground-rules, assumptions, costing-models, etc  are equally applied?  That assumption and bias are eliminated from the evaluation process?  The list could go on.  I'm not afraid of those questions.

Again, I would also like to point out that prop depots and their existance/use are not the domain of only one group of launchers.  In fact, just because SLS may/will exist in some form or another does not preclude the use of other rockets either.

Of course, that all depends on the ultimate architecture, mission scopes, destinations, etc.  And of course nearly everyone around here doesn't want to answer those questions just instead prescribe a solution without those answers.

Finally, let's assume these charts are legit.  Let's assume someone in NASA starts asking questions.  Who do they go to without a source for who created these?  Does that not seem odd to anyone and why is that not being talked about?
Enjoying viewing the forum a little better now by filtering certain users.

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