Author Topic: SLS using ULA's ACES Lunar Architecture Proposal  (Read 4667 times)

Offline Lobo

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SLS using ULA's ACES Lunar Architecture Proposal
« on: 10/07/2011 10:16 PM »
This came up on the SLS/SSME thread, but as it's kind of off topic, I decided to make a separate thread about it.

So, here's the proposals that are giving birth to this.

The earlier proposal
http://www.ulalaunch.com/site/docs/publications/LunarLanderConfigurationsIncorporatingAccessibility20067284.pdf

Then refined with ACES.
http://www.ulalaunch.com/site/docs/publications/AffordableExplorationArchitecture2009.pdf

Now, this architecture is sized and optimized for an all EELV architecture that would necessitate both a LEO propellent depot, and a lunar orbit propellent depot.  Basically, the EELV would lift the components dry, they'd dock at the LEO propellent depot and refuel, then do their own TLI burns to the Lunar depot (which they have at L2, but could also be in some type of lunar orbit, or maybe L1.), the Orion is parked there with it's cryo residuals pumped into the depot for more efficient cold storage.  The same for the lander.  The crew transfers to the lander, and the lander is pumped full, both the ACES descent stage, and the ascender tanks.  (everything is completely cryo, even the RCS systems using GH2 boiloff)  The crew descends, does it's mission, and the ascender returns to the lunar depot.  It parks the ascender there for storage and future use, and the crew transfers back to Orion/ACES.  enough fuel is pumped back into Orion/ACES for TEI burn.  and the crew returns to Earth.

I -really- like this concept for a few reasons.
1)  It shares many systems and technologies and manufacturing with the common upper stage ULA wants to develop anyway for D4 and A5.  So it's not a 1-off ship.
2)  The lunar depot gives Orion a place to park during the mission so the whole crew can go to the suface.
3)  The lunar ascender can park at the lunar depot between missions for reuse. 
4)  The depots share many systems and technologies with ACES/ORion SM/lunar descent stage.  All are based on the same platform for maximum commonality.
5)  The architecture is 100% hydrolox.  No nasty hypergolics.  Hydrolox is the most efficient fuel, and refueling the main propulsion would also refuel the RCS system.  Residuals could be used by the crew for breathing air, water, and to drive fuel cells.  A big hurdle to having any type of reusable lander, is not only refueling it's main propulsion, but refueling it's hypergolic RCS system.  This system eliminates that.
LH2 and LO2 can be pumped around as needed.  from and to each ship, and from and to the depot.  Contingency fuel can be sent up ahead of time via an ACES tanker. 
6)  The lander is horizontal, eliminating the issue of having a very tall lander.  The tanking system is far more simple and mass efficient because (other than the smaller tanks on the ascender) everything is a single common bulkhead tank instead of a bank of smaller tanks like CxP Altair had. 
7)  This system -should- be much more affordable than a purpose build 1-off system. 

There are a couple of cons however.

1)  An ACES Service module for Orion would work for this sytem, but wouldn't probably work very well for a long duration trip to a NEO or Venus flyby.  So a 2nd service module, more like what's currently the likely PoR would be developed anyway.

2)  This system is optimized for EELV's with two depots, not for SLS.  So there may be some inefficiencies in integration of the two systems.  For example, this system is designed so that the Orion SM and lander DM will do the earth departure burn, rather than a separate earth departure stage.  And it sounds like SLS will have it's own purpose built EDS one way or the other.  So that's one issue.

This thread is mainly about #2 here.  The issues with integrating the two systems. 

What are the pros, cons, etc. of doing that.  Is it feasible vs. a purpose built lander designed specifically for maximum utilization of SLS. 
(Obviously this assumes some type of lunar landing architecture is greenlighted at some point in the future.  :-)  )

SLS Block 2 won't be able to push two fuelly fueled ACES-41's with ORion and Ascender through TLI.   I haven't really seen any numbers on on what SLS will be able to put through TLI.  But the Saturn V, per Wikipedia (for whatever that is worth) said the LEO capacity was 119mt, with 45mt through TLI (which was the mass of the Apollo CSM + LEM).  So 1mt of TLI for every 2.64mt to LEO.  So if that ratio is true for SLS, that's just shy of 50mt to TLI.  (let me know if that's anywhere near ballpark for SLS).

So if Orion is 9mt (capsule, crew, equipment, and ECLSS...ULA's numbers), and a fueled DTAL ascender is about 7mt, and your two ACES stages are about 5mt each (less probably since they'd probably only have one RL-10 each since they won't be doing the TLI burn like they would have been with EELV's)  So, we're talking about 12mt of fuel for each module. 

And that's probably ok.  the LEM DM was about 10mt and that landed over 5mt on the surface.  The LEM DM was about 2mt dry, and 8mt of hypergolic propellant.  The ACES DM would be about 4-5mt dry, with about 10-12mt of propellent.

But now we're getting into the tall weeds that are over my head.  So I'm curious what the big brains think about how this might all work.

Anyway idea is, how feasible is it to stack ORion/ACES and DTAL/ACES on top of an SLS-Block 2 and run a single-launch lunar mission?  Once there was a lunar depot up, then you could put extra fuel in the DTAL/ACES lander, so you could land larger masses than you would otherwise with a single launch only. 
Maybe they'd need to build a shortened ACES stage as the ORion SM and DTAL DM if you can't launch them partially fueled?  I don't know if that's a problem or not.  BEtter if you can stick with the ACES-41 for commonality.

Offline Lobo

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #1 on: 10/10/2011 11:16 PM »
300 views but no input?  Did I propose that big of a dud of a topic??

;-)

Offline Proponent

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #2 on: 10/11/2011 01:47 AM »
Well, it seems to me that this is the ULA paper of greatest current interest, though we should probably be discussing these things elsewhere than the HLV/SLS sub-forum.

EDIT:  Inserted missing "though."
« Last Edit: 10/11/2011 06:59 AM by Proponent »

Offline Warren Platts

Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #3 on: 10/11/2011 06:42 AM »
300 views but no input?  Did I propose that big of a dud of a topic??

;-)

Nah, it just makes too much sense....
"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

Offline blasphemer

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #4 on: 10/11/2011 06:50 AM »
Yep, makes too much sense. Until decision-makers realise this, we will be stuck with expensive oversized launchers and throwaway architectures, sadly.

Offline Patchouli

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #5 on: 10/11/2011 07:20 AM »
I always thought ULAs DTAL lander was the most logical path for a large lander.
It certainly made a lot more sense then Artair's design.
« Last Edit: 10/11/2011 07:21 AM by Patchouli »

Offline Ben the Space Brit

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #6 on: 10/11/2011 08:25 AM »
I think that the ULA lumar and Martian archetectures are doomed for the 'great idea but...' file.  There is no doubt that great things could have been done with it.  Unfortunately, it met few if any of the hidden political goals of NASA's HSF program.

Equally unfortunately, it could not be easily started using STS and CxP contracts as starting points.  Using this concept would have likely led to years of contracting and legal delays that make the current SLS booster re-bid squabble look like a picnic.

Like Apollo Applications, it will be left to generations of space enthusiasts to sigh and say "if only..." :(
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Offline Lobo

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #7 on: 10/11/2011 08:03 PM »
Yep, makes too much sense. Until decision-makers realise this, we will be stuck with expensive oversized launchers and throwaway architectures, sadly.

Well, the point being, how to use ULA's ACES proposal with this expensive, oversized launcher that is the PoR now.  ;-)
Not going back to an all EELV plan as ULA's plan entailes.

Offline BrightLight

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Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #8 on: 10/11/2011 08:49 PM »
What a difference a day makes!
I get the feeling Lobo that the DTAL proposal would "look" better if it were just a little bigger - sometimes engineering insufficiency is mitigated by political need.  The 2009 proposal looked very good technically but not politically.  To offset this, two SLS launches with a lunar orbit depot for fuel, Orion and long-term infrastructure and a second LV with 2 DTALs with surface logistics: one manned the other cargo (Waving my hands at the white board furiously  ;) )

Offline RocketmanUS

Re: SLS using ULA's ACES Lunar Architecture Proposal
« Reply #9 on: 01/24/2012 03:36 AM »
Fully reusable DTAL at L1/2 fuel depot.

Launch SLS block II with ACES/Orion with fuel for DTAL and depot.

Could a larger than ACES 41 such as ACES 71 be used for an ACES/Orion for the extra fuel needed for the DTAL and fuel depot ( station keeping )?
Mars and beyond, human exploration
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