Author Topic: ATK push for US space flight independence via Liberty  (Read 149893 times)

Offline Lobo

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Re: ATK push for US space flight independence via Liberty
« Reply #500 on: 02/12/2013 07:15 pm »
If ATK migrated the Liberty first stage concept over to their advanced composite expendable 4 segment solid - similar to their SLS proposal - suddenly their vehicle might start to promise some decent lifting power. The Ariane V based corestage is a good design and any Ariane V upgrades could reap benefits to Liberty II's performance.

But EPC and its Vulcain engine don't have a long term future.  Ariane 6 won't use them. ATK will have to use something else, which in my mind implies a different architecture. EPC was not a good match for the GTO mission anyway.

Ed Kyle

They might want to buy the tooling for those items.

Jim can probably answer this the best, but could ATK buy liquid upper stages from ULA, the same way they were playing to buy the Ariane 5 core from ArianeSpace?

The shorter, lower thrust EELV upper stage would mean Liberty would need a high thrust 2nd stage.  Fortunately, the Castor 120 upper stage that ATK already makes puts out roughly the same thrust as the Vulcan or J2X (more actually) , and would take care of that need, so a liquid upper stage would not need to be so high of thrust.  It has a burn time of 81 seconds.

But can ULA sell upper stages to ATK?  ULA buys EELV SRB's from ATK, so can that work the other way?

Offline Lobo

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Re: ATK push for US space flight independence via Liberty
« Reply #501 on: 02/12/2013 07:32 pm »
I've had a 'super-heavy' configuration preying on my mind for some time.  Basically, the bottom layer is a 2-1-2 parallel group of ACBs.  The outer pairs are ground lit and the central booster is air-lit.  The objective of the configuration is to get the DCSS with as much propellent as possible into LEO parking orbit.

Practical?

I wonder if thermal stress would be a problem for the center motor nozzle in this configuration.  Otherwise the 4x1 staging ratio would work, though 3x1 is more efficient for LEO.

 - Ed Kyle

What would the 4-seg composite booster as a first stage, Castor 120 as the 2nd stage, and DCSS as the 3rd stage do to LEO and GTO?

4-seg SLS composite booster may be overkill for the 1st stage, but it would be the same exact booster used for SLS for better commonality than a 3-seg variant or a new monolithic, etc.  SO I'm curious what performance that LV using a (hypothetically) existing full composite SLS booster, existing Castor 120 upper stage, and existing DCSS 3rd stage would do. 

A 3-seg, or 2-seg 1st stage booster could be later developed by ATK, to go with the Castor 120 2nd stage and DCSS 3rd stage for smaller payloads, as a cost cutting measure if they chose to do so. 
« Last Edit: 02/12/2013 07:41 pm by Lobo »

Online Robotbeat

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Re: ATK push for US space flight independence via Liberty
« Reply #502 on: 02/12/2013 08:26 pm »
Integration and logistics of such an enormous solid motor has got to be expensive. Maybe okay for NASA, but for everyone else spendy.
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 Lobo

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Re: ATK push for US space flight independence via Liberty
« Reply #503 on: 02/13/2013 12:35 am »
What would the 4-seg composite booster as a first stage, Castor 120 as the 2nd stage, and DCSS as the 3rd stage do to LEO and GTO?
I figure 14.5 tonnes LEO, 5.4 tonnes GTO, which is better than Atlas 5-401 but less capable than 411.  This rocket would gross 686 tonnes at liftoff and have a 2.2 thrust to weight ratio.

Now consider, for purposes of illustration, replacing that Castor 120 second stage with a single-segment RSRM, which is something that actually appears in the ATK catalog.  The second stage would weigh 183.5 tonnes, but only carry 152.5 tonnes of propellant, making it much less efficient than Castor 120.  This rocket would put 15.5 tonnes in LEO or 5.6 tonnes in GTO.  It would weigh 807 tonnes at liftoff.

The next step would be to replace that second stage with an identical weight composite case, HTPB propellant motor.  The rocket still weighs the same, but now it can lift 20 tonnes to LEO or 7.8 tonnes to GTO.  Atlas 431 territory now.

Finally, replace the first stage with a composite case equivalent.  The rocket liftoff weight falls to 767 tonnes, but payload rises to 22 tonnes LEO or 8.6 tonnes GTO.  Atlas 551 capability.

 - Ed Kyle

Interesting.  Be interesting to know what the final iteration there might run if ATK gets the SLS advanced booster.  Development if the 4-seg composite booster would be paid by NASA, so ATK would only need to pay for the development of a 1-seg 2nd stage, and  integrate it all with a liquid upper stage.  It would have to be less than Atlas-551 to compete.  I donít know if USAF/DoD would entertain much a new LV with the same pricetag and capabities of the Atlas variants already flying with their own pads on both coasts.  And as Atlas is already priced to high for most commercial business, such a Liberty LV wouldnít be able to compete costing as much as Atlas, and better than Atlas is now.
ButÖif this mostly solid LV were to have a total price tag that is at least somewhat lower than Atlas, then they could have an in to compete.  If itís significantly lower, then even better.  They might get deal with NASA to use KSC, as KSC seems to be the only pad talked about launching Liberty from, so everything already set up to stack the segments is already there.  And NASA wants to launch other LVís form KSC, so they may give them a good deal to do it.

If DCSS becomes the baseline iCPS and in-space state for NASA, then that would seem to be a logical choice for ATK to explore, as it would continue production where the Ariane 5 core might not.  Iíd think itíd be wise to steer away from the Ariane 5 core if it looks like ArianeSpace will be moving to Ariane 6.  Maybe ATK could buy up a whole bunch of cores before they shut down production and store them?   

I wonder if there are any other liquid upper stages available besides DCSS that ATK could buy?  Even if ULA will sell them to ATK, theyíll probably still be pretty spendy, as Iím sure they are a big chunk of the cost of a Delta IV Medium+ LV. 
And the Ariane core would really be too tall and powerful when used with the 1-seg composite upper stage.  That much thrust isnít needed them.  Almost needs something in between like WBC or ACES. 

Offline Lobo

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Re: ATK push for US space flight independence via Liberty
« Reply #504 on: 02/13/2013 12:41 am »

Finally, replace the first stage with a composite case equivalent.  The rocket liftoff weight falls to 767 tonnes, but payload rises to 22 tonnes LEO or 8.6 tonnes GTO.  Atlas 551 capability.

 - Ed Kyle

Ed,
What would the performance be, if Liberty II was just Liberty, with the 4-seg SLS composite advanced booster, and the original Araine 5 core?

And would would a castor 30XL 3rd stage (that ATK will already be making for OSC) do for the GTO capacity of it vs. without? (Or could a Castor 30XL be used for a 3rd stage even?)

« Last Edit: 02/13/2013 12:43 am by Lobo »

Offline Lobo

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Re: ATK push for US space flight independence via Liberty
« Reply #505 on: 02/14/2013 05:42 am »
Ed,
What would the performance be, if Liberty II was just Liberty, with the 4-seg SLS composite advanced booster, and the original Araine 5 core?

And would would a castor 30XL 3rd stage (that ATK will already be making for OSC) do for the GTO capacity of it vs. without? (Or could a Castor 30XL be used for a 3rd stage even?)
This gets to really be guess-work, since all of the U.S. numbers are hidden behind ITAR walls - even for SLS as has been reported.  So the answers have to be taken as guesstimates with their implied big error bars.

ATK originally reported Liberty able to lift 20 tonnes to LEO or 8.845 tonnes to GTO.  The GTO number implied use of an ESC-A like stage powered by a restartable Vinci-like engine. 

If we guess that five-segment booster is replaced by a composite case motor with a 0.89 propellant mass fraction (like SRMU) and a few ticks higher specific impulse (I'll guess 270 seconds vacuum, 260 seconds average for the burn, but the real number could be higher), LEO payload goes to 22 tonnes and GTO rises to 10 tonnes.

Using Castor 30B in place of the ESC type stage would give 7.5 tonnes to GTO for five-segment booster and 8.4 tonnes to GTO for my guesstimated advanced booster (surprisingly good results), but these numbers will very much depend on tweaking the mission to have the second stage also reach a near parking orbit and for the third stage to coast to the first equator crossing for its burn.

 - Ed Kyle
Thanks Ed.  I appreciate the info.

Sounds like the ECS type stage would be more efficient than a Castor 30, which makes sense as it's hydrolox.  Castor 30 would have the advantage of being owned by ATK, one less thing for them to purchase, and it would be shared by Antares. 
But, if they are alreayd buying Ariane 5 cores from ArianeSpace, they could maybe buy ESC-A or ESC-B as part of the deal for missions that need them.  And that stage, like the core stage, would be shared with Ariane 5...for the time being anyway.

Would you think ATK would be at benefit to go along with their original plan of buying ESC-A from ArianeSpace, or their own Castor 30?

and by "ESC-A" like, I assume you mean buying ESC-A directly from ArianeSpace?  or some other existing similar upper stage if there were one available for a cheaper price?

I'm not all that read up on Ariane 5 hardware so just learning about it's upper stage now.

Ok, so to round out my complete pestering you for information, what would the performance be of Liberty with the advanced composite booster, standard Ariane 5 core/upper stage, and an ESC-A 3rd stage?...if ATK entertained sticking with that rather than (in my concept) going with a solid 3rd stage that they make themselves like Castor 30's...

If Original Liberty was to be about 8.8mt to LEO that way, then I would guess from your numbers above, it would be around 9.8mt to LEO?

That would pretty much duplcate Ariane 5.  On the flip side, it would probably be as expensive as Ariane 5 too.  One big solid booster rather than two smaller ones for Ariane.  Ariane 5's core and upper stage. 

So...hmmm....still sorta hard to see how they have an LV that will be any kind of cost or performance advantage over FH or Atlas-551 or Ariane 5.  Seems more like ATk would just make a serial staged Ariane 5, which is struggling with some cost issues of it's own as I understand (hence Ariane 6).  Maybe if ATK's new composite boster will be really cheap...dunno...

Maybe if ATK were to develop the 1-seg composite upperstage booster in addition to the SLS 4-seg composite booster.  and then buy an ECA-B upper stage on top of that like we looked at with DCSS, ECA-B (Vinci engien) seems to be very close to DCSS size, but perhaps could be a lower price?  And it sounds like it would be the upper stage for Ariane 6 so it would remain in produciton either way.
So that would decouple Liberty from the Ariane 5 core in case it goes away, and ties it to the new upper stage that will be used on Ariane 5 and later on Ariane 6.  And that puts the solid upper stage handling the lower altidude duties where it's low isp isn't such a drawback, but it's high thrust is an adavntage.  Then hydrolox for the 3rd stage.
Just a thought.

Offline Patchouli

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Re: ATK push for US space flight independence via Liberty
« Reply #506 on: 02/15/2013 03:32 am »
Ed,
What would the performance be, if Liberty II was just Liberty, with the 4-seg SLS composite advanced booster, and the original Araine 5 core?

And would would a castor 30XL 3rd stage (that ATK will already be making for OSC) do for the GTO capacity of it vs. without? (Or could a Castor 30XL be used for a 3rd stage even?)
This gets to really be guess-work, since all of the U.S. numbers are hidden behind ITAR walls - even for SLS as has been reported.  So the answers have to be taken as guesstimates with their implied big error bars.

ATK originally reported Liberty able to lift 20 tonnes to LEO or 8.845 tonnes to GTO.  The GTO number implied use of an ESC-A like stage powered by a restartable Vinci-like engine. 

If we guess that five-segment booster is replaced by a composite case motor with a 0.89 propellant mass fraction (like SRMU) and a few ticks higher specific impulse (I'll guess 270 seconds vacuum, 260 seconds average for the burn, but the real number could be higher), LEO payload goes to 22 tonnes and GTO rises to 10 tonnes.

Using Castor 30B in place of the ESC type stage would give 7.5 tonnes to GTO for five-segment booster and 8.4 tonnes to GTO for my guesstimated advanced booster (surprisingly good results), but these numbers will very much depend on tweaking the mission to have the second stage also reach a near parking orbit and for the third stage to coast to the first equator crossing for its burn.

 - Ed Kyle

Why not consider using the Delta-K or similar as the third stage since a variant of AJ-10 should remain in production for Orion?
« Last Edit: 02/15/2013 03:36 am by Patchouli »

Offline Zed_Noir

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Re: ATK push for US space flight independence via Liberty
« Reply #507 on: 02/17/2013 02:55 am »
Why not consider using the Delta-K or similar as the third stage since a variant of AJ-10 should remain in production for Orion?
It would have to be bigger than the Delta second stage, which only grosses a bit less than 7 tonnes (compared to 19 tonnes for ESC-A, 14 tonnes for Castor 30, etc.).  Transtage, which used two AJ-10 engines, weighed about 12.5 tonnes at liftoff, so something about that size starts to be feasible.  Note that Titan 3C and 34D - rockets just below Liberty class capability - used that very stage for GTO-GEO missions.  (There are still numerous Transtages out there in orbit, but the last one lifted off in 1989.)

 - Ed Kyle

It occurs to me if SpaceX will sell SuperDraco engines. A  SuperDraco is roughly the same performance as the 2 AJ-10 on the Transtage. Also you don't have to deal with Aerozine 50 as a propellant.

Offline guckyfan

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Re: ATK push for US space flight independence via Liberty
« Reply #508 on: 02/17/2013 07:44 am »

SuperDraco's nominal burn time is only five seconds.  It would have to burn for several minutes at a time if used for primary propulsion.

 - Ed Kyle

Interesting point. I have suggested a discussion on the General Falcon and Dragon discussion thread.

http://forum.nasaspaceflight.com/index.php?topic=30385.msg1013983#msg1013983

Offline Chris Bergin

Re: ATK push for US space flight independence via Liberty
« Reply #509 on: 02/18/2013 08:17 pm »
I've moved the four posts that ignored the above and continued to be very off topic on this thread into the above link.

People really have to learn about not going off topic. *Bangs head against a brick wall*.

Offline pberrett

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Re: ATK push for US space flight independence via Liberty
« Reply #510 on: 07/12/2013 08:53 am »

Isn't there a fundamental design problem with the solid rocket booster?

I remember seeing some discussion with Ares about whether an abort system would be able to get itself far away enough in the event of a booster explosion. Wouldn't the same apply here?

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