Author Topic: Starship/Booster Propellant Questions  (Read 7977 times)

Offline Swamp1983

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Starship/Booster Propellant Questions
« on: 10/22/2023 11:09 pm »
So, been wondering how often the propellant for the starship and booster can be recycled through tanks? And is there a “shelf life” for it sitting in those tanks?

Re: Starship/Booster Propellant Questions
« Reply #1 on: 10/22/2023 11:35 pm »
Both liquid methane and liquid oxygen are pretty inert by themselves, so it would be reasonable to assume indefinite shelf life, as long as they stay cold and liquid.
There may potentially be some contamination from the seals and valves involved in the pumping process, but that should be minimal given the volumes of fluid involved. The effect, if any, would most likely only show up during the combustion process, as there is no good way to get a response from the propellants by themselves.

Offline Swamp1983

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Re: Starship/Booster Propellant Questions
« Reply #2 on: 10/23/2023 01:23 am »
Huh, thanks. Just wondering. Thanks

Offline spacenut

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Re: Starship/Booster Propellant Questions
« Reply #3 on: 10/23/2023 01:58 am »
Liquid natural gas (95%+/- methane) is liquified in summer and used in winter.  This means it can be stored as liquid for 6 months or more.  It is stored in very large tanks that are double hulled with a vacuum pulled between the hulls to make the storage tanks like a thermos bottle. 
« Last Edit: 10/23/2023 02:22 am by spacenut »

Offline Michael S

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Re: Starship/Booster Propellant Questions
« Reply #4 on: 10/23/2023 02:19 am »
The question that occurs to me is: How much propellant is lost with every tanking test?
And in parallel, how much Nitrogen is lost with each tanking cycle? (Since we know that Nitrogen is used for both chilling before tanking and in de-tanking in the recondensers)
Also, how do Nitrogen losses compare to Oxygen and Methane when substituted for propellant?

Offline DanClemmensen

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Re: Starship/Booster Propellant Questions
« Reply #5 on: 10/23/2023 02:41 am »
The question that occurs to me is: How much propellant is lost with every tanking test?
And in parallel, how much Nitrogen is lost with each tanking cycle? (Since we know that Nitrogen is used for both chilling before tanking and in de-tanking in the recondensers)
Also, how do Nitrogen losses compare to Oxygen and Methane when substituted for propellant?
There is no practical way to recover any of the Nitrogen. The gasses are all trucked in. The liquid Nitrogen is basically a storage system that stores "cold". That "cold" is used to recover the methane by recondensing it, and boiled Nitrogen converts to a gas which is vented. It would in theory be possible to recondense the Oxygen by boiling more Nitrogen, but that is probably uneconomical.

At some point, SpaceX will need a co-located gas liquifaction plant it keep pace with a high launch cadence. These plants use lots of electricity instead of lots of trucks. At that point the economics might change in theory. I don't know in practice

Offline deltaV

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Re: Starship/Booster Propellant Questions
« Reply #6 on: 10/23/2023 04:20 am »
At some point, SpaceX will need a co-located gas liquifaction plant it keep pace with a high launch cadence. These plants use lots of electricity instead of lots of trucks. At that point the economics might change in theory. I don't know in practice

IIRC some of SpaceX's early star base plans included a liquefaction plant and a power plant to power it. My guess is they may have dropped those plans when they realized it would make the red tape (e.g. environmental review) harder.

Offline Nomadd

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Re: Starship/Booster Propellant Questions
« Reply #7 on: 10/23/2023 06:14 am »
At some point, SpaceX will need a co-located gas liquifaction plant it keep pace with a high launch cadence. These plants use lots of electricity instead of lots of trucks. At that point the economics might change in theory. I don't know in practice

IIRC some of SpaceX's early star base plans included a liquefaction plant and a power plant to power it. My guess is they may have dropped those plans when they realized it would make the red tape (e.g. environmental review) harder.
The plant has been built for years. You can hear the compressors running sometimes. I figured they were waiting for the new power lines to light up, but I haven't haven't been there in a while.
« Last Edit: 10/23/2023 12:37 pm by Nomadd »
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Offline DanClemmensen

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Re: Starship/Booster Propellant Questions
« Reply #8 on: 10/23/2023 12:49 pm »
At some point, SpaceX will need a co-located gas liquifaction plant it keep pace with a high launch cadence. These plants use lots of electricity instead of lots of trucks. At that point the economics might change in theory. I don't know in practice

IIRC some of SpaceX's early star base plans included a liquefaction plant and a power plant to power it. My guess is they may have dropped those plans when they realized it would make the red tape (e.g. environmental review) harder.
The plant has been built for years. You can hear the compressors running sometimes. I figured they were waiting for the new power lines to light up, but I haven't haven't been there in a while.
Is/was that plant intended for Oxygen and Nitrogen, or to purify and liquefy methane, or both?

Offline Nomadd

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Re: Starship/Booster Propellant Questions
« Reply #9 on: 10/23/2023 07:25 pm »
At some point, SpaceX will need a co-located gas liquifaction plant it keep pace with a high launch cadence. These plants use lots of electricity instead of lots of trucks. At that point the economics might change in theory. I don't know in practice

IIRC some of SpaceX's early star base plans included a liquefaction plant and a power plant to power it. My guess is they may have dropped those plans when they realized it would make the red tape (e.g. environmental review) harder.
The plant has been built for years. You can hear the compressors running sometimes. I figured they were waiting for the new power lines to light up, but I haven't haven't been there in a while.
Is/was that plant intended for Oxygen and Nitrogen, or to purify and liquefy methane, or both?
They called it an air plant, so I assumed it was for O2, N2 and Argon.
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline alugobi

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Re: Starship/Booster Propellant Questions
« Reply #10 on: 10/23/2023 07:27 pm »
RGV vids show that it's being dismantled.

Offline Barley

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Re: Starship/Booster Propellant Questions
« Reply #11 on: 10/26/2023 09:24 pm »

 The plant has been built for years. You can hear the compressors running sometimes. I figured they were waiting for the new power lines to light up, but I haven't haven't been there in a while.
What size plant are you talking about?  Shipping container sized units to produce industrial gases are common in moderate sized factories.  They might have one of those to support the welding operations, rather than rocket launches.

Offline sanman

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Re: Starship/Booster Propellant Questions
« Reply #12 on: 11/20/2023 11:39 pm »
So is a liquid-fueled booster worth it? What if SH had been a giant SRB instead?

Look at all the potential problems with fuel-sloshing, ullage, fluid hammer, etc. Wouldn't a giant SRB have avoided all this?

While recognizing the desire for rapid turnaround in booster re-use, couldn't that be solved through the right SRB manufacturing supply chain approach? Like what occurs with the rapid production of SS & SH from their production line, only more so.

It just seems like the bigger you get, the more problems the fluids can pose - ie. the more slosh, the more ullage, the more fluid hammer, etc, etc.

Do fluids really scale well?
Don't their complications then make for a very tight operating envelope that increases chances for failure?


Offline matthewkantar

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Re: Starship/Booster Propellant Questions
« Reply #13 on: 11/20/2023 11:54 pm »
So is a liquid-fueled booster worth it? What if SH had been a giant SRB instead?

Look at all the potential problems with fuel-sloshing, ullage, fluid hammer, etc. Wouldn't a giant SRB have avoided all this?

While recognizing the desire for rapid turnaround in booster re-use, couldn't that be solved through the right SRB manufacturing supply chain approach? Like what occurs with the rapid production of SS & SH from their production line, only more so.

It just seems like the bigger you get, the more problems the fluids can pose - ie. the more slosh, the more ullage, the more fluid hammer, etc, etc.

Do fluids really scale well?
Don't their complications then make for a very tight operating envelope that increases chances for failure?
Liquid props scale waaaaay better than solids.
-Solids get more difficult to build the bigger they get.
-Solids have abysmal ISP, which is not bad for a first stage, but a big problem for upper stages.
-How are you going to land a giant solid rocket? NASA stopped parachute/splashdown recovery of solids because it’s cheaper to build new ones.
-edit to add: how are you going to refuel solids in orbit to open up the solar system?
« Last Edit: 11/20/2023 11:55 pm by matthewkantar »

Offline sanman

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Re: Starship/Booster Propellant Questions
« Reply #14 on: 11/21/2023 12:18 am »
Liquid props scale waaaaay better than solids.
-Solids get more difficult to build the bigger they get.


Okay, so that's a manufacturing problem, not an operating problem. Manufacturing problems too can likewise be solved through R&D engineering effort.


Quote
-Solids have abysmal ISP, which is not bad for a first stage, but a big problem for upper stages.


And I'm specifically talking about the SuperHeavy booster here, not the Starship itself.
I understand that would make for a more heterogenous system in some ways, but in other ways it could simplify things.


Quote
-How are you going to land a giant solid rocket? NASA stopped parachute/splashdown recovery of solids because it’s cheaper to build new ones.


Well, Space Shuttle SRBs were famously recoverable and reusable. Sure, SH is much bigger, but parachutes can be made bigger too. Maybe the simplicity of such a big dumb booster and cost amortization across its re-usable life would justify manufacturing it out of composites.


Quote
-edit to add: how are you going to refuel solids in orbit to open up the solar system?

Starship upper stage would still be liquid-fueled. I'm talking about SuperHeavy specifically.


Look - if you're going to re-use the booster enough times and at a high enough cadence, then you're running an increasing risk that some flight or other will see cracks or other flaws appear in the booster vehicle due to flight stresses. And then the next launch will be the catastrophic event that destroys Stage Zero and whatever surrounds it. How are you going to have adequate safety inspection of such a complex system in a high-cadence operation, which becomes especially important with more re-uses/re-flights?

The rock tornado from IFT-1 seemed bad enough. I can't even imagine how devastating the explosion of the fully-fueled launch stack on the pad would be. Probably like a mini-nuke.
« Last Edit: 11/21/2023 12:25 am by sanman »

Offline MichaelBlackbourn

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Re: Starship/Booster Propellant Questions
« Reply #15 on: 11/21/2023 01:02 am »
Mini nuke! Now let’s fuse the atoms to iron! Watch out planet earth.

Offline Jim

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Re: Starship/Booster Propellant Questions
« Reply #16 on: 11/21/2023 01:55 am »
Liquid props scale waaaaay better than solids.
-Solids get more difficult to build the bigger they get.


Okay, so that's a manufacturing problem, not an operating problem. Manufacturing problems too can likewise be solved through R&D engineering effort.


Quote
-Solids have abysmal ISP, which is not bad for a first stage, but a big problem for upper stages.


And I'm specifically talking about the SuperHeavy booster here, not the Starship itself.
I understand that would make for a more heterogenous system in some ways, but in other ways it could simplify things.


Quote
-How are you going to land a giant solid rocket? NASA stopped parachute/splashdown recovery of solids because it’s cheaper to build new ones.


Well, Space Shuttle SRBs were famously recoverable and reusable. Sure, SH is much bigger, but parachutes can be made bigger too. Maybe the simplicity of such a big dumb booster and cost amortization across its re-usable life would justify manufacturing it out of composites.


Quote
-edit to add: how are you going to refuel solids in orbit to open up the solar system?

Starship upper stage would still be liquid-fueled. I'm talking about SuperHeavy specifically.


Look - if you're going to re-use the booster enough times and at a high enough cadence, then you're running an increasing risk that some flight or other will see cracks or other flaws appear in the booster vehicle due to flight stresses. And then the next launch will be the catastrophic event that destroys Stage Zero and whatever surrounds it. How are you going to have adequate safety inspection of such a complex system in a high-cadence operation, which becomes especially important with more re-uses/re-flights?

The rock tornado from IFT-1 seemed bad enough. I can't even imagine how devastating the explosion of the fully-fueled launch stack on the pad would be. Probably like a mini-nuke.

Solid would be worse.

They don't doesn't scale.   Too big and would take 1000 ton cranes or more.  Exhaust is more toxic and erosive.   
Explosion would be worse with burning chunks everywhere.
Can't land. Too big for parachutes.
Costly to reuse.

Actually, solid is not feasible. 

Offline Brigantine

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Re: Starship/Booster Propellant Questions
« Reply #17 on: 11/21/2023 02:41 am »
would take 1000 ton cranes or more
Lets work out a number for that...

if stage 2 is 1200t methalox + 120t dry + 0t payload = 1320t
assume for now stage 1 without fuel is still 200t
best-case ISP seems to be 304s (I'm surprised, I thought it would be far lower than that)
ignore gravity drag for now and just accelerate the stack to 1800 m/s
I get 1260t of solid fuel, so 1460t on the gantry cranes, SPMTs and chopsticks.

What impact would it have on exclusion zones? I often hear how SH is not "a nuke" because the meth and lox are not well mixed

Offline sanman

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Re: Starship/Booster Propellant Questions
« Reply #18 on: 11/21/2023 04:14 am »
Methane's freezing point is -182 C (exactly the same as LOX temperature, and well above LH2 temperature) so is there any chance of using solid methane as a fuel? You'd then heat/melt portions of it to flow it into the engines. This might require that the fuel tank be compartmentalized into smaller cells/slices, each of which could be heated/thawed as required. This would limit the amount of slosh, fluid hammer, avoid ullage effects, etc.

LOX freezing point is -219 C, which is still above LH2 temperatures.
« Last Edit: 11/21/2023 04:17 am by sanman »

Online meekGee

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Re: Starship/Booster Propellant Questions
« Reply #19 on: 11/21/2023 05:37 am »
would take 1000 ton cranes or more
Lets work out a number for that...

if stage 2 is 1200t methalox + 120t dry + 0t payload = 1320t
assume for now stage 1 without fuel is still 200t
best-case ISP seems to be 304s (I'm surprised, I thought it would be far lower than that)
ignore gravity drag for now and just accelerate the stack to 1800 m/s
I get 1260t of solid fuel, so 1460t on the gantry cranes, SPMTs and chopsticks.

What impact would it have on exclusion zones? I often hear how SH is not "a nuke" because the meth and lox are not well mixed
I think empty weight will be much higher since the entire thing is a combustion chamber (of 9 m diameter!)
ABCD - Always Be Counting Down

Online meekGee

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Re: Starship/Booster Propellant Questions
« Reply #20 on: 11/21/2023 05:37 am »
Senior Sanman you are going the wrong way!
ABCD - Always Be Counting Down

Offline matthewkantar

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Re: Starship/Booster Propellant Questions
« Reply #21 on: 11/21/2023 01:59 pm »
Where is the member with the tag line about solid rockets being a branch of fireworks?
« Last Edit: 11/21/2023 03:06 pm by matthewkantar »

Offline Jim

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Re: Starship/Booster Propellant Questions
« Reply #22 on: 11/21/2023 03:07 pm »
Methane's freezing point is -182 C (exactly the same as LOX temperature, and well above LH2 temperature) so is there any chance of using solid methane as a fuel? You'd then heat/melt portions of it to flow it into the engines. This might require that the fuel tank be compartmentalized into smaller cells/slices, each of which could be heated/thawed as required. This would limit the amount of slosh, fluid hammer, avoid ullage effects, etc.

LOX freezing point is -219 C, which is still above LH2 temperatures.
No, too complex.    Slosh is not a problem.  If it is, there are easy fixes.

Offline JamesH65

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Re: Starship/Booster Propellant Questions
« Reply #23 on: 11/21/2023 03:13 pm »
You cannot turn a solid off or throttle it. Just that would make it a non-worker.

Offline sanman

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Re: Starship/Booster Propellant Questions
« Reply #24 on: 11/21/2023 03:18 pm »
Senior Sanman you are going the wrong way!

I'm not going - I'm simply asking  :)

Offline Slarty1080

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Re: Starship/Booster Propellant Questions
« Reply #25 on: 11/21/2023 04:08 pm »
would take 1000 ton cranes or more
Lets work out a number for that...

if stage 2 is 1200t methalox + 120t dry + 0t payload = 1320t
assume for now stage 1 without fuel is still 200t
best-case ISP seems to be 304s (I'm surprised, I thought it would be far lower than that)
ignore gravity drag for now and just accelerate the stack to 1800 m/s
I get 1260t of solid fuel, so 1460t on the gantry cranes, SPMTs and chopsticks.

What impact would it have on exclusion zones? I often hear how SH is not "a nuke" because the meth and lox are not well mixed
Superheavy holds around 2800 or more tonnes of propellants to do what it does, and solid propellants have a lower Isp than good liquid propellants so it seems unlikely that 1260 tonnes of solid propellant would be anywhere near enough. That should put an end to it.

But additionally parachutes don't scale well and immersion in salt water is not beneficial to say the least nor good for rapid reuse. Solid rockets also produce a lot more noxious gases when burnt and could present a contamination problems if there was any serious incident on the pad (eg ammonium perchlorate and wildlife don't mix). Check out an Ariane launch years ago that detonated a few miles up and scattered burning solid propellant chunks all of the place.

But beyond all that I can hear Mr Musk... and how much did you say these solid booster propellants cost compared to Methalox? Whilst his engineers shuffle uncomfortably in the background.
My optimistic hope is that it will become cool to really think about things... rather than just doing reactive bullsh*t based on no knowledge (Brian Cox)

Offline matthewkantar

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Re: Starship/Booster Propellant Questions
« Reply #26 on: 11/21/2023 10:10 pm »
From Wikipedia, on a big solid rocket projectl from the 1960’s:

“The largest solid rocket motors ever built were Aerojet's three 6.60-meter (260 in) monolithic solid motors cast in Florida. Motors 260 SL-1 and SL-2 were 6.63 meters (261 in) in diameter, 24.59 meters (80 ft 8 in) long, weighed 842,900 kilograms (1,858,300 lb), and had a maximum thrust of 16 MN (3,500,000 lbf).”
 
They had to dig a canal to move them. The final motor they tested is still in the hole they dug for it. The project was an uneconomic dead end.

Starship Booster will have around 90 MN of thrust at lift off, more than five times the 260, so a solid first stage would need to weigh ten million kg?

Offline Brigantine

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Re: Starship/Booster Propellant Questions
« Reply #27 on: 11/21/2023 10:30 pm »
ten million kg?
10 kilotons at Boca Chica

83m wide crater, 440m wide fireball, dry wood within 710m catches fire (dry wood in a wetland?), 5.8km high mushroom cloud, but the village survives
« Last Edit: 11/21/2023 10:37 pm by Brigantine »

Offline edzieba

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Re: Starship/Booster Propellant Questions
« Reply #28 on: 11/22/2023 10:41 am »
And the solid grains collapse under their own weight and fall out the nozzle to produce a very explosive but unhelpfully not propulsive pile of rubbery scraps.

No capes solids!

Offline Twark_Main

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Re: Starship/Booster Propellant Questions
« Reply #29 on: 11/22/2023 10:59 am »
So is a liquid-fueled booster worth it? What if SH had been a giant SRB instead?

...

Incoming tweet:

"Super Heavy is being redesigned again. Delightfully counterintuitive!!"
« Last Edit: 11/22/2023 11:00 am by Twark_Main »
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Offline launchwatcher

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Re: Starship/Booster Propellant Questions
« Reply #30 on: 11/22/2023 02:25 pm »
From Wikipedia, on a big solid rocket projectl from the 1960’s:

“The largest solid rocket motors ever built were Aerojet's three 6.60-meter (260 in) monolithic solid motors cast in Florida. Motors 260 SL-1 and SL-2 were 6.63 meters (261 in) in diameter, 24.59 meters (80 ft 8 in) long, weighed 842,900 kilograms (1,858,300 lb), and had a maximum thrust of 16 MN (3,500,000 lbf).”
 
They had to dig a canal to move them. The final motor they tested is still in the hole they dug for it. The project was an uneconomic dead end.

Starship Booster will have around 90 MN of thrust at lift off, more than five times the 260, so a solid first stage would need to weigh ten million kg?
There was a design study which looked at strapping four of those to a stretched Saturn V:

Quote
American orbital launch vehicle. Boeing study, 1967-1968. Use of full length 260 inch solid rocket boosters with stretched Saturn IC stages presented problems, since the top of the motors came about half way up the liquid oxygen tank of the stage, making transmission of loads from the motors to the core vehicle complex and adding a great deal of weight to the S-IC. Boeing's solution was to retain the standard length Saturn IC, with the 260 inch motors ending half way up the S-IC/S-II interstage, but to provide additional propellant for the S-IC by putting propellant tanks above the 260 inch boosters. These would be drained first and jettisoned with the boosters. This added to the plumbing complexity but solved the loads problem.
http://www.astronautix.com/s/saturnv4-260.html


Online Stan-1967

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Re: Starship/Booster Propellant Questions
« Reply #31 on: 11/22/2023 03:28 pm »

There was a design study which looked at strapping four of those to a stretched Saturn V:

Quote
American orbital launch vehicle. Boeing study, 1967-1968. Use of full length 260 inch solid rocket boosters with stretched Saturn IC stages presented problems, since the top of the motors came about half way up the liquid oxygen tank of the stage, making transmission of loads from the motors to the core vehicle complex and adding a great deal of weight to the S-IC. Boeing's solution was to retain the standard length Saturn IC, with the 260 inch motors ending half way up the S-IC/S-II interstage, but to provide additional propellant for the S-IC by putting propellant tanks above the 260 inch boosters. These would be drained first and jettisoned with the boosters. This added to the plumbing complexity but solved the loads problem.
http://www.astronautix.com/s/saturnv4-260.html

It is so hard to have a good new idea, and now I read that section from astronautix and realize how hard it is to have new bad ideas as well.

I was trying to think of a more bad idea than a +9m SRB to replace SH, then I had thoughts of encasing SH with off the shelf SLS style SRB's with +2cm thick steel casing ( pipe bombs) wrapped around the SH core.  That would take a stunning 1.6M to 2M lbs of steel casings falling back to earth. Turn SS/SH into a 2.5 stage beast like a Vulcan or A6 sustainer core configuration. 

I can think of only one company that would love this idea, &  I hope Mike Griffin never reads this thread.

And in my head I am singing Pink Floyd's "Two Suns in the Sunset"  thinking of the explosion that it would make.

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