Author Topic: Propellant depot strategy & tactics pow-wow  (Read 31639 times)

Offline StarGeezer

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Re: Propellant depot strategy & tactics pow-wow
« Reply #100 on: 08/27/2009 05:34 PM »
Hmmm... Shoulda posted in this thread...

So if everyone is so enamoured with analogies, how about extending the petrol/gas meme to outer space? It looks like space isn't going to happen anytime soon till big business gets aboard(sic). How about letting, say, the big oil companies/OPEC or some energy conglomerates have an exclusive to provide the first and only - for a while - gas'n'go fuel depot in LEO? If there's anything these guys can do - its the big single mega projects - transcontinental gas lines, deep shore wells, etc. A space depot would be a natural for them. Probably at a small fraction(sic) of their advertising budget - the goodwill generated would be better than anything they are doing now - sort of reverse the trend of being seen  as the 'bad' guys.

Offline adamsmith

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Re: Propellant depot strategy & tactics pow-wow
« Reply #101 on: 08/27/2009 07:52 PM »
Hmmm... Shoulda posted in this thread...

So if everyone is so enamoured with analogies, how about extending the petrol/gas meme to outer space? It looks like space isn't going to happen anytime soon till big business gets aboard(sic). How about letting, say, the big oil companies/OPEC or some energy conglomerates have an exclusive to provide the first and only - for a while - gas'n'go fuel depot in LEO? If there's anything these guys can do - its the big single mega projects - transcontinental gas lines, deep shore wells, etc. A space depot would be a natural for them. Probably at a small fraction(sic) of their advertising budget - the goodwill generated would be better than anything they are doing now - sort of reverse the trend of being seen  as the 'bad' guys.

I don't agree that the oil companies (or OPEC) have the technical ability to set up space propellant depots, but they do have the financial and management ability to handle very large engineering projects: the Alaska Pipeline.  In todays $, $30 BILLION in just 3 years, of their money, not the taxpayer's,  in some of the most inhospitable environments on Earth. Very cold, kinda like Mars.  These guys are real MEN with real guts.  To be honest, Bruce Willis types.  Gee, I wonder...

Stanley
« Last Edit: 08/27/2009 07:54 PM by adamsmith »

Offline StarGeezer

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Re: Propellant depot strategy & tactics pow-wow
« Reply #102 on: 08/27/2009 08:30 PM »
Quote
I don't agree that the oil companies (or OPEC) have the technical ability to set up space propellant depots, but they do have the financial and management ability to handle very large engineering projects: the Alaska Pipeline.  In todays $, $30 BILLION in just 3 years, of their money, not the taxpayer's,  in some of the most inhospitable environments on Earth. Very cold, kinda like Mars.  These guys are real MEN with real guts.  To be honest, Bruce Willis types.  Gee, I wonder...


So I doubt the oil company executives or decision makers can dig a hole for oil, weld a pipeline or operate a rig. But what they seem to be good at is organizing, paying for (arranging financing for - sorry) these mega-projects and gitin'r done. So imagine a converstation between Elox Muskoil of Exxoneration Corp and L-Bar Pickenavector of Conglomerated Space Agglomeration:

Elox: Howdy L-Bar I've been thinkin' about this new government contract they just put out for a space depot. I'm talking to our contractors to see if they can help out. Seems like we're gonna need some  heavy lifters to LEO for this thing. Can you help?

L-Bar: Sure can. Up to a hundred metric tons per rocket.

Elox: Probably need something a bit heavier. Ok L-Bar I'll get our people to talk to your people etc. etc. etc.


Offline Downix

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Re: Propellant depot strategy & tactics pow-wow
« Reply #103 on: 08/27/2009 08:56 PM »
Hmmm... Shoulda posted in this thread...

So if everyone is so enamoured with analogies, how about extending the petrol/gas meme to outer space? It looks like space isn't going to happen anytime soon till big business gets aboard(sic). How about letting, say, the big oil companies/OPEC or some energy conglomerates have an exclusive to provide the first and only - for a while - gas'n'go fuel depot in LEO? If there's anything these guys can do - its the big single mega projects - transcontinental gas lines, deep shore wells, etc. A space depot would be a natural for them. Probably at a small fraction(sic) of their advertising budget - the goodwill generated would be better than anything they are doing now - sort of reverse the trend of being seen  as the 'bad' guys.

I don't agree that the oil companies (or OPEC) have the technical ability to set up space propellant depots, but they do have the financial and management ability to handle very large engineering projects: the Alaska Pipeline.  In todays $, $30 BILLION in just 3 years, of their money, not the taxpayer's,  in some of the most inhospitable environments on Earth. Very cold, kinda like Mars.  These guys are real MEN with real guts.  To be honest, Bruce Willis types.  Gee, I wonder...

Stanley
Not quite true, while a large portion of the construction was done by private firms, the government was heavily involved in arranging the land rights necessary for the pipeline.  It took cooperation between the two, gov't and business, to get the pipeline done.
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Offline adamsmith

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Re: Propellant depot strategy & tactics pow-wow
« Reply #104 on: 08/27/2009 09:56 PM »
Hmmm... Shoulda posted in this thread...

So if everyone is so enamoured with analogies, how about extending the petrol/gas meme to outer space? It looks like space isn't going to happen anytime soon till big business gets aboard(sic). How about letting, say, the big oil companies/OPEC or some energy conglomerates have an exclusive to provide the first and only - for a while - gas'n'go fuel depot in LEO? If there's anything these guys can do - its the big single mega projects - transcontinental gas lines, deep shore wells, etc. A space depot would be a natural for them. Probably at a small fraction(sic) of their advertising budget - the goodwill generated would be better than anything they are doing now - sort of reverse the trend of being seen  as the 'bad' guys.

I don't agree that the oil companies (or OPEC) have the technical ability to set up space propellant depots, but they do have the financial and management ability to handle very large engineering projects: the Alaska Pipeline.  In todays $, $30 BILLION in just 3 years, of their money, not the taxpayer's,  in some of the most inhospitable environments on Earth. Very cold, kinda like Mars.  These guys are real MEN with real guts.  To be honest, Bruce Willis types.  Gee, I wonder...

Stanley
Not quite true, while a large portion of the construction was done by private firms, the government was heavily involved in arranging the land rights necessary for the pipeline.  It took cooperation between the two, gov't and business, to get the pipeline done.

What the Federal goverment gave them was immunity from the @#@#! environmentalists lawsuits that were seeking to block the pipeline.  They paid for everything.  Read Atlas Shrugged.  Fact is stranger than fiction.

Stanley

Offline alexterrell

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Re: Propellant depot strategy & tactics pow-wow
« Reply #105 on: 08/27/2009 10:16 PM »

http://www.lpi.usra.edu/publications/reports/CB-1106/wash01.pdf

Stanley
This uses the magsail. I first saw this described by Zubrin.

Has this (magasail for sailing around the solar system) been discussed in this forum and could someone provide a link?

Offline adamsmith

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Re: Propellant depot strategy & tactics pow-wow
« Reply #106 on: 08/27/2009 10:51 PM »

http://www.lpi.usra.edu/publications/reports/CB-1106/wash01.pdf

Stanley
This uses the magsail. I first saw this described by Zubrin.

Has this (magasail for sailing around the solar system) been discussed in this forum and could someone provide a link?

This does not use the Magsail, it uses a completely different mechanism.  the article provides references.

Offline Xplor

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Re: Propellant depot strategy & tactics pow-wow
« Reply #107 on: 08/28/2009 12:28 AM »
.
I am including the costs for the launches below.

Ross.

Is Ross trying to suggest that Direct can support 200mT/year for $959M ($4,796/Kg)?  Directs costs just to keep Michoud, ATK, PWR, KSC, MSFC, etc working will be >$2B not including any recurring launch costs.

I love the enthusiasm and thought of 8 or more annual missions, but over selling concepts will simply result in changing direction from the ESAS sales job to another fiasco in 4 years.
« Last Edit: 08/28/2009 12:29 AM by Xplor »

Offline jongoff

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Re: Propellant depot strategy & tactics pow-wow
« Reply #108 on: 08/28/2009 04:45 AM »
In the Direct 3.0 thread, Ross wrote:
With all the discussion recently, let me take a moment to try to clarify the Depot architecture decisions which we have made for DIRECT.

There is much debate about using an all-EELV-class approach.   What this would require, is approximately 9 launches for each mission.   Assuming a combination of 20mT and 25mT vehicles the following approach is hypothetically possible (though only if you choose to completely ignore the volume/diameter issues entirely):

1 Orion (fueled) -- Heavy
2 Lander Ascent Stage (fueled) -- Intermediate
3 Lander Descent Stage (dry) -- Heavy
4 EDS (mostly dry) -- Intermediate
5 Fuel for Descent Stage -- Intermediate
6 Fuel for EDS -- Intermediate
7 Fuel for EDS -- Intermediate
8 Fuel for EDS -- Intermediate
9 Fuel for EDS -- Intermediate

This architecture certainly requires the use of Propellant Transfer technologies and would almost-certainly require a full Depot to be deployed as part of the baseline Critical Path to success.

Of these 9 launches, the first 4 in that list are all mission critical and the loss of any one would result in an LOM situation.   The latter 5 launches are somewhat "interchangable" so there is "Partial Redundancy" possible there.   It's not too bad, but the logistics and the necessity to coordinate the launch of 4 of those vehicles perfectly in support of each mission, plus the constant fuel deliveries as well, makes it a very demanding logistical nightmare.

While this is definitely one way to do things, it's far from the optimum for a depot-centric architecture.  If you're going to do an LEO depot, making a second copy and sending it to L1/L2 makes a lot of sense (since it allows both of them to be small single-EELV-launch depots that don't require any on-orbit assembly).  With such a system, you don't need a lander descent stage anymore.  It is possible to refuel a Centaur-sized EDS in L1/L2, and have it do the Lx-to LUNO burn and a large chunk of the descent burn.  The lander DV is now quite a bit less than was needed for ESAS, and you can have it be a single-stage system, which tends to be more mass efficient for landers. 

The "Orion" can also be a lot smaller with such an architecture, because you don't need anywhere near as much delta-V to return to LEO, especially if you stage out of L2.

Sure, the logistics gets more involved, and I'll have to run the numbers on how many launches you need to do an ESAS-equivalent mission, but my point here was just to mention that a depot-centric architecture will not look like an HLV-centric architecture with depots tacked onto the side.  That's black-aluminum thinking.

~Jon

Offline sdsds

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Re: Propellant depot strategy & tactics pow-wow
« Reply #109 on: 08/28/2009 06:37 AM »
Thesis:  propellant depots will be successful to the extent that their advantages can be leveraged to market spaceflight products.

Exposition:
Imagine a future where NASA contracts with Lockheed-Martin for fully-fueled Earth-departure stages delivered on-orbit.  A good contract would specify penalties if LM could not provide a stage at the designated time, and bonuses if NASA requested a delivery delay (e.g. because the payload spacecraft would not be ready at the designated time).

Under contract terms like those, it might benefit LM to launch the stages early and operate a depot from which they could be replenished.  LM would choose to establish the depot because doing so would enable them to provide the product (fueled Earth-departure stages) with the high reliability and flexibility the customer wants.
-- sdsds --

Offline DonEsteban

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Re: Propellant depot strategy & tactics pow-wow
« Reply #110 on: 08/28/2009 01:46 PM »
While this is definitely one way to do things, it's far from the optimum for a depot-centric architecture.  If you're going to do an LEO depot, making a second copy and sending it to L1/L2 makes a lot of sense (since it allows both of them to be small single-EELV-launch depots that don't require any on-orbit assembly).  With such a system, you don't need a lander descent stage anymore.  It is possible to refuel a Centaur-sized EDS in L1/L2, and have it do the Lx-to LUNO burn and a large chunk of the descent burn.  The lander DV is now quite a bit less than was needed for ESAS, and you can have it be a single-stage system, which tends to be more mass efficient for landers. 

The "Orion" can also be a lot smaller with such an architecture, because you don't need anywhere near as much delta-V to return to LEO, especially if you stage out of L2.

Sure, the logistics gets more involved, and I'll have to run the numbers on how many launches you need to do an ESAS-equivalent mission, but my point here was just to mention that a depot-centric architecture will not look like an HLV-centric architecture with depots tacked onto the side.  That's black-aluminum thinking.

~Jon
OK, do I understand this correctly?

You launch crew vehicle (let's call it Orion) on top of 2-stage launcher to LEO depot. At the depot, the same second stage refuels and goes to an L2 depot (3.44km/s dv). There, the Orion is detached and reusable lander is attached to this second stage, which is also refueled.

The second stage then does the Moon descent burn (almost all of it, i.e. 2.52km/s dv, which is not too far off 3.44km/s dv, so it could sort of work) and then crashes (possibly taking care not to crash into existing moon infrastructure - or possibly crashing into designated 'scrap metal recovery area' - after all, its terminal velocity will be low, and it is a free source of processed 'stuff' on Moon), leaving the lander to do just the final landing.

Eventually, the lander flies off to L2, where the astronauts switch back to Orion and return to Earth.

Of course, there are additional fueling flight fueling the depots...

Offline jongoff

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Re: Propellant depot strategy & tactics pow-wow
« Reply #111 on: 08/28/2009 02:24 PM »
OK, do I understand this correctly?

That's pretty close.  My personal favorite nuance though is that if you top the Centaur back up all the way before doing the LX to LUNO burn, there's actually enough fuel leftover after staging for it to do a burn to return to LUNO and then to LX.  Reusing a stage that's only been used in-space, has not been contaminated by the lunar surface environment, and doesn't have to deal with the hellish reentry environment should be substantially easier.

Also you forgot to mention the step where you ship the actual lander out.  It would likely fly separately from the capsule, and depending on the dV split between the two, might even be capable of self ferrying.

Quote
Of course, there are additional fueling flight fueling the depots...

Quite a few.  But the hope is that these are run kind of like a logistics stream, instead of being ordered discretely, per mission.  The LX depot has fairly low boiloff, even passively cooled, so if you have a temporary dip in demand, you don't lose very much propellant from there.  So long as you treat the LEO depot as a "use it or lose it" waypoint that only exists to aggregate enough propellant for an outbound trip for L2, you can minimize your losses there too...

~Jon

Offline DonEsteban

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Re: Propellant depot strategy & tactics pow-wow
« Reply #112 on: 08/28/2009 02:59 PM »
OK, do I understand this correctly?

That's pretty close.  My personal favorite nuance though is that if you top the Centaur back up all the way before doing the LX to LUNO burn, there's actually enough fuel leftover after staging for it to do a burn to return to LUNO and then to LX.  Reusing a stage that's only been used in-space, has not been contaminated by the lunar surface environment, and doesn't have to deal with the hellish reentry environment should be substantially easier.

Also you forgot to mention the step where you ship the actual lander out.  It would likely fly separately from the capsule, and depending on the dV split between the two, might even be capable of self ferrying.

...snip...

~Jon
Hm, I was thinking about reusable lunar lander with decent crew accommodation. That would be an expensive machine - but it will be reused. The return capsule with heat-shield would go just to LX, no need to bring its heatshield into the Moon gravity well. It needs dv just to return to Earth. The lander will be shipped once (ok, there will be more, and they will be slowly replaced). The dv of the lander will be a bit (few hundreds m/s, for landing) more then enough to return from Moon to Lx. You are right that over time it will be contaminated with dust and what not, though.

The LX station in my eyes has propellant depots, empty stages (Centaurs), crew Moon landers, cargo Moon landers, perhaps deep-space ships (more shielding, provision for more supplies for long autonomous missions, perhaps a good suite of instruments to examine NEOs/Phobos whatnot), and Earth return capsules attached. And a habitat for the station crew and whatnot. All of this built incrementally, starting with the depot and a basic hub.

The crew arrives in Earth return capsule delivered by a Centaur, has a rest/party/meeting with the station crew, then switched to a 
a crew Moon lander attached to a fueled Centaur and lands on the Moon. Eventually it returns, switches to Earth return capsule and goes home.

When a cargo for Moon arrives (possibly using slow solar/nuclear electric/thermal tug) , it is re-mated to a cargo lander (ideally no EVA needed, just some robotic arm work, which should be doable with proper design; EVA only if something does not work as planned - station crew can save the day in many cases where all-automatics fail and would have resulted in mission loss). Having ready hardware and lots of fuel might allow 'rescue' missions of all sorts (not only saving astronauts, but perhaps also costly satellites  ending in wrong orbit).

I think doing it this way minimizes the amount of fuel and hardware spent on serious and sustained exploration. The initial costs are quite high - but if we are really serious about sustained exploration, something like this will eventually emerge.

Offline veedriver22

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Re: Propellant depot strategy & tactics pow-wow
« Reply #113 on: 08/28/2009 05:23 PM »
 Would it make any sense to have the Earth return vehicle ferried back to Earth by the centaur as well?

Offline Downix

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Re: Propellant depot strategy & tactics pow-wow
« Reply #114 on: 08/29/2009 04:41 PM »
I got to thinking of the Tanker Truck analogy that's been floating around here a bit.  Saying, "you want to drive to Mexico, you drive a tanker truck to Dallas in order to wait for you".  Good Analogy, but not workable here.  For that to work, we'd have to basically be launching the equivelent of a Space Shuttle main fuel tank in one go.  A closer analogy for us would be us sending a dozen Motorcycles, each one with a fuel tank holding 2 gallons in it.

Now, if we could figure out how to launch a SSMT on top of a large booster, then I'd be impressed.
chuck - Toilet paper has no real value? Try living with 5 other adults for 6 months in a can with no toilet paper. Man oh man. Toilet paper would be worth it's weight in gold!

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