Author Topic: An Alternative Lunar Architecture  (Read 597137 times)

Offline JasonAW3

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Re: An Alternative Lunar Architecture
« Reply #1420 on: 07/13/2014 11:57 pm »
That's a very good point gbaikie, load up your depot with say 6 shipments each of 25 tonnes O2, last shipment 25 tonnes H2 gives you 175 tonnes propellant in LEO, no need for a really big rocket.

Oh come on...
     We all KNOW that we want to see a monster like the ea Dragon with 500 to 600 tons of fuel launched to orbit!
My God!  It's full of universes!

Offline KelvinZero

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Re: An Alternative Lunar Architecture
« Reply #1421 on: 07/14/2014 01:55 am »
The boil off problem is why hydrogen will in practice be restricted to launch vehicles.  In space chemical rockets will probably burn a storable fuel like methane.

I would like to see a clear statement somewhere why boil-off won't be easily solved by active cooling.

On the other hand, perhaps hydrogen tanks are significantly more likely to develop leaks because of the greater cold, surface area, and (I think) the ease with which hydrogen slips through tiny cracks? boil-off can be at least budgeted for. A tank springing a leak could easily be catastrophic.

Offline Burninate

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Re: An Alternative Lunar Architecture
« Reply #1422 on: 07/14/2014 06:16 am »
That's a very good point gbaikie, load up your depot with say 6 shipments each of 25 tonnes O2, last shipment 25 tonnes H2 gives you 175 tonnes propellant in LEO, no need for a really big rocket.
This sequential LOX->H2 thing is a great idea.  That allows the use of hydrolox EDS stages up to quite large scale without any ZBO cryocooler tech at all.
« Last Edit: 07/14/2014 06:17 am by Burninate »

Offline Nilof

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Re: An Alternative Lunar Architecture
« Reply #1423 on: 07/14/2014 10:27 am »
For LEO depots you could also go for a bring your own hydrogen design. Make the depot LOX only, and launch the transfer stages filled with LH2 but without LOX. Fill them up with LOX at the depot/staging point.

This may be easier to develop as well, if it means you don't have to develop an LH2 pump for the depot.
« Last Edit: 07/14/2014 10:29 am by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline RanulfC

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Re: An Alternative Lunar Architecture
« Reply #1424 on: 07/14/2014 02:18 pm »
In terms of costs and ability such an EML-2 space station could function in LEO or in Mars orbit.

GBaikie, I assume you know this statement is false from front to back correct? The EML-2 space station FUNCTION is a "gateway" at the highest point in the Cis-Lunar gravity well so as to facilitate missions beyond Cis-Lunar space as well as supporting missions to the Moon itself. It can not perform this "misson" in either Martian or LEO orbits.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline gbaikie

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Re: An Alternative Lunar Architecture
« Reply #1425 on: 07/14/2014 08:03 pm »
In terms of costs and ability such an EML-2 space station could function in LEO or in Mars orbit.

GBaikie, I assume you know this statement is false from front to back correct? The EML-2 space station FUNCTION is a "gateway" at the highest point in the Cis-Lunar gravity well so as to facilitate missions beyond Cis-Lunar space as well as supporting missions to the Moon itself. It can not perform this "misson" in either Martian or LEO orbits.

Randy
I think in terms of focus that NASA should first have depot in 28 inclination of the KSC, next it should focus on exploring Moon and then explore Mars. A depot should not need a crew to function, but it's possible having crew involved in establishment of depot could a good idea- maybe. A crew is useful in terms of fixing
or debugging things.
Analogous is commercial lunar mining, one should include crew in the set up of mining operation, opposed to the idea of doing it only by robotic operation [which I believe adds complications and costs]. So one would set up a lunar mining operation with idea of using least amount crew for it's operation.
So in terms of depot, one may have crew going to it, but crew should not needed in order to transfer fuel
in terms operationally.

In terms of NASA missions sequence of focus, LEO, Lunar orbit, Lunar surface, followed by EML-2, and then either directly to Mars surface or Mars orbit, then Mars surface.  Or one could say EML-2 is more related to Mars than the Moon.
Or minimal requirements for Moon and Mars is depot in LEO and depot in Mars orbit- and L-points can be staging area, but don't require a station or depot.
The importance of NASA depot in LEO, is establish of system of economically explore the Moon, then Mars.
Or without depots in space, I see no purpose to exploring the Moon. Or commercial lunar mining requires the use of depots, and I think NASA should lower the risk involved by first operating depots is space. Or it's as essential step as NASA exploring the moon. Or NASA explores to Moon in order to lower risks and start up costs of commercial mining.
So right now for the Moon to be mined, the company would need to explore the Moon,  establish depots, and develop a market for rocket fuel in space. And that's a lot of up front costs- and with very vague future potential profit. And because all stuff needed begin, it is why we don't already have commercial lunar mining.
So NASA should establish the use of depots, as this leads to markets in space, and it's required for Mars exploration and it's required to lower Mars and Lunar program costs.

I am no fan of a NASA lunar base in near term- would no idea where to put one even if I was a fan. NASA needs find better locations on the Moon to commercial mine water. So potential commercial lunar miner would have survey of where are places to start lunar mining, and they would decide if there is actually minable water on the Moon. It makes no sense for NASA to decide this issue. So if one gets commercial lunar water mining, maybe near this location would a good location for a NASA lunar base.
But at that point in time, NASA would be [should be] exploring Mars, and whether NASA builds a lunar base is not important issue to address- at this time.
Nor I am a fan of NASA EML2 gateway station. Big fan of using L-points as staging area to get to Mars- but don't need  NASA EML2 gateway station. And if we had NASA EML2 gateway station, it seems it might be more useful at Mars orbit.
So I was saying one might have NASA station in LEO, which one could move to EML2, and then one move to Mars orbit. And such a station would be presumably be related to establishing NASA operations.
Though not big advocate of idea in general, just saying it's possibility as a path to go.
« Last Edit: 07/18/2014 09:10 pm by gbaikie »

Offline muomega0

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Re: An Alternative Lunar Architecture
« Reply #1426 on: 07/14/2014 08:56 pm »
ISRU is one of the main reasons why a lunar outpost is worth far more than an EML-2 station. On the long run, it may be cheaper as well, since it could potentially be self-sufficient in water, oxygen and propellant. 

An EML-2 station is a waste of taxpayer money.

Unless that EML-2 station is a fuel depot for interplanetary spacecraft. The fuel can come from the lunar outpost.

It seems a EML-2 station  and/or lunar outpost could be waste of tax payer money.
But I suppose, one should first ask what is the EML-2 station and/or lunar outpost. And how much would it cost the taxpayer.
How did you determine that the EML2 station would be a waste of tax payer money?  Yes, the concern is that the gateway could start to consume the budget much like everything else.

The L2 Gateway should be thought as the re-useable voyager, the DSH that is not stuck in one location--multiple destinations.

In the most optimistic program plan, the DSH is sent to L2 for one year with a few crew to demonstrate that both crew and hardware can survive the round trip to Mars.  The DSH is then reused for subsequent trips for satellite assembly and repair, ARM, and emergency lunar egress. Inspirational Mars skipped this step.

The issue of course is that crew health issues (and the technology) are not resolved to fit the mass and cost budget.  It's reasonable then to expect incremental improvements and duration to evolve to the ~ 1year trip duration.  How long and much will this cost?  While active shielding is trading better than passive, will it be the solution?  Can not one expect incremental technology improvements as the architecture moves toward reuse?  Why not send the crew for a 6 day lunar sortie to service say ISRU, then have a few of them return to DSH/L2 Gateway for a long duration stay prior to the return to earth--a dual purpose mission.   

Recall that the Gateway was added for two very specific reasons:  1) demonstrates that the "DSH" or the vehicle that houses crew for the trip to Mars can survive the 1 year trip 2) increases flight rate BEO while conducting crew health research in the proper BEO environment.  It was not meant to be a destination, but simply a stepping stone, but after considering the benefits of depots at L2 (not L1!) and L2 satellites, and High Lunar Orbits vs Low Lunar Orbits and minimum dV hit, and a reuseable LEO to lunar tug, etc, it appears to have quite a few benefits.  there are many disadvantages if the L2 depot and gateway are combined.

If it does take a decade or two to resolve BEO crew health mass and budget issues, then ARM would be welcome mission addition rather than having the 'gateway' sit at L2--set it on its way and explore--a trial mars mission.  But not the ARM that was hastily drawn up.

The alternative is lunar first, where all the cash is dumped into 6 day lunar sorties and ISRU with little focus on BEO challenges.   A careful balance must be achieved.  It starts with the LEO depot to reduce costs and allow substantial IP participation.
« Last Edit: 10/31/2014 01:35 pm by muomega0 »

Offline gbaikie

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Re: An Alternative Lunar Architecture
« Reply #1427 on: 07/17/2014 12:28 pm »
ISRU is one of the main reasons why a lunar outpost is worth far more than an EML-2 station. On the long run, it may be cheaper as well, since it could potentially be self-sufficient in water, oxygen and propellant. 

An EML-2 station is a waste of taxpayer money.

Unless that EML-2 station is a fuel depot for interplanetary spacecraft. The fuel can come from the lunar outpost.

It seems a EML-2 station  and/or lunar outpost could be waste of tax payer money.
But I suppose, one should first ask what is the EML-2 station and/or lunar outpost. And how much would it cost the taxpayer.
How did you determine that the EML2 station would be a waste of tax payer money?  Yes, the concern is that the gateway could start to consume the budget much like everything else.

The L2 Gateway should be thought as the re-useable voyager, the DSH that is not stuck in one location--multiple destinations.

In the most optimistic program plan, the DSH is sent to L2 for one year with a few crew to demonstrate that both crew and hardware can survive the round trip to Mars.  The DSH is then reused for subsequent trips for satellite assembly and repair, ARM, and emergency lunar egress. Inspirational Mars skipped this step.

I have not determined that the EML2 station would be a waste of tax payer money. But it certainly could be.

I would say as general note, and something learn able from ISS, is a need to determine how to have space stations have operational lifetime equal or greater than structures we have on Earth.
Or we need get to point of having space stations that have lifetimes of say, 50 years or more.
Being forced into a routine of  having 20 year [or less] lifetime disposable space stations, in general, makes the space environment less usable or realistic in terms a potential of opening the space frontier.

Or living on Earth would not work, if our structures only lasted 20 years. One could have grass huts last only a few years [which require couple days to make], but the Empire State and the Golden State bridge would not be built if they were to only last 20 years. One can't construct something which requires years [or costs billions] and then not have them last for very long.
So in terms of any other space stations, a primary focus should be related to preserving and learning how to have the ISS operate with a greater lifetime. Even if we ignore the very bad PR of crashing ISS into Earth, there is value in keeping ISS flying in order to actually learn how to live in space.

And another aspect of space stations is being able to operate them at low yearly cost. Perhaps if we end up, de-orbiting ISS, one might sell idea of EML2 station on basis learning from mistakes of ISS, in terms improving future space stations so they last longer and have less daily maintenance needed. Though not sure in wake of a crashed ISS, that Congress would have much confidence in such promises.
 
« Last Edit: 07/18/2014 09:13 pm by gbaikie »

Offline muomega0

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Re: An Alternative Lunar Architecture
« Reply #1428 on: 07/17/2014 01:48 pm »
ISRU is one of the main reasons why a lunar outpost is worth far more than an EML-2 station. On the long run, it may be cheaper as well, since it could potentially be self-sufficient in water, oxygen and propellant. 
An EML-2 station is a waste of taxpayer money.
Unless that EML-2 station is a fuel depot for interplanetary spacecraft. The fuel can come from the lunar outpost.
It seems a EML-2 station  and/or lunar outpost could be waste of tax payer money.
But I suppose, one should first ask what is the EML-2 station and/or lunar outpost. And how much would it cost the taxpayer.
How did you determine that the EML2 station would be a waste of tax payer money?  Yes, the concern is that the gateway could start to consume the budget much like everything else.

The L2 Gateway should be thought as the re-useable voyager, the DSH that is not stuck in one location--multiple destinations.

In the most optimistic program plan, the DSH is sent to L2 for one year with a few crew to demonstrate that both crew and hardware can survive the round trip to Mars.  The DSH is then reused for subsequent trips for satellite assembly and repair, ARM, and emergency lunar egress. Inspirational Mars skipped this step. there are some disadvantages if the L2 depot and gateway are combined.
I have not determined that the EML2 station would be a waste of tax payer money. But it certainly could be.
It should come to no surprise that engineers want a firm goal or destination and the resources to make it happen, with the door left open for future work, specifically a robust and vibrant space exploration program.  Congressional districts want this too.

Perhaps the name should be changed to L2 Demonstration Explorer (voyager?) rather than station or simply retain L2 Gateway--opens doors to a destination--it has removable, perhaps modular, parts.  IOW: never call it a station..after all its not a destination--The destinations are quite few:  cis-lunar, asteroids, Mars in the near term.

Given that it can serve a multipurpose function for crew health research, satellite and architecture assembly and servicing, lunar safehaven, mars and asteroid transfer vehicle, it may be priceless.  While it should be the goal to get right the first time and have it survive 50 years of deep space travel to the destinations, its more probable to see it evolve over time because of the challenges.

To move BEO, the present needs are quite adequately outlined in the NASA Space Technology Challenges.  The uncertainty in funding and solution time frames is why the term "flexible path" was chosen-folks were just being realistic, not to mention the debates on 'tactics'.

In the "capability driven architecture" the heritage hardware and approaches are not meeting up with the need for "a robust and vibrant" BEO program.  Recall that it was 3.7B for 6 flights to ISS.  You want something that lasts not 20 years, but 50!, yet almost the entire architecture is based on expendable hardware.  ???  In the careful balance between operations of old stuff and directionless honeypots of open ended research, retaining the heritage hardware would not be a detriment if there were resources left over to work and to demonstrate the future needs, but after a decade, time lag is the only plan forward--gradually shifting resources over a very long period of time--which is countered by 'stall tactics'. 

The plans presented over the last decade simply did not try to address the technology challenges for BEO (full GCR and micro g and a year in duration) and basically said lets head to the moon (half GCR and 1/6th g for a few weeks to a few months) and explicitly stated that the architecture stripped technology development in order to explor' sooner and that this plan prepared NASA for Mars.

I would say as general note, and something learn able from ISS, is a need to determine how to have space stations have operational lifetime equal or greater than structures we have on Earth. Or we need get to point of having space stations that have lifetimes of say, 50 years or more. Being forced into a routine of  having 20 year [or less] lifetime disposal space stations, in general, makes the space environment less usable or realistic in terms a potential of opening the space frontier.

Or living on Earth would not work, if our structures only lasted 20 years. One could have grass huts last only a few years [which require couple days to make], but the Empire State and Golden State bridge would not be built if they were to only last 20 years. One can't construct something which requires years [or costs billions] and then not have them last for very long.
So in terms of any other space stations, a primary focus should on preserving and learning how to have the ISS operate with a greater lifetime. Even if we ignore the very bad PR of crashing ISS into Earth, there is value in keeping ISS flying in order to actually learn how to live in space.

And another aspect of space stations is being able to operate them at low yearly cost. Perhaps if we end up, de-orbiting ISS, one might sell idea of EML2 station on basis learning from mistakes of ISS, in terms improving future space stations so they last longer and have less daily maintenance needed. Though not sure in wake of a crashed ISS, that  Congress would have much confidence in such promises.
Technology to reduce IMLEO and decrease maintenance?!   wow, where do you come up with these wacky ideas?   So outline the technologies that would be incorporated into ISS that would extend the lifetime without maintenance--actually this has already been done and some implemented and yet it still costs billions to operate ISS.  The great ones, IMHO, were left in paper mode--possibly too risky?

The key is to alter the approach--shift resources away from ISS but keep it safe.  It all starts with a LEO depot and L2 Gateway station voyager.

The next generation appears to be quite excited by this flexible balanced plan forward: they can learn the lessons from the past as they take the hopefully next giant leap forward.

Offline Robert Thompson

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Re: An Alternative Lunar Architecture
« Reply #1429 on: 07/17/2014 03:19 pm »
http://www.astrowatch.net/2014/07/japanese-government-plans-to-land-probe.html

Someone should put a fork in no plant a consortium fabric identity pole no locate the centroid of a sphere of PC non-interference uh land a mission in the best yet prospect for lunar ISRU, Cabeus. Even if it is a ragged band of rebels using heritage hardware, used staples and abc Wrigley's.

Offline Robert Thompson

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Re: An Alternative Lunar Architecture
« Reply #1430 on: 07/17/2014 03:46 pm »
One could also ship Hydrogen ice and arrive at destination with liquid Hydrogen.

I really enjoy this forum.

Offline KelvinZero

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Re: An Alternative Lunar Architecture
« Reply #1431 on: 07/18/2014 03:37 am »
One could also ship Hydrogen ice and arrive at destination with liquid Hydrogen.

I really enjoy this forum.
This is something I dont understand but there is apparently a simple answer to. What does limit the sorts of temperatures you can reduce your tank to? How long would it take to heat up again?

Offline Robert Thompson

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Re: An Alternative Lunar Architecture
« Reply #1432 on: 07/18/2014 07:25 pm »
My mind went to an evolved ULA IVF ACES, with a high pressure tank for solid hydrogen symmetrically enclosed inside a (now proportionately) smaller LH2 tank in a common wall LO2/LH2 configuration, using LHe2 as a pre-flight pre-cooler. I might elaborate. It's probably perfectly impractical.

Offline gbaikie

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Re: An Alternative Lunar Architecture
« Reply #1433 on: 07/18/2014 08:00 pm »
One could also ship Hydrogen ice and arrive at destination with liquid Hydrogen.

I really enjoy this forum.
This is something I dont understand but there is apparently a simple answer to. What does limit the sorts of temperatures you can reduce your tank to? How long would it take to heat up again?

There is probably is not simple answer regarding Hydrogen ice:
"Introduction. Hydrogen is probably the most extensively studied form of matter that exists (e.g. [1], [2] because many of its important properties can be predicted theoretically from first principles, and because these results can be compared with experimental data. The theory of hydrogen has often functioned as a testbed of general theories of atomic and molecular behavior. Not withstanding all of this work, most of the common mechanical properties of solid molecular hydrogen are beyond calculation, in part as a result of the non-ideality of the macroscopic crystal."
http://www.tvu.com/PEngPropsSH2Web.htm
And:
"The description of molecular hydrogen is complicated by the existence of macroscopic crystals characterized by different nuclear spin states; parahydrogen has its nucleon spins antialigned, and orthohydrogen has nucleon spins aligned. The stable relative concentration of these states is temperature dependent; 75% of hydrogen is orthohydrogen at room temperature (defined as "normal" hydrogen) whereas equilibrium solid hydrogen is almost pure parahydrogen."
And:
"Solid hydrogen has many peculiar properties as a result of its single proton and electron atoms. The solid is a translational quantum solid, where the atoms are not localized at T = 0 K [2]. It is also relatively highly compressible - by 100% at 10 kbar."
[[ 10 kbar equals: 145,037.7 psi]]

So as I understand it, to form solid hydrogen requires a long time, and to transform from frozen  parahydrogen to orthohydrogen also requires a long time. Or chart show in above ref indicates 4500 hours
[187.5 days] to go from parahydrogen to orthohydrogen. Because: "Hydrogen has a triple point temperature of 14 K and a triple point pressure of 0.070 atm (54 torr) [3]. Condensation from the vapor to the solid is naturally relatively slow because of these low pressures."
Or it seems takes long time to form crystals and it seems there is variation of crystals [size or structure].

In terms of specific heat, hydrogen gas is very high and hydrogen liquid is also high: 9.78 kJ/kg K:
http://www.technifab.com/cryogenic-resource-library/about-liquid-hydrogen.html
And water which is has a high specific heat, is about 4.18  kJ/kg K.
So water and LH require a lot heat to change their temperature, though unlike water, I don't think it takes much energy to change from state of ice to liquid hydrogen. Of course at such low temperatures, one is dealing low amount of energy [so comparatively it might be a lot]. So would say to make Hydrogen ice it's more about time that being cold rather the energy needed to make it cold, and with ambient temperature of 30 to 50 K in dark craters of Moon, it should be somewhat easier to do.

Now, I can't remember which form of hydrogen one wants for rockets- but it matters whether the hydrogen is parahydrogen or orthohydrogen. And hydrogen gas or liquid could be either.

Edit: Oh, ok, you want it parahydrogen, so ice not a problem in this regard:
wiki: Liquid hydrogen consists of 99.79% parahydrogen, 0.21% orthohydrogen
And continuing from wiki:
"Room temperature hydrogen consists mostly of the orthohydrogen form. After production, liquid hydrogen is in a metastable state and must be converted into the parahydrogen isomer form to avoid the exothermic reaction that occurs when it changes at low temperatures, this is usually performed using a catalyst like iron(III) oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromium(III) oxide, or some nickel compounds."
http://en.wikipedia.org/wiki/Liquid_hydrogen

So to have remain in parahydrogen state could be somewhat problematic in terms of long term storage, and starting with it being ice should make it easier.


« Last Edit: 07/18/2014 09:27 pm by gbaikie »

Offline TrevorMonty

Re: An Alternative Lunar Architecture
« Reply #1434 on: 08/30/2014 12:00 pm »
Thanks Sdsd for the links.

I've read the DTAL paper before, its the basis of Masten XEUS lander, but haven't see the paper on fuel depots.

ULA has some good ideas, but most of the hardware seems to be expendable, which is great if you are manufacturer of ACES stages. With large fully reusable LV eg Space BFR which maybe delivering 100mt+ of fuel at a time, these fuel depots start making sense. The tanker that delivers fuel to L2 also needs to be fully reusable, ie returns  to LEO using aerocapture.  If the fuel costs are lower enough it may end up being cheaper to reuse lander and deliver lower mass to lunar surface at a time.

I do like the idea of using the surplus fuel in lander to provide power and life support for extended stays. One of the biggest issues of extended stays is power to survive a lunar night.

I think getting fuel to the region of the Moon and reusing that hardware will be the first challenge we solve.  Next we have to figure out how to move the reusable vehicles to Earth LEO so that they can be refueled in LEO (i.e. aerocapture, the static drag device that's been mentioned, etc.).  After that the challenge is to figure out how to make a reusable Earth-LEO bulk transportation system - which even if it's water will likely be pretty hard (i.e. costly to develop and prove out).

So I would concede that we'll have to live with disposable systems for quite a while, but decreases in launch costs and standardizing the construction of the fuel transports could make it affordable enough to implement.

This is a better thread to reply on, I didn't want to hijack the Disposable Lunar Descent Stage thread with architecture discussions.

The first lunar base and transport system is going to be wholly dependent on Earth fuel. Even with cheapest LV currently available ie FH each trip is going to be very expensive.
 Based on ULA paper  (http://www.ulalaunch.com/uploads/docs/Published_Papers/Exploration/AffordableExplorationArchitecture2009.pdf) a reusable lander will need about 40t at L2 this equates to 100t at LEO Depot. So one lunar landing will require 3xFH, two for the lander fuel and one for the payload/passengers. That is $500M a trip for the FH launches.

If a reusable BFR can deliver a single trips worth of the fuel (120t in LEO) for  $1000Kg then the only additional launch would be a F9R to LEO with payload/passengers for $60M. We are now talking $160M in launch cost per trip to lunar surface.

NB ISRU doesn't need to produce a lot of fuel to make large savings. A few tons of LO2 available on surface for the lander would reduce the LEO fuel requirements by tens of tons per trip.
eg The Masten XEUS would need about 40t of fuel to delivery 5t to surface and return to L2. If the lander can refuel on surface it only needs about 10t to land 5t and a top up of approx 10t to get back to L2. That 10t of ISRU fuel means 30t less fuel required at L2 which equates 75t less fuel required at LEO.
With surface fuel available the lander can be made considerable lighter reducing the fuel requirements even more. 


Offline A_M_Swallow

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Re: An Alternative Lunar Architecture
« Reply #1435 on: 08/30/2014 12:58 pm »
The SLS is currently officially rated as having a 70 metric ton payload.  I do not know if any of the recent changes will increase the payload to 100 tonne.

To transfer 100 tonne in ~4 hours with a fuel having a density of 1.14 kg/litre would need pumps able to pump
(100 tonne * 1000 kg/tonne) / (1.14 kg/litre * 4 hours * 60 minutes) = 366 litres per minute

There are off the shelf pumps that can do 320 litres per minute that require 1000W, so that part is doable.

Offline M129K

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Re: An Alternative Lunar Architecture
« Reply #1436 on: 08/30/2014 07:21 pm »
 
The SLS is currently officially rated as having a 70 metric ton payload.  I do not know if any of the recent changes will increase the payload to 100 tonne.
The payload of a Block 1B SLS is ~93 metric tons with the baselined RL-10 engines and 105 tons with a J-2X, so 100 tons is not completely unrealistic. The official baseline of the intermediate SLS is still 105 tons to LEO, and that's the SLS supposed to do all missions.

Offline TrevorMonty

Re: An Alternative Lunar Architecture
« Reply #1437 on: 08/30/2014 07:47 pm »
Any near term (10yr) lunar base is most likely to be a commercial venture eg Bigelow. To be viable its going to have rely on commercial LVs.

Offline RanulfC

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Re: An Alternative Lunar Architecture
« Reply #1438 on: 09/02/2014 03:11 pm »
Any near term (10yr) lunar base is most likely to be a commercial venture eg Bigelow. To be viable its going to have rely on commercial LVs.

How so? Given there isn't really a business case to support such an effort unless it was "paid-for" by a government agency. Bigelow has yet to "prove" a case for LEO business let alone BLEO.

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline redliox

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Re: An Alternative Lunar Architecture
« Reply #1439 on: 09/04/2014 05:25 am »
One could also ship Hydrogen ice and arrive at destination with liquid Hydrogen.

I really enjoy this forum.
This is something I dont understand but there is apparently a simple answer to. What does limit the sorts of temperatures you can reduce your tank to? How long would it take to heat up again?

Whatever you do don't warm up that tank with a match...  :o
"Let the trails lead where they may, I will follow."
-Tigatron

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