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#51 2006-06-06 07:07:43

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...on Lunar Orbit being unstable as well putting a space station there is...

full answer to this and other points in my posts on the SpaceNut's thread about the Lunar Space Station www.newmars.com/forums/viewtopic.php?t=4724

.

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#52 2006-06-06 07:21:20

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...the Moon to rotate...

the Moon don't rotate on itself...  smile  smile  smile  all the LSSs must be placed to equatorial orbits and (both) the CEV and LSAM will have (ESAS plan) some extra-fuel to change its orbit (and, the LSAM, to land in different places)

probably they can't go on the moon's poles from the LSS but can explore in a 1000+ km. range up/down the equatorial line

Why would you want to do maintenance on the LSAM in orbit? Wouldn't it be much easier to do that on the ground at the Lunar base?

right... I say that in my posts on the SpaceNut's thread

why can't a tanker dock directly with the orbiting LSAM, skipping this station business altogether?

that is a poor version, without the great advantages of the LSS like... have a safe place to live (for the astronauts that will accomplish many missions per year!)

.

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#53 2006-06-06 07:25:49

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

So to distill all your arm-waving and disjointed lines:

  • 1-A Lunar station would be needed to save the crew if the CEV failed after launch from the Lunar surface
    2-A lunar station would be needed to save the crew if the LOI burn on the LSAM fails
    3-A Lunar station is ideal for staging multiple surface trips using reuseable landers, with a surface radiation shelter to save the mass of one on the station.

Maybe I should have said they were disjointed lies instead, it would have been more accurate.

First of all, the CEV will almost certainly work, because it will had to have worked for the mission to have been mounted in the first place, and the chance the CEV will  just spontainiously die only a week in Lunar orbit is negligible. This really just isn't a problem.

Second, you assume that the only way to return to Earth in the event the LSAM's LOC burn fails is to decelerate to Lunar orbital velocity (LOC) then re-accelerate to Earth-return velocity (TEI). Why would you have to do that? The TLI burn will, like Apollo, put the CEV/LSAM on a free-return trajectory so if they don't perform the LOC burn they will slingshot around the Moon and return to Earth, without burning a drop of fuel. And if this is not the case, then the CEV will should have enough fuel to change its trajectory for a slingshot maneuver too. This too is a non-problem.

So, that pretty much shreds the safety arguments for a station. Now about using it as a staging area for reuseable LSAMs to perform multiple missions:

The problem with this plan is fuel: that is, you don't have enough. It takes large amounts of fuel to land and launch to the Lunar surface, and comprises the majority of the LSAM's mass. And this is with burning Hydrogen for decent, which you can't store in orbit, and with disguarding the decent stage.

And if you want to actually accomplish anything on the Moon, you need to bring some equipment with you (rovers, drills, telescope parts, etc) which the ESAS plan calls for leaving behind. It takes even more fuel to bring these off the surface and return them to Lunar orbit for reuse.

A whole HLLV flight worth of fuel would probably be enough for only two trips worth of Methane/Oxygen fuel I would estimate, and you would need a tanker vehicle to bring you that fuel in the first place. This tanker would have to perform an LOI burn, maneuver to the station, and dock with it to transfer its fuel... which will be about the same complexity as the LSAM, and you can't reuse the tanker!

And you wail and moan about the evils of development costs, when this tanker would have to be developed in addition to the LSAM. Plus, I don't buy your estimated figure for the Lunar space station development, it just can't be done for that kind of money. The pressurized ISS modules cost a little over a billion each in 1990's dollars, and they don't have power/cooling or the required stationkeeping engines.

The extra fuel cost for the station would be tremendous too, because it will take alot of fuel to maintain an unstable orbit for months in Lunar orbit, alot more then you think. Or, if the station is based at the Lagrange point, then you will need extra fuel for the LSAMs to make the longer trip to/from the surface. You can't win. Plus, basing the Lunar station in orbit would mean you either can't go everywhere on the surface (equitorial orbit) or else you can't go everywhere any time you want (polar orbit).

...Which you would need to reach this hypothetical radiation shelter on the surface. So either we give up being able to go to the Lunar poles, where the ice and perminantly lit mountains are, or else you take a huge risk the astronauts will die since their orbit doesn't take them over this radiation shelter. And this is assuming that you can jump in your LSAMs and get down there in time, which I don't think you can. This is unacceptable.

If we do want reuseable landers, then the best place to put them is on the Lunar surface. I think it will take only three or four LSAMs worth of cargo to build a LOX factory, and the radiation shelter will be "on site" as it were. Put the fuel depot and base there, and skip the Lunar station alltogether.

Plus, if you are already on the Lunar surface and you want to make multiple trips all over the surface from there, then it will take far far less fuel since you are only going suborbital instead of having to deorbit/reorbit completly to the Lunar space station in orbit or at Lagrange. And, since the majority of the propellant will come from the Moon already, then it will take even less.

I think that this pretty well dooms the case of a hypothetical Lunar space station


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#54 2006-06-06 08:25:45

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...First of all, the CEV will almost certainly work...

First of all... is BETTER to HAVE a (6+ months extra life) LSS in lunar orbit and a (6+ months extra life) Crew Habitats on the moon than DON'T HAVE them... ask the astronauts that will REALLY fly and RISK their life (since a moon mission is a "little more" dangerous than write angry posts on a board...)

...problem with this plan is fuel: that is, you don't have enough...

"tanks and fuel" are only part of the total LSAM weight (around 40%) and a little part of the LSAM costs (probably less than 10%) then, every reusable LSAM will be a 60% of weight and 90% of value SAVED

send the LSAM tanks/fuel to the LSS don't need "many" CaLV but only ONE launch every 4+ moon landings,,, because they don't need to launch the full CEV/SM/LSAM system but only the tanks and the engine/fuel for LOI... don't forget that a 70 mT CEV/SM/LSAM system will use the LSAM engines and a little part of its fuel for LOI, then, great part of the CaLV payload will be "usable fuel"

the fuel don't need to wait years around the moon but only a time close to (or less than) the CEV's fuel (six months) max life

...and moan about the evils of development costs...

why this "evil" never appear when NASA build two rockets in 15 years instead of one rocket in seven years...???

however, the Billion$$$$$$$$$ saved EVERY YEAR with the reusableLSAMs+LSS will be so many that NASA may use the saved funds to launch New York around the moon...

...Lagrange point...

I've never suggested that

...assuming that you can jump in your LSAMs and get down there in time...

certainly LESS time than come back to earth...

...make multiple trips all over the surface from there...

as I've already suggested, the surface-only exploration is safer and cheaper, but needs time and money to launch many vehicles on the moon, etc.

it may happen within 10 years from the exploration restart... in the early years the only way for multiple missions is the LSS

.

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#55 2006-06-06 10:58:01

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

As you have perpetually ignored, there is a such thing as an acceptable risk of failure, and there is a such thing as a safety measure which is not worth the expense. A lunar space station is just such a thing, that the CEV will have had to have worked before the mission even leaves Earth orbit, and the LSAM's decent module will have to work for the CEV/LSAM to enter Lunar orbit (as opposed to free-return back to Earth). The only thing that won't be tested before it life-or-death has to work is the LSAM acent engine, and if it doesn't work, you can't flee to the Lunar space station. Even if you could, why would you want to when you could return to the CEV for a ride home instead?

Your figures for the LSAM weight are all wrong, fuel accounts for around 75% of its mass, and you can't possibly do any better since you can't burn Hydrogen and you have to lug the surface equipment back to Lunar orbit. No no, it will infact be much worse, like >90% of the LSAM will have to be fuel. So, you are only saving ~10% of the mass, and each CaLV would only be able to deliver fuel for two missions tops.

The LaGrange point is the only point where you can put a station near the Moon that is relativly stable, there are no stable Lunar orbits. Since fuel for correcting for this unstable orbit is a problem, putting the station at LaGrange is logical, but it requires more fuel to ferry back and forth from the surface. More time too.

And you can't store Hydrogen for six months, even Methane for six months is pushing it.

And it doesn't matter where you go during a solar flare if you can't get there in time, Earth or a Lunar radiation shelter.

And you are wrong, a Lunar orbit based exploration plan will take more launches, not fewer, because of the trouble of importing all the fuel.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#56 2006-06-06 11:19:35

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

Oh, and I forgot to mention, that there isn't going to be a "super CLV" powerful enough for the CEV to carry TLI and LOC fuel, it isn't happening. You would have to make two seperate launches, one for the "mini-EDS" and one for the CEV, which like the ESAS plan the CEV will have to be launched within a month or two before the fuel boils off.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#57 2006-06-06 14:33:18

RedStreak
Member
From: Illinois
Registered: 2006-05-12
Posts: 541

Re: Reusable LSAM

SpaceNut's thread

why can't a tanker dock directly with the orbiting LSAM, skipping this station business altogether?

that is a poor version, without the great advantages of the LSS like... have a safe place to live (for the astronauts that will accomplish many missions per year!)


...that's the same line they fed with Space Station Freedom which has mutated into the atrophied project known as the ISS.

Given the choice I vote for the more direct tanker approach.  Maybe keeping everything either in LEO or directly on the Moon is the best option.

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#58 2006-06-06 15:20:21

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...fuel accounts for around 75% of its mass...

no, it will be not 75% but (probably) around 60-65% in the expendable-LSAM

but you forget that, the expendable-LSAM, must brake (with its engines and fuel) the 70+ mT CEV/SM/LSAM from earth escape speed to LOI !!!!!

a giant (and fuel-costly) work that a reusable-LSAM must do only ONE time, when it come from earth and docks to the LSS !

the REUSABLE-LSAM must load and burn only the fuel for the LSS-moon-LSS travel... a few hundreds km. only with 1/6 of the earth gravity!!!

then, the fuel mass of a reusable-LSAM will be around 40% of the total LSAM weigh, or LESS

...for two missions tops...

the most payload-efficient reusable-LSAM must use refuelable tanks and I think it's not impossible to develop it in the next 15 years (if NASA wants, of course)

the LSAM will have an "hole" to put the fuel in the tanks, they only need to modify it for an in-space refueling

and, since the reusable-LSAM needs LESS fuel, one CaLV can send the fuel for 3/4 moon missions!!!

...can't store Hydrogen for six months...

the fuel don't need to be stored for six months or years in lunar orbit!

the crew on the LSS may accomplish FOUR moon missions in LESS THAN two months (much less than the 95-days earth orbit max loither time of the EDS with its giant LOX/LH2 tanks!!!)

the problem is that you use the WRONG measure-units to evaluate/compare the different moon missions

if we talk about how to transport potatos or scrap iron, the right measure units may be the WEIGHT

but if we talk of the most expensive activity of the world, the right measure units is MONEY ($$$$$) or (best!) the "number of exploration-hours/payloads/missions/vehicles we have for a given amount of money"

it's very easy to demontrate that you are WRONG, with a simple example...

sinche we don't know the (REAL) 2020 costs of the CaLV, LSAM, etc. we must use little and simple "nominal" figures/prices

also, we assume that, since the costs of the vehicles will be incredibly high compared with the cost of the fuel, the fuel don't counts for its price but only for its weight

I start from these "nominal" figures/prices:

- CaLV/EDS unit/launch cost: $1000

- LSAM unit cost: $1000

- single module LSS build/launch cost: $2000

but the LSS will be used for 100+ moon missions, then, the shared cost for 20 missions will be $400

- extra costs to develop the LSAM refueling tanks: $1000

- CEV/SM/CLV unit/launch cost: $300

- CEV/superSM/superCLV unit/launch cost: $400

- max landings of a reusable-LSAM: 10

- max LSAM-refuels sent with one CaLV: 4

- number of missions of the costs-evaluation: 20

the rocket used to send the LSAM-refuels don't counts... one $1000 rocket with 4-refuels will be the same of two $500 rockets with 2-refuels each

the compared costs are...

>>> 20 moon missions with expendable-LSAMs may cost:

20 LSAMs x $1000 = $20,000

20 CaLV/EDS x $1000 = $20,000

20 CEV/SM/CLV x $300 = $6,000

Total costs of 20 (100% expendable) moon missions = $46,000

>>> 20 moon missions with reusable LSAM may cost:

twenty missions' (shared) cost of the LSS = $400

2 reusable-LSAMs x $1000 = $2000

reusable-LSAM extra R&D costs = $1000

2 CaLV/EDS to launch the LSAM x $1000 = $2000

5 CaLV/EDS for LSAM-refuels x $1000 = $5000

5 CEV/superSM/superCLV unit/launch cost x $400 = $2000

Total costs of 20 (reusable-LSAM) moon missions = $12,400

only 27% of the costs than 100% expendable "single-use" vehicles !!!!!!!!!!!!!!!!!!!!!

with the reusable-LSAM we can accomplish up to FOUR TIMES more moon missions with the SAME FUNDS !!!!!!!

.

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#59 2006-06-06 16:51:30

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

Idiot, it doesn't matter how you get the fuel to the Moon, either in large loads a few times for reuseable landers or in smaller loads with expendable ones, for a given mass of fuel it requires the same fraction to slow it down into Lunar orbit, the only thing different is the mass of the fuel tanks. The bigger the mass you are trying to brake into Lunar orbit, the more the fuel you have to burn for LOI, its a percentage of the total mass and not the same. And, as you have advertised loudly with colored text, you want to ship it to the Moon in small tanks which have horrible mass efficiency.

And whether its 60-80% for the expendable mode is irrelvent, because you will be carrying much more dead weight to Lunar orbit (decent structure, surface equipment) and you won't be burning Hydrogen for the decent like the ESAS plan. Both of these will radically decrease the efficiency and your dry mass fraction, so there is no possible way even the CaLV could deliver enough fuel for more than two trips of a reasonably equipped LSAM.

Hydrogen fuel probably isn't going to work since if you are manning a Lunar base on the surface, then they won't be able to return to orbit unless picked up by a lander sent from the station. Trouble is, the station will have to be equitorial to do this on a timely fasion, and if the base isn't then you can't. Also, the station will require regular orbital correction, so it will need a continuous supply of rocket fuel. You want to lug both Hydrogen and Methane to the Moon?


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#60 2006-06-06 17:15:04

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...Idiot...

you can repeat your insults thousands times... nothing change

...two trips...

one CaLV launch can't send only two LSAM refuelings since the CaLV's payload (without the CEV/LSAM LOI fuel) is (about) 4 times the weight of the remain LSAM fuel, after LOI

also, since the fuel cost is minimal, TWO refueling per CaLV still are VERY CHEAP

5 more CaLVs x $1000 = $5000 + $12.400 = $17,400 ...about 35% of the total costs with expendable-LSAMs

that because the WEIGHTS of a LSAM are 40% vehicle and 60% fuel, but the COSTS are 99.9% vehicle and 0.1% fuel!!!

send TWO vehicles for 20 missions instead of TWENTY is a GIANT saving of money, no matter if the CaLV will send two or three or four refuelings

.

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#61 2006-06-06 17:45:03

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

More flailing and stupidity

First you say that we can't estimate costs, then you go and... estimate costs! Speaking of estimates, your numbers are insane and obviously biased to your opinion, such as the LSAM costing just as much as the whole CaLV.

And you completly ignore the fact that a "super CLV/CEV" isn't going to happen, and you ignore the development but more importantly the reoccuring cost of the tanker needed to get the fuel to the Lunar station.

And you completly ignore the fact that your lander simply can't be as fuel-efficient as the ESAS LSAM because it has to return its surface payload (rover, drill, etc) to orbit after each surface excursion. Combine this with not being able to burn Hydrogen for decent, and it will easily double the mass of the lander.

And you completly ignore the problem that small Hydrogen tanks will boil off fast because of their increased surface area versus bigger tanks, which is one reason that the EDS could loiter for months but little tiny lander tanks can't. The LSAM tanks called for in the VSE are rather large by comparison to the little single-use "cartridge" tanks you are talkinga bout I imagine.

And while the cost of fuel is trivial, the cost of importing the fuel will simply ruin the economics of your plan. The extra CaLVs/CLVs, the tankers, and development will eliminate the cost bennefits of reuseability so long as all the propellant has to come from Earth. This is so obvious, you must be a complete moron to argue that it is not so.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#62 2006-06-06 18:50:44

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...then you go and... estimate costs...

no, I don't estimate costs... it's only a comparison between two architectures using the same figures

...such as the LSAM costing just as much as the whole CaLV...

probably will costs MORE than a CaLV due to its complexity, 100% new parts and a few units built

but, if it will cost less, that don't change so much!

TWENTY vehicles will ALWAYS costs TEN times TWO vehicles!!!!

...a "super CLV/CEV" isn't going to happen...

why not

we are only in the early days of a 15 years trip....

...its surface payload (rover, drill, etc) to orbit after each surface excursion...

the LSAM has the extra tanks' space of the (unused) LOI fuel and the max hardware payload (2 mT) is around 5% of the total LSAM+fuel weight

...small Hydrogen tanks will boil off fast because of their increased surface area versus bigger tanks...

you forget that (ALSO) the (small) LSAM tanks/fuel will be designed to wait up to 95 days in earth orbit with the EDS...

in lunar orbit they must wait only a few days (after a new refuel) to land on the moon

...single-use "cartridge" tanks...

they can't be smaller than a standard tank, since they must load the same amount of fuel

...simply ruin the economics of your plan...

no

it is one of its winning points...

simply, because, dispatch four books with ONE box will ALWAYS costs less than dispatch them separately...

.

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#63 2006-06-06 19:33:53

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

But you do estimate costs, because you generate a figure (what was it, 27%?) of how much your plan will cost versus what the ESAS plan will. You made assumptions about the expense per unit and of development in your comparison. That is an estimate.

The LSAM just isn't going to be that expense. The decent stage engine will almost certainly be the venerable and inexpensive RL-10 or the new simplified RL-60. The life support and probably the computers will be CEV-derived, as will the fuel tanks perhaps. The acent engine will be based directly from the CEV service module too. The rest is structure, landing sensors, and software. Even lacking a heat shield, I bet each copy of the LSAM will cost no more (perhaps less) then the CEV capsule.

And yes, two reuseable LSAMs will cost more than twenty (provided you can get 10 missions each out of the reuseable one), but what of the other costs? For it to be so reliable, it will have to undergo more signifigant development, which might even include billion-dollar test missions to the Moon. How many LSAMs will that buy?

And what about the fuel? If you can only get two trips on one HLLV worth of fuel, then what do you really save when you include the cost of developing and throwing away the tanker that will be needed to bring the fuel from LEO to LLO.

And if you are shipping cargo to the Moon, like we will for a Lunar base or a darkside telescope, each flight will need its own HLLV anyway.

There will be no super-CLV because to push the CEV to the Moon you need a roughly equal massed EDS stage (hydrogen burning). There is no possible way that the CEV will drop in mass by more than half, and there is no possible way the CLV will more than double. Your suggestion otherwise is extremely ignorant and blatantly thoughtless.

And you warbaling that the surface payload is only 5% of the total mass is equally stupid, since for every tonne you have to launch off the Lunar surface you need roughly three or four tonnes of rocket fuel. Thats 8-10MT of mass you just added to your LSAM.

But your LSAM won't be waiting "just a few days," because it will take up to a week at each site and a few days to turn around, which will add up to about two months by your account. And yes, your "cartridge tanks" very well will have to be smaller then the ESAS fuel tanks, since they have to be small enough for robot arms or suited astronauts to handle. Robot arms have the nasty habit of snapping off if overloaded.

Books? You are an idiot, and your pathetic examples only reinforce this

Edit: And don't forget, your station will need many tonnes of fuel a year to keep from falling out of the sky and making a new crater on the Moon, and that will have to sit in storage tanks for some time between burns. Can't use Hydrogen for that, which will increase this fuel penalty even more.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#64 2006-06-06 20:18:50

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

And you want to talk plans?

How about a surface base, with occasional loads of imported Hydrogen from Earth to combine with LOX from the Lunar soil to make suborbital "hops" over the surface for short-term exploration. You couldn't reach the entire surface, but you could reach a signifigant portion of it, and this would be handy for prospecting a few major impact sites or servicing a telescope that is too sensitive to be mounted near the base.

Each tonne of Hydrogen you bring can be matched with 5-6 tonnes of LOX produced on the surface, so a 15MT load of Hydrogen from Earth means ~100MT of propellant, which would be sufficent for many hops or a few trips to/from Lunar orbit. These would be short enough that the chance of being caught in a solar flare would be very low.

At the base, you would have relativly roomy accomodations, gravity, and superior protection from both cosmic rays and solar flares, the former of which may turn out to be more dangerous then currently believed.

No space station required


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#65 2006-06-06 20:26:33

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,180

Re: Reusable LSAM

And you completly ignore the fact that a "super CLV/CEV" isn't going to happen, and you ignore the development but more importantly the reoccuring cost of the tanker needed to get the fuel to the Lunar station.

I would lump this into the costs of a continous base being manned. Importing hydrogen probably will be a must so we need to find a solution if costs would kill any permanently manned base. For a base an unmanned LSAM will hopefully be in the cards for just this purpose.

Edit :
you got your new entry in while I was typing mine up...

The decent stage engine will almost certainly be the venerable and inexpensive RL-10 or the new simplified RL-60.

I like the suborbital "hops" to allow for a large selection of site in one visit.

Are these engines capable of multiple firings.

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#66 2006-06-06 21:27:07

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

RL-10 has been used for years in all the EELVs, many of the Atlas-II/III, and some of the Titan-III/IV rockets. It has a good sucess rate and is probably the most refined small cryogenic engine ever. Since it was intended for upper stages, it is restartable, and was used in the DC-X "hover-rocket" demonstration that sucessfully demonstrated its good throttle control for landing.

Edit: It is rumored that they are good for at least ten firings.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#67 2006-06-07 03:18:54

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...you generate a figure...

we can change the price, multiply it as we like and talk of different objects... a REUSABLE spacecraft, car, airplane, PC, wash machine or everything ALWAYS cost 1/3, 1/4, 1/10 or less than EVERY expendable version

...The LSAM just isn't going to be that expense. The decent stage engine will almost certainly be the venerable and inexpensive RL-10 or the new simplified RL-60. The life support and probably the computers will be CEV-derived, as will the fuel tanks perhaps. The acent engine will be based directly from the CEV service module too. The rest is structure, landing sensors, and software. Even lacking a heat shield, I bet each copy of the LSAM will cost no more (perhaps less) then the CEV capsule...

you forgot... "and NASA will buy them in kit from an hobby magazine"

...two reuseable LSAMs will cost more than twenty...

pure madness

...then what do you really save...

"simply"... 99.9% of the unit price of each LSAM (...many Billion$$$$ in total...)

destroy the very expensive LSAM it's like scrap a NEW car, only a WEEK after buying it, when the gasoline in its tank ends...

the only difference is that one LSAM will costs like 3000 Rolls-Royce Phantom...

...roughly equal massed EDS stage...

of course

compared with the CEV/SM/LSAM weight, the "superCLV" must lift around 60 mT including its EDS... and there are infinite configurations to build that rocket

...only 5% of the total mass...

they are simply the ESAS (planned) LSAM/tools weights

...for every tonne you have to launch off the Lunar surface you need roughly three or four tonnes of rocket fuel...

the Apollo LM ascent-stage total weight was 4.5 mT of which 2.3 mT was ascent-fuel, then... payload:fuel is 1:1 not 1:4 ...the LSAM will use the same physics' laws and lunar gravity (both unchanged from Apollo era)

...won't be waiting "just a few days," because it will take up to a week at each site and a few days to turn around...

right

and the total wait time of the reusable-LSAM fuel will be up to 97 days LESS than the expendable-LSAM sent from earth

reusable: 1 day to refuel + 7 days on the moon

expendable: up to 95 days of max EDS/LSAM orbital loither time + 3 days for the earth-moon travel + 7 days on the moon

..."cartridge tanks"...

it's only a possible option

maybe, the simplest way to refuel will be like the air-refuel of military fighters

...Books?

try to dispath four books separately... you will spend four times than send them in a single box...

...tonnes of fuel a year to keep from falling out of the sky...

another foolish claim to support a wrong opinion

...imported Hydrogen from Earth to combine with LOX from the Lunar soil to make suborbital "hops" over the surface for short-term exploration...

a very bad and very very dangerous idea since it multiply 10, 20, 30 times the number of (risky) flights from/to the moon surface!

it needs 10+ years to build the lunar infrastructures

but, when we can send them on the moon, will be BETTER, SAFER and 10+ TIMES CHEAPER to send many vehicles to explore the moon via surface...

it needs only to recharge the batteries of the vehicles, NOT dozens of tons of fuel per "hops"... (that's only sci-fi)

also, with a surface vehicle we can explore the entire space between the moon-base and the new "point", while, with the "hops" we can explore only that "point" and a few miles around it

just a question... why "your" fuel can be stored for months and/or sent at low cost from earth while "my" fuel can't ???

.

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#68 2006-06-07 06:40:52

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,180

Re: Reusable LSAM

RL-10 has been used for years in all the EELVs, many of the Atlas-II/III, and some of the Titan-III/IV rockets. It has a good sucess rate and is probably the most refined small cryogenic engine ever. Since it was intended for upper stages, it is restartable, and was used in the DC-X "hover-rocket" demonstration that sucessfully demonstrated its good throttle control for landing.

Edit: It is rumored that they are good for at least ten firings.

Found simular references to the minimum 10 cycles of restart and saw that it was capable of 4,000 seconds of firing time if one could keep it fueled. It is also rumored that if one throttles back from max output that it would keep firing forever.

Reference for the RL60 which is a replacement engine for the RL10 for both atlas and delta useage.

Pratt to develop new upper stage rocket engine

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#69 2006-06-07 06:59:58

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

Again with the useless flailing, why don't you go back to making pretty rocket pictures gaetano?

First of all, no, a reuseable thing can infact cost the same or even more than an expendable one. This is especially true for rockets, because the vehicle cannot work without large masses of fuel, and importing this fuel costs money. Lots of money: you need a heavy lift rocket (probably a CaLV), an EDS stage, and a dedicated expendable tanker vehicle to deliver enough fuel for only about two flights. The cost of developing this tanker and the cost of developing/building this Lunar space station will easily match the cost of just following the ESAS plan. So yet, we might save money on landers, but orbit-based reuseability incurs other costs in addition, and will wind up costing about the same or more as expendable ones.

Why will the LSAM cost lots more then the CEV will? They are of the same scale, both support similar numbers of astronauts for similar times, both have two stages, both will use common or inexpensive off-the-shelf engines, and construction of vehicles that don't have to withstand reentry is pretty simple. There is no reason for the LSAM to cost far more then CEV will, and you have no qualms with throwing away CEV capsules, so why is saving LSAM so important but CEV is not?

compared with the CEV/SM/LSAM weight, the "superCLV" must lift around 60 mT including its EDS... and there are infinite configurations to build that rocket

Okay, now I just have to say it: you are stupid. There is no other term that fits you... "Infinite configurations?" You are kidding right, just how stupid a thing are you willing to say to prop up your pet plan gaetano? There is no possible way to double the CLV payload without completely abandoning the design. There are NOT an unlimited number of practical configurations, you can't make a CLV that's 200m high, nor one with an 10m wide upper stage, nor one with a seventeen-segment booster. You should know better, because this is just crazy, its probably the most idiotic thing about a launch vehicle you've ever said.

No, each trip to the Moon would require TWO CLVs, and would have to both work and dock within a month of eachother. So, for your plan:

  • Good:
    -You need half a CaLV instead of one
    -You need 1/5th to 1/10th of an LSAM

    Bad:
    -You need half a tanker
    -You need two CLVs per mission
    -You need to develop the Lunar station
    -You need to launch and build the Lunar station
    -You can't burn Hydrogen for your landers or station
    -You need extra development for the reuseable LSAM
    -You need to send tonnes of fuel for the station
    -You still won't have a radiation shelter from Cosmic rays or solar flares
    -You still can't reach the Lunar poles or else you can't launch to/from the station for days at a time
    -You get basically no safety bennefit
    -You are stuck with one LSAM worth of surface payload

the Apollo LM total weight was 4.5 mT of which 2.3 mT was ascent fuel, then, payload:fuel is 1:1 not 1:4

You could at least try to be accurate, two minutes with Google and Astronautix prove that you are either ignorant, lazy, or lying. Or maybe all three... The 1:4 fuel ratio includes the fuel needed to land obviously, while your figure only concerns acent. You have to burn fuel to land the fuel you need to launch off the surface, which adds up too.

And again, long-term loiter with a big fuel tank is different then smaller ones. Little cartridge tanks have more surface area, so they will boil off faster. Simple geometry and all that. Thats why its different. Refueling in zero-gravity is different too, and it is completly unlike filling up on the ground or in jet planes. Since you are planning to do this with cryogenic liquids, you should also know that nobody has ever done that before. Russian vehicle refuel only with hypergolics, which are much easier.

And you are crazy if you think hypothetical Lunar explorers would turn around between surface missions in only one day, thats no where near enough. No, they will need a few days to recuperate and clear/repair their suits & equipment at least.

And yes, a Lunar space station will have to burn tonne quantites of fuel to maintain its orbit aroun dthe Moon. Because the Moon's gravity is weak and inconsistant and the Earth's gravity is so much stronger, there is no really stable orbit around the Moon. Gravity will preturb the orbit and cause objects to slow down and eventually crash. The only way to counteract this is to burn signifigant amounts of rocket fuel, which will have to be imported at huge expense, because the station will be so heavy (perhaps 100MT with landers/capsules easy).

Your idea is broken gaetano, and you can't fix it just like your other ideas. It is beyond the realm of reason for you to continue to support it, so its time for you to be quiet and stop cluttering the board with your ignorance and stupid analogies.
___________________________________________

Now for reuseable suborbital exploration from a surface Lunar base...

So gaetano doesn't like the idea because it enabled multiple flights to/from the surface... but he advertises his orbit-based reuseable exploration because - it enables multiple flights to/from the surface!

And it won't need "ten years" of infrastructure. It will take only three or four CaLV-class cargo flights to deliver equipment for a small LOX plant. One for the nuclear plant or solar arrays, one for the regolith processor/furnace or chemical cell, one for digging equipment, and one for the liquifier. Tank farms could be inflatable plastic bags buried under the soil or under Mylar tents. We could do this in about two years I believe.

but, when we can send them on the moon, will BETTER, SAFER and 10+ times CHEAPER to send many vehicles to explore the moon via surface...

Simple, because we can't drive that far. Driving around  on the Moon will be slow and tricky, since the low gravity and rough terrain would make traversing difficult. And its slow, it could take weeks to drive to the limit of a suborbital hoppers' range, which is too long for safety for life support or from solar flares. A hopper could return quickly (within the LSS capacity of a suit backpack) to the base in this event.

And the distance the hopper can go won't be just a few miles, because of the Moon's weak gravity you could easily go hundreds of kilometers with only a little Hydrogen propellant. Perhaps less then a tonne.

The Hydrogen supply at a hypothetical base would be storable because the ISRU plant will be able to liquify cryogens, of course. Your Lunar space station doesn't, nor does it have a "heat sink" like the Moon does, and couldn't with little cartridge-based tanks.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#70 2006-06-07 07:17:28

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

I see something like this...

-ESAS exploration occurs over a few years with 2-3 missions anually until sites of most interest are visited and a site for a base selected. Possibly near the poles with unlimited sunlight, or maybe on the equator in a major impact crater.

-Flight rate to the Moon increases from 2-3 to 4-5 anually, with one or two of these being crewed flights and the other ~2-4 being pieces for the base. The extra cost of these flights will be mitigated since they will be unmanned cargo. The base components will have been developed after the CaLV/LSAM development was completed and the ISS finally retired some years prior.

-Base is constructed with housing for 4-6 (eight for short times) and the LOX plant/tank farm set up. This would be designed to produce ~90MT of LOX anually (hydrogen too would be nice if ice is found).

-Once a year, a ~15MT load of Hydrogen from Earth would be sent by CaLV/LSAM (if nessesarry) along with some hardware, which could yeild ~100MT of propellant, sufficent for a dozen hops or so depending on distance. At the end of six months, the crew would leave on the full ESAS LSAM they arrived on.

-If cheaper launch vehicles or COTS is available, these would, they would then take over this task, perhaps crew ferrying too.

-If COTS cannot assume crew ferrying, and further cost reductions are desired, then a mini-EDS and a Hydrogen-powerd reuseable LSAM would be developed. Crews or supplies would be sent by two CLV (or comperable) launches to Lunar orbit, and crews/cargos would be ferried to the surface with these reuseable LSAMs.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#71 2006-06-07 10:15:26

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...you go back to making pretty rocket...

if I do that... who will answer to your absurd claims??? (like... "two costs more than twenty" ...or... "10+ times reusable costs more than 100% expendable"... etc.)

...reuseable thing can infact cost the same or even more than an expendable one...

to build it, not to use it!

a "reusable-car" costs a little more than an "expendable-car" (since the first needs an "hole" for resupply, while, the latter has a sealed tank) but, the first car, can be used thousands times with simple refuel, while, the latter, become scrap iron when the gasoline in the tank ends...

if we must do 100 travels with a $30,000 car... they will costs:

$30,000 x 100 = $3,000,000 with 100 "expendable-cars", or...

$30,000 + $5,000 of fuel = $35,000 with a "reusable-car"

also if we must pay $10,000 the fuel for each travel, the total cost never reach $3,000,000 but only:

$10,000 x 100 = $1,000,000 + $30,000 = $1,030,000 ...about $2,000,000 SAVED !!!

...especially true for rockets...

the LSAM is not (simply) a "rocket"... like with the CEV/SM, the LSAM "rocket" may cost 10% of its full price and its fuel only 0.1%... 90% of its cost will be its pressurized vehicle, life support, electronices, navigations systems, tools. exploration hardware, lunar-SUV, etc.

a rocket CAN be expendable because 99% of its mass and 90% of its costs are tanks, fuel and low cost engines

...importing this fuel costs money...

right, it costs money... exactly it costs 1/4 pf the money to import EVERY TIME (both) the fuel and a new vehicle

it's simple to understand for 99.99999% of peoples, only your mind (...or your company...???) rejects that simple truth!

...you need a heavy lift rocket (probably a CaLV), an EDS stage...

the CaLV and the EDS will be built soon... where is the problem?

...about two flights...

I think will be three or more, but, also with "your" figure, we save NINE LSAMs and FIVE CaLVs every TEN landings/missions!!!

...cost of developing this tanker...

"develop a tank" may costs like... "develop a tank"... nothing more

...developing/building this Lunar space station...

develop an orbital module may cost near zero, since 99% of the R&D was already done in last 30 years with the ISS, Mir, Shuttle labs, etc.

build it will costs a reasonable amount of money

but, if you don't like the LSS, the reusable-LSAM may (simply) refueled in lunar orbit with a big tank sent from earth (without any LSS)

...Why will the LSAM cost lots more then the CEV will?...

no, the LSAM will not costs "lots" more a CEV since BOTH will have a very high (REAL) price (especially at the "adjusted" 2020 costs...)

but (probably) you think that develop, test, build and launch two new and very complex vehicles like the CEV and LSAM can't costs $3B like add the "5th segment" to an SRB"...

...you have no qualms with throwing away CEV capsules...

the CEV burns in the atmosphere at very high temperature, then, only a few internal parts (electronics?) may be reusable

the LSAM don't burns in the (unexisting) lunar atmosphere and will be PERFECT after each flight, then, reusable

...no possible way to double the CLV payload without completely abandoning the design...

"superCLV" is only a name... it means "a 60 mT payload rockets"... no need to build it like the CLV, then, we have "INFINITE" configurations of rockets/engines/fuel to design it (and it don't need to be 200m nor 17-seg.SRB nor 10m large... like your foolish claims)

...each trip to the Moon would require TWO CLVs...

no, only a better CLV (or a similar rocket)

Bad:
-You need half a tanker
-You need two CLVs per mission
-You need to develop the Lunar station
-You need to launch and build the Lunar station
-You can't burn Hydrogen for your landers or station
-You need extra development for the reuseable LSAM
-You need to send tonnes of fuel for the station
-You still won't have a radiation shelter from Cosmic rays or solar flares
-You still can't reach the Lunar poles or else you can't launch to/from the station for days at a time
-You get basically no safety bennefit
-You are stuck with one LSAM worth of surface payload

I don't know if you say the same in America, but, in Italy, we call it "Ufficio Complicazione Problemi Semplici" that, translated, may sounds like "Office to Complicate Simple Problems" (an you can be the "ad-honorem chief" of that office...)

orbital/surface earth/ISRU "refueling" will be the "key-technology" of ALL future (moon, mars and beyond) travels

if we don't/can't develop and build (NOW) that technology we will never go NOWHERE !!!

...two minutes with Google and Astronautix...

it is exatly the source I've used

the reusable-LSAM will have the same tanks of the expendable-LSAM (since the first time it come form earth must have the LOI braking fuel) then its tanks' volume will exceeds the specs we need to landings/departures with (all, less or more) the LSAM-tools' weight, WITHOUT any "extra-tanks"

...long-term loiter with a big fuel tank is different then smaller ones...

again... 40-50 days (with four landings/refuels) will be only HALF the (planned) max earth orbit (up to 95 days) loither time of the big EDS thanks AND the little LSAM tanks

...cartridge tanks have more surface area...

true, but they may be simpler to change

however, the fighter-like refuel may be more weight/volume efficient

...in zero-gravity is different too...

it can't be more complex than thousands other (very complex) problems (solved in last 40 years) to fly in the space

...with hypergolics, which are much easier...

since the LSAM don't exist now (not even on the engineers' paper!) it don't need to use LOX/LH2 but the best, easy to use, easy to refuel, easy to store propellants

...they will need a few days to recuperate and clear/repair their suits & equipment at least...

with a 40-50 days' missions, a crew will have the time to land four times, stay four weeks on lunar surface and have a (about) a week between each landing

...will have to burn tonne quantites of fuel to maintain its orbit aroun the Moon...

probably in its full (20+ years) life, not every year

it can't need more fuel than reboost the ISS that is 10 times the weight and runs around the earth with six times the gravity

only... foolish claims to support a wrong opinion

...gravity will preturb the orbit and cause objects to slow down and eventually crash...

then... we can't send nothing around the moon (since ALL objects have a mass and can crash...) and we must stop the ESAS plan now...

...so its time for you to be quiet and stop cluttering the board...

you can give dictates only to your dog (if you have a dog... and if it, still, live with you...)

...but he advertises his orbit-based reuseable exploration...

no, it is only the most efficient way to explore the moon in the first 15+ years while building the infrastructures (vehicles, energy, etc.) for an efficient surface exploration (that will be better, safer and cheaper)

...three or four CaLV-class cargo flights to deliver equipment for a small LOX plant...

but only for a slow exploration of a little part of the moon

a SINGLE (good) pressurized-rover will needs a CaLV launch... and dozens of them must be sent for a true exploration

...Driving around on the Moon will be slow...

but SAFE

we have explored the earth surface with thousands scientists in hundreds years... we can't explore the moon in a few years... you need to have patience

further LSAM landings will be used only to establish new moon-bases

"hoppers" can be used only for emergency flights (like sun flares, etc.)

...flight rate to the Moon increases from 2-3 to 4-5 anually...

with expendable-only vehicles double the missions needs twice the funds (good luck to NASA when it ask the government for an extra $100 billion...)

with reusable-LSAMs and the LSS we can have 10+ moon landings/missions PER YEAR from the FIRST YEAR and with the SAME FUNDS

do you want MORE (BETTER and FASTER) moon exploration or MORE expendable vehicles to build (/sell...) ???

~90MT of LOX anually... hydrogen too would be nice if ice is found...

good dreams to do with the real VSE funds...

...would leave on the full ESAS LSAM they arrived on... mini-EDS and a Hydrogen-powerd reuseable LSAM would be developed...

why "your" LSAM can be "reusable" a dozen times while "my" LSAM can't?

.

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#72 2006-06-07 11:10:44

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,180

Re: Reusable LSAM

...you need a heavy lift rocket (probably a CaLV), an EDS stage...

the CaLV and the EDS will be built soon... where is the problem?

How soon do you think? not,,, The building of the CaLV will not happen until sometime after 2012.. and will not get used for moon exploration until 2018 at the earliest.

...you have no qualms with throwing away CEV capsules...

the CEV burns in the atmosphere at very high temperature, then, only a few internal parts (electronics?) may be reusable


You really do not understand the purpose of a heatshield and the landing techniques that will be employed to allow for the Capsule to be reused...


...with hypergolics, which are much easier...

since the LSAM don't exist now (not even on the engineers' paper!) it don't need to use LOX/LH2 but the best, easy to use, easy to refuel, easy to store propellants

You are right that the LSAM does not exist as of yet and is only on paper. That is where the choices come in to play for how to design for the best cost per application design considerations.

Yes hypergolic fuels are easier to store and use but there is the drawback of the corrosion that they do cause on the tanks that they would be in. LOX/LH2 is harder to store for long periods because of boiloff but it will make for a rocket from the bottom up that uses all the same fuels a more realistic design.

...three or four CaLV-class cargo flights to deliver equipment for a small LOX plant...

but only for a slow exploration of a little part of the moon

Thats where the funding levels would need to change if the desire is for a quicker exploration utilizing more rockets. For now we will be getting 2 complete flights per year once the moon missions begin.


"hoppers" can be used only for emergency flights (like sun flares, etc.)

This concept can be used anytime but keep in mind that you must reprocess the lunar insitu resources in order to refuel the LSAM for any further flights.

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#73 2006-06-07 11:38:59

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

How soon do you think?

in time to launch the moon-hardware, before that it's unnecessary (and unexisting)

You really do not understand the purpose of a heatshield and the landing techniques

please search on Google an image of a burned Apollo to know if it can be (safely) refurbished

...is where the choices come in to play for how to design for the best cost per application design considerations...

then, it can be designed little, big, reusable, expendable, with LOX/LH2, with hypergolic, etc. etc. etc.

...getting 2 complete flights per year once the moon missions begin...

the first two CaLV flights may be sufficient to send one LSS module and the first Crew Habitat... and the FIRST year can have up to FIVE landings/missions (NOT ONLY TWO) with one CEV, one reusable-LSAM, one CLV and two CaLV (the first to send the CEV/LSAM and the second to send the refuel to accomplish four more missions) with the SAME FUNDS

...lunar insitu resources in order to refuel the LSAM for any further flights...

sorry for the optimists... but I don't see any realistic and usable lunar ISRU before 10+ years of missions/exploration

.

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#74 2006-06-07 19:33:01

GCNRevenger
Member
From: Earth
Registered: 2003-10-14
Posts: 6,056

Re: Reusable LSAM

Your whining and flailing gaetano is rapidly approaching the threshold of senselessness, which has no place here. If you aren't going to be serious about what you write, which it looks less and less so, then you shouldn't write here.

And yes to develop, build, and operate reuseable Lunar landers very well will cost about the same as expendable ones so long as all the propellant is imported from Earth, and could even cost more. The superior LSAM will require more development, the tanker will require development, and the tankers will have to be expendable too. Plus, your plan calls for the development of a brand new man rated medium-heavy rocket in the 60MT payload range, which will itself cost several billion most likely. And then there is the new "super CEV service module." Weren't you whining about how awful it was to develop two new rockets instead of one?

I'm not going to lower the conversation to trying to explain to why you are wrong in terms of your analogy, because it is so patently stupid: if anything, cars are the perfect archtype of a reuseable vehicle with an inexpensive fuel supply. Rockets are the exact opposit, despite the fuel itself being inexpensive to produce transporting it is not. This too is just as much an expense of the fuel as making it in the first place, and bringing more fuel from Earth is about as expensive as simply bringing a brand new vehicle. The rocket to launch that fuel and push it to the Moon plus the vehicle (and station?) to perform the docking and transfer costs aproximatly the same as simply putting a new vehicle on that rocket.

develop a tank" may costs like... "develop a tank"... nothing more

And really gaetano, if you are going to try to read and write in english on an english message board, you have to do better then this (can't identify hyperbole either). A tanker is a vehicle, a vehicle for carrying fluids, which you will have to develop, build, fly, and throw away to carry your fuel from the CaLV to your LSAMs.

This vehicle will need power for up to 2-3 weeks (to match orbit with LSAMs in polar orbit), so it can't have batteries. It will need maneuvering thrusters, attitude sensors, and an engine for LOI. It will need high accuracy and precision automation for docking. It will cost, if you include development, about the same per-unit as an unmanned LSAM. After all, it will do much the same thing, except it has to have automated docking capabilities whereas the "expendable" cargo LSAM won't. So now instead of needing 1/5 to 1/10 of an LSAM for every mission, now you need 4/5 or 6/10.

develop an orbital module may cost near zero, since 99% of the R&D was already done in last 30 years with the ISS, Mir

No. The US has never developed a station module with maneuvering engines or the longevity to operate for many years in Lunar orbit. The Russians have, but unless they are going to build your station, then you are stuck. Plus, this station must resist large doses of radiation, which will make it quite heavy, and will also require regular refuelings to correct for an unstable Lunar orbit (especially with heavy shielding).

no, the LSAM will not costs "lots" more a CEV since BOTH will have a very high (REAL) price

Then your plan is even worse, since if development costs will spiral and bloat like the Shuttle era, then your much more reliable reuseable LSAM will cost much more to develop. How many expendable LSAMs will this buy? Quite a few I bet.

I want to re-emphasize that a rocket in the 60MT range will not be cheap nor easy to develop. It will not in any way be an extension of any exsisting rocket, because there is no similar rocket. It will have to either be a cluster of smaller rockets like the five-core Delta-IV or a tripple-core Falcon-IX, or else it will have to be a brand new rocket. This rocket will cost alot of money to develop, the boosters for the EELVs are too small and the CLV/CaLV too large, nor is it likely to have engine-out. And it will have to be man-rated to boot.

orbital/surface earth/ISRU "refueling" will be the "key-technology" of ALL future (moon, mars and beyond) travels

if we don't/can't develop and build (NOW) that technology we will never go NOWHERE !!!

Orbital and surface refueling are seperate technologies, with the latter is easier since you have gravity and fuel hoses are easy to handle. Orbital refueling is much trickier, since you have to consider fuel settling and such, and is completly different. And no, no we don't have to develop orbital refueling, there is no reason to. We don't need it for the Moon nor do we need it for early Mars missions like DRM-III.

since the LSAM don't exist now (not even on the engineers' paper!) it don't need to use LOX/LH2 but the best, easy to use, easy to refuel, easy to store propellants... it can be designed little, big, reusable, expendable, with LOX/LH2, with hypergolic, etc. etc. etc

Now you are just flailing. The choice of propellant is extremely important, and directly determines if your plan is workable, good or bad. Because the fuel used for your plan is so important, you absolutely have to choose before anybody (including you) can decide. I assume you will be burning Methane, since it has okay performance and a six-month storage life. The most important measure of propellant efficiency is its specific impulse (Isp), with Methane being around 365sec and Hydrogen around 450sec. But the effective Isp for Hydrogen, if you mix it with Lunar oxygen, is somewhere around 2000sec. Wins hands down.

...two minutes with Google and Astronautix...

it is exatly the source I've used

Then this is proof that you don't know anything; if you actually read the article, you would have known that the LEM's decent module carried over eight tonnes of fuel, and the combined mass of acent stage fueled and the decent stage unfueled was ~6MT. That means that for every tonne launched into Lunar orbit, you need about three tonnes of fuel for the round trip from orbit.

probably in its full (20+ years) life, not every year... it can't need more fuel than reboost the ISS that is 10 times the weight and runs around the earth with six times the gravity... only foolish claims to support a wrong opinion

Absolutely it can. You are talking a station with between 50-100MT of mass that will need signifigant orbital adjustment on a regular basis. The ISS I am sure needs less fuel because its orbit is stable and only degraded by atmospheric drag of the extreme upper atmosphere. Its not a wrong opinion, and its true, stable orbits rely on relativly strong gravity which the Moon doesn't have versus the Earth. The solution is just to not orbit anything heavy for any long length of time, which a surface-centric Lunar program does but yours doesn't.

no, it is only the most efficient way to explore the moon in the first 15+ years while building the infrastructures (vehicles, energy, etc.) for an efficient surface exploration (that will be better, safer and cheaper)

You have been told why this is not what you say it is, so if you can't defend it you should say so and be quiet, otherwise all you are doing is advertising your ugly website instead of discussing anything. And this is a discussion thread and is not for advertising.

but only for a slow exploration of a little part of the moon... a SINGLE (good) pressurized-rover will needs a CaLV launch... and dozens of them must be sent for a true exploration

And a single load of Hydrogen would permit a dozen or more hops. And, since these are suborbital and the Moon's gravity is weak, they can go long (several hundred kilometers at least) distances, and it can go to sites of interest directly in a short amount of time. You could even deliver the Hydrogen on this suborbital lander... A rover on the Moon will be so slow, that reguardless of its range, the crew simply can't stay in the rover very long without the risk of a lethal solar flare. This limits its range to much less then a suborbital "hop." And thats if you don't accidently drive over a lava tube or something.

we have explored the earth surface with thousands scientists in hundreds years... we can't explore the moon in a few years... you need to have patience

Well thats stupid, if we aren't making good progress per-year, then the total cost of the science will be huge. The public will rightfully demand more productivity for their money. Weren't you whining about the public becoming uninterested with scientists poking around the Moon?

with expendable-only vehicles double the missions needs twice the funds... good dreams to do with the real VSE funds

Your supposition about the costs, which are faulty. And why can't NASA build a Moon base? They are going to have $16.5Bn a year after all, which adds up over ~15 years.

why "your" LSAM can be "reusable" a dozen times while "my" LSAM can't? ...sorry for the optimists... but I don't see any realistic and usable lunar ISRU before 10+ years of missions/exploration

Because your reuseable LSAM makes no sense. It doesn't save that much money, while mine does, because it uses so little imported fuel. Especially since its Hydrogen powerd. And why will a Lunar ISRU plant take that long? A plant big enough to make half that much fuel on Mars, including the nuclear reactor, been estimated to weigh in the 20MT region. I think such a plant can be built on the Moon around 100MT. This would take four or five flights of the CaLV, which is only a year's worth at Shuttle-like launch rates.

Oh, and I almost forgot:

image of a burned Apollo to know if it can be (safely) refurbished

Apollo looked all burned up because its supposed to, the heat shield was ablative, it keeps the capsule cool by intentionally burning off. It just looks really awful since some of its smoke stuck to the side of the capsule.


"The power of accurate observation is often called cynicism by those that do not have it." - George Bernard Shaw

The glass is at 50% of capacity

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#75 2006-06-08 03:13:15

gaetanomarano
Member
From: Italy
Registered: 2006-05-06
Posts: 701

Re: Reusable LSAM

...operate reuseable Lunar landers very well will cost about the same as expendable ones so long as all the propellant is imported from Earth...

I think that we need only to wait a few months (or, max, two years) while NASA will change (again...) its "final" ESAS plan about the LSAM from "expendable" to "reusable" (with or without the LSS) to save over $20 billions of CaLVs and LSAMs in the first 20 moon missions

and NASA already knows the "right way"... www.newscientistspace.com/article/dn925 … ation.html

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