Author Topic: Impact of lunar ice on Exploration Architecture  (Read 212544 times)

Offline Danderman

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Impact of lunar ice on Exploration Architecture
« on: 11/16/2009 04:46 pm »
My belief is that the discovery of lunar ice obviates virtually everything done so far in the Exploration program, assuming the following:

Cost is the prime barrier to exploration;

Lunar water ice could be processed by humans on the lunar surface, assuming that equipment with a mass of the single digit tons could be relatively easily operated on the lunar surface for the purpose of converting lunar water into LOX/LH2 propellant;

The prime driver for the Exploration program is not jobs, but Exploration.

These may not be reasonable assumptions, but if they are indeed valid, then we could have a robust near term Exploration program, based on more or less current technologies (ie Delta IV with S-IVB class upper stage + some sort of Centaur class escape stage). This would allow humans to return to the Moon much sooner than currently planned, at much lower cost.




Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #1 on: 11/17/2009 12:38 am »
Let me explain further - if the near term objective is the creation of a self sustained local orbital capability on the moon, ie a vehicle that could land on the surface with empty propellant tanks, be refueled on the surface, and then attain lunar orbit and subsequent descent back to a propellant base, then we could probably attain that objective using payloads sent to the moon with a mass of less than 13 tons per payload, using current technologies, at much lower cost than the Exploration program plans.

Ironically, the Ares I-X launcher may be practical under such an architecture.
« Last Edit: 11/17/2009 08:58 pm by Danderman »

Offline MickQ

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Re: Impact of lunar ice on Exploration Architecture
« Reply #2 on: 11/17/2009 12:44 am »
Let me explain further - if the near term objective is the creation of a self sustain local orbital capability on the moon, ie a vehicle that could land on the surface with empty propellant tanks, be refueled on the surface, and then attain lunar orbit and subsequent descent back to a propellant base, then we could probably attain that objective using payloads sent to the moon with a mass of less than 13 tons per payload, using current technologies, at much lower cost than the Exploration program plans.

Ironically, the Ares I-X launcher may be practical under such an architecture.


Just how much ice would need to be processed to supply the propellant needed for one  round trip ?

Mick.

Offline kkattula

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Re: Impact of lunar ice on Exploration Architecture
« Reply #3 on: 11/17/2009 06:53 am »
Let me explain further - if the near term objective is the creation of a self sustain local orbital capability on the moon, ie a vehicle that could land on the surface with empty propellant tanks, be refueled on the surface, and then attain lunar orbit and subsequent descent back to a propellant base, then we could probably attain that objective using payloads sent to the moon with a mass of less than 13 tons per payload, using current technologies, at much lower cost than the Exploration program plans.

Ironically, the Ares I-X launcher may be practical under such an architecture.


Just how much ice would need to be processed to supply the propellant needed for one  round trip ?

Mick.

Lunar orbits are not very stable, so EML-1 or EML-2 would be more practical places to put depots. Assuming:

1) The same mass of payload is transported in each direction e.g. extra fuel or water to the depot, and supplies/people to the Moon.

2) An RL-10 derived engine with 460 Isp.

3) Vehicle dry mass is equivalent to cargo mass.

Then you need about 4 tons of water (converted into LOX & LH2) for every 1 ton of round-trip cargo capacity.

Might be better to have dedicated tankers that carry fuel or water to the depot and return empty. and dedicated cargo landers that return to the depot with excess fuel in their tanks, so just need topping up.

Edit: So if you want to move 200 tons per year from L2 to the Moon, and put 200 tons of fuel and/or water in an L2 depot, all using lunar ISRU propellant, you need to extract a little under 3 tons of water per day.

Assuming the icey regolith water content is 1%, that means processing almost 300 tons of regolith per day. But it may be as high as 4%.
« Last Edit: 11/17/2009 07:01 am by kkattula »

Offline jacksson

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Re: Impact of lunar ice on Exploration Architecture
« Reply #4 on: 11/17/2009 08:04 am »
Interesting read on Lunar Ice and Nuclear Steam rocket by a Dr. Anthony Zuppero. Link is from The Register.

http://www.theregister.co.uk/2009/11/15/zuppero_solar_system/

Dr. Zupperos web site is here:

http://www.neofuel.com/

enjoy the read....


Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #5 on: 11/17/2009 08:54 pm »
Just how much ice would need to be processed to supply the propellant needed for one  round trip ?

I don't know.

What I do know is that by landing a LH2 fueled robotic lander with empty prop tanks, the storage of LOX and LH2 would be relatively easy, as it could be stored in the lander tanks.

The question of how much lunar regolith or just chunks of ice have to be processed to fill the tanks is a big question.  For example, could a crew of 2 land in a "Scout class" lander, and over a couple of days fill the prop tanks of the robot lander?

Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #6 on: 11/17/2009 08:57 pm »
Assuming the icey regolith water content is 1%, that means processing almost 300 tons of regolith per day. But it may be as high as 4%.

Once again, the above comment ignores the Clementine and Lunar Prospector data. Clementine discovered large area with a reflective equivalent of water ice; Prospector found vast amounts of hydrogen in the same general area. Just because NASA claimed to find on 24 kg of water in the plume does not mean that there aren't sheets of ice in that crater. The mechanism of transporting water in an impact plume is not well known.

Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #7 on: 11/17/2009 09:06 pm »
It looks like what I am proposing here is a (Double) Lunar Orbit Rendezvous architecture for lunar ISRU missions - a lander launched separately from the crew capsule - each with a post-LEO mass of about 13 tons; the 2 craft would rendezvous in lunar orbit, where the crew would enter the lander. As a proof of concept, a 13 tons mass could be sent to the Moon by something like Ariane V with a LH2 upper stage; Delta IV with something like an S-IVB upper stage plus heavy Centaur; or even Proton with a LH2 upper stage(s).  I assume that a 30 mt payload to LEO that includes a LH2 stage gets 13 mt towards the Moon, and that around 30% of that mass must be prop for the crew capsule to get into and out of lunar orbit.

The basic elements of the architecture are the 13 ton crew capsule, the 13 ton crew lander, and a 13 ton robotic lander that uses Lh2 for prop.

This architecture would cost a fraction of the current architecture, but would have an economic driver - the generation of loads of LH2 and LOX on the lunar surface.

Assuming that the crew capsule was Soyuz with an enlarged prop section (sort of a revised Soyuz-LOK, and the Scout lander was something like the Soviet LK, with a more robust descent stage and an enlarged crew cabin (thus increasing its mass from 5.5 mt to 13 mt), the long pole in the tent would be the development of the robotic lander, and the launch vehicle (although LV development would be trivial compared with Ares).


Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #8 on: 11/17/2009 09:10 pm »
So if you want to move 200 tons per year from L2 to the Moon, and put 200 tons of fuel and/or water in an L2 depot, all using lunar ISRU propellant, you need to extract a little under 3 tons of water per day.

I don't. The goal is to fill the prop tanks of the LH2 lander, so that it could get off the lunar surface, and get into a lunar orbit to receive supplies from the Earth, and then land again. Once that basic capability is achieved, lunar landings of humans would become commonplace, and the fun would begin.

How much prop is required? The filled mass of the robotic lander would be about 12 tons or so, after insertion into lunar orbit. Maybe half of that mass would be the prop required to get from the surface to orbit and then back again. So, the question is whether a crew of two could generate 6 tons of prop and LOX in a relatively short period of time, using a magic machine that converts icy regolith into prop and pumps it into the prop tanks.


Offline kkattula

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Re: Impact of lunar ice on Exploration Architecture
« Reply #9 on: 11/18/2009 04:57 am »
Your magic machine, (which wouldn't be magic, just a matter of engineering), would have considerable mass, as would the equipment to gather the regolith (or even relatively pure ice).

Up to a certain number of missions, it would be more mass efficient to pre-land expendable tankers with the propellant to refuel the lander. Above that number it would be more efficient to send the ISRU equipment and make the propellant.

You'll actually need more than half of the 12 tons on the surface to be fuel.  Without picking up any cargo in lunar orbit, and without any landing reserve, it would need to be almost 7 out of 12 tons.

Assuming the supplies picked up in lunar orbit are equal in mass to the empty lander, approximately 2/3 of the launch mass from the surface would have to be fuel. So starting on the Moon with 4 tons of empty lander & 8 tons of fuel, lands 4 tons of cargo.



Offline kkattula

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Re: Impact of lunar ice on Exploration Architecture
« Reply #10 on: 11/18/2009 05:26 am »
Assuming the icey regolith water content is 1%, that means processing almost 300 tons of regolith per day. But it may be as high as 4%.

Once again, the above comment ignores the Clementine and Lunar Prospector data. Clementine discovered large area with a reflective equivalent of water ice; Prospector found vast amounts of hydrogen in the same general area. Just because NASA claimed to find on 24 kg of water in the plume does not mean that there aren't sheets of ice in that crater. The mechanism of transporting water in an impact plume is not well known.


The interpretation of Clementine's radar data is still open to question. Arecibo found similar relections in non shadowed areas. Prospector couldn't determine concentration.

There may be ice sheets, there may not be. A worst case of 1% is not too bad. Plan for the worst and hope to be pleasantly surprised.

I heard NASA estimate 100kg of water just in their field of view of the plume.  That's encouraging for a 20m crater.

Offline Bill White

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Re: Impact of lunar ice on Exploration Architecture
« Reply #11 on: 11/18/2009 02:50 pm »
I was fortunate enough to spend a day and a half at the ongoing LEAG conference. Unfortunately, I had to leave early.

In any event, the Lunar Reconnaissance Orbiter is returning marvelous data from the lunar South Pole (beyond LCROSS) -- data which has only begun to be analyzed.

Preliminary Diviner data suggests the South Pole is colder than previously believed and blending that data with Russian LEND neutron sensor data suggests that water ice might exist OUTSIDE permanently shaded areas but buried by regolith. The Russian presenter suggested areas with water ice as high as ~2% or even ~3%

Some indications were against the existence of sheets of pure ice lying in the open in those shaded regions. More ice outside the craters but mixed with or covered by regolith.

Laser altimeter scans suggests there are far more flat areas capable of allowing landing than may have been believed. Better resolution from the instruments seems to be the reason.
 
Going forward? The LRO data shall continue to be collected and needs to be analyzed and robotic precursors need to be sent to gather even more data so we can design surface operations architectures capable of extracting that ice. Without robot precursors sent to the South Pole, planning actual human missions or actual mining operations would seem wildly premature.

Now we come to geo-politics.

If there is abundant water ice that shall significantly lower the cost of cis-lunar and beyond cis-lunar space exploration there is no way in heck the rest of the world will let the United States acquire a monopoly over those resources. We simply lack the terrestrial geo-political firepower to acquire and enforce such a monopoly.

Therefore, we also need a global geo-political strategy for dealing with that ice.

But for now, getting good mobile robots onto the lunar South Pole would seem to be Job #1. At least IMHO.

= = =

Also, the colder temperatures could allow for ammonia ice to be preserved at the lunar South Pole. And finding a big ball of ammonia ice would be very interesting.
EML architectures should be seen as ratchet opportunities

Offline Archibald

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Re: Impact of lunar ice on Exploration Architecture
« Reply #12 on: 11/18/2009 04:09 pm »
Quote

Also, the colder temperatures could allow for ammonia ice to be preserved at the lunar South Pole. And finding a big ball of ammonia ice would be very interesting.


Yes !

Fill a L2 depot with lunar ammonia and LOX. Then, explore the moon with an LOX/ NH3 lander refuelled from this depot.

If you want to expend the architecture beyond the moon, the EML-2 ammonia depot is a bonanza.
Indeed ammonia flexibility as propellant allow you to chose between many space propulsion systems.

Check the list below and chose your space propulsion system. Then, explore !

Ammonia and NTO
Hypergolics. Easy to store, low-cost, low performance. Specific impulse: 320 seconds.

Ammonia and Lunox
Better performance. Already in use for the lunar lander. Reuse the lander engines for a chemical Mars ship. Performance match kerosene, and even methane – 350 seconds.  Mars Direct can be done with ammonia instead of methane.

Ammonia and NTR
Lower performance than LH2, that’s true. ISP = 600 seconds.
But you don’t need Borowski magic bi- or tri- modal engines. Unlike LH2, ammonia doesn’t boil off. It is eight times denser than LH2.

Ammonia and arcjets
First step into electric propulsion. Specific impulse is modest – 1050 seconds at best. However ammonia arcjets are proven technology, thanks to the ESEX experiment.

Ammonia and high-performance electric propulsion.
Hall and Ion thrusters can’t use NH3. However they are no longer the only game in town. VASIMR can certainly works with ammonia. If it doesn’t, other advanced electric thrusters can. LiLfa, MPD, PIT thrusters works with NH3.

Only hydrazine and LH2 offer such versatility. But hydrazine is toxic and hard to ISRU, while LH2 is hard to store over long periods of time.
« Last Edit: 11/18/2009 04:12 pm by Archibald »
Han shot first and Gwynne Shotwell !

Offline robertross

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Re: Impact of lunar ice on Exploration Architecture
« Reply #13 on: 11/18/2009 04:19 pm »
I was fortunate enough to spend a day and a half at the ongoing LEAG conference. Unfortunately, I had to leave early.

In any event, the Lunar Reconnaissance Orbiter is returning marvelous data from the lunar South Pole (beyond LCROSS) -- data which has only begun to be analyzed.

...

But for now, getting good mobile robots onto the lunar South Pole would seem to be Job #1. At least IMHO.

= = =

Also, the colder temperatures could allow for ammonia ice to be preserved at the lunar South Pole. And finding a big ball of ammonia ice would be very interesting.

Thanks for passing that information along Bill.

Very good news indeed.

Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #14 on: 11/18/2009 04:39 pm »
Your magic machine, (which wouldn't be magic, just a matter of engineering), would have considerable mass, as would the equipment to gather the regolith (or even relatively pure ice).

Up to a certain number of missions, it would be more mass efficient to pre-land expendable tankers with the propellant to refuel the lander. Above that number it would be more efficient to send the ISRU equipment and make the propellant.

You'll actually need more than half of the 12 tons on the surface to be fuel.  Without picking up any cargo in lunar orbit, and without any landing reserve, it would need to be almost 7 out of 12 tons.

Assuming the supplies picked up in lunar orbit are equal in mass to the empty lander, approximately 2/3 of the launch mass from the surface would have to be fuel. So starting on the Moon with 4 tons of empty lander & 8 tons of fuel, lands 4 tons of cargo.

Concerning the "magic" propellant making machine, I calling it "magic" for now, since I am simply handwaving it. However, the critical point is that the machine obviates the need for Ares V class launch vehicles, so the question is whether the cost of development and manufacture of such a machine would be less than the cost of development and manufacture of Ares V (or whatever big booster would be required for the current architecture).

As for the prop mass for the robotic lander, remember that the concept is to use LH2 for prop, so the prop numbers above are not correct. As an example, the Apollo LM had a mass ratio of 50%, using storable propellants, and it landed and achieved lunar orbit.

The mass of the magic machine is TBD, but it could be carried as payload in a lander, perhaps with a mass of 1 ton, or in pieces of 1 ton apiece.

Finally, the architecture calls for expendable landers in the initial stages. However, even in the early stages, LH2 propelled landers could also be used as expendable cargo carriers. In this case, the available cargo carried by a one way LH2 lander would be significantly more than 1 ton. Let's say, its a 2 ton payload - could a machine that takes in icy regolith and produces LH2/LOX have a mass of < 2 tons (assuming nuke power)? I don't know.

Offline Danderman

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Re: Impact of lunar ice on Exploration Architecture
« Reply #15 on: 11/18/2009 04:40 pm »
Discussion of prop depots in space is off topic for this thread, for now. Please post comments on prop depots somewhere else.

Offline Bill White

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Re: Impact of lunar ice on Exploration Architecture
« Reply #16 on: 11/18/2009 05:00 pm »
IMHO, the existence of lunar ice in sufficient quantities to support commercially viable enterprises renders the current NASA-centric exploration architecture obsolete.

Q: Impact of lunar ice on Exploration Architecture?

A: Shattered paradigms and a need to return to the drawing board both in terms of mission architecture and the geo-political implications of same.
EML architectures should be seen as ratchet opportunities

Offline Downix

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Re: Impact of lunar ice on Exploration Architecture
« Reply #17 on: 11/18/2009 05:10 pm »
The japanese pay huge money for imported ice with special properties.  It would, indeed, be a luxury for some ultra-expensive product to be made using lunar ice....
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Offline robertross

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Re: Impact of lunar ice on Exploration Architecture
« Reply #18 on: 11/18/2009 05:50 pm »
The japanese pay huge money for imported ice with special properties.  It would, indeed, be a luxury for some ultra-expensive product to be made using lunar ice....

Some of those examples include Evian-lunar & Moonbucks...posts I had seen on a CBC blog.

Offline Robotbeat

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Re: Impact of lunar ice on Exploration Architecture
« Reply #19 on: 11/18/2009 07:51 pm »
The japanese pay huge money for imported ice with special properties.  It would, indeed, be a luxury for some ultra-expensive product to be made using lunar ice....

Some of those examples include Evian-lunar & Moonbucks...posts I had seen on a CBC blog.
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