Author Topic: Dual-Moonbase Architecture  (Read 16468 times)

Offline redliox

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Dual-Moonbase Architecture
« on: 03/18/2014 10:42 pm »
Thought a little bit over how a Lunar Program could be gradually built up, utilizing items often cited as "essential" such as the Lagrange points, ISRU, propellant depots, and even polar ice.  Trick of course is putting this in a pill Congress can swallow and keeping it overall simple.  What I lay out here would be a scheme akin to "Lunar Direct" that was a spinoff of "Mars Direct", but incorporating fuel depots and polar exploration in 3 phases, each with a differing yet complementary set of priorities that ends up with 2 useable bases and a propellant depot.

Phase I - "Oceanus"
Focusing on a straightforward return to the moon; "Oceanus" implies Oceanus Procellarum, as the initial site would be towards the lunar limb, whether it be the western or eastern.  The initial and majority of the flights are cargo, delivering a habitat, a telescope and geologic gear, 5 "utility" robotic rovers (think MERs with snowplows and on steroids), 3 crew rovers (think updated Apollo rover), and twin sets of ISRU modules that would gradually produce "building blocks" and LOX from regolith dug up by the utility rovers.  The crewed visits would range from a week to a full lunar day as the base components arrive, with their main purpose activating the outpost and local recon.  All flights would be direct, any rendezvous strictly in LEO, and if reuseable the crewed vehicles using aerocapture to return to LEO at mission's end.

Phase II - "Aquarius"
Propellants begin to become the focus, as does utilizing cislunar space.  Only 2 cargo flights are sent, the first being a self-contained LOX depot that's basically a flying H2 tank from SLS sent to wait at a LaGrange point.  The more numerous crew flights initially are fully fueled, but first begin hauling LOX on the return trip, and then using the depot for LOX both inbound and outbound.  While most flights revisit the equatorial limb base (ELB), 2 flights investigate other sites; one would be a "random" yet science-influenced site such as Copernicus or Aristarchus, while the second would be a polar region reasonably close to ice, such as Shackleton  or Peary.  The second cargo flight descends, delivering a habitat and rovers.

Phase III - "Frigoris"
With a habitat established at a pole, cargo flights descend to fully establish a smaller but water-focused Polar Base (PB).  As water is tentatively harvested at PB, back at ELB a new cargo flight delivers equipment to upgrade the base and maximize LOX production.  All crewed flights from the ELB stopover at the LOX Depot, refueling themselves but also restocking the supply before returning to LEO.  By the end 2 regions on the Moon are thoroughly explored, 2 differing sources of LOX are extracted, and the seeds are planted for self-sufficiency.

I will later add more to this thread, explaining the specifics of landers, ect.  For now this is a would-be architecture for a glance-over.
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Offline gbaikie

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Re: Dual-Moonbase Architecture
« Reply #1 on: 03/18/2014 11:59 pm »
Thought a little bit over how a Lunar Program could be gradually built up, utilizing items often cited as "essential" such as the Lagrange points, ISRU, propellant depots, and even polar ice.  Trick of course is putting this in a pill Congress can swallow and keeping it overall simple.  What I lay out here would be a scheme akin to "Lunar Direct" that was a spinoff of "Mars Direct", but incorporating fuel depots and polar exploration in 3 phases, each with a differing yet complementary set of priorities that ends up with 2 useable bases and a propellant depot.

Phase I - "Oceanus"
Focusing on a straightforward return to the moon; "Oceanus" implies Oceanus Procellarum, as the initial site would be towards the lunar limb, whether it be the western or eastern.  The initial and majority of the flights are cargo, delivering a habitat, a telescope and geologic gear, 5 "utility" robotic rovers (think MERs with snowplows and on steroids), 3 crew rovers (think updated Apollo rover), and twin sets of ISRU modules that would gradually produce "building blocks" and LOX from regolith dug up by the utility rovers.  The crewed visits would range from a week to a full lunar day as the base components arrive, with their main purpose activating the outpost and local recon.  All flights would be direct, any rendezvous strictly in LEO, and if reuseable the crewed vehicles using aerocapture to return to LEO at mission's end.

Phase II - "Aquarius"
Propellants begin to become the focus, as does utilizing cislunar space.  Only 2 cargo flights are sent, the first being a self-contained LOX depot that's basically a flying H2 tank from SLS sent to wait at a LaGrange point.  The more numerous crew flights initially are fully fueled, but first begin hauling LOX on the return trip, and then using the depot for LOX both inbound and outbound.  While most flights revisit the equatorial limb base (ELB), 2 flights investigate other sites; one would be a "random" yet science-influenced site such as Copernicus or Aristarchus, while the second would be a polar region reasonably close to ice, such as Shackleton  or Peary.  The second cargo flight descends, delivering a habitat and rovers.

Phase III - "Frigoris"
With a habitat established at a pole, cargo flights descend to fully establish a smaller but water-focused Polar Base (PB).  As water is tentatively harvested at PB, back at ELB a new cargo flight delivers equipment to upgrade the base and maximize LOX production.  All crewed flights from the ELB stopover at the LOX Depot, refueling themselves but also restocking the supply before returning to LEO.  By the end 2 regions on the Moon are thoroughly explored, 2 differing sources of LOX are extracted, and the seeds are planted for self-sufficiency.

I will later add more to this thread, explaining the specifics of landers, ect.  For now this is a would-be architecture for a glance-over.

So you want NASA to mine lunar regolith to get oxygen, next you want NASA to go the Moon's polar region
to mine lunar water.

If mining regolith to get oxygen "works" why do you then want mine lunar water?

What I mean is mining water is for various uses as water, and one use is splitting water to make rocket fuel and that mostly gets oxygen- 8 kg of oxygen and 1 kg of hydrogen from 9 kg of water.

I would think one want to start with mining water, then proceed to mining other metals and a by product of mining say iron, is you get some oxygen. So both pure iron and the oxygen has value.

So, say wanted to make large telescope on Moon and it requires lots of metal, so mine the metals needed and also get some oxygen.

Now, what I think NASA should do is explore the Moon to determine if it would be profitable to mine lunar water- commercially.
« Last Edit: 03/19/2014 12:00 am by gbaikie »

Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #2 on: 03/19/2014 01:53 am »
So you want NASA to mine lunar regolith to get oxygen, next you want NASA to go the Moon's polar region
to mine lunar water.

If mining regolith to get oxygen "works" why do you then want mine lunar water?

Because dry lunar regolith is more common than ice, but water with its hydrogen are inevitably only at the poles.  One is more common but it'd be foolish not to harvest both.

What I mean is mining water is for various uses as water, and one use is splitting water to make rocket fuel and that mostly gets oxygen- 8 kg of oxygen and 1 kg of hydrogen from 9 kg of water.

I would think one want to start with mining water, then proceed to mining other metals and a by product of mining say iron, is you get some oxygen. So both pure iron and the oxygen has value.

That's one possibility many favor.  The two disadvantages I see is that we don't yet know how hard to get the ice is and, when refined to hydrogen, hydrogen is a pain to store; even in lunar shadow there is bound to be some boil-off.

Regarding metal, I suspect it will take some time to refine it to purity but there may be a simpler way to make lunar regolith useful: melt it into lunar concrete.  A lunar foundry would utilize the 14 days of sun to fry regolith (especially the leftovers from LOX production) into a crude but solid brick.  These bricks can be utilized to make initially small huts to test their strength, and next into the walls and structures of larger habitats.

Now, what I think NASA should do is explore the Moon to determine if it would be profitable to mine lunar water- commercially.

Agreed, but step one is to make a commercial lunar lander.  Getting back to the Moon will be enough of a challenge itself, technically and politically.
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Offline gbaikie

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Re: Dual-Moonbase Architecture
« Reply #3 on: 03/19/2014 08:31 am »
So you want NASA to mine lunar regolith to get oxygen, next you want NASA to go the Moon's polar region
to mine lunar water.

If mining regolith to get oxygen "works" why do you then want mine lunar water?

Because dry lunar regolith is more common than ice, but water with its hydrogen are inevitably only at the poles.  One is more common but it'd be foolish not to harvest both.

What I mean is mining water is for various uses as water, and one use is splitting water to make rocket fuel and that mostly gets oxygen- 8 kg of oxygen and 1 kg of hydrogen from 9 kg of water.

I would think one want to start with mining water, then proceed to mining other metals and a by product of mining say iron, is you get some oxygen. So both pure iron and the oxygen has value.

That's one possibility many favor.  The two disadvantages I see is that we don't yet know how hard to get the ice is and, when refined to hydrogen, hydrogen is a pain to store; even in lunar shadow there is bound to be some boil-off.
We don't know how hard or easy to get lunar ice.
And that is one reasons NASA should do lunar exploration.

As far as storing hydrogen. It's my assumption that you going to want liquid hydrogen to use as rocket fuel.
Therefore you going to start with relatively warm hydrogen gas and cool it down by refrigeration.
So if you cool hydrogen gas which warmer than say 280 K, one also has the ability to be able to cool hydrogen which 30 K or warmer. So you can add the colder hydrogen gas to the warmer hydrogen gas which you are refrigerating into liquid hydrogen.
If you assume the refrigeration will not be continuously operating, it seems there would little boil off if not operating for periods of days.

Another aspect is if have capability to make liquid hydrogen it means one has have ability to pressurize hydrogen gas, and could store high pressure hydrogen gas at say 1000 psi and at say less than 80 K:
http://yeroc.us/calculators/gas-density.php
Which at 1000 psi and 80 K it has density of 20.897 kg/m3. Which not dense as liquid hydrogen- liquid hydrogen is more than 3 times denser.
But if it's at 1000 psi and 300 K [26.85 C]  it's density is 5.5725 kg/m3.
And temperatures in dark crater can be about 50 K.
So pump the hydrogen gas in so tank warms up to 80 K, they store and let cool it down to 50 K. Then when you need liquid hydrogen, you draw gas from a tank which has chilled down to 50 K.

Another possibility is using even higher pressure, and use this higher pressure for vehicle use:
"Two approaches are being pursued to increase the gravimetric and volumetric storage capacities of compressed gas tanks from their current levels. The first approach involves cryo-compressed tanks. This is based on the fact that, at fixed pressure and volume, gas tank volumetric capacity increases as the tank temperature decreases. Thus, by cooling a tank from room temperature to liquid nitrogen temperature (77°K), its volumetric capacity will increase by a factor of four, although system volumetric capacity will be less than this due to the increased volume required for the cooling system."
http://www1.eere.energy.gov/hydrogenandfuelcells/storage/hydrogen_storage.html
[One also use high pressure and liquid hydrogen for vehicles]
So for mining vehicle you don't need to use liquid hydrogen, nor would vehicle need cooling system mentioned above to have the gas at  77°K.
So the default for hydrogen storage could be such level of high pressure hydrogen for vehicle use, and one than adds additional step to the process to make the liquid hydrogen for rocket use [when it's needed].
So this does take more tankage volume and stronger tanks.
This not much issue for surface vehicles, nor it huge deal storage tanks on lunar surface.
But it would be far too massive for spacecraft [though might be ok for short distance hopping vehicles]

« Last Edit: 03/19/2014 08:34 am by gbaikie »

Offline TrevorMonty

Re: Dual-Moonbase Architecture
« Reply #4 on: 03/20/2014 06:09 pm »
If the only significant ice is in the deep polar craters then extracting it maybe a step to far initially. Whipple crater is 10,000 ft deep, take a look at 10,000 ft mountain range from sea level and see what we are up against.
A base at 80% sunlight point on its crater rim is at highest point, any rover based exploring outside crater would require driving down steep outer crater rim first.

Establishing a base where exploration is not limited by mountainous terrain, is a better option. Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.

Offline gbaikie

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Re: Dual-Moonbase Architecture
« Reply #5 on: 03/20/2014 09:37 pm »
If the only significant ice is in the deep polar craters then extracting it maybe a step to far initially. Whipple crater is 10,000 ft deep, take a look at 10,000 ft mountain range from sea level and see what we are up against.
A base at 80% sunlight point on its crater rim is at highest point, any rover based exploring outside crater would require driving down steep outer crater rim first.

Establishing a base where exploration is not limited by mountainous terrain, is a better option. Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.

I think NASA should focus on exploration.
And Mars makes more sense for a NASA base in terms exploration.

A problem is that NASA does not have the funding to establish and operate many bases in space.
ISS is costing about 3 billion dollars per year to operate.
And I believe that NASA should do something with ISS to lower it's costs- so it possible for NASA can run another base in space.
I believe NASA actually needs to lower the cost on ISS before it can explore the Moon- when includes the fact  that NASA has decided it wants to be heavy lift launch company by it choice to develop SLS.
So NASA has now, 3 billion ISS, 2 billion dollar to slowly develop SLS [if had more funding it could develop SLS quicker], and once SLS is ready to launch, in order for it to vaguely be worth the billions already spent, on it, it will have have a higher operation cost as compared to it's current development costs.
So at 2017 SLS might have first launch, and thereafter it's budget will somewhere north of 3 billion per year and have ISS at 3 billion per year, which essentially means NASA does not have enough budget to do any other major exploration program.
If imagine that NASA is going to get major increase in budget *because*it's making a large rocket and operating a space station, I suggest you look at the history of NASA's budget:
http://en.wikipedia.org/wiki/Budget_of_NASA

I would say only way one could have NASA lunar base is if yearly costs is less 1 billion per year.
Roughly I would say you need rocket fuel at the Moon costing less than $5000 per lb and water less than $1000 per lb for this to be vaguely possible.

NASA does not need a lunar base in order to explore the Moon. And generally any base on a different world should only be built after one has done some exploration.
To be clear, NASA has not explore any world to date to adequate enough level to justify to putting any base anywhere.
But I believe NASA should explore the Moon, then it should explore Mars, and then put a base on Mars [or maybe Mars moons].
NASA need a base on Mars to assist in it's exploration of Mars- because Mars is long distance away from Earth.

And I would say if you favor NASA building a Lunar base, you essentially also saying, stop exploring Mars, unless the lunar base can be low cost [less than 1 billion dollars].
Now, I think NASA could get more yearly governmental funding, but I would say it's fair to say NASA has not and is currently not going in direction which one could expect this to happen.

So I suggest as way to get more funding, NASA must make space important to the people in Congress.
And would say that spread the pork around to congressional district, probably has worked to some extent in terms of increasing NASA budget, but it has not increased funding for what NASA is suppose to do- explore space.
So it's may have been helpful in terms a NASA as a job program.
So would say NASA the job program isn't going to get a lunar base or Mars base, particularly when realize the amount debt the US government has already acquired.
So because the US debt, it seems a fair bet that  job programs in future are not going to be a growth industry.

But what will be in high demand is what can create economic growth for US.
 So space exploration has caused economic growth in the past- and NASA as a job program not so much. And space exploration could, if done correctly, could create more economic growth in the future than it has done in the past.

So I would say NASA exploring the Moon to determine if there is minable water, is possible path to significant economic growth. And that future increases in NASA budget will related to how much economic growth is connected with NASA activity.
And if NASA exploration of the Moon, can result in commercial lunar water mining, then I think NASA exploration will seen as essential path to the Nation's economic growth- will be important and will get increases in funding.
« Last Edit: 03/20/2014 09:51 pm by gbaikie »

Offline JasonAW3

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Re: Dual-Moonbase Architecture
« Reply #6 on: 03/21/2014 07:27 pm »
I was just thinking.

     If you needed to cool something to cryogenic levels fairly quickly on the Moon, wouldn't a sort of reverse Geothermal plant work?

     Ok, here's the thought.  If the Moon's core IS essentiallty cooled completely off, then the Moon itself becomes a huge heat sink, dumping heat froom the surface during the lunar night and reflecting a good portion of it from the light grey regolith.

    If this is true, then the surface under about 2 or three meters ought to be at the very least subzero farenheit, and at 10 meters or more should be in the negative 100's or more.  I meantion this as it could have an effcet on any surface or subsurface bases we choose to put on the moon.

Mind you, even if the Moon's core is still partially moltant, the subsurface below 10 meters should still be hundreds of degrees below zero in temp.  (A loop into the crust could work as a semi-passive way to cool Hydrogen down to a liquid state).

Just a thought....

Jason
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Offline luinil

Re: Dual-Moonbase Architecture
« Reply #7 on: 03/24/2014 08:52 am »
If the only significant ice is in the deep polar craters then extracting it maybe a step to far initially. Whipple crater is 10,000 ft deep, take a look at 10,000 ft mountain range from sea level and see what we are up against.
A base at 80% sunlight point on its crater rim is at highest point, any rover based exploring outside crater would require driving down steep outer crater rim first.

Establishing a base where exploration is not limited by mountainous terrain, is a better option. Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.

A gondola system between the base of the crater an the rim would be a cheap and easy way to have a permanent access.  With lunar gravity you wouldn't need a lot of pillars so the work needed to build it would be minimal.

Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #8 on: 03/24/2014 09:19 am »
If the only significant ice is in the deep polar craters then extracting it maybe a step to far initially. Whipple crater is 10,000 ft deep, take a look at 10,000 ft mountain range from sea level and see what we are up against.
A base at 80% sunlight point on its crater rim is at highest point, any rover based exploring outside crater would require driving down steep outer crater rim first.

Establishing a base where exploration is not limited by mountainous terrain, is a better option. Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.

And that's exactly the point of establishing a simple equatorial base.  Put the initial focus on easy-to-access resources in a more benign region (at least in regards to landing).  Explore to poles to resolve the nature of the ice, but don't wrap the entire architecture around H2O; no eggs-in-one-basket people.  If 99% of the Moon is effectively waterless, we have to learn to work with that environment as much as figuring how to dig up ice.
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Offline luinil

Re: Dual-Moonbase Architecture
« Reply #9 on: 03/24/2014 10:00 am »
At the exception of landing, what are the advantages of an equatorial station?
No water, 2 weeks of continuous night wouldn't count as advantages. And now that we have a company that is working on pinpoint rocket landing in an atmosphere, I would guess that pinpoint landing on an airless body should not be a insurmountable problem.

Offline Hop_David

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Re: Dual-Moonbase Architecture
« Reply #10 on: 03/24/2014 02:55 pm »
Extracting LOX from regolith still gives you 80-90% of rocket fuel by weight.

Bipropellent needs oxidizer and fuel. Without fuel, oxidizer is worthless. For each 8 tonnes of oxygen produced you'd need to import a tonne of hydrogen.

What's it take to import a tonne of hydrogen?

Delta V from LEO to moon surface is about 6 km/s. It'd take about 7 tonnes of LEO propellent to get a 1 tonne payload to the lunar surface. A good fraction of  that tonne would be dry mass of tanks and rockets.

Without local fuel, the benefit of local oxygen is pretty much wiped out by the expense of importing fuel.

Plus oxygen extraction from ilmenite via pyrolysis is somewhat more difficult than melting and electrolyzing water ice.

Offline Robotbeat

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Re: Dual-Moonbase Architecture
« Reply #11 on: 03/24/2014 05:00 pm »
You don't have to run the rocket at the usual fuel-rich mixture. Running it stoic or even oxygen-rich would mean you only need maybe a tenth the mass.
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Re: Dual-Moonbase Architecture
« Reply #12 on: 03/24/2014 05:03 pm »
The notion of centering lunar surface missions around a dual base architecture, with phased development of those bases and of the activities associated with them, is a good one. It's a big vision! Without yet getting into any of the details, it is worth looking at some of the underlying assumptions.

First and foremost is the approach that involves pre-planned phases. It's natural (in our culture at least) to plan activities as a linear sequence: step 1, step 2, step 3, etc. That works particularly well if the end destination is known and the terrain between the starting point and the destination is well mapped. In exploration, though, that kind of knowledge is almost by definition not fully available. Handling that uncertainty means that often the plan needs to change -- sometimes dramatically -- along the way.

In contrast, consider the "capabilities-based approach" NASA is promoting for exploration with SLS/Orion. A path from where we are now to a single eventual destination isn't being clearly laid out. Instead NASA is trying to develop capabilities that will (might) be useful no matter what path forward is chosen. It is the "flexible path" approach.

I'm curious about this question: What are the first lunar surface capabilities that should be developed? I suggest they should be ones that will be "proximal" to current technology AND useful for a wide number of different approaches to lunar surface exploration.
« Last Edit: 03/24/2014 05:05 pm by sdsds »
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Offline Lar

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Re: Dual-Moonbase Architecture
« Reply #13 on: 03/24/2014 05:53 pm »
I'm curious about this question: What are the first lunar surface capabilities that should be developed? I suggest they should be ones that will be "proximal" to current technology AND useful for a wide number of different approaches to lunar surface exploration.

What technologies do you take as "already developed sufficiently" ? For example, we've landed on the moon before, fairly accurately. But it was a long time ago and NASA  has the Morpheus project... so must think refinement is justified.

Here's my list subject to modification from the above
- Landing and Takeoff
- Telerobotic manipulation of the environment (grading, digging, drilling, loading etc, as well as crushing, heating, screening, etc)
- ECLSS
- energy storage/production tech (I favor ICE over fuel cells or batteries but picking one and developing it as needed)
- Refining and chemical operations on the lunar (or martian) surface
- Hydroponics in low gee

These are useful for any planetary body and most are transferrable to zero gee (asteroidal) ops but some do have some forking, such as hydro and materials operations.
« Last Edit: 03/24/2014 05:55 pm by Lar »
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Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #14 on: 03/24/2014 06:59 pm »
At the exception of landing, what are the advantages of an equatorial station?
No water, 2 weeks of continuous night wouldn't count as advantages. And now that we have a company that is working on pinpoint rocket landing in an atmosphere, I would guess that pinpoint landing on an airless body should not be a insurmountable problem.

For starters, astronomically the equator offers better views of the night sky; the poles are fixed and target poor.  Geologically the poles are cratered highlands; of the two the SPA basin is of interest simply because of it's size and near the crust-mantle boundary with its depth; there is less variety of terrain in the north and outside of short roves crater rims are impossible to traverse on foot or wheels.

Pinpoint landing will be key to reaching the poles but simplicity trumps complexity, more so when it comes to ground operations.  Flat terrain is always better for rovers than deep inclines, and regardless of whether they land by rockets or have wheels, a ten-tone-plus piece of equipment will lean toward the grace of an elephant rather than a hummingbird.  Lessen the problem with an easier landing zone.
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Offline TrevorMonty

Re: Dual-Moonbase Architecture
« Reply #15 on: 03/24/2014 07:36 pm »
 Far side of moon is ideal for astronomy but not telerobotic operations which would be required to establish a base. Communications would need to be via L2 satellite with longer time delays or a network of satellites orbiting moon, either way it is extra infrastructure and costs plus another link in chain that can break.

A near side base can communication directly with earth. A underground base is ideal so somewhere with flat land for landers and hillside to tunnel base out of. The regolith composition is important, we need oxygen, metals ie Ti Al Fe and Si (future solarpanel manufacturing). Extraction of these resources may not happen for years but when it does we don't  what to move base.

Offline A_M_Swallow

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Re: Dual-Moonbase Architecture
« Reply #16 on: 03/24/2014 08:31 pm »

What technologies do you take as "already developed sufficiently" ? For example, we've landed on the moon before, fairly accurately. But it was a long time ago and NASA  has the Morpheus project... so must think refinement is justified.
{snip}

Astronauts frequently spend 6 months on the ISS.  Visits to the Moon Base are likely to be as long.  Consequently the fuel for the ascent stage has to be keep liquid for 6 months.

The outside temperature at the lunar equator can go from 100 K to 390 K.  Methane has a boiling point of −161.49 °C; −258.68 °F; 111.66 K where as hydrogen has a boiling point of −252.879 °C; −423.182 °F; 20.271 K.  The mass of any refrigeration system has to included in the structural mass, larger temperature differences need heavier refrigeration systems.

The extra payload mass Morpheus's engine can lift should allow more people in the cabin and thicker walls than the LEM.

Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #17 on: 03/31/2014 10:07 am »
I'll discuss the first element in my architecture: the cargo lander.

All together, it would be the most straightforward spacecraft in that it is meant to fly directly from Earth to the Lunar surface.  Much of my thinking about it stems from the Mars Direct Habitat.  Unlike Altair or Boeing's current concept for a reusable lander, access to the surface is the priority so that the autonomous utility rovers can embark and crews unload equipment as well as enter the base hab.  Fuel tanks, containing oxygen and methane, would sit atop either a habitat or container module with twin descent nozzles on either the sides or beneath the lander.

Being a cargo vehicle, there is no concern about needing an emergency escape or separate sets of tanks for descent/ascent stages.  The Altair engineering was impressive in coming up with ATHLETE as a means for offloading cargo from the descent stage, but it seems simpler just to put it low to the ground with the sides of the container unfolding into ramps.  Naturally there are concerns for obstacle clearance, but given the thought that goes into site selection (including polar sites) and our increasing database (thanks chiefly to LRO, SELENE, ect.) a rock smaller than a foot isn't a show stopper.  Fuel tanks and cargo, it would be a solid piece with minimal deployment mechanisms.

The math of course is the tricky part.  Mark Zubrin's designs for Mars Direct's hab massed it around 25 tons for all major elements; Altair would have been about 50 tons with 26 of it propellant.  While different designs, it implies that putting 25 tons on a one-way-moon-trip is possible.  Regarding science gear, for comparison the Hubble weighs just under 12 tons, so the telescope for the Equatorial Limb Base could be nearly as large (more likely 2/3 as sized to be conservative) with plenty of room for anything from heliophysics to seismology.  For items like the LOX and Foundry modules, I refer to Astronautics.com: http://www.astronautix.com/craft/lunox.htm  Gear for tentative ISRU seems to be placed around 7 tons, so giving 10 for LOX and another toward Foundries seems reasonable, with room leftover for more rovers, spares, feedstock hydrogen, and things like solar panels.

Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.
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Offline A_M_Swallow

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Re: Dual-Moonbase Architecture
« Reply #18 on: 03/31/2014 06:25 pm »
I'll discuss the first element in my architecture: the cargo lander.

All together, it would be the most straightforward spacecraft in that it is meant to fly directly from Earth to the Lunar surface.  Much of my thinking about it stems from the Mars Direct Habitat.  Unlike Altair or Boeing's current concept for a reusable lander, access to the surface is the priority so that the autonomous utility rovers can embark and crews unload equipment as well as enter the base hab.  Fuel tanks, containing oxygen and methane, would sit atop either a habitat or container module with twin descent nozzles on either the sides or beneath the lander.

Being a cargo vehicle, there is no concern about needing an emergency escape or separate sets of tanks for descent/ascent stages.  The Altair engineering was impressive in coming up with ATHLETE as a means for offloading cargo from the descent stage, but it seems simpler just to put it low to the ground with the sides of the container unfolding into ramps.  Naturally there are concerns for obstacle clearance, but given the thought that goes into site selection (including polar sites) and our increasing database (thanks chiefly to LRO, SELENE, ect.) a rock smaller than a foot isn't a show stopper.  Fuel tanks and cargo, it would be a solid piece with minimal deployment mechanisms.


Land 2 or 3 times at the same place and it becomes a spaceport.  Once empty the lander becomes a man made rock messing up a prime landing area.  The hazard needs removing.  Something like the ATHLETE is needed to move the lander to the side of the crater awaiting recycling.

Quote

The math of course is the tricky part.  Mark Zubrin's designs for Mars Direct's hab massed it around 25 tons for all major elements; Altair would have been about 50 tons with 26 of it propellant.  While different designs, it implies that putting 25 tons on a one-way-moon-trip is possible.  Regarding science gear, for comparison the Hubble weighs just under 12 tons, so the telescope for the Equatorial Limb Base could be nearly as large (more likely 2/3 as sized to be conservative) with plenty of room for anything from heliophysics to seismology.  For items like the LOX and Foundry modules, I refer to Astronautics.com: http://www.astronautix.com/craft/lunox.htm  Gear for tentative ISRU seems to be placed around 7 tons, so giving 10 for LOX and another toward Foundries seems reasonable, with room leftover for more rovers, spares, feedstock hydrogen, and things like solar panels.

Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.

There are various VTVL machines that can be space-rated to land small cargoes, which would allow new machines on the Moon within 5 years.

By putting several engines together you get a larger cargo lander.

On Earth the VTVL melt their concrete landing pads.  This heat will tend to damage any cargo near the nozzles.

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Re: Dual-Moonbase Architecture
« Reply #19 on: 03/31/2014 08:17 pm »
I'll discuss the first element in my architecture: the cargo lander.
[...]
Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.

Could you discuss the thinking behind this a bit? What provides your certainty that a non-reusable lander is required?
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Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #20 on: 03/31/2014 08:31 pm »
Land 2 or 3 times at the same place and it becomes a spaceport.  Once empty the lander becomes a man made rock messing up a prime landing area.  The hazard needs removing.  Something like the ATHLETE is needed to move the lander to the side of the crater awaiting recycling.

Inversely, landers could be spaced far apart and rovers haul the equipment to the base site.  All together there would be 5 cargo landers sent to the ELB and 3 to the PB, whereas manned versions (to be discussed later) would leave in one piece.  The lander designated for science gear would be the least critical to the base (the telescope possibly at risk from rocket exhaust & debris) it could be landed 5 miles away, within line-of-sight and communication, yet close enough for maintenance.

Regarding recycling, the propellant tanks would be especially of use since CH4/O2 has similar enough thermal needs that either could be utilized for LOX production, so landing vehicles within a mile of the site would be optimal.

There are various VTVL machines that can be space-rated to land small cargoes, which would allow new machines on the Moon within 5 years.

By putting several engines together you get a larger cargo lander.

On Earth the VTVL melt their concrete landing pads.  This heat will tend to damage any cargo near the nozzles.

Good point about rocket nozzles, so giving distance between landers with a designated field for reuseable ones is wise.  Considering the Moon itself is a great rock, minimal concern for ruining the terrain but concentrating where we land to preserve it likewise prudent.
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Re: Dual-Moonbase Architecture
« Reply #21 on: 03/31/2014 08:36 pm »
I'll discuss the first element in my architecture: the cargo lander.
[...]
Whether or not orbiting/LaGrange elements are later employed, a one-way cargo lander should be a must for either Mars or Luna, just to ensure something long-lasting is established at the intended destination.

Could you discuss the thinking behind this a bit? What provides your certainty that a non-reusable lander is required?

Reuseable for crews is applicable, but for the moment I discuss the cargo vehicle.  To maximize bringing 20+ tons to the Moon it would be on a one-way trip.  The only unmanned reuseable lunar vehicle worth considering would be a LOX hauler, but it would more likely be derived from the crew vehicle - basically replacing a crew cabin with an LOX tank.

To elaborate, bringing a 25 ton habitat down or the equal in other equipment will be tricky enough as the Moon requires a powered landing.  Unless you have a reason to return to Earth, it is more cost effective to put it on a one-way trip.
« Last Edit: 03/31/2014 08:43 pm by redliox »
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Re: Dual-Moonbase Architecture
« Reply #22 on: 03/31/2014 08:59 pm »
Ok, for reusable landers, why use only one main engine instead of lots of smaller engines. (say about eight to twelve smaller thrusters)

The configuration could have them at the upper four corners of the landing craft with an offset low pilot/passenger cabin for both viewing the landing easier as well as ease of access.  Cargos could be saddle baged over and around by the lander itself.  Some cargos could, in theory, be strapped to the upper strong back running the length of the lander design.
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Offline gbaikie

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Re: Dual-Moonbase Architecture
« Reply #23 on: 04/01/2014 12:15 am »
I'll discuss the first element in my architecture: the cargo lander.

All together, it would be the most straightforward spacecraft in that it is meant to fly directly from Earth to the Lunar surface.  Much of my thinking about it stems from the Mars Direct Habitat.  Unlike Altair or Boeing's current concept for a reusable lander, access to the surface is the priority so that the autonomous utility rovers can embark and crews unload equipment as well as enter the base hab.  Fuel tanks, containing oxygen and methane, would sit atop either a habitat or container module with twin descent nozzles on either the sides or beneath the lander.

Being a cargo vehicle, there is no concern about needing an emergency escape or separate sets of tanks for descent/ascent stages.  The Altair engineering was impressive in coming up with ATHLETE as a means for offloading cargo from the descent stage, but it seems simpler just to put it low to the ground with the sides of the container unfolding into ramps.  Naturally there are concerns for obstacle clearance, but given the thought that goes into site selection (including polar sites) and our increasing database (thanks chiefly to LRO, SELENE, ect.) a rock smaller than a foot isn't a show stopper.  Fuel tanks and cargo, it would be a solid piece with minimal deployment mechanisms.

In terms of structural loads, would say this design pushes rocket fuel and hangs the crew and cargo?
So you have some kind ring or donut which takes the load of engines on sides, giving compressional load to above it, and below the ring, the structure held up by tensional load, though lander gear would also need to be transferring a compression load up to this ring?



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Re: Dual-Moonbase Architecture
« Reply #24 on: 04/01/2014 01:58 am »
Reuseable for crews is applicable, but for the moment I discuss the cargo vehicle [capable of] bringing a 25 ton habitat down.

I'm beginning to understand your perspective! You seem to be saying, "For this architecture let's take as a given the use of an expendable, 25 t payload, cargo lander." Discussing what could be accomplished with such a vehicle, and at what cost, is definitely fun and probably worthwhile.

Quote
Unless you have a reason to return to Earth, it is more cost effective to put it on a one-way trip.

That's possibly a straw-man argument. Proponents of reusable lunar landers rarely propose returning them to Earth. They are usually seen as doing purely "surface to orbit and back" duty.
« Last Edit: 04/01/2014 01:58 am by sdsds »
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Re: Dual-Moonbase Architecture
« Reply #25 on: 04/01/2014 07:42 am »
I'm beginning to understand your perspective! You seem to be saying, "For this architecture let's take as a given the use of an expendable, 25 t payload, cargo lander." Discussing what could be accomplished with such a vehicle, and at what cost, is definitely fun and probably worthwhile.

Quote
Unless you have a reason to return to Earth, it is more cost effective to put it on a one-way trip.

That's possibly a straw-man argument. Proponents of reusable lunar landers rarely propose returning them to Earth. They are usually seen as doing purely "surface to orbit and back" duty.

I've read up a lot on the Mars Direct plans and believe there is merit to a "direct" approach in general.  Excess elements only add up to giving Congress more potshots to take at one's plans.  NASA seems insistent on including SEP, deep space habitats, ect. all in the name of crew safety...but good luck expecting ALL of that to get funded.  In the case of cargo though...just package it into a bundle and slow-boat it wherever; I don't recall any probes sending back signals that said "Are we there yet?  Are we there yet?" in protest to slow, fuel-efficient trajectories.

The next element I will discuss will be the LOX Depot, and after that the crew lander.  Each will have their own reasons I elaborate on.
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Offline TrevorMonty

Re: Dual-Moonbase Architecture
« Reply #26 on: 04/02/2014 12:31 am »
Until robotic ISRU is up and running, all cargo trips will be disposable landers. Once lunar fuel is available reusable landers become an option.
What ever cargo is going to be delivered to Lunar orbit will still need to be on a powered vehicle(eg Cygnus) to take it from TLI to a lunar orbit. Instead of transferring cargo to reuseable lander use a disaposable lander as cargo vehicle. The cargo vehicle/lander can dock with reusable lander which will perform the lunar deorbit burn, the landers then separate land separately.



 

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Re: Dual-Moonbase Architecture
« Reply #27 on: 04/02/2014 01:45 am »
Now onto the next element for discussion: the LOX Depot.  I will discuss the thinking behind it in two separate chunks: design and location.

LOX Depot I - Design

First off, when it comes to free-floating, orbital elements I am always skeptical of their use at best.  This is because of logistics and politics behaving at their worst.  Initially the space station was conceived as a true test bed and way station, an iconic final outpost near Earth where a fleet of vehicles would gather together before the grand march to Mars (or Moon in this case).  Problem is, if anyone remembers how the space shuttle typically operated, the news was full of "And today the launch was aborted...a second aborted launch...fourth...And today the Challenger exploded...".  Melodrama aside, even an optimist can't expect a space platform requiring a dozen launches to stay on a perfect, and low-budget, schedule; inevitably there could be a problem and if some lynchpin element is delayed (or worse destroyed) the effort ends up mothballed.  So why would I endorse one in my own schemes?

Firstly, Skylab in the '70s proved a HLV can launch a space station using propellant tanks as the station's core.  Second, we are finally entering an era of HLVs - namely SLS and Falcon Heavy.  At worst, 2 launches would be required: one to launch the fully prepped vehicle and the second a booster stage to get it where it needs to be - and this is my personal suggestion to any rocket scientists: do it in 2 or less launches.  Furthermore, it is always easier to build it on the ground than by rendezvous or spacewalks; initially the space station truss would have been built in orbit, but by the time the ISS was being constructed it was decided to put them together on the ground as much as possible and only leave simpler tasks to astronauts, like plugging in wiring and connecting pipes between the larger pieces.

Second, this won't be a manned vehicle itself.  No life support, no cabins.  It would have 2 docking ports at either end of it's long axis but, much like the ARM probe, they're only meant to hold the docked crew vehicle.  The primary function this depot is storing liquid oxygen for either fuel or breathing.  Regarding pumping the LOX around, consider the Russian Progress vehicle as well as Europe's ATVs, neither needed a spacewalk to setup a fuel transfer.  During docking, the outlets would be aligned to one another and connected automatically.  Without needing to babysit humans, the depot can focus purely on pressure and thermal regulation of LOX.

ULA conceived of a large depot design using a tank with an all-around sunshade.  Thus far that's the most practical idea I've seen.  Fuel depots using multiple retrofitted stages seem to unwieldy, and more specifically a third stage will not have the same capacity as they're small.

So basically the body of the depot is an SLS core oxygen tank with a port at either end and a pair of medium-sized solar arrays with a radiator at one end, much like the Skylab 2 concept.  Instead of a large wrap-around sunshade, a smaller one on one side should be enough.  The original Skylab employed simple sunshades and the JWST's shade technology is exactly what I'd have in mind here.  If this were put in LEO, the rapidly shifting sun would cause thermal havoc...but in high orbit (to be discussed in the next post) the whole depot could shift and rotate very slowly, keeping the shade against the sun while the tank body is naturally chilled coupled with the inherent tank insulation.  A large, independent, fuel depot receiving visiting landers that would pump LOX to-and-fro.

To keep with the purity of it's storage function, there would be no science and again no crew support.  One possibility that wouldn't detract from it: communication and navigation.  Because it's primary oxygen source would be the Moon, of course the depot will be fairly close to Luna, and with TDRESS and GPS deep in Earth's gravity well and useless to lunar expeditions this would make the depot the closest 'satellite'.  Two or 3 large, deployable antennas would stick out perpendicular to the arrays, one always pointed to Earth and the other Luna.  They would be gimbaled but fixed on their targets.  A more efficient possibility would be laser communication proved by LADEE; what better way to serve the Moon than offering high-speed internet with a tank of LOX?

Two further notes on this LOX depot design: it is optional, not essential.  All landers would be single vehicles capable of going straight to the lunar surface, and in the case of crew vehicles all the way back to Earth.  Once LOX production is tentatively established, which is the greater priority than the depot itself, would it be able to shine as crew vehicles, en route to Earth, make a pitstop to the depot to transfer LOX tanks filled on the surface.  It simply puts the LOX into space to make it applicable to even non-lunar spacecraft.  On top of this, the LOX depot could be expanded.  As I said, it would have 2 docking ports.  A profitable LOX industry might gain the nods of Congress and NASA to commission a second module that would link with the first, becoming 2 independently functioning tanks.  Furthermore, a second tank could store methane instead of oxygen, as the chemicals have similar thermal ranges (which is another reason Mars Direct suggested it and even Boeing's reuseable lunar lander would utilize it).  Hydrogen could be possible, but it would need a larger tank with even more insulation - hence why I focus on the oxygen with this depot.
« Last Edit: 04/02/2014 01:54 am by redliox »
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Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #28 on: 04/02/2014 04:46 am »
LOX Depot II - Location

Location, location, location is a large factor in Cis-Lunar space.  The simplest way to put it is the closer you are either the Earth or Luna the more expensive it becomes in both delta-v and fuel to move.  Even lunar orbit is unwise for reasons of gravity; the subtle mass differences between near side, far side, and within the lunar mantle have brought down satellites more than once.  So where does one stow a roughly three-story-tall LOX depot?

The Lagrange Points become the best sites, but amongst each other there are differences.  It requires extra force for the stable EM-4 and EM-5, and with EM-3 clear on the opposite side the choice comes down between EM-1 and EM-2...and I discovered an interesting factor: you can have both!

EM-2 has a slight edge over EM-1 in that you can reach LEO more easily, otherwise the points are equals...and this includes relative to each other.  Via lunar gravity assist, a spacecraft can actually migrate back and forth to EM-1 or EM-2 easily.  In fact, reaching either point or escaping Earth completely are equal to each other.

In general, I would place the LOX depot at EM-1, primarily to ease tracking it and so it can assist in communication.  However, when a mission to the far side is arranged, the depot and crew lander could link up, float over to EM-2, and the lander descends to explore with the depot's communication abilities assisting.  Afterwards, the sequence is reversed and the pair recouple to migrate back to EM-1, otherwise the lander could return directly to Earth while the depot returns to EM-1 solo.
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Re: Dual-Moonbase Architecture
« Reply #29 on: 04/02/2014 01:11 pm »
It's going to be hard enough to build one base, so don't propose building two.  Remember also, that there is plenty of regolith available at the poles for ISRU demos along those lines.
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Re: Dual-Moonbase Architecture
« Reply #30 on: 04/02/2014 01:35 pm »
Most of the mass to maintain a Space Station is unmmaned, so I think that the best approach is to use a ion tug and use only Earth-LEO conventional transport and use some ion ultraefficient tugs to reach the final destination. Xenon could be refilled.
So the rocket costs to build should be near to ISS. If new ways like reusable rockets could be used, plus inflatable modules, the costs should be reduced.

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Re: Dual-Moonbase Architecture
« Reply #31 on: 04/02/2014 02:26 pm »
It's going to be hard enough to build one base, so don't propose building two.  Remember also, that there is plenty of regolith available at the poles for ISRU demos along those lines.

The truly hard part, if any, is convincing an administration to return to the Moon.

I suggest 2 bases because there is more than one region to study and mine; some 99% of the Moon is nothing like the poles.  If 99% of the Moon is dry, we must work with it.  Ice or not, I don't think isolating flights to one site alone is the best way to return.  Suggesting a dozen bases is unpractical, but proposing one primary base supplemented by a smaller base combines the strengths of 2 regions.
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Re: Dual-Moonbase Architecture
« Reply #32 on: 04/02/2014 02:42 pm »
Most of the mass to maintain a Space Station is unmmaned, so I think that the best approach is to use a ion tug and use only Earth-LEO conventional transport and use some ion ultraefficient tugs to reach the final destination. Xenon could be refilled.

A designated ion tug would require a second launch and be painfully slow, but it would be feasible to use it on the LOX depot for instance at least as a station-keep mechanism and possibly to send it to EM-1/EM-2 by itself from LEO.

Otherwise regarding ion propulsion it may not be necessary for landers.  An SLS in either the 105 or 130 range can send a payload to the Moon on a 3 day trip directly whereas SEP demands weeks of slow boating.  Once the landers begins descent furthermore, it needs a chemical system to touchdown, and even in lunar gravity some of the giant solar arrays would be as frail as butterfly wings.

I'm a fan of SEP, but if there's a simple, clean way to reach the Moon in under a week use that avenue.
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Re: Dual-Moonbase Architecture
« Reply #33 on: 04/03/2014 08:03 am »
Otherwise regarding ion propulsion it may not be necessary for landers.  An SLS in either the 105 or 130 range can send a payload to the Moon on a 3 day trip directly whereas SEP demands weeks of slow boating.  Once the landers begins descent furthermore, it needs a chemical system to touchdown, and even in lunar gravity some of the giant solar arrays would be as frail as butterfly wings.

I'm a fan of SEP, but if there's a simple, clean way to reach the Moon in under a week use that avenue.
Ion is not appropriate for manned, but weeks is not a problem for unmanned cargo.
The idea is to try avoid to create new expensive rockets that we could not use for other thing instead massive and costly missions.
Instead, we could try a approach of constant "not too large" spending usign shared common rockets in a multinational approach, and increasing long duration reusable and modular infraestructure.

In other words, reuse the concept of ISS, but in a deep space and/or moon base, and begin with IRSU, asteroid and/or moon.
« Last Edit: 04/03/2014 08:07 am by Spaniard »

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Re: Dual-Moonbase Architecture
« Reply #34 on: 04/03/2014 08:11 am »
Otherwise regarding ion propulsion it may not be necessary for landers.  An SLS in either the 105 or 130 range can send a payload to the Moon on a 3 day trip directly whereas SEP demands weeks of slow boating.  Once the landers begins descent furthermore, it needs a chemical system to touchdown, and even in lunar gravity some of the giant solar arrays would be as frail as butterfly wings.

I'm a fan of SEP, but if there's a simple, clean way to reach the Moon in under a week use that avenue.
Ion is not appropriate for manned, but weeks is not a problem for unmanned cargo.
The idea is to try avoid to create new expensive rockets that we could not use for other thing instead massive and costly missions.

There is one major problem an ion drive would encounter within Cis-Lunar space: the Van Allen radiation belts.  Smart-1 used it in similar fashion but had to pass through the belts numerous times, and this was a factor in it's design.  Even with an improved set of thrusters, cargo sized for human expeditions would take even longer with the risk of damaging elements needed at the Moon like electronics and solar panels.  Given the choice, I would pick a swift path to the Moon versus the slow SEP.
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Re: Dual-Moonbase Architecture
« Reply #35 on: 04/03/2014 02:20 pm »
It's going to be hard enough to build one base, so don't propose building two.  Remember also, that there is plenty of regolith available at the poles for ISRU demos along those lines.

The truly hard part, if any, is convincing an administration to return to the Moon.

I suggest 2 bases because there is more than one region to study and mine; some 99% of the Moon is nothing like the poles.  If 99% of the Moon is dry, we must work with it.  Ice or not, I don't think isolating flights to one site alone is the best way to return.  Suggesting a dozen bases is unpractical, but proposing one primary base supplemented by a smaller base combines the strengths of 2 regions.
It reminds me of the US Antarctic program, where we have one large base (McMurdo) which is mostly a logistics hub (though obviously it does a lot of science too) and one smaller (though still relatively large) base (Amundsen-Scott) which is more pure research. This actually rather jives with my thinking lately, where I've been thinking that a reasonable goal for the space program would be to establish Antarctica-like activity on the Moon by the 2050s. I noticed that quite a lot of countries are entirely willing to fund some fairly expansive activity in Antarctica despite its harsh climate and lack of practical value (eg., McMurdo can support over a thousand people, there are specialized airplanes and ships needed for supplying the bases, and so on), yet there is little controversy over this and no eternal budget fight, at least not to my knowledge. So my feeling was that getting to such a position would stimulate or require development of a number of technologies that would reduce the cost of space travel, while also having considerable science value (which, as I am a scientist, I consider very important, particularly since the mid-term space program won't have a lot of immediate commercial or economic value), and generally move the space program towards that happy state where lots of good work can be done without requiring a huge political fight all the time.

Getting off of that, though, I would suggest that it's a bit much to expect establishing two permanent bases anytime soon. However, some people have suggested some really very clever concepts for large mobile bases--obviously smaller and less well-equipped than fixed bases, but still quite capable of supporting small crews traversing long distances for long periods of time. These might be a valuable adjunct to permanent fixed bases, where experiments requiring more infrastructure or particular characteristics (eg., the presence of frozen volatiles or peaks of eternal light, or farside bowl craters for radio astronomy, or so on and so forth) could be located, while the mobile bases traveled to sites of geological interest or to emplace experiments requiring characteristics not present at the main base site, such as small optical or radio telescopes. For the main base site, I think present knowledge heavily supports the poles, given their unique characteristics, while for a secondary site (if a fixed base is a must), I think the equatorial limb regions have significant attractions. I've been quite partial to Mare Smythii for a while...

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Re: Dual-Moonbase Architecture
« Reply #36 on: 04/03/2014 09:13 pm »
There is one major problem an ion drive would encounter within Cis-Lunar space: the Van Allen radiation belts.  Smart-1 used it in similar fashion but had to pass through the belts numerous times, and this was a factor in it's design.  Even with an improved set of thrusters, cargo sized for human expeditions would take even longer with the risk of damaging elements needed at the Moon like electronics and solar panels.  Given the choice, I would pick a swift path to the Moon versus the slow SEP.
I don't think it'd be a problem to turned off electronics. And the tug could have enough shielding to cross or even stay in the radiation belt without damage.

Manned is different. But manned is only a fraction of a base or a station.
It has no sense to repeat Apollo. If we return to Moon it should be to stay and thrive. A base and later develop ISRU. That's a lot of mass.

Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #37 on: 04/05/2014 11:02 am »
The third major element of my architecture concept: the crew lander.  While the LOX depot would be the largest, out of the 3 vehicles the crew lander would be the most complex for a variety of reasons, but foremost being the need to carry humans.  Second to that, the need to be reuseable.  The third, being a totally spacefaring vehicle akin to the Apollo LEM.  Since I have a lot to speak about, I will discuss it in 2 parts, beginning here with...

Crew Lander I - Design

Almost 20 years ago I saw some magnificent artwork by William Hartman depicted a modular lander visiting moons and asteroids in the solar system.  In many ways, that is exactly what we need nowadays to visit airless worlds.  This heavily inspired my crew lander concept.  In addition, during Altair's brief existence as a Constellation study and also the early 1990s FLO study (refer here on it: http://forum.nasaspaceflight.com/index.php?topic=34171.0 )  numerous designs were conceived of, ranging from bloated reincarnations of the a LEM to waspy, pallet-based horizontal landers.

I'll give a dry description.  The core would be a crew cabin akin to a slightly enlarged ISS module, except for the fact it would be octangular, not cylindrical, in cross-section.  At the base of the core cabin would be a single oxygen tank with a single LOX/CH4 main engine.  Meshing with 4 sides of the core's octagon are 4 slightly skinny methane tanks, each with a fuel line running to the main engine.  A separate line for oxygen runs vertically up one side of the core cabin, meeting with a port on top near the docking adaptor atop the vehicle to allow for LOX transfer between the lander and the LOX depot.  4 landing legs are spaced under each methane tank, though not directly supporting them.  The core cabin would be split into 2 parts internally: the upper part with the docking port and crew rooms while the lower part is storage and the airlock for lunar excursions.

The LOX tank is set low not just for convenience to the main engine but for convenience toward LOX refueling on the Moon.  While the LOX is fixed to the lander, the methane tanks could intentionally be detachable pods, removed either in LEO or on the lunar surface; an empty CH4 tank can thermally handle LOX needs making recycling useful toward base development.

There would be a hinged ladder on the airlock, but unlike Altair or FLO, this would be a minor hindrance as it would be no higher (or even shorter) than the LEM lander leg.  There would be minimal cargo transfer from the crew vehicle, so nothing of terrible bulk would move through it.

While the cargo lander would be sized for a dry (including cargo) mass of 25 tons, the crew version would be between 20-14 tons.  This is largely because the crew lander has to make a return trip beyond lunar orbit, whether to LEO or a Lagrange point.  With fuel, both landers would comes close to 40 tons, but naturally each lander uses it's respective mass differently.  Being one-way, the cargo lander puts more into surface payload while the crew lander more in propellant for a two-way trip.

More details to come, although this sets the crew lander's overall characteristics.
« Last Edit: 04/05/2014 11:07 am by redliox »
"Let the trails lead where they may, I will follow."
-Tigatron

Offline A_M_Swallow

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Re: Dual-Moonbase Architecture
« Reply #38 on: 04/05/2014 05:11 pm »
{snip}
I'll give a dry description.  The core would be a crew cabin akin to a slightly enlarged ISS module, except for the fact it would be octangular, not cylindrical, in cross-section.  At the base of the core cabin would be a single oxygen tank with a single LOX/CH4 main engine.  Meshing with 4 sides of the core's octagon are 4 slightly skinny methane tanks, each with a fuel line running to the main engine.  A separate line for oxygen runs vertically up one side of the core cabin, meeting with a port on top near the docking adaptor atop the vehicle to allow for LOX transfer between the lander and the LOX depot.  4 landing legs are spaced under each methane tank, though not directly supporting them.  The core cabin would be split into 2 parts internally: the upper part with the docking port and crew rooms while the lower part is storage and the airlock for lunar excursions.
{snip}

If you are willing to use 4-5 engines instead of one the prototype LOX/CH4 engine was flying around KSC last week.

Offline redliox

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Re: Dual-Moonbase Architecture
« Reply #39 on: 04/05/2014 09:12 pm »
If you are willing to use 4-5 engines instead of one the prototype LOX/CH4 engine was flying around KSC last week.

Nice!  If only it had been flying about during Altair's day Constellation might have moved forward.  Still it means LOX/CH4 propulsion is very viable, and because the two propellants have a similar liquid state easier to hold onto both versus H2.  Lunar and Martian tech should be made as interchangeable as possible.
"Let the trails lead where they may, I will follow."
-Tigatron

 

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