Return to the Moon?

[GarzaUK]

How can you return to the moon when you have never been?? :mrgreen: :mrgreen: :mrgreen: lol

 

[Thinker]

Oxygen on the moon is to be had by using solar mirrors to heat the AlO2 in the regolith, capturing the O2 in a bottle, and collecting the Al on a plate for future use in construction. Voila, oxygen and building materials.

Care to provide a reference that shows this is possible?

In the long term, water can be cheaply collected by mining comets. Cubic miles of water, if we want.

Cheaply? Using what technology? I would have thought that getting to Mars
(where we know there is plenty of water) would be far easier than chasing and
capturing bits of a comet (using technology that currently doesn't exist).

Also, there may be water in the lunar polar regions. That's not confirmed yet, but there's some indications.

So you would limit your lunar bases to the poles - the least useful places?

 

[Scarecrow Akhbar]

Care to provide a reference that shows this is possible?

Not really. Check out what Jerry Pournelle's written on the subject. If thermal separation is not possible, the alternative of using solar-electric separation certainly is.

Cheaply? Using what technology? I would have thought that getting to Mars(where we know there is plenty of water) would be far easier than chasing and capturing bits of a comet (using technology that currently doesn't exist).

Nope. Any water on Mars is deep inside a gravity well. That would require a significant delta-v to transport. Minining a comet doesn't have that hurdle. Then again, it's no different to fly to a comet than it is to mars. It's not much different to mine a comet than to mine mars....they'll still be wearing spacesuits.

So you would limit your lunar bases to the poles - the least useful places?

My, you have quite an imagination, don't you?

 

[The Mark]

Care to provide a reference that shows this is possible?

If he won't, I will.

http://www.asi.org/adb/04/03/10/04/oxygen-extraction.html

Cheaply? Using what technology? I would have thought that getting to Mars
(where we know there is plenty of water) would be far easier than chasing and
capturing bits of a comet (using technology that currently doesn't exist).

Maybe, but we really wouldn't need to do such a thing. However, getting to a comet actually might be easier than going to mars. If the comet is close enough. Since a comet wouldn't have much of a gravity well (I think), we could just fly along side it and harvest, and then leave when we are done. On mars we would need to use fuel to boost out of the gravity well to transport stuff to space.

So you would limit your lunar bases to the poles - the least useful places?

Not at all. Would it be so hard to transport water and such from the poles to another location? Say have a water collection location near the poles and then have the main base in a more usable location?

 

[Vandeervecken]

There's no problem in that at all. From a realistic perspective a trip to mars was completely unimaginable. Perhaps you are not as solidly grounded in the science and engineering required in such an undertaking thus making such claims.

Again this is hogwash. It was imagined. In fact detailed plans were laid out to do it, just congress didn't fund it. To say something humans have been imagining since prior to the Classical Greek Culture rose is unimaginable is frankly biazzare. In fact sine the end of the Appollo program we did indeed have the technoplogy to go to Mars, we simply lacked the national will to do so.

Not very much a life then.

A,h, nothing like a gratuitous insult to firther discredit what you are saying.

If you can not understand what it means to look at the feasability from a technological and practicality stand point then there's no point in going any further. I suggest you try reading.

You said the that Mars is as claose today as the Moon was in the 1970's. A silly and unsupportable statement by any creitrea. Actualy distance, travel time, or technological level. No matter how you slice it, you made an asinine claim.

Let me re-iterate and make it crystal clear for you.
I'm not saying by any way that the physical distance of Mars is as close as the moon is today. I'm referring to the engineering and technical ability of it makes a martian landing a closer reality then it was yesterday.

Well of course it gets easier as time and technology advances but that is neither here nor tehre to your claim.

If you still can nore understand this then you are purly reacting the way you are just to continue on a non-issue argument souly for the purpose of argument.

No, I am merely pointing out that you are talking out of your. . .hat. Your claim is unsupportable in any way shape or form. Your repeated claim that a trip to mars has been, "unimaginable," up until to today is especially silly when one looks at the number of books, films, short stories, poems, and scientific articles that have been published about this very trip for more than a century! In fact people have imagined traveling to the cosmos for as long as we have been recording words. Laughable.

 

[Vandeervecken]

sure we can get to the asteroids and sure we can mine them....but how long will it take to go there and get back? This isn't Star Trek so we can't just zapp across the galaxy at will.....yet....

We do not have to go there ourselves. Robot ships could go, and bring them into orbit around the moon for us to mine and send back to earth. One need not zap about the universe to send robotic ships throughout ones own solar system.

 

[jfuh]

Again this is hogwash. It was imagined. In fact detailed plans were laid out to do it, just congress didn't fund it. To say something humans have been imagining since prior to the Classical Greek Culture rose is unimaginable is frankly biazzare. In fact sine the end of the Appollo program we did indeed have the technoplogy to go to Mars, we simply lacked the national will to do so.[/QUTOE] YEs and in greek times people also attached feathers to their body to fly but flew to close to the sun and fell to the ground. Your twisting every point I'm making. During the Apollo program we barly made it to the moon. The rocketry was there, but the survivability was not as up to speed as it could've been. It was essentially a make or break for the moon, anything to beat the Russians. Mars is much more than simply the rocketry or the life support, but the endurance of isolation and the ability to adequately shield travlers from cosmic radiation since such travel would be without the protection of a magnetosphere. All of which is extra weight. Yet to reach mars requires much higher speeds than that required for a trip to the moon, and thus more fuel if a rocket is used.
So the answer from a practicality stand point is no, Mars was completely out of reach by humans in the 70's.

You said the that Mars is as claose today as the Moon was in the 1970's. A silly and unsupportable statement by any creitrea. Actualy distance, travel time, or technological level. No matter how you slice it, you made an asinine claim.

Again you are trying to make it seem like I was speaking of distance and travel time which I have time and again clearly stated was not what I had meant. Technological level is completley true. The moon seemed as out of reach in the late 50's as Mars seems today.
I challenge you to provide me with any practical solution for reliable travel to Mars today, mind you that 1 in 3 missions till this day to mars remains a failure.

Well of course it gets easier as time and technology advances but that is neither here nor tehre to your claim.

It has been the very basis of my argument since my first response to Mars vs the Moon.

No, I am merely pointing out that you are talking out of your. . .hat. Your claim is unsupportable in any way shape or form. Your repeated claim that a trip to mars has been, "unimaginable," up until to today is especially silly when one looks at the number of books, films, short stories, poems, and scientific articles that have been published about this very trip for more than a century! In fact people have imagined traveling to the cosmos for as long as we have been recording words. Laughable.

I ask you to provide a single scientific article that provides a fesable means of reliable travel to Mars from the 1970's. Which is what you are claiming right?

 

[jfuh]

We do not have to go there ourselves. Robot ships could go, and bring them into orbit around the moon for us to mine and send back to earth. One need not zap about the universe to send robotic ships throughout ones own solar system.

A single trip to mars today requires a good 6 month journey at fastest. A trip to the astroid belt would require up to a year. A "robotic" vessel that would need to tow efficient quantity of "fuel" would need to carry an astroid that is roughly 100 times it's mass in order to break even with the amount of energy required to get it there in the first place.
Total time frame would be nearly 3 years.
Yes it's completely unrealistic unless you can "zap" through the solar system.

 

[Scarecrow Akhbar]

I ask you to provide a single scientific article that provides a fesable means of reliable travel to Mars from the 1970's. Which is what you are claiming right?

NERVA K

We had the power plant.

Also, the Orion concept was developed in the 50's.

So we had two possible motors to use. What we lacked was the will.

 

[Scarecrow Akhbar]

A single trip to mars today requires a good 6 month journey at fastest. A trip to the astroid belt would require up to a year. A "robotic" vessel that would need to tow efficient quantity of "fuel" would need to carry an astroid that is roughly 100 times it's mass in order to break even with the amount of energy required to get it there in the first place.
Total time frame would be nearly 3 years.
Yes it's completely unrealistic unless you can "zap" through the solar system.

Oh, like we couldn't use mirrors to heat asteroidal material and eject it through a nozzle to generate thrust? The energy source isn't on board, so that's a savings. Then it's a matter of how big a rock to push, and where to.

No need to "tow" anything.

You are aware that whaling voyages in the 19th century lasted three years or more at times? Of course, that was when men were men, not little whiners...

 

[Thinker]

Any water on Mars is deep inside a gravity well.

Why is this relevant? I was suggesting going to Mars rather than the moon. In
that case you want the water on-site; there is no need to lift it from the
planet.

My, you have quite an imagination, don't you?

I do, but that's not addressing my point. The most useful place for a lunar base
would be the far side, where an observatory would be shielded from interference
from the Earth. The poles would be useless for this.

 

[goligoth]

A single trip to mars today requires a good 6 month journey at fastest. A trip to the astroid belt would require up to a year. A "robotic" vessel that would need to tow efficient quantity of "fuel" would need to carry an astroid that is roughly 100 times it's mass in order to break even with the amount of energy required to get it there in the first place.
Total time frame would be nearly 3 years.
Yes it's completely unrealistic unless you can "zap" through the solar system.

That is what I was trying to get at...thank you....

 

[earthworm]

I voted no because going to the moon achieves little. It's a poor base for further
exploration as almost everything needs to be brought from Earth.

A direct mission to Mars must be the next step; going via the moon would be
wasteful in time and energy.

Partially agree;but what we really need to work on is eradicating fear and ignorance on earth, and this is far more difficult to do...
We could send all the Islamics to the moon ! :mrgreen: Just kidding.

If mankind does not soon learn to live together in peace, there may be no earth from which to launch any space exploration..

 

[The Mark]

Partially agree;but what we really need to work on is eradicating fear and ignorance on earth, and this is far more difficult to do...
We could send all the Islamics to the moon ! :mrgreen: Just kidding.

If mankind does not soon learn to live together in peace, there may be no earth from which to launch any space exploration..

I've wondered at times what might get most (note that I did not say all) of the people on earth to work together.

So far, I have a few ideas, but most of them sprouted from my own likes and dislikes, so they are in all probability different from what would actually work.

At times I have thought that a world-funded space program might work, but the problem with that is that a large percentage of the worlds population is much more interested in what happens here on earth than it is in what happens in space. Sure, the odd spectacular event draws attention, but on the whole, places out of our atmosphere are of little concern to many. At least that is my impression. And there are probably many more problems with that idea than I can see, with my limited point of view.

 

[DeeJayH]

I've wondered at times what might get most (note that I did not say all) of the people on earth to work together.

So far, I have a few ideas, but most of them sprouted from my own likes and dislikes, so they are in all probability different from what would actually work.

At times I have thought that a world-funded space program might work, but the problem with that is that a large percentage of the worlds population is much more interested in what happens here on earth than it is in what happens in space. Sure, the odd spectacular event draws attention, but on the whole, places out of our atmosphere are of little concern to many. At least that is my impression. And there are probably many more problems with that idea than I can see, with my limited point of view.

I would say that is a fair generalization of most people
the old 'not in my backyard' slogan comes to mind along those lines

 

[Scarecrow Akhbar]

I do, but that's not addressing my point. The most useful place for a lunar base would be the far side, where an observatory would be shielded from interference from the Earth. The poles would be useless for this.

My comment on your boundless imagination was on your assertion that I was restricting lunar occupation to the polar regions. Nothing I said can be construed to mean that.

Also, unless the moon's orbit has changed, or it's angular momentum vector, there are lunar polar regions that are not visible from the earth, so your claim that polar sites are not suitable for an observatory is flat wrong.

Also, of course, is the concept of long term occupation of the moon would almost certainly include rail travel powered by a solar electric grid, which would mean that just about anywhere on the moon is a good place.


Hmmm....how fast could a train on the moon go...no air friction...we have maglev trains here...so we could eliminate rail friction, too....it could go really damn fast, easily a thousand miles an hour, I bet....and the moon is only 6000 miles in circumference...so three hours to anywhere...nice.

 

[jfuh]

Oh, like we couldn't use mirrors to heat asteroidal material and eject it through a nozzle to generate thrust? The energy source isn't on board, so that's a savings. Then it's a matter of how big a rock to push, and where to.

No need to "tow" anything.

You are aware that whaling voyages in the 19th century lasted three years or more at times? Of course, that was when men were men, not little whiners...

You have any idea of how large the mirrors would have to be? I'm not saying it's impossible, I'm saying its unrealistic and improbable.

 

[jfuh]

NERVA K

We had the power plant.

Also, the Orion concept was developed in the 50's.

So we had two possible motors to use. What we lacked was the will.

Go back and read the articles you posted. Both concepts had serious containment issues at the time, not to mention that launching these "motors" possed a serious gamble with the containment capsules to be ruptured which happened in the 60's.
Not to mention that back in that time the technology for orbital assembly did not yet exist for the ability of an assembly of a large craft, thus would've required the "one launch" approach. Unfortunately there also did not exist the lift capacity for such heavy shielding.
Finally, public launch of a nuclear craft would've represented a serious threat to the schizophrenic Soviets. Not something I think that anyone would've wanted to see happen.

 

[jfuh]

I've wondered at times what might get most (note that I did not say all) of the people on earth to work together.

So far, I have a few ideas, but most of them sprouted from my own likes and dislikes, so they are in all probability different from what would actually work.

At times I have thought that a world-funded space program might work, but the problem with that is that a large percentage of the worlds population is much more interested in what happens here on earth than it is in what happens in space. Sure, the odd spectacular event draws attention, but on the whole, places out of our atmosphere are of little concern to many. At least that is my impression. And there are probably many more problems with that idea than I can see, with my limited point of view.

Honestly? I think an Alien invasion would get everyone working together. Finally, those religious fanatics willing to strap bombs to themselves are no longer seen as an annoyance.

 

[jfuh]

My comment on your boundless imagination was on your assertion that I was restricting lunar occupation to the polar regions. Nothing I said can be construed to mean that.

Also, unless the moon's orbit has changed, or it's angular momentum vector, there are lunar polar regions that are not visible from the earth, so your claim that polar sites are not suitable for an observatory is flat wrong.

Also, of course, is the concept of long term occupation of the moon would almost certainly include rail travel powered by a solar electric grid, which would mean that just about anywhere on the moon is a good place.


Hmmm....how fast could a train on the moon go...no air friction...we have maglev trains here...so we could eliminate rail friction, too....it could go really damn fast, easily a thousand miles an hour, I bet....and the moon is only 6000 miles in circumference...so three hours to anywhere...nice.

You have good imagination for concepts that are grounded in some science. However nearly all your concepts are grounded in unpractcal approaches otherwise are approaches that are too distant of a future than what is possible today.

 

[Scarecrow Akhbar]

You have any idea of how large the mirrors would have to be? I'm not saying it's impossible, I'm saying its unrealistic and improbable.

I'm saying that you don't know what you're talking about.

Here's a couple options to consider.

1) The mirror is at the rocket. While I'm not going to calculate how big the mirror would have to be (critical variables: distance from sun, mass of asteriod, desired thrust, and fusion point of material to be ablated), one can assume that it'll be pretty big. I'll make some guesses.

Let's assume that our favorite rock is 1 mile in diameter and is of mostly nickel iron. That rock has a mass of 58 billion pounds.

If we seek an acceleration of 0.01 ft/sec2, our thrust must be 580 million lbs. Our Saturn V rockets with a cluster of five F-1 engines produced a thrust of 7.5 million pounds. That's chemical rocketry, limited by the stored energy of the chemicals and the mass thereof. But scaling up by a factor of 80 isn't unreasonable.

After 100 seconds of thrust, the velocity of the rock has been altered by a 1 ft/sec vector. Given time, and we have plenty of that, we can warp that rock's orbit as we need to.

580 million pounds of thrust impossible? If we get 1/10 the thrust, it merely takes ten times longer to push it. Patience.

Now, let's suppose we can only deploy a small mirror (design factors: expected thrust, jitter, strengths of materials), say two thousand feet in diameter. I'm certainly not going to do a full blown design, but if the thing was 0.001 in thick aluminum (household foil), the reflective surface would weigh a mere 23 tons. Now, there's spars, struts, stiffeners, and other junk, so the mirror might weigh a couple hundred tons. That definitely requires detailed analysis and modelling to narrow down.

Clearly, we're not making such a deployable gadget until lunar resources are available (rich in aluminum, ya know...)

But play with the variables, and clearly this option is possible.

2) Is it necessary to have the primary mirror at the point of application? No. In fact, it would certainly be more cost effective to have the mirror someplace where it can be used more often. Put the primary in close orbit about the sun, say... around Mercury. Point a concentrated, but not super-hot, beam of sunlight at the rock out in the asteroid belt. Use smaller local mirrors (cheaper) to collect and focus as needed. When boost phase for that rock is over, shift the primary to another rock and repeat.

The same 100 ton mirror, 30 million miles from the sun, would collect and transmit 100 times as much energy as something 300 million miles away.

So, the power's there, if someone can find a market for it and investors to tap it. Only a matter of time, I suppose.

------

Now, I"ve limited my discussion to simple aluminum. It's a common material, cheap, very easy to work with, we've lots of experience with it, and it's suitable for the space environment.

There's more exotic materials, but this is a quick and dirty back-of-the-envelope post. But the mirrors would work. It's just sunlight.

 

[Scarecrow Akhbar]

You have good imagination for concepts that are grounded in some science. However nearly all your concepts are grounded in unpractcal approaches otherwise are approaches that are too distant of a future than what is possible today.

Oh, the maglev train is proven technology.

The lack of air on the moon is observed fact.

What's more expensive, building a rail road (something even civil engineers can figure out), or running point to point rockets everywhere? Rockets cost fuel to run. They're good for unexplored or seldom visited spots, but if there's ever two cities on the moon, they'll be linked by rail.

My approaches are totally practical. And who was restricting our discussion of moon colonization to the rest of this century? By 2100, we'll have a quonset hut up there, at current rates.

So long as the world wastes money supporting people who refuse to work, the human race will be unable to reach it's destiny.

 

[Scarecrow Akhbar]

Go back and read the articles you posted. Both concepts had serious containment issues at the time, not to mention that launching these "motors" possed a serious gamble with the containment capsules to be ruptured which happened in the 60's.
Not to mention that back in that time the technology for orbital assembly did not yet exist for the ability of an assembly of a large craft, thus would've required the "one launch" approach. Unfortunately there also did not exist the lift capacity for such heavy shielding.
Finally, public launch of a nuclear craft would've represented a serious threat to the schizophrenic Soviets. Not something I think that anyone would've wanted to see happen.

Oh, like I'm not aware of the Treaty of Moscow? I said the technology was there. I didn't say legal hurdles didn't exist, not to mention that no one in their right mind would light nuclear thermal rockets in the atmosphere as a routine event. No. The rocket would have to be launched chemically (Saturn had the capacity), and the vehicle assembled on orbit. Gee, I guess that's something we got to learn how to do sometime. They could have started back then.

 

[jfuh]

I'm saying that you don't know what you're talking about.

Here's a couple options to consider.

1) The mirror is at the rocket. While I'm not going to calculate how big the mirror would have to be (critical variables: distance from sun, mass of asteriod, desired thrust, and fusion point of material to be ablated), one can assume that it'll be pretty big. I'll make some guesses.

Let's assume that our favorite rock is 1 mile in diameter and is of mostly nickel iron. That rock has a mass of 58 billion pounds.

If we seek an acceleration of 0.01 ft/sec2, our thrust must be 580 million lbs. Our Saturn V rockets with a cluster of five F-1 engines produced a thrust of 7.5 million pounds. That's chemical rocketry, limited by the stored energy of the chemicals and the mass thereof. But scaling up by a factor of 80 isn't unreasonable.

Just how do you propose to scale up to such a factor? 80 Saturn V rockets? And the fuel comes from where?

After 100 seconds of thrust, the velocity of the rock has been altered by a 1 ft/sec vector. Given time, and we have plenty of that, we can warp that rock's orbit as we need to.

Do we? You're using a chemical rocket, time is something you do not have.

580 million pounds of thrust impossible? If we get 1/10 the thrust, it merely takes ten times longer to push it. Patience.

You really have no idea of how rediculously impractical your approach is do you.

Now, let's suppose we can only deploy a small mirror (design factors: expected thrust, jitter, strengths of materials), say two thousand feet in diameter. I'm certainly not going to do a full blown design, but if the thing was 0.001 in thick aluminum (household foil), the reflective surface would weigh a mere 23 tons. Now, there's spars, struts, stiffeners, and other junk, so the mirror might weigh a couple hundred tons. That definitely requires detailed analysis and modelling to narrow down.

Mere 23 tons? Have you any idea in your head of how impossible it would be to launch a single ton?

Clearly, we're not making such a deployable gadget until lunar resources are available (rich in aluminum, ya know...)

But play with the variables, and clearly this option is possible.

Still improbable and highly highly unrealistic.

2) Is it necessary to have the primary mirror at the point of application? No. In fact, it would certainly be more cost effective to have the mirror someplace where it can be used more often. Put the primary in close orbit about the sun, say... around Mercury. Point a concentrated, but not super-hot, beam of sunlight at the rock out in the asteroid belt. Use smaller local mirrors (cheaper) to collect and focus as needed. When boost phase for that rock is over, shift the primary to another rock and repeat.

Dream on rocket boy.

The same 100 ton mirror, 30 million miles from the sun, would collect and transmit 100 times as much energy as something 300 million miles away.

Nope, not true at all, too much scattering.

So, the power's there, if someone can find a market for it and investors to tap it. Only a matter of time, I suppose.

From your proposal, it's a matter of never happening.

Now, I"ve limited my discussion to simple aluminum. It's a common material, cheap, very easy to work with, we've lots of experience with it, and it's suitable for the space environment.

There's more exotic materials, but this is a quick and dirty back-of-the-envelope post. But the mirrors would work. It's just sunlight.

Again, too much scattering.
Like I've said, good imagination, but completely unrealistic.

 

[jfuh]

Oh, like I'm not aware of the Treaty of Moscow?

from the way you worded it? no.

I said the technology was there. I didn't say legal hurdles didn't exist, not to mention that no one in their right mind would light nuclear thermal rockets in the atmosphere as a routine event. No. The rocket would have to be launched chemically (Saturn had the capacity), and the vehicle assembled on orbit. Gee, I guess that's something we got to learn how to do sometime. They could have started back then.

Even till today with the assembly of the ISS we're still not very good at orbital assembly.
The original argument was the probability of launching a manned martian mission in the 70's. The answer is a simple no.