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#1 2017-03-16 16:31:29

Oldfart1939
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Registered: 2016-11-26
Posts: 894

The Moon versus Mars; Science versus Economics?

Somehow, I simply cannot comprehend the enthusiasm for returning to the Moon. We have a bunch of rocks picked up 45 years ago, with little scientific revelations as a result. Mining? Resource extraction? The Moon is a desolate environment and at the present, has little to offer either scientifically or economically. About the only possibilities are, as GW suggested, a Nuclear Propulsion Test Facility, and a base for a monster radio telescope. For me, as a scientist (retired!) the return isn't there for the economic outlay. The only positive: it's NOT in LEO!

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#2 2017-03-16 16:39:05

GW Johnson
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From: McGregor, Texas USA
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Posts: 2,636
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Re: The Moon versus Mars; Science versus Economics?

Most of the support comes from government lab heads,  some politicians,  and the "old space" big corporations,  all of whom see the moon as something doable much faster and with less expense than Mars,  and with a lower chance of killing a crew.  I can't fault them for that,  but it is disappointing. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#3 2017-03-16 17:30:42

SpaceNut
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From: New Hampshire
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Posts: 10,375

Re: The Moon versus Mars; Science versus Economics?

Superiorism was all the race to the moon was about as very little was done in the name of science but nows its about showing that we still are capable to which its been in less than a mothed ball status and needing nearly a total restart.

If we want to show the way then we need to make going outward into space after the ISS model of cooperation and not of military might.

Sure there will be science to be done but it can also be done with making a settlement underground and a new world to allow for a cradle for man to branch out from once it stops thinking that science on the moon is all that should be done.

The moon should be a new station to which to build a pathway outward....

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#4 2017-03-16 17:44:32

Excelsior
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From: Excelsior, USA
Registered: 2014-02-22
Posts: 120

Re: The Moon versus Mars; Science versus Economics?

A) The use of lunar materials to produce future spacecraft will dramatically reduce the cost of said spacecraft.

B) The water needed to support the population needed to exploit those resources is limited and located in just a few strategic locations. The first to claim them holds the ultimate high ground into perpetuity.


The Former Commodore

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#5 2017-03-16 18:16:51

louis
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From: UK
Registered: 2008-03-24
Posts: 2,479

Re: The Moon versus Mars; Science versus Economics?

There are for me two reasons to return to the Moon. The first is lunar tourism which will be big business within 15 years. The second is as a proving ground for Mars life support and ISRU. Mars remains the real prize but the Moon has its uses.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#6 2017-03-16 18:25:08

RobS
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From: South Bend, IN
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Re: The Moon versus Mars; Science versus Economics?

I am a retired scientists as well, Oldfart--I have a Masters in Planetary Geology--and I totally disagree with you about the scientific value of the moon. We have learned vast amounts about the origin of the moon, the early history of the solar system, and the early development of the Earth as a result of the Apollo missions, and there is a lot more we still can learn. The way silicates differentiate in low pressure, low water environments inside the moon compliments our knowledge of their differentiation in the interior of the Earth and helps us understand silicate chemistry in general. That will help us understand the evolution of the interior of Mars, just as the surface of the moon teaches us about the surface of Mars. It has been estimated that every square kilometer of the surface of the moon has thousands of fragments of Earth, blasted into space by impact, that fell there. Dating those pieces of Earth will help us reconstruct the fist half billion years of terrestrial history and possibly figure out the evolution of the oceans, the atmosphere, and the origin of life on Earth. The moon is like Antarctica; a treasure trove for science. The moon and Earth are end members of a planetary spectrum with Mars half way in between, so the three of them teach us something about all three.

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#7 2017-03-16 18:50:50

Oldfart1939
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Registered: 2016-11-26
Posts: 894

Re: The Moon versus Mars; Science versus Economics?

For me, the Moon is something of a depressing place; work on the surface is limited to 14 days out of the Lunar cycle. Yes, there is something there for a Planetary Geologist to study, and the establishment of Astronomical observatories would also be worthwhile. Tourism? Yes, but getting there is more than half the fun! I'd go for the rocket ride myself, but one can get enough magnificent desolation in a day or two. "It's a nice place to visit, but I wouldn't want to live there." Mars on the other hand is a place for a chemist/biochemist/biologist to have some real fun.

Last edited by Oldfart1939 (2017-03-16 18:57:06)

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#8 2017-03-16 19:01:04

SpaceNut
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Posts: 10,375

Re: The Moon versus Mars; Science versus Economics?

That limitation is due to solar, so we will need nuclear to fix that problem...

So what are the possibilities of getting something other than RTG's for lunar use?

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#9 2017-03-16 19:10:53

Oldfart1939
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Registered: 2016-11-26
Posts: 894

Re: The Moon versus Mars; Science versus Economics?

We need to develop a compact and lightweight100-250 kWe Thorium-based nuclear reactor for off-Earth use. Could be used for both Moon and Mars.

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#10 2017-03-17 08:38:51

Terraformer
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From: Lancashire
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Re: The Moon versus Mars; Science versus Economics?

What reason is there for going to Mars, though? You're dealing with the same problem as Luna - there isn't a sufficiently compelling reason for either at the moment.

Get costs down, and we'll be able to justify a Lunar settlement, as well as a Martian one.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#11 2017-03-17 18:24:10

louis
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From: UK
Registered: 2008-03-24
Posts: 2,479

Re: The Moon versus Mars; Science versus Economics?

Thanks to Musk we are on the very cusp of that new era of cheap space travel.

Terraformer wrote:

What reason is there for going to Mars, though? You're dealing with the same problem as Luna - there isn't a sufficiently compelling reason for either at the moment.

Get costs down, and we'll be able to justify a Lunar settlement, as well as a Martian one.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#12 2017-03-17 23:18:25

Tom Kalbfus
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Registered: 2006-08-16
Posts: 4,401

Re: The Moon versus Mars; Science versus Economics?

SpaceNut wrote:

That limitation is due to solar, so we will need nuclear to fix that problem...

So what are the possibilities of getting something other than RTG's for lunar use?

There is a new type of solar cell called a thermophotovoltaic cell, and the way it works is this. this cell has two layers, the top layer absorbs visible light and gets very hot. the heat energy is transmitted to an emitter which emits photons in a wavelength that the photovoltaic cell underneath is optimized for converting into electricity, this can lead to solar conversion efficiencies greater than 30%.

FanFig1.jpg
http://web.stanford.edu/group/gcep/cgi- … d-emitter/

The thing about this solar cell is that it only works in a vacuum such as exists on the Moon, note the temperature difference indicated by the diagram. If there was air, it would convect heat away from the emitter and towards the photovoltaic cell reducing its efficiency be heating it up and reducing the emitters efficiency by cooling it down. Another important property is that it can convert stored heat into electricity as well. One can use the Suns light to heat up the thermophotovoltaic, and when the Sun goes down it will continue to convert the remaining heat to electricity until it cools down.

Last edited by Tom Kalbfus (2017-03-17 23:24:43)

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#13 2017-03-18 08:19:35

SpaceNut
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Re: The Moon versus Mars; Science versus Economics?

True but the length of day is 14 days and only at the poles is it continous, so any power level that is required needs to be twice as large to compensate for the need of any place other than the moons polar area.

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#14 2017-03-18 09:43:36

Tom Kalbfus
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Posts: 4,401

Re: The Moon versus Mars; Science versus Economics?

How large are the polar regions on the Moon?  The Moon is one quarter the size of Earth, it is a rather big rock! Much bigger than the two asteroids that are orbiting Mars, and closer to the Sun as well! The Lunar Poles aren't as forbidding as Earth poles are, the Solar rays are just as intense there as at the Lunar equator when the Sun is up. The Moon has very little axial tilt as well, that means you don't get 6 months of polar night as you do on Earth. The Sun's energy is just as freely available at the Moon's poles as they are to any spaceship in orbit. With the Moon you have building materials on site, in free space you don't! Instead of going through the trouble of building mass drivers to you can fling lunar materials into space for construction of SPS satellites in geosynchronous orbit, what if we just built lunar power stations on the Moon? those same solar panels on Earth would have to be vacuum sealed to get the same power efficiency. A laser could project power to Earth from the Moon, reflectors in Geosynchronous orbit can be optimized to reflect the specific wavelength of light projected by the laser, just as in a laser pushed light sail, the beam can be reflected around the Earth from wherever the Moon is, to touch down on a power conversion station in some convenient location on Earth. This is good practice for building some actual laser pushed light sails by the way!

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#15 2017-03-18 16:41:39

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 2,636
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Re: The Moon versus Mars; Science versus Economics?

I took a shot at bounding analyses for lunar cargo and crew landers,  and a revision in the lunar orbit variation of crew Dragon to go with them.  The cargo landers each deliver 5+ tons to the lunar surface,  and the crew lander ascent stage can carry as many as 6 back to lunar orbit.  Modified crew Dragon with 2800 kg of propellant stored in its trunk should be capable of returning 6,  even 7,  crew home from lunar orbit to an aerobraked and propulsive landing on land.

All these vehicles size at 13 metric tons thrown weight,  which Falcon-Heavy should be able to deliver all the way into lunar orbit,  flown fully-expendably.  Details posted over at http://exrocketman.blogspot.com,  in an article dated 3-18-17.  The idea behind this was not just to reprise Apollo 11,  but to start a small but more-or-less permanently-occupied base on the moon.  Benefits appear to be orders-of-magnitude greater than Apollo "flag-and-footprints",  while costs look to be orders of magnitude less than Apollo.  Timeline seems to fit within 1 or 2 presidential terms.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#16 2017-03-18 16:52:50

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 2,636
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Re: The Moon versus Mars; Science versus Economics?

I've commented on this before:  using local regolith materials as real engineering materials from which to construct things.  That is simply not a deployable technology today.  It will not be deployable for some time to come.  Why?  Because we simply do not know how to make real engineering materials out of rock dust,  whether it is magmatic or granitic. 

So,  whether you use it on-site,  or fling it into space by any means imaginable at all,  doesn't matter.  You still cannot do anything useful with it. 

This is a serious fault with all ideas of using lunar materials and/or asteroidal materials to build anything in the way of occupiable habitats.  That idea is still nothing but a pipe dream for our lifetimes.  Until we can make real steel (or something like it) in space and low-to-zero gravity from such resources,  the idea of building huge habitations out of in-space materials is just total and utter nonsense.  There's a whole lot more to it than just mass. 

Sorry to be the deflator of big ideas,  but some of those are still just way beyond anybody but God.  A dose of reality is always in order. 

GW

Last edited by GW Johnson (2017-03-18 16:55:31)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#17 2017-03-18 19:40:19

Tom Kalbfus
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Registered: 2006-08-16
Posts: 4,401

Re: The Moon versus Mars; Science versus Economics?

How about just heating up lunar materials to plasma temperatures breaking all chemical bonds and separating out the elements? I think heating the material to 6000 K ought to do the trick, that is the temperature of the surface of the Sun after all. Very large parabolic mirrors could do this I think. You'd need cooling equipment as well surrounding the area where you vaporize lunar material, the gases would condense back into solids upon contact.

Last edited by Tom Kalbfus (2017-03-18 19:42:16)

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#18 2017-03-19 03:30:13

Terraformer
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From: Lancashire
Registered: 2007-08-27
Posts: 2,437
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Re: The Moon versus Mars; Science versus Economics?

GW, a lot of the proposals just use the regolith for shielding. It seems to me that that is much easier to do than using them to manufacture pressure vessels. My own thinking is to sinter together blocks, which will be used to create an environment safe from radiation and abrasive dust, and inflate a habitat within it.


"I guarantee you that at some point, everything's going to go south on you, and you're going to say, 'This is it, this is how I end.' Now you can either accept that, or you can get to work." - Mark Watney

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#19 2017-03-19 09:16:29

Oldfart1939
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Registered: 2016-11-26
Posts: 894

Re: The Moon versus Mars; Science versus Economics?

About the only type of structures achievable in these early visits will undoubtedly be inflatables. Maybe a lightweight but very strong polymeric dome could be assembled there, but the abrasiveness of lunar dust will definitely degrade cloth fiber type materials. The problem of building radiation shelters is more extreme on the Moon than on Mars, minus any atmosphere.

Last edited by Oldfart1939 (2017-03-19 16:36:40)

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#20 2017-03-20 10:34:50

GW Johnson
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From: McGregor, Texas USA
Registered: 2011-12-04
Posts: 2,636
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Re: The Moon versus Mars; Science versus Economics?

The first thing that comes to mind is cylindrical modules coupled together laying in a trench,  that you cover-over with regolith. 

The second thing that comes to mind is erecting a strong patio cover over your hab modules on the surface,  and then putting a layer of regolith on top of that cover. 

The first requires less thrown weight,  but requires considerable deep digging.  The second requires more thrown weight,  but much shallower (therefore easier) digging.  Both require some sort of vacuum adapted electric rechargeable backhoe or front end loader.  Either would work on the moon or Mars. 

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#21 2017-03-21 04:32:52

elderflower
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Registered: 2016-06-19
Posts: 476

Re: The Moon versus Mars; Science versus Economics?

Any earth moving machine depends on its weight to provide friction that counters horizontal digging forces. With reduced weight on Mars or the Moon you will probably need to deploy some kind of counter weight full of loose regolith to dig in cohesive soils. Alternatively drilling and blasting will loosen the soil for you.

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#22 2017-03-21 21:30:50

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 10,375

Re: The Moon versus Mars; Science versus Economics?

Very true but that is an easy fix as we would want to make the machines as light as possible for shipping them to either place. The equipment just makes it easier to stay, to do the work and make science possible.

As for a vacuum suction vehicle we have these already and posted pictures of these in another topic.

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#23 2017-03-21 22:12:01

Oldfart1939
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Registered: 2016-11-26
Posts: 894

Re: The Moon versus Mars; Science versus Economics?

I personally like GW's idea of horizontal cylinders laid in trenches and covered by regolith. Reminds me of the 1950s backyard bomb shelters constructed to survive the blast and radiation from nuclear bombs. Structurally very strong, easy to manufacture, and could be transported by a Falcon Heavy.

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#24 2017-03-22 21:10:24

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 10,375

Re: The Moon versus Mars; Science versus Economics?

Things that we can do on the moon....
https://www.nasa.gov/pdf/163560main_Lun … ctives.pdf

Start with a cygnus can with a detachable lander stage and lay them into the trench and cover lightly. Since these come with docking ports we can just push them together to make it longer with each unit. These can be outfitted with what we need in each unit, sort of like laying the ISS on the ground.

Look at slide 12 of this link https://www.nasa.gov/pdf/163896main_Exp … 120406.pdf
This slide number 28 shows the small pressurized rover is on page 62 with the specs on page 67 plus on page 79 and digging unit which as the chariot vehicle carrage under the other parts which are mounted on it for use.  http://images.spaceref.com/news/2007/AI … E.2007.pdf

Since I would like to land the cygnus horizontal we will need a lander stage that can be coupled to the existing units which would be docked at the ISS. This stage would be a cradle design with loop over strapping to secure the cygnus at the station to the lander unit. To make the stage easier for first few designs and until we can make fuels on the moon I would think that current varieties of hydrogel would be the way to go.

Now we need to land a chariot truck on the surface for the ability to transport the cygnus from the lunar lander to the work site for base construction.

The cygnus modules would be simular to the iss building blocks with life support ect.. individually design for each unit to spread the parts for man to survive across that completed assembly. The center module should be the multiport nodes made by the same company for the central hub to build outward from. We could even have a cupola window view unit on this location.

How to use the moon for life support and more https://www.nasa.gov/pdf/203084main_ISR … 7%20V3.pdf

The last unit on each quadrants arm or wing of the base will stop with the clean up air lock room before entering the remaining part of the lunar base assembly. Just as you get outside in the space suit you will be able to enter either a simple lunar rover or a more advanced pressurize capable unit that is under the carport assembly.

Energy can be found on this link https://www.nasa.gov/pdf/203076main_TEC … 0Pitch.pdf

Affordable Fission Surface Power

Structural Definition and Mass Estimation of Lunar Surface Habitats

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#25 2017-03-23 21:43:57

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 10,375

Re: The Moon versus Mars; Science versus Economics?

Went back in and made a huge modification of the above post of which I am wondering if this even makes sense for a way forward when we do not have a viable lunar lander......

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