Moon is a Harsh Mistress - fresh discussion

[Quanders]

I noticed the threads right after the turn of the millenium, but, in the interest on Heinlein the contemporary - could we do him the sacred honor of a discussion of late?

I have a few questions I have not been able to get answered by searching reviews of his tale.

Generally, is it the earlier sf authors that seem to believe that lunar peoples will dwell underground? Radiation shielding, no doubt, but what about all the other orbiting hotels and colonies? Do they fare more weakened?

The catapult - - why do revolutionists utilize this and not a mass driver aimed at earth? (looking for a scientific explanation if can get) Does concealing the catapult override this possibility?

Moons gravity - hurtling rocks from the "~gravity advantage down to earth"
Is it true, from a point on the moon there is a potential downward fall toward earth?

Pressurizing wheat and other foodstuff containers en route to Terra.
Would this it really be necessary to pressurize food holds?

I see the writer's talent, and the value of the work, but some of these facts still linger.

 

[Urlik]

the catapult mechanism is already there and doesn't need much alteration to send a few tons of steel encased rock out of the Moon's weak gravitational field and into the Earth's.
by removing all the remote control thrusters for landing, the rocks have an effect sinilar to an atomic explosion, but without the radiation.
they are a large enough potential threat without the need for anything more complicated.
as for the pressurised containers, I think that is plot driven, although I have no idea wht the effect of a vaccuum would be on the foodstuffs in question

 

[ghost8772]

The catapult was a mass driver. Rail gun more specifically. they had the original, but its location was iffy and likely well known to officials on earth. they did build a secondary one as backup with no data on earth of its location.

Escape velocity from Moon is small, escape velocity from earth is much larger, no numbers on hand, but moon is listed as 1/6th gravitational acceleration. no an item on the moon is not going to be drawn to earth, if that was the case there would be a continuous flow of moon dust from the moon to earth's atmosphere. the moon has its own gravitational field, the point of separation is closer to the moon than earth, but its not on or really near the surface.

Yes most authors describe building colonies INTO the rock of a mostly airless planet. it does take more effort to open rock than multiple wall constructs. as I recall the only point in this book that was not dug into the surface was "the old dome" which they worried about taking collateral damage (no point could withstand a direct nuke attack)

the foodstuff sent to earth was compressed more to ship as little air and water, as well as most produce per package. larger profit per firing.

 

[chrispenycate]

Mass driver, yes, and the source of one of the few technical errors I caught Heinlein in; they didn't require steel shells, any reasonable conductor (like aliminium, for example , which could easily be extracted from the lunar regolith) would have sufficed. (he also had a tendecy to ignore the law of conservation of momentum occasionally, when it suited his purpose)
And I think the "undergroud"was as much for thermal reasons as radiation screening; the moon's day and night being so extended, the heat in the afternoon and the cold at night will both be extreme enough to make any Earthly desert seem very clement. A few metres of rock will reduce this cycle considerably.

And something coming in in free fall from lunar orbit would(if it weren't for air friction and the tendency to vaporise on the way down) arrive at more than ten kilometres/sec – that, for a few tens of kilogrammes is a lot of kinetic energy; baby dinosaur killer. No real advantage to chemical explosives after that, and they'd only render the missile more vunerable.

 

[Quanders]

chrispenycate,

Turning to other authors, like Robinson's 'Red Mars'/'Green Mars' - there is mention of surface domes with peizo cells that convert wind to 'sunlight'. This to me sounds plausible.

I think at some point, radiation will be engineered out by surface structures - applying to at least solar (even for sun storms) and cosmic background radiation. We may see those densely louvered surface buildings yet. Micro space debris could be tougher hazard.

Don't think my stance is due to conditioning by some of the more recent space artists, convincing as some of their portraits have the ability to argue.

Then too, there is the influence of the diurnal cycle. But I think life-like displays could help accomodate travellers with that.

The other point that struck me was having adjustment centrifuges for those facing or leaving transit. With lunar gravity and such, wouldn't it make more sense for the gee conditioning to occur in lunar orbit? (no downward pull, etc, but I'm guessing the Heinleins main advantage is no trip to L orbit required)

Don't mean to nitpick his rock of importance, but these points are important to my realization. Certainly leeway has to be alotted for what was discovered, post publish. Even though, for example, he does brieifly mention hydrogen mining. (not h+, and its surrogate titanium that often accompanies it's presence)

 

[Urlik]

in another Heinlein story, he has a powerful laser set up in the centre of a crater and then rotated to burn a level rim on the inside so that an inflatable dome can be sealed directly to the rock and then pressurised.

with the moon, a lot of tunnelling was done while mining.
as the population grew due to marrages between convicts producing offspring, it makes more sense to utilise the unused space below ground than build on the surface.

Mass driver, yes, and the source of one of the few technical errors I caught Heinlein in; they didn't require steel shells, any reasonable conductor (like aliminium, for example , which could easily be extracted from the lunar regolith) would have sufficed.

but was it known, or even suspected, that there was aluminium on the Moon when he wrote the book?
and anyway, steel would work so it isn't technically an error.

And something coming in in free fall from lunar orbit would(if it weren't for air friction and the tendency to vaporise on the way down) arrive at more than ten kilometres/sec – that, for a few tens of kilogrammes is a lot of kinetic energy; baby dinosaur killer. No real advantage to chemical explosives after that, and they'd only render the missile more vunerable.

considering the sizes of the containers used, I would estimate that there would have been several tons of rock per projectile, and if the ballistics were worked out well enough, the trajectory into Earth's atmosphere could be designed for maximum impact (although I wouldn't like to have to work out how much velocity is lost due to the atmosphere and what the impact speed would be, but I would expect to see a sizeable crater.
as for an advantage over chemical explosives, rock is cheaper, safer to handle and readily available

 

[Quanders]

Before finishing Mistress, something came to me. When the story starting telling of Great China.

Knowing their immense energy needs today, and their announcement of a desire for moon mining (h+)...there was one of those moments of realizing, heard before reading.

The story wraps with China building a catapult in the Himalayas, Tibet.

Now with China laying claim to sovereignty over Tibet - perhaps Heinlein was more a seer than most have recently come to discover.

 

[Pyan]

Now with China laying claim to sovereignty over Tibet - perhaps Heinlein was more a seer than most have recently come to discover.

Nice thought, Quanders - but China actually annexed the whole of Tibet in 1951 - The Moon was published in 1966, fifteen years after China actually did control the country.

I always imagine that Greater China, as RAH envisionaged it, would include Korea, Cambodia, Laos, Vietnam, and down through the Malay Peninsula. etc...isn't there a mention of Australia being part of it as well?

 

[Quanders]

pyan,

How can you deny what is going on between China and Tibet right now?

Are you saying Tibet isn't becoming less self-governing over its own peoples?

 

[Pyan]

If you read my answer properly, Quanders, you'll note that I made no comment on the present situation whatsoever.

Nice thought, Quanders - but China actually annexed the whole of Tibet in 1951 - The Moon was published in 1966, fifteen years after China actually did control the country.

Fact - China did annex Tibet in that year, predating the book by several years.

I always imagine that Greater China, as RAH envisionaged it, would include Korea, Cambodia, Laos, Vietnam, and down through the Malay Peninsula. etc...isn't there a mention of Australia being part of it as well?

Speculation - on what RAH envisioned Greater China to consist of.

Please show me where I am denying anything about the present situation, and where I mention the political set up regarding the governance of Tibet.

This is a book thread...If you want to comment on the Tibet question, there's always World Affairs...

 

[Quanders]

pyan,

You made nice points.

I was stating what I took to be most current reality.

Societal influences, and changes as it pertains to Mistress.
I guess I have a tendency to view things in terms of societal impact, rather than political milestones

Please show me where I am denying anything about the present situation, and where I mention the political set up regarding the governance of Tibet.

You're not, at least not flat-out explicity, though you did form your response somewhat as the explanation. I merely attributed his writing about Tibet as having futurist tendencies, (given the longer trend - then again, maybe some of this was sheer luck) while I think you see it as a condition already having been emplaced prior to the writing.

Now I see it as a mix of both. You see, I'm not one for categorical abstractions!

 

[Quanders]

- removed -

 

[Ursa major]

While some aspects of history are subject to debate, certain acts, like an army (in this case, the PLA) moving into a country, are not. (I'm sure I first read about it, decades ago, in the Reader's Digest, that well-known mouthpiece of the Chinese government, I don't think.)

Pyan didn't imply anything, he simply stated what happened in 1950.

 

[Urlik]

Pyan didn't imply anything, he simply stated what happened in 1950.

he actually stated 1951, but what's a year between friends?

 

[Ursa major]

That was my fault, Urlik, not Pyan's. The PLA first went into Tibet in 1950, but the formal annexation occured in 1951.

 

[Quanders]

I guess if you really want to be specifically fair - what was the Tibet's circumstance at the time of writing - 1966?

Had they regained independence or were they living under Chinese rule day-to-day. Talking trends here, as relates to Heinlein.

I don't know myself, I'm asking.
.............................................................

Also, anyone know of decent, recent sources on catapult development - Heinlein mentions building on West face of Mountain/higher elevations.

I'm wondering why the mass driver isn't being more seriously pursued right now.
(though I'm aware of 1+ bil development costs)

Whoever did so, it would seem, could potentially monopolize orbit payloads.
Something desperately needed right around the corner.

 

[Ursa major]

The Chinese "Cultural Revolution" (May 1966 - 1969) affected Tibet badly; perhaps this contributed to Heinlein's thoughts on the matter.

 

[Moogle]

Isn't a super collidor like the LHC just a particle level mass driver?

I'm not much in the science knowledge department, but let us not forget that in The Sixth Column Heinlein envisioned a world in which the Asiatic peoples of the East had united (I don't remember specifically whether it was through conquest or diplomacy), but they were able to conquer the United States specifically. Perhaps R.A.H. had seen what I'm sure other political scientists of the time had seen as the inevitability of a Chinese Superpower?

As to the OP's last question, remember that in Heinlein's version of the Lunar history, it is first used as a prison colony and work camp. I doubt that even much later in it's history there were many hotels or tourist attractions orbiting or even on the surface.

 

[ghost8772]

super colliders are particle accelerators. similar function, but designed to move smaller masses.

chrispenycate, the design of the catapult was more rail gun. using electromagnets, computer sequenced on powering up and down, to move a ferrous package. only a few ferrous metals out there, Iron and Nickel are two of the ones I recall. (total of 4?) iron/steel would still be the cheapest to produce, until the raw materials were depleted.

Underground ran several items at once. better insulation from light dark cycles. cheaper construction, since they would be taking away the parts that didn't work like habitation, instead of building all the parts of habitation, and paying carrier fees. Radiation is easiest to discount. considering how many people walked around in p-suits. most radiation can be minimized, or even negated through use of about 1" of metal sheeting. lead would be best of course.

 

[chrispenycate]

The trouble with the Earth based mass driver is atmosphere. The mountains aren't tall enough that you're not going to get enormous atmospheric friction , energy loss and heating. Look at the height when reentry heating starts to be a consideration for the shuttle; mountains are still tiny wrinkles below.
And the launching velocity would have to be much higher than reentry speed. Still, as a 'first stage' for a laser launcher, or even a chemical rocket or rocketplane, it could be useful.

the design of the catapult was more rail gun. using electromagnets, computer sequenced on powering up and down, to move a ferrous package

Rail gun, mass driver, they're all different names for the Laithwaite linear accellerator. A series of coils at steadily increasing spacing driven by a polyphase electrical current (or contant spacing with steadily increasing frequency if you so desire, but it's wasteful, so I'm sure Heinlein would have use increasing distances betwen coils, even if he used a variable frequency oscillator. The phase difference between ajacent coils produces a magnetic field moving along the axis of the coils. Any electrical conductor will get a current induced in it, which will generate an equal and opposite magnetic field which will tend to keep the conductive object centred in the magnetic peak (which is travelling at a steadily increasing speed along the series of coils.) This will work for any conductor, not just a ferromagnetic, as a number of dents in the IC elec eng building will testify; aluminium, brassm monkey metal (Laithwaite was an inspiring lecturer) Even salt water. I built my own with a lump of plastic drainpipe, and got teaspoons moving faster than sound. Weee!