an engineering problem which I need to solve for a story

[the neurovore of Zur-En-Aargh]

This refers to a bit of historical background for the next volume in the series of Thing I Want To Be Working On.

I have a human colony planet that is, between a combination of not having the right materials, losing some background knowledge, and having a government that is heavily down on research and progress and generally sort of stagnant, for the most part stuck at just-post-WWII tech levels. They have a fairly significant space presence, but it's been put there by brute force application of late 40s equivalent technology. (Sea Dragons!) They wanted to launch a large chunk of material to their moon for building with; a hundred-thousand-tonne or so total weight solid metal bullet packed with useful ores and things, launched with a suitably large nuclear explosion, and lithobraking on arrival. (Yep, there are bad consequences to setting off that large an explosion on one's planet; postulate a nihilistic imperium that is indifferent to some forms of collateral damage and actively welcomes others as signs of divine favour.)

I'm pretty good with most of what's needed to make this work - it's basically Jules Verne's Baltimore Gun Club writ large, except with realistic physics. My issue is that while smashing this thing into their moon and leaving a large crater with thousands of tonnes of metal buried in it is fine for delivering iron &c. one then intends to mine, I need somebody to hide a Significant Plot Object on the thing for later retrieval after its journey, and the Significant Plot Object has to make it through the journey intact. The Significant Plot Object can have plausible good real-world material strength (you can think of it as made of diamond or jade) but not be made of magic handwavium, and it can be cushioned by any plausible protective casing one could have made in, oh, 1948 (or say by 1960 if the technology to make it is something that works as an offshoot of tech development rather than having half a dozen other implications and obvious uses that mess up the setting) though the smaller and more discreet that protection is the better, and the upper limit would be, say, one standard shipping container; the object itself is small enough to hold in one hand.

So, anyone got recommendations for an engineering solution, or for good references/resources allowing me to figure one out ?

[LDWriter2]

I have no idea how to answer that, even though I might come up with something in a few days but the real reason I respond is to say that I may know some place--a full writer's forum where there are people who might know.

[Serack]

Suggestion.

This isn't an engineering suggestion but rather a paradigm suggestion.

How this Significant Object survives could (should?) be closely tied to its signficance.

If the object is significant because of the info it contains, then have it deformed in ways that preserves the information, but otherwise be fubar'd.  Heck, you could even have some of the information lost in such a way that the stiching together of what is left is plot relevant.

Now replace "information" with what is Significant about your object.

[Haru]

The first thing that comes to mind is sort of a pressure cooker, although that might be more steampunk rather that your time period. The idea would be to build a gigantic canon with an even bigger pressure tank below it, to give it a big chunk of speed from the start. After that, you can have some rocket contraption to maneuver it the rest of the  way.
Heating up the pressure tank would probably not be easy by conventional means, so I would suggest building it on top of a volcano, so the hot lava will create the heat you need to create enough pressure. The whole thing build sort of like an artificial geyser with a giant cork on top, and then you loosen the cork so it flies pow, right to the moon.
Volcanos and mad science is always a great combination

[the neurovore of Zur-En-Aargh]

If the object is significant because of the info it contains, then have it deformed in ways that preserves the information, but otherwise be fubar'd.

This is in fact the case; the long-term plot relevance is for that information to have survived and got out in a context where it's thought to have been lost.

The problem is, finding a physically plausible means of storing rather a lot of information in a small space (even using remnant tech from higher tech levels, I want not to have to break physics here) that can readably survive the stresses of the launch and landing.

[the neurovore of Zur-En-Aargh]

The first thing that comes to mind is sort of a pressure cooker, although that might be more steampunk rather that your time period. The idea would be to build a gigantic canon with an even bigger pressure tank below it, to give it a big chunk of speed from the start.

Doing the numbers, you only plausibly get enough energy from that to launch a capsule in the hundred-of-kilotons range to something close to Earth excape velocity, at late 1940s tech level, with an underwater nuclear detonation. (Unless I am missing an alternative which I do not think I am.)

After that, you can have some rocket contraption to maneuver it the rest of the way.

Not really plausible, alas, neither with the amount of fuel for a chemical rocket to make any significant difference to a mass that big, nor with building anything robust enough to take the stress of launch.  (particularly launch-from-seabed, which needs extra energy but is better for not covering half a continent with fallout.)

The whole thing build sort of like an artificial geyser with a giant cork on top, and then you loosen the cork so it flies pow, right to the moon.
Volcanos and mad science is always a great combination

Yes, but tying such a cork down until you build up enough pressure under it to carry so big a vehicle to escape velocity does, alas, get into magic materials tech.

[Haru]

Hmm you're probably right. Still, I kind of like the idea of using geothermal energy to fire a space ship huge rock to the moon. But I realize that was not even the integral part of your question.

Maybe the SPO can be put on the rock rather loosely and detach on entry, where it can fall down on its own little parachute. It could be attached magnetically and released on a timer or remotely. Or it is anchored with metal rods that are drilled deep into the rock and detach with small explosives. Or some other way I can't think of right now.
In that case, I don't think the container would have to be all that durable, a sturdy metal box would probably do the trick. A mini spaceship if you will, like the capsule the astronauts used to come back in, only it can possible be even smaller than that.

[LDWriter2]

This is in fact the case; the long-term plot relevance is for that information to have survived and got out in a context where it's thought to have been lost.

The problem is, finding a physically plausible means of storing rather a lot of information in a small space (even using remnant tech from higher tech levels, I want not to have to break physics here) that can readably survive the stresses of the launch and landing.

Just had an idea, I would think this depends on how the info is storied. I was trying to think of what type of data storage they had in the 40s. Computer tape, written word, audio tape, punch cards, vinyl records. They may have had some type of metal "paper". Not sure if they had cassette tapes back then or not. But as I think someone suggested your world could have some tech that is from the fifties or sixties. A little mixing of tech might be a good idea because it wouldn't be a complete parallel development.  Anyway what type of container would depend on what type of data storage. Lead lined for sure, padded probably, maybe a box or barrel completely filled so the object would not be able to bounce around. Not sure if they would have suspended the object by straps as I have seen at times. Not sure when that university started the yearly challenge to drop an egg from a great height and not have it break.  But if you could find one of the first year results on line you might find some ideas.
 
A bullet shaped container maybe with either a very hard nose or a false one that is made to break off. I can picture this one going alone with the tech they had in SF TV shows-movies from the forties. 

Maybe more than one copy, I think they believed in back-ups back then. Or find a way to connect it to the front of the ball in a way so that it would drop off just before impact. Some type of mechanical release mechanism or slow acting acid to burn through a strap. I believe they could have worked something out back then.

That's all I have for now.

[Serack]

This is in fact the case; the long-term plot relevance is for that information to have survived and got out in a context where it's thought to have been lost.

The problem is, finding a physically plausible means of storing rather a lot of information in a small space (even using remnant tech from higher tech levels, I want not to have to break physics here) that can readably survive the stresses of the launch and landing.

titanium robust punch cards.  Large amounts of punch cards were used in mechanical calculators during the Manhatan project according to Feynman's "Surely You Must be Joking Mr. Feynman"

You could even have organic (paper) ones laced through the major payload, and the recoverers discover them as stratta, and retrive the information by analyising the patterns in the residual whatsits between stratta. 

Redundancy might be key.

[the neurovore of Zur-En-Aargh]

Maybe the SPO can be put on the rock rather loosely and detach on entry, where it can fall down on its own little parachute. It could be attached magnetically and released on a timer or remotely. Or it is anchored with metal rods that are drilled deep into the rock and detach with small explosives. Or some other way I can't think of right now.
In that case, I don't think the container would have to be all that durable, a sturdy metal box would probably do the trick. A mini spaceship if you will, like the capsule the astronauts used to come back in, only it can possible be even smaller than that.

I see I didn't specify my initial problem space in enough detail; all of what you suggest makes sense as options (well, modulo that a parachute's not much use on an airless moon) except that I need to expand on what I meant by "hide" in the first post.  This is an object that has been concealed about the bullet in ways that most people involved with the project need not to have seen, and retrieved from the crash site in ways that weren't noticed by anyone until events elsewhere prompt a forensic re-examination (this latter being the bit that happens in my actual story).  I think that tends against securing the object to the outside of the bullet in some way that detaches before impact; this is a situation where somebody would have noticed that.

[the neurovore of Zur-En-Aargh]

Just had an idea, I would think this depends on how the info is storied. I was trying to think of what type of data storage they had in the 40s. Computer tape, written word, audio tape, punch cards, vinyl records. They may have had some type of metal "paper". Not sure if they had cassette tapes back then or not. But as I think someone suggested your world could have some tech that is from the fifties or sixties. A little mixing of tech might be a good idea because it wouldn't be a complete parallel development.

It's a world of people originally from Earth who have got records of Earth history to serve as guidelines, so I'm not opposed to a certain degree of following the path they are given as tech development goes; I'm thinking that they may be balked at some levels by not having a great deal of aluminium around, for example.

Lead lined for sure, padded probably, maybe a box or barrel completely filled so the object would not be able to bounce around. Not sure if they would have suspended the object by straps as I have seen at times. Not sure when that university started the yearly challenge to drop an egg from a great height and not have it break.  But if you could find one of the first year results on line you might find some ideas.

Good thought. Thank you. 

A bullet shaped container maybe with either a very hard nose or a false one that is made to break off.

It's bullet-shaped basically to minimise the amount of heat generated by friction while going up through the atmosphere of the planet during launch.  The scale of the impact with the moon isn't one where the shape of the original container will survive - the principal intent of the project is to deliver large quantities of raw metallic ores, the designers do not care whether they get melted or scattered about some or buried on landing and are much more likely to err on the side of overkill where the propulsion is concerned. 

The thing that's really balking me about the possible solutions I have come up with is that I'm not seeing any way of guaranteeing the thing won't tumble randomly in flight - fins are useless in vacuum even if I could believe in any surviving the launch, and I'm not seeing any plausible way to spin-stabilise it either.

[Serack]

The thing that's really balking me about the possible solutions I have come up with is that I'm not seeing any way of guaranteeing the thing won't tumble randomly in flight - fins are useless in vacuum even if I could believe in any surviving the launch, and I'm not seeing any plausible way to spin-stabilise it either.

Try to find a way to use tidal forces (principles similar to tidal locking and the Roche limit) to cause it to auto stabilize as it descends into the moon's Gravitational Well.

In otherwords, depending on shape and size, the difference in gravitational force seen on the portions closest to the moon could be sufficiently different from the forces seen by the portions furthest that they effect its orientation, solving the tumbling problem.

[Yeratel]

When NASA sent the Voyager probes on a trip outside our solar system, they put data about Earth and our solar system embossed on thin gold plates attached to the spacecraft.  A scroll of gold, or gold-plated alloy could hold a considerable amount of data, and be rolled up compactly inside  a heavy protective armored tube to suvive a considerable amount of impact force.
Getting many tons of cargo from an Earthlike gravity well to a nearby moon with 1940s technology is doable, if not exactly cheap.  An enlarged V2 type rocket with an extra stage, all the way up to something like an Atlas booster like the ones that sent the Apollo missions to the moon would be feasible, using hydrogen or some hydrocarbon fuel with liquid oxygen.
Launching thousands of cargo rockets is no problem in a controlled economy.  There were even plans in the late 1940s and early 1950s for using an atomic power plant to power a plasma rocket engine, but those got scrubbed because of civilian concerns about radiation damage if one ever crashed. Those concerns would be unlikely to stop a project under a totalitarian government, it would just relocate the rocket base away from population centers near the capitol.

[knnn]

The thing that's really balking me about the possible solutions I have come up with is that I'm not seeing any way of guaranteeing the thing won't tumble randomly in flight - fins are useless in vacuum even if I could believe in any surviving the launch, and I'm not seeing any plausible way to spin-stabilise it either.

Why do you need to be stabilized after it leaves the atmosphere?  Once it is in vacuum, I'd think that all you care about is that the center of mass is pointed at the moon.

Also, how complicated is the information you are trying to encode?  If it is only a few bits of information, you could store it as the ratio between the total quantities of two (unusual) elements used in the bullet.



 

[OZ]

I like what Yeratel said about the gold plates although you would probably want a harder metal to survive your giant bullet. You could stamp the information onto sheets of steel or some other hardened metal then roll the steel into tubes ( I say tubes plural because some redundancy is probably needed.). If you made the steel tubes to look part of a steering rocket or some other mechanism that was on the "bullet" no one would notice them. Say, for instance, that you had some steering rockets with minimal fuel that were only to be used in the very final stages of the bullet approaching the moon. If the rocket broke apart just as the bullet was approaching the moon's surface, no one would probably notice a few extra metal tubes amidst the exhaust tubes or support struts or whatever other part of the mechanism that the tubes were created to mimc. There would have to be some way of identifying which tubes actually contained the message. Someone who was unaware could have one of the tubes for a souveneir for years as long as they never cut it down one side and flattened it out, they would never know what they had.