an engineering problem which I need to solve for a story

[Snowleopard]

If it's coming out of China I wouldn't be surprised.
The Chinese almost destroyed the jade carving industry in their country.
All the jade carvers were sent out to do 'useful' things like farm.
It's only been in the past 10 or 20 years that they realized their mistake and began to train up
a new generation of jade carvers.  A LOT of it - is Communist propaganda stuff (what a waste of good jade)
but there are some very fine artists doing it.  So, that they'd found or got a way to make lesser quality jade
a viable thing would not surprise me at all.

[Quantus]

Not exactly what you are talking about, but close enough to be interesting:  A LunarX startup to send your DNA to the moon. 

http://www.parabolicarc.com/2012/07/06/gxlp-update-omega-envoy-launches-kickstarter-campaign/


EDIT:  Also a truly crazy idea about an theoretically possible crystal based computer that would be symetrical in 4 dimensions, allowing it to survive even the heat death of the universe...   

[Figging Mint]

Err... I don't understand.    Why can't you use a Gerald Bull-type supergun?  NOT nuclear?

And why can't you use the original bullet as a deceleration-sabot for records coded onto a kinetic penetrator?

[the neurovore of Zur-En-Aargh]

Err... I don't understand.    Why can't you use a Gerald Bull-type supergun?  NOT nuclear?

They don't really scale well to a hundred-thousand-tonne shell by my back of the envelope calculations.  (Also, the folks making this have a certain weakness for the grandiose.)

And why can't you use the original bullet as a deceleration-sabot for records coded onto a kinetic penetrator?

I'm not seeing a way of doing that that does not again fall foul of too many people knowing about it.

Basically, the existence of the hidden object has to not be deducible from the shell's design, by someone who has access to most of the records and many of the people involved, or from examination of the impact site. 

[lt_murgen]

Here is my suggestion, and it came out of the idea of solving your guidance problem as well:

The designers of the “bullet” realized they needed to be able to control the center of mass in-flight.  To do that , they designed a simple guidance mechanism.  It is a pressurized, fluid filled series of tubes criss-crossing through an open sphere.  Syspended in the fluid are small ball bearings.  A gyroscope/magnet system can make the ball baerings move/clump about the device, altering the center of mass enough to make small adjustments.

The spy could have encoded the data onto a series of ball bearings.  The system would be big enough that the bearings could be in multiple sets of the data.  Thus if one or more was damaged, the possibility of redundency still maintains data integrity.  All the spy would have to do is swap out their ball bearings for the ones in the guidance package sometime before launch.

Add in somewhere that the bearings and fluid would be put together just before launch, and put into the system just before launch, so as to avoid contamination. 

[knnn]

The designers of the “bullet” realized they needed to be able to control the center of mass in-flight.  To do that , they designed a simple guidance mechanism.  It is a pressurized, fluid filled series of tubes criss-crossing through an open sphere.  Syspended in the fluid are small ball bearings.  A gyroscope/magnet system can make the ball baerings move/clump about the device, altering the center of mass enough to make small adjustments.

Remember that no matter what you do, in a closed system the center of mass should will still end up moving in the exact same trajectory.

Thus, unless you are positing secondary explosions (blowing off chunks of the bullet), or thrusters (fast moving gas particles in a perpendicular direction), "moving around the center of mass" inside the shell will not really help change the course of the bullet.

[Figging Mint]

Basically, the existence of the hidden object has to not be deducible from the shell's design, by someone who has access to most of the records and many of the people involved, or from examination of the impact site.

Give it a logical overt reason for existence?    I mean if you're delivering resources as disparate as uranium and copper at the same time it would be somewhat logical to attempt to keep /some/ heavier resources closer to the surface, so it would be natural to attempt to randomize the energy of those heavier resources?   One way to do the randomizing might be to have collisions amongst several heavy-resource bodies within the bullet?    Essentially, the bullet turns into a dead-blow hammer? 

[Figging Mint]

They don't really scale well to a hundred-thousand-tonne shell by my back of the envelope calculations.  (Also, the folks making this have a certain weakness for the grandiose.)

Ah, 'k.   Volume vs. area bites us on the bottom /again/.

[Quantus]

With regards to the Bullet Shape, that is only actually a benefit is you expect to impart an axial spin on the slug, as the rifling inside a gun barrel would do.  It doesnt sound like you expect to have that kind of control at the launch (though it could be theoretically possible with well timed magnets or some such). 

Without that spin the bullet will inevitably start to tumble, which will hurt accuracy quite a bit even in space (rotating systems can skew the trajectory, not unlike a curve ball).  Without that spin, a sphere is far more efficient.  Specifically, a sphere with golf-ball style divets.  Believe it or not, the divets actually decrease that drag forces from the atmosphere, which increases range.  In this case that would decrease the force required to make orbit. 

[the neurovore of Zur-En-Aargh]

With regards to the Bullet Shape, that is only actually a benefit is you expect to impart an axial spin on the slug, as the rifling inside a gun barrel would do.  It doesnt sound like you expect to have that kind of control at the launch (though it could be theoretically possible with well timed magnets or some such). 

I'd been thinking roughly bullet shaped rather than sphere because of wanting fairly even impetus across the bottom of the thing for the launch - it's kind of a limit case of http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29 , really.

[Quantus]

I'd been thinking roughly bullet shaped rather than sphere because of wanting fairly even impetus across the bottom of the thing for the launch - it's kind of a limit case of http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29 , really.

Unless I am reading this wrong, that is a completely different case from what I thought you were intending.  Are you expecting to launch an innert slug from Nuclear launching platform (a gun+bullet design), or launch an actual craft with an on-board nuclear thrust system (Missiles, Orion Craft)?

If we are talking a craft with on-board systems rather than a solid slug fired from a ground-based platform, then it opens up several other avenues to explore.

[the neurovore of Zur-En-Aargh]

Unless I am reading this wrong, that is a completely different case from what I thought you were intending.  Are you expecting to launch an innert slug from Nuclear launching platform (a gun+bullet design), or launch an actual craft with an on-board nuclear thrust system (Missiles, Orion Craft)?

An inert slug; I was just using the information about pusher plates from that project as of relevance to not destroying my slug during launch.

[Quantus]

An inert slug; I was just using the information about pusher plates from that project as of relevance to not destroying my slug during launch.

OK, then the point remains.  Without maintained thrust at the rear, a slug is being carried on pure momentum, resisted by aerodynamic drag.  The turbulence effects will eventually cause it to tumble without an axial spin or some sort of air-foil geometry.  The first would just be difficult without a "barrel" of some kind, and the latter would only be worth the effort for the first part of the trip, and would complicate everything on the latter end.  Especially if we are talking about something where all the math is done by hand.  In those circumstances you typically look to simplify the math as much as possible, since the smallest variance can push your aim waaay off.

What would you think about a two-stage launch?  Like a ground-based blast to get the material into orbit (possibly in a relatively re-useable launch module, a station to catch it as it begins to fall back to earth, then a secondary blast to push it off to the moon (possibly after separating the payload from the more durable launch casing.  The data could be concealed in any number of stages, especially if there is any module separation in orbit.  And that would widen the list of materials that they could launch, since softer things like copper would behave far differently than your irons, titaniums, and tugstens.

[Figging Mint]

What would you think about a two-stage launch?  Like a ground-based blast to get the material into orbit (possibly in a relatively re-useable launch module, a station to catch it as it begins to fall back to earth, then a secondary blast to push it off to the moon (possibly after separating the payload from the more durable launch casing.  The data could be concealed in any number of stages, especially if there is any module separation in orbit.  And that would widen the list of materials that they could launch, since softer things like copper would behave far differently than your irons, titaniums, and tugstens.

I thought about that but the 'grandiose' predisposition would seem to preclude orbital assembly.

[Quantus]

I thought about that but the 'grandiose' predisposition would seem to preclude orbital assembly.

If they are aiming for a lunar base, I would think an orbital one would be a requisite first step, but I could be wrong.