Some math

[Dr Megaverse]

I'm curious if anyone knows how to compute how much damage an object falling from a height of 1,647,360ft (312m/500km) would cause upon impact. Lets assume the object is moving at a rate of 6km/sec.

I've tried to find a listing for a rule that explains falling damage per so many feet but it eludes me.

[Mack]

Short answer: It depends.
--If we're talking about an aircraft crash-landing, then try RUE p365.
--If we're talking about someone in armor / power armor falling, then try RUE p356.

You can also use RUE p183 (under Telekinesis Super) for inspiration regarding a big rock hitting someone.

[Dr Megaverse]

You can also use RUE p183 (under Telekinesis Super) for inspiration regarding a big rock hitting someone.

This is the scenario I'm looking at. I'm trying to calculate the damage a round from a Rail Gun K-Sat would cause if fired upon a target on Earth.

They orbit at 312m (500km) up, fire rounds at a speed of 6km/sec and cause 1d6X10 within their 9000 ft range (tripled for being in space).

[Prince Artemis]

Rifts New West has the rule for it under the cloud magic stuff.

[Dr Megaverse]

Rifts New West has the rule for it under the cloud magic stuff.

Did find something that mentions its 1d4md per 600ft fall. With that in mind we are looking at 2745d4 plus the initial 1d6x10. So at max damage 11,040 MD.

Right?

[glitterboy2098]

how massive is the projectile?

all you really need is the mass of the projectile, the velocity it's travelling at, the damage amount for TNT, and Robinson's First law. (anything moving at 3 Km/s delivers kinetic energy broadly equal to it's mass in TNT.)

in this case, whatever projectile the killsat fires would be equal to 2x it's mass in TNT. if you really want to get technical, if the sat sits in LEO (lets assume just outside the CODF), and doesn't de-orbit the projectile, and instead uses a terminal descent (using a rocket to intersect it's orbit with the planet at the targeted spot), you'd be looking at something more like 9km/s. minimum. the farther out the sat is, the faster it'll be going, but the harder it will be to hit accurately.

since a ton of TNT does roughly 1D6x10 M.D. as best i can figure (based on the damage of dynamite, reletive blast strength of dynamite vs tnt, and some rough figures for adjusting for larger amounts of explosive [palladium's "double the amount = 1.5x the damage" really hurts]), we just need the mass.

lets assume it's a reentry vehicle similar to the "project thor" system (100 ton tungsten rods). that seems like a fairly typical orbit to ground "Oortillery" system.
at 6km/s, you'd be looking at 2D6x1000 MD. though this would be only to a 1000 to 2000 ft 'blast' radius, since unlike a nuke or explosives, the energy is mostly directed into the ground. the "blast" would just be the pressure wave generated by the rods passage and the plasma eruption when it hits (since at those speeds, it would vaporize most of itself and a good amount of the dirt and bedrock on impact)
the 9km/s version would do more like 3D6x1000 MD, with a slightly larget 'blast' radius.
(in both cases, i'd have the full damage only at point of impact, and 1/100th the damage everywhere else. this isn't a area effect weapon. the 'blast' damage would be on par with a 1 kiloton nuke, albiet without the radiation.)

frankly, though, a 100 ton projectile would be overkill with a kinetic impactor. you can do quite well with only 1 to 10 ton "crowbars", as opposed to the 100 ton "telephone poles"

a 10 ton system would do 2D6x100 or 3D6x100 at point of impact, with a 'blast' radius of only a hundred feet or so. a 1 ton system (about as small as you could really go and still be effective) would so 4D6x10 or 6D6x10 with a blast radious of only a couple dozen feet. (personally, i'd assume 1 ton systems are the most common method of killing spacecraft...)

edit: after tracking down my notes, i found that i had misremembered my figures. corrected figures now in place.

[Mack]

Rifts New West has the rule for it under the cloud magic stuff.

Did find something that mentions its 1d4md per 600ft fall. With that in mind we are looking at 2745d4 plus the initial 1d6x10. So at max damage 11,040 MD.

Right?

Not quite. Height becomes irrelevant once the object reaches terminal velocity. What's important is it's speed, not the height.

Keep in mind that the Palladium rules weren't written for the situation you have.

[Dr Megaverse]

Rifts New West has the rule for it under the cloud magic stuff.

Keep in mind that the Palladium rules weren't written for the situation you have.

Indeed! This is part of an ongoing development of a story I'm trying to put together and it involves the use of "Oortillary" (hadn't heard this term before but LOVE it) against the CS. It was inspired by Van Buren.

I think the idea of a 1 ton rod makes a lot of sense so I'd probably go with those specs.

There is another thing I wonder, there are "Nuclear Pellet" firing K-Sats also, page 85-86ish MiO, and I'm curious if anyone might have a rough equivalency. I realize we're below board here I'm just curious for curiosity's sake.

[dragonfett]

As Mack had said, damage has more to do with speed than height. True, the higher something is dropped from, the faster it will go, but only up to a certain point. The human body can reach its terminal velocity in 500', although one could change their aerodynamics (straitening themselves to be more arrow like), they could increase their terminal velocity. Likewise, by changing the shape of the object to be more aerodynamics will allow it to go faster. That being said, because it is being shot instead of falling naturally, it probably won't do a whole lot more damage than its stated damage.

[azazel1024]

With a super aerodynamic osmium or iridium projectile you are still probably going to reach a terminal velocity in the 1-2km/sec range. That is still stupid fast when something lands on you, but it isn't leave a giant crater on the ground fast.

Of course something suitably streamlined and with a high density, de-orbited is going to smack the ground really, REALLY fast as it won't have lost a whole heck of a lot of kinetic energy passing through the atmosphere. That will cause a big stinking crater, especially if you have a good sized projectile.
-Matt

[Dr Megaverse]

So the mass of the object is what I should be concerned about. In that case let's say it's an aerodynamic slug at least 50tons heavy.

Anyone have a formula I can use to just plug in different masses, distances, etc?

[sasha]

You could go with glitterboy2098's:

a 10 ton system would do 4D6x100 or 6D6x100 at point of impact, with a 'blast' radius of only a hundred feet or so. a 1 ton system (about as small as you could really go and still be effective) would so 4D6x10 or 6D6x10 with a blast radious of only a couple dozen feet. (personally, i'd assume 1 ton systems are the most common method of killing spacecraft...)

[azazel1024]

So the mass of the object is what I should be concerned about. In that case let's say it's an aerodynamic slug at least 50tons heavy.

Anyone have a formula I can use to just plug in different masses, distances, etc?

Density, not mass.

The mass of the object is relatively irrelevant. A 50t tank isn't going to reach obscenely high terminal velocities, but a 1 ounce lead sinker would reach pretty high terminal velocities.

How aerodynamic an object is, combined with its density are what cause a high terminal velocity. The upper limit isn't much above supersonic in the lower levels of the atmosphere.
-Matt

[Dr Megaverse]

So once an object reaches terminal velocity it's mass doesn't change the amount of force upon impact? That seems to be what I'm reading which...doesn't make sense.

I would think the higher the mass of the projectile the greater the amount of force it can translate to it's target....at a certain speed of course.

[dragonfett]

It's mass already has changed the amount of force on impact by the terminal velocity.

[azazel1024]

The mass does matter for the amount of energy it delivers on impact, but the mass has no bearing on what the terminal velocity will be, that is soley dependent on the objects aerodynamics and density.

The most dense subject know is a toss-up between Iridium and Osmium, so you can't get any more dense than that, you can only improve the aerodyanamics.
-Matt

[Shark_Force]

well, we've got all kinds of crazy super-science. if you could form a solid material of nothing but neutrons (commonly referred to as 'neutronium' in science fiction)that would theoretically be extremely dense, would it not? (note: there isn't really any particularly good scientific indication that this would be legitimately possible that i can find, but then again, this is rifts; if we only used stuff that was scientifically plausible, things would look rather different)

[azazel1024]

That's why I was saying known, or maybe I should have said accesible in non-fiction.

There are degrenerate forms of matter that are much denser, but they are also not really feasibly materials to use, even assuming they'd retain their degenerate form when not under crushing gravity.

Sure you could make electron degenerate bullets, but then you are either firing a 20t 9mm bullet with the recoil of an Iowa class battleship's broadside, or you are firing bullet the size of a grain of sand, that still weighs a couple of hundred pounds. Sure it'll penetrate like crazy, but it is going to make an itty bitty hole through the person you hit, and the 5 buildings behind it before it stops. Not very effective. You need some lower limit of surface area of a projectile for it to be effective at causing disabling damage to whatever it hits.
-Matt

[Shark_Force]

That's why I was saying known, or maybe I should have said accesible in non-fiction.

There are degrenerate forms of matter that are much denser, but they are also not really feasibly materials to use, even assuming they'd retain their degenerate form when not under crushing gravity.

Sure you could make electron degenerate bullets, but then you are either firing a 20t 9mm bullet with the recoil of an Iowa class battleship's broadside, or you are firing bullet the size of a grain of sand, that still weighs a couple of hundred pounds. Sure it'll penetrate like crazy, but it is going to make an itty bitty hole through the person you hit, and the 5 buildings behind it before it stops. Not very effective. You need some lower limit of surface area of a projectile for it to be effective at causing disabling damage to whatever it hits.
-Matt

recoil is typically not much of a concern when you're dropping an object from orbit.

[sasha]

Depends on the mass you're dropping, I suppose.

[azazel1024]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

[dragonfett]

Not to mention you need to make sure that the object has sufficient speed to break into the atmosphere.

[Colt47]

Would the buoyancy force even have a noticeable effect on a 50 metric ton slug being fired at mach 20 or higher from space? Also, don't even bother to bring in aerodynamics as an excuse for lowering the force from the shot by any significant portion. I think we can all assume that by the year 2098 people didn't get any stupider and decided we should start firing cubes out of oddly shaped barrels. The Air drag coefficient on a streamlined object is approximately 0.04 and at the speeds this thing would be getting fired at... yeah. Honestly the damage from the gun really shouldn't change much upon entering the atmosphere. Just don't try to hit something the size of a person from space with a 50 ton slug. Not only is it a waste of ammo, but it is terribly embarrassing.

[dragonfett]

All I was trying to say was that simply dropping it would not let it break into the atmosphere.

[sasha]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

Mass is a term in the force equation. And momentum is conserved.

[Rallan]

Wait. Rifts has consistent rules for how much MDC an item of X density with Y mass at Z velocity will do?

[azazel1024]

A lot of people seem to not be understanding what terminal velocity is or how air resistance works.

An object simply dropped will have a certain terminal velocity. The terminal velocity is derived by the velocity at which the force from air drag is equal to the force of gravity on the object.

The force from air drag is

F = Cd*V*A

Force = Coefficient of drag * Velocity * Frontal surface Area

The force of gravity is
F = Mg

Force = mass * gravity, in this case close enough to 9.8 to call it that, even in LEO.

The only way to increase the terminal velocity is to change the coefficient of drag (making it more aerodynamic) which can only be done up to a certain point of increase the density of the object.

If you increase the mass while keeping the density the same, you either increase the coefficient of drag (by making the dropped object longer, which negatively impacts Cd at a certain point), and or increase the frontal cross section, keeping the terminal velocity the same. If you increase the density you can increase the mass while keeping the coefficient of drag the same and the frontal cross section the same.

So making something more massive will NOT increase the terminal velocity.

However, a more massive object dropped at a velocity in excess of the terminal velocity will better maintain its momentum on its way to the ground (something in orbit has an initial velocity that is fairly high). Density will also help in this manner (by keeping a high momentum, whilst reducing drag).

So a 50ton golf ball dropped from from above the Earth with zero velocity initially is going to reach the same terminal velocity as a 5 gram golf ball. One deorbited, the 50 ton golf ball is going to retain more of its initial velocity, assuming that drag wouldn't have been enough to reduce it to terminal velocity, than the 5 gram golf ball.
-Matt

[azazel1024]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

Mass is a term in the force equation. And momentum is conserved.

Certainly, but if you are going to impart a resonable amount of force to deorbit a neutron degenerate BB weighing 20 tons, you are going to need a decent sized rocket to do this with...and you are going to have to come up with a creative way to attach something the size of a BB to something probably the size of a van.

One issue with kinetic strikes from orbit is that it takes some pretty darned fancy math to figure out exactly where they will hit, at least with enough precision to land something the size of a crowbar on up to a semi-truck on something the size of a bunker, building or enemy position.

Within reason the higher the delta V from the deorbiting burn or shot, the easier it is to get better accuracy so you deorbit quickly, instead of after a few dozen orbits and skimming velocity off the atmosphere before it causes reentry (and you want a somewhat vertical strike as well, an impact that is highly angled is likely just to bounce of something well hardened).
-Matt

[glitterboy2098]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

you don't need to fire it or mount big rockets. it's in orbit. which means it's already moving at 9 kilometers a second. so all you have to do if fire a few small thrusters (not very powerful, in fact they'd probably not be able to blow away a sheet of paper if it were in the atmosphere, but space has no friction, and small changes in velocity over time quickly alter directions*), which would alter the orbit of the object until it's orbital path (its 'course') passes through the planet. where the orbital path and the surface meet is the point of impact. once in the atmosphere, small vanes and panels would allow it to change course due to drag.

since the weapon relies on the energy of mass hitting at high speed, and has no explosives involved, the mass of the engines, panels, computer guidance, etc is already included in the projectile mass. anything over the mass of those components is basically just metal added to make it mass more.


*the Space Shuttle was 150 tons, and it deorbited using small chemical rockets (the OMS, or orbiter manuvering system), that put out only 6000 pounds of thrust at full burn. that's an accelleration of 2 feet per second per second, or about 0.06 gravities. it could put the shuttle onto a ballistic return (basically the same kind of thing we're talking about for this weapon. a reentry where the object doesn't use any thrust to slow down, just passes through the atmosphere. for the shuttle, the goal is a controlled sheeding of speed using airbraking through the atmosphere at a shallow angle, while for the weapon, your looking at a design to keep as much speed as possible and pass through at a steep angle, so you have high velocity when you do your destructive Lithobraking (IE: hit the ground))

[Colt47]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

Mass is a term in the force equation. And momentum is conserved.

Certainly, but if you are going to impart a resonable amount of force to deorbit a neutron degenerate BB weighing 20 tons, you are going to need a decent sized rocket to do this with...and you are going to have to come up with a creative way to attach something the size of a BB to something probably the size of a van.

One issue with kinetic strikes from orbit is that it takes some pretty darned fancy math to figure out exactly where they will hit, at least with enough precision to land something the size of a crowbar on up to a semi-truck on something the size of a bunker, building or enemy position.

Within reason the higher the delta V from the deorbiting burn or shot, the easier it is to get better accuracy so you deorbit quickly, instead of after a few dozen orbits and skimming velocity off the atmosphere before it causes reentry (and you want a somewhat vertical strike as well, an impact that is highly angled is likely just to bounce of something well hardened).
-Matt

Azazel, I think it is safe to assume that if someone put a giant coil gun in space and designed it to fire 20-50 ton aerodynamic rounds towards the earth it will have the necessary systems to compensate for recoil.

[azazel1024]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

you don't need to fire it or mount big rockets. it's in orbit. which means it's already moving at 9 kilometers a second. so all you have to do if fire a few small thrusters (not very powerful, in fact they'd probably not be able to blow away a sheet of paper if it were in the atmosphere, but space has no friction, and small changes in velocity over time quickly alter directions*), which would alter the orbit of the object until it's orbital path (its 'course') passes through the planet. where the orbital path and the surface meet is the point of impact. once in the atmosphere, small vanes and panels would allow it to change course due to drag.

since the weapon relies on the energy of mass hitting at high speed, and has no explosives involved, the mass of the engines, panels, computer guidance, etc is already included in the projectile mass. anything over the mass of those components is basically just metal added to make it mass more.


*the Space Shuttle was 150 tons, and it deorbited using small chemical rockets (the OMS, or orbiter manuvering system), that put out only 6000 pounds of thrust at full burn. that's an accelleration of 2 feet per second per second, or about 0.06 gravities. it could put the shuttle onto a ballistic return (basically the same kind of thing we're talking about for this weapon. a reentry where the object doesn't use any thrust to slow down, just passes through the atmosphere. for the shuttle, the goal is a controlled sheeding of speed using airbraking through the atmosphere at a shallow angle, while for the weapon, your looking at a design to keep as much speed as possible and pass through at a steep angle, so you have high velocity when you do your destructive Lithobraking (IE: hit the ground))

Hmm, not something I had been thinking of. I had been thinking along the lines of a dumb projectile, not a smart projectile. Okay, I see where you went with that. Put some aerodynamic surfaces on it and a guidance system and you could deorbit it with very low thrust and and possibly still achieve a relatively steep descent. I think you'd end up sheding quite a bit of velocity in the end though, but I'd bet you'd still keep a good precentage of your original momentum. Hitting at 2-3km/sec is still going to make you noticed in the catastrophic destruction kind of way.
-Matt

[azazel1024]

Depends on the mass you're dropping, I suppose.

And how you are dropping it. Just letting going of something isn't going to do a darned thing. If you are firing it down out of orbit it'll have recoil. If you are using some kind of attached thrusters or rockets...well you are attaching some big old rockets/thrusters to an itty bitty tiny little thing.
-Matt

Mass is a term in the force equation. And momentum is conserved.

Certainly, but if you are going to impart a resonable amount of force to deorbit a neutron degenerate BB weighing 20 tons, you are going to need a decent sized rocket to do this with...and you are going to have to come up with a creative way to attach something the size of a BB to something probably the size of a van.

One issue with kinetic strikes from orbit is that it takes some pretty darned fancy math to figure out exactly where they will hit, at least with enough precision to land something the size of a crowbar on up to a semi-truck on something the size of a bunker, building or enemy position.

Within reason the higher the delta V from the deorbiting burn or shot, the easier it is to get better accuracy so you deorbit quickly, instead of after a few dozen orbits and skimming velocity off the atmosphere before it causes reentry (and you want a somewhat vertical strike as well, an impact that is highly angled is likely just to bounce of something well hardened).
-Matt

Azazel, I think it is safe to assume that if someone put a giant coil gun in space and designed it to fire 20-50 ton aerodynamic rounds towards the earth it will have the necessary systems to compensate for recoil.

Point being it is very improbable you could compensate for the recoil...so you couldn't put a giant coil gun in space that fire a 20-50t round at Earth. Not unless you want to be designing multikilo ton sattelites. Not unless you are just nudging lose the projectile with the coil gun. Not something you could, say, impart a few thousand M/sec of delta V to.
-Matt

[Shark_Force]

yeah, if i was going to actually be shooting stuff, i'd say the location of choice would be the moon probably. either that or haul an asteroid nearby or something.

but just dropping stuff from orbit? not a huge problem there.

(also, on a side note, if you can't get the super-dense material to solidify, you could also theoretically contain it in something else. while the kind of pressure in a neutron star is doubtless pretty hard to achieve, that doesn't mean it can't be done via the special powers of handwavium)

[azazel1024]

yeah, if i was going to actually be shooting stuff, i'd say the location of choice would be the moon probably. either that or haul an asteroid nearby or something.

but just dropping stuff from orbit? not a huge problem there.

(also, on a side note, if you can't get the super-dense material to solidify, you could also theoretically contain it in something else. while the kind of pressure in a neutron star is doubtless pretty hard to achieve, that doesn't mean it can't be done via the special powers of handwavium)

Well, I didn't realize we had gone to handwavium. Anything is possible then.
-Matt

[Shark_Force]

yeah, if i was going to actually be shooting stuff, i'd say the location of choice would be the moon probably. either that or haul an asteroid nearby or something.

but just dropping stuff from orbit? not a huge problem there.

(also, on a side note, if you can't get the super-dense material to solidify, you could also theoretically contain it in something else. while the kind of pressure in a neutron star is doubtless pretty hard to achieve, that doesn't mean it can't be done via the special powers of handwavium)

Well, I didn't realize we had gone to handwavium. Anything is possible then.
-Matt

most of the official rifts rules are based on handwavium as far as i can tell.

[glitterboy2098]

Wait. Rifts has consistent rules for how much MDC an item of X density with Y mass at Z velocity will do?

not officially.

this is a mashup of an official rule (double the explosive produces only 1.5x the damage), and two real world guidlines (Reletive Effectiveness Factor, which is used to compare different explosives, and Robinson's First law, which is "something hitting at 3 km/sec (kips) delivers kinetic energy broadly equal to its mass in TNT.")

using these combinations, it is possible to figure out how much damage (roughly) a large mass can do when moving at 3kps or more. (3kps = roughly 10 mach)

Dynamite does 1D6x10 SD per kilogram (usually listed as 5D6 sd per pound..kilograms are easier to work with, as you'll see in a second.)

tnt is roughly twice the RE factor of Dynamite (1, vs. .4 to .8 rounded to.5 for our purposes , see the chart here)

so the damage would be:
2 kilograms = 3 dice
4 kilograms = 4.5 dice
8 kilograms = 6.75 dice
16 kilograms = 10.125 dice
32 kilograms = 15.187 dice
64 kilograms = 22.78 dice
128 kilograms = 34.17 dice
258 kilograms = 51.257 dice
512 kilograms = 76.88 dice
1024 kilograms = 115.3 dice

so at 1024 kilograms (a touch over one ton), the damage would be 115.2 x 1D6x10 S.D. or a maximum of 6918 S.D.
which i derived down to 1D6x1000 (1D6x10 M.D.), since the extra 900 S.D. (or 9 M.D.) wasn't enough to bump it up another dice type.


since we can figure out what 3 kilometers a second in palladium mach #'s (670mph/1072km/h):
3km/s = 10,800km/h (3x60x60)
10,800/1072 = 10.075

so when moving at mach 10, one ton of matter would do 1D6x10 M.D. from just straight kinetic energy. note this doesn't include factors like density, or penetrator design, and so on. it's just a figure to find the rough damage from smacking a given mass of 'stuff' into another.

i also tend to ignore the "double the amount only equals 1.5x the damage" past this point, since not only does that make it really hard ot figure damage from multiple tons and multiples of 3km/s at the same time, it grossly penalizes the really massive kinetic impacts, when there are weapons using a tiny fraction of a ton and can do similar damage. for example, the glitterboy's boom gun fires a only a couple of kilograms of metal, at only 1.5km/s, but does 3D6x10 M.D. in damage, or roughly equivilent to a strike with a 1 ton object at orbital speeds. so by using 'accurate' math to figure the damage, we find ourselves with the bizzare situation of orbital bombardments by kinetic impactors being less of an example of 'power creep' than canon ground based weapons...

[azazel1024]

yeah, if i was going to actually be shooting stuff, i'd say the location of choice would be the moon probably. either that or haul an asteroid nearby or something.

but just dropping stuff from orbit? not a huge problem there.

(also, on a side note, if you can't get the super-dense material to solidify, you could also theoretically contain it in something else. while the kind of pressure in a neutron star is doubtless pretty hard to achieve, that doesn't mean it can't be done via the special powers of handwavium)

Well, I didn't realize we had gone to handwavium. Anything is possible then.
-Matt

most of the official rifts rules are based on handwavium as far as i can tell.

Sorry, my semisarcasm didn't come across. Most of PB is handwavium, which is not necessarily a bad thing. Though a bit of consistancy in the handwavium would be nice.
-Matt

[Dr Megaverse]

Interesting discussion folks! The 1d6x1000 figure was sort of what I was looking for. Although I did learn some new things about orbital re-entry I hadn't thought about! Thanks guys!