
-------- TML Message #1787 --------

Archive-Message-Number: 1787
Date: Thu, 15 Nov 90 16:02:41 -0500
From: "T. L. Hayes" <al646@cleveland.freenet.edu>
Subject: Bad News from the Physics Frontier!



BAD NEWS!!!

     Earlier I posted a "if it ain't broke don't fix it" warning.  This is
a "if you can't fix it leave it alone" warning.  During lunch today I took
to playing with some numbers.  From an earlier post I got some figures for
a scout/courier (I don't have books at work so I have to trust these numbers)
that said:

     Displacement - 100 tons
     Unload Mass  - 1084.0707 tons
     Acceleration - 2G

     Now the amount of energy obtained from the fusion of 1 ton of hydrogen
into helium is 2.58 E6 Joules (roughly).  This assumes all the mass 
difference between 4 hydrogen and 1 helium is converted to energy.  Since
this is not true, the actual energy output will be lower.  

     A scout ship accelerating at 1G for 1 hour will cover a distance of
63568.8 km and be travelling at a speed of 35.3 km/s or 127,137.6 km/hr.
The amount of energy consumed during the hour will be 6.76 E14 Joules just
to propel the ship.  This is equivelant to 2.62 E8 tons of hydrogen!

     Clearly manuever drives are going to violate physics or they will not
work.  Notice this makes no assumptions about how you move the ship the only
assumptions made are its mass and acceleration and that it starts from rest.
Energy must be conserved.

ANOTHER TOPIC

     I read in (1766) black globes by Paul Baughman -

Why can't it maneuver?  With reactionless thrusters which don't emit anything
to be absorbed by the field, you should be able to maneuver all you want.  Of
course, you can't *SEE* where you are going, and running into an asteroid
(after you drop the field) could ruin your day, but what is the handwaving-
pseudo-technical explanation for why you can't maneuver?

END OF EXERPT -

Correction - you emit energy.  In order for the ship to move it MUST exchange
energy with the "rest of the universe" which it can not do while in a
Black Globe.  Reactionless (imho) means that it does not generate the force
by expelling matter out the exhaust.

     The deeper I look into Traveller's physical problems (prompted in
part by all the talk on the lists) the more I find that many of the places
that violate physics do so because its more intertaining and playable (and
more like the movies and books we've all read).  Places I've seen that may
not be fixable include Jump Drive, Maneuver drives, Anti-Gravity, repulsor
or tractor beams, and nuclear dampers.  Some of these can be talked around
using pseudo-physics and handwaving at least to the point that they're not
glaring problems.

     Then there are the places where the physics is easy enough to fix but
do we really want to.  An example of this kind of problem is the travel
times between planets in a single star system.  The problem is these
calculation assume you go straight from planet A to planet B accelerating
half way, decelerating the other half.  Aside from being EXTREMELY energy
inefficient, this is not possible.  All movement will be effected by the
gravity of the two planets and the sun(s) forcing the craft to fly some
sort of hyperbolic (or parabolic) path at least near the planets.  You
simply can not "warp out of orbit" in a straight line no matter how much
thrust you ship has let alone with merely 1 - 6 G's.  Now we can fix this
but the travel times may become unacceptably long and, even though this
is a violation of the laws of physics, it doesn't really impact on the
game (that is it doesn't NEED to impact on the game).

     It bothers me when games ignore physical laws blatantly but I am coming
to see that it is often neccessary if we are to have the games reflect
the kind of science fiction movie/book settings we've come to expect.
Interstellar travel and trade, huge fleets battling for control of the
empire, robots, technical wonders, and heros and heroines fighting for
noble causes (or greed).

I hope this didn't spoil your day!

TLH

- - --
T.L.Hayes                  |
MIT/Lincoln Laboratory     |
Lexington, MA              |

-------- TML Message #1788 --------

Archive-Message-Number: 1788
From: "Mark F. Cook" <markc@hpcvss.cv.hp.COM>
Subject: Weapon repair & Gauss recoil
Date: Thu, 15 Nov 90 13:15:00 PST

In TML Subject 1761, Bertil Jonell (d9bertil@tek.chalmers.se> writes:

> > From: Adrian Hurt <adrian@cs.heriot-watt.ac.uk>
> > Subject: (1752) Weapon repairs
> >
> > "Mark F. Cook" <markc@hpcvss.cv.hp.COM> writes:
> > >        I'd say that a specific weapons skill includes being able to
> > > fieldstrip and clean your weapon, AND THAT'S ALL.  If a component is
> > > broken, you take the weapon to a 'gunsmith' or, if you're in the service,
> > > you have the company quartermaster replace it.
> >
> > Making new parts from a piece of metal comes under Mechanical skill.
> > Again, the difficulty level depends on the component, but will probably
> > be quite high - we're talking about precision machinery here.
> 
>   But remember that even if a weapons is damage so that it won't work, that
> dosen't nessesarily mean that any part is broken.
>   Example: The magasine of an automatic weapon don't need to be bent much
> before this starts to interfer with the feed. If the top part of a magasine
> is damaged in a certain way, the weapon with refuse to fire at all. Similarly,
> springs might bent out of shape, cartridges might get stuck and so on.
>   These isn't 'Superficial' errors, because each one will make the weapon
> unusable, and 'superficial' damage won't interfear with the operation of
> something. Yet none of them require any new parts to fix, just some tools
> and a little time.

All very true.  But the last sentence really should end with "...just some
tools, a little time, and the NECCESSARY SKILLS."  In this I think the point
that Adrian makes is correct: without Mechanical-1 or better, you probably
shouldn't be allowed to do it unpenalized.  Trying to bent a caved-in clip
or a bent leaf-spring back into shape (the CORRECT shape) is a difficult
task, as anyone who has tried can tell you.  On the other hand, clearing
a jammed cartridge does not typically constitute "repairing damage" in the
MT sense, since it takes no special talent other than the ability to operate
the weapon.  you might want to treat a cartridge jam as "superficial damage",
a bent clip as "minor damage", a broken trigger or firing-pin as "major
damage", and a bent barrel/crushed receiver as "destroyed".

>   Lastly I'm going to challenge one of basic pre-conceptions of Traveller and
> MegaTraveller: The recoilless gauss-rifle.
>   The gaussrifle fires a small 4mm calibre bullet. This bullet travels at
> 1000m/s which is about as fast as an normal 5.56 NATO round. And yet, the
> gaussrifle inflict 4D with a penetration of 7, while a 5.56 NATO in Traveller
> would inflict 3D at around 3 or 4 in penetration.
>   This would indicate that the bullet from a gaussrifle travels much faster
> than a normal rifle bullet, maybe somewhere in the range of 1500 to 2000 m/s.

In fact, the Imperial Encyclopedia does list the velocity as 1500 m/s.

>   How this weapon can be thought as being particularly recoilless is beyond
> me:)

MT does NOT list gauss weapons as being "recoilless".  They list them as
being "low recoil", which is appropriate.  If you consider both F=ma and
Newton's 3rd Law ("Equal and opposite reaction") then the amount of enery
delivered to each gauss needle (and thus acceleration, since the needle's
mass is constant) is equal to the amount of recoil energy delivered to
the gauss weapon firing the needle.  Since the weapon outweighs the needle
by several orders of magnitude (4 gm. vs. 3.5 Kg., in the case of a gauss
rifle), the recoil of the weapon is going to be virtually zip.

End of story.

                "Good afternoon, boys."
                        [ "What's THAT?"
                          "Oh that, it's just the computer.  I discovered
                           it had an emergency, back-up personality, which
                           I thought might be marginally preferable." ]
                "Now, this is going to be your first day on a strange
                 planet, so I want you all wrapped up, snug and warm,
                 and no playing with any naughty, bug-eyed monsters."
                        [ "I'm sorry.  I think we might have been better
                           off with a slide-rule." ]
                "RIGHT!  Who said that?"
                        [ "Will you open up the exit hatch, please?" ]
                "Not until whoever said that owns up!"
                        [ "Oh, God!" ]
                "Come on!"
                        [ "Computer!" ]
                "I'm waiting.  I can wait all day, if neccessary."
                        [ "Computer, if you don't open that exit hatch
                           this moment, I shall go straight to your major
                           data banks with a very large axe, and give
                           you reprogramming you'll never forget, is
                           that clear?" ]
                "... I can see this relationship is something we're ALL
                 going to have to work at."
                                - Ford and Zaphon have a go-around with
                                  Eddie's 'replacement'.

        Mark F. Cook

USMail: User Interface Technical Support
        Hewlett-Packard - Interface Technology Operation
        1000 NE Circle Blvd.  Corvallis, OR 97330

INTERNET: markc@hpcvss.cv.hp.com
          markc%hpcvss.cv.hp.com@relay.hp.com

-------- TML Message #1789 --------

Archive-Message-Number: 1789
Date: Fri, 16 Nov 90 12:44:05 GMT
From: grue@batserver.cs.uq.oz.au
Subject: TDR Starships

hiya,
	My first proposal: let meson screens give an effective armour factor
against incoming meson weapons rather than simply stopping some of the
incoming fire dead.

	I don't really understand the physics involved, but the way I
understand the Starship Operator's Manual and the Refs Guide, meson
screens are supposed to slow down the incoming meson packet and make
it detonate outside the ship.  Hopefully every incoming meson packet
will be slowed down, which means that the fire will no longer hit the
delicate central parts of the ship.  Instead the fire will hit the
more robust outer sections.

	Sure, if you slow the packet down enough it won't hit you at all.
Unfortunately, large spinal mounts have a nasty tendancy to cut through
meson screens without showing any ill effects.  I don't really see any
ratonal for having a hit or miss result.  Using the screen as armour means
that every incoming meson weapon will be effected.

	Anybody like to comment about this idea?  If there are any real
complaints I'll retract the idea.


	Someone mentioned synchronising your fire with the flicker of
your black globe.  I like this idea also.  The current rules give a lot
'evidence' that the weapons fire in discreet lumps.  (meson packets are
mentions, missiles are entities, pulse lasers are too, Fusion/Plasma guns
would most likely fire shots.  PA's fire bursts also.  Beam lasers most
probably wouldn't).  Why not allow firing while the globe is flickered
off?  Other starships wouldn't be able to detect your turning off your globe
to let a battery of missiles out (the distances involved are large, I don't
have my ref's guide here but the distances involved are quite sizable even
at the speed of light) --- they are simply too far away to react before you
turn your globe back on.  Since globes are experimental at TL15 (whatever
that really means), it could be dis-allowed until TL16 which means the game
will not be alter much (who runs campaings over TL15????).

	And finally, some random ramblings about how I think TDR should come
out.....

	I think that a complete re-write is totally out of the question.  It
would be too big a task to do in our spare time.  I'd prefer to see an
evolution of the current rules into something that contains more internal
consistancy (and a better basis in real physics).  This would mean that,
we don't just throw something out because it seems silly.  We'd have to
either alter the definition a little to make that thing possible or throw
the thing out and replace it with something plausable.  (the reactionless
drive makes a nice example of both choices:  throw it out and replace it
with a reaction based drive or try to find some justification for it, i.e.
find something for it to push against).

	For starships (one of my pet areas :-), I'd like to see some
intermediate values put into the tables.  There is no reason for a spinal
meson gun-A to be as inefficient at TL15 ass it is at TL12!  It would
probably be possible to build a real working meson gun given current
technology (I think they are actually used to burn cancerous stuff out
of people), it would not be practable to do so.  The communication gear
has a nice set of intermediate values (even if they are a bit simplistic),
why not everything else???? [ the answer is that it would make for too many
extra tables ]



							Pauli
seeya

Paul Dale               | Internet/CSnet:            grue@batserver.cs.uq.oz.au
Dept of Computer Science| Bitnet:       grue%batserver.cs.uq.oz.au@uunet.uu.net
Uni of Qld              | JANET:           grue%batserver.cs.uq.oz.au@uk.ac.ukc
Australia, 4072         | EAN:                          grue@batserver.cs.uq.oz
                        | UUCP:           uunet!munnari!batserver.cs.uq.oz!grue
f4e6g4Qh4++             | JUNET:                     grue@batserver.cs.uq.oz.au

-------- TML Message #1790 --------

Archive-Message-Number: 1790
Date:     Thu, 15 Nov 90 23:10:29 PST
From: Orcinus orca <jokim@jarthur.claremont.edu>
Subject:  Re: Bad News from the Physics Frontier

Hold on, no offense but you're acting like a physicist :-).
Your figure for the amount of energy from fusing 1 ton of
hydrogen into helium is about 2.6 MegaJoules.  Now, an
engineer :-) would look at that and say "We currently have
power plants that put out thousands of Megawatts, and they
certainly aren't fusing thousands of tons of hydrogen every
second.  I must have goofed."

I double checked and got:

Hydrogen: 1.00794 grams/mole    Helium 4.0026 grams/mole

4 H  -  1 He  =  0.02916 grams/mole of matter converted to energy

1 ton of Hydrogen is 992122.547 moles so there are

(992122.547 moles * 0.02916 grams/mole) = 28930.3 grams of
matter converted to energy.  Or 28.93kg since I hate cgs :-).

Use E= m * c^2 to get

E = (28.93 kg) * (3.0 x 10^11 m/s)^2 = 2.60 * 10^24 Joules

Your figure for the energy consumed by a scout ship accelerating 
at 1G for 1 hour, 6.76 E 14 Joules, is correct.

So using the new figure for energy from fusing, this scout ship
will have consumed

[ 6.76 E14 Joules  /  ( 2.60 E24 Joules/ton of H fused)] =
        = 2.6 E-10 tons 

or 260 micrograms of Hydrogen fused.  I think we have the 
reverse problem!  This process is too efficient!  To burn
(how much does a scout ship hold?) 20(?) tons of hydrogen
in 4 weeks of constant use, we'd have to operate at, oh...
0.0000002% efficiency (within a couple orders of magnitude)
==
John H. Kim
jokim@jarthur.claremont.edu
uunet!jarthur!jokim

-------- TML Message #1791 --------

Archive-Message-Number: 1791
From: Amos Shapira <amoss%batata.huji.ac.il@cunyvm.cuny.edu>
Date: Fri, 16 Nov 90 08:37:42 -0200
Subject: Weapon repair and operation.


Hello,

	Sorry to barge in late on the discussion, I am fighting the dark
forces for a proper account.

	In any case, Operating a weapon should be considered a class skill.
That is -

		If you know how to operate a single weapon in a class, then
		you can operate ALL STANDARD weapons in this class with
		reduced efficiency UNTIL FAMILIARIZATION. After a given
		period of time has passed (and the new weapon/weapons were
		in use) the skill is acquired fully.


	Fixing a weapon is a problematic affair. Of course, machining firing
pins and slides is quite beyond anyone lacking a Mechanical-x and AT LEAST
one level of (Mettalurgy - in parenthesis, I don't think MT has one). BUT!,
identifying what is wrong is quite simple - a complete stripping shows that,
and replacing simple parts is very quick - firing pins, springs, barrels,
slides, etc.

Marc A. Volovic (accountless).

via

Amos SHapira

-------- TML Message #1792 --------

Archive-Message-Number: 1792
From: "Brent L. Woods" <woodsb@zoo.ecn.purdue.edu>
Subject: Re: (1782) Re: Black Globes
Date: Fri, 16 Nov 90 3:17:42 EST


 In message 1782, adrian@cs.heriot-watt.ac.uk (Adrian Hurt) writes:
 >
 >"Brent L. Woods" <woodsb@zoo.ecn.purdue.edu> writes:
 >>      One small quibble.  "Prototype" isn't the best word to use.  I
 >> think that "copy" would be more accurate.  The device wasn't developed
 >> by Imperial (or any other contemporary) technology.  To quote from page
 >> 31 of _High Guard_:
 >> 
 >>           "Black globe generators are not available commercially; they
 >>      are recovered artifacts installed on a makeshift basis or
 >>      experimental versions installed on tech level 15 Imperial
 >>      warships."
 >
 >" ... or experimental versions ..."
 >Sounds like prototypes to me.  Besides, in due time the Imperials should
 >learn how to copy the things.  And one or two places are now TL 16, and
 >should be capable of designing them.  The Darrians probably have a few
 >hidden away somewhere; and two Vargr worlds are TL 16, according to the
 >old Vargr Alien Module.

     Oh, certainly.  I just generally associate the word "prototype"
with "newly-developed experimental device."  If you are copying some
pre-existing thing, it'd call that an "experimental copy."

     If the device is something that *you* developed (including the
theory behind it), then I'd assume a better understanding of the
device on the part of the developers.

     Personally, I'd rather have one of the recovered Ancient artifacts
rather than a new-made copy (though I *think* that there were only
2,000 of those that were found).  I'd tend to distrust the understanding
of the copiers.

 >>      Also, the behavior of the field is fairly well known--it won't
 >> explode or "move to a different universe."
 >
 >This depends on how the PC's get hold of it.  (Assuming that they do, of
 >course - and assuming that they role-play properly, and don't make use of
 >what the players read in various manuals.)  If they got one by looting an
 >Imperial warship, they are probably more powerful than they have any right
 >to be, but can probably interrogate someone from the ship.  If they got one

     Unless it's a derelict.  As I recall, there is mention of several
black globe-equipped drelict ships here and there in the official
publications.  Like the _Kinunir_, for example.

 >the same way as the Navy did, by looting an Ancient base, and if the Navy
 >hasn't been publishing documents about black globes, then the PC's  will
 >not know what they have, or what it does.

     No, but if they feed the correct power into it, it'll turn on
(possibly damaging the surround).  If they don't, then it *should* do
nothing (I admit, *if* Grandfather used proper fail-safe design
philosophy).

 >>           "If a ship absorbs enough energy to make a jump, and is
 >>      supplied with sufficient fuel, it may jump at the end of the turn."
 >> 
 >>      Of course, this can be dangerous.  If you overload your capacitors,
 >> your ship is destroyed (by violently exploding capacitors, I guess).  I
 >> imagine that it's not a very good idea if you only have your jump drive
 >> capacitors available.
 >
 >I don't see the danger.  If the ship has absorbed enough energy to make the
 >jump, it absorbed the energy into the jump capacitors.  If it still exists,
 >it hasn't overloaded the capacitors.  There should be no risk of overload
 >due to trying to jump - either the capacitors are sufficiently charged for
 >the jump, leave them alone; or they need a little more charge, give it to
 >them.

     Ah, but what if your jump capacitors are fully charged, you're
preparing to jump out of a *very* dangerous situation, *and your globe
gets hit again*?  More energy (possibly a great deal more, depending on
how many opponents you have to deal with) is channeled to your already
fully-charged jump drive capacitors.  Result?  Boom.

     What I was obviously insufficiently clear in saying was that it
was probably not a good idea to *plan* on using that particular method
of escape *unless* you have the added safety margin of a few extra
capacitors to deal with that pesky problem of last-microsecond hits to
the globe.  If jump capacitors were all I had, I would plan on using
different tactics (unless, of course I just happened to be in the
situation by chance--then I'd press the jump drive's "doit" button).

     I just like to have ample safety margins whenever possible--could
you tell?  ;-)


- - --
     Brent

INTERNET:  woodsb@gn.ecn.purdue.edu
USNAIL:  2818 S. Sunrise Dr.  /  New Palestine, IN  46163
PHONE:  +1 (317) 861-4844 (voice)


-------- TML Message #1793 --------

Archive-Message-Number: 1793
Date:     Fri, 16 Nov 90 8:58:42 EST
From: "Robert S. Dean" <rsdean@crdec8.apgea.army.mil>
Subject:  Maneuver Drive Rationalization

George William Herbert presented the salient pointsa of the discussion we have
been having correctly.  My own opinion on the matter, is, of course, to follow
m,y suggestion.  (-: (-:  However, a few extra points could be considered...
most heavily armored naval vessels can or do carry lightly armored auxiliaries,
which would still be larger than the typical players vessel, and could chase
them down as they tried to accelerate away at 2Gs.  Any retention of the volume
bases system needs a clear explanation of what happens in the close proximity
of a planetary surface when you attempt to use your maneuver drive (even if
that explanation is a clear statement that Nothing Awful Happens).  As it
stands now, there is a strange zone of incompatibilty when you cross the line
between "vehicles" and "spaceships" that would be retained.

By the way, does anyone out there besides Metlay go back as far as the first
edition of High Guard?  The one that clearly stated that you could use your
maneuver drive as a fusion gun in an emergency?  I, personally, would be in
favor of dropping this whole thrusters business and replacing them with
"reasonable" fusion rockets...something that the physics types cook up based
on "reasonable" fusion efficiencies, current engine weight categories, and
calculations starting with exhaust velocities of the resulting helium/hydrogen
stream.

Rob (its just my opinion) Dean

[I for one had a mint copy of Edition 1 High Gaurd in High School.  It
was so worn I had to glue in page hinges to keep the book from falling
apart.  I eventually gave it away when I got the second edition of High
Gaurd.  Just after I got the first edition, I did a "Trillion Credit
Squadron" sort of campaign with two of my players -- one designed a
dozen really big TL15 ships, and was so positive he was indestructible
he invited me (the ref) and the other player to do our worst.  With our
thrifty spending we built about 50 medium-sized TL13
battleships/carriers and a giant decoy ship.  They each carried about
500 100-ton modified scout vessels with 6G manuever drives and triple
beam turrets.  The Scout ships were surface-mounted on the
battleship/carriers.  When the battle began (instigated by the player
with hubris), the decoy lumbered out and immediately drew the proud
player's fire.  The scout ships launched, used their lasers as point
defense, and swarmed over to the attacking player's fleet.  The primary
damage inflicted was the point-blank fusion gun effect of the scout
manuever drives.  The battle ended predictably, with the
battleship/carrier player losing the giant decoy and only bring about
1/3 of his fleet into the combat -- the fusion drive scouts won the day.
Notably, I developed a statistical combat system for the scout ships -
since there were thousands of them flying around. -- James]

-------- TML Message #1794 --------

Archive-Message-Number: 1794
Date:     Fri, 16 Nov 90 9:16:12 EST
From: "Robert S. Dean" <rsdean@crdec8.apgea.army.mil>
Subject:  Black Globes, one more time

Someone mentioned synchronizing your weapons with the flickering of your
black globe generator.  Its a great idea...and it is also stated (although)
erhaps not explicitly) in the rules that that is what they do.  No need to
argue about it.

Rob


-------- TML Message #1795 --------

Archive-Message-Number: 1795
Date:     Fri, 16 Nov 90 13:27:08 EST
From: "Robert S. Dean" <rsdean@crdec8.apgea.army.mil>
Subject:  Re:  (1787) Bad News from the Physics Frontier!

Regarding your straightline vs. curve path for interplanetary travel: The
inefficiency factor is not worth considering as long as you actually have the
enrgy to do it...do you program an IBM compatible in machine language because
it gets you the extra performance?  No...because the performance that you get,
even wioth four layers of help programs and user interfaces that chew up a good 
deal of machine speed and memory is still greater than most people can keep up
with.  (e.g. your word processeor input buffer won't overflow no matter how fast
you can type).  Do you turn off your car's engine when going downhill?  No,
because gas is (still) cheap enough to ignore minor economies like that.

If you were going to go Earth to Jupiter (refueling pattern) at 1-G constant
boost, it would take how long (assume an average distance between the two).
Less than two weeks?  If the actual variation in path in less than 10% of the
total lenght, I'd say ignore it for game purposes...now if you have an old
TL8 asteroid miner with an ion drive, and an acceleration in the .001s of
Gs, this would be a different matter entirely.  I figured recently that Earth
to Mars at a constant accelration of .001G would take something like 289days,
which is a poor approximation, because I used the shortest straightline
difference between the two, and a course at this sort of acceleration would
be a much longer curve.  The Hohmann transfer time for mean separation of
the planets would be 360+ days (I forget the exact number).  Intuitively,
I should be able to trim SOMETHING off that by constant boost, however small.

Sorry about the typing today.  Much too tired.

Rob Dean


-------- TML Message #1796 --------

Archive-Message-Number: 1796
Date: Fri, 16 Nov 90 17:03:45 -0500 (EST)
From: William Dow Rieder <wr0k+@andrew.cmu.edu>
Subject: Revenge of the Manuver Drives

	Various people have been posting about manuver drives and how to make
them obey physics without changing the system too much.  I spent a fair
amount of time working on this last January, and posted some of the
results.  I'll summarize to conserve bandwidth.  My basic feeling is
that conservation of energy is worth fighting for, even if other physics
violations are used.
	It is IMPOSSIBLE to have a truly reactionless drive that does not
violate conservation of energy.  This follows from the principle of
relativity and the fact that reactionless drives by definition violate
conservation of momentum.  I can post a proof if there is sufficient
interest or disbelief.  It is possible to have a "pseudo-reactionless"
drive similar to grav thrusters.  The assumption needed is that the
vehicle with the drive is using it to push on the planet (or whatever)
just as if it had wheels and was in physical contact, conserving
momentum.  In order to conserve energy, however, the energy required to
accelerate at a fixed rate is going to rise steadily as the vehicles
velocity increases.
	Example:  A grav car massing 1000 kg that starts at rest accelerates at
1 meter/sec^2 for 10 seconds, giving a speed of 10 meters/second and a
kinetic energy of 50,000 kg m^2/s^2 = 50,000 joules.  This is the amount
of energy that must be provided to the drive assuming 100% efficiency. 
Now assume it accelerates for another 10 seconds at 1 m/s^2 (same
acceleration for same amount of time).  It is then is moving at 20 m/s
and has a kinetic energy of 200,000 joules for an increase of 150,000
joules, which must be provided to the drive.
	A plausible way for the drives to work is assume that they have a
maximum power, and the acceleration thus drops as the vehicle's speed
increases.  Also, some power input should be required to hover, even
though none is theoretically required, since the velocity is not
changing.  This "coupling energy" could rise as the vehicle gets farther
away from the planet, since the gravitational field is getting weaker.
The starship thruster plates could have a coupling energy that would not
depend on distance, as before.  Note also that braking would require NO
energy, and in fact you could get energy back (regenerative braking).
	One point that has been raised is the potential playability problem if
the formulas for acceleration are "too complicated".  Actually, they
will be much simpler than similar formulas for finding the acceleration
of an ordinary automobile (ever wonder why they give the acceleration as
0 to 60 in x seconds?), as well as being simpler than a rocket (mass
isn't changing).
	I am working on a set of rules for manuver and grav drives based on the
"pushing against a planet/star" idea and I'll post them soon.

	Sincerely,
			Guardian of Energy Conservation

					W. Dow Rieder

 	When the only tool you have is a hammer, all your problems
start to look like nails...

-------- TML Message #1797 --------

Archive-Message-Number: 1797
Subject: Re: Bad News from the Physics Frontier
Date: Sat, 17 Nov 90 13:00:03 +0000
From: Tim Day <tday@ps.ucl.ac.uk>

Orcinus orca <jokim@jarthur.claremont.edu> writes:
> 4 H  -  1 He  =  0.02916 grams/mole of matter converted to energy
> .....
> I think we have the reverse problem!  This process is too efficient!

It's still wrong anyway.  You can't fuse 4 H (=4 protons) into a He (=2 protons
+ 2 neutrons); you need two deuteriums (an isotope of hydrogen with a proton
and a neutron) or an ordinary hydrogen and a Tritium (=proton + 2 neutrons).
You could also have some exotic reactions with 3 atoms, or perhaps involving
lithium.

I always assumed Trav refining plants were heavy hydrogen isotope extractors,
although why having too much ordinary hydrogen in the fuel should cause
misjumps is a mystery.

Unfortunately I don't have a molar weight for deuterium handy.
+-----------------------------------------------------------------------------+
  Tim Day        tday@uk.ac.ucl.ps     | I honestly think you should sit down
  Department of Insanity and Surveying | calmly, take a stress pill and think
  UCL, Gower St., London  WC1E 6BT     | things over.               -HAL 9000
+-----------------------------------------------------------------------------+

-------- TML Message #1798 --------

Archive-Message-Number: 1798
Date: Sat, 17 Nov 90 08:51:03 PST
From: Vote For NoneOfTheAbove Write In Candidate 17-Nov-1990 1139 <baranski@meridn.enet.dec.COM>
Subject: Drive efficiency

In our drive discussions we've had statements from 'there's no way to do this
without violating energy conservation, there's just not that much energy in a
ton of hydrogen fusion' to 'the energy in a ton of hydrogen fusion is
infinitessimal to the amount needed, our drives must be horribly inefficient'.

My feeling is that over the changes in TL we should plan for a continum from
one extreme to the other in TDR, from where the drives are horribly
ineffiecent, to where you never fill your fuel tanks.  I think we should plan
rules to cover differing technologies of space drives.  It might be that you
have campaigns that use ion, fusion and fission rocket in the same game.

One other thought.  It might be that only a small part of the hydrogen used in
a spacecraft is fused.  It might be that the majority is used in the rocket as
reaction mass.  Possibly at some TL's it might be required for cooling
purposes.
On the other end of the spectrum, most people assume that the energy is from
the fusion of hydrogen to helium.  Has anyone considered fusion other elements,
or fusing multiple elements at high TL?

Jim Baranski
Norwich CT

-------- TML Message #1799 --------

Archive-Message-Number: 1799
From: "Mark F. Cook" <markc@hpcvss.cv.hp.COM>
Subject: DGP/TML Survey Deadlines
Date: Sat, 17 Nov 90 10:35:58 PST

This is just a quick note to remind everyone on TML that the deadlines for
return of the DGP and TML surveys are rapidly approaching.  The DGP surveys
will not be accepted after Tuesday, Nov. 20th, and the last day to submit
TML surveys Friday, Nov. 30th.

Our thanks to those of you who've already returned your surveys.  Everybody
else, remember, if you don't respond, you won't get a shot at the free
RPG give-away described in the survey header.  Also, for people who still
have not filled out their DGP surveys, remember that you can mail your
survey directly back to DGP if you don't want to submit it to us!

DGP will notify the winner of their give-away drawing directly.  We will
try to make an announcement to TML if the winner turns out to be someone
on the mailing list.

The drawing for the winner of the TML give-away will be made on Sunday,
Dec. 2nd.  The winner's name will be posted to the TML after we have
notified the winner directly and received a response back.  The TML
surveys will be processed and the results of the survey will be posted
to the TML some time in January.

Thanks again to all those who've helped us.

        Mark F. Cook

USMail: User Interface Technical Support
        Hewlett-Packard - Interface Technology Operation
        1000 NE Circle Blvd.  Corvallis, OR 97330

INTERNET: markc@hpcvss.cv.hp.com
          markc%hpcvss.cv.hp.com@relay.hp.com

-------- TML Message #1800 --------

Archive-Message-Number: 1800
Subject: FTL impossibilities, TDR stuff
Date: Sat, 17 Nov 90 16:55:13 EST
From: Robert P Poole <tarquin@athena.mit.edu>

Well, folks, I talked to a local Special Relativity guru.  Guess what?  All FTL
drive systems that rely on taking a ship out of our space-time and plopping it
temporarily in some "hyperspace" or "jump space" are going to violate
relativity.  (Specifically, you will invariably get reverse time travel.)
Here's why:

FTL, by definition, gets you from A to B faster than light can do it.  Once you
get to B, you can accelerate in normal space back to A until your velocity is
near c.  Start your FTL drive again, and you will arrive back at A in your new
reference frame, moving at just under c, some time before you left.  The only
way to solve this problem is to have ONE reference frame.  That is forbidden
under Special Relativity.

If you didn't follow that argument, here it is in a different form.  Say A is
the Earth, at noon.  Using your FTL, you jump to Alpha Centauri and arrive
there at 1 pm.  Accelerate in normal space toward Earth, get near c.  You are a
real stud and can take 40 G's of acceleration or whatever.  3 pm your time, 6
pm Earth time, but your reference frame still includes the Earth of two weeks
ago.  (Don't forget that information can't travel faster than light.)  Try
using your FTL again.  Whoops!  Back at Earth two weeks before you left.

What does this all mean?  Traveller doesn't work, nothing works, you are
doomed, SFRPG's will never be realistic.

Well, I think this underscores a more fundamental problem than all the physics
problems in Traveller.  Basically, folks, most of you have lost sight of the
fact that Traveller is a GAME.  In fact, it purports to be a ROLE PLAYING game.
If you're in it for space combat, tough shit.  There are many excellent space
combat systems available.  The point is to have fun.  Granted, some of the
inconsistencies grate on people's nerves, but when you get right down to it
there is nothing you can do without violating some laws of physics.

I'm not really flaming the efforts of people to make Traveller more bearable,
but what some of you are trying to do is model reality.  You can't do it.  I've
been watching all this talk about Black Globes and reactionless thrusters, and
I just have to laugh.  As long as you don't get a free ride (i.e., getting
something for nothing), what's the problem?  Who cares about the nitty gritty
details?  _I_ know the rules are "wrong," so do you.  {shrug}

Hopefully, the people who are going to spend all their time working on TDR will
realize that they are trying to fix the more broken aspects of Traveller
(trade, weapons, etc.) without losing sight of the fact that it is an RPG.
I applaud the effort.

As for ASCII, I can see how a lot of people would want to get straight ASCII
text and print it out.  I would recommend that the people doing this use Emacs
or else use a word processor that has an ASCII output option -- you're going to
want to use some kind of formatting for all those wonderful tables.

For those who want a nicer looking presentation -- something you can put in a
flex binder and show to people, or at least have readable -- I am willing to
put in my time and convert the final results into a machine-ready form so that
the docs can be typeset.  Then it is a matter of making the PostScript files
(or whatever) publically readable.  I would also be willing to make hard copies
and send them out via snail mail to whomever is interested in having nicely
typeset docs instead of unreadable dot matrix output.  (Just send me a check to
reimburse me for reproduction costs.)

And since no one on the TDR team is interested, I am willing to help coordinate
development of software for ship design, character generation, etc., assuming
that the TDR people are going to get all the algorithms to be self-consistent,
easy to understand, and amenable to computational algorithm.  Obviously, there
will be nothing to "jabber about and argue over until it dies of inertia" if
the TDR people do their jobs right.  IF.

I gotta see this.

Robert P. Poole                       tarquin@athena.mit.edu
46 Massachusetts Avenue               MIT Course VIII
311B Bexley Hall                      "We make Idols of our concepts, but
Cambridge, MA  02139                   wisdom is born of wonder."
                                         -- St. Gregory the Illuminator

-------- TML Message #1801 --------

Archive-Message-Number: 1801
Subject: System Generation stuff
Date: Sat, 17 Nov 90 11:07:05 PST
From: Richard Johnson <richard@agora.UUCP>

Jo - I missed your address.  *PLEASE* send me everything you've
got for sysgen.  I'd prefere the untested Sun version, but will
be quite content with the IBM version.  

Mark - I'm still waiting for those sector generators...

======
As you can see I've sort of decided to start archiving mapping
things.

Richard


-------- TML Message #1802 --------

Archive-Message-Number: 1802
Subject: Black Globes
Date: Sat, 17 Nov 90 11:09:37 PST
From: Richard Johnson <richard@agora.UUCP>

If *I* were inside a black globe, surrounded by lots of hostile
firepower, I'd charge the caps enough to jump, and then run
everything i had full tilt; maeuver drive, lasers, *anythng*
that would raise the background temperature of space inside the
bubble.  The more heat, the better.

Then whe I jumped out, it might fool someone for at least a few seconds.

:-)

Richard

-------- TML Message #1803 --------

Archive-Message-Number: 1803
Subject: Fusion
Date: Sun, 18 Nov 90 00:58:28 EST
From: Robert P Poole <tarquin@athena.mit.edu>

Tim Day wrote that 4 H -> He doesn't work, i.e., that you must have D or T in
the reaction.  Since when is it graven in stone that ordinary Hydrogen doesn't
work in fusion?  After all, our Sun does it that way (if you dare to disagree
with me on that point, I would be more than happy to discuss stellar physics
with you).  I see no problem with extrapolating a future technology which
allows fusion of ordinary hydrogen through some heretofore unknown exotic
process.

This means that Mr. Day's interpretation of fuel refining as extraction of
heavy isotopes from lighter ones (of hydrogen, that is) is WRONG.  As I
understand fuel refining, the difference between refined and unrefined fuels is
that unrefined fuels contain hydrogen in combination with other atoms (i.e.,
the fuel contains methane and water and other shit in addition to pure H).
This seems to be echoed by other physics-minded refs I've spoken to.  Military
craft are often fitted to use unrefined fuels, and presumably can refuel at a
gas giant or on a water world -- and this fits the general scheme of things.

Robert P. Poole                       tarquin@athena.mit.edu
46 Massachusetts Avenue               MIT Course VIII
311B Bexley Hall                      "We make Idols of our concepts, but
Cambridge, MA  02139                   wisdom is born of wonder."
                                         -- St. Gregory the Illuminator

-------- TML Message #1804 --------

Archive-Message-Number: 1804
Date:     Sun, 18 Nov 90 12:42:50 PST
From: Orcinus orca <jokim@jarthur.claremont.edu>
Subject:  Efficiency of Fusion

Tim Day writes:
> [can't fuse 4 Hydrogen to get one Helium]

That's what I thought, until I added the mass of 4 Hydrogen atoms
and found it to be greater than the mass of one Helium atom.  THinking
about it, a single hydrogen atom could be converted into a neutron
(neutron = proton + electron), so on paper, you could get a helium
atom from 4 hydrogen atoms.  I doubt it's so in real life.

There are a lot of other things involved (like neutrinos and such)
which I'm no guru on, so could some physics guru take over from here?
And I never expected my result to be the final word.  It was just a
ballpark estimate.

And as for "this thread is silly, Traveller is supposed to be fun":
There are some of us who think that trying to explain Traveller rules
in terms of real life lots of fun.  Oh yeah, if relativity is having
problems explaining jump drives, change relativity.  I'm sure Einstein
never intended relativity to account for *everything* in the universe.
- - --
John H. Kim
jokim@jarthur.claremont.edu
uunet!jarthur!jokim

-------- End of TML Messages --------

