Asteroid Size: Fixing Another Mistake in the Aerospace Engineers Handbook

Introduction

My attention was drawn yesterday (21st March 2023) to some more bizarre equations in the Aerospace Engineers Handbook. Not only were they wrong, but they were overly complex and not reduced to their simplest and most usable forms. This had the effect of bamboozling the reader.

I am fully aware some will be angry at me for pointing out yet another AEH error. Sadly, it's a very deep well to draw from.

The Weird Maths

Page 99 of the Aerospace Engineers Handbook has some calculations for asteroid size. The Math [sic, it's supposed to be written in British English] is given in this paragraph.

Firstly, let us note that the formula (1) for the volume of a sphere is incorrect. It reads as:

(1)

Which is obviously incorrect. The correct formula is:

(2)

This might be pedantic, but further examination gets interesting. In the rearrangement, tonnage (t) is used, and we'll assume t = V, and be charitable. I will also assume that R is supposed to be r; they're not the same. Remember, dividing by 4/3 is the same as multiplying by 3/4.

The attempted rearrangement (3) is:

(3)

The text then explicitly states this rearrangement, whilst forgetting the pi to yield another equation (4):

(4)

This is all patently nonsense. (3) is not the rearrangement of (1) or (2), and it is written in a bizarre way in its' original form. Ultimately, when you write it as (3) and compare to (6) below, it's clear that pi is the problem, and the final answer will be wrong by pi^(2/3). For a 1,000,000 dTon asteroid, the true value of r is just under 150 m, whereas (3) would give a value just over 320 m.

 

Fixing and Simplifying The Maths

So, what should the correct formula be, and how far can we simplify it? For maths to be used in a game, we want the equations to be as simple as possible, but correct.

Taking the correct equation (2), and rearranging for r yields (5-8):

(5-8)

Where (8) is rounded and is ca. 0.3% off the real value.

Rearranging to get volume (in dTons) from the radius:

 (9)
 

With the constant less than 0.3% from the true value by rounding. I think everyone can agree that (8) and (9) are elegant and usable. If I want the dtonnage of an asteroid, I cube the radius and multiply by 0.3. No messing about. The 1,000,000 dTon asteroid is just under 150 m in radius by (8).

I thus commend the corrected equations (8) and (9) to the Mong2k3 community.

Making DNAM's in Mongoose 2300AD follow Mongoose Traveller Rules

Introduction

Mongoose 2300AD (the 2012 version at least) is simply a reskin of QLI's 2320AD. I noticed when looking at the DNAM (DNA Modification) rules, trying to calculate the chance of dying if infected with the DNAM virus (about 1 in 6 in the original GDW rules) that very little had changed from 2320AD. Indeed, for the most part only the only change was from D20 difficulty class to a Traveller difficulty class. However, Mongoose Traveller rules are more subtle than D20, and the effects are graduated.

A search through the rules has shown only one task properly formatted for Mongoose Traveller; exceeding the 7.7 ly limit. This was an addition, which was not present in the 2320AD text. This is general - tasks that were present in 2320AD were not properly reformatted to the Mongoose Traveller rules, with only the DC changed, and the graduated success system ignored.

There was one other change, which was a clarification of the 2320AD rule, which was ambiguous. However, the Mongoose Traveller resolution goes in the wrong direction from a scientific standpoint. I'll address that at the end.

This will properly adapt the DNAM rules in 1st edition Mongoose 2300AD to Mongoose Traveller rules. If the 2nd edition fixed this, I'd love to know. I own every product from the 1st Mongoose edition that got a physical release, but only the AEH from 2nd edition. The AEH was so poorly done that it put me off buying anything else at those prices. 

 

The Task Systems

We have three task systems in play; (GDW) 2300AD, T20 and 1st ed. Mongoose Traveller. 2300AD and Mongoose are both derived from the Megatraveller task system with refinements and modifications.

2300AD (2nd GDW ed.) used a d10, with a base target number of 6+ for routine tasks, and difficulty levels moving in bands of 4 (10+ for difficult, 2+ for simple etc.). Several different bonuses could be used. The time taken was 3d6* the listed time. Failure meant rolling on a failure table that could allow a go-around, prevent another attempt, or do serious damage for a fumble, upto straight death in the case of the DNAM transformation. The bonuses were characteristics (0 to 5, with the norm being 2 or 3) and skills. Traveller:2300 had a general target number of 7+ for routine, but rolled effectively on a d10-1 (i,e. 0 was read as 0, not 10), for a lower chance of success, but with the same consequences.

Mongoose uses an elegant modification of Megatraveller, wherein the roll is 2d6 and the base target 8+. Modifiers are applied to the roll, including difficulty in steps of 2 (-2 for difficult, which equates to a 10+ target etc.) and bonuses on the same scale as 2300AD. The interesting wrinkle is that the degree of success of failure is determined simultaneously by how well you beat (or failed) the dice roll, thus:

• Beat the target by 6 or more = exceptional success. It worked brilliantly, having better than expected effects.
  
• Beat the target by 1-5 = success. It worked.
  
• Beat it by 0 (i.e. rolled the target) = marginal success. It sort of worked, but with caveats.
• Failed the target by 1 = marginal failure. Almost succeeded.
• Failed the target by 2-5 = failure. It didn't work.
• Failed the target by 6+ = exceptional failure. You make things much worse.

Bonuses are characteristics (-2 to +2, with -3 and +3 being just possible but vanishingly rare and 0 being the norm) and skills.

The D20 (i.e. 3rd edition of Dungeons and Dragons) system used by T20/2320AD rolled a d20 against a difficulty (10 for average tasks, 15 for tough tasks etc.). Success/failure is digital, with no gradations and no possibility of a fumble. Characteristic modifiers go from -4 to +4, with 0 being the norm (a characteristic of 10-11 is a zero, 12-13 is +1, 14-15 +2 etc. in both directions).

What Is a DNAM?

As described in the GDW core canon, the virus is a "controlled cancer." It mutates cells and has them proliferate rapidly. The new tissue displaces the old tissue. It changed between editions. In the 1st GDW edition it was described as an emerging experimental procedure, but the author of the King section of the Colonial Atlas relocated the first use back to 2192, and so the experimental line was deleted in the 2nd edition in a retcon. As described in the CA:

At first, the extreme gravity of the planet made any form of extensive colonization unthinkable. Despite these problems, the lure of King's natural resources demanded that the scientific community find some way to overcome this problem. After numerous attempts
at mechanical compensation had proven impractical, a team of researchers working in conjunction with the Canadian government found a solution. In 2192, they created a new form of life, known as DNA Modifiers (or DNAMs), that was to open King up to
colonization.

Similar in structure to Terran viruses, DNAMs enter the cells of the host's body and make changes in the structure of their DNA. When the altered cells reproduce, the offspring are unlike their parents in some way. One of the changes induced by all forms of DNAM is the rate of reproduction. The modified cells multiply much faster than their normal counterparts in a manner that has been likened to a controlled cancer. Once all of the cells are changed, the rapid growth slows to normal, and the intruding microbes die off. In most cases, it takes just over a month for the DNAMs to do their work in a human body. During this time, the host is normally kept sedated in a medical facility.

The task profile to undergo DNAM transformation is as follows: To undergo DNAM transform: Simple. - Physical Endurance. 3 days.

DNAM transformation is a hazardous task. If the task results in failure, a roll of "retry" means the DNAM was rejected by the body and "check determination" indicates the DNAM was rejected with unpleasant side effects. If a mishap is incurred, "superficial
damage" results in serious, permanent medical complications as a side effect of the DNAM rejection. Any result more serious than this level indicates death. It should be noted that Physical Endurance acts as a negative modifier since a stronger immune system will act to resist and complicate the transformation process.

If the task is successful, the character's body type is converted to "mesomorph" (this change is in game terms and not so much in appearance). To reflect this, the original physical attribute modifiers should be neutralized and the mesomorph modifiers applied. Beyond that, DNAM modified characters receive +(1D6-3) to Strength and Physical Endurance and -(1D6-4) to Dexterity. In each case, the minimum modifier result is 1. This task process should be performed during character generation (at the end of step three in the character generation checklist) if a player wishes to run a King colonist as a PC.

As a task, it is roll 3+ on a d10 to succeed, but with the endurance characteristic (on average 2.5) as a penalty, leading to a 45% chance of success on average. It takes, on average, about 30 days (3d6*3 days). As a hazardous task, the effects of failure can be extreme, and there is a 50% chance of a mishap or serious mishap. If you get a mishap, you have a 50% chance of dying, and a serious mishap is 91% dead. This averages as a 60% chance of death if you have a (serious) mishap. The chances of dying outright are thus 55% * 50% * 60% = 16.5% or 1 in 6. (See here)

If played with 1st edition Traveller:2300, reformatted to a normal d10 the target number would be 5+, and so success would occur 25% of the time, and death would be proportionally more common.

I would argue from the biological standpoint that if you fail the roll, you have antibodies against the DNAM and can never attempt it again, but that's not stated. If you allowed the players to keep going round it would ultimately resolve as 73% transformed, 27% dead.

Mongoose Task: Being Transformed by the DNAM Virus

The 2320/Mongoose rules define major or minor DNAM's, with the difference being a major DNAM is no longer Human, and cannot breed outside of their race. Minor modifications are done on an outpatient basis, and take a month to complete, whilst major modifications require three months as an inpatient, generally sedated.

For Mongoose, the Fortitude check was simply changed to an endurance check. However, the degrees of success/failure were not changed. The digital D20 system was kept in place. Adding the degrees of success/failure to the task would be:

• Exceptional success: basically impossible, but perhaps remove (some of) the negative effects of the DNAM from the character.
• Success: the character is transformed with no long-term effects.
  
• Marginal success: the character is transformed, and must save against long-term permanent medical complications with a +2 bonus.
  
• Marginal failure: the character is transformed, and must save against long-term permanent medical complications.
  
• Failure: the character is not transformed, and must save against long-term permanent medical complications.
• Exceptional failure: character is dead (or reduce endurance by 2d6+1 and make them crippled).
  

For the save vs permanent damage, make a routine (8+) endurance check for a minor DNAM or difficult (10+) for a major DNAM. On a exceptional success there is no damage. On a success the character permanently loses 1 endurance, or 1 plus special effects on a marginal success. On a marginal failure the character loses 1d6 endurance without additional effects, and 1d6 with additional effects on a failure. On an exceptional failure the character loses 2d6+1 endurance and crippled/ killed.

In the event of permanent medical complications, in addition to reduced endurance, other effects related to the specific tissues the DNAM virus targeted will occur. With a thinair modification, the lungs are seriously damaged, causing the requirement to use a respirator for example. With a King DNAM they get brittle bones and damaged heart tissue etc.

Whether repeating the DNAM treatment on a failure is possible is an interesting issue. In 2320AD the rules was that a second treatment made the character extremely ill if success, and was often lethal if failed (on the second try). A third try was impossible. In Mongoose, this was changed, I think by a simple misreading, and you had two tries with a third being impossible, but also rules for damage if the third try failed. There was also penalties for having multiple DNAMs (-2 on the rejection save per minor and -4 per major).

Given the ambiguity in the status of the third attempt, the best solution is to have cumulative penalties per DNAM attempt, whether successful or not.

Thus, for multiple attempts, each attempt at a major modification, successful or not, inflicted a -4 penalty on all future DNAM attempts, whether the same virus or a different one (since the carriers will be similar). For each minor attempt, a -2 penalty is accumulated.

Probabilities

Assuming a difficult DNAM (i.e. King) as the norm, probabilities are:

For a normal colonist taking the King DNAM, they have a 1 in 6 chance of dying in the attempt, and a 28% of being transformed (with or without complications). This is the same chance of death as the GDW King DNAM, but a slightly lower chance of success using 2nd edition, or a higher one than 1st edition. All in all, the numbers are roughly consistent with the GDW canonical numbers.

 

A normal colonist taking a simple DNAM (8+) is the same as on the +2 column, and is transformed nearly 60% of the time, and the death rate is around 3%.

 

Balance

These rules utilise the improvements in the task system of Mongoose Traveller over D20 2320AD. They give a graduated range of possibilities, and have a strong possibility of dying or doing serious damage to a character. They preserve the danger of DNAM in GDW 2300AD, which was largely done away with in 2320AD, and hence give a result closer to the prime canon.

Further, the strong possibility of a serious mishap acts to balance the DNAM and explain the low rate of DNAMing. Most people simply wouldn't deliberately give themselves a form of (hopefully controlled) cancer in order to get a stat bonus.

Ta-180m: How much in a stutterwarp drive?

Introduction

Tantalum is the "magic ingredient" in stutterwarp drives. It's availability and politics fundamentally shaped the (GDW) 2300AD universe.

The idea that the stutterwarp used the Ta-180m isotope was mine, not GDW's. GDW simply picked a rare element whose distribution of known mineral reserves looked like it would give a good universe. I noticed that Ta-180m's transition to Ta-180 would fit the effect of a drive breach exactly. Thus I proposed that the stutterwarp used Ta-180m. This proposal predated Colin Dunn getting the 2320AD gig, and hence joining the 2300 communities. It was incorporated in Mongoose 2k3 without attribution to the original source (me). As the "original inventor," I believe I can comment on it. Colin has even noted (in 2010) that it was fanon (i.e. mine).

The question is, how much Ta-180m would a drive need? It must fit both the observed effects of a drive breach, and the production of starships.

Tantalum-180m Quantities

Ta-180m is spin trapped. The nucleus is spinning on its axis fast enough that the nucleus is not spherical, but prolate (i.e. rugby ball shaped). The nucleus can flip between prolate and oblate (i.e. the axis of rotation), but it is not both simultaneously, unless excited into a very high energy state where it flips so fast between the two states that it has some existence as the intermediate sphere (K mixing). This sphere can (and does) decay into the ground state, releasing the energy (and spin) as a burst of X and gamma rays. The m spin state is 74 to 77 keV above ground, and K mixing occurs 2.74 MeV above the m state. These equate to ca. 10 times its mass in TNT (9.65) and ca. 350 times its mass in energy terms.

The gravimetric charge is probably stored in the Ta-180m by increasing the energy of the nucleus. As they get charged, they flip more and more frequently. The actual quantum states will obey a Boltzmann distribution, and so the possibility of some of the Ta-180m reaching 2.74 MeV occurs well below all of the Ta-180m being charged (see appendix).

The effect of an uncharged or charged drive breaching is described in a task in the GDW boxed set:

A total failure, i.e. the destruction of the drive, results in an EP = 5 explosion. This would be the result of the Ta-180m relaxing, and it would take ca. 50 grams of Ta-180m to release that energy, assuming 100% efficiency and that all the tantalum went up. In reality, without a charge, no chain reaction would occur, and this is just a small fraction of the tantalum going up. No chain reaction would occur as no high energy gamma is released to pump surrounding atoms. Thus the 50 g is a floor. It would have taken isotopic separation of ca. 500 kg of tantalum to produce 50 g of the star drive grade.

From the other side, there were a few hundred thousand tons of tantalum on Earth. 300,000 tons would give ca. 36 tons of stardrive Ta-180m. The number of stutterwarps built in Human history upto 2300AD is maybe 10,000 (3,300 starships in 2300AD, plus missiles, losses etc.) Much of this tantalum came from offworld, probably a majority of it. If, say 84% of the tantalum came from offworld, then an average drive has ca. 50 kg of Ta-180m in it. Call this the ceiling.

In all likelihood, a typical drive might contain, say, 0.1% of the drive mass as Ta-180m. This would be an intermediate value that would fit the amounts available to give the canonical numbers of ships. A Kennedy class light cruiser would have 85 kg of Ta-180m, which needed ca. 700 tons of tantalum isotopically separated to supply it. Known reserves on Earth would be enough for ca. 400 Kennedys without missiles, although each load of missiles would consume ca. 1,200 tons of tantalum.*

Currently, without using it for stardrives, tantalum metal is $250/kg. 700 tons would be 175 million dollars (i.e. MLv21.9 using GDW livres**), and represent much of the Earth's annual production. Notably, this is less than the cost of the stutterwarp drive.

Core Breach Effects

What about the breach of a charged drive. The energy of saturated Ta-180m is ca. 350 times it's mass in TNT (1.46 MJ of gamma per g Ta-180m). It's likely that it is impossible to reach 100% charge, as the amount of charge will be in a distribution. The description of shutting down a drive says that the charge concentrates on the still active parts of a drive, and when a part saturates it breaches.

We should note that the description has implications for space combat. If a ship has a charged drive, and battle damage causes it to be offlined, then the drive will breach, with all that implies.

Using Grays (Gy) as our radiation measure, 1 Gy = 1 joule of absorbed radiation per kg body-mass. The LD50 (the dose at which 50% of people will die of acute radiation poisoning) is 3 Gy, or 210 j of gamma for a 70 kg person. Humans absorb about 50% of the applied gamma, and was 420 j of gamma applied would be LD50. If there is no shielding etc. when a human would be exposed to this from 1 g of saturated Ta-180m 20-30 m from the reactor.

100 Gy, which would kill in minutes, equates to about 14,000 j applied (i.e. more energy than a .50 cal bullet). For 1 g of saturated Ta-180m, this is ca. 1% of the theoretical emitted energy. You'd need to be 2-3 m from the drive to receive that from 1 g of Ta-180m, assuming no shielding. This would likely place you inside the drive.

With the frequencies involved, about 3 mm of lead attenuates 50% of the gamma, or 1 cm of steel. Assuming a casing of 2 cm of steel or so, only 25% of the gamma would escape the drive.

The drive is not likely to be fully saturated. In fact, it is likely to be only around 1-10% of saturated.

If we set the "instant kill" radius at 20-30 m (100x), shielding at 25%, and the amount of Ta-180m crossing the activation energy at 1%, the total Ta-180m in the drive is now 40 kg. Ergo, with these simple assumptions, I am in the same range as above.

Depleted Tantalum

After isotopic separation the depleted Ta-181 is chemically still tantalum, and is an extremely useful and expensive metal used in capacitors etc. Indeed, I can remember someone (Ben Levy, I believe) pointing out that this might create a glut of Ta-181, or "depleted tantalum." It could well be that depleted tantalum jewelry becomes a thing for example. The unscrupulous might try and pass off depleted tantalum as genuine etc. There's a game hook for you.

Mongoose 2300AD and Tantalum

As I have noted previously, Colin, the Mongoose 2k3 author, has tried to remove the tantalum limits of 2300AD. The tantalum issue is one of the core conceits of 2300AD. By removing it, the universe doesn't make sense, but it allows the Libertines to exist (see here for similar on the Mongoose forum in 2013). I understand his reasoning, but it is flawed.

In the 1st Mong edition, Colin got the element wrong, and stated it was Ta-180 (1st Mong 2k3, pgs 3 and 265, itself a word for word reprint of 2320AD pg 309). This has a half-life of 8 hours. The incorporation of Ta-180m proper occurs after a 2014 facebook thread in which I corrected the matter. However, he took his queues from me and wrote in the 1st edition (pg. 265):

Tantalum is a very rare element and the isotope Ta-180 even more so. The Ta-180 isotope is the only one that can be used in a stardrive. It has only a limited availability and although the quantities used in the construction of a stardrive are relatively small, it is still a managed resource. This limited availability ensures that only a limited number of ships can be built per year. A tantalum-180 find of any size is enough to make its discoverers very wealthy.

However, in the few years afterwards he switched to a far more neoliberal economic model. In fact one far more libertarian than the most extreme Chicago school economists. There is a lot of this as the Mong 2k3 run continues, it lurches far to the economic right.

In the 2nd edition (AEH, pg 3), Colin states:

The limiting factor in the construction of new vessels is the rarity of an isotope of tantalum. This isotope, Ta-180m, is one of the rarest in the universe. Fortunately, a starship drive only requires a few grams.

This is demonstrably incorrect. It exists only to try and remove the tantalum limits. Whilst he is free to change how he plays his game (which, of course, alters the Mongoose universe), he can't change the prime canon.

Also, a few grams would not be dangerous if it breached. Thus this interpretation fails both the criteria it needs to fulfill.

Conclusions

Within the core universe, tantalum limits starship production. Following various factors, the amount of highly enriched Ta-180m in a stutterwarp is about 1/1,000th of the mass of the drive. This allows for an approximately correct number of starships, and for the effect of a drive breach to scale correctly.

The alternative idea, that there are grams instead of kg of Ta-180m, doesn't address either the starship numbers, or the effects of a drive breach.

Notes

 * This is completely in keeping with canon. See the 2nd edition Director's Guide, pg 78.

** Note: GDW and 2320AD (and derivatives) livres are not the same. The value of a GDW Livre is 3 US dollars ca. 1986. The 2320/Mongoose livre is pegged to the Traveller Imperial Credit at 1:1, and hence is the value of one ca. 1977 USD. The conversion is 1 GDW livre = 5 2320/Mongoose livres. For converting modern USD to GDW livres, divide by 8.

Appendix: The Boltzmann Distribution

Boltzmann distributions look something like this:

As the general energy goes up, the distribution shifts right. At a certain point, a small portion of the distribution is beyond the activation energy for a reaction. This chart is actually gas particle velocity at increasing temperatures reskinned, but the underlying concept is the same. It does mean that only a tiny fraction of the distribution reacts.

Power in Mongoose Traveller/ Traveller:2300

The Problem

In Mongoose Traveller 2nd edition, rather than real measures of energy, an abstract system of power points (or just "power") is used. There is speculation that each unit is many MW. However, from the general size of reactors, by comparing them to real reactors we can tell this isn't true. In the Aerospace Engineers Handbook, Colin went with the round 0.1 MW per power. This is far too high still.

(Note: none of this applies to 1st edition Mong 2k3 as far as I can tell, the original system I wrote was a straight conversion, and system used in 2320/1st Mong was at least inspired by it.) 

GDW nuclear reactors are the right size. They fit with modern reactors, and there isn't much improvement that can be made. Ergo to get 1 MW, you need 4.8 dTons of fission reactor. Assuming the real reactors map to advanced fission reactors in the AEH, 4.8 dTons is 38.4 power, and so 1 power resolves as 1/38.4th of a MW, or 25 kW to a reasonable rounding.

Reactor sizes are allowed to be much smaller in the AEH, with fission being allowed to be 20 dTons and fusion 60 dTons. This is apparently simply because the minimum power was kept constant, and hence everything moves around it.

In mathematical terms, the conversion of MW to power resolves into two simple arithmetical equations, one of which can be substituted into the other to give the correct result.

In short:

1 power = 25 kW

40 power = 1 MW

This is a general result for the whole of the Mongoose Traveller line.

 

An Aside: A GDW Mistake

GDW made a mistake in the density of H2/O2 fuel. To get a density of 0.6, 1 molar equivalent of hydrogen is reacting with 1 molar equivalent of oxygen. This is stoichiometrically incorrect, and 2 equivalents of H2 are needed per mole of O2, giving a density of 0.43. GDW engines run very oxygen rich. This is the opposite of the real world, where an excess of H2 is used (33% excess) to assure the use of all the liquid O2 (the heavier component).

Hydrogen produces 120 MJ/kg of usable energy when burned. We ignore the O2, as long is it sufficient to burn the fuel. Converted into Mongoose Traveller, 1 dTon of H2/O2 contains 205.9 kg of H2 assuming exact 2:1 stoichiometry (i.e. all the H2 is burnt with no leftover O2). The energy content of 1 dTon of fuel is thus 24,706 MJ or 6.863 MWh. 

I should also note that GDW got the efficiencies of fuel cells and MHD turbines correct in the boxed set, but reversed in Star Cruiser, and corrected this in errata. An MHD needed 75 metric tons of H2/O2 for 1 MW-week by the rules, but most were made with the 100 ton superceded rule.

Using the real world moderate excess of hydrogen (which gives 4.5 kps exhausts), I can keep the volume of H2/O2 the same at 165 m3/MW-week, but the mass is reduced to 60 tons from 75 or 100. This gives a moderate boost to conventionally powered ships. An Aconit now has 840 metric tons of fuel instead of 1,400/1,050 tons and is warp 1.67 fully fueled.

The Aerospace Engineers Handbook

The stutterwarp equation is broken in several ways, meaning it doesn't produce similar results to the original. This creates a problem wherein designers using it have to make a conscious effort not to break the game.

There were so many problems with the stutterwarp, that this one is broken out to a separate post. To fix the problem, multiply all power requirements of all systems in the AEH by 4, to reflect the "true" value of a power.

This also fixes the MHD turbine issue, wherein the turbines were several hundred percent efficient. In fact, this simple rescale fixes prettymuch everything:

1. Nuclear and fusion plants scale as per reality
2. MHD Turbines and Fuel Cells now have ca. 60% rather than > 200% efficiency
3. Solar panels have realistic efficiencies of ca. 37-50% rather than 180-270% as in the AEH

On the solar panel point, the intensity of sunlight in Earth orbit is 1.36 kW/m2. So 272 kW falls on a standard solar panel. For 4 power (100 kW in the revised scale), a basic solar panel is 37% efficient, which just under the theoretical efficiency we're striving for (good panels are ca. 15-20% efficient now).

Here I should note that neither Mong 1st edition 2300AD, nor the AEH mention that sunlight intensity depends on the distance to the star. Solar light intensity falls off in proportion to the square of the distance from the star. The standard solar array produces 4 power at 1 AU from Sol, but at 5.2 AU (Jupiter orbit) it would produce 4/(5.2^2) = 0.15 power and roughly 7 standard arrays (1,400 m2) are needed for 1 power (whatever the scaling). To provide meaningful power in the outer systems, solar arrays measured in 10's of square km are needed.

Conclusions

The problems of > 100% efficiency etc. can all be fixed by scaling 1 power at 25 kW. At this scale everything that I've inspected basically is realistic.

 

2300AD Changes (3a): Stutterwarp Part 1

Introduction

Stutterwarp is the one declared physics violation in the 2300AD universe that is a feature, rather than a bug. During the 3 editions under Colin, stutterwarp has changed somewhat.

In 2320AD, we were forbidden from making any changes to canon, and so stutterwarp was discovered on schedule, and worked the same way. In the 1st Mongoose edition, things moved well away from the established canon. In the 2nd Mongoose edition, some disastrous visits from the "good idea fairy," that creature who whispers in all 2LT's ears to the chagrin of their Pl Sgt, have left stutterwarp itself broken, and the history in a bit of a shambles.

I don't have the 2nd edition core set (ask me when the PDF is 25 euros or less), so don't know what changes Colin made there, but I can see from comments on the Mongoose boards there are some random changes. I do have the Aerospace Engineers Guide, and will comment on stutterwarp in that.

As a note, I will only give references once, when they are introduced, and not again if they are used multiple times.

A Short Note

In the process, I dumped 2320AD and 1st edition Mong 2k3 into MS Word and hit compare. Mong 2k3 (1st ed) absolutely is just an edited version of 2320AD. This of course shows in things like the colony table showing everyone on Hochbaden being dead - an event that occurred in 2301. Errors like the French military junta continuing until 2299 are present in both, with identical text. (2320AD, pg 53 and Mong 2300AD 1st ed, pg 20) In fact, the Junta fell in 2293, Ruffin was elected President in 2294, re-elected in 2298 and crowned Emperor in the same year. (2300AD Adventurer's Guide, pg 66)

 

PART 1: CHANGES IN GAME HISTORY RELATED TO STUTTERWARP

The Discovery of Stutterwarp

In prime GDW canon, the theoretical basis of the stutterwarp was an experiment carried out at CERN in French Switzerland in 2086 (2300AD Adventurer's Guide, pgs 64-5), and the first actual drive built by a consortium of French, British and German (not Bavarian, "German") scientists there in 2136. The flash-to-bang for the discovery of the Jerome effect to actually having a working drive was 50 years. This was installed on an unmanned probe and launched at Alpha Centauri that year. (Nyotekundu SB, pg 4). Notably, it arrived in 2137, so it must have been late in the year. (Colonial Atlas pgs 4-5) There is some indication that stutterwarp drives were slow, as the first manned ship (by the ESA) arrived insystem in 2139.

The ESA lacked tantalum. The British brokered Azanian entry into ESA in exchange for tantalum, and in 2139, the same year the manned survey ship went to Tirane, ESAS Pathfinder surveyed the nearer systems of the French Arm. At the time, the stutterwarp didn't have a 7.7 ly range. The unmanned probe to Alpha Centauri had to carry multiple drives, dump them as they filled and power up a new one. ESAS Pathfinder was also in this era, and would have burned through 12 drives in it's run.

The Colonial Atlas says an Argentine probe followed in 2138, with Japanese and American ones soonafter. However, America's first stutterwarp effort was joint with Australia, and was an unmanned probe Connestoga to Barnard's Star in 2155, followed by the first American-Australian starship (Crux Australis) being the (assumidly) first ship to go to Barnard's Star in 2157. (Earth/Cybertech SB, pg 40) America didn't return to manned orbital spaceflight until 2151, and probably built their first national starship (Hermes) in the 2160's or so. (Colonial Atlas pg 85) Generally, the writer of the Tirane article kept confusing America, Australia and Argentina, and this is probably an example of it.

The improvements that led to a "modern" stutterwarp with 7.7 ly range etc. were published in 2147, and from then on the need for multiple drive vessels etc. was obviated. (Challenge Magazine, Issue 28, pgs 41-42)

Here I should note that in Challenge 30 (pg 38) gives different dates; 2080 for Jerome's experiment, and 2126 for the first ESA starship (Prometheus). It also gives different politics. Challenge articles aren't canon, and these statements are overwritten by the Nyotekundu Sourcebook. This was retconned in 2300AD 2nd edition (Adventurer's Guide, pg 22) with Jerome performing an initial experiment in Grenoble, and then the CERN experiments of 2086 giving the basis of stutterwarp. The first probe is launched in 2136.

Thus we have our basic timeline for the stutterwarp:

• 2080 = Jerome jumps a single hydrogen atom in the Grenoble accelerator
  
• 2086 = Work at CERN in French Switzerland gives the theoretical basis of stutterwarp
  
• 2136 = actual drive, first probe (probably named Prometheus)
  
• 2139 = actual starships flying, Tirane survey
  
• 2147 = improvements leading to the 7.7 ly range.

2320AD's history section is essentially a copy-paste job from GDW, and whilst it has both 2080 (pg 307) and 2086 (pgs 8 and 209) for the discovery of the Jerome effect, it tracks prime canon with a 2136 first starship, 2163 AC War etc. It adds that second generation stutterwarps became available ca. 2167, which I assumed was OM/NC tech. However, in later work he defines this as the pre-modern (< 7.7 ly range etc.) drive.

Mongoose 1st edition rewrites the dates thus:

• 2080 - Jerome performs his experiment (pg 263) 
• 2088 - Melbourne Accords first signed (pg 23)
  
• 2103 - Jerome dies (pg 263)
  
• 2112 - Zombie Jerome performs his experiment, again (pg 6)
• 2119 - Melbourne Accords first signed, again (pg 6)
  
• 2136 - first unmanned stutterwarp probe (pg 263)
  
• 2144 - first starship (with a 7.7 ly range?) (pg 263)
• 2146 - first starship, again (pg 6)
• 2149-54: Alpha Centauri War, ending with ESA signing the Melbourne Accords (pg 7)
• 2183: ESA signs the Melbourne Accords, ending the Alpha Centauri War, again (pg 6)
  

Mongoose 2nd edition, as initially published, had 2105 for Jerome's experiment and 2132 for the first starship, but with the precursor unmanned probes being launched in 2136 still. The AEG says that generation I drives were more susceptible to an "inversion" (i.e. were shorter ranged), and warp efficiencies should be divided by 10 (AEG, pg 118). It moves the adoption of generation II drives (i.e. "normal" drives) to 2190 (AEG, pg 108). This alone should probably push back settlement of Tirane into the 2190's, and we should have a roughly 30 year frameshift. Including the insystem parts, a warp 1 vessel takes 8.9 days to go from Earth to Tirane (Tirane is officially 1.41 AU from the FTL shelf). A generation I vessel is thus on the 3 months each way time scale. This means conventional power is impossible to utilise (unless six months fuel is carried), and all vessels need nuclear reactors. A vessel could not make many trips per year, and the colony ships to Neubayern or Queen Alice's Star would take years for a round trip. This should reduce the population of those worlds be a factor of ca. 4.

 

Early Starships and the Melbourne Accords

The Melbourne Accords accords were signed in 2099 in prime-canon (AG, pg 64), but in 2320AD were signed in 2099 (pg 7, a copy-and-paste from prime canon), or 2088 (pg 58) or in the 2160's (pg 73). 1st edition Mongoose is a copy-paste effort from 2320AD but some of the dates are edited. 2088 is repeated (pg 23), as is the end of the Alpha Centauri War (pg 33, but see in a couple of sentences). However, the dates are edited in the history text to change 2099 to 2119. (pg 6) The date of ESA signature, which ended the Alpha Centauri War, is given as 2183 instead of 2163.

Yes, Mongoose 2k3 moves the Alpha Centauri War by 20 years. This should frame shift the whole of Human settlement by 20 years. Except, it hasn't. The ESA colonies on Tirane were still settled in 2167 - all of them. Even the colonies which were settled later are still listed as being settled in 2167. Why is Argentina fighting to be allowed to place a colony on Tirane in 2183 when they already did so in 2167?

As a further note, OQC was absolute in core 2300AD. No ship had ever successfully run the blockade. Mong 2k3 proclaims L-4 is outside the jurisdiction of OQC, which is probably is. (pg 31) However, this completely misses the point - when entering OQC's jurisdiction (i.e. heading to Earth) at that point it is either searched, or destroyed. It makes the bold claim that lighting up a nuclear thermal rocket in Earth orbit won't be seen.

 

Jumpers and Exploration

In 2nd edition Mong 2k3 there is a new visit from the good idea fairy in the form of "jumpers." If they were in 1st edition, it wasn't in the rules book. These jumpers were separatists or cultists who left Earth for the stars 2130-2170. One should note that in 2130, in all versions, the stutterwarp drive hasn't been invented yet. In the Mongoose continuity, when the last jumpers leave, ESA perhaps hasn't even sent their first colony ships to Tirane, triggering the Alpha Centauri War (which appears to have happened in 2182 rather than than 2162 in that continuity).

The idea that religious whackjobs are building or buying starships before the great powers and heading off into the big black stretches incredulousness. That they got as far as Paulo, Doris (which Colin renamed Kanata for no good reason) and Avalon > 100 years before the professional explorers stretches it further. Doris is 81.69 real light years, and with the insystem journey components the ship would need at least 3 years to reach it. All of the crossings except one are > 3.85 ly (the early drive limit in prime canon which is alluded to in Mongoose).

Then there is the question of how they navigated?

When entering an unexplored system, the first question is where can I discharge? Some explorers can get around this by jettisoning the charged drive if necessary, because they can carry a spare. Without knowing this, you are looking for a body to discharge at, whilst the drive is charged. Now, the techniques used for exoplanet hunting generally don't work. We can only see a fraction of planets, and no increases in resolution etc. will compensate for there literally being no signal. Thus, when an explorer enters a system, they are reliant on their own sensors, or those of probes, to find a reasonable body to discharge the drive at.

Without belabouring the point, there has to be some limiting factor to explain why Man's forward exploration moved forward at about one star system per decade. The counterpoint is, of course, the Bayern module, but that can be explained away perhaps by advances in technology in the 150-odd years since the Jumper times.

Why is The History so Inconsistent?

2300AD/2320AD under Colin Dunn has made major revisions in the history etc., but they are inconsistent. Colin started by just doing a copy-paste text dump of the original GDW history sections etc. in 2320AD, and hence these are consistent. However, when he wrote about the history outside of the copy-paste, significant errors crept in.

In Mong 2k3 1st edition, he made some deliberate changes to dates etc., to compensate for a later Twilight War, whilst making the nature of the Twilight War nebulous, and attempting to drop the name "Twilight War," (which still appears six times in the book). The Twilight War now took place in the 2020's. Hence many events were shifted back about 20-30 years. However, dependent events did not, leading to effect happening before cause in places.

The other problem was revealed in a now deleted post by Colin - he is not referencing the source material as he is writing.

When Colin started writing his version of Invasion, he posted a snippet of what he'd written to the facebook group. It was less than awesome. Apart from nonsensical military tactics (akin to a fighter pilot in ACM landing their plane and then standing on the wing with their sidearm), and random gender swapping of established characters, he got basic facts like names of people wrong. When questioned, he admitted he doesn't check the original materials when writing, and simply writes what he remembers they said, and then never goes back to check. Hence the drift. Nothing is checked before the first draft is published (when those buying it get a chance to correct it before printing).

Take a simple thing, like the name of the American cruiser killed at Arcturus in 2299. Colin used my article on the Kennedy as his original source. For 2320AD he added some names for post 2301 ships, and in Mong he deleted some of them (inconsistently), and changed a few. However, the Sanchez wasn't on my list of active ships because she'd been destroyed, and so Colin never copied it over. Rather than looking it up, he made a name up. The other ship named in primary canon was the Jefferson, and she was one of those names that was deleted. Yes, neither of the ships that fought at Arcturus in 2299 exist in Mong 2k3. Oh, and amongst the names I made up, I got President Pemberton's first name wrong; I had 1st ed. Twilight: 2000, and Deanna Pemberton didn't get her Christian name until the 2nd ed., which I didn't own. Mea culpa.

Fig 1: Sorry boys, despite being heavily featured in GDW Star Cruiser and Invasion, you no longer exist.

So there we have an answer - nothing is checked, not even against the same book. Changes are made with no consideration of the consequences. Colin is following woozles. He made mistakes extracting things back in 2320AD, and he is now referencing that rather than the original source material. Further, he isn't cross-checking what he wrote (hence two or three different backstories for the Aconit etc.)

Future Work

I will write one more part on stutterwarp, examining the physics changes Colin has made. Combined  the two parts were at ca. 5,000 words. Then a piece on genetic engineering and the Pentapods. If I never get round to writing it, GDW's technology was realistic. Mong's really, really isn't. The Mongoose version of 2300AD is stuck in 

I won't get round to that this year though.

Missiles for MgT:2300AD Universe Redone to Match the Canonical Universe

MgT 2k3's Aerospace Engineer's Handbook has quite a few issues. One of the many issues is that the missiles are quite different, even in spirit, to the primary canon. Whilst I'm not completely wed to all the odder points of the primary canon, the missiles make no physical sense either. Most notably, nuclear warheads are depicted as being about 100 times larger than they are in reality. Also note that there is no possibility of the SR-10 in MgT ever launching a submunition in real combat, because it lacks the power output to fire the mass driver, use the guidance system and the engines at the same time.

MgT nuclear missiles are, apparently, simple nuclear blast explosives exactly like in Traveller. They use the same sort of rules. That's fine. It's a change in that universe. The missiles now also have some basic terminal guidance, which means they are actually "impacting" or at least being triggered by a proximity fuse. In the following, it is assumed that this is the case; the nuclear warheads are being detonated maybe a few tens of meters off the target. This creates some issues for submunitions, since they need to be dropped directly in the path of their target. However, as a nuclear proximity mine dropped by a fighter, it's still workable.

Warheads were scaled by taking the 4D, blast 8 of the SIM-14 as a 10x2, and doing linear scaling. The size of the warhead was reduced to 1% of the formula value, and this is about the right size for the warhead.

In the following the TL of a missile is taken directly from the TL of the drive in GDW. There is only one TL-12 missile in this selection, and that's the Ritage-2. Most missiles are TL-10 or 11. Some missiles are TL-9, and I've had to impute values. The date nations transition to New Military (TL-12) is in the 2270's for Britain, the 2280's for France, and the mid-2290's for America (with the Kennedy's starting to receive TL-12 drives to replace their old TL-10 ones from 2295 onwards).

I should note that adding sensors to MgT missiles is not at all viable, and those that had sensors in the canonical version, do not have them. Sensor drones as direct conversions are also problematic because there is no granularity in the system, and I can't put a 5 MW sensor on an HD-5, because such powerful sensors don't exist in MgT.

On traits, kinetic weapons (traveling at a few kps) and particle beams (traveling at ca. 10-25% of lightspeed) should not have the same modifier for not being speed of light..

Anyway, these are direct conversions from SC, excepting using batteries in place of the fuel cell (which has all sorts of advantages and simplifies matters), but keeping the power ratings. No missiles have sensors.

France

France has three missiles listed here. There is another in SotFA which is specifically for fighters. The Ritage missile is a particle beam armed (see the boxed set) drone, and so has no terminal guidance because it never impacts. Instead it is just a "remote turret" fired by the launching ship. The Ritage-2 is humanities top-of-the-line nuclear weapon. Most ships were originally fitted for Ritage-1's, but 3 Ritage-2's replace a Ritage-1. Thus, the missile armament of a Suffren or Richelieu is 48 Ritage-2's, with 3 replacing each Ritage-1. An Aconit frigate has 6 Ritage-2's.

The Ritage-2 was the biggest, fastest and most modern missile in 2k3, with the biggest warhead (tied with the SIM-14). This is literally a direct translation of that weapon, although I kept the MgT endurance of 3 hours.

The Silke is an obsolete weapon, used by second rate nations like Russia.

Ritage-1

• Nation of origin: French Union (2279)
• TL-11 (tail end of 11)
  
• Number in Service: between 1,000 and 2,000. Being sold off to allies cheap, as no longer a front line missile.
• Power plant: 0.1 MW TL-11 stutterwarp powered by batteries (16 hour life at 0.1 MW discharge, each shot of the armament drains 100 minutes from the battery)
• Sensors: none (fired from the mothership)
• Armament: 1 "2 MW" particle beam (3D, AP 2, EM, Slow)
• Speed: warp 3.09 (tac speed = 3)
• Hull: 1
• Tonnage: 2.5 dTons
• Cost: MLv 3.08

Ritage-2

• Nation of origin: French Union (2289)
• TL-12
  
• Number in Service: more than 1,000
  
• Power plant: 0.2 MW TL-12 stutterwarp powered by batteries (3 hour battery life at full power, attack modes may involve lower speed to increase range. Half-speed = 4x battery life)
  
• Sensors: terminal guidance, +1 modifier
  
• Armament: nuclear (4D, 8 blast, radiation)
  
• Speed: warp 8.6 (tac speed =9)
• Hull: 1
• Tonnage: 0.8 dTons
• Cost: MLv6.8

Silke (Silka)

• Nation of origin: French Union (2244)
• TL-10
  
• Number in Service: small numbers in many second rate navies
  
• Power plant: 0.1 MW TL-1 stutterwarp powered by batteries (1 hour battery life at full power, attack modes may involve lower speed to increase range. Half-speed = 4x battery life)
  
• Sensors: terminal guidance, +1 modifier
  
• Armament: nuclear (2D, 4 blast, radiation)
  
• Speed: warp 4 (tac speed =4) - limited by TL from 5.54 (tac speed = 6)
  
• Hull: 1
• Tonnage: 0.7 dTons
• Cost: MLv1.59

Germany

The Federal Republic of Germany primarily used Ritage(-1) missiles in 2291. After the German revolution, the 4th German Empire was unable to purchase Ritage-2 missiles from France, and so had to improvise. They had the facilities to manufacture Silka missiles due to an ongoing contract with Russia (who added the warhead), and had hundreds of Ritage-1's captured from the Federals. The Silka units had a small nuclear warhead installed in place of the Russian one and were fielded as SR-9. The Ritage's had a larger warhead installed with a terminal guidance package and were fielded as SR-10. As highly improvised missiles, manufacture did not progress once stocks were used, and the 4th German Empire finds itself rather short of missiles.

 SR-9

• Nation of origin: 4th German Empire (2291)
  
• TL-10
  
• Number in Service: no more than 100.
  
• Power plant: 0.1 MW TL-10 stutterwarp powered by batteries (2 hour battery life at full power, attack modes may involve lower speed to increase range. Half-speed = 4x battery life)
  
• Sensors: terminal guidance, -1 modifier
  
• Armament: nuclear (1D, 2 blast, radiation)
  
• Speed: warp 4 (tac speed =4) - limited by TL from 5.59 (tac speed = 6)
  
• Hull: 1
• Tonnage: 0.7 dTons
• Cost: MLv1.01

 SR-10

• Nation of origin: 4th German Empire (2291)
  
• TL-11
  
• Number in Service: estimated between 100 and 200.
  
• Power plant: 0.1 MW TL-11 stutterwarp powered by batteries (2 hour battery life at full power, attack modes may involve lower speed to increase range. Half-speed = 4x battery life)
  
• Sensors: terminal guidance, no modifier
  
• Armament: nuclear (2D, 4 blast, radiation)
  
• Speed: warp 6 (tac speed =6) - limited by TL from 6.49 (tac speed = 6)
  
• Hull: 1
• Tonnage: 0.6 dTons
• Cost: MLv1.80

Manchurian Soviet

Manchuria is the state created by the Soviet Occupation of 1995, although Soviet control has since broken down. It is quite backwards, with a general naval TL of 10.

Glowworm

• Nation of origin: ex-Soviet Manchuria
  
• TL-9
• Number in Service: ?
• Power plant: 0.1 MW TL-9 stutterwarp powered by batteries (12 hour life at 0.1 MW discharge, each shot of the armament drains 40 minutes from the battery)
• Sensors: none (fired from the mothership)
• Armament: 1 LL-88 laser (1D)
• Speed: warp 3.0 (tac speed = 3) - limited by TL from 3.32
  
• Hull: 1
• Tonnage: 1.6 dTons
• Cost: MLv1.58

Fan Tan

• Nation of origin: ex-Soviet Manchuria
  
• TL-10
  
• Number in Service:?
  
• Power plant: 0.2 MW TL-10 stutterwarp powered by batteries (2 hour battery life at full power, attack modes my involve lower speed to increase range. Half-speed = 4x battery life)
  
• Sensors: terminal guidance, -1 modifier
  
• Armament: nuclear (2D, 4 blast, radiation)
  
• Speed: warp 4 (tac speed =4) - limited by TL from 5.59 (tac speed = 6)
  
• Hull: 1
• Tonnage: 0.7 dTons
• Cost: MLv 1.68

American Republic

The American Republic is just reaching TL-12, with the refit of TL-12 engines onto the Kennedy beginning in 2295. The SIM-14 is an aging missile with a large warhead and an OMS thruster, which no-one has ever found a use for.

SIM-14

• Nation of origin: American Republic
  
• TL-10
  
• Number in Service:?
  
• Power plant: 0.07 MW TL-10 stutterwarp powered by batteries (8 hour battery life at full power, attack modes my involve lower speed to increase range. Half-speed = 4x battery life)
  
• Sensors: terminal guidance, -1 modifier
  
• Armament: nuclear (4D, 8 blast, radiation)
  
• Speed: warp 3.77 (tac speed =4)
  
• Hull: 1
• Tonnage: 1 dTons
• Cost: MLv3.79
• Other: OMS (2 burns)