This page was last updated on 1 January 1998.

Thoughts regarding an advanced variant of Avalon Hill's Stellar Conquest

On the theory that if I wait until I finish this project I'll never get to play it, the following are some ideas I have for modifying AH's Stellar Conquest. It should become clear, however, that these modifications would change the game to such a large degree that it would, in effect, be an entirely new game, even if played on the Stellar Conquest mapboard.

Please note that I am not suggesting that all of these ideas are worth pursuing -- some of them are even contradictory.


In general, I see three basic ways of approaching the problem. The first involves only tweaking those parts of Stellar Conquest that are the most broken, with an eye towards minimizing the changes. I call this the minimalist">Minimalist version.

The second approach involves keeping the basic Stellar Conquest framework, but rewriting large parts of the current rules. I call this the Maximalist version.

The final approach is basically my proposal for taking the Stellar Conquest mapboard and the general information available on the system cards and essentially abandoning the rest of the game (combat, economics, etc.) in favor of a variety of ideas found in Prism's Throneworld and Twentieth Century Renaissance's Gateway to the Stars. I call this the Radical version.

Please note that the desire to take one approach doesn't necessarily invalidate the others. I don't simply mean this in terms of "everyone is welcome to their own preferences" -- I would like to see all three approaches developed, and would probably prefer to play the Radical version face-to-face, but the Maximalist version for play-by(-electronic)-mail play.

Special thanks to Torben Morgensen, whose Stellar Conquest variations document can be found through Web-Grognards. Many of the ideas (and some of the basic prose) in the Minimalist section come from that document. Such points are marked [TM].

Why do any of this? What's wrong with the current game?

In my opinion, Stellar Conquest is a great game for two reasons. First, when it came out in 1974 it was one of the first "space empire"-type games on the market. It essentially created the market. Second, in the process it introduced a lot of innovative new concepts (e.g., tech research, population and colonization) -- concepts that have since become standard components and any space empire game. The entire space empire genre owes a heavy debt to the designers of Stellar Conquest.

That having been said, I would argue that Stellar Conquest is not a great game to actually play, for the following reasons:
  • The combat system is somewhat flaky, with fighters rolling two dice but hitting on only "10s", etc.

  • The technological research system is too predictable. Even with radical new technologies, you know exactly how many resources it will take to achieve breakthroughs.

  • The technological system is too specific. There are only a limited number of options available for the players.

  • Planetary shields allow the creation of invulnerable Death Star factories.

  • The population system is prone to abuse. Becuse of the way the population rules work, people end up shuffling population factors around to avoid arbitrary die-offs. This leaves people spending a lot of time worrying about relatively trivial details.

  • The population system is very detailed about population numbers, but does not account for all the non-population factors that go into economic production.

  • There is too much paperwork overall. Stellar Conquest is a game for accountants.
Now, these are certainly prone to argument, and that's fair; I think even the most die-hard Stellar Conquest fan, however, would see the need to tweak some of the rules.

Minimalist Version

In general, the Minimalist version would seek to fix the bugs without changing the flavor of the game. I see the following changes being made in the Minimalist game:

Planetary shields

"Planet Shields are changed so that don't give full protection for a planet, but merely have the combat abilities of a Death Star with Improved Ship Weaponry, except that the two attacks may be split up to attack two ships. You can buy as many Planet Shields as you want on any planet. The cost of research is only 100 if you have Advanced Missile Base.

"Why: Planet Shields as they are make extended play scenarios impossible. I also dislike the idea of perfect defenses, but that is a personal opinion."[TM}

Technological research

Tech research would be made a little less predictable by adding a die roll to the process. Players would purchase die rolls, and the tech reserach cost of an item would be the total number of pips that needed to be rolled. This could be either a straight amount, never varying, or it could change depending on how many dice were being rolled, and whether this was a newly started research project or a continuation of an old project.

For example: Normally, a die worth of research would cost 5 IPs -- in other words, you pay 5 IPs, roll the die, and the total on the die gets added to the total accumulated "research points," and when the total equals or exceeds the cost of the item, it has been developed and can be used according to the rules. The turn a new research project starts, however, the first die costs 10 IPs. This represents the normal start up costs associated with any new project.

If a production turn passes without continuing research, the points rolled are retained, but the next roll must pay the higher (10 point) cost, as the project has been without funding and must acquire new staff, equipment, etc.

If you wanted to, you could also add in the idea of diminishing returns for extra resources added onm any particular turn. That 5 IP cost assumes that you are rolling one die each turn. You can roll more than one, but each extra die costs more than the one before it -- this represents the idea that while you can throw more resources at a project, they won't always be efficiently used. This may or may not be needed -- by going to the die rolling system, you are already slowing down technological development a bit, since a die roll notionally costs 5 IPs, yet the average die roll is less than 5.

If you do want to go with the diminishing returns idea, I suggest the following:

  • 1 die = 5 (base)
  • 2 dice = 12 (5 + 7) [base + (base + 2)]
  • 3 dice = 21 (5 + 7 + 9) [base + (base + 2) + (base + 4)]
  • 4 dice = 32 (5 + 7 + 9 + 11) [base + (base + 2) + (base + 4) + (base + 6)]
Note that if the base is higher (because it is the first research turn), the follow-on costs are higher as well.

Population and colonies

  1. One of the most irritating things about Stellar Conquest is the arbitrary population die-off that occurs if you exceed the planetary limits. I would much rather see either of the following:
    • Population over the population threshold do not produce IPs.

    • Every one million population over the rated population maximum of the planet produces 1 IP of production as normal. The upkeep of that population, however, costs 2 IPs. In other words, every million persons over the population threshold results in a net cost of 1 IP per production turn.
    The first rule would have the effect of removing the necessity of moving excess population immediately while retaining the economic incentive to do so. The second rule would strengthen that incentive, to the point, actually, where it may not be any different than simply letting them die.

  2. "The emigration population bonus should be disregarded. Instead, roll a die every production turn. The result is added to the population of all inhabited planets on the board for purposes of calculating population increase only.

    "Why: The original bonus rule is inavariably misunderstood by new players, and led to a lot of moving colonists back and fourth between already established colonies. The die roll makes small colonies grow relatively faster than large ones, which gives a reason for colonizing new worlds before your old ones are full. The roll also prevents moving small numbers of colonists around to make sure all planets have populations that are exact multiples of 5." [TM]

Robot industry

"Robotic Industry is changed so it doesn't allow unlimited numbers of factories, but has a limit of 4 per million population.

"Why: If there is no limit to the number of factories on one planet, there is no reason to have more than one industrial world, and the small mineral rich planets become uninteresting. With the standard versions of Robotic Industry and Planets Shields you can have a steadily growing, totally unstoppable Death Star factory. If a player can find the one Minimal Terran 40 Mineral Rich planet in the game early on, he is certain to win if he puts all his colonists down on it." [TM]

Combat system

"Fighter ships and Advanced Missile Bases are given a 1-3 (rather than 1-2) chance to destroy a Corvette or Missile Base.

"Why: Statistical calculations show that a combat between fleets of Corvettes and Fighters of the same total cost is heavily in favor of the Corvettes. This is especially true when the ships have Improved Ship Weaponry." [TM]

Command posts and ship range

"Unlimited Ship Range should be replaced by Ship Range 12 Hexes, with cost etc. otherwise the same.

"Why: So Scouts and Command Posts don't leave play. It also allows for some tactical tricks, like destroying an enemy fleet by conquering the world with the Command Post they use." [TM]

That's about it for the Minimalist ideas that come immediately to mind. In all honesty, the Minimalist approach is not the one that I would choose.

Maximalist Version

Overall, the Maximalist approach would involve rewriting some of the core sections of the rules (e.g., the combat rules), but would still be recognizable as being Stellar Conquest. As such, it would probably be most deserving of the name Advanced Stellar Conquest.

Planetary shields

Each shield has a certain number of hits it can absorb. Each turn the besieging player allocates a certain amount of capability to attacking the shield. After the shield absorbs that number of hits, the shield falls, and is hence vulnerable to capture/destruction. [More details in the Combat systems section.]

This is inspired by the planetary shields in the Exordium series, which work by transferring the energy of the attack to planet itself -- eventually, the planet must capitulate or suffer tremendous earthquakes.

Technological Research

Tech research would could either use the Minimalist tech research system outlined above, or something more radical, such as replacing the research system with a "resource/research" deck, such as used in Supremacy. For those who haven't played Supremacy, it works something like this: There is a deck of cards which includes different resources AND technological improvements. A player declares he is going to research a particular innvovation (or mine for a resource), and begins flipping cards over. Each card flipped costs a certain amount of money. The player may keep flipping until he find the card he has announced he is searching for, or he may stop at any time. Either way, he must pay for each card flipped, even if he quits the search before he finds the card for which he is seeking.

In some ways this would be a great way to do this, because it would also provide a mechanism for resource aquisition as well. (In fact, I think the Supremacy could be converted into an interesting space empire game, but that's a subject for another page.) It would require coming up with a deck of cards, which not only is more work than I want to do right now, but (if done right) potentially expensive as well.

Another alternative would be a technology like that in Prism Games' Throneworld. I think this would work better in a Radical version, though, so I'll cover it there.

Population and Colonies

Use the Minimalist alterations.

Robot industry

Use the Minimalist alterations.

Combat system

Either use the Minimalist alterations, or preferably one of the following:
  1. Offensive combat strength is based on die roll, defensive combat power is fixed;
  2. Offensive and defensive combat strength is based on die roll;
  3. One combat strength rating, which is based on a die roll.
Here are some sample numbers, using d6s:
Ship Type Attack Value
(1, 2, &3)
Defense Value
Defense Value
escort d6 3 d6
destroyer d6+n 5 d6+n
light cruiser 2d6 7 d6+n
heavy cruiser 2d6+n 9 2d6
battle cruiser 3d6 9 2d6
battleship 3d6 11 3d6
deathstar 4d6 18 3d6+n
  • n varies per ship type (and maybe tech level);
  • Battle cruisers: attack strength of a battleship, defense strength of a heavy cruiser;
  • Some ships (e.g., deathstar) are multi-step units.
This system has several advantages over the current Stellar Conquest combat system, including that it integrates well with the Maximalist idea listed above regarding planetary shields. It also allows for big ships to be overwhelmed by small ships (which can't happen in regular Stellar Conquest), but it make's it bloody for the small ships in the process.

Some ships have defensive values large enough that certain ships types can never have an attack value large enough to beat them. Maybe they could gang up on the larger ship, using a combined attack value determined by the formula:

AV = A plus d6 plus (N-1), where N = number of ships attacking.

If dissimilar ships are attacking, the SMALLEST value of A is used.

The target may fire back at each attacking ship. This shot could be at full strength, or using a formula like the following:

AV = A plus d6 plus Na, where Na starts at 0 and decreases by one for each ship.

Ship A: AV= 6+d6 DV= 10
Ships W-Z: AV= 3+d6 DV= 4

W-Z firing on A: AV = 3 + d6 + 3 = 6 + d6
A firing on W: AV = 6 + d6 + 0 = 6 + d6
A firing on X: AV = 6 + d6 + -1 = 5 + d6
A firing on Y: AV = 6 + d6 + -2 = 4 + d6
A firing on Z: AV = 6 + d6 + -3 = 3 + d6

This allows small ships to "gang up" on larger ships, but guarantees the price will be high, and mandates that they must act in concert.

Shipyards and Ship Construction

Building a ship requires a shipyard. This idea is pure chrome.
  • Command posts could represent shipyards, which would be a separate cost -- the tech ability to build destroyers, for example, means that you have the ability to upgrade a particular shipyard to build destroyers. Command posts/shipyards would originally only have the ability to construct scouts.

  • To build a vessel, a system must first invest in the necessary infrastructure. This is a one time cost equal to the cost of the ship being built.

  • The shipyard must be capable of building lesser ships. (Example: A planet would like to build battleships, but in the past has only built cruisers. The player would have to upgrade the shipyard to build both battleships and cruisers.)

  • Maybe some restrictions on the number of upgrades allowed in one turn, i.e., you can not go directly from destroyers to battleships.

  • Add a research and development chart for command posts/shipyards technology. "With previous" means upgrading an existing command post, new level means building one from scratch.

  • Cost to build a ship = # of turns necessary to build it (1 point spent per turn).

  • Sheet with shipyard build tracks on it.

  • Total capacity = largest ship capable of being built, per turn. It would be possible to have more than one shipyard at a particular location.

    • Example: shipyard can build a ship of cost 6.

    • Each turn, 6 construction points can be spent in the yard.

    • Each construction point spent will move 1 ship forward one box.

  • Partially built ships can sit idle.

  • You cannot start a ship greater than the capacity of your yard, even if you plan to increase the capacity of the yard to complete construction. (Example: Capacity 6 yards can't start capacity 8 ships, even if you plan to increase the yard to capacity 8 to finish it.)

Command Range/Refueling

I've always thought that the command rules in the basic game are somewhat arbitrary. Here are some alternatives.
  • Range is counted from the departure stellar system, not Command Post, and represents a ship's unrefueled range.

  • Refueling takes place at gas giants in the target system.

  • At the same time the system characteristics are determined, a gas giant presence determination would be made. Current astronomical thinking is that gas giants are needed for earth-type planets (to clean up the junk that would otherwise keep hitting the planet).

  • Most systems have gas giants, but some do not. Scouts have enough fuel to return to base if no gas giants are found. Warships would be trapped in system. The "unknown danger" roll for scout ships exploring a new system would be eliminated.

  • New ship class: tanker. This functions like the tankers in GDW's Imperium, processing fuel from the stellar atmosphere.

  • Alternatively, stellar systems could be something like GDW's stutterwarp discharge points; if so, then some mechanism for finding brown dwarf stars in otherwise unoccupied hexes might be necessary.

Radical Version

The Radical approach I'm proposing here would basically take a couple of ideas from Stellar Conquest and create a new game, which would use the Stellar Conquest map.

Population and Economics

Population and economics would be based on the system used in Twentieth Century Renaissance's Gateway to the Stars. Gateway. abstracts population into the habitability rating for the system and the current number of Total Colony Forces (hereafter TFs) already present. A player builds Colony Expeditions (identical in concept to a Colony Transport in Stellar Conquest), which are converted into TFs during the Colonization phase. The number of Colony Expeditions required to create a TF is equal to the habitability of the system (which ranges from 1 to 6) and the number of TFs already there. A system with habitability 2 and 4 TFs present, for example, requires a total of 6 new Colony Expeditions to create the fifth TF, yet that fifth TF produces the same number of credits per turn as the first. This does a good job of simulating the diminishing marginal utility of adding more colonies to a system.

For the Radical alternative, the basic information from the star cards would be distilled into a habitility rating. Some systems should have a habitability rating less than one. This allows "gardenworlds" to sustain very high populations, and brings the system more in line with the feel of Stellar Conquest. Systems with a habitability rating of less than 1 would be treated as having a habitability rating of 1 until the total number of colonies was equal to the absolute value of the habitability rating. In other words:
IF [habitability rating + #colonies already in place] is less than 1,
THEN #TCFs necessary to create a colony = 1,
ELSE #TCFs necessary to create a colony = [habitability rating + #colonies already in place]

Perhaps each system should also have an economics rating, based on the presence of mineral rich worlds, with the total production being determined by [total colonies x econ rating].

The habitability rating would be determined by a chit appropriate to the color of star being explored, which would either be drawn when exploration takes place, or would be placed before the game starts. The values on the chits would be derived from the values used in the Stellar Conquest system cards.

Technological Research

Technology would be based on a technology track like that in Prism Games's Throneworld. This track consists of a number of boxes attached linearly. At the top of each box is a number, which indicates the tech level of the specific chits in the box, with some of the numbers repeated in more than one box. Between each two boxes is a number with a plus sign; to advance to the next box, you must roll equal or greater than that number. Some Throneworld technology tracks also have a number of the bottom of each box; this is used for races with special technological advantages.

For our purposes, there would be four different technologies: COMM, JUMP, SPACE and GROUND. Each has a chit, with an upwards-pointing arrow (except as below). SPACE and GROUND tech ratings will be explained below, in the discussion regarding combat systems. COMM defines the range that ships may travel from Command Bunkers; the number listed on the chart plus 6 would be the current COMM range. JUMP plus 2 defines the current maximum speed, in hexes per turn. This gives COMM and JUMP ratings equal to the capabilities of ships at the beginning of Stellar Conquest. Alternatively, rather than adding a number to each chit, those technologies could have their own tech tracks, or they could use downward-pointing arrows which point to another set of numbers.

Once a turn, players would be able to conduct technological research, which is done by picking a technology and rolling a die; if the number rolled is greater than or equal to the number in between the boxes on the technology track, the chit is moved on box to the right, and the number the arrow is pointing towards is the current tech level. Note that the tech level may not have increased, as almost all tech levels have multiple steps before advanacing to the next level. In addition, the number to be rolled increases with the tech level, meaning that early advances are relatively easy, while later advances get tougher and tougher.

Throneworld also includes a mechanism whereby alien artifacts are found and extra tech rolls may be made; a similar mechanism could be used here.

[For a further explanation of the Throneworld technology rules, including an illustration of the tech track, please see my Throneworld page.]

Combat System

The Combat system would be based on the Space and Ground combat system found in Throneworld. There are several types of Space and Ground units in Throneworld, with the following attributes:
  • Each unit rolls a certain number of dice (between 0 and 3) when attacking;
  • Each unit rolls a certain number of dice (between 1 and 3) when defending;
  • Hits are recorded on a to-hit basis, with the base being that the a unit hits when a "6" is rolled;
  • If one side has a technological advantage (i.e., that side's SPACE or GROUND chit, as appropriate, is on a higher tech level on the tech track), the difference between the two is used as a die roll modifier. The lower tech side continues to hit on a roll of "6";
  • Each SPACE unit either provides carrying capacity or requires a certain amount of capacity to be used to carry it. Each GROUND unit requires a certain amount of capacity to be used to carry it;
  • Each unit has a number of steps (i.e., number of times it can be hit before being destroyed) between 1 and 4.
Combat begins when two opposing space forces are present in system. Each round of combat is simultaneous; casualties are removed between rounds. Shield units can absorb one hit, and have defensive fire. Other units involved the equivalents of carriers, battleships, cruisers, and scouts.

If the invading force is successful in defeating the defender (either through forcing a retreat or outright destruction, ground forces may be dropped on the planet, and the entire process is repeated. If Drop forces are carried, they may invade after the first round of space combat.

One of the advantages to the Throneworld-type system is that all the combat for a particular round can be rolled at once; all of the other proposal on theis page, and vanilla Stellar Conquest as well, require each ship to be rolled for separately.

Neutral Systems

Neutral systems in Throneworld have a system chit, which describes the development value of the system, its SPACE and GROUND tech levels, and the space and ground forces present. [In some cases these values may all be zero, indicating the system is not inhavited.] As a result, acquiring systems is not usually just a case of getting there first -- you usually have to conquer the locals. This system could be used, either by placing these chits on the board at the beginning, or by conducting an exploration roll whenever a system is first explored.

Overall, this is a game I would like to do, and which I think would be relatively easy to put together.

Feedback is encouraged -- please feel free to email me with any questions, additional ideas, et cetera.