Wargame Wednesday – Imperium Take Two

In preparation for my Second Interstellar War using GDW’s Imperium, I was doing my customary rules review when I noticed a few rule nuances concerning Maintenance, Planetary Defensive Fire, and Surface Combat that I missed in my first go-around last year. The rules are important enough that I decided not to go to the Second Interstellar War but restart from the beginning.


This time I really paid attention to the Economic Rules, given my somewhat recent attention to the IMTU Arden background I am developing. Specifically, I was trying to see what lessons/inspiration I could draw from the RU (Resource Unit) approach to economics that is used here in Imperium as latter in T5. The budget system in Imperium with RUs is different than Traveller Adventure 5: Trillion Credit Squadron and Power Projection: Fleet which uses Credits as their currency.

I discovered I played Maintenance totally wrong. Maintenance represents “expenditures…necessary on a recurring basis to ensure that ships remain functional and in fighting trim” (Rule Book, 12). Basically, Maintenance is paid by turn (each turn representing two years) in one of two ways:

  • Civilized Maintenance is paid if a ship is in a primary system with a friendly world marker; the player expends RUs equal to the maintenance number for the ship
  • Frontier Maintenance applies in all other situations; the player rolls 1d6 and must be equal to or higher than the maintenance number to be successful – unless there is no friendly outpost present in which case a +1 modifier is added to the die roll; missing the maintenance roll results in a disrupted ship.

Players really want to avoid disrupted ships. A disrupted ship must roll its maintenance number or higher to move and it subtracts one from any attack die rolls or when defending against planetary defenses. To become undisrupted, at a friendly world the players pays RUs equal to the maintenance number plus 1 or in all other conditions the player must roll higher than the maintenance number.

Maintenance has a tremendous impact on fleet budgets and deployments. If a player keeps all his ships in a primary system world, he pays directly from his budget for maintenance. Far better to keep your ships at outposts and pay nothing, right? The catch here is that ships using Frontier Maintenance have a better chance of breaking down .

Take for instance the lowly Scout. With a maintenance number of 1, it is always ready if at a friendly outpost and even if in unfriendly space it only has a 1 in 6 chance of disruption. A Heavy Cruiser (CR) with a maintenance number of 4 has a 50% chance (3 in 6) of being ready if at a friendly outpost, but only a 1 in 3 chance if in unfriendly space. The worst is the Dreadnought (Imperial B1/Terran B) with a maintenance number of 6! If at a friendly outpost there is only a 1 in 6 chance to avoid disruption, and if in unfriendly space there is no way at all to avoid being disrupted. Remember that to undisrupt a Dreadnought it will take 7 RU at a friendly world; there is no way to undisrupt it elsewhere since you have to roll higher than the maintenance number of 6 – impossible on 1d6. If you really need this ship, better to station it at a Primary System World, but that means paying 6 RU per turn (Civilized Maintenance) to have it standing by.

So the player has to chose between having ships at the ready, but paying directly from the budget, or paying less maintenance but risking disrupted ships. The practical impact is that larger ships will tend to be based at at primary worlds to be “at the ready” whereas smaller ships will depend on Frontier Maintenance at friendly outposts.

HALO ODST Drop Pod (Megabloks)

Planetary Defensive Fire

I totally missed the difference between Jump Troops and Regular Troops when it comes to Planetary Defensive Fire (Rule Book, 8). Since a Jump Troop can be inserted from space, the Jump Troop is subject to planetary defensive fire but the transport is not! The obvious impact is that the useful Transport can be protected.

Surface Combat

Two aspects of Surface Combat (Rule Book, 8-9) also caught my eye. First, I totally missed that starships can participate in Surface Combat! This is because when terminating space combat (Rule Book, 7) there are some ships that could be left behind:

“Ships which cannot perform hyperspace jumps (monitors, fighters, reaction forces which have already jumped three times, and disrupted starships unable to make the required die roll) are left behind to carry on the battle alone.”

The attacker then gets to conduct Planetary Bombardment using World, Outpost, and Planetary Defense markers for Planetary Defensive Fire. This is followed by Surface Combat.

I guess I got caught up in thinking of Surface Combat as just that; troops versus troops. But in reality it goes beyond that simple view. As stated in the rules, “If the defender has fewer troops than the attacker, the defender must now move forward non-troop counters (planetary defense markers, ship counters, and lastly world or outpost markers), each to be matched by an attacking troop counter.” There is an implied priority here; first used to defend are planetary defense markers or ships (monitors, fighters, and disrupted ships) and secondly outpost or world markers. The rules even specify that planetary defenses defend at a factor of 2 but all others (including starships) defend with a factor of 1.

The second nuance I missed is Defensive Fire (Rule Book, 9). Given that Jump Troops are “lightly equipped,” they are at a disadvantage against Regular Troops which include heavy artillery (Rule Book, 11). Regular Troops get a defensive firing that could destroy the Jump Troop before it even gets a chance to fight! Really makes for an interesting budget and strategy decision; pay 3 RU for Regular Troops (1-4 combat factors and Transport risked) or 2 RU for Jump Troops (4-6 combat factors but less risk to transport yet vulnerable to defensive fire).


Every time I play Imperium I get a greater appreciation of the depth of economics as well as strategy and tactics that are in this seemingly simple game. Simple it that the rules are really uncomplicated (I just have to read them better) but represent a very complex set of interactions making for a fun and thoughtful gaming experience.

“The Traveller game in all forms is owned by Far Future Enterprises. Copyright 1977 – 2012 Far Future

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