The solar system consists of 12 planets, each of them surrounded by six grid points where battle stations may be placed. Some grid points border several planets, hence making their battle stations more powerful. You claim a planet if you have the most battle stations at the end of a round. You win if you claim 3/4/5 planets (5/4/3 players).
Each round you compete for the next planet in order. You do so by playing cards representing either two forces (black) or one force (white). One black card may be played each turn together with none or one white card. The black cards must follow suit while the white cards may be played together with any suit.
When you pass you take the tricks of all forces with a majority and places one battle station for each trick. Also, an early pass gives you an early pick of new cards from a drawing row. However, it makes the remaining tricks easier to get for the other players.
When the round ends, you claim the planet if you have the most battle stations around it. Also, any previous planets that were tied in previous rounds are reassessed to see if the majority has changed. (Remember that a battle station may reach more planets.) One of the tricks allows you to change the order of the planets to take advantage of well positioned battle stations.
0.6: 7 cards at start, stargate trick optionally awards 2 random cards
0.5: 2 player variant added
0.4: Turn order based on retire order, Martian ability limited to 1 grid line
The complete rules are available in the PDF file to the right. In the following sections, I will describe how they came
Battle stations and grid points
What's the perfect ratio between the number of battle stations placed and the number of grid points available? Initially I assumed that it should be 1 to 1 and started with square planet cards with 4 grid points and 4 forces. As I moved on to hex planet cards, I realized that 6 forces would be too much, since it would almost guarantee 1 battle station for each player but also that it wasn't necessary that all grid points get occupied in a round. With abundant grid points, it's less important to pass first to get the most valuable grid point and the players may focus on getting as much return on their cards as possible instead. A good example of how testing may dictate design decisions.
Battle stations on same grid point
The mechanism of grid points covering several planets will necessarily lead to more battle stations than available grid points. Hence, it must be possible to place several battle stations on the same grid point. But if the players know the planet of the next round, won't they all place their battle stations on the grid point adjacent to that one? This would lead to clusters of battle stations, where it's difficult for a player to position himself or herself for a majority. Forcing them to place on different grid points in the same round (but allowing them to place on grid points placed on a previous round) would result in a more interesting network of battle stations.
The fifth force: The Stargate
Besides good card management, timing is important to get your battle stations where you want them. If you know the order of the planets, you know when to spend and when to save cards or which grid points to occupy to be well positioned for the next planet. Those basic strategies highlighted another strategic opportunity: what if a player would have the power to choose the next planet? This reasoning led to the addition to the four "ordinary" forces used to place battle stations: the Stargate used to change the order. However, to avoid too much chaos, e.g. the planet you expect to be resolved last is suddenly resolved now, this power was was mitigated by letting the player changing only planets in succession.
The planet tie breaker
The tense nature of the game, where the players can be expected to claim 1 battle stations each in each round, make ties around planets likely. Initial ties are good, since this gives the players the opportunity to come back and break them when adjacent planets are resolved, but isn't there a risk that the ties remain even after that? A simple but yet thematic solution was to use the classic "longest road" mechanism and reward players who manage to connect their battle stations. The more connected battle stations, the more likely can ties be broken in your favor. In practice, ties turned out to be less common than expected but the mere fact that the rule was there contributed to this.
The game tie breaker
The tense nature of the game makes it even more important to find a good tie breaker that not only mitigates the risk of ties but also is in line with the goal of the game. With only 12 planets at stake, it's more than likely that several players will end up with the same amount. One idea was to simply count the cards in different ways but why should card hoarders be rewarded? A better idea was to continue to do what you did in the game: play out your cards to win tricks until one single player claims the most tricks. That would still reward card hoarders but only if you've hoarded the right cards and play them well.
... and Rejected Rules
There are of course also ideas that will be rejected and here I will explain why.
Grid points linked to force symbols
Should a grid point be linked to a specific force symbol, forcing the winner of the force trick to place there? This rule would put emphasis not only on getting the right suit of cards but also on getting the right symbols. On the other hand, it would remove much of the tension on the board, as the players wouldn't be able to choose where to place their battle stations but rather be played by their cards.