(written by Veldan)

Welcome to this first article in a three-part series discussing an oftentimes not well-understood subject in Planets: the lowly minefield. This series of articles is intended to cover major subjects for minefields. This first article introduces the minefield, outlines its major characteristics, gives guidance on how one may consider moving through a minefield, explains the minefield limit, and finally describes the relationship between a minefield and that scourge of the Echo Cluster, the ion storm. This article is directed toward new players, but it is my hope that players of all skill levels will find the information contained within useful.

“Mines, mines everywhere!”

Take a look at many advanced late-stage games and you will find one common factor: the entire map is peppered with mine fields. They help form the backbone of most runs toward victory. This is because the minefield enables several functions critical for any commander. First of all, the basic map is formless with clusters and strings of planets laid out, but they are approachable from any direction by any player. Minefields create obstacles to cross and allows a player to define the battlespace. The player who defines that battlespace can often dictate the mission of the ships within and decide how material and reinforcements may be moved. In short, a minefield is a tool for domination and control of the battlespace.

To begin a discussion of space mines, it is best to go back to the original source material.  The original explanation of space mines come from Tim’s Docs;

“A minefield is a small area of space that is peppered with warheads that track and launch themselves at passing enemy ships that are unlucky enough to trigger one of them.

Minefields are formed when a starship with torpedoes chooses the mission Lay Mines. All the ship’s torpedoes are taken apart by the ship’s chief engineer and reprogrammed to serve as deep space mines. High tech torpedoes are divided into several smaller units that can cover a greater area of space.”

Tim then goes on to explain everything about how mine fields work, but he leaves some basic questions on the table. One of those questions is, “What identifies a minefield as being a unique object on the map?” The answer to that is:

The Nine Attributes of Space Mines

A minefield has nine distinct characteristics that make it unique. These characteristics determine the behavior of that specific minefield.

1. Type of Mine Units — During clientside actions the player may choose the “Lay Mines” mission or the Crystal may also choose the “Lay Web Mines” mission, both missions convert torpedoes into minefields, just very different minefield types. The “Lay Mines” mission occurs before the “Lay Web Mines” mission during hosting. Both missions progress through the ship list by ship ID number, where the lowest ID ship lays first.
2. Center — The center (x,y) coordinate of a mine field is determined by the location of a ship during the mine laying phase in host. If a ship attempts to lay mines within a mine field it will most likely add to that minefield. Keeping track of center points is essential when attempting to overlap minefields.
3. Minefield ID — Minefields have a unique ID number. Minefields with lower ID numbers react against enemy minefields first.
4. Player ID — A minefield is owned by the player that owns the ship performing the mine laying mission, unless that ship uses an mi(x) friendly code.  The mi(x) friendly code will allow all of the mines on board a ship to be laid in any other player’s identity.
5. Number of Units — This is a simple function of (weapon slot of the torpedo) ^2 * (number of torpedoes) = (number of units laid). Robots laying mines in their own identity lay four times this number. The number of torpedoes used to convert into mines can be changed through the md(x) fcode.  Where x is equal to 0-9 and the characters of “q”, “h”, and “a”.  The characters mean “quarter”, “half”, and “all” respectively.  “All” is always assumed if no friendly code is used.  1 – 9 are multiplied by 10 torpedos, and 0 equals 100 torpedoes.  A single minefield can contain no more than 22.500 mine units.
6. Radius — This is a simple function of sqrt(number of mine units) = radius. All mine units are distributed evenly throughout a single minefield.
7. Nearest planet owned by Player ID — This is used to determine what planet controls the friendly code of the minefield.
8. Minefield Friendly Code — This value is set several times during the host cycle. When a minefield is first laid, it has no friendly code. The friendly code for a new minefield is determined after the mines destroy mines phase.
9. In Ion Storm radius (yes/no) — A minefield whose center is within an ion storm is invisible and cannot be swept except by the Missing Colonies of Man, using their ability of fighters to sweep mines.

Moving Within Mines

Most movement within a minefield carries with it a percentage chance to hit a mine.  The statistical probability of not hitting a standard mine in a single minefield is equal to 0,99^(total ly travelled) if uncloaked, 0,995^(total ly travelled) if cloaked, and 0,95^(total ly travelled) going through a web field.  It is up to each player to determine their own level of acceptable risk when travelling through mine fields.  To have a very good breakdown of the math behind these equations, read the wonderful article “The Theoretical Probability of Hitting Space Mines” by Alejandro M. Dobniewski.

The Mine Field Limit

There is a minefield limit in Planets brought on by new game configurations that became mature in the summer of 2012. It was identified that having more than 500 minefields (a traditional limit) was turning some games like Giant Melees and Team games into unmanageable messes. A “soft” minefield limit of 500 was implemented. When a sector reaches 500 minefields, some will begin to be removed with the following guidelines:

• The smallest minefields will be removed first, but only those minefields with no enemy ship within 200ly.
• A new minefield will not be removed the turn it is laid.
• The mine field limit may be exceeded if no mine fields match the above two constraints.

Ion Storms

Ion storms have two unique effects on minefields. As pointed out in the 9 attributes section, a minefield that has its center point within the radius of an ion storm is cloaked from mine sweeping, except for Colonial fighters. A second effect is useful for ships in a class 4 or 5 ion storm: a ship being dragged by an ion storm will not hit a mine. However, this only applies to the dragging effect: if a ship then moves during the regular movement phase and it is within a minefield, it runs the normal chances for hitting a mine. Ion storms have no influence on the fuel drain functions of web mines.

Conclusion

Minefields can be difficult to use effectively. However, by understanding the nine basic attributes, the probability of hitting a mine, the minefield limit, and the behavior of minefields in ion storms, a player can begin to fully exploit all of the capabilities minefields provide. In the next article I will discuss the major host phases that apply to minefields and how to lay overlapping minefields.