LegacyWorlds Beta 6

In the previous post about travel and distances, we discussed the generalities about travel in the Legacy Worlds universe. This new post in the series describes the structure of stellar systems and the travel rules that apply.

Stellar systems have two “levels” of structure. First there is a general structure, common to all stellar systems; this level includes the Oort cloud and the locations of the various “orbits”. The second level is specific to what can be found at a given orbit: life-supporting planet, planetary remains, gas giant, asteroid belt or, well, nothingness.

General structure of stellar systems

As stated in the introduction, all stellar systems, regardless of their actual contents, share a similar structure. The graph below describes this structure:

The blue areas on the graph are empty zones; while it is impossible for a ship to stop in one of these areas, they must still be traveled through when navigating inside the stellar system. When coming from outer space, the first area that ships will enter is called the outskirts; while it is still outer space, it is considered a part of the system as only ships going somewhere inside the systems would enter it. The next area is the Oort cloud, which has a specific sub-structure, and some more empty space. After that, there are 5 areas called “orbit regions”, which contain two layers of empty space surrounding an area which may contain an object such as a planet or asteroid belt (the exception being the innermost orbit region, which only contains one area of empty space, since having an empty area in a direction in which you can’t travel anyway wouldn’t make much sense).

In terms of distances, the Oort cloud as well as empty areas have a “width” of 50 distance units, while an orbit has a total “width” of 20 units. Because of the stellar system’s gravity well, a Hyperspace multiplier applies for all in-system travel; this multiplier ranges from 10 on the outskirts to 145 in the innermost orbit.

The Oort cloud

A system’s Oort cloud is divided into 3 different areas. All of these areas are filled with various debris, albeit in different proportions. Of course, the cloud’s core - the middle area - is both wider and harder to navigate than the two others. Each Oort cloud has a specific density.

The density of the debris is low enough not to cause any additional perturbations on Hyperspace travel. However, normal space multipliers are applied: in the outer areas, this multiplier can be as high as 2, and it can reach 4 in the cloud’s core (the actual value of the multiplier depends on the cloud’s density).

Planetary bodies

Planetary bodies (life-supporting planets, gas giants and planetary remains) share a similar, relatively complex structure. The complexity of this structure is required for the game to handle ships being redirected in the vicinity of a planet. The graph below shows the various areas around a planetary body.

The A, B, A’ and B’ area are used to compute trajectories for ships passing by a planet. A and A’ are “approach vectors” - anything that has to go to the planet or just move by it will fly through these areas. B and B’ are only used for ships passing by. However, if the orbit being considered is the closest to the sun, only A is available as any ship going there is obviously headed for the planetary body’s orbit.

The O1, O2 and O3 regions are positions in orbit around the planetary body; ships can stay at these locations. However, the O2 and O3 areas are only available on actual planets; planetary remains and gas giants only have an O1 area.

Because it is possible for a fleet to change trajectory, it is possible to go from any of the A, B, A’ or B’ areas to the orbital area. Such transitions are only possible between areas. In addition, the “width” of these areas have been computed so that the path to O1 that passes through B or B’ is always longer than the direct path.

Depending on the type of planetary body, different modifiers apply; actual planets and planetary remains will not affect travel in normal space, and gas giants will actually give a 300% speed boost. In the case of Hyperspace travel, the planetary body’s gravity well will cause additional trouble, depending on the size of the planet.

Asteroid belts

The structure of asteroid belts is very similar to the one used for Oort clouds. An asteroid belt is composed of three areas: two outer areas of lower density, and the belt’s core, a smaller area with a much higher density (this area is where minerals are mined from).

The density of asteroid belts is too low to have an effect on Hyperspace travel. It does however impact normal space travel greatly, as the multiplier grows exponentially depending on the belt’s density.

Next time, on the LWB6 blog…

We’re going to talk about the structure of space near nebulae and supergates, which is both as important and as boring as this was…