Jump Point

Jump Points refer to any point at which a JumpShip may initiate or resolve a "jump" through interstellar space. Traditionally, there are two jump points in a system - the zenith and the nadir of a star's gravity well (normally above and below the star's planetary system ecliptic). There exist other points, called "pirate points", which a JumpShip can use; these points are more difficult to calculate, increase the chance of a Misjump occuring, and increase the likelihood of being stranded alone in the event of a misjump. However, in desperate situations or covert missions, the advantages of a speedy insertion can outweigh the inherent risks.

Because JumpShips are equipped only with weak station-keeping drives (capable of 0.1G of acceleration at most), travel between a jump point and a destination within a star system is left to other craft, primarily DropShips, which have the engines and fuel needed to make the multiday journey. The exception are combat JumpShips or WarShips which are capable of traveling under their own power.


A Kearny-Fuchida Drive must operate from some point in space where local gravity levels are below a certain minimum, allowing the K-F field to form properly. These points are generally referred to as "jump points". Finding valid jump points in both the origin and destination star systems requires calculations that take into account the positions large sources of gravitational influences, such as stars and planets.

Proximity Points

Within a star system, the biggest source of gravitational influence is the mass of star itself. For example, Sol itself accounts for over 99.8% of the mass of the entire Terran system. So almost all possible jump points are outside some minimum distance, the "proximity limit," from the system's star.[1][2][3] Jump points at the proximity limit, known as "proximity points," form a nearly uniform sphere that can range from about 75 gigameters for some red stars up to nearly 350 terameters for certain blue stars.[4]

Standard Jump Points

Calculating the location of proximity points is complicated by the motions of planets within the star system, each with their own gravitational influence. For example, proximity points in the Terran system exist near the orbital path of the gas giant Saturn, but using a proximity point near Saturn's path requires making sure that Saturn itself is not nearby.

From a computational standpoint, the easiest proximity points to determine in the Terran system are those points that Saturn never passes near. As planets tend to stay within a flattened planetary disk, the easiest proximity points to calculate are those that are "above" and "below" that disk. These points are known as the "zenith" and "nadir" points, respectively, and are collectively known as "standard jump points."

Standard jump points are where most civilian interstellar traffic takes place, and for inhabited systems installations will be constructed at the zenith and nadir points to facilitate this: transfer facilities, repair yards, and recharge stations. These two locations simplify navigation so much that they were used in the early 2100s by the Deimos Project for test jumps before mankind made interstellar jumps, and have remained the standard jump points for travel by Kearny-Fuchida drive ever since - hence, they are called the "Standard Jump Points". They are also often referred to as "zenith" and "nadir" jump points because of their locations above (zenith) and below (nadir) the star, with respect to the layout of the star system.[1][2][3]

Standard jump points are also frequently where customs inspectors and defensive units are located, and as such travelers wishing to avoid such entanglements will attempt other points instead.

Pirate Points--Non-Standard Proximity Points

The "life zone" around a star, where habitable planets tend to appear, is much closer to a star than its jump proximity limit, ranging from about 2 gigameters for red stars to up to 38 terameters for blues. [5] Difficulties and hazards notwithstanding, choosing to use a non-standard proximity point in or near a star system's planetary disk can reduce interplanetary travel times by about 5% to 10% (aassuming 1 G acceleration). [6][7]

Pirate Points--Transient Points

There are some jump points that will allow a JumpShip to enter a system inside the proximity limit. As these points are much closer to the habitable planets of a star system, they are prime choices for raiders and pirates, making them ideal "pirate points". These jump points exist where the gravitational attraction of all planetary objects cancels each other out and overall gravitation is reduced below the critical limit for hyperspace field formation.[3]

While transient point locations can be estimated by secondary school physics (generally, transient points inside the proximity limit are close to L1 Lagrange Points [8] which exists due to the cancellation of gravity between two bodies), such jump points are difficult for JumpShips to utilize because they are much smaller than the standard jump points and have much more complicated motions. Rather than only following the star like the zenith and nadir points, the pirate points are subject to gravity of other moving objects in the star system.

This makes a navigator's job nightmarish when attempting to use a transient point. Plotting the jump is impossible without computer aid, and can take hours with one. Missing the jump point is entirely possible, resulting in the JumpShip attempting to arrive in a region of space that is not a valid jump point (a fate discussed under Misjump).[1][2][3]


  1. 1.0 1.1 1.2 BattleSpace - Rulebook, pp. 42, 44
  2. 2.0 2.1 2.2 DropShips and JumpShips - Operations Manual, pp. 28–30
  3. 3.0 3.1 3.2 3.3 AeroTech 2, pp. 56–57
  4. Campaign Operations, p. 100
  5. 'Campaign Operations, p. 101
  6. DropShips and JumpShips - Operations Manual, p. 17
  7. Campaign Operations, p. 101
  8. Strategic Operations: Advanced Aerospace Rules, p. 74