Ion Engines of the Frontier

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by Edwin Cintron

How we computed the cost of fuel load

An Ion engine use 1 fuel unit per ADF, An ADF is basically 1 G of acceleration over a 10 minute period (Knight Hawks combat turn.) To accelerate to 1% speed of light would take 508.5 ADF and additional 508.5 ADF to decelerate.  At 10 Cr. per fuel that comes to 10170 Cr per jump.

While Atomic Engines are the stars of travel on the Frontier, Ion engines are the overlooked workhorse. The atomic fuel pellet expended on a single jump represents a major expense for most cargo ship at cost of 10,000 Credit per engine, while the same trip would use 1017 units of fuel per engine at a cost of 10170 credits. Add to this the cost of over haul and the initial purchase costs, Ion rockets not only make sense for in system ships but can be a cheap alternative to standard Atomic drive.

Generally overlooked in the Knight Hawk construction rules is ship power. While Atomic drives can be tapped as a power source, Ion engines will need to draw on an external source of power in order to operate. Generally all space craft are equipped with a bank of parabatteries to provide backup power. Standard ion engine will require at least 1000 SEU of power to make a change of 1 ADF.  See chart to see energy cost per engine type:

Power requirement per Engine type




1,000 / ADF


2,000 /ADF


3,000 / ADF

Generally a generator will also be required to recharge the parabattery banks and provide ship power. Typical these generators require a power source, while solar arrays can be used by system ships, 5 square meters of solar panel is needed for each SEU/HR the generator can produce. Solar panels cost 10 Credits per 5 square meters, and are destroy on any weapon hit. (Optionally you can rule the number of m2 destroyed is equal to damage the weapon inflicts)

Atomic piles can also power these generators, a typical portal self-contained fission pile is 3m in diameter by 15m long and can provide 200 SEU/s and has a life span of 30 years. Cost of one of these piles is 1 million credits. The reactor requires a 4 function point computer program.  Typically only 1 such reactor is needed for most ion drive starships but if the craft is heavily armed, a second reactor is needed to run any energy weapons the ship processes. A typical laser battery requires 20 SEU per shot, and electron or proton particle beams 100 SEU. Spinal weapons and laser cannon will consume 1000 SEU per shot. Typically these units will have their own banks of parabatteries to draw power from, but are quickly depleted without a secondary reactor to recharge them.

As a rule of thumb, we can assume that all Star Frontier ships will have installed parabatteries to handle ships function. In the case of Atomic Drives these batteries will be recharged whenever the drives are in use.

Standard number of installed parabatteries per ship size

Ship size


1 to 4

5 to 20 type 4

5 to 14

25 to 40 type 4

15 to 20

45 to 100 type 4

Generally this is enough to provide 24 hours of power to life support and ship equipment, use of weapons will quickly drain these batteries if atomic engines are off or if no portable pile is available.

Pirate Stealth craft

Cunning pirates have taken advantage of the ion drive's invisibility to energy detectors (which actually detects the radioactive and heated exhaust of Atomic drives) to ambush lightly or unarmed merchant craft. Coated with radar absorbing paint, the craft uses its ion drives to get within visible range, where it uses additional atomic drives for a sudden burst of acceleration to get within boarding range before the ship can escape.

Pirate Stealth craft

Hull size: 4

Types of engines: 2 ions, 2 atomic

ADF: 1 / 4  MR: 4  DCR: 32

Hull Points: 20

Weapons: laser battery

Defenses: Radar absorbing material

Sensors: energy detector, radar.

Note: when in stealth mode, radar is set to passive and uses target radar transmission to home in on target.