Missile EnginesIn the new version of Aurora, you will design individual missile engines rather than just allocating a set amount of space to the engine during missile design. You can allocate more than one engine of the same type to a missile design. I'll cover the update to missile design separately though as this post is purely about designing missile engines. It is worth mentioning here though that there will no longer be missiles and drones. Both will be covered by a single design process and the new engines will allow missiles with similar performance to drones.
The four elements of missile engine design are described below.
Engine Technology: Exactly as ship-based engines. For example, the Magneto-plasma Drive has a rating of 16 power per hull space, so a Magneto-plasma missile engine of 1 Missile Size Point (MSP), which is 1/20th of a hull space, would provide 16/20 = 0.8 power.
Fuel Consumption: The base fuel consumption of a missile engine is five litres per Engine Power Hour (which is one point of engine power for one hour) and can be improved through research. So a max size missile engine (5 MSP) with 4 power and a racial fuel consumption technology of 0.6 litres per engine power hour would use 12 litres per hour. This is higher than shipboard engines as missile engines are designed for single use and therefore long-term fuel efficiency is a low priority in their design. They are also solid-fuelled for easy storage, which is less fuel efficient than liquid-fuelled ship-based engines.
Engine Size: Missile engines can range in size from 0.1 MSP to 5 MSP in 0.1 MSP increments. It is hard to create very small fuel efficient engines, so smaller missile engines suffer a further penalty to fuel consumption. The formula is: Fuel Modifier = Int ((Engine Size in MSP / 5) ^ (-0.683)). There is no need to remember this formula as the % change to fuel consumption is shown for each size option in missile engine design. For example, the following sizes of missile engine have the listed fuel consumption penalties
5 MSP x1.00
4 MSP x1.16
3 MSP x1.42
2 MSP x1.87
1 MSP x3.00
0.5 MSP x4.82
0.3 MSP x6.83
0.1 MSP x14.47
Power / Efficiency Modifiers: Missile engines use the same principle as ship engines and use the same tech lines (Max Engine Power Modifier and Min Engine Power Modifier). However, the upper end of the range is doubled for missile engines. So if the Max Engine Power tech is x1.75, missile engines can use up to x3.50. The rationale is that these are designed for single use, unmanned craft and therefore have significantly different engineering requirements, such as no radiation shielding or maintenance access requirements. As with ship-based engines, increasing power has a significant effect on fuel efficiency and decreasing power can provide huge savings in fuel efficiency. As the missile modifier is double that of ships, power can be increased by up to six times normal and decreased to 10% of normal if you have the prerequisite techs. The dropdown on the missile engine design window has options from the minimum possible to the maximum possible in 0.05 increments. So 0.40, 0.45, 0.50, 0.55 ...... 1.80, 1.85, etc. Each engine power modifier percentage is accompanied by a fuel consumption modifier, based on the formula Fuel Efficiency Modifier = Engine Power Modifier ^ 2.5
For example, a 1 MSP missile engine with a x3.00 engine power modifier would have a x15.59 fuel consumption modifier for the engine power modifier and a x3.00 fuel consumption modifier (x3) for the size of the engine, which is a total fuel consumption modifier of x46.77.
A 0.5 MSP missile engine with a x5.00 engine power modifier would have a x55.90 fuel consumption modifier for the power modifier and a x4.82 fuel consumption modifier for the engine size.
Here are the three examples of 1 MSP magneto-plasma drive missile engines, using x1 power, x3 power and x6 power, with a racial base fuel consumption of 0.6 Litres per Engine Power Hour
0.8 EP Magneto-plasma DriveEngine Power: 0.8 Fuel Use Per Hour: 7.2 Litres
Fuel Consumption per Engine Power Hour: 9.006 Litres
Engine Size: 1 MSP Cost: 0.2
Thermal Signature: 0.8
Materials Required: 0.25x Tritanium 0.2x Gallicite
Development Cost for Project: 40RP
2.4 EP Magneto-plasma DriveEngine Power: 2.4 Fuel Use Per Hour: 336.92 Litres
Fuel Consumption per Engine Power Hour: 140.385 Litres
Engine Size: 1 MSP Cost: 0.6
Thermal Signature: 2.4
Materials Required: 0.25x Tritanium 0.6x Gallicite
Development Cost for Project: 120RP
4.8 EP Magneto-plasma DriveEngine Power: 4.8 Fuel Use Per Hour: 3811.86 Litres
Fuel Consumption per Engine Power Hour: 794.137 Litres
Engine Size: 1 MSP Cost: 1.2
Thermal Signature: 4.8
Materials Required: 0.25x Tritanium 1.2x Gallicite
Development Cost for Project: 240RP
As you can see, you will able to create missiles with more power than you can at the moment but also missiles with far more endurance. Just not both at the same time
. Missiles with a range of several billion kilometers will be possible. The problem will become targeting the enemy rather than designing a missile with the necessary endurance.
Edited 22-Apr to remove the x2 power modifierEdited 31-Jul to add the fuel consumption penalty for sizeEdited 23-Sept to change to a new fuel consumption formula for power modifiersSteve