Ion vacuum drive

The Ion Vacuum Drive is the most common type of starship engine throughout the Known Worlds. It is used on every class and scale of ship, from fighters to capital ships, and is widely regarded as the single most versitile engine ever devised.

Development

There is no recorded date for the invention of the Ion-Vacuum drive. Very likely, numerous civilizations developed the technology independantly of one another. Earliest recorded use dates back to the Mage Wars though it may have been used in [{Antiquity]].

By the Golden Age it was the standard in starship engine. There are many different designs of Ion-vacuum drives, making the technology as diverse as the internal combustion engine. However, all operate around the same basic principles.

Operating Principle

The Ion-Vacuum drive employs a ramscoop to suck in fuel from the fabric of space. Anything will do; trace gasses, dust, whatever is in front of the ship gets sucked into the engine and combined with "dry" plasma where it burns intensely. The plasma is then ionized in the primary drive chamber, adding energy to it and causing further expansion as it is expelled out the back of the ship, causing forward motion.

Dry Plasma

Dry Plasma is pure, highly-energetic plasma formed by a matter/anti-matter reaction. This plasma is generally used as a 'spark' to burn materials gathered by the ramscoop, forming "drive" plasma.

Drive Plasma

Drive Plasma is the plasma actually used to propell the ship before ionization. Drive Plasma is produced when fuel is mixed with dry plasma and burned. In a traditional ion-vacuum design, the fuel source is material gathered by the ramscoop, however literally anything can be used for fuel.

Fuel

Technology similar to that of Bussard collectors are used in the ramscoops. The traditional fuel for an ion-vacuum drive is whatever is gathered from these collectors. In larger ships, waist from the vessel is often burned for fuel. Duetrium is also a popular fuel source as it is plentiful and highly effective. Once a fusion reaction is sparked in the duetrium, the matter/anti-matter reactor is no longer required. Most large ships will use a system like this as duetrium is highly plentiful and easy to store while anti-matter refinement and storage is not.

Power Requirments

The Ion Vacuum drive is curious in the high variability of it's power requirments, specifically it's lectric-to-fuel ratio. More available fuel = less electricity. Less fuel = more electricity. It's effeciency then varies according to fuel availability, with higher available fuel allowing for greater speeds while retaining greater economy. However, the equation is often more complicated than that.

Aside from energy used in plasma manufacture and containment, the engine requires electrical energy to ionize the plasma in the pre-fire chamber. When more fuel is available, less electricity is typically required, to a point. More fuel being burned results in less energetic plasma, which produces less thrust. At lower speeds, such as the cruising velocites of large ships, this is not an issue, as even with a very high fuel/dry plasma mix, 30-40 PSL can still be reached with little ionization.

However, smaller craft, such as fighters, run into a great deal of difficulty. They lack the power generators needed to produce highly ionized plasma. For thousands of years, the Bussard Ramjet was the preffered solution, as it required relatively low power and no fuel. However, it was slow at changing velocities and useless for manuevering.

In the late Fifth Age, the technique of "sweetening the mix" allowed the Ion-vacuum drive to dominate as a main engine. This simply involved burning more antimatter fuel to achieve higher velocites, thus resulting in a higher dry plasma/fuel ratio. It significantly decreased fighter range, but allowed for 70PSL+fighters to become a reality.

Self-Powering Varient

A self-powering variation of the Ion Vacuum drive was developed for the Harpy-class of long-range bomber built by the Gudersnipe Foundation. The design simply used the mechanical motion of the expanding dry and drive plasma passing through the engine to produce electrical energy to power, which is then used both to ionize the plasma and to power the ship. The problem with this variant is that it requires drastically more anti-matter. However, in the Harpy, it allows the ship to effectively not have an internal power generator.