5 Propulsion Systems
5.1 Warp Propulsion System
Designed specifically for the Intimidator Refit-class starship, the General Electric Class 251-H M/ARA drive and power system was a first for Starfleet. Compared to other starships of similar size and mass, the Class 251-IR would at first appear to be quite over-powered for the Intimidator Refit, but this is not so. Even with the secondary core operating at full capacity the Primary Core of the Intimidator Refit class must produce twice the power output of the Class 8 design employed aboard the Sovereign class to maintain normal operations. In order to successfully bring the quantum slip stream drive online the core must be triple standard operational output.
A breakthrough design came about with the advent of the Class 7 warp reactor during the Defiant Class Project, which makes use of four-lobed magnetic constriction segment columns that allow for additional reactant streams to surround the primary stream that travels down the center of the magnetic constrictor columns. The 251-IR improves on this design using a system of compact magnetic isolation bearings to further concentrate the flows into the center reaction chamber, resulting in a near 600% increase in yield over previous reactors which relied on the a more basic lobed design. The 251-IR has 8 lobes each carries 2 streams in addition to the central feed stream allowing for 17 streams to be generated.
Another large advancement utilized in the development of the warp propulsion system was the utilization of a rotatable di-lithium articulation chamber within the warp core, where the matter and antimatter reactants are combined to create the high-energy warp plasma needed to power the engine nacelles, as well as shipboard systems through the use of EPS power taps. Computer-controlled rotation of the frame allows for manipulation of the manner in which the reactants meet, allowing for further control of the warp plasma into a "cleaner" power source. Redesigned verterium cortenide components within each pair of warp field coils is then able to use the warp plasma to generate a more energy-efficient subspace field with less particle waste products and stresses that were found in older propulsion systems to damage subspace. After the fleet-wide installation of this new variable warp geometry system, Starfleet was able to remove the so-called "Warp Speed Limit" of Warp 5, established in 2370 after the discovery of pollution by Dr. Serova in the Hekaras Corridor. Pursuant to Starfleet Command Directive 12856.A, all starships traveling within Federation space are required to receive engine upgrades that prevent the further pollution of subspace by 2380.
Unlike in previous reactors the Plasma generated by the super efficient 251-IR contains too much power to be directed through conventional plasma conduits. Instead specially designed conduits carry the raw plasma stream to a secondary unit which steps the plasma down which is then fed into plasma conduits and the EPS network.
The Secondary Core is a modified Class 7 Core. The secondary cores primary purpose is to provide additional power for mission elements however if necessary it can be modified to provide power for warp travel.
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5.2 Impulse Propulsion System
The basics of Impulse Engine design as employed by the United Federation of Planets, and most other major powers, have remained more or less static for almost a century now. In general, Impulse engines consist of four main components:
The fuel tank contains the reactants used within the engine. Starfleet uses simple Deuterium fuel1 - less efficient than a Deuterium/Tritium mix, but Deuterium is far easier to produce and handle than Tritium, while using only one type of fuel eliminates the necessity for two independent sets of fuel storage and handling systems within the ship.
Once the fuel has left the tanks, it is reduced in temperature to form pellets of solid Deuterium ice of variable diameter. These are fired into the reactor where a set of fusion initiators are used to ignite the pellet whilst a magnetic field holds them in place. The Deuterium atoms are fused together in part according to the equation:
Which gives the conversion of mass to energy a theoretical maximum efficiency of 0.08533% - in practice other reactions and engine design produces different efficiencies. The standard Impulse fusion reactor as used in the Galaxy class Starship is a sphere six meters in diameter, constructed of dispersion-strengthened hafnium excelinide. The reactors can be networked together, with each one passing its plasma output to another in a cascade fashion. Each of the eight Impulse engines on a Galaxy class starship has three fusion reactors connected together in this manner.
Once the Deuterium has fused successfully, the plasma stream created is passed through the next major component - the space-time driver coil. Under the Einsteinian physics which holds true for objects at sub-warp velocities it is virtually impossible for a simple fusion rocket to deliver sufficient energy to accelerate a spacecraft to near light speed - the fuel requirements rapidly increase to the point where the large majority of the vessel would be dedicated to fuel tankage. The coil avoids this situation by generating a sub-warp Cochrane field around the vessel, reducing its effective mass in order to boost the acceleration.
Actual Impulse flight performance is therefore dependant not only on the specifications of the fusion reactors, but also on the capabilities of the driver coils. One of the fastest ships ever fielded in terms of Impulse performance was the refit Constitution class. This ship was capable of reaching 'Full Impulse' (25% c) in a matter of seconds. At the other end of the scale the much later Ambassador class was designed to achieve a far more lowly acceleration of 10,000 ms-2, sufficient to reach Full Impulse in 125 minutes.
Once the plasma stream has passed through the driver coil assembly, it reaches the exhaust port and passes into space. If the coil itself is not engaged, the Impulse Engine reverts to behaving like a simple Newtonian fusion rocket with a performance thousands of times less than its normal capabilities. Under these circumstances the exhaust system is designed to vector the thrust of the engine in order to correct for unusual mass distributions or provide off-axis thrust for enhanced agility.
At velocities which are an appreciable fraction of that of light, time dilation becomes a factor for Starship crews. When a ship travels very near to the velocity of light, this effect can become very significant. For example, at the 92% c which is the maximum velocity of the Galaxy class Starship over 2.5 days would pass for a stationary observer for each day which passed for the crew. In order to keep these effects below a 3.5% time differential, the Federation has long imposed a ban on Impulse flight above velocities of 0.25 c - so called "Full Impulse" - on all normal missions. While this restriction is not applicable during combat operations, the effects of time dilation can have extremely adverse effects on a vessel in these conditions - a crew can find themselves in a position where their reaction time will be greatly reduced compared to an enemy because of the difference in velocities between them. High relativistic speeds are therefore generally avoided altogether by Starships.
Early space vessels had to mount so called "retro-rockets" in order to slow themselves down as they approached their destination, or else turn their craft backwards and use the main engines to slow down. One further advantage of utilizing the driver coil in an Impulse engine is that this rather cumbersome requirement is removed. The driver coil essentially allows the ship to reduce its mass in order to allow a - relatively - small amount of kinetic energy to create a great deal of velocity. Once the coil is discharged, the ship returns rapidly to its normal mass. The kinetic energy remains constant, so the velocity is vastly reduced without any need to use the engines thrust.
In theory, the coil alone could be used to drive the ship by simply adjusting the mass so that the velocity reaches the desired level. In practice, however, it is not that simple. The coil cannot be simply turned up and down as required, but is rather discharged and then recharged by the flow of plasma through it - essentially, by the normal operation of the impulse engine. It is thus not possible to 'tune' a ships mass up and down as required. Overcoming this limitation has been the holy grail of Impulse engine designers for well over a century, but as yet no progress has been made.
The Intimidator refit employs two modified High output Sovereign Class Impulse engines providing thrust far in excess of the highest estimated needs. So great is the thrust provided by each individual engine that the Intimidator Refit Class has 0% loss of performance with the loss or destruction of one of her Impulse engines. Like other ships before her, Intimidator Refit class vessels utilizes space-time driver coils within its impulse engines to create a non-propulsive symmetrical subspace field that effectively lowers the ship's mass, making it capable of pushing the entire spacecraft using less fuel. There are two impulse engines on the ship, each operating at 25% rating for standard operations, but can boost their output to 50% for combat operations.
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5.3 Quantum Slip Stream Drive System
The Federationís first encounter with Quantum slip stream drive technology came under less than ideal circumstances. In 2374 the USS Voyager encountered a fake federation star ship in the middle of the delta quadrant equipped with a drive technology that far exceeded the capacity of any other federation vessel to date. While this vessel was a hoax it introduced the crew to a new drive technology which greatly intrigued federation scientists upon their return to earth.
The first Federation Vessel to built with a dedicated quantum slip stream drive system was the USS Nimitz, a test ship designed to be identical to the vessel discovered in the Delta quadrant. The Nimitz successfully obtained slip stream speeds for nearly 2 minutes before it fell back into normal space.
The Federation then worked on designing a vessel with a conventional warp core which would power a second generator to obtain slip stream speeds. The USS Excalibur was re-launched after heavy refit with the first federation quantum slip stream generator which could maintain a stable slip stream portal. Since then tremendous advancements have been made in the field of Slip Stream drive technology, however the point has not yet been reached where a quantum slip stream drive generator can be constructed to maintain a portal for more than a matter of minutes.
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5.3.1 Mark V Spatial Dilation Generator
The Intimidator Refit is equipped with a Mark V Spatial Dilation generator which represents the most recent drive system produced by Starfleet. Unlike previous dilation generators which could only operate for brief hops at slip stream speeds the Mark V is capable us sustaining near indefinite Slip stream speeds by using the Intimidator refit classís advanced deflector system to compensate for the stresses encountered even in limited quantum slip stream travel. The Mark V is comparable to the over powered Mark II Spatial dilation generator employed by the massive command carrier class vessels.
Much like previous generators the Mark V creates a tremendous power draw, drawing nearly two thirds of the total output from the primary core, to create a slip stream conduit, however once the conduit has been stable the energy required to maintain it decreases exponentially. The key advancement of the Mark V is the interface between the generator, computer and deflector system which allows ships to maintain slip stream speeds for near indefinite durations, limited only by their fuel reserves.
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5.3.2 Slip Stream Support Systems
The Intimidator Refit class employs a number of secondary systems to assist in the use of its quantum slip stream drive system. Even slight navigational errors while at slip stream speeds can result in an impact with planetary bodies. As such the Intimidator refit employs a system of redundant NAV COM arrays to insure that all navigational calculations are within acceptable tolerances, usually less than 1/10,000 of a percent.
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5.4 Reaction Control System
The RCS system is employed aboard all federation starships. The RCS is a low-power propulsion system for low-velocity attitude and translational control. Depending on the starship type, the system consists of a number of thrusters mostly located at the edge of the saucer hull. Although the Intimidator Classís RCS is based on a fusion reaction, its principle has not changed since the early days of space travel in the 1960s, and similar thrusters were attached e.g. to the hull of the Apollo spaceship.
The Reaction Control System thrusters are adapted from thruster packages from the successful Galaxy-class vessel. A total of forty thruster groups are installed; ten on the primary hull, five on the secondary hull and five at the aft of each nacelle. The Deuterium is supplied to each thruster by the central deuterium tanks, as well as immediate-use tanks within thruster packages. Each thruster quad can produce 4.5 million Newtons of exhaust.
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