Table 5-4: Engines
| Engine | Tech | Pow | Min Size | Base Cost. | Cost/Hull | Accel @ 5% | @ 10% | @ 15% | @ 20% | @ 30% | @ 40% | @ 50% | Eff. | Cost |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Planetary thruster | - | 1.0 | 1 | $200 K | $50 K | 0.1* | 0.25* | 0.5* | 1* | - | - | - | 10 | $10 K |
| Photon sail | - | - | 5 | $500 K | $50 K | – | 0.02* | 0.05* | 0.1* | 0.15* | 0.2* | 0.25* | - | - |
| Fusion torch | - | 0.33 | 3 | $500 K | $100 K | 0.5* | 1* | 1.5* | 2* | 3* | 4* | 5* | 200 | $1 K |
| Ion engine | S | 0.5 | 2 | $800 K | $200 K | – | 0.5* | 1* | 1.5* | 2* | 3* | 4* | 400 | $5 K |
| Particle impulse | - | 0.75 | 4 | $500 K | $300 K | 0.5 | 1.0 | 1.5 | 2 | 2.5 | 3 | 4 | - | - |
| Induction engine | G | 1.0 | 2 | $1 M | $500 K | 1 | 2 | 3 | 4 | 5 | 6 | 8 | - | - |
| Inertial flux engine | X | 1.0 | 1 | $2 M | $500 K | 2 | 3 | 4 | 5 | 6 | 8 | 10 | - | - |
| Gravitic redirector | G | 0.67 | 3 | $3 M | $1 M | 2 | 4 | 6 | 8 | 10 | 12 | 16 | - | - |
| Spatial compressor | T | 2.0 | 4 | $1.5 M | $200 K | 3 | 6 | 9 | 12 | 15 | 18 | 20 | - | - |
Tech: The technology type required to build an engine of this type. Power: The number of power points required by each hull point assigned to this engine. For example, a 30-hull point fusion torch requires 10 power points to operate. Min Size: The smallest number of hull points that can be assigned to this system. Base Cost: The cost for an engine installation of this type. Cost/Hull: The cost per hull point assigned to this engine; cumulative with the base cost. Acceleration rating at…: The ship’s acceleration for an installation comprising 5-50% of its overall hull. For example, a ship of 100 hull points with 20 hull points of induction engine possesses an acceleration of 4. Eff.: The fuel efficiency of the engine. A single hull point devoted to fuel powers a 1-hull point engine for this many days of continuous operation. Cost: The cost per hull point devoted to fuel for this type of engine.
Engine System Descriptions
Not all engines are created equal. Low-tech engines may take hours, days, or weeks of continuous acceleration to build up to a speed that a high-tech engine can match in a matter of two or three phases. When you select an engine system for your starship, record the engine’s acceleration rating on your ship record sheet and assign the engines to one or more hit locations. See the later part of the chapter for more information.
Photon Sail (PL 6) This device is an immense but incredibly fragile foil structure only a few molecules thick. It uses light pressure from a nearby star or laser drive station for its motive force. Its acceleration rates drop by 50% if the ship is more than 5 AU distant from the system’s star.
The sail can be wrecked by the most minor damage, but every ship equipped with a photon sail carries at least three spares. Unfortunately, it takes hours to stow or deploy a sail.
| Crew Check | Crit. Failure | Failure | Ordinary | Good | Amazing |
|---|---|---|---|---|---|
| Deployment | d4+1 days | 3d4 hours | 2d4 hours | 1d4 hours | 1 hour |
In combat, any weapon hit destroys a deployed photon sail and prevents the sail-ship from making maneuvers until the sail can be re-deployed. The sail-ship will continue on its last course and retain its former speed until it gets a working sail again. Since ships powered exclusively by sails can’t change course easily, assume that all sail-ships are Class I maneuverability.
It’s a good idea for a sail-ship to carry a secondary propulsion system such as a small ion engine or rocket for emergency maneuvering and sailing against the sun. Photon sails are completely useless in atmosphere—in fact, they’re instantly destroyed by atmospheric entry. Most sail-ships carry a small back-up propulsion system for fine maneuvering.
Planetary Thruster (PL 6) Several PL 6 engine systems are useless or dangerous in any kind of atmosphere. The planetary thruster is a backup engine system designed specifically for use when the ship’s main drives must be shut down to make planetfall. The most common varieties are the scramjet, chemical rocket, or powered airfoil. The exact form doesn’t matter. The planetary thruster requires either fuel or power, but not both. You can choose to install a standard fuel tank, or to make sure that the ship has enough power available to run a planetary thruster at need.
Fusion Torch (PL 6) This engine is basically a fusion reactor with one wall of the magnetic bottle missing; the exhaust is incredibly hot plasma. The fusion torch is intended for space-only work; its exhaust stream would slag anything it landed on and incinerate everything within a few hundred meters of ground zero. Many ships fitted with fusion rockets carry planetary thrusters for atmospheric work, or remain permanently in space, using shuttlecraft to reach a planet’s surface. Its fuel is hydrogen, fused in the reaction chamber and expelled as white-hot plasma.
Ion Engine (PL 6) The ion engine uses power to break down molecules of a fuel material to create ions, and then expels them by means of a magnetic impeller. It doesn’t provide the thrust potential of the fusion torch, but it’s much more fuel efficient, and its exhaust is not anywhere near as dangerous. Ion engines don’t function in any kind of atmosphere, so most ships with this kind of power plant also carry a planetary thruster.
Particle Impulse Engine (PL 7) This is simply an improved version of the PL 6 ion engine. The particle impulse drive uses magnetic fields to produce a constant stream of high-energy particles and vector it for thrust. Unlike the ion engine, the particle impulse engine doesn’t require a fuel tank. Its reaction is so efficient that the very small amount of matter present in interplanetary or interstellar space can be collected through weak magnetic fields and converted into a thrust medium. The particle impulse engine is capable of atmospheric entry. It causes some damage to any surface close to its exhaust ports, but it’s not too much worse than a modernday jetwash.
Design Tip: Engines An engine of 10 to 20 percent of your hull is pretty reasonable. Anything more than that is going to be nearly impossible to design around, unless you’re building a special fast courier with minimal armament and amenities for the crew.
Induction Engine (PL 7) Hands-down the best engine available at this or any previous Progress Level, the induction engine uses artificial gravity to provide incredible thrust and maneuverability. The induction engine requires no fuel and produces no exhaust; it’s ideal for atmospheric, orbital, or deep-space work.
Inertial Flux Engine (PL 8) By precisely controlling the quantum energy level of every atom on the ship simultaneously, the inertial flux engine assumes the inertial states necessary to produce motion in any direction. In effect, the pilot chooses from instant to instant what vector the ship will next possess, and the inertial flux engine makes it possible. This engine requires no fuel and is safe for atmospheric work.
Gravitic Redirector (PL 8) A refinement of the induction engine, the gravitic redirector changes the ambient gravity in the vicinity of the ship to produce a motive force. It’s more powerful and more efficient than the induction engine.
Spatial Compressor (PL 9) One of the most advanced engines available, the spatial compressor surrounds the ship in a field that “folds” or “wrinkles” the structure of space in the direction the pilot wishes to travel. This results in a continuous series of micro-jumps in which the ship flickers into and out of reality, teleporting thousands of times every second.
Since the ship has no intrinsic velocity (it’s stationary while it teleports) the spatial compressor can instantaneously stop or change direction and thrust vector without any maneuvering whatsoever. However, the engine still needs to build up cyclic speed to increase the frequency of its microjumps, so it accelerates normally. The spatial compressor requires a lot of power, but no fuel. It’s safe for atmospheric flight.