Propulsion

Five types of spaceship drives (also called engine for propulsion) are available: chemical fuel engines, ion engines, HEPRE, atomic engines and Pion Engines. Each of these types has certain limitations and requirements which are discussed in detail here.

In addition to a drive, each ship must have a drive program for the on-board computer. Information on Drive Programs is included at the end of this section.

Sizes. Engines of all three types come in three

sizes, ranked from size A to size C. Size A is the smallest, and size C the largest. A hull must be equipped with the engine size appropriate for that hull size, as shown on the Hull Size/Engine Size Chart.

SPACESHIP DRIVE SIZE CHART

All engines are equipped with maneuver jet nozzles. These are used to take the ship through delicate maneuvers, such as docking with a station.

Chemical Drives

Chemical drives are the cheapest and simplest spaceship engines.  They come in two types; solid and liquid fuel.  Chemically driven ships must carry a lot of fuel, and cannot accelerate long enough to achieve interstellar speeds. Therefore, there main use is for interplanetary travel.

Any hull that is outfitted with chemical engines must have the full complement of engines for that hull. For example, a ship with a hull size of 13 needs four chemical engines. These engines are mounted at the tail of the ship, instead of away from the ship on struts.

All ships with chemical engines have an ADF of 1.

The Chemical Drive Price Table lists the prices of the three types of chemical engines. Because these engines are simple and easy to build, the cost is the same at all construction centers.

CHEMICAL DRIVE COST CHART

Solid Fuel rockets are the most common type of rockets.  They are used in fireworks, munitions and booster rockets for the space shuttle.   Solid fuel rockets burn a solid propellant to create thrust.  Once they are ignited they can't be stopped and there rapid burn rate depletes the fuel quite rapidly.  This rapid usage of fuel gives an aircraft or spacecraft an extra 'burst of speed" when taking off .  They can also be used to aid a rocket with a large payload achieve orbit.

On spacecraft solid fuel rockets are used as booster rockets that enable spacecraft to achieve orbit.  Booster Rockets are rented.  They are mounted to the hull by special equipment or permanent fixtures bought at time of spacecraft construction.  Once the propellant has been used up during launch, the rocket is ejected, after a delay meant for the spacecraft to clear the area a parachute opens and the rental company recover it.  The number of Booster Rockets needed is the same as the full complements of engines for that hull.  The cost to rent one these is 250 Cr x the hull size of the ship for each Booster Rocket.

Liquid Fuel Rockets fuel of choice is Liquid Hydrogen and Oxygen (HyLox for short).  The hydrogen and oxygen are stored in two different tanks, with the hydrogen being the largest of the two.  The fuel is mixed and ignited in the engine to create thrust.  The engine can be switched off and on as needed.  Ships using chemical drives burn a load of fuel on every voyage, as a general rule. The cost of one load of fuel is 250 Cr x the hull size of the ship for each engine.

Ships design for planetary reentry, such as shuttles and landing craft, must carry twice as much fuel for landing and takeoff.  Ships designed for long range exploration must carry 1/3 or 33% of the fuel if they are expected to make the return trip.  Extra fuel tanks can be mounted  on the hull with specialized equipment or with permanent fixtures bought at time of the ship's construction.  Additional fuel tanks cost 100 Cr per hull size.

Ion Drives

Ion engines work by ionizing (electrically charging) particles of fuel. These charged particles are then released from the rear of the engines at tremendous velocity. Even though the particles are extremely small, there are enough of them to provide a ship with a steady and long-lasting thrust. Ion drive engines require very little fuel.

Ion engines must be mounted on struts, away from the hull of the spaceship. Any ship equipped with ion drives must have the full complement of engines for that hull size in order to accelerate and decelerate normally. The ADF of a ship with ion drive always is 1.

Prices for ion engines are listed on the Ion Drive  Price Table. Note that ion engines are not available at Class III Construction Centers, and that they are more expensive at Class II Centers.

Ion Drive Cost Chart

The drive uses liquid hydrogen as a propellant. The engine can be switched off and on as needed.  Since they use so little fuel  they can make multiple trips on a single load of fuel. Ships using Ion drives burn a load of fuel depending on their Engine Size. The cost of one load of fuel is 100 Cr x the hull size of the ship for each engine.

Fuel Usage for Ion Drives

Ships that are intended for combat missions burn one load of fuel during combat, as a general rule.

High Efficiency Plasma Rocket Engine

High Efficiency Plasma Rocket Engine (HEPRE for short) is a rocket engine that uses the heat of an atomic power plant to heat liquid hydrogen to a plasma state, contain it in a magnetic bottle then release it to create thrust.  The reactor's shielding prevents radiation from escaping from the power plant making the exhaust of the HEPRE free of radiation associated with atomic engines.  Since the power plant of the HEPRE runs hotter than normal atomic engines, there is heat risk associated with these engines and they must cool down before being approached by the crew.

The struts that house the HEPRE are mounted on are equipped with explosive charges. These charges enable the pilot or engineer to jettison the engines if this should become necessary. This obviously will be done only in extreme emergencies, such as an engine meltdown or overload.

Ships equipped with a full complement of HEPRE both its ADF and MR will be the number indicated on the Hull Specification Chart.  For each engine less than the maximum, however, either the ship's ADF or MR (player's choice, at time of construction) must be lowered by 1. The ship's MR cannot be more than one higher than the ADF. Also, the ship's ADF and MR never will be less than 1, even if the ship has only one engine.

Prices for HEPRE are listed on the HEPRE Drive  Price Table. Note that HEPRE are not available at Class III Construction Centers, and that they are more expensive at Class II Centers.

HEPRE Drive Cost Chart

The drive uses liquid hydrogen as a propellant.  The fuel can be turn off and on as needed, however will remain extremely hot for 1d10 hours before it reaches an idle state. The cost of one load of fuel is 100 Cr x the hull size of the ship for each engine.

Fuel Usage for HEPRE Drives

Ships that are intended for combat missions burn one load of fuel during combat, as a general rule.

Atomic Fuel

HEPRE reactors use atomic reactors to produce the heat necessary to turn the hydrogen  into plasma and to power the ship.  Because the reactor is run at high temperatures fuel rods are depleted at a much quicker rate than normal ground based reactors. Therefore it is necessary to replace these rod once every year at a cost 50,000 Cr per engine size times the number of engines.   These rods are replaced at special facilities at Class I or Class II Construction Centers.

Inspections

The reactor shielding must be inspected each trip for damage caused by the extremely cold liquid hydrogen coming in contact with the shielding and warping do to the extreme heat caused during plasma generation.  All shielding is replaced during the refueling process.

As already stated there is 1d10 cool down time for the reactor before anyone can approach it.  Engineer must use anti-radiation suits or work pods during the inspection process. To determine how long this inspection takes roll another 1d10 and subtract the engineers skill level from that roll.

During normal operation cycle of the engine there is a 10% chance that there is some damage to the shielding.  If defective or damaged shielding is found it must be replaced (see atomic engine overhauling). If an inspection is not made after each trip the risk of damage increase by 10% every trip missed.

Atomic Drives

The engine works by harnessing uranium particles that are boiled off the reactor mass during the reactor's operation cycle.  These fission fragments are then channeled out the exhaust nozzle by an electromagnetic field.  This  provides a tremendous amount of thrust. An  Atomic engine will burn 10 cm diameter chunks of fuel during the thrusting stage of interstellar jumps.

Atomic engines are mounted on struts that keep them away from the ship's hull. This is because these drives are a source of dangerous radioactivity, and must be isolated from the crew and living quarters of a ship.

Ships equipped with a full complement of atomic engines both its ADF and MR will be the number indicated on the Hull Specification Chart.  For each engine less than the maximum, however, either the ship's ADF or MR (player's choice, at time of construction) must be lowered by 1. The ship's MR cannot be more than one higher than the ADF. Also, the ship's ADF and MR never will be less than 1, even if the ship has only one engine.

Prices for Atomic Engines are listed on the Atomic  Drive  Price Table. Note that Atomic Drive are not available at Class III Construction Centers, and that they are more expensive at Class II Centers.

Atomic Drive Cost Chart

In addition to the initial cost, atomic engines are more expensive to maintain than other types of engines.

Atomic Fuel

A pellet of atomic fuel is a 10 cm diameter piece of radioactive material, either plutonium or uranium.  One pellet costs 10,000 Cr. They can be purchased only at Class I and Class II Construction Centers.

A pellet will provides just enough fuel to permit a ship to reach the velocity required for an interstellar jump, or one month of normal operation. Once the pellet has expended all the fission fragments  the pellet is considered to be burned out and must be replaced.  Burned out pellets will still provide 1d10 x 10 hours of power to the ship after it has reached this stage.  Depleted pellets are sold back to the Construction Center for 1,000 Cr and are recycled.

An atomic engine can automatically replace the fuel pellet before this stage, if the engine has been preloaded with additional pellets. Depending on the engine size, this can be anywhere from 3 to 10 pellets. Additional pellets can be stored on board in specialized containers housed in the engineering section.  Only a trained Spaceship Engineer can load the engine.  Refueling takes 2d10 hours minus the engineer's skill level.  It requires the engineer suiting up in an anti-radiation suit or work pod.. Most of the time is spent removing access panels and shielding, the time is the same no matter how many pellets are being loaded.

Overhauling Engines

Besides refueling, these engines must be overhauled regularly by an engineer. To determine how much time is required for the overhaul, use the following formula.  60 hours minus 1d10 times skill level. If a the ship doesn't make a jump within a month the engine must be overhauled prior to making the jump.

The Atomic Drive  Information Table lists the number of trips each type of atomic engines can make between interstellar trips.

If the ship is equipped with more than one atomic engines each must be worked on separately.

If an atomic engine is not overhauled on schedule and the ship tries to make an interstellar jump, there is a 60% chance that the engine will fuse itself into a worthless lump of iron.  If a second jump is made the risk increases to 80%.  An attempt at third jump cannot be made and will automatically ruin the engine.

If there is an engineer on board, he has a chance to realize that the engines are about to become fused. This chance is equal to his Logic score plus 10% x his engineering skill level. A successful roll means the engineer can shut down the engines before they are ruined. However, no further acceleration will be possible until the engines are overhauled.

Atomic Drive Information Chart

Pion Engine

A Pion Engine uses liquid hydrogen fuel, subjected to X-ray bombardment in the bombardment chamber, the resulting liquid anti-hydrogen fuel being siphoned off and injected into the primary reaction chamber along with the remaining liquid hydrogen fuel, the resulting explosion energizing thermopiles lining the chamber, with the pions generated from the matter/antimatter reaction directed through the exhaust chamber by magnetic coils which compress the pion stream to generate a higher specific impulse than would be possible with other engine designs.

Pion Engines are mounted on struts that keep them away from the ship's hull. This is due to the matter/antimatter reaction and fear of explosion if damaged.

Ships with pion engines have an ADF one point higher than ships equipped with atomic engines. They are also smaller than atomic engines which means any two atomic engines can be replaced by a one size larger Pion Engine.

Prices for Pion Engines are listed on the Pion  Drive Price Table. Note that Pion Drive are not available at Class III Construction Centers, and that they are more expensive at Class II Centers.

Pion Drive Cost Chart.

The drive uses liquid hydrogen as a propellant.  The fuel can be turn off and on as needed.  The cost of one load of fuel is 100 Cr x the hull size of the ship for each engine.

Fuel Usage for Pion Drives

Ships that are intended for combat missions burn one load of fuel during combat, as a general rule.

Pion Engines are overhauled once six months at a cost of 100,000 Cr per engine size times number of engines. These can only be done at Class I or Class II Construction Centers.

Inspections

After each trip the engine must be inspected to insure the safe operation of the bombardment chamber, antimatter storage container and exhaust chamber.  To determine how long these inspection takes roll a 1d10 and subtract the engineers skill level from that roll.  No safety equipment is require to do these inspections.

During normal operation cycle of the engine there is a 5% chance that something will wear out.  If an inspection is not made after each trip the risk of damage increase by 20% every trip missed.