Nifty Stuff for Triplanetary

Unplaytested Ideas by Stefan Jones

Includes: New Ships / Boarding Rules / Map Notes / Trade Rules

New Ships

The X-24

The X-24 is a modified corvette (2-20) with a specially streamlined hull and lifting surfaces. It can use an "aerobraking maneuver," cutting its speed by passing through a planet's atmosphere. To do the manuever, the ship's course must intersect the planet's disk. (If the ship's course intersects a planet, it MUST perform the manuever or crash.) The planet must have an atmosphere (Earth, Jupiter, Mars and Venus all qualify; so does Ganymede and Callisto after they are terraformed).

The maneuver slows the ship down by one hex per turn; if the ship is moving one hex per turn, it must land on the world. Ships attempting to land on Jupiter are destroyed.

If the ship is moving two or three hexes per turn, the maneuver adds a thrust to the ship in the direction shown by the gravity hex the ship would next enter on its current course. If the X-24's course passes between two gravity hexes, the player chooses which arrow takes effect. A ship moving two hexes a turn which ends its turn in a planet hex may land for one fuel point; a ship moving at a speed of three which ends its turn on a planet hex may land if it can perform an overdrive manuever.

Example One

In this example, the course of an X-24 traveling five (!) hexes a turn just impinges on a planet diagram. (This includes the effect of the gravity hex it entered last turn.) The player must first roll to see if the ship is damaged or destroyed on the Fast Aerobreaking Table. If the ship survives, it immediatly picks up the vector shown in the checked gravity hex. Its new course takes it "straight ahead" three hexes. The gravity hexes the X-24 passes through on this turn effect it next turn.

Example Two

On the previous turn, an X-24 enters a gravity hex, heading straight for a planet. On this turn, its initial velocity and the gravity vector create a course which takes it straight across a planet diagram. The ship must apply an aerobreaking maneuver. The next gravity arrow the ship encounters points back the way it came; the resulting vector puts the planet directly on the planet hex. (Presumably, skimming the atmosphere or in a low orbit.) If the player wishes, the ship could make a burn and land.

On the next turn, the ship is essentially in the same state as a vessel which has just taken off, traveling into an orbit hex at a velocity of one. It must make a burn to enter orbit.

DIAGRAM STILL NEEDED HERE - coming soon, honest.

Aerobraking at high velocities is dangerous. If the ship is moving four or more hexes per turn, roll a die:

Fast Aerobraking table
Die Roll  Result
     1    -
     2    -
     3    -
     4    D1
     5    D2
     6    E

If the ship survives a fast plunge through the atmosphere, its velocity is changed as described above.

An orbiting X-24 can land on any world with an substantial atmosphere (Earth, Venus, and post-terraform Mars) without expending a fuel point; the player merely announces that the ship is landing.

(A fun "special" for the patrol. The X-24 - the name comes from a goofy model rocket - would cost a little more than a corvette. Aerobraking is a legit space technology that NASA plans to use for many future probes, in lieu of expensive braking thrusters.)

Gravitron Q-13

The Gravitron Q-13 is a modified frigate that utilizes an experimental gravity drive. The Gravitron has a fuel capacity of just 10; other statistics remain the same.

The Gravitron can ignore, double, or reverse gravity arrows. When it ignores a gravity arrow, simply treat the arrow as though it were empty space. (Note that gravity must be active in order to start or maintain an orbit!)

Doubled gravity effects the ship twice as strongly; the ship's course would be changed by two in the direction of the gravity arrow. A partial gravity arrow would be treated as a full arrow in this case. The sun's double gravity would be treated as a quadruple gravity arrow!

Reversed gravity arrows have opposite their usual effect on the ship's course, repelling the ship away from the world the arrow belongs to.

The Q-13 must still use a fuel point to lift off of a planet's surface; once in space it may ignore (or reverse!) the gravity hex it launched into and accelerate away. It may land without fuel expenditure, however.

The Q-13 can safely change one gravity arrow per turn. It may attempt to change more; for each additional change roll a die. On a roll of 1-2 the Q-13 is disabled for that many turns. On a roll of 6 the Gravitron Q-13 either turns into a pin-head sized chunk of neutronium or explodes like a nuke. (Flip a coin to see which. It IS an experimental drive!) The effects of the roll are applied before the gravity change is made.

(Another experimental ship for the Patrol, inspired by Larry Niven's "gravity polarizer." Like the X-24, it clicks in well with Tripe's movement system. It should make some really keen maneuvers possible; a slingshot effect off the sun could really make you tear. If the planets are aligned right the Q-13 could play gravity-well billiards across the whole system! I haven't had a chance to test this one . . . )

The Shuttle

Shuttles are large but short-ranged ships used to pick up and deliver cargoes to orbit. Shuttles are also found on the Earth-Luna run and plying the spacelanes between the moons of Jupiter. They often use boosters to help them out of gravity wells.

Combat: 1d
Fuel:   5
Cargo:  50 (or 10 for passenger model)
Crew:   2/5
Passengers: 10 (or 100 for passenger model)

Shuttles have limited life support systems. If they remain in space for more than five turns, the systems may break down. Roll a die each turn after the limit is passed. On a roll of 6 the crew of the ship asphyxiate, leaving the shuttle a derelict. The life support systems are recharged during minor maintenance.

(An interesting "desperation vessel." They might make neat rebel torpedo boats.)

Space Tug

Space tugs are expensive, sturdy civilian ships designed to grapple with and tow disabled vessels. They can perform two overload maneuvers without penalty between maintenance; additional overload maneuvers may be made, but these carry a risk of burning out the tug's engines. Roll on the asteroid collision table each time an additional overload manuever is attempted.

Combat: 1d
Fuel:   10 (20?)
Cargo:   5
Crew:   2/4
Passengers: 2

Towing: Tugs (and other vessels) can grapple with other ships and attempt to pull them out of danger. Linked ships count as one large vessel for maneuvering purposes; the towing ship must perform an overload maneuver to give the pair one normal vector change. Normal thrust lets the pair change course by one hex every other turn; the direction of the change must be announced in advance (the towing ship must thrust in the same direction for two days to have an effect).


Lifeboats are tiny "disposable" ships carried by larger vessels for use in emergencies. They disappear when the lifeboat lands on a planet, or if the inhabitants are rescued by another ship.

Combat: 1d
Fuel:   3
Cargo:  1
Crew:   1/2
Passengers: 6

Lifeboats have heavy-duty foam heat shields, and can perform a limited version of Aerobraking. They can safely land on any planet with an atmosphere without expending a fuel point. To do this the lifeboat must be in orbit, or have a course that intersects the planet while moving at a speed of one. Lifeboats doing this are "used up;" what's left is only usable as a emergency shelter.

Lifeboats are instantly destroyed by any Dx combat result. They have no detection capabilities, but they are so small and insubstantial that they cannot be detected much of the time. (Roll a die for each turn that a lifeboat is in detection range of a planet or ship. On a roll of 1-4 the lifeboat goes undetected.) Lifeboats which want to be detected can take advantage of a manually-operated emergency beacon.

(A gimmick for long campaigns or scenarios involving lost princesses or somesuch.)

Boarding Rules

Sometimes the inhabitants of a disabled ship put up a fight when boarded. Use these rules to see how the defenders fare. Each side rolls a die and adds the combat factor of their ship. The defender subtracts turns of disablement remaining. Patrol ships may add 1 to the roll (heroic space marines). Defending dreadnaughts (which still have their guns) get a bonus of +4. Subtract the defender's roll from the attacker's. Consult the chart below:

-6 or less: The defenders turn the tide! They capture and disable (D1) the attacking vessel. Half of the attackers and defenders are killed.

-4 to -5: All defenders killed in fierce resistance; they can destroy cargo, kill prisoners and disable their vessel if they wish. Half of the attackers killed.

-2 to -3: Defenders put up fierce resistance. They have time to destroy cargo and kill prisoners. Half of the defenders and attackers are killed.

-1 to 1: Defenders put up a good fight, but lose half their number. Attackers lose one quarter of their boarders. Defenders don't have time to destroy cargo or kill prisoners.

2 to 3: Defenders lose a third of their numbers. Attackers suffer no losses.

4+: Defenders overwhelmed. All aboard are captured (alive, if not uninjured).

Triplanetary Map Notes

The Triplanetary map board depicts Earth's solar system. Each hex is approximately 9.3 million miles across. Near the center of the board is Sol (the sun); this is the only body on the map which does not move during the course of a game. The orbital paths of five planets, plus some asteroids, are also shown; counters representing the planets (and their moons) move along these paths during the course of the game.


The "corners" of the planets' hexagonal orbits are numbered. For each planet or asteroid, roll a die. The result of the roll indicates the approximate location of the world at the beginning of the scenario. To find the exact location, roll another die and count that many hexes counterclockwise along the orbit from the corner indicated above. Center the planet's marker on this hex. (Only part of Jupiter's vast orbit is shown; roll a die and place Jupiter that many hexes counterclockwise from the Jupiter symbol printed on the map.)

The counter for Luna, Earth's moon, should be placed on Earth's orbital path, three hexes ahead or behind Earth. (For simplicity's sake, Luna orbits along Earth's path.)

The counters for Jupiter's moons (Io, Callisto, Europa and Ganymede) are randomly placed around Jupiter. Io and Europa should be centered two hexes away from Jupiter. Callisto and Ganymede should be placed three hexes away from Jupiter. Overlapping gravity hexes should be avoided where possible.

Music of the Spheres The planets and asteroids move counterclockwise along their orbits. The planets do not move every turn. The chart below shows which worlds move on a particular day (game turn); an "x" indicates the planet moves, a "." means it stays still. When the end of the turn is reached, start over with Day 1.

Planet                        Day (Game turn)

              1  2  3  4  5  6  7  8  9  10  11  12  13 14  15
Mercury       .  .  .  x  .  .  .  x  .  .   .   x   .  .   .
Venus         .  .  .  .  x  .  .  .  .  x   .   .   .  .   x
Earth         .  .  .  .  .  x  .  .  .  .   .   x   .  .   .
Mars          .  .  .  .  .  .  .  x  .  .   .   .   .  .   .
Asteroids     .  .  .  .  .  .  .  .  .  .   x   .   .  .   .
Jupiter       .  .  .  .  .  .  .  .  .  .   .   .   .  .   x

(Chart and concept adapted from "The Bored Board" by Kevin J. Pardus, The Space Gamer #9, pp. 8-9)

When a planet moves, ships on its surface or in orbit move along with it. Any moons are moved along with the planet, keeping their distance between the bodies constant.

In very long games, orbital motion may result in Jupiter or the asteroids moving off the edge of the map. If this event occurs, "set back the clock" by moving all worlds back several hexes in their orbits; units in deep space must also be moved and their courses redrawn, keeping their relationship to each other and the planets intact.

Intersecting Gravity Hexes If a ship enters a hex with two gravity arrows, it is affected by the arrow belonging to the world his ship is passing closest to. If the ship's course passes through the center of the hex, the player chooses which gravity arrow affects his ship.

Big Map Considerations I've been experimenting with a "big map," two 22 x 17" sheets of hex paper covered with clear "contac" paper. If you ignore the wrinkles and bubbles that always seem to occur, the map is quite nice. I fit in complete orbits of everything out to Vesta (my realistic replacement for Clandestine), plus a large enough chunk of Jupiter's orbit to last many turns. I made planet counters out of "megahexes" (seven hexes in a circle) of the same hex paper as the map, backed with cardboard and covered with clear contac. The counters show the planet and its gravity hexes. The counters would move along the appropriate orbit line, slowly turning so that their sensor footprint sweeps the heavens around them.

Problems: The Moon (ours, Luna) "orbits" three hexes away from Terra. Venus and Earth's orbits are two hexes apart (twenty million miles). It's possible for Venus to be closer to Earth than Luna! And if Luna "orbits" Earth, it's possible for it to collide with Venus! This might make for an interesting evacuation scenario, but is otherwise silly. I guess the Moon will have to stay starward of Earth. Similar problems occur if the Galiliean moons orbit Jupiter.

Trade and Commerce

Players can earn KCr by transporting cargo and passengers.

Special Ship Attributes

This scenario adds some attributes to each ship type. Consult the table below.

Crew has a double listing. The first figure, before the slash, is the absolute minimum number of people needed to run the ship at full capacity. Ships with less than this minimum can not do more than one action (Firing guns OR maneuvering OR repairing damage OR launching ordnance) in one turn. (There must be at least one crewman, of course.) The second listing is the normal complement of crewpeople; leaving port without this number is a civil misdemeanor. Each crewperson has appropriate accommodations. Crew places cannot be used for paying passengers.

Passenger spaces can be used for actual paying passengers, soldiers or even prisoners. Most paying passengers actually require more than one passenger space.

Freighter      2/4             4
Tanker         2/4             4
Liner          2/5            60
Packet         2/5             4
Corvette       3/7             6
Corsair        3/12            8
Frigate        4/15            8
Dreadnought    5/20           12
Torch          4/15            6
Orbital Base   4/20           18

Trade Values

Each planet and moon has a unique trade value used to determine the value and availability of cargo consignments and tour groups of passengers.

PLANET         Trade Value
Mercury              3
Venus                1 (3)*
Earth                4
Luna                 1
L-5                  3
Mars                 2 (3)*
Ceres                2
Vesta                1 ***
Clandestine          1
Io                   1
Callisto             2
Ganymede             3

* Trade values for Venus and Mars increase after they are terraformed.

** Vesta has a ''boom and bust'' economy. Its trade value changes frequently. At the beginning of every month (30 turns) of play, roll a die. On a roll of 1-3, Vesta's trade value is 1. On a roll of 4-5, the trade value is 2. On a roll of 6, the trade value is 3.


Players who have ships which are in port during the commerce phase can have their crews look for a cargo for their next destination. Total the trade values for the origin world (the planet or moon the ship is on) and the destination world (where the ship is heading next). Roll two dice for each ship searching for cargo: On a roll equal to or less thanthe combined trade value of the planet, an interesting cargo is available.

Cargo Availability

Lengthy Search: Increase the planet's effective trade value by 1 if the crew spends the entire turn in port searching for cargo.

Advertising: Increase effective trade value by 1 if the player spends 1 KCr on advertising. (Spending more than one 1 KCr has no effect.)

Merchant Skill: Increase effective trade value by 1 if the captain of the ship can pass a Merchant skill roll.

Size of Cargo

Roll 3 dice and add the trade value of the destination world to determine the size, in tons, of the cargo. If two or three of the dice come up the same number, add and roll those dice over. Keep adding and rolling if the dice continue to come up with the same numbers.

Example: Merv came up with a triple 3 when rolling to determine the size of a cargo he's shipping from Venus to Earth. The basic size is 13 (3 x 3 + 4), but because he rolled triples he rolls all three dice again. This time the dice come up 1-1-3. The size of the cargo goes up to 18, and Merv rolls the two dice that came up 1 once more. This time he gets a 7 and a 6. The total size of the cargo is 31 tons!

Shipping Fee

What a ship earns for carrying cargo depends on the distance it must be carried, its mass and the importance of the shipment.

Distance      Basic fee/ton
In-hex         .75       (i.e. Earth to Luna, Io to Callisto)
1-5 hexes      1.5
6-15 hexes     2
16-25 hexes    2.5
26+ hexes      3

Speed Required

All cargoes must be delivered by a certain date. Some classes of delivery allow for a leisurely trip, perhaps with stops along the way. To find the date, roll two dice and consult the table below. ''D'' in the formula below stands for distance between the worlds. ''N'' stands for the current date. If the cargo is not delivered in the allotted time, the ship's owner is penalized half the agreed-upon fee. For every day after the first day late, the owner is penalized another 5% of the shipping fee.

Die roll  Cargo Class    Deliver by:    Fee Multiplier_
  2-4     Bulk Freight   N + D * 4       .5
  5-9     Standard       N + D * 1      1
  10-11   Rush           N + D *  .75   1.5
  12      Express        N + D *  .5    2

Special Conditions

Roll 2 dice on the table below to see if the cargo requires special protection. Guards may be armed characters or hired guards; two guards, plus one extra for every 10 tons of cargo, are required. Armed ships are those with a non-D combat factor. Armed escorts must include at least one ship with guns; the escort must spend the whole trip with the escorted vessel.

Die Roll      Condition                Fee multiplier
     2-8       None                          1
     9         No passengers aboard          1.1
     10        Guards required               1.25
     11        Ship must be armed            1.5
     12        Ship must have armed escort   2

Example: It is turn 28. Merv's 31-ton cargo must be delivered to Earth, a rare 5 hexes distant. The basic fee is 1.5 KCr per ton. Merv rolls a 7 on the Speed Required table and finds that the cargo is due on Earth in 5 turns, on turn 33. He rolls on the special condition chart and finds that there are none. He earns only the basic fee for his efforts, or a total of 46.5 KCr.

Harry, whose packet Spectra is currently on Earth, has a 9-ton cargo headed for Ceres. The asteroid is currently 12 hexes distant. The basic fee for shipping the cargo is 2 KCr per ton. Harry rolls a 11 on the Speed Required table; the ship must get to Ceres in (15 * .75 =) 11.25 turns, or day 39. The basic fee is multiplied by 1.5 to 3 KCr per ton. Finally, Harry rolls a 11 on the Special Conditions roll. The ship must be armed; fortunately the Spectra is. The fee is multiplied by 1.5 again. The final fee per ton: 4.5 KCr. The cargo will earn Harry 40.5 KCr.

Value of Cargo

It's usually none of the shipper's business what the value of a cargo is. But if the shipment is pirated, destroyed or sold by a dishonest captain, knowing the price of the cargo is important. Roll 3 dice, adding and rerolling on doubles and triples as noted above. Add the trade value of the origin world.

Subtract the size of the cargo divided by 10, rounded down (bulky items tend to be of lesser value). This is the value of the cargo per ton.

High-priority cargoes are obviously of higher value. Multiply them by the same fee multipliers given above for Speed Required and Special Conditions.

Example: Merv rolls three dice to determine the value of his 31-ton cargo. The roll comes up 9 (3-5-1, so there are no rerolls). He adds 2 because the shipment originates at Ceres. He subtracts 3 because the shipment is 31 tons (31/10 rounded down). The value of the cargo is 8 KCr per ton, or 248 KCr for the whole shipment.

Harry rolls a 13 for the basic value of his 9 ton, Ceres- bound shipment. This is increased to 17 because it is originating on Earth. The delivery date requirement increases the value to (17 * 1.5=) 25.5. The armed-ship requirement bumps up the value to (25.5 x 1.5=) 38.25 KCr per ton, or 344.25 KCr!


Passenger Classes

There are several classes of passenger fare. Each requires a certain delivery date and a set number of passenger spaces per passenger. Faster trips, and those that require lots of space per passenger, also bring in more money!

Class              Delivery date  Space     Fare multiplier
Steerage            N + D * 3        1             .5
Slow Boat           N + D * 3        1.5           .75
Coach               N + D * 1        1.5          1
Luxury Class        N + D * 1        2            2.5*
Coach Express       N + D *  .75     1.5          2
Deluxe Expresse     N + D *  .75     2            5*
Solar Comet         N + D *  .5      1.5          3
Grande Expresse     N + D *  .5      2            8*
     * Only Liners and Packets (if they have the room) may accept
passengers of this class.

Special Conditions

Roll 2 dice on the table below to see if the passengers require special conditions. Guards may be hired guards or armed characters; two, plus one more for every three guarded passengers, are required. Armed ships are those with non-D combat factors; escorts must be armed ships.

Die Roll    Condition                     Fare multiplier
  2-5     Super Saver. No late fee.          .75
  6-9     Nothing special                    1
  10-11   Guards required                    1.25
  12      Armed ship/escort required         2

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