For this SF-BRP, I assume a background like the one of Traveller. It is comparable to the universes of Asimov (Foundation) or Anderson (Dominic Flandry) and could be used in any similar background with only little problems.
The background centers around a more-or-less peaceful stellar empire with client states, independent wilds and some non-human races. The empire itself is ruled by beings calling themselves humans. Technology is advanced, but not as sophisticated as you could think of. There is faster-than-light (FTL) travel, there are computers (perhaps also AIs), robots, laser weapons and all the other classical SF-stuff. However, there's no teleportation, antimatter power sources, sun-destroying weapons, cyberware or other 'unbelievable magic-like super technology'.
These are the characteristics of CoC. STR, CON, INT, DEX and APP are all 'classic'. SIZ is typical for BRP-like games and EDU is important for SF games, maybe more than STR or CON (TNE for example uses STR, CON, INT, AGL=DEX, EDU and CHR=APP). POW is useful because it allows the concept of SAN, making a SF/Horror crossover conceivable. POW could also be used for PSI-like magic.
Slightly different characteristic generation should be used for the different races of the Traveller universe. In the templates below, only those statistics which vary from the human norm are listed.
Char. Roll Averages STR 3D6 10-11 CON 3D6 10-11 SIZ 2D6+6 13 DEX 3D6 10-11 APP 3D6 10-11 INT 2D6+6 13 POW 3D6 10-11 EDU 2D6+6 13
STR 3D6+2 12-13 SIZ 2D6+8 15Aslan are honorable lion-like creatures. They are stronger and somewhat bigger than humans. Male Aslan might have an INT of only 2D6+4.
STR 2D6+3 10 CON 1D6+10 13-14 SIZ 2D6+3 10 POW 2D6+6 13Droyne are lizard-like creatures with good PSI abilities.
STR 2D6 7 SIZ 2D6 7 INT 3D6+6 16-17Hivers look like great sea stars.
STR 3D6+2 12-13 CON 3D6+2 12-13Vargr resemble uplifted dogs.
POW 2D6+6 13Zhodani are human like, but most of them can use PSI.
High Gravity +1 STR, -1 CON Low Gravity -1 STR, -1 CON Hostile Atmospheres -1D3 CON, +1D3 DEX* High Population +1D3 APP Low Population -1D3 APP High Tech Level +1D3 or +1D6 EDU Low Tech Level +1D3 CON, -1D6 EDU* Only if environment suits were often worn
Calculate hit points as (CON+SIZ) / 2 (rounding up).
Calculate damage bonus (for melee weapons) as (STR+SIZ) / 5 - 5 (rounding up). Apply normal damage bonus to all melee attacks except bites and other attacks which don't use the full effects of the strength or size. Apply half bonus to thrown weapons and no bonus to missile weapons. If you're stronger, use a heavier missile weapon. Your size isn't important at all.
(In CoC, the difference in skill points between EDU 10 and EDU 20, both usual values, seems to be too unfair. You can be good in a lot of skills without education.)
A character can try to increase his skills by using something I call educational occupations. This could be a technical university, combat training due to military service or war experience, or other special education. It's possible that the character had to make some sort of aptitude test. You gain about 50-100 points.
plus own language (EDUx5) and foreign languages (00).
plus a lot of weapon skills for all hand-to-hand, missile and heavy weapons (such as grenade launchers for example). Handguns (20), SMGs (15), Rifle (25), Shotgun (30), Heavy Weapons (no more than 10).
Pilot (thing) divides into quite a lot of subskills, so they should default to each other at half skill, if both are the same class of things, e.g. water vessels, submarines, space ships (no FTL travel), jump ships (with FTL travel).
(Another suggestion from RQ4, so characters live a little bit longer.)
[Optional] Use the following hit locations, which all have own HPs.
1D20 Hit location Hit points per location (HL) 1-3 right leg HP x 0.33 4-6 left leg HP x 0.33 7-10 abdomen HP x 0.33 11-12 chest HP x 0.40 13-15 right arm HP x 0.25 16-18 left arm HP x 0.25 19-20 head HP x 0.33
1-3 right leg HP x 0.33 4-6 left leg HP x 0.33 7-8 abdomen HP x 0.33 9-10 right wing HP x 0.25 11-12 left wing HP x 0.25 13-14 chest HP x 0.40 15-16 right arm HP x 0.25 17-18 left arm HP x 0.25 19-20 head HP x 0.33
1-3 First Limb HP x 0.33 4-6 Second Limb HP x 0.33 7-9 Third Limb HP x 0.33 10-12 Fourth Limb HP x 0.33 13-15 Fifth Limb HP x 0.33 16-18 Body HP x 0.50 19-20 Head Limb HP x 0.33
1-3 right leg HP x 0.33 4-6 left leg HP x 0.33 7-9 abdomen HP x 0.33 10 tail HP x 0.25 11-12 chest HP x 0.40 13-15 right arm HP x 0.25 16-18 left arm HP x 0.25 19-20 head HP x 0.33A character dies if his head or body (chest or abdomen) loses HP or more points at once.
Healing is as described in CoC. An immediately applied First Aid or Medicine will restore 1D3 HP. Normal healing restores 1D3 per week, plus 1D3 due to Medicine. Because of sophisticated med-tech, the recovery rate may be even higher (another 1D3 per week). All rolls are made per injury.
Acid, Drowning, Suffocating, Explosions, Falling, Fire and Poisoning are as usual as in CoC.
(10 or 12 seconds is too long for firearm combat. Because I didn't change the rate of fire, combat has been speeded up. Decide, whether this is good or bad.)
DEX determines the order of attack. A tie is broken by INT or a D% roll. Firearms go before hand-to-hand combat. Afterwards, firearms with a rate of fire greater than one go again. If one character has a DEX which is more than 10 points greater than the opponents DEX, he can make hand-to-hand attacks before the opponents can react and fire.
You can dodge or parry (use the same skill as for hand-to-hand attack or Brawl skill) as many attacks as you like, but with a cumulative minus of 20% (if you parry) or 30% (if you dodge) for each attack. You can go without defense and make an all out attack, attacking twice. Or, you can defend twice before reducing the skill value and go without an attack.
Laser weapons have a low powered target beam that gives +10% to hit if the user uses it.
Stunner are special non-lethal weapons which stun a target. A pistol emits energy of 3D6 strength, a heavy rifle 4D8. The rolled total is matched against the HP of the target. If the strength of the energy overcomes the HP of the target, the target is stunned for strength x3 combat rounds. Standard range is 5m, up to 10m is damage is halved.
Weapons Base% Damage AP Unarmed 50 1D3+db - Grapple 25 1D4+db - Knife 25 1D3+db 3 Dagger 25 1D4+db 4 Parry dagger 20 1D4+db 6 1H-weapons 20 1D6-1D8 +db 6-8 2H-weapons 15 1D8-1D10+db 8 Shields small 20 1D4 8* medium 20 1D4 10* large 20 1D4 12** this is wood or plastic; metal or other material have higher values (e.g. +2)
Bow 5 1D6 / 1D8 Crossbow 30 1D8 / 1D10 / 2D6 Pistols 20 1D6 / 1D8 / 1D10 / 1D10+2 / 2D6 / 2D8 Rifles/SMGs 15 1D10+2 / 2D6 / 2D8 / 3D6 / 3D8 Shotguns 30 4D6* (reduced due range) Lasers 25 2D4 / 2D6 / 2D8Armor: Absorbs damage. For the snake of simplicity, there are no special penetration rules for crossbows, lasers, etc. If hit locations are used, different locations may be protected by different armor. Some examples:
Leatherjacket 1 Kevlar vest 5 Metal(helmet) 6 Combat armor 10