I checked out the Mothership Kickstarter, and it looks great. A simple D100 roll-under chassis, with some really cool bits added on. But the more I looked at it, I thought "You could do this with the OSR." The premise of the game is Sci-Fi horror, in the lines of Aliens, Prometheus, Pitch Black, Sunshine, etc. and gritty Sci-Fi like Outland, Blade Runner, Soldier, etc.  I'm using Labyrinth Lord as a base. Feel free to contribute anything. Let's see where it can go.

PREMISE

The PCs explore derelict space hulks, doomed colony worlds, eradicate alien infestations, get sent on hopeless missions, etc. Nothing is what it seems, and something always goes wrong. Expect PC death and insanity, it's part of the genre.


CLASSES

Android
"I prefer the term artificial person, myself."

Design: The Android is built using the Dwarf class, since it has Infravision, good saves, some detect powers, etc. 
Bonus: +2 Str, + 2 Con
Weakness: -4 Cha, no emotions
Level 9: You become the leader of a secret android colony that fights for android rights and attract android followers (Sort of like the Dwarf or Elf at Level 9.)


Marine
"We come here, and we gonna conquer, and we gonna kick some, is that understood?"

Design: The Marine is built on Fighter class (obviously.)
Bonus: Once per encounter you can re-roll an attack roll.
Weakness: If you fail a fear save, everyone else is -1 on their fear save.
Level 9: You get command of an attack ship (like the Fighter's stronghold at Level 9.)


Scientist
"By the second day of incubation, any cells that have undergone reversion mutation give rise to revertant colonies, like rats leaving a sinking ship. And then the ship sinks."

Design: The Scientist is built on Thief class, but the thief skills are replaced with genre-appropriate things like analyze, deduction, survival, medicine, etc.
Bonus: Once per encounter you can re-roll a skill roll.
Weakness: Fragile. Make a fear check if a teammate reaches 0 HP.
Level 9: You can create a breakthrough invention, and command a science vessel or station (like the Magic-user at Level 9.)


Technician
"Uh, before we dock, I think we ought to discuss the bonus situation."

Design: This is a catch-all class for the pilot/engineer/spacehand role. It's built on Thief class, but the thief skills are replaced with genre-appropriate things like repair, pilot, jury rig, sabotage, etc.
Bonus: Once per encounter you can re-roll a skill roll.
Weakness: Risk averse. -1 to fear saves if you're facing danger alone.
Level 9: You own a free trader ship and attract a smuggler crew (like the Thief's den at Level 9.)


FEAR

The GM can call for a fear save anytime you encounter a horrific phenomenon. If you fail, you lose d2, d3, or d4 Wisdom (temporary.) The severity of the effect is determined ahead of time by the GM. A natural 1 means you lose the Wisdom permanently and get a phobia or obsession (roll on random chart.) You regain 1 lost temporary point every day after a good night's sleep. Between adventures you recover all temporary Wisdom loss, due to therapy, vacation, etc.


MORALE CHECKS

For NPCs that accompany the players. Each retainer or henchman is linked to a PC. The CHA score of that PC modifies the morale check. Make a check for retainers or henchmen when a PC dies or if half the party is incapacitated. If they fail, they run away. Marines never fail.

Marine:

Marines are trained warriors, elite soldiers always equipped with the most modern weapons and armor. Including exoskeletons, also called power armor.

Class Skills: Communications, Demolitions and Track

Marine exoskeletons themselves generate a certain amount of biogel every day, being able to heal up to 3 health points per level.

Thanks to their training, the Marines receive a +2 bonus to all their saving throws.

Technician:

Technicians are not men of action, and therefore can only wear light armor and cannot use shields, although they do use force fields. However, thanks to their high technical knowledge, they can use all ranged weapons (light and heavy), as well as simple melee weapons.

Class Skills: Science, Computer, Communications, Demolitions, Medicine, Setting / Removing Traps, Repairing and Using Alien Devices.

ST Bonus: ? ? ?

Simulant - Homo Sint:

Your memories are just ones and zeros. You are a machine and they made you look human. They did too good a job. You feel, fear, love and cry. You even dream. The law says you are just a machine. Property. But you know you have a soul like them. The underground got you some forged papers and you went to the border to live free the last of your days. When you die, you will finally know if you really have a soul or not.

Planned Obsolescence: When leveling up or past a certain time roll on a table to see if you've suffered degradation.

Designed - During character generation, the player can repeat a skill score and get the best result.

Made to Last: Simulants are tougher than normal flesh and blood. They gain a +2 bonus to saving throws against poison, disease, and drugs. When a Simulant character gains a level, he can reroll one of his Hit Dice and take the highest number.

Check out Hulks & Horrors.

Quote from: S'mon on November 05, 2021, 03:52:06 AM
Check out Hulks & Horrors.

Or the Hostile setting for Cepheus Engine.

Quote from: jeff37923 on November 05, 2021, 05:58:22 AM

Quote from: S'mon on November 05, 2021, 03:52:06 AM
Check out Hulks & Horrors.

Or the Hostile setting for Cepheus Engine.

Yes to both.

Quote from: GeekyBugle on November 05, 2021, 01:01:47 AM
Simulant - Homo Sint:

Your memories are just ones and zeros. You are a machine and they made you look human. They did too good a job. You feel, fear, love and cry. You even dream. The law says you are just a machine. Property. But you know you have a soul like them. The underground got you some forged papers and you went to the border to live free the last of your days. When you die, you will finally know if you really have a soul or not.

Planned Obsolescence: When leveling up or past a certain time roll on a table to see if you've suffered degradation.

Designed - During character generation, the player can repeat a skill score and get the best result.

Made to Last: Simulants are tougher than normal flesh and blood. They gain a +2 bonus to saving throws against poison, disease, and drugs. When a Simulant character gains a level, he can reroll one of his Hit Dice and take the highest number.

I like your design here, especially Planned Obsolescence.