Need Help on "Semi-Hard" Classic SF Spaceship Design

Pursuivant · 04-20-2022, 09:52 AM

One of my back-burner projects is GURPSifying the Sector General books.

I've got a good handle on all aspects of the setting except for the spaceship designs.

My attempts to use GURPS Spaceships result in ships that are either way too big for what's described in the source material, don't have sufficient speed to match described performance, or have insufficient range or duration due to insufficient fuel tanks.

I'm assuming a Safetech/Retrotech TL9 setting for most TL, but the spaceship designs and "rubber SF" gear seem "happiest" at TL11^.

The books use a weird mix of hard and soft-boiled SF tech - reaction torch drives for sub-light and atmospheric maneuvering, "cold" reaction thrusters for low-speed space maneuvers, contragravity for low altitude atmospheric maneuvers, and hyperdrives for FTL travel. Fuel type for torch drives isn't specified but it exists.

Ships use torch drives or contragravity to take off from the planet and get into orbit, then use torch drives and constant acceleration to get sufficient speed and distance from nearby objects, and then jump into hyperspace. Sub-light speed and ship orientation is preserved in hyperspace but vector is not.

At the end of the trip the ship drops out of hyperspace, corrects course as needed, then decelerates until it reaches its destination. Landing is via some combination of wings, contragravity, and/or torch drives.

The "feel" of the ships is Golden Age SF: massive, heavily-built ships built using steel and light alloys, huge computers and communications arrays, and bullet- or dart-shaped aerodynamic lines.

Ship performance is comparable to anything from Star Trek or Star Wars. A fast ship can get from the habitable zone of a planet to its Oort cloud in just a few hours then jump to any place in the galaxy in less than a day.

Hyperspace performance is reminiscent of Traveller Jump Drives but power comes from a fusion powerplant, each leg of a hyperspace journey takes a day or less, and range is unlimited given accurate maps. Practically, this means you can jump to anyplace in the galaxy but the rest of the universe is terra incognito.

Four hours of constant burn is repeatedly described as the time needed to get away from the mammoth Sector General space station prior to safe hyperspace jump. There's the strong implication that a ship's speed when it enters hyperspace is a significant fraction of light speed.

Rescue ships are very fast - capable of getting to any place in the galaxy in a few hours - but can't remain on station for more than a week or so. During this time they can burn a lot of reaction mass with sublight maneuvers. Ship's crew is just 4 people, plus 3-4 medics or space salvage crew and space for 20+ sickbay patients in the equivalent of Automed beds.

Scout ships are capable of long-term, long-range galaxy survey operations while carrying a 4-person crew. They're lightly armed but reasonably tough and are capable of planetary landings using reaction drives. I assume they accelerate to a given speed and then coast along a set course, scanning everything as they go.

Warships are humongous, armed with missiles and tractor-pressor beams, and very tough to destroy. They can take smaller ships in tow using tractor beams, even taking them into hyperspace with them. They also have impressive contragravity which allows them to hover in a planetary atmosphere. In wartime they carry massive crews capable of boarding actions. In peacetime, they act as fast colony support and transport ships. Think battleships but with short- to medium-range medium-caliber guns.

Common ship design features are: Aerodynamic Lines, Steel or Light Alloy Armor, Contragravity, Giant Computers and Electronics Arrays, limited Force Fields (only deflect physical objects not energy), Fusion Powerplants, Hyperdrives, Tractor Beams, "Hot" Torch Drives, and "Cold" Low-Speed Maneuvering Thrusters.

I've modified the standard Fusion Torch drive so it gives 5G acceleration and 150 mps delta-V. Sensor Array ratings are reduced by 1 to reflect increased bulk.

Weapon stats are nerfed to make space combat into short-ranged maneuver-based slugging matches and to encourage boarding actions.

04-20-2022, 09:52 AM	#1
Pursuivant Join Date: Apr 2005	Need Help on "Semi-Hard" Classic SF Spaceship Design One of my back-burner projects is GURPSifying the Sector General books. I've got a good handle on all aspects of the setting except for the spaceship designs. My attempts to use GURPS Spaceships result in ships that are either way too big for what's described in the source material, don't have sufficient speed to match described performance, or have insufficient range or duration due to insufficient fuel tanks. I'm assuming a Safetech/Retrotech TL9 setting for most TL, but the spaceship designs and "rubber SF" gear seem "happiest" at TL11^. The books use a weird mix of hard and soft-boiled SF tech - reaction torch drives for sub-light and atmospheric maneuvering, "cold" reaction thrusters for low-speed space maneuvers, contragravity for low altitude atmospheric maneuvers, and hyperdrives for FTL travel. Fuel type for torch drives isn't specified but it exists. Ships use torch drives or contragravity to take off from the planet and get into orbit, then use torch drives and constant acceleration to get sufficient speed and distance from nearby objects, and then jump into hyperspace. Sub-light speed and ship orientation is preserved in hyperspace but vector is not. At the end of the trip the ship drops out of hyperspace, corrects course as needed, then decelerates until it reaches its destination. Landing is via some combination of wings, contragravity, and/or torch drives. The "feel" of the ships is Golden Age SF: massive, heavily-built ships built using steel and light alloys, huge computers and communications arrays, and bullet- or dart-shaped aerodynamic lines. Ship performance is comparable to anything from Star Trek or Star Wars. A fast ship can get from the habitable zone of a planet to its Oort cloud in just a few hours then jump to any place in the galaxy in less than a day. Hyperspace performance is reminiscent of Traveller Jump Drives but power comes from a fusion powerplant, each leg of a hyperspace journey takes a day or less, and range is unlimited given accurate maps. Practically, this means you can jump to anyplace in the galaxy but the rest of the universe is terra incognito. Four hours of constant burn is repeatedly described as the time needed to get away from the mammoth Sector General space station prior to safe hyperspace jump. There's the strong implication that a ship's speed when it enters hyperspace is a significant fraction of light speed. Rescue ships are very fast - capable of getting to any place in the galaxy in a few hours - but can't remain on station for more than a week or so. During this time they can burn a lot of reaction mass with sublight maneuvers. Ship's crew is just 4 people, plus 3-4 medics or space salvage crew and space for 20+ sickbay patients in the equivalent of Automed beds. Scout ships are capable of long-term, long-range galaxy survey operations while carrying a 4-person crew. They're lightly armed but reasonably tough and are capable of planetary landings using reaction drives. I assume they accelerate to a given speed and then coast along a set course, scanning everything as they go. Warships are humongous, armed with missiles and tractor-pressor beams, and very tough to destroy. They can take smaller ships in tow using tractor beams, even taking them into hyperspace with them. They also have impressive contragravity which allows them to hover in a planetary atmosphere. In wartime they carry massive crews capable of boarding actions. In peacetime, they act as fast colony support and transport ships. Think battleships but with short- to medium-range medium-caliber guns. Common ship design features are: Aerodynamic Lines, Steel or Light Alloy Armor, Contragravity, Giant Computers and Electronics Arrays, limited Force Fields (only deflect physical objects not energy), Fusion Powerplants, Hyperdrives, Tractor Beams, "Hot" Torch Drives, and "Cold" Low-Speed Maneuvering Thrusters. I've modified the standard Fusion Torch drive so it gives 5G acceleration and 150 mps delta-V. Sensor Array ratings are reduced by 1 to reflect increased bulk. Weapon stats are nerfed to make space combat into short-ranged maneuver-based slugging matches and to encourage boarding actions.