Steve Jackson Games Forums - View Single Post - [Spaceships] Rocket Boosters and Other Modular Attachments

Seneschal · 03-20-2012, 03:01 AM

I've recently decided that I wanted to make atmospheres and planetary gravity wells a bit more significant in my sci-fi campaign, and to stick with (relatively) non-superscience means of reaching orbit, mostly so that the players wouldn't use their ship (and its 30-ton laser cannon intended for space combat) as they would an attack chopper. It would still be possible for them to land, but to get back up, the players would need help and money - contragravity lifters, a nudge from an electromagnetic catapult, or detachable/reusable rocket boosters. I'd also like to add modular features to spaceships; having recently seen Macross Frontier, I liked the concept of various detachable "packs" that are strapped onto a basic fighter for whatever suits its current mission - extra missiles, extra engines, extra armor, an FTL drive, etc.

Unfortunately, Spaceship's system isn't designed for this - there are no rules for recalculating specs (HP, accel, delta-v) with added mass. There doesn't seem to be a way to attach anything to a ship without counting it as a system or a separate stage, effectively having to redesign the ship every time you strap something temporary onto it.

The rules for towing (under External Clamp, Spaceships p. 15) are the closest alternative, but they have problems - if you have a 100-ton ship with 3G accel, and strap a 30-ton laser onto it, its accel drops to 2.3G. If the laser is functional and works like any other ship system, then this thoroughly breaks the ship design mechanic - a weapon that would take up 6 spaces on a 100-ton ship can now be mounted at the cost of a mere 0.7G.

For a reusable booster to use the towing mechanic (counting it as a ship that clamps onto your ship to tow it), would I add together the "tons of thrust" of the two, and calculate a joint acceleration and delta-v?

Questions:
- The towing rules say nothing about reducing delta-v. Presumably it would be decreased by the same amount as the acceleration (in our above example, the 100 ton ship's delta-v supply would drop by 23%). Though I'm no rocket scientist, so I'm not sure; thoughts?

- If we ignore the engineering problems of designing universal sockets for ships of all shapes and sizes (the setting is not that hard sci-fi), would this essentially circumvent the need for single-piece ships completely?

So, how would you guys handle this? Is there perhaps another ship-design system better suited for this?

03-20-2012, 03:01 AM	#1
Seneschal Join Date: Jul 2009	[Spaceships] Rocket Boosters and Other Modular Attachments I've recently decided that I wanted to make atmospheres and planetary gravity wells a bit more significant in my sci-fi campaign, and to stick with (relatively) non-superscience means of reaching orbit, mostly so that the players wouldn't use their ship (and its 30-ton laser cannon intended for space combat) as they would an attack chopper. It would still be possible for them to land, but to get back up, the players would need help and money - contragravity lifters, a nudge from an electromagnetic catapult, or detachable/reusable rocket boosters. I'd also like to add modular features to spaceships; having recently seen Macross Frontier, I liked the concept of various detachable "packs" that are strapped onto a basic fighter for whatever suits its current mission - extra missiles, extra engines, extra armor, an FTL drive, etc. Unfortunately, Spaceship's system isn't designed for this - there are no rules for recalculating specs (HP, accel, delta-v) with added mass. There doesn't seem to be a way to attach anything to a ship without counting it as a system or a separate stage, effectively having to redesign the ship every time you strap something temporary onto it. The rules for towing (under External Clamp, Spaceships p. 15) are the closest alternative, but they have problems - if you have a 100-ton ship with 3G accel, and strap a 30-ton laser onto it, its accel drops to 2.3G. If the laser is functional and works like any other ship system, then this thoroughly breaks the ship design mechanic - a weapon that would take up 6 spaces on a 100-ton ship can now be mounted at the cost of a mere 0.7G. For a reusable booster to use the towing mechanic (counting it as a ship that clamps onto your ship to tow it), would I add together the "tons of thrust" of the two, and calculate a joint acceleration and delta-v? Questions: - The towing rules say nothing about reducing delta-v. Presumably it would be decreased by the same amount as the acceleration (in our above example, the 100 ton ship's delta-v supply would drop by 23%). Though I'm no rocket scientist, so I'm not sure; thoughts? - If we ignore the engineering problems of designing universal sockets for ships of all shapes and sizes (the setting is not that hard sci-fi), would this essentially circumvent the need for single-piece ships completely? So, how would you guys handle this? Is there perhaps another ship-design system better suited for this?