Steve Jackson Games Forums [Spaceships] Passage Tubes? Stats? Cost?
 Register FAQ Calendar Mark Forums Read

 09-02-2017, 01:29 PM #1 vicky_molokh GURPS FAQ Keeper     Join Date: Mar 2006 Location: Kyïv, Ukraine [Spaceships] Passage Tubes? Stats? Cost? Greetings, all! SS1:42 mentions using a Passage Tube to connect two spaceships, and gives dimensions. How much would one such tube be in terms of cost, mass and DR for various TLs (primarily interested in TL9)? Thanks in advance! __________________ Vicky 'Molokh', GURPS FAQ and uFAQ Keeper
 09-02-2017, 02:01 PM #2 ericthered Hero of Democracy     Join Date: Mar 2012 Location: far from the ocean Re: [Spaceships] Passage Tubes? Stats? Cost? We're looking at around 100 cubic yards of space. Or perhaps 100 square yards of material. Pages 75 and 76 of ultra-tech may help us with costs to fill that space. Our options are: Envirobag Modular Environmental Cage Pressure Tent -- in three sizes. Each of the five options would provide its own point of data. The simplest extrapolation is the cage, of which we require 10. We pay \$100k and haul around 2 tons. I bet the tents give better numbers. And ones that change with TL. EDIT: if we go with the envirobag being fairly roomy (7 feet long and 3 feet in radius), we get much cheaper. \$12k, and 225 lbs if extrapolating volume. 4400\$ and 85 lbs if we extrapolate surface area. __________________ Be helpful, not pedantic Worlds Beyond Earth -- my blog Check out the PbP forum! If you don't see a game you'd like, ask me about making one! Last edited by ericthered; 09-02-2017 at 02:24 PM.
 09-02-2017, 02:21 PM #3 a humble lich   Join Date: Jun 2017 Re: [Spaceships] Passage Tubes? Stats? Cost? In third edition, passage tubes cost \$1000 took 40 cf of space, and weighed 1000 lb and had a DR of 12. Armored passage tubes cost \$1000 more, weighed 2000 lb more and had DR 20. Hope that helps.
 09-02-2017, 02:27 PM #4 ericthered Hero of Democracy     Join Date: Mar 2012 Location: far from the ocean Re: [Spaceships] Passage Tubes? Stats? Cost? That's 67 units to make the full tube. so 67,000 \$ and 33.5 tons. These numbers are all over the place. __________________ Be helpful, not pedantic Worlds Beyond Earth -- my blog Check out the PbP forum! If you don't see a game you'd like, ask me about making one!
 09-02-2017, 03:19 PM #5 a humble lich   Join Date: Jun 2017 Re: [Spaceships] Passage Tubes? Stats? Cost? No, those number were for the full tube. They took 40 cf of space when folded up not in use.
 09-05-2017, 12:26 PM #6 Rupert     Join Date: Aug 2004 Location: Wellington, NZ Re: [Spaceships] Passage Tubes? Stats? Cost? The tube in Spaceships is ~30 yards long, and ~2 yards in diameter. The relevant characteristic for cost, weight, etc. would be surface area, plus a bit extra for the fittings at each end. An open cylinder of this size has an area of about 2 x 3.1416 x 30 = 190 yards^2, or ~1700 ft^2. Relevant comparisons would be Envirobags (but they have insulation that a tube won't need), Pressure Tents (but they have air tanks and locks, so I'll ignore them), and Rescue Bubbles. A sleeping bag or Envirobag probably has a surface area of about 35 ft^2 (4 yards^2). A rescue bubble can be walked in, so is presumably 5' or more in diameter, and thus has a surface area of about 80 ft^2 (9 yards^2). This gives us costs and weights per square yard of: Code: ``` Bag Bubble TL Cost Wt. Cost Wt. 9 \$40 0.75 \$88.9 0.444 10 \$20 0.5 \$66.7 0.333 11 \$10 0.375 \$44.4 0.222 12 \$5 0.25 \$33.3 0.167``` It would appear that the bubble is made of lighter, but rather more expensive materials, which seems fair for something of its nature. For a passage tube that's intended to be light, sealed, and reusable (which a bubble isn't really), I'd be inclined to use the higher of both price and weight, giving this table for the tube: Code: ``` TL Cost Wt. 9 \$17K 140 10 \$13K 95 11 \$8.5K 70 12 \$6.5K 45``` I'd chuck a bit more on for the fittings at each end: Code: ```Passage Tube TL Cost Wt. 9 \$20K 200 10 \$15K 150 11 \$10K 100 12 \$7.5K 75``` Compared to most spaceships, the cost is almost nothing, and the weight likewise. I've always included them as standard equipment that comes with an airlock. Thus a new, or well maintained ship will have one per lock. An old ship, not always kept up to spec, might well not have any, or have one much-patched and sometimes leaky one. If the PCs don't think to check before blasting off into the wild blue yonder, their trip could be more exciting than they anticipated. EDIT: I forgot - DR1, like a rescue bubble. Actual armour would add quite a bit to weight, especially at lower TLs. Hmm. Using UT's armour rules, and assuming a person has a surface area of about 20 ft^2, a layer of standard thickness ballistic cloth (8 lbs, \$1200 for a suit) would add 8 x 1700 / 20 = 680 pounds in weight, and \$102K in price. We can probably halve the cost, because this doesn't have to be cut to fit a human body shape, but the weight wouldn't change. Making it thinner would lighten and cheapen the armour as usual. Any armour will add considerably to the storage volume, as it changes from a thin tube to a rather thicker and less flexible one. I'm happy to assume a DR1 system as the standard, because no sensible DR will keep out debris hitting at the speeds you get from radically different orbits, etc., and a baggy outer skin of mylar+foil will do for micrometeors and the like, while DR1 is enough to survive normal bumps and scrapes. __________________ Rupert Boleyn "A pessimist is an optimist with a sense of history." Last edited by Rupert; 09-05-2017 at 12:42 PM.
 09-05-2017, 12:58 PM #7 Anthony   Join Date: Feb 2005 Location: Berkeley, CA Re: [Spaceships] Passage Tubes? Stats? Cost? Weight actually scales in part with volume, that is probably not very interesting on the scale of a passage tube. In general, the force trying to split apart a circular tube is (tube radius) * (pressure within tube) * (distance over which you are measuring) -- i.e. if the tube is at 0.2 bar (about right for pure oxygen) and a 1m radius, the force trying to split the tube walls is 20,000N/m. If the tube walls have a strength of 200MPa, they need to be 0.1mm thick, and the total wall volume is 6.3e-4m^3/m; assigning a convenient density of 1600kg/m^3, that's about 1 kg/m, or 27 kg (about 60 lb) for the entire tube. This can be adjusted somewhat based on materials and desired safety margin. Note that it can't be collapsed unless the air is drained from it. Based on my experience with collapsing tubes, it's probably around 5% volume when collapsed. __________________ My GURPS site and Blog.
 09-07-2017, 11:59 AM #8 Varyon   Join Date: Jun 2013 Re: [Spaceships] Passage Tubes? Stats? Cost? Armor cost and weight wouldn't be too difficult to work out, using the armor design articles from Pyramid. You're looking at 1700 sf of fabric. There could be a discount for not needing any basic tailoring, but I think it would probably be too small to worry about. At TL 9 you're probably using magnetic liquid armor (high-end reflex armor), for 1088 lb and \$217,600 per point of all-around dDR (dDR is doubled against piercing and cutting attacks). At TL 10, you'd use bioplas, for 765 lb and \$459,000 per point of all-around dDR (dDR is tripled against piercing and burning attacks). At TL 11, you'd actually still be using bioplas, but at half the price. At TL 12, you'd switch to energy cloth, for 238 lb and \$119,000 per point of dDR. There may be a limit to how thick such an armored tube can get before it's unable to be properly retracted, which will result in some sort of maximum DR for each of the above materials, but I'm not certain. __________________ GURPS Overhaul
09-08-2017, 04:33 PM   #9
fredtheobviouspseudonym

Join Date: May 2007
Re: [Spaceships] Passage Tubes? Stats? Cost?

Quote:
 Originally Posted by Varyon There may be a limit to how thick such an armored tube can get before it's unable to be properly retracted, which will result in some sort of maximum DR for each of the above materials, but I'm not certain.
For paranoid space/starship owners you could have nested tubes -- like a hose inside a tire -- each one of which folds separately. Would take up a lot of space as the outer tube would have to fold into a toroidal storage volume around the inner tube's storage area (itself around the hatch).

But it would make the likelihood of puncture (requiring two simultaneous punctures of armored and presumably-self-sealing tubes) very unlikely.

Oh, yeah -- and wear a form-fitting spacesuit with pull-on flexible helmet when you're in the twin tubes.

 Tags docking, passage tube, spaceships

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Fnords are Off [IMG] code is Off HTML code is Off Forum Rules
 Forum Jump User Control Panel Private Messages Subscriptions Who's Online Search Forums Forums Home Illuminati Headquarters     SJ Games Discussion     Daily Illuminator     Forum Feedback and Help Warehouse 23     Warehouse 23 General Discussion     Warehouse 23 Digital     Pyramid Munchkin     Munchkin 101     Munchkin     Munchkin Collectible Card Game     Other Munchkin Games Roleplaying     Dungeon Fantasy Roleplaying Game         DFRPG Resources     GURPS         GURPS Resources         GURPS Character Assistant     Transhuman Space     Traveller     The Fantasy Trip         The Fantasy Trip: House Rules     In Nomine     Roleplaying in General     Play By Post Board and Card Games     Car Wars         Car Wars Old Editions     Ogre and G.E.V.         Ogre Video Game         Ogre Scenarios     Board and Dice Games     Card Games     Miniatures The Gnomes of Zurich     The Industry     Conventions     Trading Post     Gamer Finder

All times are GMT -6. The time now is 04:57 PM.

 -- Default Style ---- Classic Forum Colors Contact Us - Steve Jackson Games - Privacy Statement - Top