David replied to me: > >> The exhaust from > >> fusion rockets needn't be terribly radioactive. A D-3HE fusion > >> reactor is fairly low radiation output. > >> David Scheidt > >> [email protected] > > > > Talking about radiation, "fairly low" doesn't sound all that > > reassuring, expecially if space traffic starts to rival air > > traffic today. Consider what happened to nuclear freighters. > > It really matters what kind of radiation you're talking about. A > D-3He fusion reactor uses two inert (well, one of them is inflammable) > gases as fuel. The primary products are heat, a proton, an alpha > particle, and some X rays. Most of the Xrays will be absorbed by the > shell of the reactor, as they're radiated pretty equally in all > directions. One end of a fusion rocket is open, so there will > escaping Xrays in that direction. They'll get absorbed (as heat) by > the atmosphere in less distance than the exhaust will kill anything > the plain old-fashioned way: by setting it on fire. The proton and > alpha particle will be indistinguishable from the very high > temperature air or other reaction mass that's being shot out the back. > There are essentially no long-lasting sources of radiation there. > Setting things on fire is much more of a problem. The exhaust > temperature is very high. For things that act something like > airplanes (with wings or lifting bodies) they can use the air-ram as a > sort of ducted fan until they're well air borne, and then turn on the > full power. > > Fission reactors, on the other hand, produce lots of particles that > hang around and emit radiation for (days/months/years/centuries), > depending on the particular reactions involved. (They could be used > in a fully-closed thermal only mode, but I don't think they'd produce > enough thrust that way.)
Once upon a time, I wrote those. For frontier operations, they have vectored thrust, despite the fact that they fry the landing zone. I figured that you could come down with a light touch, and never take off twice from the same spot. I kind of dodged the question if a fusion air ram (and a fusion ram rocket) is supposed to be an pure ramjet. If so, it only works over 375 mph, and the initial acceleration must come from a water-based fusion rocket. Pure fusion rockets are considerably lighter than combined fusion ram rockets (which are again lighter than separate fusion rockets and fusion air rams). So there could be a variety of different designs ... * Shuttles with fusion ram rockets and pure fusion rockets (which gain a little bit of payload if they go straight up). * Landers for atmosphere-less moons. * OTVs with high-thrust/low-impulse or low-thrust/high-impulse engines, depending on how long the payload can wait. * Long-range interplanetary craft. * Expensive and low-payload surface-to-surface interplanetary craft. Tatsu-Class Spaceplane v1.0 (TL10) Copyright 2003 by Onno Meyer The Tatsu was produced on Baridi Dania from 5198 to 5216. A few remain operational to this day, often as an utility craft on small interstellar ships. The spaceplane can carry two crew and up to ten passengers or the equivalent amount of cargo. The fusion engines can use the atmosphere of a planet or water from the tanks (at 13.34 gallons per minute) as their reaction mass. This gives the Tatsu a better atmospheric endurance than most other landing craft. Subassemblies: Body +4, two STOL Wings +2, three Retractable Wheels +1. P&P: Two 20,000-lb. vectored fusion ram-rockets, 50-kW RTG, three 360,000-kWs rechargeable power cells. Reaction Mass: 600 gallons water. Occ: 2 CCS, 10 folding CS Armor F RL B T U All: 4/100 4/100 4/100 4/100 4/100 Equipment Body: Two 500,000-mile radios; 5,000,000-mile tight-beam radio; 1,000,000-mile laser communicator; four 50x LLTVs (+5/+10) [Bod:FBTU]; two 50-mile AESAs (scan 21) [Bod:FB]; two 50-mile PESAs (scan 21) [Bod:RL]; 50-mile radscanner (scan 21); low-resolution planetary survey array; two sets of precision navigation instruments; IFF; two inertial navigation systems; terrain-following radar; four C5 hardened minicomputers; two terminals; cartography (C4); damage control (C4, +4); database (C1, 1 GB manuals); datalink (C1); routine vehicle operation (C5, skill 15); two socket interfaces; compact fire suppression system; cargo ramp; one-man airlock with decontamination shower; high-security alarm; refueling probe; toilet; two 12x1 man-day limited life systems; 12 crashwebs. External (on wheels): Puncture-resistant tires. Statistics Size: 30'x20'x10' Payload: 1.2 tons Lwt: 10 tons Volume: 1,045 cf Maint: 8 man-hours Price: $2,667,550 HT: 10. HP: 450 Body, 113 each Wing, 50 each Wheel. gSpeed: 555 gAccel: 30 gDecel: 10 gMR: 0.5 gSR: 4 Ground Pressure Very High. 1/8 Off-Road Speed. aSpeed: 2,000 aAccel: 40 aDecel: 14 aMR: 4.5 aSR: 6 Stall Speed 0. sAccel: 2 G sMR: 2 Delta-V 38 mps. Design Notes Body is 900 cf. Wings are 50 cf. Wheels are 45 cf. Structure is light, standard, responsive, with superior streamlining, heavy compartmentalization and automatic variable-sweep wings. Armor is advanced composite. Structure is self-sealing. Duplicate computerized controls. Tanks are standard, wing-mounted. There are 128.3822 cf of empty space in the body and 5 cf of empty space in each wing. Empty weight is 12,500 lbs. The TL10 vehicle uses Vehicles [2nd edition, 3rd printing, July '02 errata] and Vehicles Expansions 1 and 2. Scout Shuttle v1.0 (TL10) Copyright 2004 by Onno Meyer The scout shuttle carries small teams from an orbiting starship to the surface of a planet. In addition to two pilots, the shuttle has room for eight scientists and their two scout buggies. Maintenance and janitorial tasks are handled by swarms of microbots. The fusion ram-rockets can use either the atmosphere or water from the fuel tanks as reaction mass. In vacuum, they use 100 gallons per minute, for one hour at full thrust and a delta-V of 114 km/s. Subassemblies: Body +6, four Skids +2. Powertrain: Four 75,000-lb. vectored fusion ram-rockets; 1,000-kW fusion reactor; twelve 360,000-kWs rE power cells. Fuel: 6,000 gallons water. Occ: 10 bridge RCS, 10 bunks Cargo: 590 cf Armor F RL B T U All: 4/100 4/100 4/100 4/100 4/100 Equipment Body: Two extreme-range radios with scrambler; long-range tight-beam radio with scrambler; long-range laser communicator; two medium-range neutrino communicators; six 15x LLTVs [Bod:FRLBTU]; two 160-mile AESAs [Bod:FB]; 800-lightsecond FTL radar; two 160-mile PESAs [Bod:RL]; 160- mile multiscanner; medium-resolution planetary survey array; meteorological instruments; two flight recorders; navigation instruments; two transponders; two inertial navigation systems; three C5 hardened minicomputers; ten terminals; ten socket interfaces; compact fire suppression system; two cyberswarm hives (armored crawler, rechargeable AA cell, cleaner swarms); four cyberswarm hives (armored crawler, rechargeable AA cell, repair swarms); two cyberswarm hives (flyer, rechargeable, AA cell, medical swarms); two cyberswarm hives (flyer, rechargeable AA cell, pesticide swarms); automed; cargo ramp; 4- man airlock with decon shower; high-security alarm; refueling probe; 10 man-day limited life system; 10-man full life system; ten G-seats. External: Radiation shielding. Statistics Size: 45'x30'x12' Payload: 30 tons (incl. fuel) Lwt.: 60 tons Volume: 8,000 cf Maint.: 13 man-hours Price: $6,934,375 HT: 11. HPs: 3,750 Body, 150 each Skid aSpeed: 2,120 aAccel: 50 aDecel: 10 aMR: 2.5 aSR: 4 Stall Speed 0. sAccel: 2.5 G sMR: 2.5 delta-V 255,469 mph. Design Notes Body is 8,000 cf; skids are 400 cf, retract into body. Structure is medium, standard, with very good streamlining and a lifting body. Armor is advanced composite. Sealed structure. Dual computerized controls. Ultralight, self-sealing tanks. 31.44 cf of empty space. Empty weight is 60,000 lbs. The TL10 vehicle uses the design rules from Vehicles [2nd edition, 3rd printing, July '02 errata], Robots, VXi and VXii (including the optional armor volume rule) with the text format from Vehicles Lite. VTOL Aerospace Fighter v1.0 (TL10) Copyright 2007 by Onno Meyer Jack of all trades and master of none, the VTOL Aerospace Fighter can operate from ships in orbit or from surface bases. It is armed with 4.8 tons of bombs or missiles and two point defense lasers. All ordnance is carried internally to preserve stealth and speed. The pilot and copilot are shielded by the reaction mass tanks - they have to rely on sensors rather than unaided vision. In space, the fusion rockets use 2,400 gallons of water per hour. Subassemblies: Body +5, three retractable Wheels +2. Powertrain: Two vectored 60,000-lb. fusion ram-rockets; 200-kW RTG; 24 360,000-kWs rechargeable power cells. Fuel: 2,400 gallons water. Occ: 2 NCS. Armor F RL B T U Body: 4/250 L 4/100 L 4/100 L 4/100 L 4/250 L Wheels: 4/100 L 4/100 L 4/100 L 4/100 L 4/100 L Weaponry 3.6-MJ Xaser [Bod:F] (450 shots) +2. 3.6-MJ Xaser [Bod:B] (450 shots) +0. 9,600-lb. Weapon Bay. Equipment Body: Full stabilization and cyberslave mounts for Xasers; two very long range radios with scramblers; two long range laser communicators; 500-mile LPI AESA; two 2,000-mile thermographs; 500-mile radscanner; flight recorder; two sets of precision navigation instruments; two IFF; two inertial navigation systems; military GPS; terrain-following radar; two HUDWACs with pupil scanners; deceptive jammer (rating 12); 32 aircraft decoy dischargers; two C6 hardened microframes; two terminals; compact fire suppression system; refueling probe; 2 man-days limited life support; crew escape capsule. External: Radical emission cloaking; radical stealth; instant chameleon; puncture-resistant tires. Statistics Size: 40'x20'x10' Payload: 15.2 tons Lwt.: 30 tons Volume: 2,000 cf Maint.: 14 man-hrs. Price: $8,940,110 HT: 12. HPs: 3,000 Body, 300 each Wheel aSpeed: 6,000 aAccel: 40 aDecel: 12 aMR: 3 aSR: 4 sAccel: 2 G sMR: 2 Delta-V: 53 mps Design Notes Body is 2,000 cf with radical streamlining and lifting body. Wheels are 100 cf, retract into body. Structure is heavy, expensive. Armor is advanced laminate. Self-sealing. Computerized controls with duplicate maneuver controls. Ultralight, self-sealing tanks. 18.23 cf of empty space in the body. Empty weight is 29,600 lbs. Weapon Weight Volume Cost Power WPS VPS CPS TL 3.6-MJ Xaser 100 2 $80,000 38,400 - - - 10 Weapon Ammo Malf. Type Damage SS Acc 1/2D Max RoF 3.6-MJ Xaser - ver. imp. 6d*5(2) 20 26 36,000 110,000 4* The vehicle uses the design rules from GURPS Vehicles [2nd edition, 3rd printing, Dec 2004 errata], VXi, VXii (the armor volume rule) and the text format from Vehicles Lite. _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
