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Post by Enderminion on May 10, 2017 2:37:19 GMT
has my ship been added? 60G accel dry and 4 wet Is that an escape ship for criminals? as the manufactuor of my ship, I hold no responsibility for the actions of those who purchused my ship, they need good karma and luck to make it to orbit anyway, as well as a launch with the planets rotation, on the equador, with a tailwind, no clouds, and a low pressure zone, from a mountin
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Post by nerd1000 on May 10, 2017 4:08:11 GMT
Is that an escape ship for criminals? as the manufactuor of my ship, I hold no responsibility for the actions of those who purchused my ship, they need good karma and luck to make it to orbit anyway, as well as a launch with the planets rotation, on the equador, with a tailwind, no clouds, and a low pressure zone, from a mountin couldn't you delete one or two engines and use the weight savings to improve Delta-V? You'd also avoid the suicidal G-forces.
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Post by The Astronomer on May 10, 2017 4:12:39 GMT
as the manufactuor of my ship, I hold no responsibility for the actions of those who purchused my ship, they need good karma and luck to make it to orbit anyway, as well as a launch with the planets rotation, on the equador, with a tailwind, no clouds, and a low pressure zone, from a mountin couldn't you delete one or two engines and use the weight savings to improve Delta-V? You'd also avoid the suicidal G-forces. He's a kerbal engineer. 'Moar boosters' principle is his best friend. In real life, orbital injection stages tend to have low acceleration to save weight.
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Post by Zerraspace on May 10, 2017 15:03:52 GMT
Seeing as I've spent a lot of time studying high-payload launchers and SSTO's for use in the real world, I decided to take a crack at this challenge. This is a very lazy attempt, taking all of 30 minutes to complete, and at a glance is not particularly cost effective relative to most of the other entries, but it does take into account quite a few other factors that I think should give it a special place. It has 700 total capacity, split between 45 crew and 655 passengers, which for a bargain price of 117 Mc translates to a completely affordable 178626 c/passenger, well worth the certainly not-forced recommendation by your travel manager (what's that? Is it business or economy? Economy class, of course!). But that price assumes that the rocket goes up once and never comes back down. This has just enough delta-v to make it into orbit and, by aerobraking most of the rest off, is capable of fully powered touchdown, at which point it can undar ouergo minor maintenance and be refueled to send up again (if you need 9.4 km/s to get into space, and maybe 0.1 km/s to aerobrake for re-entry, that leaves 0.6 km/s for touchdown - SpaceX gets by with 0.4 so that should be good enough). In that case, cost per launch becomes roughly that of the propellant, which, at 2.64 c/kg, becomes 66.158 Mc/launch, reducing cost per passenger to 101005 c/passenger... I can hear the marketing manager campaigning to reduce it to 99999 already in order to attract further deadbea... ahem, customers. Not that such is useful for this challenge, but having reusable SSTO arks would be great for trying to carry this out in real life. Keeping this line of thought, I tried to use conventional materials wherever possible, which is why it uses easy to get and store RP-1 propellant - the only odd thing out are that the tanks have boron walls, because ever since UHMWPE got nerfed, this stuff gets higher mass ratios than anything else, and it's not particularly expensive for this challenge either. The ship uses a thick titanium underlayer as a support; seeing as the space shuttle external tank holds up 2000 tons with 3 mm thick aluminum skin and this ship is 15 times heavier with a 3x stronger material, I could probably get away with only 1.5 cm, but I scaled it to 2.5 because the mass didn't go up all that much. An outer shell of silicon nitride serves as a re-entry shield, with the minimally conductive silica gel underneath ensuring heat is not conducted inwards; its chemical inertness also protects against Earth's increasingly corrosive atmosphere (seriously, you can dunk silicon nitride in near pure sulfuric acid, you'll lose micrometers per year at worst). It might even make a decent whipple shield; and you're going to need one with all these discarded boosters getting left in orbit! And here are the pictures: At just under 190 meters tall and 30 meters wide, this ship is roughly twice the height of the Saturn V and thrice its diameter, yet has ten times the mass and can carry a much larger payload (I'm going to assume that the 6 months' supplies the game figures are allowable cargo). Acceleration of 2.34 g's sounds like overkill, but it's less than the space shuttle at liftoff (3 g's), and high enough to handle gravity losses even if one engine goes out. You'll need to turn the engines down as the ship ascends to avoid knocking out your crew complement. Most of the cost lies in the propellant tanks, which makes me wonder if it's the boron skin or RP-1 - sure, the former is somewhat expensive, but the tanks have a huge mass ratio. You could likely significantly reduce cost by taking off much of the armor and reducing the number of tanks thereafter. Oh, and here are the codes:
PropellantTankModule 25.0 t RP-1 Tank UsesCustomName false Propellant RP-1 StructureComposition Boron ReactionMass_kg 25000 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 100 t RP-1 Tank UsesCustomName false Propellant RP-1 StructureComposition Boron ReactionMass_kg 1e+005 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 250 t RP-1 Tank UsesCustomName false Propellant RP-1 StructureComposition Boron ReactionMass_kg 2.5e+005 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 1.000 kt RP-1 Tank UsesCustomName false Propellant RP-1 StructureComposition Boron ReactionMass_kg 1e+006 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 2.50 kt RP-1 Tank UsesCustomName false Propellant RP-1 StructureComposition Boron ReactionMass_kg 2.5e+006 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
RadiatorModule 2x4 Amorphous Carbon Radiator (Light) UsesCustomName true Composition Amorphous Carbon PanelWidth_m 1 Height_m 4 Thickness_m 0.01 ArmorThickness_m 0.0025 Panels 2 FrontTaper_radians 0 BackTaper_radians 0 SurfaceFinish null
RadiatorModule 4x8 Amorphous Carbon Radiator (Light) UsesCustomName true Composition Amorphous Carbon PanelWidth_m 2 Height_m 8 Thickness_m 0.01 ArmorThickness_m 0.0025 Panels 2 FrontTaper_radians 0 BackTaper_radians 0 SurfaceFinish null
NuclearThermalRocketModule 5.27 km/s RP-1 Gimballed Nuclear Thermal Rocket UsesCustomName false ReactorCoreHeight_m 3.1 NuclearReactor Coolant RP-1 Moderator Graphite ModeratorMass_kg 0 Fuel U-235 Dioxide FuelMass_kg 500 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 400 NeutronReflector Amorphous Carbon ReflectorThickness_m 0.85 AverageNeutronFlux__m2_s 1e+020 ThermalRocket ChamberComposition Diamond ThroatRadius_m 0.1 ChamberWallThickness_m 0.1 ChamberContractionRatio 2.5 NozzleExpansionRatio 42 NozzleExpansionAngle_degrees 10 RegenerativeCooling_Percent 0 Injector Composition Boron PumpRadius_m 1 RotationalSpeed_RPM 530 Gimbal InnerRadius_m 1.5 ArmorComposition Diamond ArmorThickness_m 0.01 MomentumWheels Composition Boron RotationalSpeed_RPM 12500 GimbalAngle_degrees 30
CrewModule 100 Crew Module UsesCustomName false CrewCapacity 100 Decks 20 StructureMaterial Titanium ShellThickness_m 0.01
ThermoelectricFissionReactorModule 15.1 MW Thermoelectric Fission Reactor UsesCustomName true ReactorCoreDimensions_m 0.026 0.058 NuclearReactor Coolant Sodium Moderator Boron Nitride ModeratorMass_kg 0.03 Fuel U-235 Dioxide FuelMass_kg 0.271 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 0.175 NeutronReflector Diamond ReflectorThickness_m 1 AverageNeutronFlux__m2_s 1e+020 InnerTurbopump Composition Amorphous Carbon PumpRadius_m 0.25 RotationalSpeed_RPM 450 ThermocoupleInnerDimensions_m 0.5 0.85 Thermocouple PTypeComposition Osmium NTypeComposition Tungsten Length_m 0.001 ThermocoupleExitTemperature_K 2500 OuterCoolant Sodium OuterTurbopump Composition Amorphous Carbon PumpRadius_m 0.1 RotationalSpeed_RPM 600
CraftBlueprint Reusable Earth SSTO Modules 100 Crew Module 7 0 null 0 2.50 kt RP-1 Tank 7 -0.5 null 0 250 t RP-1 Tank 19 0.75 null 0 100 t RP-1 Tank 7 2.75 null 0 15.1 MW Thermoelectric Fission Reactor 1 217.34 null 0 5.00 m x 0 m Spacer 1 220.88 null 0 2x4 Amorphous Carbon Radiator (Light) 4 5.4618 15.1 MW Thermoelectric Fission Reactor 0 4x8 Amorphous Carbon Radiator (Light) 4 20.906 100 Crew Module 0 4x8 Amorphous Carbon Radiator (Light) 4 12.581 100 Crew Module 0 5.27 km/s RP-1 Gimballed Nuclear Thermal Rocket 4 0 null 0 4x8 Amorphous Carbon Radiator (Light) 4 29.301 100 Crew Module 0 100 t RP-1 Tank 19 1.25 null 0 25.0 t RP-1 Tank 7 3.75 null 0 Armor ArmorLayers Titanium 0.025 0 0 1 1 Silica Aerogel 0.05 0 0 1 1 Silicon Nitride 0.005 0 0 1 1
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Post by The Astronomer on May 10, 2017 15:30:07 GMT
...Acceleration of 2.34 g's sounds like overkill, but it's less than the space shuttle at liftoff (3 g's)...
The space shuttle acceleration at lift off is 1.5g, and went up to 3g when the engines cut...
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Post by Zerraspace on May 10, 2017 15:38:44 GMT
Point taken, but I don't think it breaks the logic of the vessel; the drives just don't mass enough for there to be any significant gains from losing one, and seeing as it can do 1.755 g's wet with one of the four broken 1.17 g wet with two broken, that provides massive redundancy, which you'll need for something doing this many flights.
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Post by ash19256 on May 10, 2017 21:00:55 GMT
Not to mention, with four engines, you can shut down two of them in flight when the g-load starts getting too high to reduce thrust beyond the engine's capability to throttle. For multiple flights, you could even alternate which pair of engines shut down to extend the life of the engines and ensure that they wear evenly.
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Post by randomletters on May 10, 2017 21:40:31 GMT
The 9.4 km/s delta-v required to get into orbit has already included the atmospheric drag.[/quote] My mistake then. nerd1000Unless you're using a modded defines file to give more layers for your crew modules 200 man modues are about 20% more weight efficient than 1000 man ones.
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Post by Argopeilacos on May 13, 2017 12:38:46 GMT
Revised submission: The light one is an improvement on my first submission, with fewer components, a heavier NTR and cost-optimized (i.e. boron everywhere!): It fits 202 passengers and 38 crew for 8.18 M¢ (34,083 ¢/seat), with 200t of cargo (40,900 ¢/t). Code:
NuclearThermalRocketModule XNTR-M-5.92-1160-U233 (Unshielded, Unarmored, 101kPa) UsesCustomName true ReactorCoreHeight_m 0.6 NuclearReactor Coolant Methane Moderator Diamond ModeratorMass_kg 0 Fuel U-233 Dioxide FuelMass_kg 50 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 6.9 NeutronReflector Pyrolytic Carbon ReflectorThickness_m 0 AverageNeutronFlux__m2_s 1.23e+020 ThermalRocket ChamberComposition Boron ThroatRadius_m 0.339 ChamberWallThickness_m 0.00488 ChamberContractionRatio 8 NozzleExpansionRatio 4.8 NozzleExpansionAngle_degrees 7.4 RegenerativeCooling_Percent 1 Injector Composition Magnesium PumpRadius_m 0.53 RotationalSpeed_RPM 575 Gimbal InnerRadius_m 0.76 ArmorComposition Silica Aerogel ArmorThickness_m 0.0001 MomentumWheels Composition Magnesium RotationalSpeed_RPM 4900 GimbalAngle_degrees 5
CrewModule Long 80 Crew Module UsesCustomName true CrewCapacity 80 Decks 27 StructureMaterial Polyethylene ShellThickness_m 0.01
CargoModule 200 t Cargo Bay Mass_kg 2e+005 AspectRatio 0.2 Shell Boron
ThermoelectricFissionReactorModule 25.0 kW LRR UsesCustomName true ReactorCoreDimensions_m 0.075 0.019 NuclearReactor Coolant Ethane Moderator Diamond ModeratorMass_kg 0 Fuel U-233 Dioxide FuelMass_kg 0.1 FuelEnrichment_Percent 0.05 ControlRodComposition Depleted Uranium Dioxide ControlRodMass_kg 0.1 NeutronReflector Diamond ReflectorThickness_m 0 AverageNeutronFlux__m2_s 8.8e+018 InnerTurbopump Composition Graphite PumpRadius_m 0.075 RotationalSpeed_RPM 100 ThermocoupleInnerDimensions_m 0.074 0.5 Thermocouple PTypeComposition Tungsten NTypeComposition Tantalum Length_m 0.001 ThermocoupleExitTemperature_K 2000 OuterCoolant Decane OuterTurbopump Composition Graphite PumpRadius_m 0.075 RotationalSpeed_RPM 14
RadiationShieldModule GTFO Light Li-6 RadShield UsesCustomName true Composition Lithium-6 Dimensions_m 4 0.01
RadiationShieldModule 5.2 m Diameter 0.5 cm Li-6 RadShield UsesCustomName true Composition Lithium-6 Dimensions_m 2.6 0.005
PropellantTankModule GTFO Heavy Methane Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 2e+006 HeightToRadiusRatio 6 AdditionalArmorThickness_m 0
PropellantTankModule = 250t Methane Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 2.5e+005 HeightToRadiusRatio 6 AdditionalArmorThickness_m 0
PropellantTankModule 480t Methane Drop Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 4.8e+005 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.17 ExplosiveBoltComposition Nitrocellulose
RadiatorModule 0.2x2 AC Radiator UsesCustomName true Composition Amorphous Carbon PanelWidth_m 0.2 Height_m 2 Thickness_m 0.06 ArmorThickness_m 0.004 Panels 1 FrontTaper_radians 0 BackTaper_radians 0 SurfaceFinish Diamond
RadiatorModule GTFO Light Boron Radiator UsesCustomName true Composition Boron PanelWidth_m 2 Height_m 15 Thickness_m 0.002 ArmorThickness_m 0.002 Panels 1 FrontTaper_radians 1.219 BackTaper_radians 0 SurfaceFinish Diamond
CraftBlueprint GTFO Light Modules XNTR-M-5.92-1160-U233 (Unshielded, Unarmored, 101kPa) 4 0 null 0 Long 80 Crew Module 3 20.974 null 0 200 t Cargo Bay 1 9.9869 null 0 25.0 kW LRR 1 110.79 null 0 GTFO Light Li-6 RadShield 1 4.4934 null 0 5.2 m Diameter 0.5 cm Li-6 RadShield 1 66.383 null 0 10.0 m x 0 m Spacer 1 111.56 null 0 GTFO Heavy Methane Tank (Boron) 1 15.48 null 0 = 250t Methane Tank (Boron) 1 21.466 null 0 480t Methane Drop Tank (Boron) 3 33.277 null 0 0.2x2 AC Radiator 2 130.68 25.0 kW LRR 1.57 GTFO Light Boron Radiator 3 17.008 Long 80 Crew Module 1.04 Armor ArmorLayers Amorphous Carbon 0.002 0 0 1 1
The heavy one is an attempt at economy of scale: This one fits 995 passengers and 55 crew for 28.8 M¢ (27,428 ¢/seat) but has no cargo capacity. Code:
NuclearThermalRocketModule XNTR-M-5.92-1160-U233 (Unshielded, Unarmored, 101kPa) UsesCustomName true ReactorCoreHeight_m 0.6 NuclearReactor Coolant Methane Moderator Diamond ModeratorMass_kg 0 Fuel U-233 Dioxide FuelMass_kg 50 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 6.9 NeutronReflector Pyrolytic Carbon ReflectorThickness_m 0 AverageNeutronFlux__m2_s 1.23e+020 ThermalRocket ChamberComposition Boron ThroatRadius_m 0.339 ChamberWallThickness_m 0.00488 ChamberContractionRatio 8 NozzleExpansionRatio 4.8 NozzleExpansionAngle_degrees 7.4 RegenerativeCooling_Percent 1 Injector Composition Magnesium PumpRadius_m 0.53 RotationalSpeed_RPM 575 Gimbal InnerRadius_m 0.76 ArmorComposition Silica Aerogel ArmorThickness_m 0.0001 MomentumWheels Composition Magnesium RotationalSpeed_RPM 4900 GimbalAngle_degrees 5
ThermoelectricFissionReactorModule 25.0 kW LRR UsesCustomName true ReactorCoreDimensions_m 0.075 0.019 NuclearReactor Coolant Ethane Moderator Diamond ModeratorMass_kg 0 Fuel U-233 Dioxide FuelMass_kg 0.1 FuelEnrichment_Percent 0.05 ControlRodComposition Depleted Uranium Dioxide ControlRodMass_kg 0.1 NeutronReflector Diamond ReflectorThickness_m 0 AverageNeutronFlux__m2_s 8.8e+018 InnerTurbopump Composition Graphite PumpRadius_m 0.075 RotationalSpeed_RPM 100 ThermocoupleInnerDimensions_m 0.074 0.5 Thermocouple PTypeComposition Tungsten NTypeComposition Tantalum Length_m 0.001 ThermocoupleExitTemperature_K 2000 OuterCoolant Decane OuterTurbopump Composition Graphite PumpRadius_m 0.075 RotationalSpeed_RPM 14
RadiationShieldModule GTFO Heavy Li-6 RadShield UsesCustomName true Composition Lithium-6 Dimensions_m 6 0.018
RadiationShieldModule 5.2 m Diameter 0.5 cm Li-6 RadShield UsesCustomName true Composition Lithium-6 Dimensions_m 2.6 0.005
PropellantTankModule = 250t Methane Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 2.5e+005 HeightToRadiusRatio 6 AdditionalArmorThickness_m 0
PropellantTankModule GTFO Heavy Methane Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 2e+006 HeightToRadiusRatio 6 AdditionalArmorThickness_m 0
RadiatorModule 0.2x2 AC Radiator UsesCustomName true Composition Amorphous Carbon PanelWidth_m 0.2 Height_m 2 Thickness_m 0.06 ArmorThickness_m 0.004 Panels 1 FrontTaper_radians 0 BackTaper_radians 0 SurfaceFinish Diamond
CrewModule Long 150 Crew Module UsesCustomName true CrewCapacity 150 Decks 50 StructureMaterial Polyethylene ShellThickness_m 0.01
PropellantTankModule 2.4kt Methane Drop Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 2.4e+006 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.3 ExplosiveBoltComposition Nitrocellulose
RadiatorModule GTFO Heavy Boron Radiator UsesCustomName true Composition Boron PanelWidth_m 3.2 Height_m 32 Thickness_m 0.002 ArmorThickness_m 0.002 Panels 1 FrontTaper_radians 1.216 BackTaper_radians 0 SurfaceFinish Diamond
PropellantTankModule 2.4kt Methane Drop Tank (Boron) UsesCustomName true Propellant Methane StructureComposition Boron ReactionMass_kg 2.4e+006 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.3 ExplosiveBoltComposition Nitrocellulose
CraftBlueprint GTFO Heavy Modules XNTR-M-5.92-1160-U233 (Unshielded, Unarmored, 101kPa) 11 0 null 0 25.0 kW LRR 2 110.79 null 0 GTFO Heavy Li-6 RadShield 1 9.987 null 0 5.2 m Diameter 0.5 cm Li-6 RadShield 1 66.128 null 0 10.0 m x 0 m Spacer 1 111.56 null 0 = 250t Methane Tank (Boron) 1 21.466 null 0 GTFO Heavy Methane Tank (Boron) 1 21.343 null 0 0.2x2 AC Radiator 2 190.67 25.0 kW LRR 0.79 Long 150 Crew Module 7 21.192 null 0 2.4kt Methane Drop Tank (Boron) 2 52.705 null 1.57 GTFO Heavy Boron Radiator 4 29.496 Long 150 Crew Module 0.78 2.4kt Methane Drop Tank (Boron) 2 53.705 null 0 Armor ArmorLayers Amorphous Carbon 0.002 0 0 1 1
Both use this NTR:
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Post by deskjetser on May 13, 2017 17:19:02 GMT
My half witted attempt at this, the only way I know how; The Boron Cucumber1,580,000,000¢ of totally not wasted tax payer funds, to send ~21,000 people into LEO for the low-ish cost of 75,500¢ per seat, including 95kg of cargo per passenger! This behemoth was dreamt up by a team of engineers huffing paint thinner on a Saturday afternoon while wondering what to do with a scrap NTR they just had lying around. Yes, that's right, this monstrosity only has one engine!
Okay so on a serious note; It's not going to win any prizes, here especially; Well, maybe the prize for best bad idea. Here are some additional pictures and information in case Pttg wants to add it to the list. It's kind of large...2kt of cargo, 95kg per passenger.The cut down Beelzebub that powers it, with 102kPa at the nozzle.
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Post by apophys on May 14, 2017 5:52:29 GMT
Here's my version: Terra Spore 1800.txt (6.7 KB) From scratch, a seat is 33,972 c/passenger. (1722 passengers) It is fully reusable (you don't need to actually drop the droptanks). Propellant alone is 24.38 Mc, resulting in a crazy low seat cost of 14,158 c/passenger. (1722 passengers) On NTR thrust, it gets 10.4 km/s at full load. It can fulfill its mission with 2 broken engines and 2 ruptured prop tanks: 10 km/s (still more than enough for a powered landing and reuse, according to Zerraspace above). A 1 GW MPD is included for orbital maneuvering (leftover propellant after reaching orbit might actually be enough to get to Mars in one go...) If the ship is refueled in Earth's orbit, it can reach any rocky surface in the solar system, and then come back (except Venus, but nobody wants to go to the surface of Venus). Lasers are included to sweep space debris. Much better than risking impact or burning propellant to dodge. Effective to 1 Mm, and armored with 1cm boron like the rest of the ship. A boron nitride coating is included as a chemical-resistant surface (It's untouchable to atmospheric nitrogen at least. ).
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Post by samchiu2000 on May 14, 2017 6:35:33 GMT
Here's my version: From scratch, a seat is 33,972 c/passenger. (1722 passengers) It is fully reusable (you don't need to actually drop the droptanks). Propellant alone is 24.38 Mc, resulting in a crazy low seat cost of 14,158 c/passenger. (1722 passengers) On NTR thrust, it gets 10.4 km/s at full load. It can fulfill its mission with 2 broken engines and 2 ruptured prop tanks: 10 km/s (still more than enough for a powered landing and reuse, according to Zerraspace above). A 1 GW MPD is included for orbital maneuvering (leftover propellant after reaching orbit might actually be enough to get to Mars in one go...) If the ship is refueled in Earth's orbit, it can reach any rocky surface in the solar system, and then come back (except Venus, but nobody wants to go to the surface of Venus). Lasers are included to sweep space debris. Much better than risking impact or burning propellant to dodge. Effective to 1 Mm, and armored with 1cm boron like the rest of the ship. A boron nitride coating is included as a chemical-resistant surface (It's untouchable to atmospheric nitrogen at least. ). So a armed, interplanetary liner that can take off from earth and go to Mars without a single refueling with cost of <34000 per seat? IMPRESSIVE!!!
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Post by The Astronomer on May 14, 2017 10:19:14 GMT
Here's my version: From scratch, a seat is 33,972 c/passenger. (1722 passengers) It is fully reusable (you don't need to actually drop the droptanks). Propellant alone is 24.38 Mc, resulting in a crazy low seat cost of 14,158 c/passenger. (1722 passengers) On NTR thrust, it gets 10.4 km/s at full load. It can fulfill its mission with 2 broken engines and 2 ruptured prop tanks: 10 km/s (still more than enough for a powered landing and reuse, according to Zerraspace above). A 1 GW MPD is included for orbital maneuvering (leftover propellant after reaching orbit might actually be enough to get to Mars in one go...) If the ship is refueled in Earth's orbit, it can reach any rocky surface in the solar system, and then come back (except Venus, but nobody wants to go to the surface of Venus). Lasers are included to sweep space debris. Much better than risking impact or burning propellant to dodge. Effective to 1 Mm, and armored with 1cm boron like the rest of the ship. A boron nitride coating is included as a chemical-resistant surface (It's untouchable to atmospheric nitrogen at least. ). This is the best ship I've ever seen.
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Post by hyno111 on May 15, 2017 6:46:35 GMT
"I..I think that may not w-" "But we can use those tanks in storage! They are purchased at an discounted price! What are you waiting for!?" Nearly everything is stock, except the engine and 400t Oxygen Drop Tank.
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Post by Zerraspace on May 16, 2017 0:36:36 GMT
apophys sure knows how to please a crowd. I'd be a bit concerned about aerodynamics but in terms of performance and capabilities it's exactly where I want to be. So after submitting the Reusable SSTO, I thought about making a more dedicated attempt, and so fished around the editor examining material prices, specifically propellant, since that seemed to make up a good fraction of the cost of the vessel. The material-cost relationship baffles me (Gasping for Fumes states that it's largely based on solar abundance and ease of extraction, but neither of those would explain how hydrogen is more expensive than hydrogen deuteride or helium, and certainly not how it's more expensive than xenon; similarly, how is neon cheaper than ubiquitous water?), but it did get me to thinking that instead, I could go further with my initial assumption - of creating a ship using solely commonplace conventional materials - by using an even more basic propellant, one that's essentially omnipresent on Earth and requires almost no processing: water. Now right off the bat, you could guess that the much lower exhaust velocity would result in a much higher mass ratio and an overall inferior craft. Recreating the ship with nearly the exact same composition and capabilities resulted in a 237 Mc vessel for 635 passengers, translating to a staggering 373228 c/passenger. While it is still completely reusable, filling up on 96.75 kilotons is not cheap, even of 1.48 c/kg water: that would cost 143.19 Mc per launch, amounting to 225496 c/passenger. However, I think the applicability would make this ship more useful than its predecessor, since refueling would require little more than bringing a pipe and pump to a nearby river. Sure, said river on the dying Earth might not be clean enough to use, but filters have got to be cheaper than setting up a factory to make new hydrocarbons. Using a completely subjective measure outside the game experience, bulk distilled water can be bought for about $1/gallon (so 0.25 $/kg) and the average price for water overall in the US is $1.5/ton; by those metrics, cost per passenger would be $38500 and $232 (!) per passenger, if propellant were the only concern. Now, realistically, we'd also have to account for maintenance and crew pay, plus profit margins, and there's a good chance clean water is becoming a commodity on dying Earth so prices are going to be much higher... but it's a place to start. Here are the images: Here's the ship next to the original for comparison. For purposes of this challenge, it's worse in every way except delta-v (by only the slimmest margin) and possibly part redundancy - it's much larger, much heavier and more expensive for slightly less capacity (maintenance on this thing must be a nightmare), with less wet acceleration to boot and thinner walls relative to its weight (for how thick they are, I don't think they'd hold up too well for real takeoff; if I had to guess, the tankage and internal struts must be doing their work). Not that I was really aiming to pass that at this point... The culprit is the new mass ratio, a staggering 16.5, requiring much more tankage and covering to compensate, and providing a whole lot of mass to be moved. 103 kilotons, that amounts to 147142 kg to get a person to orbit. That sounds terrible, but if you figure the 2000 ton space shuttle assembly never went up with more than 8 people at a time, it's still an improvement on modern technology. Amusingly, the dry mass is not actually all that much higher than for the original SSTO, which coupled with the significantly larger cross-section, means this ship would have an easier time aerobraking during descent. It's certainly got ample thrust for powered landing! Here's a look at the insides: this one required many more layers of tanks in order to keep a trim profile, though this is far from how good it could be. An earlier version using 19x 20 crew parts was the same width as the Reusable SSTO and very nearly cylindrical except at the top, but the crew sunk just maintaining the crew modules themselves convinced me to return to the prior arrangement. And the codes, of course. The "cheap" 100 crew compartment is the same as for the last one; it's called that because I experimented with changing it to magnesium, cutting out much mass and a bit of the cost, but I figured titanium is stronger and hence safer, plus a more conventional material in the spirit of my self-imposed challenge:
RadiatorModule 1x4 Amorphous Carbon Radiator (Light) UsesCustomName true Composition Amorphous Carbon PanelWidth_m 1 Height_m 4 Thickness_m 0.01 ArmorThickness_m 0.0025 Panels 1 FrontTaper_radians 0 BackTaper_radians 0 SurfaceFinish null
RadiatorModule 8x8 Amorphous Carbon Radiator (Light) UsesCustomName true Composition Amorphous Carbon PanelWidth_m 2 Height_m 8 Thickness_m 0.01 ArmorThickness_m 0.0025 Panels 4 FrontTaper_radians 0 BackTaper_radians 0 SurfaceFinish null
PropellantTankModule 100 t Water Tank UsesCustomName false Propellant Water StructureComposition Boron ReactionMass_kg 1e+005 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 2.50 kt Water Tank 2 UsesCustomName false Propellant Water StructureComposition Boron ReactionMass_kg 2.5e+006 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 5.00 kt Water Tank 2 UsesCustomName false Propellant Water StructureComposition Boron ReactionMass_kg 5e+006 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 5.00 kt Water Tank 3 UsesCustomName false Propellant Water StructureComposition Boron ReactionMass_kg 5e+006 HeightToRadiusRatio 5 AdditionalArmorThickness_m 0
CrewModule 100 Crew Module (Cheap) UsesCustomName true CrewCapacity 100 Decks 20 StructureMaterial Titanium ShellThickness_m 0.01
ThermoelectricFissionReactorModule 15.1 MW Thermoelectric Fission Reactor UsesCustomName true ReactorCoreDimensions_m 0.026 0.058 NuclearReactor Coolant Sodium Moderator Boron Nitride ModeratorMass_kg 0.03 Fuel U-235 Dioxide FuelMass_kg 0.271 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 0.175 NeutronReflector Diamond ReflectorThickness_m 1 AverageNeutronFlux__m2_s 1e+020 InnerTurbopump Composition Amorphous Carbon PumpRadius_m 0.25 RotationalSpeed_RPM 450 ThermocoupleInnerDimensions_m 0.5 0.85 Thermocouple PTypeComposition Osmium NTypeComposition Tungsten Length_m 0.001 ThermocoupleExitTemperature_K 2500 OuterCoolant Sodium OuterTurbopump Composition Amorphous Carbon PumpRadius_m 0.1 RotationalSpeed_RPM 600
NuclearThermalRocketModule 3.64 km/s Water Gimballed Nuclear Thermal Rocket 2 UsesCustomName false ReactorCoreHeight_m 0.66 NuclearReactor Coolant Water Moderator Graphite ModeratorMass_kg 0 Fuel U-235 Dioxide FuelMass_kg 360 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 280 NeutronReflector Boron Nitride ReflectorThickness_m 0.6 AverageNeutronFlux__m2_s 2.1e+020 ThermalRocket ChamberComposition Diamond ThroatRadius_m 0.18 ChamberWallThickness_m 0.089 ChamberContractionRatio 2.5 NozzleExpansionRatio 50 NozzleExpansionAngle_degrees 15 RegenerativeCooling_Percent 0 Injector Composition Amorphous Carbon PumpRadius_m 0.77 RotationalSpeed_RPM 605 Gimbal InnerRadius_m 1.11 ArmorComposition Amorphous Carbon ArmorThickness_m 0.05 MomentumWheels Composition Boron RotationalSpeed_RPM 18000 GimbalAngle_degrees 30
CraftBlueprint Aqua Ascendia Modules 3.64 km/s Water Gimballed Nuclear Thermal Rocket 2 19 0 null 0 5.00 kt Water Tank 3 7 7.2049 null 0 5.00 kt Water Tank 2 7 56.488 null 0 1.000 kt Water Tank 2 7 58.488 null 0 100 t Water Tank 19 59.494 null 0 100 t Water Tank 7 60.865 null 0 15.1 MW Thermoelectric Fission Reactor 1 283.91 null 0 10.0 m x 0 m Spacer 1 287.38 null 0 1x4 Amorphous Carbon Radiator (Light) 3 38.259 15.1 MW Thermoelectric Fission Reactor 0 1x4 Amorphous Carbon Radiator (Light) 3 42.962 15.1 MW Thermoelectric Fission Reactor 0 1x4 Amorphous Carbon Radiator (Light) 3 47.606 15.1 MW Thermoelectric Fission Reactor 0 1x4 Amorphous Carbon Radiator (Light) 3 52.309 15.1 MW Thermoelectric Fission Reactor 0 100 Crew Module (Cheap) 7 57.988 null 0 2.50 kt Water Tank 2 7 57.488 null 0 8x8 Amorphous Carbon Radiator (Light) 3 23.044 100 Crew Module (Cheap) 0 8x8 Amorphous Carbon Radiator (Light) 3 14.099 100 Crew Module (Cheap) 0 8x8 Amorphous Carbon Radiator (Light) 3 31.72 100 Crew Module (Cheap) 0 Armor ArmorLayers Titanium 0.025 0 0 1 1 Silica Aerogel 0.05 0 0 1 1 Silicon Nitride 0.0005 0 0 1 1
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