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Everything posted by wafflemoder

  1. If basically any part of the pod fails, it doesn't matter if the parachute works or not, you will die before you can come down, if not on the way up. And you can absolutely pin-point what part in the pod is responsible for the failure, that's part of what telemetry is for. Even for a dumb chasis (which a pod very much is not) it is still larger and hence requires more material and a larger workforce to construct, and so should cost more.
  2. Yeah. As much I would like a total overhaul of the entire game balance, that is a lot of work. Part cost should be one of the easiest to rebalance since its basically self contained, which is why I focused on it.
  3. Its not the actual cost of the vehicles, and this is arguably just to not hinder new career mode players. The prices of parts are weird in relation to each other. That is true, but that also applies to every other part in KSP, not just engines. Relative pricing should still hold if all parts are manufactured at equal rates. The engines in cars and aircraft are good examples of this in action, as both are very much mass produced and engines still make up a large fraction of the total cost. The actual material costs should be minimal in comparison to the manufacturing process.
  4. Part cost isn't something that is normally brought up with regards to balance or realism. Part cost is only important in Career, and even in career, it isn't really that big of a concern, so its understandable why it isn't brought up that much. Still, it is very much a part of the game that should be looked at, as there is a lot that can be improved upon. Before diving into KSP costs, it's good to look at the costs of components in real launch vehicles. Now, pricing launch vehicles is surprisingly difficult, but fortunately just relative costs for parts is all we need for now. For the pl
  5. Two things I noticed about the FX-2 and FX-3 fusion reactors that may not be the intended behavior: 1) D-He3 mode consumes 10 times as much fuel as D-D mode, but only puts out twice as much power. 2) Assuming I did the math correct, the specific energy of the D-D and D-He3 fuel cycles are less than that of enriched uranium in the NFE reactors. For this, I used a two part formula. One for finding the energy per unit of fuel (generated power/ fuel use), and the other for converting in game units to kg (mass/units) - The NFE reactors give fuel specific energies between approximatel
  6. A relevant method for reducing thrust without throttling down http://www.projectrho.com/public_html/rocket/realdesigns.php#id--Basic_Solid_Core_NTR--Cascade_Vanes This design was considered for use in solid core nuclear rockets, but some magnetic equivalent might be feasible for more energenic propulsion systems.
  7. You can get the same effect by using the moon itself as a gravity tractor for earth. This simplifies the design, and saves both the tides and venus. A large solar laser could be used to push the moon, or even the earth itself, further simplifying things and allowing for much faster timescales.
  8. A relevant video by Isaac Arthur on the logistics of moving planets Hope this helps.
  9. Well yes, but actually no. Like all things, it's complicated. So first off, my one and only defence what you were watching. We can do a pretty good job correcting for observation bias, as its something scientists know about going into things, and they have to work around it on a regular basis. When correcting for the planets we know we can't observe, and using the planets we can see to gauge their likelihood, we still find that most exoplanets are larger than Earth. That being said, there are still a lot of assumptions and misconceptions that can be unpacked here. Most of the ex
  10. Fusion rockets are in fact easier to achieve than fusion power. This is because a fusion power plant needs to break even, making more energy than it uses. On the other hand, while a self sustaining fusion rocket would be very good to have, especially one that could be tapped for power, they aren't necessary. There are some designs for fusion rockets that use a fission reactor to provide power for their operation.
  11. Well yes, but actually no. You could, but it wouldn't be an ion thruster anymore. Ion thrusters specifically use electricity to energize their propellant, rather than through heating by use of fusion or antimatter. In principle, you could use an ion engine powered by a fusion reactor and antimatter fuel cell, but it would be better in almost every circumstance to just heat a propellant through fusion or antimatter instead. Thermal propulsion would be lighter, simpler, and would give higher performance. The only downside is that these thermal systems wouldn't be able to change throttl
  12. Realistically, any form of space elevator, space tower/space fountain, launch loop, or orbital ring will be more environmentally friendly in the long run as no propellants are needed, and all components are multi use. But, its nonsensical to say that any of these methods are "propellants". The original question was about the most eco-friendly propellant, not the most eco-friendly surface to orbit transportation system, or even the most eco-friendly rocket design. These are all complex and intertwined questions for sure, and the question is framed in such a way that some pollution will be
  13. First off, if a civilization's goal is to preserve the environment, monetary cost will be a non-issue. And biogas isn't even cheaper than minning, thats why we still mine. Secondly, Biogas is biologically produced methane and methanol, as are all fossil fuels. What makes biofuels "cleaner" than petroleum fuels isn't that they're a different chemical, its that biofuels are made from the carbon already in our atmosphere, rather than carbon which has been stored in the ground for hundreds of millions of years. Burning biofuels simply returns the CO2 that was used to make it back into the atm
  14. Which is why I suggested running it off of a biogas powerplant rather than natural gas. Also its abilty to sequester carbon in elemental can reduce, or even give it a negative carbon footprint. Interestingly, the Kværner process is very similar (and possibly identical) to what happens in a nuclear rocket when you use methane as a propellant, only the carbon soot builds up in the engine, which can cause blockages or affect the neutron moderation in the reactor, and isn't desirable in that situation.
  15. Introducing the Kværner process, which converts natural gas or biogas directly into nearly pure carbon and hydrogen. A carbon neutral biogas powered and biogas fueled system could be implemented relatively easily by any eco-conscious future civilization if so inclined. As a bonus, the carbon could be used in ceramics, composites, or high strength carbon allotropes like carbon nanotubes and graphene. So technically it would be a carbon sink, rather than simply carbon neutral. Much more broadly speaking, an eco-conscious space fairing future civilization could migrate all power, manufacturi
  16. The best solution I could see is having space-based FTL capable superships with a fleet of surface-to-orbit shuttles and a few interplanetary shuttles. These supership would have to be constructed in orbit or on a small moon or asteroid, mass hundreds of kilotons to over a gigaton, and be up to several kilometers long. This lines up well with what you were originally looking for in terms of size (or many times larger) but be limited to space. They would be able to land on the smallest rounded objects like Ceres, but anything larger would be a one way trip down and cause significant damage
  17. Can't polute an environment that isn't there anymore Forehead On a more serious note, you need to consider not just the propellant itself, but what the exhaust products will be, how they can react to the air, and how the air responds to the intense localized heating of an engine. Regardless of the propellant, if it's hot enough, some of the surrounding air will be converted into the nitrogen oxides NO2, NO, and N2O, which are all powerful greenhouse gasses (N2O is ~15x worse than methane and 300 times worse than CO2) and are toxic. As these are also created by natural biological and
  18. A ship like that would probably be able to refuel from water ice and hydrates. This would allow it refuel basically anywhere. The only locations in our solar system such a vessel wouldn't be able to refuel from would be Venus, Jupiter, Saturn, Uranus, Neptune, and possibly Io. Nearly all outer solar system bodies (with the exception of Io, and possibly some minor bodies) have thick crusts of icy material. Main belt objects like Ceres and Vesta have hydrate minerals at the surface, where water can be cooked out of them fairly easily. Mars has considerable amounts of ice under much of its surfac
  19. Yeah, antimatter is kind of insane, and thats with using less efficient water as a propellant. This craft could probably only get 100t payloads off of worlds less than 2 Earth masses with thin earthlike atmospheres, which should cover most "Earthlike" planets. On smaller worlds however, its payload capacity skyrockets. Quick table of parameters for the same vehicle for different world sizes. (limiting vehicle parameter in bold) World Mars Ganymede Pluto Ceres Required dV (km/s) 4
  20. No worries there. Here's a "basic" rundown of what a water propelled AM Gas Core SSTO could look like. My assumptions: 16000 m/s of dV. Upright landing, change height to length if sideways landing is desired (doesn't make any real difference) 8 meter diameter rocket, height determined by tankage volume. Additional 8 meters in height from engines, and 25 meters in height from payload bay. 100t payload + 10t for misc structural and avionics. Water: 0.8 kg/L in tankage. Tankage mass is 5% the propellant mass. (95.3% propellant) Antiprotons: 0.01 kg/L in t
  21. In terms of shuttle craft, there should be a lot of options available (I'm assuming shuttles are non-FTL craft primarily for ferrying small crews or payloads to and from planets and moons with various masses and atmospheres) With how large your ships are, you could probably get away with having a few types of shuttles for various purposes and/or of various sizes. If the technology is available, you could have smart ships that reconfigure themselves for a specific task. Shuttle craft probably wouldn't be needed (but nice to have) for more developed worlds with extensive orbital infrastruct
  22. As none of them are chemical based, pretty much any fluid propellant can be used, with the exceptions of nuclear saltwater rockets and fusion augmented antimatter. Internal plumbing would have to be tailored to a certain propellant though (no jury rigging an H2O fueled craft to use O2, or at least not easily). The propellant used would affect the ISP and engine power with higher molar mass particles generally giving lower thrust and ISP. Some propellant processing will be required though, to remove any materials that could cause blockages in the plumbing where temperatures aren't 5000+ Ke
  23. It is quite probable that there are additional planets in the system. Here's my somewhat lengthy, but hopefully comprehensive summary on what types of worlds could be where in the system based on our current understanding of planetary science. For reference, these are the two types of planetary orbits in multiplanetary systems. S-type orbits go around a singular star, and P-type orbits go around multiple stars. There are four main regions where planets could reside in the Alpha Cen. + Proxima Cen. ternary system: S-type orbits around Proxima (C), S-type orbits around A, S-type orbits
  24. Now that have a slightly better handle on what your aiming for, here's a shortlist of what might work in your setting for planetary operations, and my best guess of performance and what they might look like. The Nuclear (Fission) Options: Liquid Core Fission Rocket (Open Cycle): Very good TWR, but lower ISP. Liquid fissiles mix with and heat hydrogen propellant. Most fissiles are kept within the reactor, but some can escape, possibly bad for occupied worlds. ISP of 1000-2000s, engine TWR of 8~50. Bright translucent white exhaust. No residual smoke or steam trail. Gas Core Fiss
  25. Oh yeah, that completely slipped my mind . Still beam cores might run into in efficiency issues with energy conversion with less reaction mass that can absorb the gamma (another reason why AM thermal is pretty good). AM thermal is a really good propulsion system, especially where high TWR is required and when antimatter is hard to come by. Just figured with the large amounts proposed in the OP that you might as well use it (that amount would also be ideal for a plasma core). Speaking of, just some math on the power requirements to produce 1 ton of antimatter every two months at various te
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