RadHazard

I apologize for coming off as lecturing. I did see where you mentioned that increased mass results in less ÃŽâ€v. It seems I misunderstood when you mentioned that you can save ÃŽâ€v with higher thrust values. I had assumed that you had confused an increase of burn time with an increase in ÃŽâ€v required, but after re-reading it I'm guessing you were talking about the ÃŽâ€v savings you get by reducing the amount of time you spend burning far from the node.

I'm back. I've been caught up with college work for the past month, but I figured I'd finally take a crack at some mixed integer linear programming. I'm planning on using Apache Commons Math for the matrix operations and implementing a simple cutting-plane algorithm. I'm hoping performance won't be too much of an issue since the number of variables I'm working with should be small. I'd like modify the solver to account for solar panels/RTGs at some point as well, but I think I'll try and get the basic fuel-tank solver working first before I try anything too crazy.

I partially agree, although I have managed a 2-kick burn to Jool using a ship that had a combined burn time of 11 minutes. However, unless I misunderstood, he wasn't talking about the difficulty of hitting a transfer window with a low-thrust craft. He was saying that higher-thrust craft needs to expend significantly less ÃŽâ€v to make the same transfer, which is untrue.

When 0.22 came out I tried to start using standardized launchers via the subassembly system, but I eventually gave up on that when I ended up revising my launchers after every new tech tree node. It wasn't hard for me to create a custom launcher for scratch most of the time anyway. However, I started revisiting that when I started needing a heavy-lift launcher, which was tougher for me to design from scratch. The only standardized Launcher I've made so far is the what I've named the Violetstone Heavy. The name comes from the redstone rocket family, which launched the first US satellite, and extrapolated up the electromagnetic spectrum. Here it is lifting a test payload (roughly 40.6 t) into a 70 km x 70 km orbit. It could probably lift a bit more since it had a bit of spare fuel left after I reached orbit, but I haven't pushed it to it's limit yet.

I had just started my career mode, and I had finally conquered LKO. My next goal was to send a probe to the Mun to do a flyby in preparation for a following manned flyby. This was back before I had unlocked solar panels, so I was still relying on battery power for my probes. Unfortunately for me, I had forgotten that little fact as I gleefully transmitted science home right up until I ran out of power. The probe ended up slingshotting around the Mun and into a Kerbol orbit. 5 years and 79 days later, it's still there, in fact. I thought about sending a mission to rendezvous with it at some point, but I have yet to get to that. Of course, I've neglected to rescue Jeb from the Mun's surface for the past 5 years as well, so that's probably not surprising.

Not quite. ÃŽâ€v is independent of burn time (assuming you discount factors such as inefficiencies due to burning during less optimal times during your orbit, which are non-trivial, but can be reduced by using multiple 'kicks' rather than one long one). If you want to change your orbit to a specific orbit for a transfer, you need to have a specific amount of velocity. The change in velocity you need to achieve at the burn point is known as required ÃŽâ€v. This is number is independent of the mass of a craft, and is derived only from it's current orbit and the orbit you want to achieve. This is how the ÃŽâ€v maps work. It takes (roughly) 2000 m/s to reach Jool, regardless of whether you are flying a 2 ton probe or a 200 ton colony ship. You are correct in saying increased mass decreases your available ÃŽâ€v. However, increasing thrust while keeping ISP constant (e.g. by adding more engines) will never increase your available ÃŽâ€v, even if you had zero-mass engines available. ISP is, quite simply, a measure of how much ÃŽâ€v you can get out of a given amount of fuel. To make it clear why this is, imagine you have a spaceship that consists of nothing but fuel tanks and two identical, weightless engines. If you were to run both engines, you would get 2X kN of thrust, where X is one engine's worth of thrust. If you were to shut off one of the engines, you would have only X thrust, meaning it would take twice as long to complete a burn. However, since you are only running one engine instead of two, you consume only half as much fuel in a given period of time, say 1 second, as you would with both engines running. At the end of the burn, both factors cancel out completely, meaning you have burned the exact same amount of fuel. This is consistent with basic physics, as you have hurled the same amount of fuel backwards at the same speed (albeit over a longer time period), regardless of the number of engines. Thus, the total momentum change of your rocket is equal. I'd also like to point out that the program in my sig uses the same calculations as what capi3101 is posting. You can play around with it using different number to verify the results posted (although you'd have to do it backwards, starting with a minimum TWR and ÃŽâ€v). The results are quite significant. For example, for a 5 ton payload, in order to achieve a ÃŽâ€v of 4000 and a (Kerbin-surface-relative) TWR of 1 when full, you'd need 4 LV-Ns and 9.29 tons of fuel, for a total mass of 23.29 tons. That same 5 ton payload with 4000 ÃŽâ€v but a relaxed Kerbin-surface-relative TWR of 0.5 requires only 1 LV-N and 4.81 tons of fuel, and has a total mass of 12.06 tons. The reason 1/4 the number of engines provides 1/2 the thrust is because of the tyranny of rocketry: You need more fuel to carry the increased engine mass, which needs more engines to get thrust needed for the same TWR, which needs more fuel... etc. Also note that Kerbin-surface-relative TWR (KSRTWR?) is simply an alternative way to represent a given level of acceleration a ship is capable of, since Kerbin surface gravity will always remain at 9.81m/s2 regardless of where you go in the universe. A more logical expression would be the Thrust-to-Mass ratio, where a TMR of 1 would represent the ability to accelerate at 1 m/s per second (1m/s2), but I figured most players would have an intuitive feel for how "thrusty" a ship with ~1-2 KSRTWR feels in space, since most early ships they would design would have about that much thrust.

Yeah, all the solar panels except the OX-STAT have had their solar curve tweaked.

To power a plasma engine with the same level of thrust that an upgraded 1.25m reactor/generator combo gives (which is a piddling 0.9 kN on liquid fuel), you'd need 480 tons of solar panels (using the OX-STAT panels, the most mass efficient of them, and assuming you're in Kerbin orbit). It's really not practical with anything other than microwave beamed solar satellites, which absolutely are possible in the current version. Other options in the current version are using a docked science lab to reprocess the fuel (vastly increases the lifetime of the reactor, but it will still run out eventually), or using antimatter reactors instead of nuclear (which requires high-level research). The next version is going to implement an automated reprocessing part, and will allow you to refuel reactors completely using new UF4 (reactors will run off of UF4 in the update) tanks.

Another feature I'd like is a "Preview mode" in the Tracking Center that lets you adjust the clock as you see fit. That way, you could plan out an interplanetary journey, say, 3 months ahead of time, and then set a reminder that'll pop up when the launch window comes up. A stock precise node editor like one of the 3 mods that currently exist wouldn't be a bad idea either.

I'd personally like both KAC's alarm clock feature and a Node Autopilot to be part of the stock game. I know most people are averse to autopilots, but I figure most of the challenge of setting up a transfer is getting the node right. Once you've got that, it's just a matter of keeping your ship straight (which SAS is usually capable of) and turning your engine off when you're done. It'd certainly help make those long burns less tedious.

I'm having a minor bug with the TWR limiter for thermal engines. The limiter works just fine and scales thrust to the proper limit, but it seems to be running the reactor as if the engine were using full power. Some screenshots: I would have had more but I was in the middle of a transfer burn when I noticed and I didn't want to screw it up.

It really is a matter of what you consider an acceptable level of thrust ratio vs how much dV you need. <shamelessplug> The design program in my sig can be pretty useful for figuring out the best design for your ships. </shamelessplug>

Correct, the inline advanced stabilizer is completely useless. You should just use the regular 1.25m reaction wheel any time you want extra torque, unless you care more about aesthetics than weight. It's still in-game simply for backwards comparability with older ships.

I forgot parachutes on my manned Joolean ship. It had done low space flybys of 3 Tylo, Vall, Laythe, and Jool with both Mystery Goo and Material Labs, plus it had three kerbals on it, so I wanted to return it to Kerbin in one piece. I attempted about a dozen powered landings on Kerbin (I was using the DT Vista from KSP Interstellar, so it had >1 TWR) before I finally managed to land it in the ocean without bits falling off and exploding. It was pretty intense, especially since it didn't have very strong torque so I had to be extremely careful about not accidentally tipping to the side. As a side note, I'm absolutely sure there were no adverse environmental effects from running an un-shielded nuclear inertial fusion engine in the atmosphere of a populated planet. None at all.

KSP Interstellar has a really nice implementation of magnetospheres, and version 0.8 looks like it'll add radiation as well. I can't imagine most people would mind the science portion of it being implemented into stock, but I don't know if everyone would be happy if they added radiation effects.

That's pretty neat. Is there a way to manually shut the reactor off in case you want to top off the fuel before an interplanetary mission or something?

I'm not sure if this is a bug or just strange behavior, but I built a DT Vista-powered science vessel and launched it to Jool. I had lithium tanks on board and during the flight to Jool I converted it to tritium until my tanks were full. After the tritium tanks were filled up, I went to turn off tritium breeding, but noticed the rate said 0.00kg/day, or whatever the unit was, so I just left it on. However, when I resumed time warping, it continued to consume lithium, although at an apparently slower rate. I remembered that tritium was radioactive and I thought that it might be decaying, but when I shut off the tritium breeding, both my lithium and tritium supplies stayed constant. Is tritium supposed to decay in-game? And if not, is tritium breeding supposed to continue to consume lithium even after your tanks are full? It's not a big deal since I can just micromanage my lithium supplies (I didn't even need the extra tritium for my mission, it turned out), but I figured it might be worth looking at.

I'm not sure if the numbers are right or not on the tables, but I can see how this is possible. The thrust each engine provides is based on the power the reactor provides and the reactor temperature, since Fractal wants the engines to obey conservation of energy. The thrust may be lower, but with the much higher Isp, they do still provide higher total delta V.

If you want to sync two or more satellite or station orbits so they stay roughly the same distance apart, it's easier to tweak the duration of each orbit than it is to make them perfect circles. You'll need a mod that displays more orbital info for that though.

My Jeb, or rather a clone since the original died in a fiery crash a long time ago, is currently stranded on the Mun for the third time as his lander once again didn't have enough fuel to lift both him and the science equipment back to Kerbin. He's been there for about a two and a half years now since I haven't bothered to send a rescue mission in between my Jool mission, my Eve mission, my second Jool mission, my second Eve mission, and a quick jaunt to the Mun and back by Bill (His ship had enough fuel to come back!).

Do you have any radiators? Generators need one to function, and reactors won't run for long without one.

More TWR means less drag losses when you launch, but it's partially dependent on your launch profile. I believe MechJeb has an in-flight readout that tells you how much dV you've lost from drag since you've launched, but I don't know if Engineer has the same thing. I'm not sure if there's an easy way to calculate this beforehand.

This, unfortunately, is the reason why we're still running coal and gas as our primary power sources. I agree, and I sincerely hope we decide to give increase the penalties for carbon emissions and other pollution sometime soon. The best way to develop any kind of clean alternative is to make the dirty one uneconomical.

While a world powered by renewable energy would be a wonderful thing, I don't know how possible it is. Most renewables are either heavily location dependent (geothermal, hydro, wind somewhat), erratic (solar, wind again), or have a low energy density (solar, meaning they work better as suppliments rather than the main energy supply. Orbital solar power stations are a potential solution, but they are a long way away. Though it will hopefully improve with time, as of now space travel is far too expensive to allow such a system to be economic. I still think we need something to bridge the gap between now and when we develop a clean, economical solution that doesn't have these drawbacks, and I'd prefer something cleaner than coal. If you're worried about nuclear fission becoming a permanent solution, it's not likely to happen if we develop an economical alternative, since all reactors need to be decommissioned after 50-60 years of operation. I think it's very likely that it will take at least that long before we have developed clean energy to the point in which it can provide 100% of our total energy requirement.

I think the benefits of Nuclear outweigh the risks by a large enough margin that we should continue to use it. As far as I know, these are the biggest issues with nuclear power: - Long-term nuclear waste storage - High construction costs - Danger of meltdown or radiation release - Dangers of uranium mining - Risk of nuclear proliferation - Decomissioning Most of these problems can be lessened by solutions that are possible to implement now, or will be possible to implement in the near future. Waste: Nuclear fuel can be reprocessed to capture something like 95% of the fuel, meaning waste is reduced by a factor of 20. Reprocessing does carry some risk of nuclear proliferation, as the reprocessing equipment can be used for enriching uranium. However, France has already demonstrated that reprocessing is a perfectly viable option, and the risk of proliferation is low, especially if undertaken by countries already in possession of nuclear weapons. Generation IV fast reactors are also capable of burning spent fuel without reprocessing. By implementing these reactors, we could skip reprocessing entirely, and some of them (breeder reactors) could even reprocess fuel on their own for use in themselves or other nuclear plants. There is still the issue of the (much smaller) volume of unusable waste. I believe that underground storage sites are quite safe, and that our nuclear casks are strong enough to safely transport waste to be stored. Construction Costs: This is one of the biggest hurdles to effective nuclear. Nuclear plants are expensive to build. However, either government subsidies or increased financial pressure on the cheaper coal and gas plants (for example, requiring carbon capture and storage) would make nuclear much more economical in comparison. Considering the advantages nuclear gives, I would support this initiative. Meltdown & Leak Concerns: Modern nuclear designs are very safe. There have been very few serious accidents concerning nuclear power. Both Chernobyl and, to a lesser extent, Fukashima, were as a result of lax safety standards. Chernobyl had far too many problems in reactor design, crew training, and operating procedures to list here. All design issues related to Chernobyl have been corrected in modern reactors, and crew training and operating procedures are much safer (and should be enforced more stringently by regulatory bodies). Fukashima had a fundamental flaw in that it's backup generators were vulnerable to flooding. This design flaw had been previously noted, but no attention was made to correct it. If tighter regulation enforcement is enacted, accidents of that scale can be prevented. Furthermore, the newest generation of reactors are much safer. Many Gen IV designs are "passively safe", meaning they have no danger of melting down even during a loss-of-coolant accident such as what happened in Fukashima. Mining dangers: Uranium mining is a dangerous operation. However, by reprocessing old uranium and using fast reactors that burn nuclear waste, the amount of needed uranium drops sharply. While mining uranium will likely never be 100% safe, the much lower volume needed compared to coal means that the dangers are drastically reduced. Furthermore, uranium can be recovered from seawater in small amounts. The amount recoverable isn't favorable in the current climate, but if we start to reuse most of the fuel rather than discarding it, it could be a viable way to get fuel. Proliferation: This is another big issue. It is difficult to prevent a non-nuclear-power from turning it's nuclear plant infrastructure into nuclear weapons programs. The best way to handle this is to closely monitor non-nuclear states carefully. This is not an easy task, but it's likely to be necessary regardless of whether we chose to build more plants. Nuclear states have no reason to pursue proliferation, and non-nuclear states that desire proliferation will likely want to increase their nuclear infrastructure regardless of the level of nuclear power in other countries. Decommissioning: This is the final issue, and the only one that does not have a solution available. Nuclear plants, at the end of their operational lifetime, must be decommissioned. However, I believe that despite the high expense of this process, overall nuclear power is still a valuable resource. By increasing the amount of nuclear power while simultaneously reducing fossil fuel plants, we greatly reduce the level of CO2 and pollution emission. I suggest we follow a plan to use nuclear as a transitional energy source until a cleaner, safer source of energy that can replace it is found, such as this: Begin reprocessing spent fuel, and increase safety regulation of existing plants. Build both Gen III nuclear plants and renewable energy sources to reduce fossil fuel consumption. Pursue Gen IV nuclear plants, and begin replacing decommissioned Gen II and III with new Gen IV plants. Pursue clean alternative energy sources with the potential to replace fission. Replace decommissioned Gen III and IV (and V, if it takes that long) with this alternative source. Nuclear fusion has the most potential to fill this role, in my opinion. I know that there are of risks, dangers, and problems associated with my suggested plan. However, I believe the risks, dangers, and problems associated with continuing to rely on fossil fuels, especially coal, are much worse. I think this is all the more reason to fund ITER and it's planned successor, DEMO. ITER is planned to be the first nuclear fusion break-even achieved, with the capability to produce 10x the thermal energy (which could be converted into electricity at ~40% efficiency) as what is used to run the reactor at maximum power. ITER won't produce any electricity, but DEMO (which is to be designed based on what is learned from the construction of ITER) will. Economical Fusion power is still a fair bit away. However, it's closer now than ever, and we will eventually need something to replace fossil fuels or nuclear.