BrickedKeyboard

Nathan : I have an idea as to how you can fix the problem with resizing stretchy tanks and recalculating fuel masses. Add 4 additional variables to each tanks to track what the tank is configured for. These variables come initialized to NULL or 0 when the tank is created. When the user clicks in the gui the button to create tanks of a specific size - such as "73% Liquid H2 27% Liquid Oxygen", set variables as such Variable0 = "0.73" Variable 1 = "Liquid H2" Variable 2 = "0.27" Variable3 = "Liquid Oxygen". Then, after every resizing operation, recompute the tank sizes based on this "forcing" setting. No more than 2 fuel types allowed with this method, but, that covers nearly every possibility anyway. Or, fix the precision errors. I suppose that might be simpler.

So, with MFS version 4, we will maybe be able to use alternate containers that look more realistic for cramming in our supplies for our astronauts?

Yes, but the reason real life spacecraft use ballast is apparently you jettison it later before deploying chutes. Just what I read, don't shoot the messenger. I hope your buddy Medieval Nerd can go and modify the capsule lifts in his realism mod.

So, apparently, the work around is you delete the line "<string name="decouplerStiffeningExtensionType7">StretchyTanks</string>" from the config file for kerbal joint reinforcement. This is still not optimal, but at least your rockets do not undergo http://tvtropes.org/pmwiki/pmwiki.php/Main/CriticalExistenceFailure the moment you blow the launch clamps.

What's the G-tolerance based on? I noticed around 13 Gs you start "hitting the G-limit" and you die shortly after. http://en.wikipedia.org/wiki/G-force#Human_tolerance_of_g-force Seems to suggest the range is a little broader than that. I bring this up because we cannot trivially get capsule lift : apparently, real spacecraft use ballast to make their capsules produce lift on reentry?

Right, but I think the bug may break it every time you go to the launchpad? I mean, I don't know : there must be a work-around. People have been proudly showing off their stretch-tank rockets in this thread and others, but I don't know how they avoid the bug.

What has to be done differently to do a heavy landing? What stops us from just using the Dragon heatshield to aerobrake, then some parachutes, then the Draco thrusters to come in for a soft touchdown? The Dragon spacecraft has a tougher hull than the Curiosity rover's exposed instruments, so we do not need to use a skycrane.

So, TLDR, let's test our closed loop life support system for the first time in microgravity on the one-way journey to Mars. Also, bone loss from 1/3 G? Radiation? Let's just risk it. Sounds like a plan. Jebediah Kerman would approve

Well, in order for Mr. Musk to retire on Mars, there would need to be a substantial amount of infrastructure in place in order for him to enjoy his twilight years in luxury. I've been trying to "rough out" a basic mission to Mars in order to get an idea if his plans are even technically feasible. Before a large base could be constructed, he would need to get a test group to Mars. 6-10 people or so. Suppose that the mission were to depart in 10 years, with 10 people, for a total budget of no more than 10 billion. Mr. Musk is worth a bit over a billion at the present time, but, presumably, he could get his buddies to chip in a few billion. Also, since NASA is willing to spend a billion per Mars probe, maybe they could sell a seat or 2 to NASA or do paid scientific research when there. Ok, so his company's Falcon Heavy is supposed to cost $120 million per launch. Assuming SpaceX is being honest about the production costs for the Falcon 9 being low enough that a launch can be done for $60 million, that seems plausible. The Falcon Heavy is basically 3 falcon 9 lower stages strapped together. Listed payload to GTO is 21,200 Kg. Using a delta-V table, I find out that http://i.imgur.com/WGOy3qT.png you need about 1.16 km/sec delta V from GTO to reach Mars, assuming aerobraking for the Mars capture and other maneuvers. That means 14,500 Kg of the payload make it to Mars aerobraking, and, assuming similar efficiency to the curiosity rover's descent system, 6,889 Kg make it to the surface. Yikes. Every Kg of supplies is $17,400. Anyways, an empty dragon spacecraft is 4200 Kg, so it looks like the Falcon Heavy is approximately a big enough rocket to get a crewed dragon spacecraft to Mars. Of course, just 1 launch is nowhere near enough. You'd need enough launches to orbit modules for the journey to Mars (supplies, living space, etc), and a bunch of unmanned launches to test the landing system and place the initial supply dump on Mars before any crew get there. But, at first glance, it looks maybe possible. I said a 10 billion budget, so if 25% of the budget were spent paying for launches, that's 2.4 billion for 20 launches. R&D for the various new systems this kind of expedition would need would cost a few billion, and there would also be construction costs to build the spacecraft. Long term, apparently, humans need something like 0.8 Kg of oxygen, 0.63 Kg of food, and 26 Kg of water per day. Theoretically, you could recycle almost all the water and oxygen, and produce at least some of the food with algae or hydroponic plants. Assuming that cuts the total supply requirements to 0.5 Kg/person/day, 10 people would need 5 Kg per day, and 1825 Kg per solar year. From above, that comes to approximately 1 dragon spacecraft stuffed full of supplies per year, which means it would only cost $120 million/year to keep 10 people alive on the surface. Now, there's a couple of show-stoppers. Well, water recycling is in use on the ISS, cutting that number down considerably if it works. However, it sure would be handy if the carbon dioxide could be converted to oxygen, and at least some of that carbon dioxide were made into additional food. To do this, you'd need algae tanks or some other method, and I could not find any information about testing of these kinds of life support systems on the ISS... I'm not certain what they are doing up there, but, apparently, recycling food and oxygen is not one of them. You could not depart on a Mars expedition without checking to make sure recycling systems actually work long term (several years) and in space environments (low gravity, radiation, etc). Similarly, it is known that zero-G exposure is bad news. Bone density loss, retinal detachment, and a long long list of other unpleasant effects. The catch is, humans have never been exposed to 1/3 G for long periods of time, either. No one knows if humans will go blind or become too fragile to move or other nasty long term effects. The only way to even find out for certain would be to put humans in a centrifuge in space at 1/3 G for several years. (well, first doing it with other vertebrate animals, but, eventually, humans) Surely they have some rats on the ISS at 1/3 G, spinning for years, right? Apparently not... This is a big problem. It looks like Mr. Musk could theoretically get together the rockets and the other systems that would put people on Mars. However, without these crucial tests, he would have no way of knowing if people could live there for long. http://www.projectrho.com/public_htm...ifesupport.php

Or electrolysis has some hidden drawback that is not immediately apparent. For example, maybe the reactor on the sub has to be in a state that is noisy in order to produce enough electricity to do the electrolysis. Maybe venting the H2 overboard causes detectable noise.

I've been trying to get a rough idea of what present-day technology could really do with regards to recycling in a life support system. The simplest method, although it would require a large amount of energy, would be you just use the "Bosch process" to recycle CO2 to oxygen, and you just distill the wastewater back to fresh. You dump the dry sludge at the bottom of the water distillation device and the carbon overboard. From the atomic rocket numbers, that means that out of the " 0.98 kg water, 2.3 kg food, and 0.0576 kg Air per day" from the "bare minimum" numbers, you would only have to supply the food externally. I'm not certain how much leakage would be. Does anyone have any realistic numbers on this? I know the in-game life support recyclers assume 50% losses, but that sounds ridiculous. Other than a tiny amount of air leaking from the spacecraft, it's a closed system. Where could material be lost from? https://archive.org/stream/nasa_techdoc_19710002858/19710002858_djvu.txt A slightly more advanced life support system might supplement the food with, say, 50% algae. That would mean you would only need to bring half the food, and perhaps 10% of the water and oxygen, to make up for losses, per day per crewmember.

Apparently, there's a patch from KSP Interstellar posted in this thread. Page back a few. Oh, it's in the MFS thread, I think.

I take it numbers from Atomic Rocket aren't good enough? It gave the following numbers in kg/Liter. Since both liter and m^3 are volume measurements, you just multiply to convert. There are 1000 liters in one cubic meter. Frozen meat and veggies : 375 Kg/m^3. "fresh" foods, 250. Dry/canned goods, about 500. From handling MREs, I know from personal experience that dry foods are not that dense. Even if you removed the air from the MRE package, it will not have that much density. Another factor here is that I don't think it matters that much. Since volume is cubed, I don't think that current missions have to optimize for volumetric density so much as reducing the mass. If you make the payload section of your rocket slightly longer, it will only have minimal effects on the air resistance. (while, for a given rocket design, increasing the payload mass comes up against hard limits) So I would pick the lowest of these numbers. Imagine a food storage pantry filled with stacks of compact MREs, with extra space around them so that kerbonauts can get to supplies at the bottom of the pantry.

Why do this instead of electrolysis? I thought the O2 candles were for emergencies only.

What causes the 2fps frame-rates? This mod, another mod, or a slow computer?

Can someone break down the current LS situation? As I understand it, ECLSS murders performance and is currently unplayable, with most posts on the thread for that mod complaining of FPS loss. TAC "works" but apparently is not using realistic numbers? (and it doesn't simulate electric power, although, at least it runs faster) So if we want to use ECLSS, we have to deal with bad performance, and if we want to use TAC, we have to dig up a config file for it to adjust the numbers? Does that sum it up? Have there been updates to ECLSS that fix the performance issues?

What's the deal with the "M/s" support for the nav computer. I do something like set up a maneuver node, press the button to aim the spacecraft at the node, and type the length of the burn followed by "m/s". It does not burn until however many m/s I specified have been supplied by the engine, it burns for that many seconds and quits. Is there an exact syntax? Do I have to type it differently, like "ms" or something?

I also tried a "sticking out of the VAB" rocket. The weird thing was that it launched perfectly the first time, but then upon reverting back to the VAB to tweak it, it never launched right after that. I would get crazy amounts of flexion at the connection points between stages, and no amount of struts was enough to help. So, is this due to this "OnLoad()" bug. Is there any work-around, or are we hosed until the update? I was able to get messy asparagus rockets to work just fine with stretchy tanks. Come to think of it, I had trilateral symmetry and a lot of struts connecting it all together.

For us newer aerodynamics optimizers, is there a way to tell how much delta V a rocket lost to friction? It occurs to me that the easiest way to refine a rocket design would be to just A:B test. For instance, does a procedural fairing help much? Leave the fairing part off the rocket in the VAB and launch. Check the delta V lost to friction. Then launch the same rocket with the fairing. In theory we could answer a lot of questions this way, including things like whether an extremely long and skinny rocket is better than a shorter and fatter one. It would also tell us how much delta V we are losing with horrendous Asparagus designs, versus a tall and skinny rocket.

Agree. It took me a couple days, but I now realize what is unrealistic about Fractal_UK's waste heat model. As I understand it, only pods with heat dissipation and radiators vent waste heat. The solar panels themselves do not radiate away waste heat, nor do other ship components. That is unrealistic.

I understand your point of view. However, keep in mind that while I am new to this game, I have about as much technical skill as anyone. Instructions that are split between multiple pages, buried in forum posts, etc, and leave critical information out cannot be followed by anyone who isn't an expert at KSP's internal systems. Furthermore, I know from long experience with minecraft that no one played anyone's mods until it become 1-click easy. You can whine all you want about the extra effort, but that's the fact : mods were virtually never played, except by a tiny (but vocal) minority until they made launchers and ways to load huge modpacks all at once. If you want your mod to leave alpha, all the files you can legally get away with need to be in a single folder, ideally one that uses an excutable installer.

Where? I wouldn't have asked if this was obvious. Every screen available to me does not show this, so far as I can see.

Alright, how do I optimize for the best possible TWR to get the most out of each stage? I realize now that in this game you want to optimize for maximum performance/stage because each stage is the same number of parts - a tank + engine + struts and decouplers. (times however many you need for a reasonable amount of thrust) Anyways, it's a math problem. Say you choose a TWR of 1.0. Then, you'll have to burn some fuel off to get anywhere, and once you do, you are carrying empty tank mass. So 1.0 can't be the optimum. The "1.2" that Nathan gave sounds like it is probably closer, since empty tank mass is fairly small, but how would I set up the equations to find out exactly what the right TWR is for a given tank : fuel mass ratio? Another thing : is there any easy way to determine how much energy I lost from drag for a given rocket design? It occurs to me that I don't actually know if using asparagus staging or vertical staging is better in this game under these conditions. If you do vertical staging, you are carrying the dead weight for the engines of the upper stages, but you have less drag. With Asparagus, you don't carry that dead engine weight and you also carry less dead tank weight if you set it up for a lot of small asparagus stages. If I could check a readout somewhere that would tell me how much delta-V was taken by aerodynamic drag, that would let me do a direct comparison.

Apparently, the memory reduction mod really works, sirklick. Using MedievalNerd's recommended installation I'm down to 2.46 gigabytes on load. (well, I did install the reduced texture packs for KW and NP and AIES)

I have to do this? This is not already done in the tweak file included in 18b? I have to ask because if I do this but it was already tweaked, then I'm decreasing power costs by a factor of 100...