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?