KerikBalm

Staging is not incompatible with re-usability. I use the term staging to mean separating your craft and then expending dV while separated. Dropping a fuel depot in orbit, and then going back to Kerbin with a smaller transfer vehicle I count as staging. Dropping your "mothership" off in orbit while sending a lander down, I could as staging. Dropping your "mothership" payload off in Kerbin orbit while sending back down the SSTO that carried it up to LKO, I could as staging. Indeed, the stages I described were all re-usable stages. You do a lot of staging events while still maintaining full reusability: 1) Single stage to space, suborbital trajectory -> circularize and then switch back to pilot it on reentry 2) Circularization stage -> if its just a fuel tug to orbit, thats the end, if its an interplanetary craft, separate this and drop it back to kerbin. 3) Perapsis kicking stage -> get your Apoapsis out past minmus and then detach this (aerobrake it later to recover) -> continue with the 4) Interplanetary stage -> only a few hundred m/s are needed on this if Duna is your target. 5) Lander stage 6) Detach Fuel depot/orbiting science lab, and return to kerbin 7) Crew transfer stage - detach a pod or send up a SSTO to take the crew back down. If you're using an ISRU mod, you can even do funky things with your lander, with reusable suborbital boosters (though refueling them and re attaching the lander's circularization stage can be quite tricky), and include a perapsis kicking stage for the return journey -> thus maintaining full reusability, but getting your staging number to 9 stages. 1) To Kerbin space 2) To Kerbin Orbit 3) To edge of Kerbin SOI 4) To target planet 5) To target surface, detach ISRU stuff/ orbital fuel depots, etc 6) Target suborbital 7) To Target orbit 8) To Edge of target SOI (same stage as #4 gets you back to Kerbin) 9) To Kerbin surface. And of course, if you are a masochist you can arbitrarily split up the circularization and the edge of SOI stages even further, to more than nine 100% reusable stages

Go into the cargo bay folders. Duplicate and rename the .cfg files set rescale factor to 4. Adjust mass and cost to your taste of what is "balanced" Profit

That ignores dreaming of course... most of which we don't remember. Brain activity continues, even if we lose full consciousness. I don't think its equivalent. I don't even think medically induced comas result in a state functionally equivalent to temporary brain death

"I just have to resign to the fact that I'm beyond this game's challenges.. " If making an SSTO was the limit you were previously at, and you've only passed it now, you are nowhere near beyond the game's challenges. Make a single stage to Duna and back. Make a single stage to Laythe and back. Visiti Moho (bonus points for single staging to Moho orbit before deploying your lander), visit Eeloo. Land and return from Eve. Visit all of Jools moons in a single mission. Making an SSTO is easy in KSP, and it doesn't mean there are no challenges left.

Well, I'm asking because I find myself using the same mission profile over and over again, with maybe 3 stage differences total (maybe an additional SRB stage to LKO, maybe an additional stage for the outbound transfer, maybe an additional stage for the lander). I've really only found that trying to visit multiple bodies (multiple moons of Jool) or Eve result in significant deviations.

'nuff said.

Yea, maybe I should have set Duna as a "standard", because the Mun or Minmus are to easy. I was also thinking maybe a Joolean moon. I typically use an SSTO spaceplane to LKO, this can lift on the order of 110 tons of payload. For RP purposes, I don't fit it with LV-Ns (a nuke engine wouldn't be very dangerous before its used, but after extensive use, a crash would be disasterous... so I never land spaceplanes with LV-Ns) If my payload has LV-Ns, I will use those. My most recent SSTO Spaceplane got a 119 ton payload to orbit (making extensive use of the payloads quad LV-N cluster), and still has 1,200 m/s of dV left (again, using the payload LV-Ns....) So, I'm planning on perapsis kicking out to nearly escape velocity, then releasing the payload (at which point, I will aerobrake the SSTO back to Kerbin) The payload was for my Jool-4 mission, which is one of the first missions I've done in a while that makes use of additional staging. So typically: SSTO to orbit + PE kicks to nearly escape velocity (Stage 1) -> release payload Single stage to destination (Stage 2)-> release single stage lander at destination(stage 3) Lander returns, may do additional landings Release fuel depot in orbit (stage 4) and return to Kerbin - often the lander is left in orbit as well Crew ferry transfers crew back to Kerbin (Stage 5) 5 stages, all reusable (the fuel depot stage is of marginal utility, why refill it when I can just put a fresh tank in orbit and deorbit the old one, no need to spend dV for docking) This is the outline for my Duna mission, my Moho Mission (which, in the end, doesn't result in much fuel being left in the fuel depot+ science lab left at Moho), my Laythe Mission, it would be the outline for my Mun+Minmus mission (biome harvesting), except I don't have the neccessary spaceplan parts unlocked by then. Then I started planning my Jool-4 mission (to visit 4 moons of Jool, Laythe is getting a dedicated mission with long term habitation structures and surface exploration craft) - and I started to move away from full reusability. -> A single lander is used, but with droptanks for the tylo landing (+1 stage) -> The mothership is designed to shed fuel tanks, as I plan on moving the mothership from moon to moon + 3 stages. Occasionaly, I have payloads that are overweight, or oversized, and not fit for my SSTO spaceplane, in which case I lift them with a 2 stage to orbit rocket consisting of a stage of SRBs, and a reusable core stage consisting of NASA engines/tanks and turbojets. I didn't need this for my Jool-4 design, but for the Jool-5 missions I was looking at, I was looking at 9 stages. Although... I wonder... after the Tylo landing... it may be more economical to just send my lander on out and return missions to Bop and Pol, than moving my whole mothership - and the lander will have plenty of dV (the drop tanks for Tylo are rather small, it was marginally able to do a Tylo SSTO, but after I tried a similar design with a better TWR but same dV, and got to a 66km x50km orbit with only 16 m/s to spare, I added drop tanks to have a good margin of error) And Eve... I haven't done it with NEAR/FAR, I suspect it won't be so bad, but.... well, the asparagus staging was strong in that one when I did it in stock... I think my ascent vehicle had about 5 stages, as did the rocket I used to get it to eve, and then I had a separate rocket send the return stage (which I could have done with an SSTO launch, but back then I was still launching everything with asparagus staging)

I guess it would be possible to perceive the early stages of death but not the final stage.

"KSP also does not simulate things like gravity gradients" Well, for 1 ship, no, but it certainly simulates a gravity gradient. The problem is it only applies a force to the center of mass, not to each part individually. As soon as you dock 2 ships... they become 1 with 1 center of mass. I suspect, much like stock "hinges", that if you manage to "hook" some girders around another ship, such that they physically interact, then you could get a gravity gradient effect, but it would be pretty weak even if your girder "linkage" is nearly 2.5 km long - and as soon as you non-physics time warp, they'll just pass through each other and that would be the end of it...

For a simple mission (land a kerbal, plant a flag, return) beyond LKO, not including "hard" destinations like: Moho/Eve/Tylo/Eeloo, how many stages do you typically use? Count landers used in orbital rendevous as a stage. For me: 1) 1-2 stages to orbit (typically, sometimes its much more for very heavy payloads, but I have little problem getting 100 ton SSTOs to orbit) 2) 1 stage to destination 3) 1 stage to land and ascend again 4) 1 stages to return to kerbin aerobrake (may be the same as #2, with a partially full fuel tank detached at the destination as a propellant depot for multiple landings with the lander) 5) 0-1 stage to return kerbals to Kerbin (either a SSTO crew shuttle, or deorbiting a capsule, or sometimes the whole thing, but I like to leave stuff in orbit for refueling) So.... 4-6 stages typically for me And the rest of you? Do your rockets shed debris like crazy, or do you enjoy lugging dead weight around?

Rapiers have the same ISP and thrust, up to 1000 m/s... turbojets top out at 2,400, while rapiers top out at 2,200 Turbojet thrust vectoring gives 2 axis control Rapier thrust vectoring gives 3 axis control Twin turbojets give 3 axis control, so that rapier advantage really only applies for very small craft I'm still puttering around with my game in .24 (using the pre-stock SPP parts, and NEAR), but I heard the new SPP parts, in addition to being lifting bodies, also have lower drag coefficients, no?

right, because genetic modification is magic and can bypass fundamental chemical constraints...

A citation I saw earlier was 7 days with no ill effects in rats. I still haven't gone to the lab to get past paywalls, but I'd be fairly confident that plants would be even more tolerant, as they produce the stuff and in many cases cause elevated local concentrations (not super high, but measurable). A week at 60% with no ill effects.... how about a month at 40? Since we're really talking about the plants here, they may not be as healthy, but if they keep on photosynthesizing, they'll keep driving the concentration up.. Strawman argument is a strawman. The initial claim, which you disputed was: "a net O2 increase from the hydrolysis of water." You stated: "Plants do not hydrolize water to produce oxygen. Oxygen gas is a product of a series of complex biochemical reactions which reduce carbon from its dioxide into carbon inside glucose ring" Which is just wrong... lets go back to this source again: http://en.wikipedia.org/wiki/Oxygen_evolution#History_of_discovery "Ingenhousz suggested in 1796 that CO2 (carbon dioxide) is split during photosynthesis to release oxygen, while the carbon combined with water to form carbohydrates. While this hypothesis was attractive and reasonable and thus widely accepted for a long time, it was later proven incorrect. Graduate student C.B. Van Niel at Stanford University found that purple sulfur bacteria reduce carbon to carbohydrates, but accumulate sulfur instead of releasing oxygen. He boldly proposed that, in analogy to the sulfur bacteria's forming elemental sulfur from H2S (hydrogen sulfide), plants would form oxygen from H2O (water). In 1937, this hypothesis was corroborated by the discovery that plants are capable of producing oxygen in the absence of CO2." Your inability to admit that you are wrong when you are so clearly wrong makes me wonder if its worth discussing anything further with you. The very first step is to hydrolyze water. O2 is released then and there. That the electrons and H+ ions are then coupled to other things is irrelevant. It simply is true. Well, as long as there is light *and* water available, obviously. Look at the photosynthesis equation... you cannot turn CO2 into sugars without splitting water... It means its possible to keep plants alive without CO2, but its not practical for growing food. For the most part, the released hydrogen is recaptured by something else (like in the CO2 dark reactions, as I mentioned, generally speaking you need 2 hydrogens to add another carbon to a carbon chain), there is a miniscule amount that gets out.. but this can be tweaked. http://onlinelibrary.wiley.com/doi/10.1002/bit.10431/abstract Its a cyanobacteria, not a plant, but the chloroplasts are just symbiotic cyanobacteria anyway, and the photosystems and chemical reactions are the same. "A. variabilis PK84 could produce hydrogen for prolonged periods (up to 40 days) without injection of fresh inoculum. During this period photobioreactor produced 24.5 L of H2. Possibilities for increasing the efficiency of light energy conversion are discussed." I don't know how extensive your college education was, nor how long ago it was... but it doesn't seem to matter. The O2 is produced when water is split. This is the very first step of photosynthesis. It can combine with oxygen, it can be added to hydrocarbons/sugars... etc. it can have many fates. In some cases the first H20 is split, and then the 2Hs combine with O from the CO2 to make water, and you may say that CO2 is releasing its O2... but if you track where the O comes from (such as using isotopes of oxygen), all the O2 gas is coming from the isotope the water was labelled with (at least initially, as new water is produced labelled with a different isotope The splitting of water producing O2 is directly analagous to the splitting of H2S producing sulfur as in the purple/sulfur bacteria. You can even have a scheme where you split H2S, and fix CO2, to make water and elemental sulfur, with no O2 release. Yea, they carry the H to other compounds(they are involved in nucleic acid, lipid, etc synthesis), and need to be reloaded with an H, and the other compounds rapidly gets very complicated. Light reactions: 2 H2O + 2 NADP+ + 3 ADP + 3 Pi + light → 2 NADPH + 2 H+ + 3 ATP + O2 Dark Reactions: 3 CO2 + 9 ATP + 6 NADPH + 6 H+ → C3H6O3-phosphate + 9 ADP + 8 Pi + 6 NADP+ + 3 H2O The net result is more sugar and O2, less water. When you metabolize glucose, it is C6H12O6+ 6O2 -> 6CO2 + 6H2O When you synthesize glucose, it is: 6CO2 +6H20 -> C6H12O6+ 6O2 Net result is less sugar and O2, more water. Importantly, (for the nth time), that O2 comes from the splitting of water. I have made a misleading statement (as I don't work with plants, I was a little rusty on this) When ATP production is desired, without generating NADPH, it mainly Photosystem I that is used, which can make ATP without splitting of water. http://hyperphysics.phy-astr.gsu.edu/hbase/biology/etcyc.html Both systems produce ATP, and their relative activities are modulated in response to the plants need to regenerate NADPH or ATP. NADPH is consumed in other reactions in addition to carbon fixation. As already experimentally shown, plants will continue using photosystem II and splitting water, even when CO2 is absent. I thought we were talking about that? Maybe I started with the wrong impression. Still, a very basic ecosystem consisting mainly of plants will likely not have sufficient feedback loops to prevent the O2 from reaching hazardous concentrations- not that it can't be circumented.

it might be hard to irrigate... if the atmosphere is very humid, then many land plants may die of fungal disease... but water adapted plants/green algae should do fine. But we don't have many plants that grow completely submerged, although I think rice should be resistant to conditions where the humidity reaches saturation.

To be clear: I don't think this is a major problem. Clearly, it is possible to have a balanced ecosystem with a stable O2 concentration. Mars is a bit tricky because there's no ready source of buffer gas, and if you just concentrate martian atmosphere (the vast majority is CO2), then the plants could easily drive O2 levels very high. Even without super concentrated CO2, plants by themselves are more than capable of driving up O2 levels well above what we are used to (both biologically, and technologically as far as fire hazards and corrosion). A properly balanced ecosystem could avoid this, of course... the problem is getting that balance while making use of what you've got available on Mars. As others have said, you could just do fractional distillation of the resulting atmosphere in the greenhouse, and get LOX for your rocket. You could even use your greenhouse to make a LOX/ethanol rocket.. or some other fuel. Of course, this is assuming you have water chemically bound in the soil, or water ice deposits just under the surface providing a ready supply of that... in which case you could just make H2-LOX fuel on site. The plants can split the water for you, but its not very practical to collect the H2 gas before some other biological process takes it - compared ot what a solar/nuclear water splitting machine could get you - but the O2 should be easy enough to capure, as should a variety of biofuels to burn with the O2. The greenhouse could provide all the fuel for a return, and food, *in theory*

Yes, aerobraking saves dV... This is news?

For sure, it would be hard, but there is nothing to suggest it is impossible. Whatever the freezing technique (that doesn't rupture membranes with crystal formation)... it won't be instant, and nor will the revival. I suspect that if it ever is accomplished, it would require lowering the metablic rate significantly (some sort of induced hibernation) before the "antifreeze" is injected and the chilling takes place. Genetic modification would probably be needed as well. But there are a number of organisms with brains (not as complex as ours, but brains none the less) that can be frozen and revived, and resume functioning. So I wouldn't write it off as impossible.

http://www.hindawi.com/journals/nrp/2011/260482/ for one... I found many, but I'm at home, not at the lab, and most were hidden behind a paywall. Strawman argument is a strawman. Fail http://en.wikipedia.org/wiki/Light-dependent_reactions#The_water-splitting_complex http://en.wikipedia.org/wiki/Photosynthesis#Z_scheme http://en.wikipedia.org/wiki/Light-dependent_reactions "The net-reaction of all light-dependent reactions in oxygenic photosynthesis is: 2H_2O + 2NADP^+ + 3ADP + 3Pi → O_2 + 2NADPH + 3ATP" Plants, and cyanobacteria, can use photosystem two to split water, generating free oxygen and free hydrogen. Just like in mitochondria, the resulting proton gradient drives an ATP synthase. Even when they don't fix carbon, they can release oxygen. Lets just take the case of simple alkanes of length n - ignoring the complexities of sugar which incorporate O, and mono/poly/unsaturated fats with the double bonds. To add 1 carbon to the chain from fixing CO2, you need to liberate the C from the O2 -> 2 O's produced... but that is not enough. That carbon also needs 2 hydrogens - alkanes of lenght N have the simple formula CH3-(CH2)_n-CH3, or nC(n+2)H Those two hydrogens come from H2O - 3 O's are released when you need to fix 1 C. For practical purposes, yes, but not entirely accurate. Right, it just hydrolyses water anyway to generate ATP when it doesn't need to fix carbon A variety of places, a simple fate is NADP+ -> NADPH - or simply into the atmosphere where other organisms in a complex ecosystem might make use of it. Yea, but that depens one what the atmosphere inside these greenhouses is composed of. If they simply run an aircompressor to raise the pressure to the point where water can exist in a liquid state, the CO2 concentration is going to be very high relative to what it is on Earth, and as explained above, basically for every CO2 you fix, you get 1.5 O2. They can, and will, when they switch more towards photosynthesis that just makes ATP, as they use the energy for more efficient recycling of the carbon they do have, and upregulate the expression of genes needed to obtain carbon sources. http://en.wikipedia.org/wiki/Oxygen_evolution#History_of_discovery "He boldly proposed that, in analogy to the sulfur bacteria's forming elemental sulfur from H2S (hydrogen sulfide), plants would form oxygen from H2O (water). In 1937, this hypothesis was corroborated by the discovery that plants are capable of producing oxygen in the absence of CO2. This discovery was made by Robin Hill, and subsequently the light-driven release of oxygen in the absence of CO2 was called the Hill reaction." Generally, yes, but if we're just talking martian atmosphere concentration to 1 ATM, the CO2 won't be depleted until that greenhouse is awash in oxygen.

Well, for the purposes of gravitation, they do. They have no rest mass, but they have relativistic mass. They have momentum

That depends entirely on how much higher the concentration is. We know that Oxygen once reached 35% of our atmosphere. That would pose a fire risk in many situations. Furthermore, you haven't cited anything as to the maximum tolerable concentration for various plants: hint, it is even higher. For mammals, it is about 60% for long term exposure. Condescend much? Most of those enzymes you refer to are for ROS, which are not pure molecular oxygen, but rather compounds produced by the ETC when doing oxidative phosphorylation. Plants produce a net O2 increase from the hydrolysis of water. O2 would build up to significantly unless O2 was again reacting with the sugars/hydrocarbons to again produce CO2 and H20. If the biomass increasess, the excess O2 increases... Of course, this is assuming only biological processes... if you can find some unoxidized chemical compounts on mars, and put them in the greenhouse, tey could soak up the excess O2, but it would be hard to have the reaction rate by high enough, yet not a fire hazard . Ie aluminum will oxidize in O2, an aluminum poweder, when given a source of heat... will rapidly oxidize and make a lot of heat...

Chaotic and unstable are not neccessarily the same thing. The paper he posted also mentions bounded orbits, implying stability. The wikipedia link says: "none of the planets will collide with each other or be ejected from the system in the next few billion years, and the Earth's orbit will be relatively stable" This all started with velocity making a reference to a time scale of 1-3 billion years: "we can't measure the positions of the planets (and other properties) closely enough to predict their orbits a billion, two billion, three billion years from now. Over such long periods, orbital resonances with other bodies (I think Jupiter being the most significant, despite its distance) can pump up the eccentricity of the orbit of an inner planet to the point where "bad things" start to happen." Then I questioned the stability within that time frame: "I've never heard any claims like this of the inner planets being in orbits unstable within that time frame..." he replied with "nothing bad will happen before the Sun dies. Most likely. " The sun won't die in 3 billion years (although it will grow quite bright), and the wikipedia link says its stable for basically the same time frame.... So I don't even know what the argument is about anymore... there seems to be agreement that its fine for the new billion years, at which point the sun will be too bright for us on Earth anyway...

Wut? that makes no sense. I'm going to go with Meithan's explanation.

CLARITY perhaps http://en.wikipedia.org/wiki/CLARITY

I'm not so sure about that. Indivudual human cells can be frozen and thawed.... its just doing it all at the same time without killing them during the transitions... And with extensive genetic engineering... why not... if a tardigrade can do it.... if some turtle species can lower their metabolism enough to survive months without any oxygen.... why not?

citation needed If there is net O2 production, I don't see why the O2 levels wouldn't continue to increase until they reach toxic levels.... which could be well after the conditions become dangerously flammable (as its thought they were at various times in the past when O2 concentration was higher) But then again.... shouldn't they be trying to use that O2 to supply the habs, where you'll have humans consuming O2?