KerikBalm

yes, I know the benefits of high AR wings, I just misinterpreted the desription or wha FAR does. My initial interpretation of the FAR description was that it was actually penalized high AR wings

Ahh, I misunderstood the description of what FAR was doing then. So the way FAR works, high aspect ratio wings are indeed better (as they should be)? I was imagining this |\ |\ |\ |\ (lets say each of those "\" is a swept wing, and "|" is the fusalage) would count all the wign peices as "root" peices and this: |\ |_\ |__\ |___\ (Ignore the "_"s they're just for spacing) Would be counted as 1 root, and 3 "tip" peices, or maybe 1 root, 2 normal, and 1 tip, and would perform worse. When in fact the first one would be counted as 4 tip peices, and the 2nd one would be counted as 3 root and 1 tip peice if I understand FARs rules correctly?

The question is to vague... in the universe? in the multiverse? in the observable universe (given that the expansion of the universe will create event horizons between us and distant points), the galaxy? What qualifies as a civilization? Would something like an ant colony count? are we only counting those that can send signals (of any sort, although there isn't much plausible aside from EM radiation) into space? only those that can navigate space? FWIW, I do not believe there are any civilizations that are capable of interstellar travel within our galaxy. Therefore I believe we would be the first if we were to acheive fusion power. FWIW, I got 0.5 billion planets with intelligent life using that calculator, and I think I was being generous.

I don't see why you can't have both... which is what they do in Halo anyway, so.... But I'd say biological for a villian. Imagine you take stem cells, re-encode the genome to use an alternate "code" (ie the triplet codon to amino acid mapping), inject them back into yourself, wait until most of your body is re-encoded cells. Simultaneously to the re-encoding, you also make it so that your body naturally produces a variety of very deadly viruses that can be exhaled at will. Due to the re-encoding of your cells, you would be immune to all viruses (currently) in existence, as a virus uses the host cell machinery to translate its nucleic acid code. If the host is using a different encoding, the virus genome gets translated to gibberish. Someone with a re-encoded genome would also be a seperate species. The villian now looks perfectly normal, but is a walking biological weapon. No suicidal release of a dangerous pathogen. No very suspicious release of a dangerous pathogen while wearing a hazmat suit. No suspicious sealed package. Internal cellular production of pathogens. No one would see it coming. The villian would only need to get close to the hero(ine), breath on him/her, and walk away.

http://www.projectrho.com/public_html/rocket/enginelist.php According to this, a solid core NTR will have an exhaust velocity of 8,093 m/s with hydrogen propellant. This is a specific impulse of 824 maximum. 800 is rather realistic Of course, you can incrase that by disassociating H2 into monatomic hydrogen... but that will increase the complexity and weight even further. Or you can increase the temperature even more, but then you might have problems with erosion of the fuel rods and radiactive exhaust. Of course, it won't be as bad as a gas core NTR

I'm not even sure there is a theoretical benefit, although I haven't done the math. Consider a perfect sphere (or an attempted landing atop the highest poin on the surface) - in this case you can set your perapsis arbitratily low. you can thus circularize into an orbit arbitrarily low over your landing site, while burning perpendicular to gravity the whole time, making your gravity drag essentially zero. In this case from an arbitrarily low orbit, you need only to arrest horizontal velocity to land, no burning pointing at the surface required* Meanwhile, if you come in on a trajectory perpendicular to the surface, you may lose significant amounts of dV to gravity drag, although the higher your TWR during the "suicide burn", the less this is. * but, to pull off that horizontal landing, from very low orbit, you need a very very very high TWR, otherwise you will drop into the surface while you still have significant horizontal velocity. Of course, with an arbitrarily high TWR, the suicide burns dV lost to grav drag also approaches zero... so.... If you manually pilot (maybe mechjeb can pull it off better), getting the suicide burn right is pretty difficult - the sooner you have to start the suicide burn, the more likely you'll end up with too much of a margin of error and lose a lot of dV to gravity drag as you slowly descend, and the more likely you'll need too much "lithobraking". For me, manually piloting everyting (I don't have mechjeb), I always end up using less dV by capturing into a low orbit, and then doing my suicide burn from a low altitude. I can get much more precision. I'f I'm coming in at a very shallow angle, and see I wont stop in time, I can point the thrust down a little bit (sure, losing some dV to grav drag there), to buy more time. When I do direct landings, I usually end up wasting a lot of fuel slowly descending from 1 km above the surface or something like that. I'd say the maximum theoreticaly benefit is probably less than 10 m/s, and in practice, you'll end up spenidng more than that on landings due to a lack of precision and sufficient error margins, or crashing spacecraft due to a lack of precision and insufficient error margins. Unless the body has an atmosphere, I always capture into a low orbit before landing.* * also, assuming you want to get back to Kerbin, leaving the fuel you need to get back to orbit is much more efficient in many cases- ie doing it "apollo style". Although in this case you must consider the dV needed for docking maneuvers and the docking port weight. For the two moons of Kerbin, its often not really worth it (but I still do orbital rendevous with an orbiting fuel depot + science lab to collect science from many biomes), but as one moves on to other bodies, like Tylo and Eve especially, you'll always want to capture first, and then use a lander and orbital rendevous.

Yea, you need FAR for the aerodynamic nose cones to actually be useful. I mod them so they act as small fuel tanks(same mass ratio as the other tanks), so they look better and are functional.

Well, I can get to orbit with stock parts, and I even got to orbit with a LV-N upper stage that could likely take me to mars.... As far as I can tell, the LV-Ns are pretty realistic as far as TWR goes. I think I calculated before that each engine must be putting out at least 200 megawatts of thermal energy. I'm not quite sure what reactor outputs are, but that sounds reasonable, and from what I've ready about NERVA engines, they did get over 1:1 TWR, but it was still pretty low. Anyone got an answer to the Duna "Mars" atmosphere density? Did they just make the planet bigger, or has the atmosphere been changed as well? I don't want to install too many mods, as I said, just RSS and FAR are already not behaving well on my computer. I'd rather just do some text editing to tweak the TWRs and the mass ratios of the tanks to realistic levels.

So I finally converted and installed FAR and RSS on an alternate save of KSP... and wow... getting to orbit is hard. The SLS parts that seemed OP'd before don't seem so anymore. I was aware earlier that KSP parts are underpowered (mainly, the engines TWR is way too low, and maybe the tanks are too heavy)... What are realisitic TWR ratios and Wet:Dry mass ratios for the tanks? (I guess the ISP is also too low for some liquid hydrogen-LOx engines) I don't want to hyperedit or anything, and the mods arent very stable on my computer... I haven't made it to Mars/Duna, as my larger rockets invariably cause a crash at some staging event, and I don't even get to orbit. As it is supposed to be the real solar system... have they adjusted the atmosphere of "Mars" appropriately to the point that at the lowest elecation the pressure is only 0.0087 atms... so that the only stock parachute that will deploy is the drogue (and if so, good luck decelerating in time if it deploys at a pressure of 0.007 and impact is at 0.0087 atms)

Sorry if that was unclear, I meant the dV needed to land if you've done no circularization is greater than the dV needed to land after you've already circularized. Ie: 400 to land with no circularization vs 200 to circularize and 200 to land. 400>200, so although you skip circularization, you pay more for the landing, and basicallyend up spending the same amount of dV. I did not mean to imply that doing it his way costs more dV. I only meant to imply that the savings are miniscule and far far less than the 500 m/s claimed, and I think we can both agree on that

Can anyone tell me why "wing pieces at wingtip make less lift and more drag than ones at wing root" This would imply that low aspect ratio wings are better than high aspect ratio wings.... which seems a$$ backwards

I thought the brakes could only be set in the VAB.... You left out one thing, and that is the motors.... When going up a steep hill, if my rear wheel motoers are on, and my craft is too light, it can end up back flipping. (I've built many rovers capable of "popping a wheelie" if the rear motors aren't disabled) When going down a hill, if my front motors are one, and I'm not using brakes, but rather the motors to decelerate, it may flip. To avoid flipping, you always want your motors in front of your CG ("front" being the direction of travel) to be active and pulling you. I've made a few mobile lab based landers: This one is a development of my Mun rover. The original rover design was delivered by "sky crane" (ie, slung under a large lander). I'm pretty sure I could make this atmospheric design work without the parachutes (might need to add small gear bays for faster landing speeds) and/or decoupling wings... but I like it just for the cool points of steering its trajectory on the way down... gliding close to where it will first do science... then I pull the nose up and hit the staging -BAM, wings decouple and parachutes deploy, and when roving, no more unsightly wings. (note its called an EVE lander in the sub assembly, the ascent vehicle is obviously sold seperately ) The only problem is that Eve only has 2 "biomes", and once it is in the "oceans" biome, it can't get back to solid ground - which currently isn't a problem for maxing the science, but it does mean the kerbals may have a long walk to the ascent vehicle with just their space suit for protection - but solving that issue is for another thread. btw... bunny hopping is fun, it finally gives an incentive to do things "apollo style" I don't use a massive lander, I use a small lander, and an oribiting station consisting initially of a Liquid fuel/oxidizer/monoprop fuel depot, and a mobile lab+ solar to run it, and a hitchhiker "habitat" (later I add Ion thrusters and Xenon storage). It makes for good orbital rendevou practice. It is after all a space flight game, not just another driving game (although, I don't know of many "low gravity" driving games)

No it doesn't - the dV you use to decelerate for landing is greater. Suppose we have a 200 m/s capture burn, and then need 200 m/s to go from low orbit to landing.... for 400 m/s total If you skipped a capture burn, you'd be coming in even faster, and you'd need ≈400 m/s to land. The only fuel savings are from the oberth effect, but that is miniscule assuming that you capture into a very low orbit

Couldn't you also use the Mun to get you into a polar orbit.... assuming that doesn't count as raising your apoapsis to an insane height (hey, its not like you're going to minmus!) Like so: http://en.wikipedia.org/wiki/PAS-22#Rescue_of_satellite

Electric atmospheric propulsion... eve and duna solar gliders please (laythe too I suppse, but jet are so darn efficient, that its easy to get around laythe Kerbin is where this is most noticable... there are almost no signs of civilization. Meanwhile... Minmus, the Mun, moho seem detailed enough. From orbit, Duna seems detailed enough, but once on the ground... its meh, too "low resolution" maybe more side channels feeding into the main channel, slope lineae, polar geysers, and stream beds/inverted streambeds around the edges of the "old sea floor" (I'd still like to keep the old sea floor smooth). Eve.. meh... more channels to be more like titan? Eeloo... haven't visited it... I'm not sure what you want out of an ice ball Laythe - I don't know, how about some variations in the sand textures... have higher elevations have a different texture, as if they've been out of the water longer. Maybe some darker spots from recent volcanic activity? Hints of life? voted for better aerodynamics, but biomes was my 2nd choice.

You are right.... if at terminal velocity Grav drag = air resistance, lets just call the quantity for each form of drag "D", total drag is thus 2D So at 10% faster than terminal.... we should have 1.21D + 1/1.1D = (1.21+ 0.90909..) D = 2.119D 2.119/2= 1.0595... so yea, I agree, 6% more... or... about 60 m/s... Interestingly it would seem then that going 10% under results in (.9^2)*D + 10/9D = 1.92111D.... which would be more efficienct... O.o ? So then total drag would be D(X^2+1/X).... so the derivative of that is 2X+ (-1)X^-2 The minumum would occur when that equals Zero, so when 2X= 1/X^2 -> 2= 1/(X^3) -> X^3= 1/2 = cube root of 1/2 (ie, about 0.79) So.... I must be calculating wrong somehow if my equation concludes that the optimal ascent velocity is about 80% of terminal velocity... Oberth effect or something? Maybe I'm calculating to minimize dV losses, when its actually better to use the dV better (ie oberth effect, not all dV changes are equal), and accept some higher dV losses to drag.

*edit* AHHHHH....... I seee..... I used the wrong landing legs! I used the heavier ones anyway, so it should work even better Also, I forgot to mention, since you don't have RCS thrusters, drain all the monoprop from the command pods before launching them(do it in the VAB with the tweakables), that'll get you a little bit more of a margine Well... took me longer to get around to it than I said, but here is the craft I made: 1st stage engines firing: 4x rockomax SRBs, 1x LV-T45, 2x LV-T30s 2nd stage: SRBs decouple, the 2nd LV-T30 pair fires, total engines firing: 4x LV-T30s, 1x LV-T45 At this point, it should be full throttle the rest of the way to orbit 3rd stage: one LV-T30 pair decouples 4th-ish stage: both LV-T30s decouple, followed very shortly thereafter by the LV-T45 decoupling, the next one fires, as do the 2x L-909s above the decoupler 5th stage: LV-T45 decouples, the LV-909 above it fires (so 3 LV-909s going now) You should be just about to orbit when the LV-909 pair runs out, which leads to stage 6 6th stage: LV-909 pair decouples, leaving just 1 LV-909 to circularize and begin trans-munar injection 7th and final-ish stage: the LV-909 decouples, and the 2two LV-909s above it fire: These complete the transmunar injection, capture, and landing. When landed, have your other kerbal get in the free command pod. And (important!) transfer one of the FL-T200 tanks each to a different FL-T400 tank (since I'm assuming you're doing this without fuel line tech) You should have enough dV left to get the whole thing to munar orbit, and back to kerbin, if you're cutting it close (or for coolness points), you can decouple the FL-T400 tanks (along with their attached pods, parachute, and engines) from the center FL-T200 stack, that way each rocketbal pilots his own rocket back to Kerbin. You can also have them leave at different times if the rescue kerbal wants to stick around for a few more Munar orbits.

Well, for 10% faster, in that case, its 1.1^2 = 21% more air resistance, while your gravity drag is reduced to 9/10ths... At terminal velocity, gravity drag = air drag, and we can thus say the total drag has increased by 9/10*1.21 = 1.089.... almost 9% more drag. Of course, the other question is what is your total dV lost? if it were an airless body, gravity and airdrag would be miniscule- you thrust up for a few seconds (so... lets say 30 m/s of grav drag), and then point horizontal and go full throttle, racing to the horizon. Then to make it equal, you'd do a hohman transfer to a 75km orbit.... You need ~4,500 to get to LKO... at that speed, your orbital velocity is about 2,300 m/s, so... you spend about 2,200 m/s getting to that latitude, and fighting the various forms of drag. For simplicity, I'll assume gravity is constant, 1/2 Mv^2 = mgh m cancels out, 1/2 v^2 = 9.8*75000-> v^2 = 1470000 v= 1212m/s so raising your apoapsis to 75km altitude requires approximately 1200 m/s of velocity (granted the gravity falls off, and you'd do a gravity turn, not shoot up to 75km from a 1200m/s vertical burn, then burn perpendicular for another 2,300 m/s) Anyway, as a very rough number, you'd spend 3,500 m/s getting to a 75km orbit if Kerbn had no atmosphere, but with an atmosphere and optimal ascent, you spend about 4,500, so lets say you lose roughly 1,000 m/s to gravity drag and air resistance. Since 10% faster than terminal velocity should result in 8.9% more total dV loses, I'd say take 1,000 m/s and miltiply it by 0.089... I'd estimate going 10% over terminal velocity costs you about 80-90 m/s

Well it seems to me it is highly dependant upon the engine. For a better TWR engine, having a higher TWR isn't so bad. "b) TWR > 2, but thrust limited to terminal velocity is second best. It is not cost effective, but it is fairly delta-v effective." In this case, we'll assume it starts at a TWR of 2, and then by the end of the stage is higher than 2. In this case, you throttle down as your stage burns. The result is that you lift more mass in engines than you need, paying a dV penalty. If these are LV-Ns, the mass is significant. If this is a 48-7s then you haven't lifted that much unneeded mass. Asparagus staging reduces this penalty by giving more stagign increments, so that unneeded engines aren't lifted that far. "c) TWR which keeps you near terminal velocity is third best. Split over and under terminal velocity based on changing TWR or ease of control or staging." I think this is best for convenince, given that this is a game, and playing time is limited, rocket size is not. "The total drag goes up because atmospheric drag goes up faster than gravity drag goes down, but the total doesn't go up that quickly." Air drag increases with the square of velocity. Going 2x terminal velocity only halves gravity drag, but it quadruples air drag. As far as air/gravity drag is concerned, its a better to go slightly under terminal velocity than slightly over. We could easily make an equation to show this, gravity drag being Ksub1*1/Velocity, and air drag being Ksub2*Velocity^2 (assuming a 90 degree ascent) But, as you point out "The faster you get out of the soup, the better that engine performs." - althought this isn't a consideration for the aerospike - but I don't think this is valid. You can have your engine performing under a certain ISP for 30 seconds, or 45 seconds, depending on your throttle.... but the 30 seconds isn't really better if you are burning more fuel in those 30 seconds than you would during the 45 seconds. You still go from 0 to x meters in altitude with your engine at Y ISP. Halving the time at that altitude, but doubling the fuel used per unit time, doesn't save any fuel (yes it saves gravity drag, but then loses air resistance). I think the speed for optimal deltaV is best. What it could affect, is at what altitude you start your gravity turn.... you'd want to spend as little deltaV as possible in the lower atmosphere spending most of it to get higher, not faster horizontally-but given the KSP aerodynamic model, by the time you start your grav turn, your engines are all nearly at vacuum ISP anyway. You spend your dV to get higher to reduce air drag, the improved ISP is insiginficant in comparison. Another point: especially as you get higher, you need a TWR of better than 2 to maintain terminal velocity, because it increases rapidly. A TWR of 2 can maintain a fixed terminal velocity, but if you need to accelerate 1,000 m/s in 10 seconds to maintain an increasing terminal velocity, a TWR of 2 will not cut it... so you want something slightly better than 2, so you can not only maintain terminal velocity, but also accelerate to reach ever higher speeds, as TWR increases faster. At low altitudes, you may need to accelerate 1 m/s to keep up with terminal (basically .1 G), at higher altudes, its more like 100 m/s (ie, 10 Gs). Of course, packing enough engines on your upper stage to get a 10:1 TWR also means lifting a lot more mass... which is less optimal. But... once you start your gravity turn, you don't actually want to follow terminal velocity. You want gravity drag to equal air resistance. Gravity drag is not Ksub1*1/Velocity, but rather sin(theta)*Ksub1*1/Velocity - as your velocity vector gets close to perpendicular, gravity drag starts getting lower (not even accounting for the strength of gravity getting weaker as you get higher, which is more apparent in KSP than real life). Once you start your turn, you want to start lagging behind terminal velocity (and that at certain altitudes, terminal velocity is higher than escap valocity, should make this apparent) So... there are a lot of variables, and the answer would change depending on what engine you are using. At least... thats how I figure it.

Hrmm, I don't know why it says the parts are invalid, I tried to use only parts I saw you use in the screenshot you posted. Try opening it in a sandbox game? if not, I wonder if I modded one of the parts and forgot about it. I'll show a screenshot later today

Not true, you can make room for another kerbal by adding a second command pod (make sure no one is sitting in it at launch). Of course, later, you can just slap a probe core on it, and launch with 1 empty pod, but for now a rescue means you must take two pods Here you go: https://www.dropbox.com/s/ra3r08huizh01ab/Mun%20Rescue.craft this should get you there. I had a smaller craft, it was a bit more complex with action groups, and required a pretty optimal ascent ot orbit. This one is simpler to fly. Full throttle, fire engines As the 1st stage gets lighter, throttle back to maintain optimal ascent velocity When the SRBs run out of fuel, full throttle, and keep it that way until you're in orbit After landing on the Mun next to your kerbal, have him get in the other pod. Here's where It gets a little needlessly complex - while you should have plenty of dV remaining, in case you find yourself a bit short: The central stack of 2 FL-T200s-> transfer that fuel into the side mounted FL-T400s (the ones under the command pods), then as you're at nearly low mun orbit, fire the decoupler. You've shed some mass, and now have 2 separate ships, your stranded Kerbal is a rocketman after all, and wants to take his own rocket home, not just be a passanger on someone else's rocket Fly each one back to Kerbin.

http://en.wikipedia.org/wiki/Double_planet#Definition_of_a_double_planet It can orbit our planet, and our sun. anything orbiting at near escape velocity will have the sun "winning the tug of war" I don't see any value in placing an arbitrary distinction at the ratio of 1:1 , for what constitutes a true moon, or a binary/double planet. As to the OP's question, I think it would take highly unusual circumstances to result in a stable orbit, but I'm sure there are cases out there

Not obsolete, just simplified. I still make designs with side boosters feeding into the core stage, most I've done is 4 asparagus staged radial boosters

Maybe he just wants to learn orbital rendevous... and has a mind to set up a science lab+ fuel depot in orbit around Minmus to harvest all the science

Yea, I don't think 3 intakes is spamming... 12 is though Triple your intakes, and you triple the air you get, which means you can fly in 1/3 the air, and thus 1/3 the drag - when you have a perapsis while still flying on jets... you've done too much intake spamming. Most of the SSTO designs i see that perform really well make heavy use of intake spamming and part clipping, I don't do either (assuming 4:1 intake ratio is not spaming, and I use more radials than ram intakes, because... as I said, no part clipping for me)