Northstar1989

I can't say I understood every relation between RO and the mods it requires, despite having reading the OP. That's exactly why I started this thread- to pick up on as many details relating to modding for greater realism as possible. I want to educate myself before I give anything a try- especially since to make room for realism mods, I might have to uninstall some other mods... I have no intention of playing with RO, though, after reading it requires "Advanced Jet Engine" (which inaccurately nerfs jet engine ISP), and several other mods I'm not comfortable with implementing just yet, or don't have the memory for on my laptop... It's quite a laundry-list of mods it requires: have you ever considered cutting it a bit shorter? I'm not so sure about things when I hear phrases like "based on a judgment about their technology level" being applied to solar panels... That's subject to a LOT of judgment on the mod author's part, and in my experience, people tend to rather underestimate solar panels potential in real life... There are all sorts of breakthrough technologies coming out in the solar industry- and I prefer to think (and play) with the Kerbals as being a little ahead of our current technological era in some ways, rather than trapped with 1970's technology... It also creates problems in that you need to keep electricity production and demands in their proper balance, and if you nerf solar panels without decreasing the demand of unrealistically power-hungry parts (which will be basically anything designed to balance against stock solar panels), you'll just end up making them weaker than in real-life from a usefulness perspective... Regards, Northstar

I've dedicated quite a bit of discussion to that already. Although I'm not an engineer in real-life (I'm a biologist), and had to just look up "ballistic coefficient", it's precisely what I was describing all along... The problem is, 64% scale rockets have a lower ballistic coefficient than real-scale rockets, due to their not being as tall/long... http://en.wikipedia.org/wiki/Ballistic_coefficient#Formula It can be clearly seen right in the second version of the formula: ballistic coefficient is proportional to body-length times density. A 64% scale rocket is 64% as tall, while having the same density (in theory- in reality, KSP densities are also all messed up...) Indeed I did. I'll take a look. Regards, Northstar

Hey, lay off Geschosskopf. He's growing to become a good (virtual) friend of mine, even through the course of arguments about the feasibility of interplanetary colonization, and the fate of humankind... And, I rather respect his work on the Flying Duna Challenge (even if I can't agree with *all* his judgments- like disqualifying one of my spaceplanes from SSTDABK for an in-flight refueling while on escape trajectory from Kerbin), and the Kethane Traveling Circus... It doesn't hurt he's kicked a few reputation points my way either... Not precisely. It says right on the release page for Realism Overhaul that the compatibilities for quite a few of those mods are "partial"... It also turns out it requires quite a few other mods- including one in particular that I have some issues with, and refuse to play with until it's fixed, "Advanced Jet Engines" mod- which makes the MAJOR mistake of nerfing jet engine ISP, even though it turns out it's actually quite (surprisingly) accurate/realistic... (the TWR's on the other hand, are insanely OP'd) My favorite mod of all time. One more reason for me not to use Realism Overhaul. Flight Sim's aren't really to my tastes either- and I simply can't understand why anyone would play them.. I was always a kid who grew up playing Legos. These days, I enjoy games like KSP and Minecraft- not a game where everything's already been planned for you ahead of time... Regards, Northstar

Yeah, it appears I did miss a few posts. I'm not sure how- though I think part of the problem might have been having so many tabs open at once (I've been doing a *LOT* of background reading on the efficiency and mechanics of jet engines in real life- of which I previously knew almost nothing. Luckily, I'm a huge sponge for information, with my sky-high IQ... If only that applied quite so well to social skills...), as well as an anti-virus scan, a calculator application, and an annoying pup-up or two in separate windows... I now know that (surprisingly) the stock engines are actually quite realistic- real world turbofan engines really do act like they have ISP's in the tens-of-thousands (29,000 m/s effective exhaust velocity is the generic figure for a turbofan engine on Wikipedia: the stock turbojet acts like it has an effective exhaust velocity of 40,000 m/s), due to all the inert air they accelerate through them- but I managed to miss quite a few relevant posts on my own thread... Regards, Northstar

Actually, none of this is necessary. The stock rating for ISP are correct. A "turbojet" (turbofan according to game internals) engine has a listed ISP of 2500, for instance. This is not at all unrealistic- the example table for ISP's on Wikipedia lists a turbofan's ISP as being 3000: http://en.wikipedia.org/wiki/Specific_impulse#Examples It gets better though, because the inclusion of IntakeAir in generating propulsion (thrust) is actually quite accurate. This is everything I was saying before about "Effective Exhaust Velocity" being the term you really need to look at... In real life, a turbofan engine propels the entire mass of both fuel and intake air, just like it does in the stock game. Because it takes exponentially less energy to produce the same thrust with a greater mass of propellant, you actually get a term known as "Effective Exhaust Velocity"- which is defined as the exhaust velocity that would be required to produce the same thrust in a vacuum. Wikipedia sums it up nicely as follow- capitalization added: "For air-breathing jet engines, particularly turbofans, the actual exhaust velocity and the effective exhaust velocity are different BY ORDERS OF MAGNITUDE. This is because a good deal of additional momentum is obtained by using air as reaction mass. This allows for a better match between the airspeed and the exhaust speed which saves energy/propellant and enormously increases the effective exhaust velocity while reducing the actual exhaust velocity." You are absolutely correct about the thrust being overpowered (by at least 3-4 times what it should be), and the velocity curves being dodgy though. No change is necessary to the stock ISP calculations, or inclusion of IntakeAir in the thrust system. It approximates real-world Effective Exhaust Velocity closely enough (once again: 40,000 m/s effective exhaust velocity is entirely within the realm of possibility for real-world engines...) The main problems with jet engines in this game, is that they produce more thrust than their real-world equivalents, while actually being much smaller and lighter; and the planets they operate on in the first place are much smaller than their real-life analogs. If you want to pursue realism, cut the thrust of the jet engines to about 1/4th their current values. The ISP calculations should be left alone though- they're quite accurate... Regards, Northstar P.S. The stock fuel-density (too low), fuel-capacities (much too high for their size), and fuselage weight (much too low for their strength) are also screwy. This may also be responsible for the perception that stock jet engines have too much endurance... P.P.S. Although I can tell you the ISP values and calcuation system in the stock game are more-or-less correct, it's been a *LONG* time since I performed an endurance-test with jet fuel-burning engines, having long ago switched almost exclusively over to Thermal Turbojets for their much greater endurance and ability to operate on Duna. So I couldn't tell you how the range/endurance of approximate replicas of real-life planes would match up given all the differences in TWR, mass values, orbital velocity, and even drag ratios (64% scale craft necessarily have more drag compared to volume relative to their full-sized versions- as they aren't as long, and have a worse surface area:volume ratio)

Before you go off an a grandstand about how the stock engines last too long, however (they do, that's true), and can travel too far (that's a distinct possibility- though see my note on scale below), and therefore MUST have unrealistically-high ISP (they don't), consider these three factors: (1) You might be comparing performance on stock Kerbin, or some other Earth-analog that is at a miniature scale (anything less than a 100% scale Real Solar System install, basically). On such a small planet, orbital velocity near sea level is a measly Mach 7 or so... So any supersonic aircraft you build is going to reach a *SIGNIFICANT* fraction of orbital velocity- which means it's effectively in a partial state of free-fall, and experiencing less gravity than a comparable-speed aircraft would in real life. (2) Stock parts are 64% scale of those in real life. Which means that, if an engine has precisely the same thrust as the real-world engine it is imitating, it has 144.14% more thrust than it ought to (I am making the gross assumption thrust should be proportional to cross-sectional area. A real-world engine has 244.14% the cross-sectional area of a 64% scale miniature). Forget what I said a second ago about the mod creator using the wrong thrust values- because the thrust values he should be using should be less than half of the real-world versions due to the smaller scale. (3) Stock parts *DO NOT* imitate real-world engines. They often exceed the thrust of real-world versions, despite being 64% scale miniatures... I think it becomes rather obvious the reason stock engines out-perform their real-world analogs is due to a combination of insanely-overpowered Thrust-Weight-Ratio ratings, and lower orbital velocity on Kerbin than on Earth. Don't also forget that if a jet plane can circumnavigate Kerbin, this is only the same distance as flying about 10% of the way around Earth... (So when you hear people complaining they can circumnavigate Kerbin 3 times with their long-range aircraft at high altitudes, and that is "overpowered", remember that's still only the equivalent of flying 30% of the way around Earth: with space-grade materials and engineering...) Regards, Northstar

You're right that in real-life, ISP only is based on fuel-flow, but for jet engines you need to look at the more relevant parameter of "Effective Exhaust Velocity". Cutting to the chase, because thrust *IS* produced by accelerating the air that passes through a jet engine, as well as by the expulsion of the fuel itself, and it requires exponentially less energy to produce the same thrust with an increasing mass of propellant, what you get is an Effective Exhaust Velocity of 29,000 for a turbofan engine in real-life. http://en.wikipedia.org/wiki/Specific_impulse#Examples What that means is, a turbofan engine produces thrust consuming fuel at the same rate as a rocket engine with an ISP of 29,000 would in vacuum. This is due to the increased efficiency from propelling inert air (the 80% that isn't oxygen) out the turbofan engine. The stock game has it pretty close to correct. The stock "turbojet" engine (which is actually a turbofan engine, as internals clearly indicate) has a listed ISP of 2500, and an Effective Exhaust Velocity of 40,000 after the "bug" with using IntakeAir in the thrust calculation. Real-world turbojets have an ISP of 3000 (just check the Wikipedia link above), and an Effective Exhaust Velocity of 29,000. So, the stock turbojets are only 37.9% more efficient than a basic turbofan- and the difference can easily be accounted for if they are high-bypass... I always chuckle a little inside when KSP players, in the long, arduous pursuit of "realism" actually manage to create something less powerful or useful than the real-world version, simply because they feel something in the stock game is "overpowered". TL;DR The effective ISP of stock turbojets is actually correct. Real world turbofans draw on their fuel reserves as if they had an ISP of 29,000 or more- so the effective value of 40,000 in stock gameplay isn't at all out of the realm of real-world high-bypass turbofans... Regards, Northstar P.S. The mod creator might also want to check his sources for thrust values. As was suggested earlier, the dry thrust values are based on older engine designs- newer engines (the ones that aren't still classified) outperform the thrust values he nerfed the various engines down to...

Perhaps, but as it turns out on more careful investigation, for rockets, the more important parameter is their size relative to the planetary radius. Without doing any re-scaling of the rockets, you get more realistic gameplay, in terms of balance being like in real-life with a 1:6.4 scale-up, than with a 1:10 scale-up. I say *with rockets* because the velocity curves of the jet engines in the game being what they are, spaceplanes will drastically outperform their (theoretical) real-world counterparts even while rockets perform much the same as in real-life in a 1:6.4 scale-up... Regards, Northstar

Annndddd, I went and checked the Realism Overhaul release thread linked to in your signature... Stock parts are 64% of real-world scale, but your new size system lists "0.5m, 1m, 2m, 3m, etc." How is REDUCING the size of already smaller-than-reality parts bringing them up to 100% real size? If anything, you've only made the problem WORSE, by making the parts smaller than they already were (assuming the 0.625 meter parts were scaled down to 0.5 m, the 1.25 m to 1m, etc...) Regards, Northstar

The problem I can foresee with that, is it assumes you're only playing with stock parts... I play with a lot of mods that add their own fuel tanks and engines, such as KSP-Interstellar (adds a set of methane-burning engines and methane fuel tanks), NovaPunch2 (adds a whole set of larger-diameter engines and fuel tanks, as well as some unique landing legs, command modules, and reaction wheels), NearFuture mod (adds several futuristic propulsion systems, as well as solar panels, etc.), and B9 Aerospace (adds a variety of spaceplane parts and airplane/spaceplane engines) I already find stock KSP to be too limited of a sandbox, without things like In-Situ Resource Utilization (aka. "Resources"), budgets (*yet*), or missions/contracts (once again, *yet*). Therefore, Orbiter doesn't appeal to me at all. I'm leaning towards simply using a 1:6.4 scale-up when I start my next Career game (it will be a good point to add in and remove mods...) There are simply too many things which I can't imagine it having accounted for... Aside from mod parts, there's also the issue of resource production and consumption rates, for instance. Larger rockets should consume resource (for instance, electricity for ion engines- which should be consumed 2.44 times faster for an engine with a 64% larger radius) at a faster rate, yet unless they scale up the corresponding production rates as well (for instance, electricity production from solar panels would also need to increase 144%, to correspond with a 144% increase in panel area- 56.25% more across both length and width of the PV rectangles to bring them from 64% to 100% scale) And, to return to mod parts, what about mods that introduce procedural parts, but set hard limits on their maximum size- for instance StretchyTanks? (I don't know if you removed some of those limits in StretchSYB's or Procedural Parts) The more I think about it, the more a 1:6.4 scale-up sounds easier and more realistic... When I checked the thread about the 1:6.4 scale-up campaign, it said something about the alternate launchpads spawning atop 2 km high cliffs due to not spawning at normal terrain height. I would certainly not consider this to be fully "working"... Regards, Northstar

Billroy Kerman, Northstar Kerman's loyal assistant, trembled as he dialed the security code to the mission control room. Although his only role at the moment was to bring Northstar Kerman his snacks and coffee, he knew that the fate of thousands or even millions of Kerbal lives hung on the mission being carried out in this darkened room buzzing with activity. Threading around several scientists in uncharacteristically nimble gait for a Kerbal, he approached Northstar, who was deep in conversation with several engineers, and waited for the busy Kerbal to acknowledge his presence. "Yes, I know 0.4 meters per second is already a little faster than we designed the docking port for. But give it another burst of thrust to the side, or we won't come in straight and will have to try over..." rang Northstar's voice, addressing a pair of engineers. "What is it?" he said, turning towards Billroy "Ah yes, Billroy- thank you for the coffee and kalmonds. I don't know how to thank you. I needed something to keep my edge..." After nodding quickly and gratefully to Billroy, Northstar turned towards the control room's main screen, as Billroy beat a hasty retreat from the control room. Visible on the screen, a small black-and-white feed from a tiny docking camera on the front of the Amadeus' Drive Section turned slowly to the side, and then began slightly more rapidly moving forward, as Kerbal engineers dictated a tiny corrective burn of a few hundred milliseconds to better line up the docking approach with the Command Section shortly ahead. The view then slowly angled back towards the Command Section- the Drive Section having made as much of a course correction as was possible before the docking ports' two magnetic rings began to interact... "Black-and-white feeds may not make for the prettiest viewing, but they sure do add to the sense of importance", Northstar thought- though aware the feed's lack of color display was mainly in order to save on weight. A few agonizing seconds passed, as the docking rings bumped into each other and for a moment began to drift back apart- but then the magnetic forces overpowered the residual momentum, and the two vessels locked firmly into place. The KSC control room erupted in a thunderous cheer, as Kerbals celebrated the completed assembly of Kerbal-kind's most high-stakes mission to date. "We did it!" one engineer shouted. "That's right buddy!" another exclaimed, giving him a square slap on the back. The mood was ecstatic. After the earlier flub-up with the recovery of the Drive Section's launch stage, Northstar Kerman himself had supervised the docking and approach procedures, to make sure this critical aspect of the mission went according to plan. But his presence turned out not to be necessary- the engineers seemed almost instinctively to know almost exactly how to handle this mission aspect, even having not actually hard-docked two rockets since the early days of Kerb-pollo Mun landings. However, even as the triumphant Kerbals basked in their success, and gave either other Kerb-fives, Northstar Keraman ordered a status-check of the assembled vehicle, and re-allocation of the fuel supplies between the tanks, just to be sure everything was in order... Later that day, when the Kerbals had recovered the Amadeus' upper stage, files left in a folder on his desk confirmed that all readings were nominal, and the Amadeus was go for mission-initiation after a simple soft-dock (hose-based) refueling- which few engineers suspected would be at all problematic, considering how many such missions the KSC had carried out in the past... The recovery of the lower stage went smoothly as well- taking place near Lake Kerbkal in former Soviet Krussia, per a pre-arranged contract with local Krussian companies... (Kerbal national governments having recently put aside their differences and united in the Kerbal World Congress, so as to provide a united foundation for space exploration, and especially, interplanetary colonization- though not without great bickering and frequent protests by small-government and anti-government Kerb-activists everywhere...) Sitting over his file at the end of the day, Northstar Kerman thought over Kerbal politics... "I can understand the need for demonstrating to local Krussian companies that they can stand to benefit from the space program too, even as we moved the global space center to South Kafrica, but did we really need to land the Amadeus' upper stage halfway across the world, and pay for its transportation back here, just to show them we're all in this together?" Northstar thought. "I understand that Krussia is a much bigger terrestrial landing target than the small area of South Kafrica, but it still seems wasteful- and a stupid way to endanger the secrecy of Project Amadeus. What if the press gets wind of the landing?" Northstar worried to himself, massaging his forehead as had become his habit. "Oh well, I guess that's politics. Good thing I decided never to go into that field myself..." Northstar concluded. "Now where was I- ah yes, cost reports on repairing the corroded electronics on the Amadeus' reusable launch vehicle... Doesn't look too bad- I guess the salt water didn't have time to do as much damage as I feared before the recovery crews managed to fish it out..." Northstar Kerman smiled slightly to himself, and continued with his work... OOC: I hope you guys have been enjoying the storytelling. As always, I'm eager to hear who's still reading this many posts to the thread. I found many inspirations for these last couple bits- some of you might even be intrigued or surprised to learn that the bit about landing the launch vehicle off the KSC coast was partly inspired (or prescient to) my dropping my cell phone in a glass of water in real life while carrying out these missions tonight. Luckily, like the launch vehicle in my little story, I managed to quickly fish it out before it had sustained any apparent permanent damage... (or even wetted the color-changing moisture exposure indicators near the battery) And, as promised several times, at some point I will be tapering off with the story in this thread, and re-continuing it in another one. I had thought previously about doing this with the beginning of my off-world colonization efforts in earnest, but lately I've begun to lean towards the more definable and logical point of when I eventually clear this save game and start a new one with 0.24- whenever that eventually comes, and enough mods I want to keep playing with are updated to match to enable my switch... In the meantime, I hope you all continue to enjoy this thread- even if it is getting a little long... (maybe I'll break the colonization effort part of this career into a separate thread after all- if 0.24 doesn't come as soon as hoped or planned...) Regards, Northstar

Northstar Kerman rubbed his forehead yet again... "This is beginning to become a habit" he thought. Through extreme pressure on his end, the engineers had managed to agree on a final design for the Drive Section of Project Amadeus- even if it meant throwing out all discussion of adding an RCS system and hoping for the best in docking with only its NERVA engines for maneuvering. Even the launch had gone smoothly. However, the recovery of the lower stage of the reusable launch vehicle hadn't gone nearly as well... The remote control center had ended up accidentally "landing" the stage in the ocean a few kilometers east of KSC instead of on solid ground. "This is going to take WEEKS to scrub out the salt water, test the components, and replaced all the corroded parts" Northstar Kerman thought, reviewing the final mission report file on his desk... "And we don't have much time to spare..." Although the Drive Section had been launched early enough that it might be possible to repair the salt water-damaged launch stage, and still refuel the assembled mission vehicle before the asteroid impacted Kerbin, Northstar Kerman knew that plan would be pushing things a little close for comfort... What's more, due to earlier KSC budget cuts after the launch of the massive Duna Armada, there were few spare launch vehicles available on standby- majority responsibility for construction of new vehicles had been transferred to the Kerbals sent to establish off-world colonies and outposts... "The is one possibility, though" Northstar thought. "Some of the engineers have been busy upgrading the Reusable Crew Launch Vehicle a bit to extend its range." Northstar remembered. "Maybe if we swap in an older crew capsule from one of the Munar missions, and throw a spare refueling winch meant for the Amadeus fuel tanker design under construction on top, we could siphon over the needed fuel from excess capacity on the new extended tanks." It was worth a try, at least, thought Northstar Kerman, massaging his forehead again before moving aside the mission report and opening a new folder containing a planned speech for the next day. Time waits for no Kerbal, and Northstar Kerman had to begin preparing for a Kerbal secret congressional hearing the next day on the progress of Project Amadeus... OOC: I hope you guys like the (low-key) roleplaying so far... The accidental water-landing of the Amadeus' reusable launch vehicle is going to be a cause for some roleplayed delays in the mission progress. It's also going to be an excuse to try out the upgrades to the Reusable Crew Launch Vehicle I've been working on, and to time-warp forwards a few weeks if that doesn't work well enough... I look forward to reporting on more progress soon. Regards, Northstar

Northstar Kerman sat down with his lunch, reviewing the files on his desk... The upper stage of the Amadeus' reusable launch vehicle had been recovered, having landed in the foothills west of the KSC. Now it was only a matter of designing the drive section of the mission vehicle and docking it with the command section, and refueling the completed craft before it departed for Asteroid IXX-684... Meanwhile, the Minmus Spacedock had sent news that it had completed construction of a 2.3 megawatt Solar Power Transmitter, which it had been working on for several months: Although he didn't see an immediate use for the technology, Northstar Kerman was sure that it would prove invaluable in the long run... And, he still couldn't help but think of Asteroid-684 inching towards Kerbin... Regards, Northstar

Krag's Planet Factory has done a pretty decent job of implementing a second Gas Giant with Sentar: http://www.reddit.com/r/KerbalSpaceProgram/comments/1q008p/expansionkrags_planetfactorysentar_system/ I *STILL* haven't managed to get out to it in my long-running save game yet though... Regards, Northstar

Greetings! Enjoy KSP! Don't hesitate to browse around the forums blindly- there's all sorts of cool stuff on here! Take a look at the Fan Works in particular- there are a lot of cool mission reports and such there! Regards, Northstar

Northstar Kerman rubbed his forehead, hoping to ease his headache. The past seven weeks had been a madhouse of activity. After the discovery of an asteroid known only as IXX-684, or Asteroid-684 more commonly, Kerbal Space Center had become busier than he could ever remember. Desperate to avert the impact of an asteroid capable of decimating an entire metropolitan area, the Kerbal government had commissioned a secret project known as "Amadeus", though some engineers had started using the "more awesome" name of "Armadeus" for it already... Northstar Keman himself was one of the few Kerbals subject to full knowledge of the plan- which consisted of sending an enormous spacecraft assembled in orbit to the asteroid equipped with twin grappling hooks, and attempting to pull the asteroid sufficiently off-course to prevent the impact. If all went well, and the grappling concept proved successful, the vessel would also attempt to capture the asteroid in Kerbin orbit. If not... the remote-controlled vessel would back off from the asteroid, and then slam itself into the rock at high speed in the hopes of diverting it slightly off-course... Northstar was worried about the mission- his engineers had expressed concerns that the grappling hooks might prove incapable of gripping the asteroid's surface, or that the vessel might have a difficult time thrusting while towing the asteroid without spinning our of control. Further, in the case of the backup plan of a high-speed impact with the asteroid, nobody was sure how much of the velocity of the spacecraft would be transferred to the asteroid in an impact, and how much would simply dissipate into space as debris and exploding fuel mixture- if the spacecraft could even manage to hit its target... Today, however, the Kerbal Space Center had invested in the mission plan beyond the point of no return. Having manufactured the first half of the spacecraft for the mission in a record 7 weeks (faster than any other similarly complex spacecraft in Kerbal history), and also designed and built a reusable launch vehicle for the mission, the KSC had launched the first section of the mission vehicle in a magnificent launch earlier that morning, as well as recovered the first half of the reusable launch vehicle- essentially a giant reusable booster, with 37 nozzles of thrust: OOC: There are indeed 37 nozzles of thrust lifting the first stage of this launch vehicle. The main engine is a 19-nozzle giant from Novapunch. There are 6 small Novapunch liquid boosters arranged around that, and 6 dual-nozzle large Novapunch radial liquid boosters located further up the lower stage. Northstar Kerman continued to rub his forehead. It was only 36 days until Kerbin's gravity would begin to curve the asteroid towards the planet, and though earlier estimates of time until impact had been overly-pessimistic, drastically underestimating the more than week of delay that newer estimates had calculated would occur between this point and when the asteroid would actually hit the planet, time was still running out... The engineers also hadn't yet finished the second, more complex, section of the mission vehicle yet, either... They kept quarreling over questions such as whether to angle the grappling hooks inwards towards a common point of attachment on the asteroid, in line with its Center of Mass, or outwards to create the widest possible base of attachment with the asteroid; whether to rely on RCS for docking the second half of the vehicle to the command section (which contained no RCS system of its own, to speed the process of manufacturing it), and if so what to do with the RCS system after docking... (some engineers had advocated making use of a detachable RCS system that could be ejected after docking, to save weight and reduce complexity on the rest of the mission) Kerbal politicians on committees subject to knowledge of the mission flooding the KSC and manufacturing centers with an enormous influx of new money, and new engineers, to ensure the spacecraft could be designed and built before the asteroid's impact had only made the problem of design quarrels worse. Although nothing could conceivably have been accomplished in such a short time frame without massively increasing the KSC's budget and workforce, to unheard of levels, Northstar Kerman still worried that the engineers might not come to a consensus about the details of the second section of the rocket on time for the manufacturing center to finish fleshing out the frame they had already produced for the section... And Northstar Kerman doubted there was time for a second attempt if this one should fail... Scanning the folders on his desk, Northstar Kerman remembered something else equally disconcerting... The tracking station had picked up another asteroid recently: This one was not on an impact trajectory, but only an extremely close approach in roughly 169 days- but its extremely large size (a Class E asteroid) had led Kerbal scientists to worry what might happen if it should pass close to the Mun first... Should the Mun slingshot the large asteroid directly towards Kerbin, the results of the impact could be even more catastrophic than those of Asteroid-684... Fortunately, scientists estimated the probability of such a slingshot occurring at less than 1%... As Northstar Kerman's headache worsened, he decided to call it a day and catch some sleep- wondering what would happen to Kerbal-kind should Project Amadeus fail... OOC: Space is a dangerous place, apparently. Who knew?! As usual, I'm treating the asteroids in this game as if they were 10 times their reported size when it comes to impact events (as the planets are 10% real-life scale). That makes the newest asteroid 180 meters radius or more... Fortunately, it's probably not worth worrying about, as the chances of a Munar slingshot are very low. Regards, Northstar P.S. I haven't forgotten about the Eagle or my other missions to Duna. You'll be hearing about those at some point, probably after I finish assembling Project Amadeus, and eject it towards its target...

I think much of my point can be summed up as this: it's most efficient to FIRST raise your apoapsis to the desired altitude, and THEN raise your periapsis at that altitude so as to circularize; than it is to FIRST raise your apoapsis to an intermediate point between where you are (even being landed on the surface at sea level can be modeled as a 600 km x 600 km orbit around Kerbin's Center of Mass, with the normal force with the ground making up for the rotational velocity being less than the orbital velocity at that altitude, if you ignore the atmosphere for a moment...) and where you want to be, and THEN circularize at that intermiedate orbit only to have to raise your orbit again to your desired altitude. A thought question for you: which of the following do you think would be more efficient, starting from a 70 km perfectly circular orbit? (1) Performing a burn until you are in an elliptical orbit with an apoapsis at 350 km, performing another burn at 320 km (*NOT* 350 km) until your apoapsis lies at 700 km, and THEN circularizing at 700 km. (2) Performing a burn until you are in an elliptical orbit with an apoapsis at 350 km, circularizing at 350 km, and then raising your orbit AGAIN to reach 700 x 700 km. The FIRST of these is an excellent analogy for a direct launch to a higher orbit that I am advocating, the SECOND of these is an excellent analogy for the "circularize first" pattern of reaching higher orbits that you are espousing. It can be mathematically shown that the first of these requires slightly less Delta-V. Regards, Northstar

Also, it makes almost no difference whether you perfectly circularize at 70 (or 75 km), and then burn at another point of the exactly circular orbit until your apoapsis is 250 km; or whether you were to burn at apoapsis of a sub-orbital trajectory, until you reached a perfectly circular orbit, and then continue burning at the same point (assume either an infinite TWR, or that you wait until your orbit takes you back to the exact same point- the two are essentially the same) until your apoapsis is at 250 km. Either one is mathematically identical. The real deviations between the two are due to real-world limits due to TWR, and make little real difference in the discussion here. A continuous burn at 70 km, to transform that point from the apoapsis of a sub-orbital trajectory to the periapsis of an elliptical orbit with an apoapsis at 250 km; is less efficient than an ascent at which you continuously burn your engines in the upper atmosphere until your apoapsis lies at 250 km, and then coast to that point, and circularize there. I would like to point out that I *NEVER* said you are "closer to periapsis at apoapsis". I said you are closer to periapsis of a sub-orbital trajectory at 50 km than at 70 km. This assumed you could understand the point that sub-orbital trajectories can be modelled as elliptical orbits. Real deviations between the two are due to TWR limitations of vessels, steering losses, and drag. Once again, try the one-part vs. 2-part ascent to 100 km. You should see the differences in fuel consumption more clearly there... Regards, Northstar

I'm not understanding how you're getting your own language so convoluted. Or mine. What I said was very clear. In a sub-orbital trajectory to 70 km, your apoapsis is at 70 km. You can model a sub-orbital trajectory as a highly elliptical orbit, if you forget the presence of the atmosphere for a second (it ceases to have any truly significant effect by the altitudes we are discussing), and forget about the terrain (model the planet as a point-mass at its Center of Mass- which is basically what KSP does- adding a collision mesh at the planetary radius). Your "periapsis" from a mathematical standpoint, then lies within the planet itself. It is *more efficient* to burn before you reach 70 km (at 50 km) in order to set a sub-orbital trajectory with an apoapsis at 250 km, and then circularize at 250 km, than to first circularize, and then raise your apoapsis at 250 km. For simplicity's sake, I assume that if you have an apoapsis at 70 km, you will burn until this point is your periapsis (and just above the atmosphere) and your new apoapsis is 71 or 72 km on the opposite side of the planet. It's almost exactly the same mathematically as if you set a sub-orbital trajectory at 71 or 72 km, and then raise your periapsis to 70 km in your circularization burn, but is easier to imagine/visualize. Once gain, you are moving faster at 50 km when in a sub-orbital (ballistic) trajectory with an apoapsis at 70 or 72 km, than you are when you reach 70 or 72 km. While you are much closer to apoapsis than to "periapsis" (which is actually a mathematical point close to the core of the planet, which you would crash long before reaching) at 50 km, you are still closer to the imaginary (negative-altitude) periapsis than you will be at 70 km. It is a more efficient point to raise your apoapsis further than at 70 km. What I've tried to point out repeatedly, and you don't seem to understand, is that first circularizing, and then raising your apoapsis, is exactly the same mathematically as setting a highly elliptical orbit, and then burning at the apoapsis of that elliptical orbit until that altitude is your new periapsis, and continuing to burn at that altitude until your apoapsis is even higher. So actually, you ARE "burning at apoapsis to raise you apoapsis", which is inefficient. This is why I repeatedly state you will save Delta-V going for a straight launch to a higher orbit, and then circularizing when your reach apoapsis at the altitude of that higher orbit. Regards, Northstar

It's not really a standard part of the game, as I understand it. I'll stick with KSP, rather than wasting more hardisk space for such a restricted and unimaginative game, thank you very much... I don't mean to be abrasive- but I don't even see why anybody would actually *like* Orbiter. The game has nothing truly creative about it- it's just an attempt to re-create history exactly as it happened more or less... (with all the mistakes we've made in real life) The system for designing *new* rockets and mission is vastly inferior to KSP. Regards, Northstar

Deadly Re-entry has nothing to do with actually having a realistic planet. It does implement a re-entry heat system, but that's an entirely separate issue... I wanted to barf after watching the first video. Lorenzo clearly doesn't remember how to play KSP anymore (SRB's in the upper stages, seriously?), and it's extremely annoying... I was aware of the 1:6.4 re-scale config for RSS (I mentioned it in the OP), but not his campaign system. Once again, not really relevant to having an actually realistic planet though. If he can get the alternative launchpads working, however, I might still look into it so as to set up permanent alternative launch sites in the mountains and at different latitudes, so as to allow high-altitude launches and launches directly into inclined orbits... Once again, though, his campaign system is not really relevant to the thread topic... Regards, Northstar

I prefer KSP's snap-together rocket building- I just want it to be a bit more realistic. As I understand it, Orbiter only allows you to re-create real life missions... I have no interest in a game that so limits my creativity... Regards, Northstar

I also feel the need to more carefully address these parts of your post in particular: Yes, but you're *closer* to periapsis than when you're at apoapsis. The worst possible place to raise your apoapsis is from another apoapsis, by burning there until it becomes your new periapsis, as the average speed you are moving during your burn (which increases throughout the burn) is the lowest there. If you burn closer to periapsis, you will have a more fuel-efficient increase in your apoapsis... This increases the closer you are to periapsis, until you reach the ideal point of burning *at* periapsis... (I need to double-check whether you want to burn at prograde, or parallel to the horizon, or something in-between at a point that is between apoapsis and periapsis, however... I remember the answer not being 100% intuitive, and may have incorrectly stated it before when I said to simply burn prograde...) As I stated before, in the post to which you were responding, this point only becomes your periapsis through an apoapsis-burn. This is less efficient than burning at a point closer to your original periapsis... You CANNOT discuss two sections of a continuous burn separately like that, and ignore only one portion, focusing on the other. Yes, your speed is higher AFTER the circularization is complete- but that is already well into your burn to raise your apoapsis to 250 km. The average speed at which you are moving during that burn, starting from the beginning of your circularization burn, and ending at the end of your burn when your apoapsis has reached 250 km, is LESS than during a burn started at 50km in a sub-orbital trajectory, that raises your apoapsis to 250 km. Even if you actually perform the burn in two parts, by first circularizing, and then raising the apoapsis at the new periapsis the next orbit around, the 2-part burn can be treated the same mathematically as an idealized (instantaneous) 1-part burn at the apoapsis of your sub-orbital trajectory. And, the average speed of that burn is less than in an idealized (instantaneous) burn at 50 km to raise your apoapsis to 250 km. At least we can agree on this. I've tested once or twice going to 750 km or even higher, and the effects didn't seem to change. The problem with that experiement, however, is that the transfer orbit from a 70 km circular orbit to a 750 km orbit, is highly elliptical- so there is *VERY LITTLE* difference between its eccentricity and that of a direct transfer to 750 km. Therefore, Delta-V savings, while not decreasing in absolute size, become relatively much smaller- and thus *MUCH* harder to actually measure... The *BETTER* experiment is actually to compare a direct launch to 100 km vs. a 2-part launch to 100 km (to 70 km and then a transfer to 100 km), where the fuel-savings of the direct launch should be MUCH more noticeable. Try performing *that* experiment a few times, and see how your results differ... Regards, Northstar

There *might* be some differences in the ascent profiles of our rockets, even when circularizing at the same points. Don't forget that the MechJeb default launch pattern is usually not the most efficient flight plan to get your rocket to orbit. While it works well as a general approximation, you need to adjust your flight path based on factors like launchpad TWR and staging, which cause you ideal flight plan to deviate from the default/generalized MechJeb plan... I've repeatedly performed these experiments pre-0.23.5 The result was always the same- the direct launch saved fuel after I figured out the most fuel-optimal flight pattern for the direct launch... Try tweaking the flight pattern on the direct launch to 250 km, or even performing it manually using the MechJeb ASAS (in "Surface Mode"), to see if you can't out-perform your 2-part launch with a bit of optimization. My bet is, you can (I could). It might also be helpful to see screenshots, with a lot of emphasis on the gravity-turn portion, to see how each ascent could be improved. Also, what mods were you running during your ascent? Running FAR, for instance, changes the relationship between a direct launch and a 2-part launch, by making drag less of an issue with properly-designed rockets... Regards, Northstar

But if you find a way to re-use or recycle all the mass you get to orbit, then the equations become almost identical... It's a useful simplification to find the way to get a rocket to orbit that costs the least Delta-V, rather than the least fuel... v That is part of the point, that no space-grade jet engines currently exist. Therefore, developing them requires an extensive R&D cycle, adding to their cost- whereas rocket engines have already been in use for over 50 years to carry payloads to orbit. Therefore, the most realistic cost-comparison really would be between a surplus rocket engine and a state-of-the-art jet engine, as this best mimics the relationship between a state-of-the-art rocket engine and a only-theoretical jet engine in terms of cost... The number of moving parts is indeed a major factor in manufacturing and design cost. It is true, it is not the only factor, but it is one of the main reasons jet engines cost so much more than rocket engines... Regards, Northstar