Starman4308

Launched my first 6.4x Apollo-like mission to the Mun: it's presently sitting in low Mun orbit. The intent is to abuse the science lab attached to the CM to store a large number of experiments; while I could probably milk more out with a reusable lander and a refueler in orbit, I decided overly-extensive milking of Munar biomes just isn't very fun. Launcher mass was ~680 tonnes; small hints like "in low Lunar orbit: injection stage still has a few drops of hydrogen left" suggests that probably could have been trimmed down noticeably.

There's no config for the Terrier. Is there any post I can look at for the logic/conventions of how to write configs for the fuel tanks (whether it's always X units of LF/O converts to Y liters of capacity or if non-linear functions are used, etc)? It can't be too hard for me to write a config. EDIT: Also, was the PB-ION intended to have 148 E/s electrical consumption? That's kind of 8.2 Gigantor XLs' worth of electrical consumption, and I'm wondering if it got changed to RF/RO's electricity units, and not changed back in this config.

I'm not sure if you intended to have compatibility for them, but at least some parts in Modular Rocket Systems aren't set up. The fuel tanks seem hardcoded to LF/O, and it seems almost random whether an engine is configurable.

That is very much not what he's asking for. He's asking for help with something he can launch early in career. This means no wings, no struts, no solar panels. I whipped up something which should get you to the Mun with four Science Jrs. and four goo pods: it's a little bit prone to rotation during the first stage, and it comes down hard back on Kerbin (unless you add a couple radial parachutes* or use a lot of thrust from the LV-909), but it's got an excess of delta-V. Most of the engines are LV-T30s, with one LV-909 for the last stage. I would recommend tweaking the RT-10's thrust to around 75-80%, and removing all the monopropellant from the command pod. It requires only basic rocketry, stability (for the radial decouplers), survivability (for the LV-909 and landing legs), and science tech (for the Science Jrs). If you don't have science tech yet, probably go with the earlier design, since this was based around getting 4 goo pods and 4 Science Jrs to the Mun and back with an excess of delta-V. *Two radial parachutes remove ~300 m/s delta-V, but would still leave you a lot of margin for error. Also, the batteries also require Science Tech; they're physics-less, which means they won't affect rocket performance, and will give you a little more margin for error, because you don't get solar panels for a while, and before then, your only source of electricity is liquid engines (NOT including the LV-909, which generates no electricity). EDIT: In general, you want a wide landing base so your lander doesn't tip: I accomplished that by placing the legs on radially-attached Science Jrs. The specifics of staging are a bit of a fine art; KER and MechJeb can help enormously by letting you see what the delta-V and TWR are for each stage as you build the thing. This delta-V map helps you figure out what you need. Beyond that, the biggest piece of advice is to figure out what you need, and try to trim every kilogram of payload that you don't absolutely need (for example, the monopropellant, which I forgot to remove from this).

A, it will inevitably be inaccurate for long reentries, because reentry is inherently chaotic (highly sensitive to minor things, and error grows exponentially with time), so more error is to be expected with long reentry. B, are you using wings with stock aerodynamics? Trajectories will not account for stock wings. C, just to check: are you going in nose-first or tail-first? 0 degrees means a nose-first reentry, generally valid for spaceplanes but invalid for capsules. D, are you using Deadly Reentry? Trajectories won't account for loss of ablative heatshield material. E, are you using any RCS stabilization? Trajectories won't account for use of RCS fuel.

Well, there's a stock "gravity turn" and then there's real gravity turns. What you do in stock is gradually tip over eastwards. In the absence of atmosphere, you want the absolute minimum amount of vertical thrust necessary to avoid uncomfortable encounters with terrain: you want to start going horizontal as much as possible from the moment of liftoff. This practice minimizes gravity drag (loss of dV to gravity). In the presence of stock souposphere, though, sea-level atmosphere is going to kill your velocity quickly (aero drag). As such, you want to burn vertical to get out of the thickest of the soup before starting your eastwards turn. This is what MechJeb is calibrated for: a pitch profile designed to balance aero and gravity drag in a stock drag environment. It has nothing to do with aerodynamic stresses or AoA, because stock aerodynamics acts equally an all parts and does not model body lift. A real gravity turn can only really be done in FAR/NEAR. In these mods, you wait until you're going ~60-100 m/s (depending on rocket TWR profile), tip over 2-5 degrees east, wait for your prograde marker to catch up, and then say "Look Ma, no hands!". If CoL is properly behind CoM and your rocket is pointed reasonably close to prograde, aerodynamic stability will tend to keep your rocket pointed dead-prograde all the way through until you hit upper atmosphere. You need to do this (possibly plus or minus a few gentle control inputs), because any violent movements away from prograde will cause your rocket to flip from aerodynamic instability, and if you start your gravity turn too late, you will, A, run into difficulties trying to turn at high velocity, and B, waste lots of dV going upwards. Once you've passed max-Q (maximum aerodynamic stress) and are in upper atmosphere, you can start to have your own ideas about what the proper orientation is. I would suggest trying to keep tAp (time to apoapsis) around 10-20s, which will describe a gentle ascent which is mostly going horizontal, minimizing gravity drag while slowly getting you out of atmosphere. This often has the advantage of keeping you in a good orientation to take advantage of body lift*, though that is dependent on your current stage's TWR and how close you are to orbital velocity. *Go fast enough, and even a giant tube of rocket fuel gets aerodynamic lift in FAR/real-world physics.

You probably don't need as many legs as you think, particularly if you still have the engines going at landing. Alternately, you could try some unholy contraption of girders, but I still think your solution is going to be "just get rid of some excess legs". You might also consider widening your landing base to keep it from tipping over on slopes: tall and skinny is a good way to get a lander tipped over. Many of my landers have the legs on an onion stage: I'll have 4-6 tanks on radial decouplers, with fuel lines leading in, such that I can rid myself of both the fuel tanks and the landing legs on ascent. Not guaranteed to function for reusable landers. Use at your own risk.

Another suggestion is to try to immediately match the plane of Minmus's orbit. What you do is wait until you can draw a line straight out from the space center which crosses Minmus's orbit (you are directly under the orbit), and launch six degrees away from east (either north or south, depending on whether you are under the ascending or descending node). If you do it right, you wind up in almost the right inclination, which minimizes the amount of effort you spend on the plane change. The easy way to do it from there is to create a node at ascending/descending node to exactly match planes, and then do your Hohmann transfer, but the more efficient way is usually to transfer first, match inclinations second. The reason that works is that plane changes are easiest at low velocity, so if you have an ascending/descending node halfway out in the transfer, when your rocket is at a much lower velocity than LKO, your plane change will be more efficient. The only exception is if your AN/DN will be immediately after the transfer, when you still have a lot of velocity from the transfer. EDIT: An extreme, illustrative example of plane changes: I once launched a rocket into Munar orbit, but accidentally sent it into the opposite direction from the rest of my orbital flotilla. A direct 180 degree plane change in low Mun orbit (reversing the orbit) would have cost more dV than I had remaining. However, I discovered that a bi-elliptic transfer would work: I raised apoapsis almost to Munar escape, reversed my orbit at apoapsis, and returned to low Munar orbit on a dV budget which would have been just barely enough to cancel my velocity in low Mun orbit.

I'm not so certain on LH2/LOX first stages. The low density of LH2 leads to physically enormous fuel tanks, which poses structural/aerodynamic difficulties. LH2/LOX sea-level Isp and TWR also tends to be very poor to mediocre; it might partly be a function of the engines I'm looking at for reference (Rocketdyne J-2, Space Shuttle Main Engines), but LH2/LOX mostly shines once you get into mid-upper atmosphere. Plus, for first stages, efficiency does not really matter. If two designs will get an identical payload to the same place, and one costs 5% less, it doesn't matter if it weighs 10x more; you haven't staged yet, so the mass isn't propagating down. Now, that would make a terrible second stage, because your first stage would have to launch 10x the payload, but for first stages, the primary considerations are TWR, cost, aerodynamics, recoverability, and stability.

Were you using stock parachutes? The RealChute config for stock parachutes is presently bugged, and will be fixed in the next update. Until then, delete the stock config file from RealChute/Module Manager, or never use stock chutes.

VAB or SPH, go to action groups tab, click on a number you'd like to toggle them to, and then start clicking your panels and set them to be toggled by that action group.

It automatically launches 32-bit, but the 64-bit client is in your Kerbal Space Program folder (under Steam/steamapps/common/Kerbal Space Program if I remember right)

The service module and fuselage tank types are pressurized, which lets you put hypergolic fuels (Aerozine 50, MMH, etc) in them*. Cryogenic and cryo balloon tanks have reduced boiloff of cryogenic fuels such as liquid hydrogen, at a mass penalty. Balloon tanks are much lighter than normal tanks, but with less structural strength. *Only necessary if using Engine Ignitor. Otherwise, use whatever ridiculous tank type you want. First off, these questions really should be asked in the Engine Ignitor thread, not the Real Fuels thread. You need a Kerbal to EVA, right-click the box, move to the engine, right-click, and add an ignitor. Also, you may be running into lag issues for large rockets with a large number of tanks and engines: something about Engine Ignitor's calculations takes a huge amount of time with RealFuels. As I understand (I deleted Engine Ignitor for aforementioned lag issues), ullage is to settle liquid fuels to the bottom of the tank before ignition so they properly flow to the engine without air bubbles. Not sure what to say. Kerosene-LOX is a favorite for first stages. It tends to produce good sea-level thrust with reasonable Isp. LH2/LOX is the most efficient chemical rocket fuel by miles, but has a couple problems. First off, it is very low-density: you need huge fuel tanks to store it. It has issues with low sea-level thrust and Isp, and is cryogenic: LH2 boils off even at -200C (LOX does so at -180C), so cannot be stored long. Hypergolic fuels like Aerozine50/NTO can be stored basically indefinitely, but require pressurized fuel tanks (service module or fuselage), and generally have relatively mediocre thrust/Isp performance. Moar staging. If you have payload issues, do in-space assembly, potentially incorporating nuclear rockets (I would suggest liquid ammonia if you are concerned about boil-off: it has a very high boiling point). Also, strongly consider a Mars rendezvous mission profile (lander rendezvous with return stage in orbit, so you don't have to lug the return fuel down to the ground and back up).

I've done some pseudo-asparagus off SRBs by slapping a fuel can or two onto the top of an SRB and using that to fuel the inner liquid stage. I am, however, also confused by what DrMonte means.

Your kinetic energy relative to Earth's gravitational field would increase in a rather disproportionate fashion compared to the chemical energy you used pushing yourself off that asteroid. Your kinetic energy relative to what you pushed off of would be proportional to chemical energy spent*. The reason overall energy is conserved, even in Earth's reference frame, is that, despite giving yourself a huge kinetic energy boost, you also removed a lot of the asteroid's kinetic energy relative to Earth's gravitational field. *And, with a rocket, you are pushing off of your propellant, which conveniently travels with you right up until you burn it. Oberth comes out of the fact that kinetic energy is not linearly dependent on velocity: KE = 1/2*m*v^2. As such, a given change in velocity gives you much more KE when you are already traveling fast.

Well, you can numerically integrate several differential equations describing thrust, drag, and aerodynamic lift* to achieve approximate answers, though they are dependent on many variables, such as what pitch profile you want. There's several programs out there which help you do that: one of my favorites is called Kerbal Space Program. To be helpful: what MajorThomas said. MechJeb will generally fly an okay gravity turn; you can probably optimize it, but it gives you a rough idea of what you should be doing (disclaimer: not valid for FAR/NEAR aerodynamics, which are much less forgiving of large pitch angles). *Using realistic aerodynamics, as opposed to the stock souposphere. If you're wondering: the programs NASA uses are probably very similar to KSP's physics engine, except with much more realistic equations, and much more boring interfaces.

No. Rockets operate on momentum and force (velocity and acceleration, once you divide the mass out). The Tsiolkovsky equation is dV = Gm*Isp*ln(full/empty mass): they can change their velocity on a function dependent on mass ratio and engine efficiency. At no point does kinetic energy factor into rocket delta-V. Kinetic energy is a consequence, not a determining factor. The size of your orbit is dependent on kinetic energy and the strength of the gravitational field. The whole point of the Oberth effect is that you get more kinetic energy if you are already traveling at a high speed: going from 0-100 m/s gives you 5000 J/kg of specific kinetic energy. Going from 1000-1100 m/s, an identical expenditure of delta-V (100 m/s), gives you 105,000 J/kg of specific kinetic energy. Despite costing your rocket an identical amount of delta-V, the second maneuver has given you far more kinetic energy. Oberth won't change how much delta-V you get. Oberth will change how much you can get out of your delta-V. A Jool transfer manuever node will use a certain amount of delta-V. You will always need to spend a bit more delta-V than displayed, however, because that maneuver node assumes an instantaneous burn, taking 100% advantage of the Oberth effect. Since real rockets cannot change velocity instantaneously, they cannot take 100% advantage of the Oberth effect, and will have to perform a correction maneuver to get them back on course.

Please read the "How to get help" thread, stickied at the top of this forum, and linked for your convenience. If we don't even know what mods you have, we can't begin to help you, and log files help enormously in figuring out what's throwing errors.

It's a mod. The original 6.4x Kerbin is a config for NathanKell's Real Solar System. There is also the WIP 64k project by Paul Kingtiger which seeks to wrap 6.4x Kerbin together with config files for various mods in more cohesive ways, so you don't have to deal with as much hassle installing 6.4x Kerbin, particularly when it comes to compatibility with mods like Astronomer's Visual Pack. Just, do us all a favor, and read the instructions before installing it either way. Also, if you use the 64k installation, I'd set Kerbin's rotationPeriod to 64800 (18 hours), because with the standard 12-hour day Paul used, you get too much of a boost from launching east. Also, I love the use of RealFuels (and the stockalike config, plus FAR) for 6.4x: these combined get you "bigger Kerbin" without requiring absurdly oversized rockets.

Please do not post in old, dead threads unless you have something specific and significant to contribute. Another "well, it works for me" post does not help anything. Everybody knows Windows x64 works for some people, but because it works for some people does not mean that x64 is in general stable, or that modders will stop disabling their mods for x64. To once again restate what has been stated a million times: x64 is unstable for enough players to warrant an "unstable" tag, some of those players send modders bogus bug reports which boil down to x64 being unstable*, x64's instability is due to some issue in the Windows distribution of Unity 64-bit, and there will basically be no fix until the release of a Unity version which fixes the 64-bit instability. *In an ideal world, people would realize their issue stemmed from x64 being unstable, but that hasn't stopped people from complaining to modders about crashes which have nothing to do with the mod.

It might help to use KW Rocketry or some other part pack to build giant boosters to get your giant space station into space. Possibly Modular Rocket Systems, which I think might have a 3.75m docking port. Other than that, you might want to look into mods which add lighting, and various station part packs listed in the mod library. I think KSP Interstellar also has cool-looking stuff.

At some point, my morbid curiosity will have me trawling through the DRE and RealChute threads to find out how many people have complained about parachutes burning up. Bonus points for posting screenshots with visible reentry effects. Better not make it a drinking game, though. Pointing exactly retrograde isn't always the best choice, though. If you've got FAR, you can give yourself a few degrees of pitch above retrograde for a lifting effect, keeping you in high atmosphere longer, bleeding off speed in the Goldilocks drag zone. It does increase risk of exposing a part to reentry burn: if you have asymmetric parts (particularly the Pegasus I ladders*), you will often want to rotate the capsule so that the bulky parts are on the bottom, since they will be more shielded from reentry burn that way. *RCS thrusters are also frequent offenders, but since they're generally radially symmetric, there's no real solution to that, other than making sure your heatshield gives you enough of a shadow to hide the RCS, and not having too extreme of pitch. Also, what I call the "Goldilocks drag zone" is that region of atmosphere which will give you substantial drag in a short amount of time, without immediately stripping your heatshield off. Spend too long in really high atmosphere, and you lose speed too slowly: you will start heading for low atmosphere without shedding much horizontal velocity. Go in too steep, and you go straight to lower atmosphere, do not pass Go, do not collect $200.

What are you looking for in a space station? A refueling stop? Something to expand the science part of the game? Your wildest sci-fi shipyard fantasy? A rendezvous point for reusable interplanetary vehicles? Something to look gigantic and impressive?

RealFuels changes fuel masses to be much more realistic, and the engine configs (I personally love Raptor's stockalike config) usually tweak fuel tank and engine masses to be much more realistic. As such, you will get a lot more delta-V out of each stage and out of each tonne of rocket. It's still not enough to bring rocket sizes down to match stock, but it helps out with some of the nasty exponential part. Just do be aware that boiloff of cryogenic fuels (like liquid hydrogen) is a thing in this mod. The 6.4x config (either Raptor's original, mentioned in the OP, or Paul Kingtiger's in-development integrated install) reduces the difficulty a bit, although you don't get real-world planets. Procedural Parts lets you make SRBs and fuel tanks of arbitrary size: my only gripe with it right now is that the tanks are ridiculously cheap, having been scaled for Realism Overhaul and not for anything resembling normal career mode games. I think that might be getting worked on, but for now, just send sacrificial rockets into the ocean if you want to compensate for the tanks' low cost. KW Rocketry, and possibly other part packs like NovaPunch, include 5m engines and some truly spectacular SRBs. I know KW is RealFuels-compatible. FAR, if you can deal with the difficulties of realistic aerodynamics, makes ascent (and DRE reentries) much easier by removing the souposphere: you'll see probably 1-2 km/s delta-V shaved off launch costs. TweakScale can arbitrarily scale stuff up, but I have heard it conflicts with many mods. I personally dislike Realism Overhaul for throwing out the stock engines and rescaling too much, as well as making career mode very difficult to have fun with, but I suppose it's alright if you enjoy trying to replicate real-world missions, and deal with a few things KSP leaves out (like how weak real reaction wheels are). Just be aware that RO changes a lot of gameplay at once. I think it might also have been shut down for some reason.

Leave them up at the top, safely behind the cylinder of protection offered by the heatshield. Make sure you have a heat shield. Also make sure you are not deploying your parachutes into superheated reentry plasma. Nylon does not like 2000 degree reentry plasma. Wait until you're around 200-250 m/s before popping chutes: Mach 1 is about 330 m/s, and supersonic velocities will eat your chutes.