OhioBob

Absolutely realistic. I used real life formulas to compute what the ISPs would be if we decreased the expansion ratio of the nozzles. I didn't want this mod to be a means to cheat fate by using fake science. The science is real and the numbers are realistic. It's not cheating to do what any competent engineer and space agency would do. Normally a nozzle is designed so that the pressure of the exhaust gas at the nozzle exit is equal to the ambient air pressure. Of course when an engine must operate over a ranges of pressures, such as a first stage booster, compromises must be made. A first stage engine might be expanded until its exit pressure is somewhere around 0.5 to 1 atmosphere. The nozzles of middle stage engines, or sustainer engines, are expanded further to lower the exit pressure to the ambient air pressure expected in the middle to upper atmosphere. For engines that are to operate in space, very large expansion ratios are used to lower the exit pressure as close to zero as is practical. Increasing the expansion ratio improves an engine's performance in a vacuum, but decreases its performance at high ambient pressures. This is why we generally have two classes of engines - those with small expansion ratios that have good sea level ISP but relatively poor vacuum ISP, and those with large expansion ratios that have good vacuum ISP but poor sea level ISP. On Eve we want to go in the direction of lowering the expansion ratio. Taking an engine designed for sea level on Kerbin and using it on Eve is just like taking an engine designed for use in a vacuum and putting it on the first stage of one of our launch vehicles. We've learned from experience that we don't do that. Each engine has its proper application, and for Eve we need engines designed for the high atmospheric pressures. For our Eve engines, we want to decrease the expansion ratio until the nozzle exit pressure approaches the atmospheric pressure near the surface of Eve. This will give us the best ISP we can get in that environment. Of course, the downside is that we lower the ISP we'll obtain when we get to the upper atmosphere; however, by then we'll have jettisoned our first stages engines and switched to something that will perform better in the thinner air. To launch from the surface of Eve, we want engines that will give their best performance at liftoff when the rocket is heavily burdened with a full fuel load. For this mod, I computed what the ISP of the stock engines would be if we redesigned the nozzles to give us an exit pressure of 4.2 atmospheres. This is the atmospheric pressure on Eve at an altitude of 1000 meters. These engines are designed specifically for launches from low altitudes. If you plan to land on a mountain top, then you are likely better off just using the stock engines.

Alpheratz

My experience is similar. I installed Real Solar System and gradually started to turn up the realism with the addition of mods. I eventually reached a point where it stopped being fun because there were too many details to pay attention to, so I ended up backing it down to the previous level. I never made it to full-blown RO.

Eve Optimized Engines version 3.0.2 Eve Optimized Engines provides low expansion ratio variants of six of the game's most popular engines - Swivel, Reliant, Spark, Thud, Skipper and Mainsail. These variants provide greatly improved high ambient pressure performance, which comes by sacrificing low-pressure performance. When operating on Kerbin or in space, stick with the stock engines. But when launching from the surface of Eve, the modified engines provide good first stage power and performance. Download from GitHub Requirements ModuleManager B9 Part Switch Optional An optional config is provided that decreases nozzle expansion ratios further for use on planets with even higher atmospheric pressures. It is designed for use with mods such as Realistic Atmospheres or JNSQ, which increase Eve's sea level pressure to 10 atm. Installation Instructions 1. Download Eve Optimized Engines v3.0.2. 2. Copy from [Download]\GameData\ to [KSP]\GameData\ the folder EveEngines and all its contents. Older Versions Eve Optimized Engines v3.0.2 works only in KSP 1.12.2+. For KSP versions 1.9 to 1.12.1, use v3.0.1. For KSP 1.8.1 and earlier, use v2.0.6. Eve Optimized Variants LV-T45 “Swivel” Liquid Fuel Engine Maximum thrust: 179 kN (Vac.), 172 kN (ASL), 145 kN (Eve SL) Specific impulse: 266 s (Vac.), 256 s (ASL), 216 s (Eve SL) LV-T30 “Reliant” Liquid Fuel Engine Maximum thrust: 205 kN (Vac.), 197 kN (ASL), 166 kN (Eve SL) Specific impulse: 265 s (Vac.), 254 s (ASL), 214 s (Eve SL) 48-7S “Spark” Liquid Fuel Engine Maximum thrust: 17 kN (Vac.), 17 kN (ASL), 14 kN (Eve SL) Specific impulse: 274 s (Vac.), 265 s (ASL), 228 s (Eve SL) Mk-55 “Thud” Liquid Fuel Engine Maximum thrust: 106 kN (Vac.), 102 kN (ASL), 87 kN (Eve SL) Specific impulse: 269 s (Vac.), 260 s (ASL), 222 s (Eve SL) RE-I5 “Skipper” Liquid Fuel Engine Maximum thrust: 567 kN (Vac.), 550 kN (ASL), 479 kN (Eve SL) Specific impulse: 279 s (Vac.), 271 s (ASL), 236 s (Eve SL) RE-M3 “Mainsail” Liquid Fuel Engine Maximum thrust: 1350 kN (Vac.), 1311 kN (ASL), 1147 kN (Eve SL) Specific impulse: 279 s (Vac.), 271 s (ASL), 236 s (Eve SL)

Small Magellanic Cloud

Nancy

You might try giving these suggestions a try... Ferram on Ascent Profile and TWR

Since starting this thread, I've at least figured out how to make minor changes to the graphics. So far all I've done is change the "45" stenciled on the side of the LV-T45 to read "55" on the side of the LV-T55. Not much, but I know now that I have some tools to work with. I should be able to change the paint color on the engines so we have at least that to differentiate them. I don't feel comfortable trying to edit anything more than the color. It is not a big difference, but it is enough that I feel that I can release the mod. If anyone what's to volunteer additional help, I'll accept it, but I think I can get by (minimally) with what I have.

Although I haven’t performed many Eve launches, I’ve always found it frustrating that I have to use engines, designed for use on Kerbin, that have really lousy performance on Eve. There is nothing mysterious about designing an engine that will give good performance on Eve. It just requires a low expansion ratio nozzle that is optimized for the high ambient pressure. No space agency would ever take a Kerbin-optimized engine and settle for using it on Eve. They would design engines specific to Eve’s environment. My idea is to mod a few engines for Eve landing/return missions. I’ve actually done this already, to a point. I took three of the game’s stock engines – Swivel, Skipper and Mainsail – made copies, and then edited the configuration files to turn them into Eve-optimized versions of the stock engines. It is already a fully functioning mod, but, since the engines are just copies of the stock engines, they look identical to the original. I’m not a modder. I can edit a configuration file, but I have no idea how to go about changing or creating graphics. I’d like to release this as a mod, but it would be pretty lame to do so without some change in the graphics to differentiate the engines. I’m requesting help from any modder who’d be willing to collaborate with me by making the graphics changes. Since the mod engines are supposed to be variants of the stock engines, there are only minor differences. The only real change would be in the size of the nozzle (the mod nozzle would be shorter with a smaller exit diameter). Some color changes would also make the engines easier to distinguish, such as changing the orange paint on the Skipper and Mainsail engines to some other color (perhaps purple). Just to show you what I have so far, here are the names, descriptions, and stats for the modded engines: LV-T55 "Abel" Liquid Fuel Engine The LV-T55 engine is a variant of the popular LV-T45 engine. It is furnished with a low expansion nozzle to optimize its performance in high ambient pressure environments. The engineers claim it will work even on Eve. Maximum Thrust: 171.25 kN (Vac.), 165.625 kN (ASL), 142.5 kN (Eve SL) Specific impulse: 274 s (Vac.), 265 s (ASL), 228 s (Eve SL) RE-I5-1 "Viper" Liquid Fuel Engine The Viper is a low expansion ratio version of the highly popular and versatile Skipper engine. While outperformed by the Skipper in most environments, the Viper is really at home on the planet Eve. In Eve's thick lower atmosphere, the Viper provides good mid-power performance. Maximum Thrust: 568.75 kN (Vac.), 550.469 kN (ASL), 477.344 kN (Eve SL) Specific impulse: 280 s (Vac.), 271 s (ASL), 235 s (Eve SL) RE-M3-1 "Cobra" Liquid Engine The Cobra is a low expansion ratio version of the powerful Mainsail engine. Like its smaller sibling, the Viper, the Cobra is designed specifically for use on Eve. It has both the high-power and performance to be used as an Eve heavy lifter. At least that's what the engineers say. Maximum Thrust: 1350 kN (Vac.), 1311.29 kN (ASL), 1146.77 kN (Eve SL) Specific impulse: 279 s (Vac.), 271 s (ASL), 237 s (Eve SL) If anyone is willing to help me out, please reply. If any modder wants to take this idea and develop a series of all new Eve-optimized engines, I have no objection. I’m willing to help out with whatever part I can do. If someone has already written a mod for something like this, then I apologize for stealing your idea. If such a mod exists, can somebody please direct me to it?

The specific impulse of SRBs is terrible at high atmospheric pressures. The best is the Kickback, Pressure (atm) Specific Impulse 0 220 1 195 2 165 3 133 4 100 5 67 6 33 7 0 From most places on the surface of Eve, the Kickback can't even lift its own weight.

Ulan Bator

I really don't like the idea of going interstellar with hyperdrives, etc. That seems a little too sci-fi to me. However, my thought is perhaps Kerbol could be made into a binary star system with a realtively nearby companion star (the companion would be just far enough away that both stars could maintain stable planetary systems). Reaching the companion star, and discovering its family of planets, could be done with some advanced technology but without getting real sci-fi.

Apollonia (an asteroid)

Halifax

Since you already used that one, there shouldn't be any problem reusing this one... Xanthippe

Nagasaki

KER does include orbital period, though I don't believe it shows it by default. You have to customize the display. Select the Orbital display and click the Edit button. You'll see a list of "Available" data and a list of "Installed" data. Find "Orbital Period" in the available list and click "Install".

Are you sure that was dV and not just velocity? Earth escape velocity is about 11 km/s, so it makes sense that someone would accelerate their lunar impactor to 11 km/s. However, adding in for gravity and drag losses, it should take a dV of at least 12.5 km/s or so to make it from the ground to the moon.

I keep the throttle at 100% all the way. Pre-1.0, it was common to throttle back during ascent to keep the rocket from exceeding terminal velocity. However, terminal velocity is now high enough that it is almost impossible to reach it unless you have insanely high TWR. Therefore there is no reason to throttle back unless you are experiencing control problems, e.g. the rocket won't turn or it wants to flip around. As long as you have a reasonable launch pad TWR, there shouldn't be a need to run at anything less than full throttle.

The game actually burned me once because of its inconsistent and confusing use of the word "fuel". I had accepted a contract to place in orbit a station that included 4 tons of "fuel". I figured this requirement would be fulfilled by including a "fuel tank" holding 4 tons of contents. But no, the contract wanted 4 tons of actual fuel, i.e. not oxidizer. This type of mixing of terms I find to be really frustrating. We shouldn't have a contract ask for "fuel" but then have the contents of a "fuel tank" not fulfill the contract. I really think the game should change all references to "fuel tank" to "propellant tank."

I generally like my liftoff TWR to be between 1.3 and 1.5. When I'm using an all liquid launcher, I prefer the low end of the range, about 1.3-1.4. When using solids, I prefer being closer to 1.5. Using a high TWR means that you can usually get to orbit using less Δv, but that's not always the best metric to go by. If you are playing a career game where funds matter, using a low TWR generally means that your cost per ton of payload is lower. This is because you can launch the same payload with a smaller and less expensive engine. Granted, you'll be less efficient in terms of Δv, but who cares if you are saving funds. As other have said, having a high TWR in orbit is not very important. Of course if you are using the same upper stage that you used during launch, then you're going to have a relatively high TWR. But if you are using a stage that is dedicated for use in space, then you generally want to use as small an engine as practical to save mass. The factor that I take into consideration when selecting the TWR for an upper stage is the length of the burn. If your burn is too long, inefficiencies are introduced because you are sweeping through a large portion of your orbit while burning. The rule of thumb is that you don't want to pass through more than about 60 degrees of an orbit while burning. For Kerbin orbit, this works out to about 5 minutes. Therefore, I like to have a TWR large enough that I don't need more than a 5-minute burn. In general, if you plan to perform an ejection burn of 2000 m/s, then you need a TWR at ignition of about 0.5 to limit the burn to 5 minutes. For smaller burns you can get by with a lower TWR, and for larger burns you may want a higher TWR.

The Kerbal adds mass only when in a command seat. His/her mass is not added when in a pod. That is, the pod's mass is the same whether crewed or not.

Just to confuse the issue, there is something called "propellant mass fraction". It is the fraction of the total mass that is propellant. The term "fuel" is often use (as a layman's term) when it would be more proper to use the term "propellant". For example, KSP calls it tanks "fuel tanks" when they should really be called "propellant tanks". Fuel is only part of the contents, with oxidizer being the other. The fuel and oxidizer are reactants that are mixed together and burned. The resulting combustion products form a reaction mass that is expelled from the engine to propel the rocket. Since both the original fuel mass and the original oxidizer mass are expelled as reaction mass, both fuel and oxidizer are propellants. In this example, the total mass is 9 tons, of which 8 tons is propellant. Therefore, the propellant mass fraction is, 8/9 = 0.889. Propellant mass fraction is just another way of looking at mass ratio, but it is mass ratio that is important in solving the rocket equation.

Actually that's not true. What determines a planet's ability to retain an atmosphere is its temperature and its escape velocity. Although Kerbin is immensely dense, it is still a relatively low mass body with an escape velocity of only 3431 m/s. A planet of its size, mass, and temperature shouldn't be able to retain any appreciable atmosphere.

@legoclone09,