Gaarst

Would it be possible to disable the 85% soft failure thing only on some parts? Playing RSS and Real Heat and I have issues with my heatshield exploding during reentry as it goes slightly over 85% max temperature. It triggers the max temp fall and causes explosion even though I'm pretty sure it wouldn't reach 100% of its nominal tolerance.

So I can't seem to be able to reenter a simple Mk2 pod from a lunar mission. Just the pod, a fully loaded heatshield and chutes. It used to be fine before 1.1 when I did not use DRE, but now I do and stuff explodes (I don't want to remove DRE). If I set my periapsis over 60km, I don't explode but I don't aerocapture, go back in space, run out of EC and everyone dies. If I set my periapsis under 60km the heatshield overheats and explodes (with over half the ablator left) and everyone dies. Tips? (I'll try and change DRE settings when I have access to my game this evening)

MLG KLAW V4.2.0!!! Out now, summons the Kraken so fast it violates locality! Summoning another Kraken in the process!!!!!1!! 99.9% chance of breaking your KSP saves but also other saves from other games from any computer in a 2km radius!!! Seen on TV!!!!!!! Yeah, no.

Go to GameData\KerbalEngineer\Settings and find the SectionLibrary.xml file. Then just copy-paste it to whichever install you want.

I think the Poodle is already powerful enough for its use as a vacuum engine. You don't need tons of TWR once in space.

1.1pre was on Steam only. And I got very upset over it The game went on Steam after 2012. Don't know when exactly. 3M is what I'd settle for. Half Steam half other. Edit: the game went on Steam somewhere between late 2012 and early 2013, according to a quick search on the forums.

If Squad breaks crafts everything is going to be on fire again (with riots and stuff on the forums). 1.0 had the excuse of being the official game release but a "mijor" (or "manor") update will trigger the apocalypse on the forums for sure.

lol

Works like a charm! Thank you!

@NathanKell Thank you very much for adding this in build 1509! Thing is even though I found the values to tweak in the Physics.cfg, I can't find the option to enable it in game. Am I blind, or did someone forget something?

Single Mk1 pod, no heatshield, peri at 10km and got no problem.

So I took some data during a LKO reentry with a pod, and here is what I found: while the convective heat coefficient reaches a peak around 30km and agrees pretty much with the presence or not of reentry effects (between 51km and 21km) appearing when it crosses a given threshold, the plasma frequency reaches a max around 28km and flattens out from 20 to 15km, allowing a maximum blackout period from 35 to 20km. NathanKell's criteria would mean a blackout period from 56 to 21km. Edit: note that the deceleration starts around 35km and ends below 15km

Doing some number crushing, results coming soon-ish.

Isn't 45-60km the altitude when reentry is the hottest? 45km is pretty low for plasma to kick in.

Wouldn't it be more accurate to calculate Ne as shown in the page Jovus linked with the Saha equation? And cut communications when the plasma frequency goes above a given threshold (dependent on Ne)? I believe than even though pretty simplified it could be accurate enough for KSP's model. And since all the 3 threshold constants you suggested are the variables of the equation, it would essentially be the same, only with the resultant number only mattering in the end. As the plasma frequency would be calculated, the only setting to be tweaked on the used end would be the frequency of the communications. Though that would mean setting it to an absurdly low value to have actual blackout during Kerbin entry. Edit: then an upgrade to the communication system to avoid this could just be a simulating frequency increase. Also, for blackout during ascent, I don't really see how this could be fixed as on Kerbin most of the orbital velocity is gained during the actual ascent phase, when inside the atmosphere. For Earth the speeds at which blackout may occur are reached above the atmosphere so it can't happen, but for Kerbin, I often reach orbital velocities while still below 60km (with a flat profile and reasonable TWR).

Thank you for this! Do you have default values for ABC or will they have to be set manually? (I don't mind taking some time to tweak them to achieve a good result) Edit: also will the whole craft be occluded? As The_Rocketeer quoted, the space shuttle had a small opening in the plasma layer at the back. Since I guess this would require a more advanced model I suppose all the comms will be cut for the next pre.

Since you have functions of both time and position, you need to find a way to relate the two. The easiest would be to calculate h(t) which is just an integration of your vertical velocity during the launch. So you do need to know your trajectory to some extent. To get the rotation speed is hard and annoying. You first need to work out the torque created by your engines gimbal. T = rxF (vector form) or T = r*F*sin(G); here T is the torque, r is the distance from your engine to the centre of rotation of the rocket and G is the gimballed thrust angle. To get the exact position of the centre of rotation, you would need to do stuff with your aerodynamic centre and CoM (which calculations I don't know). Note that this assumes a single engine inline with the centre of mass. Once you have the torque created by the engine, you need to calculate the torque created by the drag by integrating the drag at each point of your rocket over its entire length. This will depend on your speed, the air pressure around you, the angle of your rocket relative to airflow. This is for gimballed rotation. For gravity turn you would need to again integrate stuff; this time gravitational pull and drag over the length of your rocket (knowing where the CoM of your rocket is to obtain a torque), add this to the thrust of your rocket to obtain a resultant torque and thrust. Finally you would need to integrate this thrust and torque with respect to your trajectory (time or position) and you will get your gravity turn. That would be an ideal area. In real rocketry, the nozzle has a given expansion. If the engine is optimised for atmospheric use then the exhaust will be over-expanded in lower pressures; and if it is optimised for vacuum use then the exhaust will be under-expanded in higher pressures. In both cases you will lose efficiency. Now KSP's engines properties are completely independent of its architecture (note how the Poodle, a vacuum engine, has a ridiculously small nozzle), so the actual area you can measure in game and the one you'll get by calculations will be different. Thing is KSP's model is simplified, and as Isp curve with pressure is programmed into the part itself, using the "ideal" area you can calculate using the asl and vacuum Isps (or thrust) should give you accurate results. I expressed mf as a function of throttle after I wrote down the equation for F, so I kinda forgot to include it. F is a function of h, t and mf (or throttle). Of course, you can reverse mf and F the equation and express mf as a function of h, t and F. Just remember that F is dependent on external conditions (h and t) while mf is only dependent on throttle that you directly control. That's the Oberth effect. This doesn't change the dV of your stage but how efficiently this dV can be used. So in the end it does influence your trajectory. The Oberth effect depends on your velocity relative to the gravitational speed you are in.

So, TWR is given by: TWR = F / (Mg) with F the thrust, M the mass of the rocket and g the gravitational acceleration. M is a function of time with M(t) = M0 - mf *t; here mf = dm/dt is the mass flow rate and M0 is the wet mass of the rocket. F is both a function of time and position. F(h,t) = Isp(vac) * g0 * mf -- A*p(h). Isp(vac) is the vacuum Isp of your engine (in s), A the area of the nozzle and p(h) the ambient pressure. g is a function of position: g = g0 / (h / R)2 as you wrote it. A can be found using the equation for thrust: A = Isp(vac) * g0 * mf * (1 - Fasl/Fvac) / p0. Fasl and Fvac are the thrusts of your engine at sea level and in vacuum, and p0 is the pressure at sea level. p is annoying because it is a function of temperature and height. Since we have neither temperature nor pressure numerical data, you need to either: bring a barometer on your rocket and measure, assume constant temperature, or solve stupid integrals. is the formula you need for this (replace z with h). If everything is constant (temp, molar mass of the atmosphere and g) this simplifies to p = p0 * exp(-Mgh / RT). Note that here M is the molar mass of the atmosphere and not the mass of the rocket. This is the easy part. To precalculate the throttle needed to keep a constant TWR in a specific profile, you'd have to know your trajectory exactly and express the TWR function as a function of time only: you need to express position (height is enough) as a function of time, hence you need to know your trajectory, then you'll get h(t). Now replace h by h(t) in the equations above and you'll get your TWR. Once you have your TWR, know that the throttle changes the mass flow rate dm/dt (Throttle is proportional to d2m/dt2), so that: mf = dm/dt = Throttle * mfmax (throttle is between 0 and 1), and change your throttle function so that your TWR stays constant. It's not mathematically complicated, just tedious. Make a spreadsheet calculating the different values (one at a time) and combine them to get TWR. If you want acceleration, then you'll have to consider not only height but 2d movement, heading of the craft, of the thrust and of the trajectory, and drag. Good luck on that.

Probably a three digit number.

Darn you, I just spotted this and was about to write it here... Screenshot below (don't look if you don't want to see where it is):

Now that we have communications (or soon) to add a little realism to magically controlled probes, it could be a good thing to add communications blackout during the "hot" phase of reentry. As a spacecraft reenters atmosphere, the shock heating creates a layer of plasma around the craft. As plasma is essentially a fully ionised gas, it is charged, and generates an EM field which messes up all radio communications towards or from the craft. It might add a little difficulty and challenge to atmospheric entries of unmanned crafts (for manned craft you just wouldn't be able to transmit science during this phase).

Used and abused autostruting and finally made my Soyuz fly successfully! It flies nicely if you forget that it wants to roll clockwise for some obscure reason. http://imgur.com/a/Xh0uf

This ^ Also, who even cares if engines having machinery is realistic or not? If you want realism you will clip the engines inside another part to only let the nozzle out because no rocket has all the pipes n stuff hanging out. In both cases you don't see the machinery from the outside.

Me be back. My previous design couldn't orbit due to abyssimal TWR, but I used 1.2 and the T30 buff to get it to finally fly! (Only to realise it is way too wobbly to go anywhere but straight up) Album here: http://imgur.com/a/tQGlw Engine layout (non gimballed engines + verniers) and sizes of all stages are accurate. Mass is still far from being the same as the real one (500t). Still need to fix the wobbling to make it fly properly, and I will probably change a few more things (especially on Block A).

Vega is one of my favorite rockets: (almost) all solid, and it's so cute!