Starman4308

Career mode was reasonable for new players back in 0.25: while contracts could be a bit confusing, and the absence of any starting probe core was silly, at least new players had all the tools they needed to understand what they were doing. With 0.90, Squad decided new players didn't need confusing numbers like "basic orbital information" or "sphere-of-influence transitions". If all this stuff had come as a hard mode, it'd be understandable, but they decided to take a baseball bat to career mode, and hardcode it so that it's impossible to mod.

Two things to consider. #1: The planet is spinning under you as you fly. You're going to have to aim eastwards of your target, or you're going to miss the target. #2: The Trajectories mod, when it gets updated to 0.90, can give you quite accurate landing predictions, accounting for things like planetary rotation.

I've got to go soon, but two things. First, were you trying the rocket in FAR or stock aero? Second, FAR doesn't have to destroy your rocket to cause problems: if it causes your rocket to flip over, you're just as doomed.

Semi-by-intention. StupidChris is going to try to give an option for right-click resizing in the near future, but is otherwise not going to let you change parachute behavior until you get access to action groups.

In terms of pure delta-V available, you still should burn the SRBs first. Otherwise, you burn efficient liquid fuel hauling around inefficient solid fuel. In the presence of atmo and gravity drag, it returns to a question of "it depends", because the solution involves the standard batch of partial differential equations. I think I might've been in a rush to catch a bus or something. I apologize for the vague wording. I don't, at least not from a practical standpoint of "actual FAR launches". The #1 point is based on gameplay experience of trying to wrestle 1.6 TWR rockets down onto a proper gravity turn instead of shooting off vertically to space. A 2.0 TWR is simply too much for an efficient launch in FAR: you lose too much going straight up against gravity, and not enough going horizontal, and that outweighs any savings you might gain from the quicker acceleration. The reason a lot of people say it is because it's true: high TWR rockets are nightmares to handle in FAR, and real rockets shy away from high launch TWR* because they would tear themselves apart from aerodynamic stress: they have to be designed for max-Q. That doesn't really happen in FAR, probably because Ferram gets too many complaints from inept designers already, so you need to really try to get aerodynamic failure in FAR. *Other than a few which use SRBs for the first 30 seconds or so. Then they go back down to reasonable TWR. EDIT: Unless what you meant was "ignore, ignore, ignore the practical issues", in which case it returns to the #1 point: does the dV increase from not lighting up the LFE until after SRB burnout counteract reduced gravity/atmo drag? I don't know, because I don't have any quick simulators handy.

Only one of those is true. The Kerbal X has got its problems, such as wimpy asparagus staging and poor solar panel layout. Granted, I like the idea of the stock craft: almost-good craft with problems for new players to fix.

That sounds excessively complex, particularly at the "very high pressure" part. Also, I'm not sure you can get NTR reactors to go from partial to full output on a dime like that. How about you just run some of the reactor coolant through lines running through the fuel tank? It wouldn't require much piping, and it might be a good idea to keep the propellant liquid anyways, so as to avoid any freeze/thaw issues from cropping up.

Ammonia and methane are both reasonable choices. Methane would probably require a bit of active cooling, and has issues with leaving carbon residue. Ammonia has one amusing problem: there's a good chance you might need to melt it before use.

I suspect what is going on in FAR is that, once you start getting some AoA, you start to get body lift: the entire rocket starts acting as a wing, causing your CoP to go far forwards. Once CoP is in front of CoM, all sorts of fun things start happening. In stock, since all drag is proportional to mass, etc, drag remains centered on CoM, so you never get these problems. EDIT: Also, 95% sure what I was thinking on part #2 of my initial post was that, if you don't start your LFE until after staging the SRBs, you get more dV, because you aren't spending any of your liquid fuel hauling the SRBs or their fuel. There's a good chance that will outweigh any savings from reducing gravity drag by going full-thrust from the start. I also tested the body lift thing: when you use FAR to tint lift, you start getting a lot of tint on your fuel tanks if you tilt your rocket at high velocity.

Yes, because if you try launching with an overly-high-thrust rocket in FAR, you'll have a lot of difficulty making your gravity turn. Even 1.6 is difficult to manage: 2.0 would be a nightmare. You'd go shooting off to a ridiculous apoapsis without having gotten much horizontal velocity. EDIT: In short, FAR's changes to aerodynamics aren't just drag: it also brings in various other questions of aerodynamics, and those limit TWR as well.

The practical answer is "2.0 is already way too much TWR to have for more than ~30 seconds: throttle down those SRBs some". The semi-practical answer is "You lose so little to aero drag in FAR that you probably want to leave the LFEs alone". The theoretical answer is "Run simulations to get your answer, because it is one of those questions with the most evil answer ever: 'it depends​'".

With a few major caveats, you don't need a big rocket to get to space. The rocket equation specifies a payload fraction, but not a minimum rocket size: in theory, you could build a 50 gram Ariane 5 and get a 1g payload to orbit. The primary difficulties are atmosphere (inertia/thrust scale as the cube, atmospheric drag scales as the square), difficulties engineering small, efficient liquid-fuel engines, and difficulties engineering small control systems and radios. These factors impose certain size limits on rocket boosters, but it's not as steep as one would think. Suborbital rockets can be just a few hundred kilograms, and the smallest orbital rockets I've seen were in the range of 9-10 tonnes (the Vanguard and some Japanese rocket).

Did it on the start node: parachute, command pod, antenna, 10x FL-T200 fuel tanks, LV-T30 engine, and an RT-10 beneath all that. It did take advantage of explosive decoupling: when the RT-10 was almost out of fuel, I kicked on the LV-T30, causing the RT-10 to overheat and explode. It should be possible to do it with normal decoupling as well if you've unlocked basic rocketry. Didn't quite have the juice to make a Mun flyby, sadly. I used to be able to do that, before Squad implemented launch pad limits, but the best I could do with just one RT-10 was about a 2,000 x 75 km orbit.

No, for several reasons. The simplest one is that that assumes you are traveling in one direction (such as straight up), instead of a ballistic trajectory. Another giant complication is atmospheric drag, which is going to destroy one of the primary assumptions of that equation, particularly when using stock atmo. In order to actually solve it, you'd need to integrate a number of particularly nasty partial differential equations... which would pretty much mean "try it in KSP until it works with the least fuel*". *Technically speaking, KSP is, indeed, a program which solves these partial differential equations numerically.

Much like going to orbit, it's rather spectacularly dependent on your ascent profile. I would probably aim for something which can get to orbit: there's a good chance you'd need some of that fuel for last-minute corrections anyways.

Nope. That's the mass with fuel. The dry mass of the FL-T400 is 0.25t. That's true of all fuel tanks: the listed mass is when filled with fuel. You're also, as mentioned, losing giant quantities of velocity on launch. When launching straight up from KSC, you lose 9.8 m/s each second to gravity. You are also losing velocity to atmosphere, at a rate proportional to atmospheric density and the square of velocity. As it works out, the most efficient way to do things is to ascend at terminal velocity: when gravity exactly matches atmosphere. This means that, for the first part of the ascent, the most efficient TWR is slightly greater than 2.0*: 1.0 to counter gravity, 1.0 to counter atmospheric drag, and a little bit left over to accelerate as terminal velocity increases (due to thinner atmosphere). As such, you generally design for 1.6-2.0 launch TWR: the advantage of going a bit less than 2.0 TWR is that you will burn fuel on the way up, and if you need to throttle down to stay at terminal velocity, it means you're carrying wasted engine mass. *If you use traditional staging, the most efficient launch TWR seems to be about 1.65: you'll burn fuel and increase your TWR on your way up. It'll be different for different staging schemes: something like asparagus, onion, or twisted candle can remain very close to optimal TWR by frequently staging off excess engines. Please note that much of this advice gets thrown out the window if you install FAR or NEAR, which change aerodynamics significantly.

Did you wind up changing any fuel capacities? The RealFuels config requires good volume numbers, but winds up discarding whatever the original mass of the tank was.

It's still a WIP, but there's a second 2-man capsule in more of an Apollo/Orion type shape.

All of it. There's no real distinction between "crash report" and "bug report". A crash is either a bug, running out of memory, or a fluke. In case 1, we can probably help you, in case 2, we can show you how to reduce your memory usage, and case 3 is basically up to the whim of the computer gods.

These are the general guidelines you should follow. Be aware that if it is just one isolated incident, there's a chance it's just a completely random hiccup. If you can replicate it, it's more likely to be genuine, and easier to track down.

Not everything here is helpful: a lot of it is sarcasm. The short version is that the equation involving a logarithm is the simple way to do it. For pure plug-and-chug, this is how you do it. #1: Divide your starting mass (with fuel) by the ending mass (without fuel). #2: Take the natural logarithm (ln) of the resulting number. For many calculators, you can just press an ln button after you calculate the above: otherwise, you might have to get it like the following and press enter. ln(answer) #3: Multiply by g (9.82) and Isp (dependent on engine type). There, you're done. If you wish to know what the natural logarithm is, a reasonable source of information is the 22'nd chapter of Feynman's lectures on physics. The very short version is that exponentiation is repeated multiplication: a^b is a multiplied by itself b times. As such, 3^4 = 3*3*3*3. The logarithm is the inverse operation: log base a of b = c, where a^c = b. To restate, the result of the logarithm is the number to which you must raise a, so as to get b. The natural logarithm, ln, is simply log base e, where e is a fairly special number in mathematics. It's coded into most calculators: for now, all you need to know is that you use the natural logarithm.

Expect RO to take its sweet time about updating, on account of its large number of dependencies. You'll know it when you see 0.90 in the thread title, or possibly when you see it in this thread.

Slashy, I pointed this out. Cd for terminal velocity is dependent on what Cd would be at terminal velocity. Your current Cd is meaningless. It is what Cd is at terminal velocity: yes, that is a bit recursive, but that's how terminal velocity works.

Because you clearly don't. Terminal velocity is independent of what is going on with your craft. It is dependent solely on atmospheric pressure and craft aerodynamics. Your current drag is meaningless: the only important thing is drag at terminal velocity and gravity. You can be going at 0.1c and accelerating at 600 gravities, and instantaneous terminal velocity would be the same as if you were in free-fall. From Wikipedia: Vt = SQRT((2mg)/(pACd)). There is mass, there is gravitational acceleration, there is atmospheric pressure, there is cross-sectional area, and there is the coefficient of drag. None of these variables are in any way dependent on the current velocity or acceleration: they depend solely on aerodynamics, atmosphere, and gravity. Vt comes out of equating Fd with Fg: essentially, "at what velocity will drag equal gravity". Velocity is in there only once (in drag), and can be solved for, getting you the above equation. EDIT: And to remove any possible remaining confusion: the Mach multiplier (which is an approximation itself) to apply to Cd would be the Mach multiplier you would see at terminal velocity. The only reason FAR prints it out based on current velocity is because it'd be too much of a pain to figure out exactly what terminal velocity is. EDIT #2: And if you're wondering "then why does Vt change as my rocket flies!", it is primarily because you are changing altitude (and thus local atmospheric density and gravity), and secondarily because of aforementioned wonkiness in how FAR estimates Vt.

What FAR gives you is, indeed, an approximation, because it's calculated with the current Mach multiplier so as to save time*. Regardless, Slashy is still continuing to misunderstand what terminal velocity is: it is, was, and forever will be the speed at which drag force equals gravitational force (independent of vector), and happens to be the speed at which your object would fall. There is no dependence on thrust: terminal velocity is a function solely of aerodynamics (atmospheric density, object shape, object orientation relative to direction of travel) and gravity (technically also buoyancy in the real world). It is also an instantaneous number: technically speaking, your object will probably be falling a bit faster than terminal velocity, because it's falling down from thinner atmosphere. In order to converge on instantaneous terminal velocity, you would need to extend out that band of atmosphere and gravity infinitely far. However, generally speaking, by the time you hit lower atmosphere, a falling object is usually pretty close to its terminal velocity. *Because you generally only need to know if you should speed up or slow down, it's really not worth trying to iteratively pin down exactly what Mach multiplier to use. If you're near terminal velocity, it should be quite accurate anyways.