Math

[Lar-E]

I've been playing the game for a month or so now, and so far my engineering technique has been pretty much that of a Kerbal rocket scientist: massive overkill and trial-and-error. I'd like to start incorporating some math into my game play... i.e. 'Will this craft actually reach orbit?'; or more pertinently: Jeb has about 1/3 of a tank left in the lander... can he land on the surface of the Mun, pick up poor stranded Bob, and still achieve Mun orbit with his remaining fuel?

What is a good starting place for actually doing this all scientific-like?

[UbioZur]

I would says you need two things if you stay stock:

- a delta-v map (and understanding of what delta v is), there are plenty available on the forum (i.e. http://forum.kerbalspaceprogram.com/showthread.php/25360-Delta-V-map)

- the equations: http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Advanced_Rocket_Design

it's fun for the first few time, and great to understand a bit more how things works, then it start being a bit long to calcul and test everything (to my opinion). So mod like Kerbal Engineer can process and display the info for you.

And for additional knowledge, here are a few charts that the community have made:

http://imgur.com/a/okuO4

http://i.imgur.com/dXT6r7s.png

http://imgur.com/a/kfnng

http://forum.kerbalspaceprogram.com/showthread.php/37327-Atmospheric-Landing-Charts-Pinpoint-landings%21-NEW-UPDATE-No-Protractor-Required%21

Edited September 17, 2013 by UbioZur
kerbal engineer link

[papics]

Reading these will help very quickly:

http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Advanced_Rocket_Design

http://wiki.kerbalspaceprogram.com/wiki/Cheat_Sheet

http://forum.kerbalspaceprogram.com/showthread.php/28352

Have fun

[Monkeh]

Install the Kerbal engineer redux and let it do it for you. It's only a calculator and you can take those into exams, so it's all gravy.

It's easy to install and when you clip a massless part onto your ship it will tell you delta v's, thrust to weight ratios, mass etc, for the whole craft and for each stage individually. You can also set it to give you readings for different planets and moons as well.

Want to know how much delta v that nuke tug you've built gives you in the vacuum of deep space? Easy, click a couple of buttons and it's all there for you.

[astropapi1]

Yeah, Engineer will give you lots of useful numbers. It's a must-have for rocket designers. Even stock ones.

[lajoswinkler]

First be sure you know the basic Newtonian physics. Maybe it looks like "everyone playing KSP knows it already" but that isn't the case.

[Monkeh]

Forgot to mention that the engineer thingy updates in real time too, so you can see EXACTLY what happens to your craft if you replace that mainsail with a 4 stack of nukes, (Spoiler: Tonnes less thrust to weight, MEGAtonnes more delta v.), instantly. It will really help get the most efficient design sorted.

So far I have worked out the lower your thrust to weight, (from orbit at least), the further you will go in the end. The way to be super economical is to have a single nuke pushing a hundred jumbo tanks. It might take you 5 years to increase speed by 10 m/s, but you'll be burning forever!

[capi3101]

Whether or not you should use KER is up to you, of course. If you've got a mind to do the math yourself, I say go for it. If not, KER's your answer. Me, I used KER as a reward to myself for successfully completing my first round-trip interplanetary mission (putting Jeb on Gilly and getting him back to Kerbin safely, specifically), so I use it (one of three mods I use) and I can tell you it is an incredibly powerful tool. Like most mods, it's not foolproof, though.

Even with KER, the delta-V map is essential for planning mission stages. That way you can say to yourself "okay...I know it takes this much to get to Jool, this much to orbit Jool, this much to get to Tylo from Jool" and so forth. You then make sure your craft is capable of generating the amount of delta-V you need for each stage of the trip. Work it backwards.

If you want to do it the hard way, learn how the Tsiokolvsky Rocket Equation works, and get to the point where you can work it forward and backwards. Having a good scientific calculator is a must; alternatively, use Excel (=LN() is the Excel function for the natural logarithm, =EXP() is the Excel function for e).

[Specialist290]

As I always do whenever this subject comes up, I'm going to recommend reading these four helpful pages over at Atomic Rockets. They're meant to serve as a way to ease laymen into the basic calculations needed for rocketry and spaceflight.

The rest of the site is worth a read, too, although not all of it can be easily applied directly to KSP.

[WafflesToo]

KER really is a nice tool, but I recommend doing it yourself a few times to get a feel for it. That way when KER spits out a bad result you should be able to spot it.