What's The Best Way To Learn Theory?

[stephensmat]

I've been playing casually for a while now. I'm still trying to master the art of landing without a chute, but building and navigating I can do.

What I'm having no luck with? Actually building a space program. The game is not set up in individual levels. You launch a mission, it finishes, you start another one. Except this game is designed to have multiple missions going at once, building on each other.

The tutorials take you through the controls and the methods of how to do things.

But I'm only grasping half of why things work. It's like cooking. I can follow the recipe, but I can't improvise. I need the theory.

Where's the best place to learn these things?

[RizzoTheRat]

This is a good place to start http://www.braeunig.us/space/orbmech.htm (run by OhioBob on here).

I've learned way more about orbital mechanics since I started using Kerbal Operating System, as I now programme all my manoeuvres and don't use manoeuvre nodes.

Edited January 5, 2020 by RizzoTheRat

[Snark]

9 hours ago, stephensmat said:

But I'm only grasping half of why things work. It's like cooking. I can follow the recipe, but I can't improvise. I need the theory.

Got any specific examples? i.e. some specific "how do I figure out <thing> in <situation>" type of question that you're interested in or is especially vexing you?

[stephensmat]

8 hours ago, Snark said:

Got any specific examples? i.e. some specific "how do I figure out <thing> in <situation>" type of question that you're interested in or is especially vexing you?

The math/result of ship design mainly. On launch, my craft get tossed around; the fuel runs out mid-mission; that sort of thing. I know it's got something to do with symmetry, weight ratios, etc.

I don't mind having to make four attempts to get it right. I just prefer to know what I'm doing wrong.

[Snark]

Just now, stephensmat said:

The math/result of ship design mainly. On launch, my craft get tossed around; the fuel runs out mid-mission; that sort of thing. I know it's got something to do with symmetry, weight ratios, etc.

I don't mind having to make four attempts to get it right. I just prefer to know what I'm doing wrong.

Those are not uncommon problems. 

The devil's always in the details, though.  For example, "craft get tossed around" is a very different problem from "fuel runs out mid-mission".  There's not going to be one "general help", really-- KSP is a bunch of very specific, very focused individual problems, and each one of those has different potential causes and different solutions, and is best addressed separately.

In general, the best way to get help for this sort of thing is to post a question to Gameplay Questions-- and for best results, make it as focused as possible.

For example, let's say you wanted to address the "craft get tossed around" thing-- I have no idea exactly what you mean by that, "get tossed around" is pretty vague.  So, for example, you could post a topic to Gameplay Questions, asking "Why do my craft get tossed around on launch?" for the title.  Then describe, as specifically as possible, what happens, something along these general lines:

Quote

It seems like lots of my ships have a problem, in which when I launch, <specific bad thing happens>.  Here's a picture of one my craft where this happens:  <screenshot>  Can someone explain what's going on, and how I can avoid this?

...Or something like that.  Don't worry if you don't get the wording perfect, or aren't sure how to describe it-- that's a common problem.    If what you've said isn't specific enough, people will post clarifying questions so they can zero in on the issue.

In general, always include a screenshot of the problem, if you can-- a picture's worth a thousand words, and lots of KSP problems can be identified at a glance by someone who's experienced.

Anyway, that's my suggestion.  Post a Gameplay Question thread for your get-tossed-around problem, and another one for your run-out-of-fuel problem.  For the former, be sure to describe just what you mean by "tossed around" and under what circumstances it happens, if possible.  For the latter, a description of the intended mission is helpful.  In both cases, include a screenshot.

Good luck! 

[KerikBalm]

https://wiki.kerbalspaceprogram.com/wiki/Cheat_sheet

For the running out of fuel problem,

Make sure to use the oberth effect: https://en.wikipedia.org/wiki/Oberth_effect 

Make your transfer burns from as low of an orbit as possible, raise periapsis from apopapsis. For plane changes, do them at the ascending/descendingnode that is as high as possible. For very large plane changes, you should do a burn so that an An/Dn is also the apoapsis (so you are moving as slow as possible at An/Dn so that the plane change is cheaper).

Ksp now has a dV calculator, but the theory behind it is this: 

https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

To know how much dV you need, a "map" is useful

For bodies larger than Mun (such as duna), you can save fuel by sending down a lander that can only get back to orbit, but lacks the fuel to return to kerbin. Leave a fuel depot in orbit, and dock with it. Think about the fuel needed to go from duna orbit back to kerbin. Why would you bring that down to the surface of duna, and then back to duna orbit again (requiring you to bring more fuel to duna to do that, requiring a larger rocket on kerbin to send that extra fuel to duna), when you can leave it in orbit and go down to the surface and back up again?

 

[RizzoTheRat]

10 hours ago, stephensmat said:

The math/result of ship design mainly. On launch, my craft get tossed around; the fuel runs out mid-mission; that sort of thing. I know it's got something to do with symmetry, weight ratios, etc.

I don't mind having to make four attempts to get it right. I just prefer to know what I'm doing wrong.

For fuel usage there's some helpful dV maps around to give you an idea of how much dV you need to get to various places, or you can do the maths yourself if you break the flight down in to the relevant sections, although launch/landing calculations are beyond my ability as it depends so much on your flight profile.

I assume by craft "tossed around" you mean it flips at some point?  that happens when the aerodynamic centre gets ahead of the centre of mass, so either add fins to the back or move the centre of mass forward.

For launches in atmosphere the launch profile and the ship design are closely linked, you have 2 types of loss to think about gravity (any time spent burning upwards) and aerodynamic (increases with speed, decreases with altitude).  The maths to calculate an optimum ascent profile is hideously complicated so nobody does it (although there is a mod somewhere that recreates the Space Shuttle guidance algorithms), but it worth experimenting with a bit, and you'll pretty soon start to get an idea of that works.