Newbie Tips?

[Clockwork]

Hello, I was wondering if there were any tips that you guys had for me. I have some experience in KSP, I've been to both the mun and Minmus, I've escaped Kerbin's SoI, and I've gotten into (nearly) circular orbits of these three bodies. I can't dock, I've tried, so if you have any tips on that, that would be great. I haven't gone interplanetary yet, but I'm working on it. I know how to install mods and stuff, but the info that I get from MechJeb and KER isn't helpful yet (I don't understand it). If you could just help me out with some basic math and what the info mod stuff means, I would be very grateful, thanks!

Edited March 29, 2016 by Clockwork

[FullMetalMachinist]

I would start here:

Just look through it and read up on any topic that you'd like to know more about. There are also several good threads in the Tutorials sub forum. 

After that if you have any specific questions, ask those here. 

Happy to have you aboard, I hope you enjoy KSP! 

[maceemiller]

Welcome to the forums. I could spam you with link after link of info however I feel everyone should, like I did, benefit from these few simple words - Search Youtube for Scott Manley......

[N_Danger]

Welcome!

I'm new here too and this part of the forums is full of good advice that has helped me a lot. Just search it or ask a specific question and you'll get lots of great help.

Edited March 29, 2016 by N_Danger
Spelling.

[Clockwork]

1 hour ago, maceemiller said:

Welcome to the forums. I could spam you with link after link of info however I feel everyone should, like I did, benefit from these few simple words - Search Youtube for Scott Manley......

The Scott Manley Videos are actually what got me into KSP, I have no idea how I found him, but I'm here now!

[Plusck]

Don't worry about asking specific questions, even if they've been asked before. As long as it isn't something you'd find with a second's googling, nobody will mind.

As it happens, there have been a couple of threads about docking the last couple of days. This is the latest one (with a link in it to the previous thread):

If you don't understand the maths, delta-v, expressions used to define orbits and suchlike, but you are prepared to read and try to understand, then this page on rocket propulsion is quite simply excellent, as is this other page on the same site (www.braeunig.us/space/) on orbital mechanics.

As for the info in KER or MechJeb, the three most important numbers are:

a) Isp = specific impulse: basically how much working energy the engine can get out of each unit of propellant. Measured in seconds because it conveniently avoids any confusion with units.*

b) TWR = thrust to weight ratio: thrust being in newtons of force and weight (also newtons) being the mass in kilos multiplied by gravity (which is 9.81 on Kerbin). Must be more than one to lift off any planet or moon. Can be as low as you like in orbit if you have time to kill. Note that there is still plenty of gravity in orbit and therefore by definition you are not weightless, you just don't feel it since you're constantly falling. Also note that people seem to find "freefall" too un-sciency, so they make up terms like "micro-gravity environment" to avoid saying the (wrong and un-sciency) "weightless" even though there is nothing "micro" about the Earth's gravity at only 400 km altitude...

c) dv = delta-v: how much change in velocity your spacecraft can make. Absolutely and resolutely fixed by your mass, quantity of fuel and engine Isp (aka the rocket equation or one of the cold equations). Starting from KSC (velocity due to Kerbin's spin: 175m/s) you need to accelerate to about 2300 m/s to orbit at 70km. However, it'll require a dv of about 3200-3500 m/s to get there due to gravity losses, atmospheric drag losses, and steering losses.

So with those three figures, you know (a) how efficiently and (b) how powerfully you can go (c) from one orbit to another. KER just gives you the figures and helpful tools to use them. MechJeb also allows you to cheat qualitatively improve player experience by automating certain maneuvres.

* I_sp is essentially energy per mass, or thrust divided by mass flow rate. Thrust is exhaust velocity times mass flow rate, so by this first definition mass flow rate cancels out leaving: Isp = exhaust velocity. Velocity is distance divided by time, so I_sp could be measured as distance/time. However, in a geocentric model mass flow rate can be replaced by weight flow rate. Since weight = mass times g (which is distance per second per second), then you can bridge from one measure to the other by multiplying or dividing by g. Therefore by this second definition, I_sp = (distance / time) / (distance/(time*time), and the units cancel out giving I_sp = time. This should make engineers happy because they can discuss engine efficiency without worrying what units their fellow engineers are using for everything else, but it seems someone forgot to pass on the message so you'll still see a bunch of different units used to describe rockets, and even more for jet engines.

Edited March 30, 2016 by Plusck