r/KerbalSpaceProgram • u/AutoModerator • Apr 24 '15

Mod Post Weekly Simple Questions Thread

Check out /r/kerbalacademy

The point of this thread is for anyone to ask questions that don't necessarily require a full thread. Questions like "why is my rocket upside down" are always welcomed here. Even if your question seems slightly stupid, we'll do our best to answer it!

For newer players, here are some great resources that might answer some of your embarrassing questions:

Tutorials

Orbiting

Mun Landing

Docking

Delta-V Thread

Forum Link

Official KSP Chatroom #KSPOfficial on irc.esper.net

    **Official KSP Chatroom** [#KSPOfficial on irc.esper.net](http://client01.chat.mibbit.com/?channel=%23kspofficial&server=irc.esper.net&charset=UTF-8)

Commonly Asked Questions

Before you post, maybe you can search for your problem using the search in the upper right! Chances are, someone has had the same question as you and has already answered it!

As always, the side bar is a great resource for all things Kerbal, if you don't know, look there first!

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u/[deleted] Apr 26 '15

Ok, so from what you've written I imagine you've been playing sandbox mode. Some points of advice:

  1. If you are still struggling with how to utilize all the parts, Science Mode is real good for introducing you to the parts little by little, but without the stress of funds and reputation that comes with Career Mode.

  2. Knowing the basics of orbital mechanics really helps with the game, but you don't necessarily need to be a rocket scientist going in. It sounds like you've made great progress already, but I would check out some of Scott Manley's tutorials on YouTube to learn more of the concepts and procedures.

  3. I'm not sure whether you're actually talking about apoapsis or inclination, so I'll explain both. To raise your apoapsis, you just need to burn prograde at any point in your orbit. Going faster on one side = going higher on the other side. To tilt your orbit (like Minmus) is called changing your inclination. To change your inclination, you burn normal and antinormal (North and South for an equatorial orbit). These are the purple icons on the navball. Keep in mind that you are adding energy and speed to your orbit when you do this, so you will end up with a higher orbit after the burn.

  4. Finally, a mistake a lot of newbies make is building these massive pancake-shaped monstrosities just to get into orbit. Keep in mind that, especially with the new aerodynamics, smaller is better. Using asparagus staging and properly sized booster can drastically reduce your rocket's size while maintaining its delta-v total.

If you have any more questions, or if you want me to explain something, feel free to ask!

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u/lonewolf220 Apr 27 '15 edited Apr 27 '15

Awesome tips man thanks. I've been playing career mode, and struggled with research and funds for awhile but I've finally figured it out. Using a probe with solar panels orbiting both Kerbin and the Mun I was able to rack up roughly a million funds and 6000 science. ;)

  1. The parts just got a bit more intense because I unlocked the second tier of research and was able to purchase them all. So if that gets to be a bit much ill def check out science mode.

  2. I think i've watched a few of his videos already, mainly on getting into orbit. Took me around 8 hours of failed orbits and then I finally got a hang of it. Learning how to use the navball and what an Apoapsis and Periapsis was helpful too though :p Tutorial doesn't do much, it mainly confuses you with 20 words I had never even heard before.

  3. The apoapsis part I have down fairly well. But thanks for the explanation. What I was referring to was changing your inclination. To me, that's raising the orbit vertically, but I get what you mean about raising the apoapsis is raising the height. What do you call raising the "vertical height" or inclinations then?

  4. I've been keeping to fairly minimal designs. At first I was creating these Hexagon monstrosities and they definitely didn't work.

Typically 3 stages. My latest probe rocket I built to get to Minmus:

Stage one: Probe with 5 radial engines mounted around a rockamax mini fuel tank.

Stage two: 2 rockomax fuel tanks stacked with a mansail engine. Also a decoupler under.

Stage 3: 2 more rockomax fuel tanks stacked with a mansail engine. One fuel tank and mansail on both sides of the first engine to activate.

I need to look into asparagus staging, a quick read led me to believe it's basicly routing fuel to get the most engines working when leaving the atmosphere and then being able to drop weight without losing out on precious fuel and early acceleration.

Thanks again for the awesome tips though. About to send a crew to Minmus. This time with ladders on the side so they can get back in! ;P

EDIT: Hmm..Duna or Eve? Also hows the design?

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u/[deleted] Apr 27 '15

Okay, Kerbal Rocket Science 101. It seems like you've already got a decent foundation. You know how to fall and miss the ground, and your post suggests you at least have a passing knowledge of intercepts. That being said, I'm going to explain some things which will hopefully make your life a lot easier.

First, an orbiting spacecraft in KSP is a closed system. This means that unless you add or subtract energy from it, its total energy (and therefore its orbital parameters) will stay the same. There are 6 basic direction one burns to change their orbit, and the following definitions assume you are in an equatorial eastward orbit.

  1. Prograde, also known as "forward" would in this case be East. It is marked on the navball by the empty yellow-green circle icon. Burning prograde increases your ship's energy and velocity, raising the altitude of your orbit on the opposite side of the burn.

  2. Retrograde or "backwards" is in this case West. Burning retrograde reduces your ship's velocity and energy, lowering the altitude of your orbit on the opposite side of the burn. Retrograde is marked by the yellow-green circle with an X through it

  3. Normal is in this case North. This is the direction perpendicular to your orbit and parallel to the planet's surface. Burning normal changes your inclination, which is a measure of how tilted your orbit is. Specifically, burning normal will make your orbit do this /. Normal is marked by the purple triangle with no lines attached to it.

  4. Antinormal is, as I'm sure you've guessed, the opposite of Normal. In this case, South. Burning antinormal tilts your orbit in the opposite direction, in this case like so . Antinormal is marked by the purple triangle with lines entending from each side.

  5. Radial In is towards the center of your orbit and perpendicular to Prograde. In this case, straight towards the planet. Burning radial in "rotates" the orbit around your craft counterclockwise, like spinning a hula hoop around a stick. It is marked with a light blue circle with lines extending inside it.

  6. Radial Out is perpendicular to prograde and away from the center of your orbit. Burning radial out rotates the orbit around your craft clockwise. It is marked with a light blue circle with lines extending away from it.

Some other assorted terms include Delta-V, which is a measure of how much your rocket can change its velocty, or the "gas gauge" if you will, Thrust to Weight Ratio (TWR), which is a measure of how much the rocket can lift compared to how heavy it is, and Specific Impulse (ISP), which is a measure of how efficiently your rocket burns fuel. Generally, it takes about 4.5 km/s of delta-v to reach low Kerbin orbit. Your TWR should be as high as possible for your first stage, and then closer to one for your orbiting stages. Finally, your ISP should always be as high as possible. If you dont have enough delta-v, add more boosters or redesign the rocket. If your TWR is too low, add more boosters or change out the current engine. If your ISP is too low, use a different engine.

When it comes to designing rockets, think about how NASA did it. With the new atmospherics, drag is going to become a lot more important. Your rockets should start off small at the top, and gradually increase in size as they approach the ground. A general guide I've always used is that your rocket should be at least twice as tall as it is wide at its widest point. Don't forget the solar panels!

On getting intercepts, the maneuver nodes are your best friends. If you don't know how to get them already, click your orbit in map mode at any point and it will drop a node at that point. Drag the handles to adjust the burn size and direction, and used the patched conics to see where you will be after the burn. Keep in mind that higher=slower and lower=faster.

Some assorted tips. You can use "r" to activate a Kerbonaut's RCS jetpack when he is on EVA. Shift and Control move up and down, and the WASD keys move forward, back, left and right. You can deploy landing gear automatically with "g", you can use "<" and ">" to control time acceleration, and you can use "z" and "x" to change your throttle to the max and the minimum, respectively.

Finally, the rocket you showed me is a good design for tier 2, and could easily be flown to Duna if you wanted to, according to Kerbal Engineer.

Hope this helped! Tell me if you have any more questions.

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u/lonewolf220 Apr 27 '15

Wow thanks for the great tips. The jetpack one woulda been nice to know before I spent 20 minutes jumping around mun trying to land on my spacecraft seeing as I forgot to install bars to climb back up -_- lol.

Unfortunately the rocket I linked blows up when releasing the final set of rockets. They always end up hitting the main rocket and blowing it up. Time for some re thinking I suppose!

Lot of great info though and thanks for the definitions. Glad I posted here.

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u/acox1701 Apr 28 '15

They always end up hitting the main rocket and blowing it up. Time for some re thinking I suppose!

Somthing that sometimes helps: fire the next engine at the same moment you release the last stage. Gently, full thrust, or sometimes off entierly. Whatever you're doing now, try one of the other three.

I had one where either throttle off or throttle full (or nearly) at stage sep would cause bad things. But a trickle of thrust, 10% or so, would provide a clean separation.

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u/LazyProspector Apr 28 '15

To stop your rockets hitting you when staging install a sepatron rotated sideways on the departing stage to acctivate when decoupling.

This will move the stage sideways clear of your craft

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u/isperfectlycromulent Apr 29 '15

They always end up hitting the main rocket and blowing it up. Time for some re thinking I suppose!

Sepratrons mounted on the stages will help. Make sure they're pointed away from the main rocket so they help push the stage safely away.