Complete idiot's guide to making orbit?

[Cranium]

I'm fairly new to rocketry, and I've been looking around for a good tutorial that just tells me the basics of making orbit, for example what kind of speeds are optimal in lower atmosphere, when to start your g-turn, and what kind of limitations there are.

So far, I just hear some pretty basic and non-specific things, like starting your g-turn around mid-atmosphere, and that the faster you go, the less efficient your rocket may be in lower atmosphere.

What I would like, is some fairly specific things, giving me an absolute fail-proof way to get just a basic rocket into a stable orbit. Bonus points can be awarded for someone who can explain the mechanics of getting a spaceplane into orbit and beyond as well.

[falofonos]

may be of help

[Flixxbeatz]

Simple.

1 - Launch

2 -

3 - PROFIT!

[Scrogdog]

Here's a great resource for beginners and contains both written work and videos, whatever you prefer.

The Drawing Board

You'll find that there are some basics to learn, but different configurations may require modified ascent profiles.

[Uberick]

Effectively, start your turn at 10km. this is the point at which the atmosphere becomes so thin that gravity becomes more important than drag. At this point, you start to turn East(90 on your nav ball). Make the turn gradually, just "tipping" your rocket to the 90 degree side. Let your prograde marker slowly slide down to the 45 degree mark(45 degrees pitch, not 45 degree heading. You still want to aim 90 degree East the while time, and slowly tip over until you are 45 degrees "tipped over" to the horizon.). After your Apoapsis gets around 45-60km, let it drop the rest of the way to the horizon at keep firing at 90 until you establish the apoapsis you want(70km is the minimum to NOT hit the atmosphere)

Once you have the apoapsis you want, place a manuever node there, and drag it until it encircles the planet, and creates a Periapsis as close as possible to your current apoapsis(lets say 80km). Once you do that, a blue dot will show up on your nav ball, and to the bottom right of the nav ball, a timer will show up showing you how long you will have to burn for, and how far away it is. If you complete that burn, you will circularize your orbit. Congrats!

One note though, if the burn is, for example, 20 seconds, you want to start your burn 10 seconds early. (half the time) You do this because the manuever node assumes that you are adding all your speed(Delta v), INSTANTLY. Obviously, you cannot do this, so you must try to average out the speed you add; half before the node, and half after.

As far as going too fast in the lower atmosphere, that is due to terminal velocity, which is determined by the drag of your vessel and the density of the atmosphere. there are tables out there for terminal velocity of Kerbin, but I don't have them in hand(will look). As a rule of thump, you want a thrust to weight ratio of 1.7 on most of your rockets, that will usually keep you below terminal velocity. If you really want to be precise, get MechJeb, that will tell you the terminal velocity at your current altitude, so you can always be most efficient.

I've got a class, but hopefully someone else will put up more data:) If not, I'll put up pics and a solid guide later tonight!

Here's a ship to base off of,

Welcome to KSP! Happy Launchings!

[Flixxbeatz]

On a serious note, watch this, and take note of the altitude, navball, and the heading of the rocket. You might easily learn a thing or two.

Don't mind the fuel transferring and extra engine protocols, though...

[Bobiii11121]

Launch rocket and wait till you go up in 10,000m from the ground, then turn on the half of the blue thingy and fly, use M to see your orbit

[Flixxbeatz]

Launch rocket and wait till you go up in 10,000m from the ground, then turn on the half of the blue thingy and fly, use M to see your orbit

Better yet, control the rocket from the orbital view once you've got past the 10-km mark by bringing in the navball. Now you can control your rocket while simultaneously checking your current heading and situation. Talk about multitasking

[Rickenbacker]

Simple rules of thumb:

Look at the navball every time you maneuver, NOT at the rocket.

Get it up to 10.000m, and try to keep the speed below 200m/s until you do.

Once at 10.000, tilt it to the east (90 degrees on the navball) 30 degrees or so (60 degrees above the horizon).

Look at the map, when your apoapsis is as high as you want it (at the very least above 69.000m, preferably closer to 80 to have som margin), shut off the engine.

A short while before you reach apoapsis, point your rocket prograde and burn, look at the map, and wait for the periapsis to rise up to match the apoapsis (approximately).

You're in orbit!

Not the most efficient way to do it (that would be a continuous burn where the rocket starts to turn at 10K, and follows the prograde marker more or less all the way up), but simple and works every time.

[Cranium]

Alright, so this all helps me.

In general from what I can see, I want to start my g-turn at aroung 10km, keeping my speed around 200m/s until then to avoid large amounts of drag. Once my apoapsis is where I want it, I cut my engines, and coast. I can then make a maneuver node at/around my apoapsis to make a nice, circular orbit. From that point, I should be in a position well over the planet, observing the silly little men scurrying around.

I do have one question however, what kind of height would I want to go for if I were to put a space station in orbit? I have heard that the lower your orbit, the faster you need to go, and not all crafts can make those speeds. So should I make a higher orbit, like something around 300km?

EDIT: and when I start my g-turn, it should be gradual, since that is the most efficient for fuel, right?

[Uberick]

The atmosphereic drag chart is on the wiki @ http://wiki.kerbalspaceprogram.com/wiki/Kerbin Lots of good information there.

There are a great many ways toget to orbit, you'll read alot of things on the forum about the "right' way to do it, and the "wrong" way to do it. Don't pay attention to those yet. Alot of the people who've been playing this game for a while will discuss the best way to achieve an objective, but when you're just starting out, you only need to worry about achieving the objective in the first place. The "perfect" ascent path is a complicated thing to find and execute. The good news, is that you won't waste that much delta v if you're off by a few degrees, or follow "rules of thumb" rather than hard math.

Don't worry about bringing too much fuel, or overbuilding. Overbuild everything! AS you play, you will become more familiar with what you need to get stuff done.

[BaneOfPilots]

Okay. Build a rocket capable of reaching orbit. When you launch, start turning the direction you want your orbit to be around 5000 meters - 10,000 meters. After you start the "gravity turn", look at the map until the AP reaches the altitude you want it to be. When it reaches your desired altitude, fast forward to the AP and burn prograde ( Green circle on NavBall). The PE should come out soon and you have an orbit!

[SixthFall]

as far as good heights for a space station, its all preference really. try to shoot for something like 90-150km for a start. (I personally put my stations in keosychronus orbit, but thats almost 3000km 0.o)

[Uberick]

Alright, so this all helps me.

In general from what I can see, I want to start my g-turn at aroung 10km, keeping my speed around 200m/s until then to avoid large amounts of drag. Once my apoapsis is where I want it, I cut my engines, and coast. I can then make a maneuver node at/around my apoapsis to make a nice, circular orbit. From that point, I should be in a position well over the planet, observing the silly little men scurrying around.

I do have one question however, what kind of height would I want to go for if I were to put a space station in orbit? I have heard that the lower your orbit, the faster you need to go, and not all crafts can make those speeds. So should I make a higher orbit, like something around 300km?

EDIT: and when I start my g-turn, it should be gradual, since that is the most efficient for fuel, right?

As far as stations go, the lower they are, the easier they are to get to(less fuel), and, if you start a burn from a lower orbit, you will get more energy out of the fuel(lower orbits have more energy). Thus, if you have a refueling station that you use to top off your ships before they do a transfer burn, put it as low as possible.

Interesting side note, it's easier to dock ships the higher the orbit is, because they will "rotate" less because a higher orbit has less curve for a given distance. Some people care about this, some don't.

In regards to gravity turn; you want to make it gradual, yes. If you point the nose too far from prograde, you will waste energy, because you are firing your engines at such an angle that it isn't properly adding the speed to your current vector. This is called "Steering Loss". To minimize this, try not to put the nose of your craft much farther than the edge of the prograde marker. Give it just enough to turn.

Hope this helps:)

[Arran]

Simple rules of thumb:

Look at the navball every time you maneuver, NOT at the rocket.

Get it up to 10.000m, and try to keep the speed below 200m/s until you do.

Once at 10.000, tilt it to the east (90 degrees on the navball) 30 degrees or so (60 degrees above the horizon).

Look at the map, when your apoapsis is as high as you want it (at the very least above 69.000m, preferably closer to 80 to have som margin), shut off the engine.

A short while before you reach apoapsis, point your rocket prograde and burn, look at the map, and wait for the periapsis to rise up to match the apoapsis (approximately).

You're in orbit!

Not the most efficient way to do it (that would be a continuous burn where the rocket starts to turn at 10K, and follows the prograde marker more or less all the way up), but simple and works every time.

Strange enough i tend too start rotating too 80 degrees pitch at soon as possible (around 150m/s roughly) now that i feel more confident enough too leave mechjeb at home, then at 4km i tilt it over too 70/60 degrees, depending on type of rockets, and let it climb from there too 30km, and going then prograde as soon my speedmeter shows Orbit. Somehow with FAR on i seem too keep more fuel in the end, and a higher speed As compared how i did it before by Mechjeb acent autopilot, which required somehow alot more fuel and trust too get into orbit..

My rockets can now be smaller and thus lighter and faster, dont ask me the math behind it, i have no idear, i just have the numbers on speed and fuel left in my tank as reference, and its effiecenter as MJ's launches. (i have no clue on the why, i just work from trail and error)

Rockets i never could make too the mun with MJ on the helm, now easely can reach even Minmus.

But i tend even too neglect too get into orbit first on kerbin, and go straight for the mün (where i have a kethane supplied refill station for refuelling my rockets for interplanetairy missions)

[Anglave]

You've definitely got the right idea.

Any orbit above 70k should be stable, but I normally shoot for between 75 and 90k. A space station could reasonably be in a 100k circular orbit. Or you might want it in a geostationary orbit, which would be all the way out at 2,869 km.

Regarding the rate of your turn - optimal is hard to figure. It'll be a gradual turn that adds horizontal speed to your trajectory as soon and as much as possible, without keeping you in the atmosphere too long. If you turn too early or too sharply, you'll waste a LOT of thrust pushing through atmosphere horizontally. If you turn too late or too slowly, you'll be adding vertical thrust that's not really doing you much good in the sense of achieving an orbit.

Generally I turn to 45° at 10km or just after (depending on staging). Then I keep that heading until above 30km, after which I angle toward the horizon (still along the 90° line), keeping the nose just a few degrees above the prograde marker.

Just before you reach your apoapsis (which is the height of your desired orbit), turn so your nose is just below the horizon line (about as far below the horizon as your prograde marker is above the horizon) and thrust. This is the part where experience helps. Your angle and timing will depend on your craft's Thrust to Weight ratio. But generally, if your apoapsis falls, you're aimed too low, if it rises you're aimed too high. If it moves away from you in time, you're thrusting too hard or too soon.

Ideally, you'll want to keep your apoapsis from changing very much in height, and keep it just out in front of your ship (10-30 seconds seems about right) until your periapsis raises on the other side of your orbit to the same altitude, at which point they'll "flip" and you cut the engines in a nice circular orbit. Which takes practice.

Edited June 5, 2013 by Anglave

[Cranium]

Well tyou guys have all helped immensely. I think I can make a much better orbit now!

[Cranium]

Oh, and just to add while I'm here...

What's a good way to get a spaceplane in orbit? I know that you need LOTS of air intake if you're doing it on mostly jet power, but is there a general rule of thumb for making a spaceplane orbit?

[Uberick]

Spaceplanes are a pain. . . I only built one to say that I did it.

Three intakes per engine works pretty well. You want to gather as much speed as you fly up to the point where the jet engines won't work anymore; take a nice, gradual climb. Then, shut off all your jets(set them to an action group), and burn rockets the rest of the way. Once you're in orbit, it helps to have a station to dock at and refuel, otherwise you'll usually only have enough gas to maybe head to the moon,

The trick is getting the whole thing weighted and balanced properly. It has to be flyable, as well as meet the T/w ratio and d/V requirements. There are some good videos if you search youtube, but I recommend trial and error:)