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Hello, I need help!


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Hey guys, I just recently started playing KSP, and I am having a lot of fun so far, but I have one problem. The rockets I build, while I think they are powerful enough to get into orbit, my aopsis(?) ends up being very high, and I have to burn a lot of fuel to get a stable orbit. By this point I usually don't have fuel to do anything else. Is there any tips you guys could offer me to help me get into orbit more efficently? Like when i am supposed to tilt the rocket to gain speed? Also, is there a mod that lets you plot courses and put vehicles into orbit automatically for you?

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Here's what I do:

Launch rocket. Once you get to around 10 km, go into the map view. Once your apoapsis gets to about 30km, turn to about 45 degrees. Once it reaches 45, start going even more horizontal. By the time your apoapsis reaches 70 km, you should be completely horizontal. Fire your rocket until reaching an apoapsis of about 80km. Drift the rest of the way until you reach apoapsis, and then circularize your orbit from there.

And yes, there are mods that will automatically orbit for you, but I reccomend not using them until you can get into orbit manually.

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The joys of a gravity turn....

We all went through this little learnig curve... Shooting big rockets straight up and then trying to burn side ways to get the orbit to work.

Basically you have to start turning early and often.

Launch going straight up (have asas on ...ie press 't')

at around 8-10km up start leaning over (turn off asas and move the ship to over 30-40 degrees tilt in the direction you want your orbit to be (90 for equitorial, due north for polar etc)

continue to slowly roll over towards the direction you want to go til about 35km altitude. Check your apoapsis in the ap screen (or in the orbital info screen from mech jeb) once its at the height you want for your orbit, kill your engine and float the rest of the way up. once you get near (within 10-35 secs of the apoapsis) point your ship at the horizon and burn to circle up the orbit (prolly best to use the map view here).

That is a gravity burn. Should lessen your fuel needs, and get you to your wanted orbit.

Alacrity Fitz

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One thing - specifically make your gravity turn EAST, to a 090 heading. That gives you the maximum advantage from the rotational velocity of the planet.

there are reasons to launch into a polar orbit, or even (debatably and rarely) a retrograde (west) orbit. but East is the easiest on fuel, and a great place to start.

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Get into orbit by doing the following;

1. Do the normal burn and gravity turn to 45*

2. Watch the apoapsis until it hits the desired allitude and hit x to shut down the engine.

3. Orient your space craft to the horizon on the Nav Ball and coast until about 45 seconds to apoapsis.

5. Fire the engine, watch for the parapsis marker. When it reaches the desired altitude, hit x to shut down the engine.

From there, you can fine tune your orbit by burning prograde -pointed in the direction of travel at apoapsis - to raise the parapsis, or point retrograde at parapsis to lower the apoapsis.

Doing a burn retrograde at apoapsis is the most efficient way to return from orbit. Parapsis doesn't need to reach the ground, it only needs to drop to about 20,000 meters. Kerbal's atmosphere will then slow you down the rest of the way. You can always return doing a retro burn from any place in your orbit, it will just take more fuel.

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Parapsis doesn't need to reach the ground, it only needs to drop to about 20,000 meters.

I find that 30,000 usually does the trick, if you wind up being short on fuel.

OP: Everybody else has given you the best advice in this case; the gravity turn. Straight up to 10k, then turn to 45 degrees on heading 090 (I've also heard that you can turn ten degrees per 10k and get mainly the same effect). Switch to your map occasionally to check your apoapsis; cut your burn when it's where you want it. You can either then set a maneuver node there for orbital insertion or just burn along the horizon when you get close to it (say fifteen to twenty seconds to apoapsis, depending on how much acceleration your orbital stage can provide). You can tell when you've acheived orbit by your speed at that point:

75: 2,287.4 m/s

80: 2,278.9 m/s

85: 2,270.6 m/s

90: 2,262.4 m/s

95: 2,254.2 m/s

100: 2,246.1 m/s

105: 2,238.2 m/s

110: 2,230.3 m/s

115: 2,222.5 m/s

120: 2,214.7 m/s

125: 2,207.1 m/s

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You need to preform a gravity turn. First, you need to gain vertical speed, so launch straight up as usual. Be sure not to throttle too high as drag/air resistance and terminal velocity can decrease fuel efficiency. Switch between map view and the external view to maintain awareness, but when you reach 10000 meters, or 10 km, you should begin to consider a gravity turn. If you are not accelerating enough i.e. the T/W is not very high, you may have to turn later. Your spacecraft should have some distance to apoapsis before you turn, ideally for me, your apoapsis should be ~ 15-20 km higher than your current altitude. Turn over to 90 degrees at a 15 degrees down ( just tipping over past the first angle mark) and add horizontal velocity. To me, it has been experimental and it is all about the "Feel", but soon you should turn to 45 degrees, than almost on the horizon before you reach the vacuum. Be sure to reach your desired altitude, but your apoapsis will still rise when burning only horizontal. Depending on how high your T/W is, (Just how quickly it can accelerate to be simple) you may want to start burning to create an orbital trajectory 1 minute or 45 seconds before apoapsis. I hope this was not overly complicated, but good luck! It just takes time to perfect after you get the hang of it.

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Also, is there a mod that lets you plot courses and put vehicles into orbit automatically for you?

Yes, there is a mod. MechJeb will auto-pilot your ascent. You can choose the altitude of your final orbit, have it auto-stage, change the profile of your ascent, including when your gravity turn starts, etc. It's actually not a bad idea to watch MechJeb do an ascent to get an idea how it works. And of course, after you've done about 20 ascents, they get pretty boring. I manually pilot about every 10th now or when I'm launching a new rocket just to keep in practice, but MechJeb does all the rest for me.

Here's a link:

http://forum.kerbalspaceprogram.com/showthread.php/12384-PART-0-20-Anatid-Robotics-MuMech-MechJeb-Autopilot-v2-0-8

I recommend getting the latest dev build; there are some bug fixes there that are nice to have.

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