Gko

[AlextheBodacious]

Geostationary Kerbin Orbit or GKO is very nice. You don't move, even though you're moving. But I just use hyperedit cause it's so easy. But a quick question:

Do I needa gravity turn?

Hear me out: NASA says that you go west-east because you have the planet's momentum already, about 1,500 ish mph. So you only need maybe 15,500 mph to get 300 miles up. Plus vertical. But nonetheless, Kerbin's atmo IS unstable at times, so do I need to, or will planetary velocity boost me? This, too.

[tbarcello]

Correct answer is NO: you don't need gravity burn when using hyperedit But seriously you never NEED gravity turn to achieve orbit higher than 100 km. It's just a nice thing to do.

You DO need circularization burn at apoapsis, since without it you'll just fall back to KSC.

Actually - no, you'll fall far behind KSC, somewhere on the other side of Kerbin.

Edited August 24, 2015 by tbarcello

[FancyMouse]

I know what you mean, but remember your craft only get the surface velocity at the time of launch. So unless you can somehow get your ship immediately at the altitude, otherwise gravity will screw you up.

[Taki117]

How is Kerbin's atmo "unstable"? This sounds like poor rocket design more than anything. You should always use a gravity turn becaues it is far more efficient than trying to burn straight to your target altitude and then horizontal to circularize. In this instance, your Circularization burn is combined with your ascent to your target altitude. Planetary velocity will give you a small boost, on the order of 200m/s.

[Harry Rhodan]

But I just use hyperedit cause it's so easy. But a quick question:

Do I needa gravity turn?

Where and how would you even turn when you already edited yourself into orbit?

[mellojoe]

Kerbin is only rotating at like 250 m/s. Kerbostationary Orbit is what 1000 m/s? Going straight up from the planet's surface will still leave you 750 m/s short of orbiting and you'll fall back down.

Orbits are more about going SIDEWAYS really fast than they are about going up/down.

[tomf]

Th OP is assuming that because his rotational velocity is the same at GKO as it is on the ground he has the same horizontal velocity and doesn't need to add any more.

However if you think of the circle that something in GKO traces out in a kerbal day it is much larger than the circle that the space centre draws. Therefore the GKO orbit has a much higher horizontal velocity than KSC.

[Pecan]

Orbiting is about going around and around.

Going up and down is not about going around and around.

The ideal way to launch is by using a Hohmann transfer with your, initial, Pe at ground level (duh!) and making your Ap the desired orbital altitude as soon as possible - which means going sideways immediately. Unfortunately, of course, that doesn't quite work on a vacuum body, even if there aren't any mountains in the way. On a body with atmosphere it definitely doesn't work because of higher drag at low altitudes; but the principle is the same - concentrate on getting horizontal speed as early as possible.

As the story says - any vertical velocity is lost to gravity, any horizontal velocity you get to keep.