Noob Question

[JoeD]

I have been playing KSP for a while now and i am loving it but I am burning a ton of fuel to get into orbit. I have noticed that when i turn over to 90 at 10 km the prograde marker dips below the level indicator. If i try to chase the prograde it will dip below the horizon line and i will begin to fall. Can anyone tell me how to fix this? is it my flying or a trait of the rocket?

[Aphox]

90 degrees is fully horizontal (the horizon line on the indicator is actually 0, while 90 is straight up). You want to be pointing at 45 degrees. Generally, during my ascents, I begin to slowly tip toward the horizon, and depending on my rocket design, end up fully horizontal at 35-50km, depending on the design of my rocket.

The prograde marker just points to where it would be most efficient to enlarge your orbit by increasing the periapsis. At low altitudes or speeds, the thing goes crazy and tells you to point in all sorts of directions.

Try sloping at 45 degrees and staying there until your apoapsis reaches a decent height, something like 30km or so, and then slowly begin to tip toward the horizon line to gain horizontal speed. You'll get the hang of it.

I might be misunderstanding your situation though; let me know if I am. I feel like 'turn over to 90' might be talking about pointing eastward. In which case, you might have other problems.

Edited January 28, 2014 by Aphox

[Champ]

I have been playing KSP for a while now and i am loving it but I am burning a ton of fuel to get into orbit. I have noticed that when i turn over to 90 at 10 km the prograde marker dips below the level indicator.

What happens is pretty simple :

You are pushing horizontally, gravity is pulling vertically. This adds and give you a prograde vector that is something in-between.

If i try to chase the prograde it will dip below the horizon line and i will begin to fall. Can anyone tell me how to fix this? is it my flying or a trait of the rocket?

It will always be like that, nothing to do with your flying or your rocket. You want your prograde vector to be horizontal ? then you should turn at a little less than 90 degrees. Just don't "try to chase the prograde" : try to set it.

[neoaikon]

How fast are you going at 10km? And are you viewing the surface or orbit velocity. A prograde marker dipping slightly below the horizon in surface mode is OK, as you'll eventually gain enough horizontal velocity to raise it again. In orbit mode it's bad because it means you've passed apoapsis and are now descending, and you'll need to start burning more radially to compensate.

[bowfonz]

Just don't "try to chase the prograde"

This is a good tip. The prograde indicator is not like the node indicator where you point and burn. It's simply telling you what direction your rocket is moving. You won't have the nose of your rocket pointing at prograde in most situations.

[Xiphos]

If you need a video example, click the link in my sig. I show you how to fly a ship to orbit and where to turn, what to do, etc.

[radonek]

I bet you got advice to "turn to 90°" and this is just misunderstanding. This signifies 90° mark on navball, which points to east (to steal some delta-v from planet rotation). Do not turn your ship horizontal, turn it about 45° from vertical – in direction of 90° mark. You only turn horizontal when you get out of atmosphere.

Imagine it as a compromise trajectory. Best would be to accelerate straight up, to get off atmospehere as fast as possible, but youd end with very little time to actually attaing orbital speed before falling back to well. Other best would be to just start horizontaly and only work on orbital speed, but air friction will rob you. (This is first phase of most SSTOs actually.) So, you do both – start straight up to get out of thickest air, then pitch a bit to get some orbital speed while still speeding up. You don't get much of a real orbital speed this way, but you get on flat balistic trajectory that should give you enough time outside atmosphere to do some real speeding.

Of course, in reality this is not so pronounced, all phases blend into each other in a complicated curve. Kerbal receipt "10km up, turn east, 60km up, turn horizontal, run like hell" is just good enough aproximation.

[KSK]

Page 17, figure 9 shows the launch trajectory for the Saturn V. Doubt it's strictly to scale but it should give you some idea. I never knew about the coast phase before third stage ignition either - it tends to be the way I do it in KSP but I never realised that's how it worked for Apollo as well.