Is is possible to make an orbit when launching from Kerbin that's going the other way?

[InF3RNo]

Hello, I've been told always that to make an orbit around Kerbin I need to burn up 'til 8km-10km and then burn 90-45 until the apoapsis grows to 70, then when going near the apoapsis, burn prograde to the orbit velocity, then you'll get an orbit around kerbin.

My problem is some contracts ask me to go below/above places that are just in the other way the orbit normally goes. Is possible to go up instead of 90-45, 90-90+45 and do a contrary orbit or this goes against the law of physics or something like that? I'm noob yet and not really good with science, hehe.

Regards,

InF3RNo.

Edited January 1, 2015 by InF3RNo

[SRV Ron]

Instead of turning East during your orbital turn, turn West. It will take a bit more Delta V since you lose the effect of the rotation during launch.

The only reason for the 8 to 10km straight up burn is due to KSP implementation of the atmosphere. I do that using SRBs. Then, start and continue the turn gradually until your apoapsis reaches the desired altitude as you get close to horizontal, cut power, get horizontal to the horizon just prior to hitting apoapsis, and burn to orbit. The key is the gradual turn in order to avoid undue stress on your ship or having it flip ends unexpectedly.

[ghpstage]

The reason to turn East is due to Kerbin's rotation giving you a starting velocity in that direction. At 174.6m/s its quite a lot too.

If you turn East that rotation cuts the amount effort you need to achieve orbit. But if you turn West then you will need to add twice that speed to your burn to achieve orbit, once to get rid of it, and once to make up the missing speed!

So yes, it is possible. Its advised against in general because its very inefficient for achieving a typical orbit.

Edited January 1, 2015 by ghpstage

[AlexinTokyo]

It's less efficient if your only goal is to get into orbit. That is, any orbit at all will do.

It is a lot more efficient for getting into specific orbits (like for satellite missions) than getting into an equatorial orbit and then changing planes for the required orbit.

[PB666]

The reason to turn East is due to Kerbin's rotation giving you a starting velocity in that direction. At 174.6m/s its quite a lot too.

If you turn East that rotation cuts the amount effort you need to achieve orbit. But if you turn West then you will need to add twice that speed to your burn to achieve orbit, once to get rid of it, and once to make up the missing speed!

So yes, it is possible. Its advised against in general because its very inefficient for achieving a typical orbit.

If you use MechJeb then add 174.6 x 2 delta-v to the orbital burn stage and add additional thrust to the launch stage to compensate for the added fuel weight. The launch phase to 36,000 meters is all but identical to an 090 heading (except the 270 heading on the gravity turn). Between 32,000 to 36,000 meters lower the pitch more heading west bound, otherwise the prograde angle at 36,000 meters will be higher than the trip heading eastbound and the gravity turn will be delayed and the orbit more eccentric than planned.

Note that some elevation in apoapsis at 36,000 may be desired, because at 36,000 meters your omega-squared radius will likely be lower, this means effective gravitational force will be higher during the early part of the orbital burn. Because of this one might want to add more thrust to carry the weight and compensate for the loss of delta-v, and you will want to max that thrust during the 32,000 to 36,000 turn west burn.

[Dragon7722]

Instead of turning East during your orbital turn, turn West. It will take a bit more Delta V since you lose the effect of the rotation during launch.

The only reason for the 8 to 10km straight up burn is due to KSP implementation of the atmosphere. I do that using SRBs. Then, start and continue the turn gradually until your apoapsis reaches the desired altitude as you get close to horizontal, cut power, get horizontal to the horizon just prior to hitting apoapsis, and burn to orbit. The key is the gradual turn in order to avoid undue stress on your ship or having it flip ends unexpectedly.

This is the most inefficient way of reaching the orbit... You just don't wanna do that.

You should start burning straight up to 7500+-2500km and then start your turn. Then you turn slowly and slowly towards the horizon building up more and more speed until you reach your desired apoapsis height. Then you fast foward to your apoapsis and burn there to raise the periapsis out of kerbins orbit (70km+).

[numerobis]

This is the most inefficient way of reaching the orbit... You just don't wanna do that.

You should start burning straight up to 7500+-2500km and then start your turn. Then you turn slowly and slowly towards the horizon building up more and more speed until you reach your desired apoapsis height. Then you fast foward to your apoapsis and burn there to raise the periapsis out of kerbins orbit (70km+).

How does your description differ from SRV Ron's?

To the OP: in order to launch into an orbit of inclination X degrees, when you start your turn, point to an orientation of roughly X+90 degrees, then just follow the heading of the prograde marker. So if you want zero inclination, you fly due East; 180 inclination, you fly due West; 45 inclination, fly North-East.

That works because at the equator, so whatever direction you're going, that's the direction your orbit inclination goes (except zero inclination means East, whereas zero heading means North). You start at the equator. When you aren't at the equator, the correspondence is more complicated, so just keep flying prograde and you don't have to solve equations during launch.

I'm eliding one little detail: you need to burn a bit West of what I said because you have to cancel your starting orbit speed of 175 m/s.