How Would you get this Kerbin Orbit?

[Roady1976]

Hi All.

I have been banging my head against my desk, trying to achieve an orbit around Kerbin for one of my missions. I know how to get an orbit, i can get to (and land on) the mun / minmus (just so you get an idea of what kind of level i am at). But this particular manoeuvre has gotten me stumped!

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Every time i try to achieve this orbit, i am constantly running out of fuel, because of extreme burn times. I am sure this should be easier that i am making it. I have tried matching AP / PE and then performing a plane change.

Tried Different launch orbits.

I am normally one to figure it out by myself, but this one just has me stumped. My Rocket is probably overkill but as it stands, my answer is to throw moar boosters at it for more DV. But Alas i am pretty much at my weight limit for the current VAB.

Any suggestions on the best way to approach this?

Thanks for reading and time.

(i hope this post is in the right place)

Edited June 8, 2015 by Roady1976

[n0xiety]

Launch when the requested orbit is right over you and it should be like any other launch. If you miss the inclanation due to the requested orbit being really close to kerbin it will take big numbers of dV to fix it. So launch as close as you can.

[Meecrob]

Quick answer - someone will surely expand on this. To lower dV for plane changes, align your AP with either descending or ascending node, increase your AP to something huge to lower orbital velocity, then make the plane change.

Edit to add: This is the easy way, not the proper or realistic way.

Edited June 8, 2015 by Meecrob

[Kryxal]

Put together a rocket with maybe 5k delta-v and launch directly to something close to the proper inclination. This will require that you launch when about to pass under the orbit, go fairly close to due north/south, and pay attention to the direction of the orbit on the map view when you do.

[n0xiety]

Quick answer - someone will surely expand on this. To lower dV for plane changes, align your AP with either descending or ascending node, increase your AP to something huge to lower orbital velocity, then make the plane change.

It will still take a considerable amount to change inclanation even with that method. Atleast 1200-1600 dV if he launches to 0 degree inclanation. Don't forget that he has to lower his AP after increasing it and making the inclanation change to match the orbit.

Edited June 8, 2015 by n0xiety

[Yasmy]

I prefer to do everything Kerbaled if possible, but if you are having delta-v issues, why take a command pod for an unmanned satellite contract? Use a probe body. If your burn times are too long, you may have design problems.

But you should definitely launch into an inclined orbit. Try to launch into an orbit within 5 degrees inclination of the target orbit. You have to wait until KSC is near the ascending or descending node, and launch at the correct angle (adjusted slightly for Kerbin's rotational speed). You should have enough delta-v with your current vessel.

Edit: Multiply ninjaed!

[Roady1976]

Thanks all, i didn't even think about the planet rotation, when doing a launch!

Thanks for the help

[georgTF]

Launching into inclined orbits when KSC is under/over the plane of the orbit is indeed a nice solution. Personally those are not the hardest satellite contracts. The absolute worst for me are sat orbits that are too close to another body, usually the Mun. Getting the orbit without getting collected by Mun's SOI seems to require both timing and patience, and those things are sometimes in short supply with me.

Anyway, for anyone struggleing with Kerbin system sats, here is a powerfull yet cheap solution. It can easily be fitted with a return capsule for manned missions although at a cost of some DV. I'm thinking Mk1 capsule + small tank + small orange engine would be heavy enough compared to the mass of the sat. Might even be better to use the Ant engine. Then again, the craft is overkill for simple equatorial orbits on Kerbin or the Mun. You might not even ditch the 909 engine unless you have some oddball retrograde, inclined orbit requirement.

The craft as is, is mostly made up of fuel and gains efficiency as it sheds fuel/mass. I haven't tried it, but a Duna mission may be possible. Though it's mainly designed as a all-in-one solution for ANY orbit in the Kerbin system. Simply tack on whatever science bit is required by the contract and lift. Base cost is around 10.000. Enjoy.

Craft link: Sats Done Cheap II

NOTE - Start pointing to the horizon immediately after launch. The Kickback booster accelerates so hard that you'll only reach about 60 degrees before supersonic drag makes steering difficult. At that point let the booster burn out, wait for the flames to die down a bit before breaking the protective shell. Once high enough and slow enough not to suffer overheating (it all happens very quickly) break the shell and stage the orbital engine. Complete the coast to Apoapsis and circularisation at your leisure, then go wherever the contract tells you to.

NOTE 2 - Allways keep a solar panel facing the sun once in space.

Edited June 9, 2015 by georgTF
doh

[DeMatt]

Anyway, for anyone struggleing with Kerbin system sats, here is a powerfull yet cheap solution. It can easily be fitted with a return capsule for manned missions although at a cost of some DV. I'm thinking Mk1 capsule + small tank + small orange engine would be heavy enough compared to the mass of the sat. Might even be better to use the Ant engine. Then again, the craft is overkill for simple equatorial orbits on Kerbin or the Mun. You might not even ditch the 909 engine unless you have some oddball retrograde, inclined orbit requirement.

The craft as is, is mostly made up of fuel and gains efficiency as it sheds fuel/mass. I haven't tried it, but a Duna mission may be possible. Though it's mainly designed as a all-in-one solution for ANY orbit in the Kerbin system. Simply tack on whatever science bit is required by the contract and lift. Base cost is around 10.000. Enjoy.

http://i.imgur.com/LGoU0lzm.png

NOTE - Start pointing to the horizon immediately after launch. The Kickback booster accelerates so hard that you'll only reach about 60 degrees before supersonic drag makes steering difficult. At that point let the booster burn out, wait for the flames to die down a bit before breaking the protective shell. Once high enough and slow enough not to suffer overheating (it all happens very quickly) break the shell and stage the orbital engine. Complete the coast to Apoapsis and circularisation at your leisure, then go wherever the contract tells you to.

NOTE 2 - Allways keep a solar panel facing the sun once in space.

A couple suggestions... move the fairing base to on top of the FL-T400, so it only encloses the satellite proper instead of including the orbital engine - you can stage it at the same time if you want, or after switching to the orbital engine; either way, it'll help with cost and mass. Also, if you find the Kickback punting you too hard in the lower atmosphere, right-click it in the VAB and tweak its thrust down. On a fairly similar launcher, I set mine to the 65% range.

[Streetwind]

If you place that fairing base higher, your second stage needs to carry it all the way even after the fairing itself has already been staged. By putting it below the orbital stage, it gets dropped all at once.

Both variants can have their advantages. It's a tradeoff between the effect of the enlarged shell on the first stage's fuel-mass-fraction and the effect of the fairing base on the second stage's fuel-mass-fraction, and it depends on the exact vessel which of the two saves you dV over the other.

[selfish_meme]

Go higher, changes are hard in low orbit, go high and then cone down

[georgTF]

The idea was indeed to ditch the fairing along with the booster into a suborbital trajetory and avoid lugging it around. The rocket is overpowered already so the weight penalty is small enough to be irrelevant. The smallest fairing doesn't increase in mass with size quite as much as the medium and large ones do.

The criticism is fair though because i intentionally didn't optimise it for efficiency, but rather went for a "Phillip J. Fry" approach of completing satellite contracts in the Kerbin/Mun/Minmus system as lazily as possible regardless of wheter they're easy or complicated. Load craft, fly into position, lose a drinking contest with the autopilot, profit.

It's also possible to double or triple stack satelites inside the fairing, if you're lucky enough to get contracts with similar orbits.