sorry this has been debated to death, but i can't get a definitive answer. so, everywhere i read LKO+Oberth is the best way to get out of kerbin's SoI. the reasoning behind this is while going straight up the rocket has to fight gravity for the entire trip. however, your doing the exact same thing when gaining orbit, just in a different direction, to get a "constant fall", and increasing apoapsis is fighting gravity so you fall back to the planet. i decided to do some testing to see which method will have the greatest effect on the sun's periapsis and deltaV at escape. same craft in each test relevant mods: NEAR and kerbal engineer redux(for the data) 1+TWR 6405 total DV 400SI engine a few small wings to keep foreword here are the results target was lowest sun periapsis. LKO to escape DV at escape 1881 sun periapsis 5 300 042 585 (after all fuel was used) note: i had to burn several times in lko, all at periapsis. straight up DV at escape 1671 sun periapsis 3 041 693 328 383 (after all fuel was used) i am by no means a expert, or even an enthusiast space engineer, but both results are fairly similar. with the straight up approach sacrificing some deltaV into lower periapsis. the straight up method has it's drawbacks, needing 1+TWR for the entire burn and you cannot rendezvouses with other crafts. the LKO+Oberth method is interesting compared to straight up, i had more periapsis, and more fuel after leaving kerbins SoI. LKO+Oberth is much more complicated to get out of kerbin's SoI, needing several precise burns at just the right time to be effective. then there's the difficulty of getting orbit. many steps that need to be done with little room for error (which is bad in any situation). i prefer the straight up method for it's simplicity. since im burning at the suns AP or PE from the start. just for kicks, i decided to do LKO+straight up, gaining 1 000 000 altitude, then starting my orbit maneuver followed by a escape maneuver. sun periapsis 7 748 530 240 DV at escape 1481 these results are probably skewed by my inexperience, as i got frustrated by LKO+Oberth very early on and started shooting straight up instead. can anyone else post results? this is the only one i could find, from reddit: voneiden Actual research results: 3 stage craft. Each stage burns for 70 seconds. 1) Standard launch. At 10km, tilt 45 degrees east. Circularize at ~100-125km. Burn everything left and coast to escape. v∞ = 5037m/s. 2) Launch straight up. UP UP UP. Coast to escape. v∞ = 5112m/s. Conclusions Delta-v was probably lost in case 1 due to slight burning to assist in vessel rotation. As such, I conclude both methods to be equal in their efficiency. Method 2 suffers from burning at high altitude, while method 1 suffers from the extra cost of circularizing (but gains boost from lower altitude final burn). Low thrust vehicles should stick to method 1 so they can benefit from oberth effect. High thrust vehicles might wanna stick with method 2.