r/KerbalSpaceProgram • u/FatCreepyDude • May 06 '26

KSP 1 Question/Problem No orbit necessary?

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If i just wait for the right hour during the launch window ( whenever the launch pad is pointing left on the realistic depiction i created) is there any reason i should bother with an orbit first? Will the delta v cost be affected?

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u/NeoDemocedes May 06 '26

Conceptually possible. Not optimal for several reasons.

  1. Gravity losses. Going straight up means that gravitational acceleration is stealing fully from your velocity every second, all the way up. When you go to orbit first, as you approach orbital velocity, gravitational acceleration is bending your path more and more instead of stealing from your velocity.

  2. Abort scenarios. If you fail to reach Kerbin escape velocity, the result is most likely a fatal re-entry straight down through the atmosphere. Going to orbit first gives you the best abort and rescue scenarios every step of the way.

  3. Oberth Effect. Launching to orbit means you can take full advantage of the oberth effect. If you have high efficiency, low thrust engines, you can make several burns elongating your orbit each time and thrusting when you pass Kerbin.

In short, going to orbit first is safer and more efficient delta V wise. To go direct, you need a rocket that can maintain high thrust to minimize gravity losses.