What is the smallest craft that can make kerbin 100km orbit? Looking at old threads nothing super small works anymore. Did some tests with mechjeb auto asscent. Built a simple rocket. Don't know if it has enough delta v to make 100km orbit -- haven't made it yet Aero spike, 4 winglets, 4 T400 fuel tanks, small ASAS, and small 1 man capsule. Fired the rocket straight up and jeb reported 2k m/s loss to gravity. 860m/s loss to drag. basically best case for drag and worst case for gravity. Tried various other trajectories and closest I have gotten to 100km orbit is 100k apo ~ -62k per. I believe those accent path settings were 6, 70, ~50% slider (1 sliver of black above the final red bar). 4416m/s delta v expended. 976 lost to drag, 1370 lost to gravity. Edit: Got periapsis down to -40k with better turn finish altitude. Spend more time burning in orbital prograde. Ran a bunch of launches and did a little manual binary search on end turn altitudes. Found 48.5 provided the max benefit with the curve adjusted to have the last full red segment (upper right) shown fully. Moving slider right begins the flat line along the top. Sliding it left flattens the curve and induces a lot of steering error. Starting altitude may note be ideal, but it feels pretty close.