This is my best with stock engines and scaled to the tower: http://users.ecs.soton.ac.uk/prb/junk/spess/Thor%202%20Quad%20Mk3.craft Uses the 3rd party 1-to-4 and escape booster parts, and is currently 15,000,000M out doing 1.3KM/s because I am bad at plotting orbital trajectories. It'll go straight up at full throttle with SAS on to 100KM and still give you a half-full-tank quad-liquid stage and a full single-liquid orbiter with an escape thruster as a last resort. (Or to 10KM with a two-tank quad.) It's predecessor is interesting in that it's such a tempramental little bugger---it works pretty beautifully so long as you do all the right things at the right time, otherwise it fails explosively: http://users.ecs.soton.ac.uk/prb/junk/spess/Thor%20Duo%20XL%20Mk2.craft User Manual: - Turn on SAS and don't turn it off until the ship is down to the last two liquid stages unless you like large explosions. - Time the launch for when the top of the ship is not wobbling toward the launch tower. - Take off at default throttle only. If you raise it, it'll rip itself apart. If you lower it, it'll unsteadily topple into the launch tower. - Throttle up gently to full once clear of the tower, else the solid engines will run dry too far in advance of the liquids and it'll falter badly during the climb. - Never ignite a stage before the previous one is clear. There's enough debris ejected that the explosions will cook off the fuel in the stages still attached. This is a very pretty chain reaction but somewhat outpaces the rate at which you can skip ahead to ejecting the command capsule. - The capsule separation stage has an escape thruster. Its function is to drive the pilots violently into the ground when the rocket turns upside-down. If you run out of fuel in space it is also your last-ditch hope for a de-orbit burn. - If you modify anything, you need to move the chute back up the stage list to the top, else it fires too early and is destroyed by the escape thruster. Follow these simple guidlines and you too can have many happy hours of drifting helplessly through the featureless cosmos in the remains of your Thor Duo XL Mk2.