Hello, After quite a bit of testing I'm sharing my launch procedure, i'm totally open to suggestions on improvement I'm using Mechjeb, as It would be impossible to accurately mantain the ascent profile by hand. Target altitude : 80 km Turn Start Altitude : 4 km Turn End Altutide : 55 km Turn Shape : about 64 % corrective steering OFF Vehicle Mass (Orbiter plus RCS fuel plus docking ports in the cargo bay plus cameras) = 40.539 t Payload Mass = 12.963 t This way I end up at MECO with an 80 by about minus 70/80 km and still 170 of dV left in the main tank I also did a "dry run" without payload, using the same parameters except Turn End Altitude set to 45 km, I obtained an 80 by minus 50/60 km orbit (the reason for setting turn end so low is that you want to gain sufficient tangential velocity BEFORE achieving your target apoapsis, so you can detach the external tank after MECO and keep it realistic whilst not wasting all your OMS fuel on circularising) . Therefore we should adjust the turn end altitude between 45 and 55 or greater based on payload weight. I still don't know how heavy a load the shuttle can carry, but I guess it could exceed 16/18 tons and still achieve a similar orbit About the Insignia : I'm aware that KSO is available, and I really love the IVA they built, I wish something like that could be done for the CSS, however I find that shuttle waaaay too small for my needs, it's impossible to fit any ISS module in there. Regards, and update soon!