HRO shuttles, originally designed for some advanced levels of STS challenge, now join together for even more daring mission than before   Launch sequence First is HRO-M03 with all the deployable vehicles. Including the Elcanoplan 2 strapped on its back Barely enough thrust for takeoff (and that's with payloads having the tanks practically dry). I even activated the main engine of the Elcanoplan, but that didn't seem to make much difference either. Those booster