take-off is really a non-issue. military has used rocket assisted takeoffs for a long time. but the deceleration/descent motors you would have been specially designed and built to fire a perfect amount of thrust for the right amount of time and would have had to put the aircraft in a certain flight regime (altitude, airspeed, etc) to initiate rocket assisted landing. since they intended this with a very specific mission in mind, its not surprising at all. its a matter of "what can i do with what i have" instead of "what do i need to build to do what i want". both are valid approaches to design something like this, and the former is what you default on when there is a time constraint.