DATABANK:
   
   
   
   
   
   
 
The arguments against powered re-entry presuppose that the fuel to accomplish this has to be borne up from Earth, which would be prohibitively inefficient and expensive, if not impossible. Once a supply of fuel can be maintained in LEO from off-planet sources, this objection is less material.

It is worth re-examining what velocities and shielding would be required to ease a shuttle down more gradually, given it could maintain onboard flight power, first from drop-tanks of fuel and oxidiser, and later in flight, by 'Sabre'-type air-breathing engines.

The GATOR Concept....