On board Quartz Rate Sensors, silicon micromachined accelerometers and valves operate a miniature reaction control system for course correction and rendezvous. This would obviate the need for the flat spin idea above. This is a difficult system to properly model. The pulsed nature of the aerodynamics in the ground reference frame makes time invariant solutions suspect. The radial variation of density and specific heats disallows ordinary heat diffusion equations.
Aerothermochemicaldynamic effects add their own non- linearities, as does radiative energy transfer.
The rarefaction should allow better performance than this, however the additional heating incurred may offset the gains. In addition to the unanswered technical issues, there are the usual items of environment, politics and finance.