A couple months ago I was reading about magnetohydrodynamic (MHD) aerobraking and thermal protection concepts over at Jon Goff's blog:http://selenianboondocks.com/2010/02/mhd-aerobraking-and-thermal-protection-part-i-introduction/http://selenianboondocks.com/2010/02/mhd-aerobraking-and-thermal-protection-part-ii-atmospheric-reentry-for-rlvs/http://selenianboondocks.com/2010/02/mhd-aerobraking-and-thermal-protection-part-iii-aerobraking-and-aerocapture/While it's obviously at quite a low TRL, the concepts seem potentially promising. Any thoughts on how useful MHD tech might be for aerobraking and reusable thermal protection? I also was intrigued by the idea in the comments that suborbital spaceflights could be a good place to test this tech.
It is more likely not viable. The energy put into the system could be use instead to slow the vehicle eliminating the need for thermal protection.
You may be interested in this 1968 Boeing proposal on Transpiration cooling for reentry -- Jon referenced it in another blog entry. It describes a phase one study of an alternative to ablative heat shields. From what I understand, there were no follow up studies.