I may be off here,but I seem to recall that that thermal and structural stresses on the shuttles could be significantly reduced by an s-turn free re-entry profile.

Again, I may be mistaken, but I seem to recall that the s-turns were put in place back in the bad old days, to keep the landing shuttles out of SOVIET and Chinese airspace, and to have the re-entries entriely in US airspace.

Times have changed, to say the least. Russia is now our partner in ISS, and China is planning a manned launch soon. Certainly, if my memory serves me correctly as to stresses, use of their airspace should not be a problem if there was a recognized emergency situation - I'm fairly certain we would extend the same courtesy to China, should the need arise.

There may already be limited agreements in place, if I recalll correctly...

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