Under normal operating conditions it would be designed to re-enter the atmosphere nose-first since the capsule is supposed to be attached to the front of the orbiter.

Perhaps it would be optimistic to expect damage to the shuttle to be discovered while still in orbit... but if it were then the crew would have at least one way to return home (Columbia's crew would have been stranded no matter what). After the de-orbit burn the capsule would detach from the orbiter, rotate into the proper "bottom-first" orientation for atmospheric re-entry, and at the proper altitude deploy a parachute and ballute for landing.

But the BIG question is: can it pull an "emergency detach" during the hottest part of re-entry, even while the rest of the shuttle disintegrates and explodes? Good question.

I don't know. Perhaps it could have canards, or fins, to keep it oriented properly. But violent torquing from an improper detach might destroy it. Air pressure might keep it pressed against the orbiter too. It's tough under those conditions.

If the orbiter has a high angle of attack, then the best direction for the capsule to go is upward, in the same direction that an ejection seat would travel. Maybe it could fire rockets, with a very fast computer controlling them. The rockets would work very fast and hard to keep it steady in the hypersonic airflow, rotating it quickly, not too violently, into the proper "bottom-first" position.

Maybe.