[wyattearp]

If the tank were to be attached from the opposite side, on the shuttle "back", the danger would be much less.

Except that there isn't any structure there that can handle that kind of a load, or anywhere near that kind of a load. There would also be a huge balance problem.

[GSlob]

For balance problems - I was under the impression that shuttle engines are vectorable. Attachment support would have to be engineered in.