Space plane question and response

Just one question: Since the craft is designed for trips into the upper atmosphere to the edge of space, a possibility exists that it could (by whatever means) cross that limit and end up outside the atmosphere.

In such a case, jet engines would be useless due to the lack of oxygen to burn fuel (which could also occur in high atmosphere).

What would happen if the craft was unable to return (whether by miscalculation, mechanical fault, rocket failure, software bug, virus or other unanticipated mishap)?

RESPONSE:Jonathan Amos-Online wrote:John. If you are referring to Skylon, it breathes air only to about
30km and then uses oxygen from a tank. It is rather like merging the
Pegasus-rocket-and-aircraft system into one unit, only much more
efficiently and with a greater uplift capacity. J

http://www.bbc.co.uk/

Thanks for the clarification. That was the missing piece I needed.
It would seem then that the capacity and range of the craft are tied to the capacity of the tank. Therefore a design limit exists for the range of the flight based on the size of the oxygen tank. This also explains why the flights are only to the edge of space (limited resources to extend the journey).

Do you know if the designers intend to modify the system for longer flights?