Your correspondent Tony Beswick suggests that my company's Ascender spaceplane could be launched by Concorde to make it capable of reaching orbit (Flight International, 18-24 November). Ascender itself would be sub-orbital, like the 1960s X-15. Our Spacecab project looks not all that different, but we decided that it would be less expensive to develop an all-new carrier aeroplane. Concorde does, however, provide a most useful technical database.

The feasibility study that we carried out for the European Space Agency shows that the optimum maximum speed for the carrier aeroplane is about Mach 4. One could add rockets to Concorde so that it would reach this speed, but it would be aerodynamically unstable.

If the lessons from Concorde can be well learned, Europe can take the lead in developing a spaceplane that will revolutionise spaceflight.

D M Ashford Bristol Spaceplanes, Bristol, UK

Source: Flight International