Manned spacecraft cost typically ten times as much to develop as advanced technology prototype aeroplanes of similar weight. For example, the Hermes spaceplane, which is designed to be launched into orbit by the expendable Ariane 5, has an estimated development cost of $4 billion, which is about ten times greater than the cost of the Experimental Aircraft Programme (EAP) demonstrator of the European Fighter Aircraft ($350 million). The Hermes spaceplane and the EAP are of comparable size and weight and both use very advanced technology. The EAP is already more mature than Hermes would become because, although the EAP is only a prototype, it has made more flights than are planned for Hermes over its entire operational career.

This part of the paper attempts to identify the factors which explain this difference in cost and then to determine which of them would apply to fully reusable, piloted, aeroplane-like launchers, i.e. aerospace transporters.

Tests were made to investigate the effects of Mach number on the oscillatory lateral derivatives of a three-surface, high-incidence research model (HIRM 1). Effects of Reynolds number and frequency parameter were also investigated at low speed. A new flexible sting and hydraulic actuator system were designed for the tests in the 2.4 m x 2.4 m Pressurised Wind Tunnel.

Results showed that the effects of Reynolds number and frequency parameter were not very significant at low speeds but there were quite large effects of Mach number on some derivatives, notably yawing and rolling moments due to sideslip and rate of yaw.

Numerical methods have been developed for the prediction of aerodynamic characteristics of canard wing configurations by considering both attached and separated flow over the canard surface; the flow over the main wing surface is always assumed to be attached. Experimental tests have been conducted in a low speed wind tunnel to compare the theoretical results predicted by the numerical methods. The comparison shows good agreement up to approximately 16° incidence.

The general theory of the stability of equilibrium of discrete conservative systems is reviewed with an eye to implementation in finite element structural analysis. The approach features a natural parameter, such as the applied loading of a system, as the independent variable; all results are thus conveniently established without recourse to any of the artificial parameters advocated by some earlier authors. The criteria for identifying singular (critical) points, which include bifurcation points and limit points, and determining their stability are obtained in simple forms suitable for computation. Numerical results are given for an example problem characteristic of a loaded plate with multiple, stable and unstable, bifurcation points to demonstrate an application of the theory.