that there was potential value for the platform if organised as a multinational European venture, similar to the conventional Europa and Ariane launchers. In early 1967, the last major design study on the topic was drawn up, after which the project was continued at a lower level until work on Mustard was finally terminated in 1970 by the British government, who had decided to participate in the new American post-Apollo project instead. Accordingly, a number of key Mustard project staff had spent the first two years of the 1970s overseas at North American Rockwell, where they contributed to the initial study which would eventually lead to the US Space Shuttle. Around this time, the prospect of collaboration is said to have faded and, in the absence of significant interest from the British government, the Mustard project was effectively terminated. In early 1977, BAC was itself later merged with rival Hawker Siddeley to form British Aerospace (B.Ae) and when the reusable HOTOL spaceplane project arose in 1984, the project team was relocated to Warton, where they took advantage of the expertise that had been accumulated during the earlier Mustard project. Writing of Mustard's cancellation, Henbest wrote that the absence of "political courage" had been largely responsible for the failure of the venture to become reality; furthermore, if further research had been financed by the Ministry of Aviation, then Britain may have been able to play a larger role in other space programmes, such as the American Space Shuttle. Design Modules Mustard was a modular reusable space launch system, comprising multiple copies of a single vehicle design, each of which was configured for a different role as a booster stage or an orbital spaceplane. The core vehicle design resembled the basic layout of the Douglas Astro, both being delta-winged reusable vehicles, as would the later American Space Shuttle. Furthermore, all three functioned as vertically launched rockets and used integral wings so that they could land horizontally, akin to an aeroplane. The design evolved through a total of fifteen proposed variants or schemes, each typically comprising a deep-keeled lifting-body airframe with delta wings in a smooth blended wing body layout, with twin tail fins rising from the wing tips and canted outwards. Some early variants featured a compound-delta wing, complete with inboard tail fins. Power was provided by an arrangement of between one and four rocket engines positioned upon the rear fuselage. Due