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The finite element method (FEM) is opposed to direct testing as approach for the first-stage design of inflatable bodies, to investigate the applicability the method may have in this field. Two FEM tools, LS-DYNA [1] and ABAQUS [2] , are used for the modelling of the Yong Engineers’ Satellite 2 (YES2) and the Inflatable Re-entry Technology (IRT) concepts. The results thus obtained are compared to those reached through a testing campaign. As the inflatable is a new technology for re-entry and as the flexibility of the vehicles interacts with their aerodynamic performance, a new iterative FEM/fluid dynamics (FD) procedure is required. This paper presents this methodology, which is currently being developed and will be object of future work.This tool is studied with a membrane simulator. Finally, as further applications of an FEM tool, LS-DYNA is used to carry out a similarity analysis and to simulate the behaviour of a new method to reduce the effects of a leakage from an inflatable re-entry vehicle: the BREOGAN system, which combines effectiveness, simplicity and low cost.

The 2nd Young Engineers' Satellite (YES2) is a project to design and build an inherently-safe reentry capsule and enable it to land, for the first time, within inhabited zones of Europe [1], [4]. YES2 is launched on a Russian carrier spacecraft and from there will use a 30 km tether to achieve the required orbital deceleration to initiate reentry. YES2 is a programme of the Outreach Office of the European Space Agency, led by Delta-Utec in the Netherlands and executed by ~25 European universities. Cranfield has been leading the phase A, design of the re-entry capsule. The requirements for the capsule for such a landing are: • To weigh 20 kg minimum for a successful deployment. (AIR = 8kg\MASS = 12 kg) • To be inherently safe. • To bring safely a payload (mass >100 g) from space to earth. • To be able to recover the protected payload. 1 Inherently safe means that design choices make the nominal vehicle safe even in cases of a contingency. If analysis of the design proves difficult, we have to learn about the performance and iterate the design through actual testing. 54th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law 29 September 3 October 2003, Bremen, Germany IAC-03-U.1.07 Copyright © 2003 by the International Astronautical Federation. All rights reserved. We have decided to use a 2 meter diameter inflatable sphere-cone structure with an inflatable nose covered with insulating materials such as Nextel and Zylon. The structure is reinforced by three tori filled with gas (Helium, for instance). The capsule also contains instrumentation (camera, accelerometers, GPS system...) that is released before the re-entry. After re-entry only the inflatable parts of the capsule, the payload and the location system remain. To ensure a high degree of safety, the capsule will be designed to burn up in the atmosphere if any stage in the inflation fails. Although further work may be carried out to optimize the project, all mission requirements have been successfully accomplished. The next phase will be detailed design and manufacture, leading to launch as part of the Russian rocket Foton-M-3 payload in 2006.