No abstract

The use of new technologies in the design of the next generation solid rocket motors allows expecting significant reductions in their cost as well as an increase in their performance. Cost reductions can be obtained through key technologies simplifying the manufacturing flow chart, and the use of advanced materials can allow lower inert mass, and fewer parts leading thus to higher performance and lower cost in the same time.Application of these new technologies to an example of a possible future motor will be described in this paper. The selected application is a first stage motor (425 metric tons class) for a two-stage launcher (7 metric tons GTO class) studied in the frame of the French ELV2020 initiative, held by the French space agency CNES. Studies have been conducted for 3 years on this subject and lead to a precise vision of this motor.The studies on this motor have focused on the identification of its performance parameters and their link to the use of current (mature, high TRL) or next generation (low TRL, to be matured) technologies. This work has led to design two different motors with different technology maturities and to compare them. The paper will present the key performance figures achievable through these next generation motors, as well as the key technologies to be matured in the next years.Downloaded by CORNELL UNIVERSITY on July 30, 2015 | http://arc.aiaa.org |

The Ariane 5, Soyuz and Vega launchers will provide during the coming decade a wide range of mission options and performances capabilities for access to space of European institutional satellites and commercial satellites. Nevertheless this panel suffers from an overall low level of synergies and long term sustainability of the Soyuz is questionable. To improve this situation and prepare a more homogeneous and globally less expensive generation of launchers, numerous studies have been performed during the last years to identify new launcher designs and related motors/engines more adapted to an evolving market. Solid Rocket Motor (SRM) overall behaviour principle is well suited to very large thrust level required for launcher take-off. Moreover the SRM propulsive performances are obtained with a high level of reliability and competitive costs when compared to other expendable systems. This paper presents an overview of large solid rocket motor possibilities for a new generation of European launchers. It summarizes studies performed since a decade by Herakles (Merging of Snecma Propulsion Solide and former SNPE MatériauxEnergétiques) with the support of CNES and ESA. Several motor preliminary designs are presented to constitute a launcher family devoted to GTO mission ranging from 3 to 8 tons of payload capability. All options are based on a common cryogenic propellant upper stage for the whole family using the under development Vinci engine. For the lower stages a stack of two SRMs is taken into account with several possibilities of very large solid first stage, compatible with existing large production facilities in French Guyana, and a medium size solid second stage, more or less derived from the Vega P80 motor. Some options are using solid strap-on motors for versatility purpose. For each projects, the general motor design, propulsive performances and technical challenges to achieve payload target are presented.