Solid propulsion for space applications: An updated roadmap

For the last 50 years solid propulsion has successfully created a multitude of small launchers and many first stages or boosters for heavy launchers with low risk, high performance, competitive cost, superb storability, and “instant” readiness in many countries. Technical support for these successes arose from simple designs, very high thrust levels, and low development and operation costs/risks. The first solid propulsion roadmap based on these foundations and rational projections was published in 2000 [A. Davenas, D. Boury, M. Calabro, B. D’Andrea, A. McDonald, Solid propulsion for space applications: a roadmap, in: 51st International Astronautical Congress, paper IAA-00-IAA.3.3.02, October 2000]. Moreover, subsequent information supports its enabling technologies (high strength composite cases, energetic material processing based on continuous mixing, low density insulation, reduced actuator energy requirements, and advanced detailed simulations) and applications (first stages, strap-on, add-ons, small launchers, and niche space applications). Missions currently devoted to solid propulsion and plans for present and future launchers and exploration mission developments in the USA, Japan, and Europe are sketched and targeted improvements, and potential breakthroughs are discussed.