Optimizing payloads for ESAs future science missions

The long-term science program of the European Space Agency - Cosmic Vision 2015-2025 - is further being shaped for mission launches beyond 2015. This program aims at answering the fundamental questions ranging from how the Solar System works, what the conditions for planet formation and for emergence of life are, to how the Universe was formed and what it is made of. The first two missions for launches in 2017 and 2019 have been selected: Solar Orbiter, a mission aimed at observing the Sun, and Euclid, a dark energy mission. In addition, SPICA, a JAXA-led mission - a next generation infrared observatory - is retained as a mission of opportunity with ESA contributions. For launch in the early 2020s, four candidates for medium class missions have been selected for assessment: the Exoplanet Characterization Observatory (EChO), the Large Observatory for X-Ray Timing (LOFT), a sample return mission of material from a primitive near Earth asteroid (Marco Polo-R) and the Space-Time Explorer and Quantum Equivalence Principle Space Test (STE-QUEST). In addition, there are three large-class mission concepts under formulation also for launch in the early 2020s: A next generation X-ray observatory, a gravitational wave observatory and a mission to Jupiter's moons. This paper presents the progress in payload definition and optimization for the mission candidates and will highlight the future steps to build a comprehensive science program.