A hard X-ray complement to Athena: The prospect of hard X-ray astronomy in the 2030s and the FORCE mission

The Astro2020 decadal survey has recommended an X-ray mission complement to Athena for an upcoming Probe mission. Here we present the Focusing on Relativistic universe and Cosmic Evolution (FORCE) mission, the product of a JAXA/NASA collaboration that is capable of fulfilling much of this Probe science at a much lower cost. FORCE fills in a crucial energy-band gap above 10 keV and can be launched and operated on a timescale comparable to that planned for Athena. FORCE addresses how black holes grow and how they affect galaxy evolution, how non-thermal energy is generated and how much non-thermal energy is contained in the Universe, and how stars evolve and explode. These science objectives trace strongly to the Astro2020 Cosmic Ecosystems and New Messengers and New Physics themes, and also address the Worlds and Suns in Context theme. The power of FORCE, which will operate over 1-79 keV, lies in its unique combination of 1) a lightweight broadband X-ray mirror with a large effective area and high angular resolution (< 15 arcsec) and 2) a broadband X-ray imager with low detector background for increased sensitivity. These two key elements are connected by a high mechanical stiffness extensible optical bench with alignment monitor systems to realize the mirror focal length with high pointing accuracy. This presentation will cover the science case and mission design, particularly as it relates to Astro2020 decadal priorities.