The Athena (Advanced Telescope for High ENergy Astrophysics) satellite, selected by ESA within its Cosmic Vision 2015-2025 programme, will be the next flagship X-ray astronomy satellite. Athena will study how hot baryons assemble into groups and clusters of galaxies and determine their chemical enrichment across cosmic time. It will study the physics of accretion into compact objects, find the earliest accreting supermassive black holes and trace their growth, showing how they influence the evolution of galaxies and clusters through feedback processes. Athena will have a fast target of opportunity (TOO) observational capability, enabling studies and usage of GRBs and other transient phenomena. As an observatory, it will offer information on high-energy phenomena on all classes of astrophysical objects, from solar system bodies to the most distant objects known. Athena will carry two instruments, the Wide Field Imager (WFI) providing sensitive wide field imaging and spectroscopy and high count-rate capability, and an X-ray Integral Field Unit (X-IFU) delivering spatially resolved high-resolution X-ray spectroscopy over a limited field of view. KIPAC members are helping to build these instruments and develop the Athena science program.