The XEUS X-ray Telescope

The X-ray telescope forms the core of the high energy astrophysics observatory XEUS, currently under study at ESA as a well positioned candidate for its Cosmic Visions 1525 Science Programme, which is presently under formulation [1,2]. The science requirements of XEUS are particularly demanding, combining a large effective area (10m(2) at 1 keV), moderate angular resolution (5" requirement, with a goal of 2"), and a low mass for the optics system. The preferred operational orbit for XEUS is a halo orbit around the Lagrangian Point 2 (L2). Background and costing considerations led to the requirement of a single focal plane location, which in combination with the required broad energy response function, in turn requires a focal length of 50m. The mission design is based on formation flying, with the Mirror Spacecraft (MSC) flying inertially, and the Detector Spacecraft (DSC) actively following the focal point. The ambitious XEUS telescope relies on the novel X-ray technology currently under development in Europe [3, 4]. The X-ray optics technology development activities and status as well as the telescope design in general are addressed.