The Athena x-ray optics development and accommodation

The Athena mission, under study and preparation by ESA as its second Large-class science mission, requires the largest X-ray optics ever flown, building on a novel optics technology based on mono crystalline silicon. Referred to as Silicon Pore Optics technology (SPO), the optics is highly modular and benefits from technology spin-in from the semiconductor industry. The telescope aperture of about 2.5 meters is populated by around 700 mirror modules, accurately co-aligned to produce a common focus. The development of the SPO technology is a joint effort by European industrial and research entities, working together to address the challenges to demonstrate the imaging performance, robustness and efficient series production of the Athena optics. A technology development plan was established and is being regularly updated to reflect the latest developments, and is fully funded by the ESA technology development programmes. An industrial consortium was formed to ensure coherence of the individual technology development activities. The SPO technology uses precision machined mirror plates produced using the latest generation top quality 12 inch silicon wafers, which are assembled into rugged stacks. The surfaces of the mirror plates and the integral support structure is such, that no glue is required to join the individual mirror plates. Once accurately aligned with respect to each other, the surfaces of the mirror plates merge in a physical bonding process. The resultant SPO mirror modules are therefore very accurate and stable and can sustain the harsh conditions encountered during launch and are able to tolerate the space environment expected during operations. The accommodation of the Athena telescope is also innovative, relying on a hexapod mechanism to align the optics to the selected detector instruments located in the focal plane. System studies are complemented by dedicated technology development activities to demonstrate the capabilities before the adoption of the Athena mission

Status of the demonstration of the critical technologies of the ATHENA telescope

The ATHENA (Advanced Telescope for High ENergy Astrophysics) mission is the current 2nd 'Large' mission (L2) in the ESA Cosmic Vision programme currently. It is currently at Phase B1 but the mission concept will now enter a reformulation phase that will follow a design-to-cost approach. This paper describes the main technologies behind its reference X-ray telescope based on the modular Silicon Pore Optics (SPO) technology. The large X-ray mirror is the mission enabler being specifically developed for ATHENA, in a joint effort by industry, research institutions and ESA. All aspects of the optics are being addressed, from the mirror plates and their coatings to the mirror modules and their assembly into the ATHENA telescope, as well as the facilities required to build and test the flight optics, demonstrating performance, robustness, and programmatic compliance. An overview of the status of the design and demonstration of the telescope is given. The risks that have successfully been mitigated are made explicit and the remaining risks are identified.</p