![](\"http:\/\/www.esa.int\/var\/esa\/storage\/images\/esa_multimedia\/images\/2019\/02\/athena_mirror_module\/19230429-1-eng-GB\/Athena_mirror_module_small.jpg\")
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\nThis \u2018mirror module\u2019 \u2013 formed of 140 industrial silicon mirror plates, stacked together by a sophisticated robotic system \u2013 is destined to form part of the optical system of ESA\u2019s Athena X-ray observatory.\n<\/p>\n
\nDue to launch in 2031, Athena<\/a> will probe 10 to 100 times deeper into the cosmos than previous X-ray missions, to observe the very hottest, high-energy celestial objects. To achieve this the mission requires entirely new X-ray optics technology.\n<\/p>\n \nEnergetic X-rays don\u2019t behave like typical light waves: they don\u2019t reflect in a standard mirror. Instead they can only be reflected at shallow angles, like stones skimming along water<\/a>. So multiple mirrors must be stacked together to focus them: ESA\u2019s 1999-launched XMM-Newton<\/a> has three sets of 58 gold-plated nickel mirrors, each nestled inside one another. But to see further, Athena needs tens of thousands of densely-packed mirror plates.\n<\/p>\n \nA new technology had to be invented: \u2018silicon pore optics\u2019, based on stacking together mirror plates made from industrial silicon wafers, which are normally used to manufacture silicon chips.\n<\/p>\n \nIt was developed at ESA\u2019s ESTEC technical centre in the Netherlands, and patented by ESA, invented by an ESA staff member with the founder of cosine Research<\/a>, the Dutch company leading an European consortium developing Athena\u2019s optics.\n<\/p>\n \nThe technology was refined through a series of ESA R&D projects, and all process steps have been demonstrated to be suitable for industrial production. The wafers have grooves cut into them, leaving stiffening ribs to form the \u2018pores\u2019 the X-rays will pass through. They are given a slight curvature, tapering towards a desired point so the complete flight mirror can focus X-ray images.\n<\/p>\n \n\u201cWe\u2019ve produced hundreds of stacks using a trio of automated stacking robot,\u201d explains ESA optics engineer Eric Wille. \u201cStacking the mirror plates is a crucial step, taking place in a cleanroom environment to avoid any dust contamination, targeting thousandth of a millimetre scale precision. Our angular resolution is continuously improving.\u201d\n<\/p>\n \n\u201cOngoing shock and other environmental testing ensures the modules will meet Athena\u2019s requirements, and the modules are regularly tested using different X-ray facilities.\u201d\n<\/p>\n \nAthena\u2019s flight mirror \u2013 comprising hundreds of these mirror modules \u2013 is due for completion three to four years before launch, to allow for its testing and integration.\n<\/p>\n \nEach new ESA Science mission observes the Universe in a different way from the one before it, requiring a steady stream of new technologies years in advance of launch. That\u2019s where ESA\u2019s research and development activities come in, to early anticipate such needs, to make sure the right technology is available at the right time for missions to come.\n<\/p>\n \nLong-term planning is crucial to realise the missions that investigate fundamental science questions, and to ensure the continued development of innovative technology, inspiring new generations of European scientists and engineers.\n<\/p>\n \nScience is everywhere at ESA. As well as exploring the Universe and answering the big questions about our place in space we develop the satellites, rockets and technologies to get there. Science also helps us to care for our home planet. All this week we’re highlighting different aspects of science at ESA. Join the conversation with #ScienceAtESA.<\/i><\/p>\n","protected":false},"excerpt":{"rendered":" \nThis ‘mirror module’ – formed of 140 industrial silicon mirror plates, stacked together by a sophisticated robotic system – is destined to form part of the optical system of ESA’s Athena X-ray observatory.\n<\/p>\n \nDue to launch in 2031, Athena<\/a> will probe 10 to 100 times deeper into the cosmos than previous X-ray missions, to observe the very hottest, high-energy celestial objects. To achieve this the mission requires entirely new X-ray optics technology.\n<\/p>\n \nEnergetic X-rays don’t behave like typical light waves: they don’t reflect in a standard mirror. Instead they can only be reflected at shallow angles, like stones skimming along water<\/a>. So multiple mirrors must be stacked together to focus them: ESA’s 1999-launched XMM-Newton<\/a> has three sets of 58 gold-plated nickel mirrors, each nestled inside one another. But to see further, Athena needs tens of thousands of densely-packed mirror plates.\n<\/p>\n \nA new technology had to be invented: ‘silicon pore optics’, based on stacking together mirror plates made from industrial silicon wafers, which are normally used to manufacture silicon chips.\n<\/p>\n<\/p>\n