Costing about €1 billion, the flagship project will launch in 2028. It will weigh in at 5 tonnes, be about 12 metres long and will provide 100 times greater sensitivity than existing X-ray missions.
The telescope will have two main X-ray eyes. The Wide Field Imager instrument will look at relatively large areas of sky, scanning for X-ray emissions from supermassive black holes in the early universe.
"To find those, you need to make very deep images of the X-ray sky over a very wide area, because those objects are quite rare," says Kirpal Nandra of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who is leading the project.
Athena's other eye, the X-ray Integral Field Unit, will provide close-up views of objects that are known about already. It will look at a much smaller section of sky and analyse the energy of X-ray photons coming from cosmic bodies, to understand the physical processes driving their formation. These include tsunamis of hot gas found in galaxy clusters and the enormous auroras on Jupiter.
Now that it has mission approval from ESA, the Athena team needs to work out the fine details of the telescope and develop new technology for use in space before construction begins in early 2019. "When we say that we're going to build a telescope of a certain size, somebody has to design that telescope and work out exactly how it's going to be done," says Nandra.
Syndicated content: Jacob Aron, New Scientist
Image: ESA - Athena X-ray observatory