ESA scales back design for its X-ray astronomy mission

WASHINGTON — Faced with rising costs, the European Space Agency is looking for ways to overhaul the design of a large X-ray space telescope, an effort that could have implications for NASA’s own astrophysics programs.

ESA selected the Athena mission in 2014 as one of two flagship astrophysics missions, along with the Laser Interferometer Space Antenna (LISA). Athena – a name derived from Advanced Telescope for High-Energy Astrophysics – would be launched in the mid-2030s to study supermassive black holes, supernova explosions and other X-ray sources using a large mirror at X-rays.

At the time of selection, each mission has an estimated cost to ESA of 1.05 billion euros ($1.07 billion), or about 1.17 billion euros today, said Paul McNamara , ESA’s Astronomy and Astrophysics Coordinator, during a July 21 presentation at NASA Astronomy and Astrophysics. Committee. By 2019, however, the combined price of Athena and LISA had risen to €2.5 billion.

In May 2022, LISA had an estimated cost of €1.5 billion, but Athena had grown to €1.9 billion. This happened even as Athena was making good technical progress, he said, such as in the development of new light mirror technology.

Much of the recent increase, he said, came after member states that had planned to make their own contributions to the mission pulled out. “Several member states concluded that they were unable to fulfill their commitments,” he said, “and they asked ESA to take responsibility.” This increased the cost to the ESA for Athena.

“These costs are not sustainable,” he said. “If we want to maintain the diversity of content that is at the heart of our program, we must reduce the cost of our major missions.”

McNamara said the ESA was not considering canceling Athena, but rather the agency was considering some sort of “reframed” mission with a cost no more than 1.3 billion euros. “We need to reframe Mission Athena to significantly reduce its cost.”

This cropped mission, currently dubbed NewAthena, would likely involve cutting back on its science. “At the moment it doesn’t seem possible that we can reach 1.3 [billion euro] objective, the cost of completion for ESA, while maintaining the full scientific objectives of the mission,” he said.

This effort will involve potential modifications to the configuration of its instruments as well as the creation of a scientific “redesign” team to reconsider the scientific objectives. The aim will be to develop a revised concept, called a minimally disturbed mission, which will cost ESA no more than 1.3 billion euros, but which will still perform the science expected of a flagship-class mission.

What this means for Athena’s calendar is unclear. McNamara said ESA is preparing to “adopt” or move to the next phase of development, either Athena or LISA in November 2023. The other will be adopted in 2024 or 2025.

Another uncertainty is the funding that will be available in the next few years for Athena and LISA, which ESA Member States will decide at the next Ministerial Council in November. “At this time, we are assuming a potential level of resources for the future,” he said. “If we don’t get that, we don’t know what’s going to happen.”

A redesign of Athena could also affect NASA. The agency is providing hardware for an instrument on Athena as well as other resources, such as test and calibration facilities for its X-ray mirror. McNamara said ESA officials have been in contact with their NASA counterparts about plans for Athena.

He added that ESA would not rule out increased cooperation with NASA as a way to reduce ESA’s costs for the revised Athena mission. “No door is closed,” he said. “We are looking at every way to try to get the best mission possible within the programmatic constraints.”

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