NASA's final test telescope brings a 2.5-million-km ear for black holes one step closer

At NASA's Goddard Space Flight Center, engineers have commissioned the last rehearsal for one of the most delicate instruments ever built: an all-glass telescope carved from a ceramic that barely changes shape in heat or cold. Three of them will fly in a triangle 2.5 million km wide, bouncing lasers between gold-coated mirrors to feel gravitational waves — tiny squeezes in space-time from black holes merging billions of light-years away. Program lead Ritva Keski-Kuha calls it the team's first optical telescope delivery to the European Space Agency. Launch is slated for the mid-2030s.