Uh-oh, the International Space Station is leaking again

Key points

• NASA confirmed Thursday that the Russian segment of the International Space Station has begun leaking atmosphere into space again.
• It’s an old problem that NASA recently hoped was resolved.
• For more than half a decade, engineers from Roscosmos and NASA have been tracking the leak rate from a small Russian module attached to the space station that leads to a docking port.
• The source of these leaks, microscopic structural cracks, have been difficult to find and address.
• In January, NASA said that after multiple inspections and sealant applications, the pressure inside this segment, known as the PrK module, had reached a “stable configuration.” The PrK module is essentially a transfer tunnel attached to the Zvezda Service Module on the Russian segment of the space station.