Watch a video replay of NASA’s exoplanet announcement

During a fourth spacewalk Saturday to wrap up repairs of the coolant system in a $2 billion cosmic ray detector, Italian astronaut Luca Parmitano and Drew Morgan discovered a leak in one of eight coolant lines that were spliced into a new pump module during three earlier excursions. But Parmitano was able to tighten a fitting on the line and the astronauts were able to complete the repair work, setting the stage for the instrument to resume science operations.

SpaceX’s next launch of satellites for the company’s Starlink broadband network — planned in the final days of 2019 — will carry one spacecraft with an experimental coating designed to make it less reflective in orbit, a first step in assuaging concerns from scientists who say the deployment of thousands more Starlink stations would impede some astronomical observations.

One-half of the instrument payload aboard NASA’s $916 million Soil Moisture Active Passive satellite has failed after collecting just two months of data, NASA announced Wednesday after weeks of troubleshooting turned up no progress in recovering the sensor.