The U.S. military’s next GPS navigation satellite was ready for launch from Cape Canaveral at 9:43 p.m. EDT Friday (0143 GMT Saturday) aboard a SpaceX Falcon 9 rocket. But SpaceX aborted the countdown just two seconds prior to liftoff.

NASA and Boeing managers have again decided to extend the Starliner crew capsule’s stay at the International Space Station, passing up a June 26 re-entry to allow more time for analysis and testing to make sure helium leaks and thruster failures are fully understood, officials said late Friday.

The Falcon 9 booster that launched four astronauts toward orbit last weekend arrived back on Florida’s Space Coast Thursday aboard a SpaceX drone ship, sailing into Port Canaveral with a lean but otherwise in seemingly good shape after it apparently slid across the ship’s deck in high winds and rough seas. Assuming post-flight inspections reveal no major issues, SpaceX aims to reuse the booster to launch the next Crew Dragon mission in 2021.