Watch the Falcon 9 and Crew Dragon arrive at the launch pad (members only)

Ground controllers transmitted commands to shut down the second of NASA’s Van Allen Probes on Friday, three months after turning off an identical satellite to conclude a seven-year mission that explored the donut-shaped radiation belts surrounding Earth.

Boeing engineers are close to resolving concerns with the mass and aerodynamic shape of the company’s CST-100 Starliner commercial crew carrier, and officials are optimistic the spaceship will be ready to deliver astronauts to the International Space Station in early 2018.

SpaceX called off a Falcon 9 countdown Wednesday due to the threat of lightning from thunderstorms along Florida’s Space Coast, pushing back the departure of a cargo mission for the International Space Station until Thursday.