Photos: Atlas 5 rocket aims for International Space Station

An Ariane 5 countdown in French Guiana was aborted Tuesday with the European-made rocket’s main engine already running, postponing the launch of two commercial communications satellites until engineers can resolve the problem.

Four astronauts flying on SpaceX’s Crew Dragon “Resilience” spacecraft reached the International Space Station late Monday, one day after launching from the Kennedy Space Center in Florida. The capsule autonomously docked with the space station at 11:01 p.m. EST Monday (0401 GMT Tuesday).

An unexpected, quickly-planned spacewalk is on tap Monday to troubleshoot a problem preventing the International Space Station’s robot arm transporter from reaching a worksite where it can be locked down, a requirement before a Russian Progress cargo ship can dock later in the week.