Video: Change of command aboard International Space Station

Citing medical reasons, Russia’s space agency announced Wednesday that it is replacing two cosmonauts who were scheduled to fly on the next Soyuz mission to the International Space Station in April with backup crew members.

A forecast of low ceilings, thick clouds and rainy weather Thursday has led NASA and Northrop Grumman officials to push back the launch of an Antares rocket and a space station-bound supply ship from Virginia’s Eastern Shore to Friday morning.

NASA expects to select commercial contractors to resupply the International Space Station in September, three months later than the agency’s previous timetable under a competition for cargo deliveries beginning in 2018.