Live coverage: Soyuz blasts off on third mission for O3b

An Ariane 5 rocket emerged from the final assembly building at the Guiana Space Center in South America on Monday for the journey across the tropical spaceport to the ELA-3 launch zone, where the 179-foot-tall (54.8-meter) booster will lift off Tuesday with a pair of commercial communications satellites.

International Space Station managers have named crew members to future expeditions to the research lab in 2017 and 2018, including the first German commander of a space mission and Canada’s third astronaut to fly a long-duration residency on the complex.

European engineers are eager to test an experimental re-entry demonstrator Wednesday to validate technologies for future robotic exploration probes, winged space planes, and reusable rocket boosters.