Live coverage: Rosetta’s final hours

Loaded with three commercial satellites, a European Ariane 5 rocket returned to its launch pad in French Guiana Thursday after a two-week launch delay to resolve a technical issue that forced an abort to a countdown July 31. Arianespace says the mission has been rescheduled for launch Saturday due to unfavorable upper level winds in the forecast for Friday.

Four decades after NASA’s Viking landers acquired humanity’s first view of the surface of Mars, a planet whose reality lived in the imaginations of skywatchers for millennia, a definitive smoking gun for microbial life there still eludes scientists.

A Soyuz rocket launched from the Baikonur Cosmodrome in Kazakhstan at 1:55 a.m. EST (0655 GMT) Sunday with the Arktika-M 1 spacecraft, the first in a new line of Russian satellites designed to provide weather observations over the Arctic.