Russian launch crews on two continents are putting the final touches on a pair of Soyuz rockets scheduled to blast off less than two hours apart Friday — one carrying a three-man crew to the space station, and another boosting two European navigation satellites into orbit from the Amazon jungle.

A European-built Ariane 5 rocket launched Tuesday with a U.S.-made communications satellite for Tokyo-based Sky Perfect JSAT and a South Korean environmental observatory. The heavy-lift Ariane 5 launcher took off from the Guiana Space Center in Kourou, French Guiana, at 5:18 p.m. EST (2218 GMT; 7:18 p.m. French Guiana time).

Leaving six crewmates behind in orbit, a Russian commander, his NASA co-pilot and a first-time flier from the United Arab Emirates undocked from the International Space Station early Thursday, executed a fiery plunge back to Earth and landed safely on the steppe of Kazakhstan.