Live coverage: Vega rocket launches with LISA Pathfinder

A pair of innovative satellites for ViaSat and Eutelsat, valued at approximately $800 million, are scheduled to lift off Thursday on an Ariane 5 rocket from French Guiana, hauling the heaviest and costliest commercial payload ever launched.

The Emirates Mars Mission, the first deep space probe from the Arab world, steered into orbit around the Red Planet on Tuesday to cap a 307 million-mile (494 million-kilometer), 205-day interplanetary voyage from Earth and begin a science mission studying the Martian climate. The critical 27-minute Mars Orbit Insertion maneuver began at 10:30 a.m. EST (1530 GMT).

Two NASA astronauts and an Italian flight engineer took shelter in the space station’s Russian segment Wednesday as mission control analyzed a possible leak of toxic ammonia coolant aboard the complex. Initial data indicated it was likely a false alarm.