Live coverage: Vega rocket launches with LISA Pathfinder

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.

Inverted cables on the Vega rocket’s upper stage control system apparently caused the launcher to tumble minutes after liftoff Monday night, a failure that resulted in the loss of a Spanish Earth observation satellite and a French research probe, Arianespace officials said Tuesday.

Astronauts Butch Wilmore and Terry Virts suited up and ventured outside the International Space Station on Sunday on their third spacewalk in eight days to install equipment to help future commercial crew capsules built by Boeing and SpaceX navigate to the complex.