Live coverage: Two telecom satellites launched by Falcon 9, booster recovery fails

Liftoff of an Ariane 5 rocket from a tropical launch pad in South America was halted moments after its main engine ignited Tuesday in a rare last-second abort for the heavy-lift launcher.

SpaceX has postponed the launch of its next Falcon 9 rocket indefinitely. The rocket was originally scheduled take off Wednesday from pad 39A at NASA’s Kennedy Space Center in Florida with a top secret U.S. government payload named Zuma. A few minutes after launch, the Falcon 9’s first stage will return for a landing at nearby Cape Canaveral Air Force Station.

Four veteran astronauts have been selected to train for launch aboard new commercial crew capsules being built by Boeing and SpaceX that are intended to ferry astronauts to and from the International Space Station starting in 2017, NASA announced Thursday.