Live coverage: Ariane 5 blasts off with two Intelsat satellites

The European Space Agency’s LISA Pathfinder spacecraft, destined to test the concept of gravitational wave detection a million miles from Earth, is nearly ready for launch Dec. 2.

A Falcon 9 rocket lifted off from Vandenberg Air Force Base at 4:39 a.m. PDT (7:39 a.m. EDT; 1139 GMT) Wednesday, and SpaceX successfully landed the rocket’s first stage on a drone ship in the Pacific Ocean. The mission’s primary objective is the deployment of 10 Iridium Next communications satellites into low Earth orbit.

An Ariane 5 countdown in French Guiana was aborted Tuesday with the European-made rocket’s main engine already running, postponing the launch of two commercial communications satellites until engineers can resolve the problem.