Q&A with Rolf de Groot, head of ESA’s robotic exploration office

Two weeks after a sensor problem forced a delay, an Ariane 5 rocket blasted off at 6:04 p.m. EDT (2204 GMT) Saturday from French Guiana with two commercial communications satellites to cover the United States and Japan, and a Northrop Grumman-built robotic satellite servicing mission designed to link up with another spacecraft in geostationary orbit.

A U.S.-built commercial communications craft owned by Intelsat and a new node for Europe’s laser data relay satellite network rocketed into orbit Tuesday from Kourou, French Guiana, on top of an Ariane 5 rocket.

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.