After replacing a faulty inertial measurement system blamed for a scrubbed launch attempt Sunday, a Soyuz rocket headed to space from French Guiana today with five satellites, including the next spacecraft for Europe’s multibillion-dollar Earth observing network and a French experiment to probe the validity of Einstein’s theory of general relativity.

Scientists eager for answers to long-standing questions about the geology of Mars will get a lift Saturday with the blastoff from California of an Atlas 5 rocket with NASA’s InSight mission, a robotic landing craft that will take the pulse and temperature of the red planet.

SES announced Thursday it has tapped SpaceX for two additional Falcon 9 rocket launches from Cape Canaveral to deliver more Boeing-built O3b mPower broadband satellites into orbit, adding to a pair of Falcon 9 flights ordered by SES last year to launch the first batch of mPower platforms beginning in late 2021.