Live coverage: 400th Proton rocket takes off with Russian satellite

A Russian X-ray astronomy satellite with major contributions from German and U.S. scientists and instrument developers arrived Thursday at the Baikonur Cosmodrome in Kazakhstan for a launch in June aboard a Proton rocket.

SpaceX test-fired a Falcon 9 rocket for the second time Saturday after replacing a valve following an earlier static fire test Wednesday. The move has postponed the Falcon 9 rocket’s launch with the Amos 17 commercial communications satellite to no earlier than Tuesday.

The U.S. Air Force’s fourth new-generation SBIRS missile warning satellite is headed for geosynchronous orbit after lifting off from Cape Canaveral at 7:48 p.m. EST Friday (0048 GMT Saturday), after a one-day delay caused by a troublesome fill-and-drain valve.