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

Russian officials have delayed until Saturday the launch of a Proton rocket from Kazakhstan with the Spektr-RG X-ray astronomy observatory, an ambitious mission jointly developed with Germany to probe dark energy.

Three new crew members embarked on a six-month expedition aboard the International Space Station Thursday with a launch from Kazakhstan on top of a Russian Soyuz rocket at 0805 GMT (4:05 a.m. EDT). NASA astronaut Chris Cassidy and crewmates Anatoly Ivanishin and Ivan Vagner docked with the space station at 1413 GMT (10:13 a.m. EDT) Thursday.

Riding on its side aboard a rail car, a Proton rocket trekked to its launch pad Tuesday at the Baikonur Cosmodrome in Kazakhstan with a Eutelsat television broadcast satellite ready for liftoff Friday.