Poised to loft a Russian-German X-ray astronomy observatory into space Friday, a Proton rocket returned to its launch pad Tuesday at the Baikonur Cosmodrome in Kazakhstan after a three-week delay to replace a drained battery on the vehicle.

Amazon founder Jeff Bezos, the world’s richest person, discussed his vision for spaceflight and lunar exploration Thursday in Washington, revealing new details about a privately-developed lunar lander he said will help NASA achieve the Trump administration’s goal of returning astronauts to the surface of the moon by 2024.

Sierra Nevada Corp. has booked at least six launches on United Launch Alliance’s new Vulcan Centaur rocket to carry Dream Chaser supply ships into orbit on cargo runs to the International Space Station beginning in 2021, becoming the first confirmed customer for ULA’s next-generation launcher.