Snapshots from Atlas 5 launch

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.

Tugged along a historic route leading to the launch pad where Yuri Gagarin took off 1961 to become the first person in space, a Soyuz rocket rolled out of its assembly hangar in Kazakhstan and stood up on its launch mount Sunday.

A United Launch Alliance Delta 2 rocket fired away from a California military base and disappeared into an overcast cloud deck Saturday on its final flight, carrying a NASA research satellite into orbit and closing the book on a nearly 30-year legacy of launches.