Live coverage: Soyuz crew lands in Kazakhstan

Watch a video replay of NASA’s Parker Solar Probe lifting off from Cape Canaveral Air Force Station’s Launch Complex 37 atop a United Launch Alliance Delta 4 Heavy on August 12, 2018.

Two Russian cosmonauts floated outside the International Space Station Thursday for a planned six-hour spacewalk to manually launch five small satellites, to test a variety of spacesuit upgrades, to retrieve an external experiment and to carry out routine inspections and maintenance.

Three years and a billion miles past Pluto, NASA’s New Horizons probe is on the verge of at least one more pioneering, once-in-a-lifetime milestone: a New Year’s Day flyby of a small body known as 2014 MU69, unofficially dubbed Ultima Thule — “beyond the known world” — in a NASA naming contest.