Astronaut Scott Kelly and cosmonaut Mikhail Kornienko ended a record-setting 340-day stay in orbit with a fiery plunge to Earth Tuesday, settling to a jarring rocket-assisted touchdown in Kazakhstan to close out a medical research voyage that may help pave the way for flights to Mars.

SpaceX is gearing up for launch of an unpiloted Crew Dragon spacecraft from the Kennedy Space Center for a crucial test of the crew capsule’s launch abort system. A modified Falcon 9 rocket performed a test-firing at launch pad 39A Saturday before carrying the Crew Dragon spacecraft into the upper atmosphere for an in-flight abort test scheduled for Jan. 18.

A Russian Soyuz spacecraft featuring a variety of avionics upgrades and other changes to improve reliability and performance docked with the International Space Station early Saturday after a two-day orbital chase, bringing three fresh crew members to the lab complex.