Video: Marc Buie, New Horizons Occultation Team Lead (members only)

SpaceX test-fired the Falcon 9 rocket early Saturday ahead of launch with the next four astronauts heading to the International Space Station. The static fire test before sunrise Saturday in Florida was a major step toward liftoff Thursday.

Flying on autopilot more than 200 million miles from Earth, NASA’s OSIRIS-REx spacecraft is on track for a daring touch and go landing on an asteroid Tuesday to grab a sample for return to scientists eager to scan the specimens for clues about the history of the solar system.

Europe’s Rosetta spacecraft closed out a historic 4.9-billion-mile journey Friday with a slow-speed crash into the nucleus of comet 67P/Churyumov-Gerasimenko, the tiny world it has studied for the last two years, capturing some of the mission’s best science data to help unravel the inner workings of the comet. Confirmation of the crash landing arrived on Earth at 1119 GMT (7:19 a.m. EDT).