Orion orbital trace

On its third flight Monday night, SpaceX’s Falcon Heavy rocket will fly to three different orbits with two dozen spacecraft on a mission set to last more than six hours, prompting SpaceX founder Elon Musk to declare it the company’s “most difficult launch ever.”

The launch of a Northrop Grumman Antares rocket with an automated commercial space station cargo vessel from Virginia was aborted less than three minutes before takeoff Sunday after engineers detected unusual readings from a ground support sensor. Northrop Grumman and NASA officials said the next launch attempt is scheduled for no earlier than Thursday.

A robotic arm extended from NASA’s OSIRIS-REx spacecraft briefly contacted the rugged surface of asteroid Bennu Tuesday to gobble up pristine samples, a climactic moment in the $1 billion mission to bring asteroid material back to Earth in 2023.