Video: Alice Bowman, New Horizons mission operations manager, previews Ultima Thule flyby (members only)

SpaceX’s first Crew Dragon spacecraft, fixed to the forward end of a Falcon 9 rocket, emerged Thursday from the company’s hangar at the Kennedy Space Center in Florida for the quarter-mile journey to its launch mount at pad 39A, where liftoff is scheduled early Saturday on a critical test flight before astronauts strap into the ship later this year.

The proposals are in for a new NASA mission for launch in 2021 to explore the solar system, and scientists have submitted concepts for probes to the moon, planets, asteroids and comets for a chance to win $450 million in federal funding.

A commercial Cygnus cargo freighter packed with 3.8 tons of medical and pharmaceutical experiments, technology demonstration hardware, CubeSats and crew provisions rode an Antares rocket into orbit from Virginia’s Eastern Shore on Wednesday afternoon on the first leg of a day-and-a-half journey to the International Space Station.