SpaceX delivered two astronauts to the International Space Station for NASA today, following up a historic liftoff with an equally smooth docking in yet another first for Elon Musk's company.

With test pilots Doug Hurley and Bob Behnken poised to take over manual control if necessary, the SpaceX Dragon capsule pulled up to the station and docked automatically, no assistance needed.

It was the first time a privately built and owned spacecraft carried astronauts to the orbiting lab in its nearly 20 years. NASA considers this the opening volley in a business revolution encircling Earth and eventually stretching to the moon and Mars.

The docking occurred just 19 hours after a SpaceX Falcon 9 rocket blasted off Saturday afternoon from Kennedy Space Center, the nation's first astronaut launch to orbit from home soil in nearly a decade.

Thousands jammed surrounding beaches, bridges and towns to watch as SpaceX became the world's first private company to send astronauts into orbit, and ended a nine-year launch drought for NASA.

A few hours before docking, the Dragon riders reported that the capsule was performing beautifully. Just in case, they slipped back into their pressurized launch suits and helmets for the rendezvous.

The three space station residents kept cameras trained on the incoming capsule for the benefit of flight controllers at SpaceX headquarters in Hawthorne, California, and NASA's Johnson Space Center in Houston.

Gleaming white in the sunlight, the Dragon was easily visible from a few miles out, its nose cone open and exposing its docking hook as well as a blinking light. The capsule loomed ever larger on live NASA TV as it closed the gap.

Hurley and Behnken took over the controls and did a little piloting less than a couple hundred yards (meters) out as part of the test flight, before putting it back into automatic for the final approach. Hurley said the capsule handled "really well, very crisp."

SpaceX and NASA officials had held off on any celebrations until after Sunday morning's docking — and possibly not until the two astronauts are back on Earth sometime this summer.

NASA has yet to decide how long Hurley and Behnken will spend at the space station, somewhere between one and four months. While they're there, the Dragon test pilots will join the one U.S. and two Russian station residents in performing experiments and possibly spacewalks to install fresh station batteries.

In a show-and-tell earlier Sunday, the astronauts gave a quick tour of the Dragon's sparkling clean insides, quite spacious for a capsule. They said the liftoff was pretty bumpy and dynamic, nothing the simulators could have mimicked.

The blue sequined dinosaur accompanying them — their young sons' toy, named Tremor — was also in good shape, Behnken assured viewers. Tremor was going to join Earthy, a plush globe delivered to the space station on last year's test flight of a crew-less crew Dragon. Behnken said both toys would return to Earth with them at mission's end.

An old-style capsule splashdown is planned.

After liftoff, Musk told reporters that the capsule's return will be more dangerous in some ways than its launch. Even so, getting the two astronauts safely to orbit and then the space station had everyone breathing huge sighs of relief.

As always, Musk was looking ahead.

"This is hopefully the first step on a journey toward a civilization on Mars," he said Saturday evening.