The capsule, also called Dragon or Dragon 2, approached the space station very gradually, carefully synchronizing its speed and trajectory.
The Demo-1 mission marks the first flight of the new and improved Dragon 2 spacecraft, which is longer and more massive than its Dragon 1 predecessor.
SpaceX's Crew Dragon is successfully docked with the International Space Station! This latest, flashiest Dragon is on a fast track to reach the space station Sunday morning, just 27 hours after liftoff.
"This is a good day - first day of a new era for the next generation of space explorer", Saint-Jacques said during a live broadcast of the welcoming ceremony. Around 0900 GMT, Dragon was 3,000 meters away, Nasa said. The capsule will remain at the ISS for another five days.
"Roscosmos congratulates NASA on the successful docking of the new ship and emphasizes that flight safety must be immaculate", the space agency tweeted according to Google Translate.
"We're on the precipice of launching American astronauts on American rockets from American soil again for the first time since the retirement of the space shuttles in 2011", said Bridenstine, who got a special tour of the launch pad on the eve of launch, by Musk. It's a first for a commercially built & operated spacecraft designed for crew! The next one coming up will have its own two-man crew. TV cameras on Dragon as well as the station provided stunning views of one another throughout the rendezvous.
With permission to enter the Keep Out Sphere (KOS), Dragon approached to within 150 meters of the docking port, where the station's crew will test a retreat command. The astronauts wore oxygen masks and hoods until getting the all-clear. If that final phase of the test goes well, NASA astronauts could be heading into space aboard non-NASA rockets as soon as summer 2019. Both astronauts were at SpaceX Mission Control in California, observing all the action. Tourists flocked to the Kennedy Space Centre in Florida to watch the launch of the Falcon 9 rocket at 2.49am local time on Saturday.
"Congratulations to all of the teams on a successful docking", NASA astronaut Anne McClain radioed from the station.
Jim Bridenstine, head of the U.S. space agency, has explained NASA wants to reduce costs in low orbit to devote resources to getting back to the Moon and constructing a small space station in lunar orbit in the 2020s. It docked autonomously under the station astronauts' watchful eyes, instead of relying on the station's robot arm for berthing.
After soft capture, Dragon's docking hardware automatically sealed itself with the station, completing a hard docking.
NASA TV coverage of rendezvous and docking began at 03:30 EST (08:30 UTC), in the middle of the night here in the USA, with Dragon roughly 2.5 kilometers behind and 7.5 kilometers above the ISS. They burst into applause again, several minutes later, when the Dragon's latches were tightly secured.
There they found the dummy, Ripley, strapped to a seat, and an untethered plush toy in the form of the blue planet, which SpaceX had jokingly placed there as a "super high-tech zero-g indicator".
The Crew Dragon is set to detach from the ISS on Friday morning before returning to Earth.
Ripley and the capsule are rigged with sensors to measure noise, vibration and stresses and monitor the life-support, propulsion and other critical systems.
SpaceX aims to launch Behnken and Hurley as early as July.