Following its successful liftoff and entry into orbit on Saturday, SpaceX's Crew Dragon spacecraft has ticked off another critical milestone in its first mission to space, dubbed Demo-1. The unmanned capsule has now successfully docked with the ISS following a first-of-a-kind maneuver, clearing the way for astronauts aboard the orbiting laboratory to open up the hatch and have a poke around.

SpaceX has been delivering and collecting cargo from the ISS using its Dragon spacecraft for years, but Saturday's launch was the first time a version decked out for human travel was fired into obit. Lifting off aboard SpaceX's Falcon 9 rocket on Saturday morning, the spacecraft carried out a series of orbital maneuvers to set itself on course for a rendezvous with the Space Station the following day.

When SpaceX's Dragon spacecraft travels to the ISS with cargo, it is captured by the crew using the station's robotic arm and pulled into place. But the Crew Dragon spacecraft's docking procedure is a little different, instead relying on automated control software to attach itself to the desired module on the outside of the station.

For that reason, with live crew inside, mission control treaded carefully, arriving at a distance of around 150 meters (492 ft) away, before backing off to around 180 m (590 ft) and only then delivering the final command to dock as crew watched on inside.

Using the station's new international docking adapter, which was installed during a 2015 spacewalk, the Crew Dragon then successfully attached itself to the Harmony module at around 6am on Sunday morning, marking the first autonomous docking of any US spacecraft to the ISS.

After some leak and pressurization checks, NASA astronaut Anne McClain, Canada's David Saint-Jacques of the Canadian Space Agency and Russian cosmonaut Oleg Kononenko opened up the hatch and ventured inside. Though the craft didn't carry any humans this time around, a test dummy called Ripley did go along for the ride to gather biometric data using built-in sensors. Also packed inside were around 400 lb (181 kg) of supplies and equipment.

The capsule will remain in place for a total of five days before gearing up for its next challenge, a return to Earth. This equally vital testing phase will see Crew Dragon zip through the Earth's atmosphere before deploying a set of four parachutes designed to bring it down gently onto the surface of the Atlantic Ocean. Using a brand new purpose-built recovery vessel, SpaceX is then required to get the spacecraft out of the water within one hour of splashdown.

Source: NASA

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