Jason DavisMar 03, 2019

Crew Dragon Successfully Docks to International Space Station

SpaceX's Crew Dragon is successfully docked with the International Space Station! Docking occurred at 05:51 EST (10:51 UTC), and the crew officially opened Dragon's interior hatch at 08:07 EST (13:07 UTC). Both events happened ahead of schedule, as Dragon's first shakedown cruise continues to go very smoothly.

NASA TV coverage of rendezvous and docking began at 03:30 EST (08:30 UTC), in the middle of the night here in the U.S., with Dragon roughly 2.5 kilometers behind and 7.5 kilometers above the ISS. At that point, it was visible as a point of light during orbital night; earlier, the crew had also commanded Dragon to turn on its flashing strobe light.

Crew Dragon next fired its thrusters to begin an approach initiation burn, which brought it inside the approach ellipsoid, a 4-by-2-kilometer egg-shaped zone surrounding the station. About 40 minutes later it passed Waypoint 0, an imaginary spot 400 meters directly below the station. From there, it received a go to swing up in front of the station and enter the keep out sphere, the 200-meter-wide safety zone around the ISS.

International Space Station approach zones
International Space Station approach zones Two zones dictate how vehicles approach the International Space Station: the approach ellipsoid, which is 4-by-2 kilometers wide, and a smaller keep out sphere, which is 200 meters wide.Image: SpaceX

As Crew Dragon got closer, there were stunning views from a heads-up display inside Dragon, which could be seen by both the ground and astronauts aboard the ISS. 

At about 5:00 EST (10:00 UTC), Crew Dragon reached Waypoint 1, a spot 150 meters away from the station's forward docking port on Node 2, also known as Harmony. At 140 meters, NASA astronaut Anne McClain commanded Dragon to back away from the station, as part of a test of the spacecraft's contingency abilities. Dragon obliged, firing its 4 foward Draco thrusters and backing up to about 180 meters. There, McClain commanded it to hold position.

After another go/no-go poll, the SpaceX team in Hawthorne, California sent Dragon on its final approach to Waypoint 2, 20 meters from the docking port. There, it stopped for a final go/no-go poll. The views of Dragon from the station were incredible: 

Crew Dragon 20 meters from ISS
Crew Dragon 20 meters from ISS Crew Dragon holds position 20 meters away from the International Space Station's forward docking port on 3 March 2019, during its inaugural test flight.Image: SpaceX
Crew Dragon holding at 20 meters
Crew Dragon holding at 20 meters Crew Dragon holds at 20 meters from the station's forward docking point during its inaugural test flight on 3 March 2019.Image: SpaceX

With the sun getting low on the horizon as the station passed beneath Australia, Mission Control in Houston opted to wait for more uniform lighting, so Dragon paused until after sunset. The approach soon resumed with Dragon illuminating its target docking port with LED lighting, and the spacecraft made physical contact with the station at 05:51 EST (10:51 UTC). 

After soft capture, Dragon's docking hardware automatically sealed itself with the station, completing a hard docking. The crew pressurized the vestibule between the station and the spacecraft, performed leak checks, and opened Dragon's hatch at 8:07 EST, entering in oxygen masks to protect themselves in case any toxic gases leaked from the spacecraft's propellant system. Air samples collected from inside the capsule showed no signs of contamination.

Dragon will stay docked at the ISS until 8 March, when it returns to Earth and splashes down in the Atlantic Ocean off the Florida coast.

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