SpaceX Crew Dragon undocks, Capsule to splash down.
Five days after docking to the International Space Station, the first crew-capable spacecraft from the United States in 8 years is set to end its inaugural mission, undocking from the ISS Friday morning ahead of reentry and splashdown in the Atlantic Ocean off the northeast coast of Florida.
Undocking occurred at 02:31 EST (0731 UTC) with five hours of free-flight ahead of Crew Dragon’s deorbit burn at 07:53 EST (1253 UTC) and splashdown at 08:45 EST (1345 UTC).
Once Crew Dragon is safely home, an immense amount of work will commence to analyze all of the data gathered during this test flight – a series of reviews that will lead to the critical In-Flight Abort test before culminating with the planned return of human launches to the United States with the Demo-2 mission of another SpaceX Crew Dragon later this year.
The departure of SpaceX’s first Crew Dragon from the Station follows five days of docked checkouts of the vehicle as well as removal of the cargo brought up to the ISS inside the capsule and repacking it with a limited amount of supplies for return to Earth.
After Crew Dragon was fully packed by NASA astronaut Anne McClain and Canadian Space Agency astronaut David Saint-Jacques, the two crewmembers closed and locked Dragon’s hatch Thursday afternoon, setting up the craft’s departure Friday morning.
Per the End Of Mission timeline provided by NASA, the first step in the Crew Dragon’s undocking came 3 hours before physical separation when the Station’s Solar Alpha Rotary Joints (SARJs) on both the port and starboard trusses were locked in place.
The SARJs are large rotating gears between the P3/P4 and S3/S4 truss elements that allow the Station’s power generating solar arrays to track the Sun as the Station constantly moves around the Earth in its orbit.
The P3/P4 truss (two truss elements built and launched as one) was delivered to the International Space Station on the STS-115 mission of Space Shuttle Atlantis in September 2006. The S3/S4 truss, a mirror of P3/P4, was taken to the Station on the STS-117 mission, also by Atlantis, in June 2007.
Locking down the SARJs prevents the Station’s arrays from moving – standard practice when Visiting Vehicles (VVs) approach and depart the Station – and provides a more stable environment for VV navigation systems, which are critical for safe proximity operations between the ISS and its various support craft.
After the SARJs were locked down, Anne McClain and David Saint-Jacques aboard the Station, NASA controllers at Mission Control Houston (MCC-H), and SpaceX controllers at MCC-X performed final system preparations for undocking.
A “Ready to undock” status came from the Station, MCC-H, and MCC-X around 02:07 EST (0707 UTC), about 24 minutes prior to physical separation of Crew Dragon.