NG-19 CYGNUS DEPARTS ISS, Dec 22, 2023, Earth orbit, 8:05 am ET (NASA TV begins 7:45 am ET)

Update, December 20:  The Cygnus departure has been delayed one day to December 22 at 8:05 am ET. NASA TV coverage begins 7:45 am ET.  NASA did not say so, but the SpX-29 departure was delayed until tonight at 9:05 pm (December 20), which may have contributed to the decision to delay this one so ground and space crews have more time between the two operations. [UPDATE: The SpX-29 departure was delayed again and now is scheduled for December 21 at 5:05 pm ET.]

NASA did say Cygnus will not fire its engines to deorbit until January. NASA has a Spacecraft Fire Safety Experiment (SAFFIRE) experiment on Cygnus that will take place after it separates from ISS.

Original Entry: Northrop Grumman’s NG-19 Cygnus cargo resupply vehicle will depart from the International Space Station on December 21, 2023 at 10:30 am ET.  NASA TV coverage begins at 10:15 am ET.

Cygnus is not designed to survive reentry like SpaceX’s Cargo Dragon, so it is filled with trash which burns up along with the spacecraft as it reenters through Earth’s atmosphere.  Consequently there are no terrestrial weather-related constraints to this undocking as there are with the SpX-29 spacecraft whose return has been delayed by several days due to bad weather in Florida.

Cygnus berths to the ISS instead of docking like Cargo Dragon. Astronauts will use Canadarm2 to detach Cygnus from its berthing port and then release it into space at 10:30 am ET. Cygnus then will use its engines to move away from the ISS and fire the deorbit burn.