Northrop Grumman's latest Cygnus XL cargo spacecraft, designated NG-23 and named S.S. William 'Willie' McCool, was launched from Cape Canaveral aboard a SpaceX Falcon 9 rocket on September 16, 2025, carrying over 11,000 pounds of supplies to the ISS.

This mission marks the 22nd Cygnus flight under NASA's Commercial Resupply Services 2 contract, delivering critical scientific experiments, spare parts, and crew provisions to the station.

The cargo includes essential items such as nitrogen, oxygen, food, and scientific materials, including experiments on cryogenic storage and microgravity drug development.

The spacecraft was scheduled to dock with the ISS on September 17, 2025, with capture planned by the station's robotic arm around 6:35 a.m. EDT and berthing beginning at 8 a.m. EDT.

However, the docking has been delayed due to an engine shutdown issue during orbit-raising burns, caused by a thruster malfunction, which remains under investigation.

Despite the engine problem, all other systems on Cygnus XL are functioning normally, and NASA is reviewing a new arrival date for the spacecraft.

The delay impacts NASA's cargo schedule and underscores ongoing challenges with ISS resupply missions, especially following earlier damage to a Cygnus spacecraft this year.

To mitigate the delay, NASA has adjusted its cargo schedule, including accelerating the launch of SpaceX's CRS-33 mission, which successfully docked on August 25, 2025.

NASA plans to un-berth the Cygnus in November to make room for a crewed Soyuz spacecraft, with options to either re-berth or dispose of the spacecraft as trash if necessary.

Cygnus XL will remain attached until March 2026 before it burns up in Earth's atmosphere, serving as an expendable resupply vehicle alongside Russia's Progress, while SpaceX's Dragon remains reusable.

This mission is part of Northrop Grumman's ongoing efforts, which have included 20 successful Cygnus flights since the company's earlier vehicle was damaged and grounded for repairs.

The Falcon 9 rocket used for this launch, with tail number B1094, completed its fourth flight and successfully landed at Landing Zone 2 after launch on September 14, 2025.