First Flight of Cygnus XL Boosts ISS Resupply with 33% More Capacity and New Features

In a major step forward for space logistics, Northrop Grumman’s first Cygnus XL spacecraft—the S.S. William “Willie” C. McCool—has successfully lifted off to the International Space Station aboard a SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station in Florida. The mission, designated NG-23 under NASA’s Commercial Resupply Services programme, marks the inaugural flight of the enlarged and more capable Cygnus XL vehicle.

Key Details of the Mission

The spacecraft launched at 6:11 p.m. EDT on September 14, 2025, carrying more than 11,000 pounds (≈5,000 kg) of equipment, science experiments and supplies for Expedition 73 astronauts aboard the ISS. It is scheduled to arrive on September 17, 2025, when NASA astronaut Jonny Kim, assisted by Zena Cardman, will operate the Canadarm2 robotic arm to capture the craft and berth it to the Unity module’s Earth-facing port.

What’s New with Cygnus XL

The XL variant brings several upgrades compared with its predecessor:

• 33% greater cargo capacity, with the ability to carry up to 5,000 kg of ascent cargo.

• A larger pressurised cargo module, offering about 38 cubic metres of volume and standing nearly 8 metres tall.

• Improved solar power, using twin UltraFlex arrays with gallium arsenide solar cells.

• Continued reboost capability, allowing the spacecraft to help maintain the ISS’s orbital altitude, a role Cygnus has supported since 2022.

Scientific Payload and Other Cargo

Alongside crew supplies, the Cygnus XL is delivering a diverse range of research material and station hardware, including:

• Semiconductor crystal growth experiments to study advanced materials.

• Equipment for testing cryogenic fuel storage technologies in space.

• A UV light water purification system to reduce microbial growth aboard the station.

• Pharmaceutical crystal growth studies with potential applications for cancer treatment.

• Spare components for station life support, power management, air circulation and structural systems.

Mission Timeline and Duration

The spacecraft is expected to stay attached to the station until around March 2026. It will temporarily undock in November 2025 to clear the Unity port for the arrival of Russia’s Soyuz MS-28 spacecraft. At the end of its mission, Cygnus will be packed with station refuse and burn up safely during re-entry into Earth’s atmosphere.

Honouring a Fallen Astronaut

As with previous missions, this Cygnus is named in honour of a space pioneer. The NG-23 vehicle commemorates William “Willie” McCool, the pilot of Space Shuttle Columbia’s STS-107 mission in 2003, who lost his life in the Columbia accident.

A New Chapter in Commercial Spaceflight

Since its debut in 2013, the Cygnus programme has delivered more than 71,000 kg (≈148,000 pounds) of cargo to the ISS. With the introduction of the XL variant, Northrop Grumman strengthens its role in advancing a commercial space economy, giving NASA and its partners more efficient and flexible ways to sustain the orbiting laboratory while preparing for future exploration missions beyond low Earth orbit.