SpaceX Falcon 9 launched Northrop Grumman's new Cygnus XL cargo spacecraft on its debut mission NG-23, to the International Space Station (ISS) on Sunday, Sept. 14, at 2211 UTC from Cape Canaveral Space Force Station's Space Launch Complex 40.
The Falcon 9 rocket's first-stage booster B1094 which is on its fourth flight, successfully returned to Landing Zone 2 at Cape Canaveral about eight minutes after liftoff as planned. Meanwhile Cygnus XL separated from the Falcon 9 second stage in orbit about 15 minutes after liftoff, on its way to the space station.
"@NorthropGrumman's Cygnus XL cargo craft deployed its cymbal-shaped UltraFlex solar arrays about an hour-and-a-half after launch today powering the spacecraft during its flight to the station," NASA ISS page wrote on X.
The NG-23 mission marks the first flight of the Cygnus XL, a significantly larger and more capable freighter capable of carrying 4,990 kilograms(kg) of cargo, a 33% increase over previous models. The previous iteration hauled about 3,855 kg pounds of cargo to the ISS.
The spacecraft, named S.S. William "Willie" McCool in honor of the Columbia STS-107 pilot, will be captured by the station's Canadarm2 robotic arm and berthed to the Unity module on Wednesday, September 17, 2025 at about 1035 UTC.
NG-23 is Northrop Grumman's 23rd resupply mission to the ISS under NASA's Commercial Resupply Services-2 contract. The Cygnus XL's increased capacity allows for more science and cargo delivery, including materials for semiconductor and pharmaceutical crystal production, equipment for cryogenic fuel tank improvements, and a specialized UV light system to combat microbial growth in the station's water systems.
Among the supplies packed aboard the freighter are "materials to produce semiconductor crystals in space and equipment to develop improvements for cryogenic fuel tanks," NASA officials wrote in a statement. "The spacecraft also will deliver a specialized UV light system to prevent the growth of microbe communities that form in water systems and supplies to produce pharmaceutical crystals that could treat cancer and other diseases."
The spacecraft will remain docked to the ISS until at least March 2026, after which it will be filled with waste and deorbited to burn up in Earth's atmosphere. Unlike SpaceX's reusable Dragon capsule, Cygnus is a disposable spacecraft.
The Cygnus XL's larger size necessitates temporary unberthing from the ISS during the approach of a crewed Russian Soyuz spacecraft in November 2025 for safety reasons.
NG-23 is the first Cygnus launch since August 2024, when NG-21 took flight. NG-22 was supposed to follow in January of this year but was delayed to June due to avionics issues. Then, in late March, NASA announced that NG-22 had been called off, as a result of damage the Cygnus incurred during transport to the launch site.
