.jpg) NG-23 shortly before it was captured by theCanadarm2 | |
| Names | CRS NG-23 |
|---|---|
| Mission type | ISS resupply |
| Operator | Northrop Grumman |
| Mission duration | 65 days, 12 hours and 17 minutes(in progress) 6 months (planned) |
| Spacecraft properties | |
| Spacecraft | S.S.William "Willie" C. McCool |
| Spacecraft type | Cygnus XL |
| Manufacturer |
|
| Launch mass | 10,200 kg (22,500 lb) |
| Start of mission | |
| Launch date | September 14, 2025, 22:11:49 UTC (6:11:49 pm EDT) |
| Rocket | Falcon 9 Block 5 (B1094‑4) |
| Launch site | Cape Canaveral,SLC‑40 |
| Contractor | SpaceX |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Inclination | 51.66° |
| Berthing atISS | |
| Berthing port | Unity nadir |
| RMS capture | September 18, 2025, 11:24 UTC |
| Berthing date | September 18, 2025, 14:10 UTC |
| Unberthing date | November 2025 (planned) |
| Time berthed | 61 days, 20 hours and 19 minutes(in progress) |
| Reberthing with ISS | |
| Reberthing port | Unity nadir |
| Reberthing date | November 2025 (planned) |
| Unreberthing date | March 2026 (planned) |
| RMS release | March 2026 (planned) |
| Cargo | |
| Mass | 4,911 kg (10,827 lb)[1] |
 Mission patch | |
NG-23 is a cargo resupply mission to theInternational Space Station (ISS) under NASA'sCommercial Resupply Services (CRS) contract. Operated byNorthrop Grumman, the flight successfully launched on September 14, 2025, aboard aFalcon 9 Block 5 rocket. The spacecraft is namedS.S.William "Willie" C. McCool in honor of the NASA astronaut who died in theSpace ShuttleColumbia disaster in 2003.[2]
The mission debuted theCygnus XL spacecraft configuration, featuring a pressurized cargo module measuring 7.89 meters (25.9 ft) in length, with a payload capacity of 5,000 kilograms (11,000 lb), an increase of 19.5%, and a pressurized cargo volume of 36 cubic metres (1,300 cu ft), an increase of 15.5%.[3][4]
It is the third Cygnus launch on a Falcon 9, arranged after Northrop Grumman'sAntares 230+ was retired in 2023 due to supply chain disruptions stemming from theRussian invasion of Ukraine. A successor, theAntares 300, is under development with no Russian or Ukrainian components.[5]
TheCygnus cargo spacecraft was developed byOrbital Sciences Corporation with partial funding from NASA'sCommercial Orbital Transportation Services (COTS) program. It pairs a pressurized cargo module built byThales Alenia Space—derived from theMulti-Purpose Logistics Module used on theSpace Shuttle—with a service module based on Orbital'sGEOStar satellite bus.
The firstStandard Cygnus flew in 2013, followed by the largerEnhanced Cygnus in 2015. Orbital Sciences becameOrbital ATK in 2015 and was acquired by Northrop Grumman in 2018. Since then, Northrop Grumman has continued CRS operations. NG-23 is the eleventh Cygnus mission under theCRS-2 contract.[6]
The Pressurized Cargo Module (PCM) was manufactured byThales Alenia Space inTurin, Italy and assembly of the service module for the NG-23 spacecraft took place at Northrop Grumman's facility inDulles, Virginia. The service module was integrated with the pressurized cargo module at theSpace Systems Processing Facility at theKennedy Space Center.[6]
The flight marks the first launch of theCygnus XL configuration, designed to increase cargo capacity and volume for future Commercial Resupply Services (CRS) missions.[3] NASA and Northrop Grumman conducted additional certification work to assess the thermal and life-support impacts of the larger design, as well as to evaluate how theCanadarm2 could best accommodate the heavier and longer vehicle.[7]
NG-23 lifted off on September 14, 2025, at 22:11:49 UTC (6:11:49 pm EDT) aboard aFalcon 9 Block 5 rocket fromSpace Launch Complex 40 at theCape Canaveral Space Force Station.[5] After reaching orbit, the Cygnus XL spacecraft began its planned engine burns to rendezvous with the International Space Station, but two burns shut down early due to a conservative software safeguard. NASA postponed the September 17 docking while engineers worked on an alternate plan, keeping Cygnus at a safe distance.[8][9] On September 18, astronautJonny Kim, with help fromZena Cardman, captured the spacecraft using Canadarm2 at 11:24 UTC. Ground teams at Northrop Grumman's control center in Dulles and NASA'sJohnson Space Center in Houston, Texas completed berthing a few hours later.[7][10]
NG-23 is planned to remain at the station for 200 days, until March 2026. However, the spacecraft will need to be unberthed in mid-November 2025 and held on Canadarm2 away from the docking port, as its position would otherwise interfere with the approach corridor forSoyuz MS-28 at theRassvet nadir docking port. If this maneuver cannot be carried out, NG-23 would be required to depart in November.[7]
TheCygnus XL is equipped with "Extend the Lab" capabilities, allowing experiments to be conducted within the spacecraft by delivering power to the experiments, enabling science to take place without unloading them. Cygnus is also capable of performing ISSreboosts if requested by NASA. After unberthing, but before its controlled destructive reentry, the Cygnus XL will conduct a secondary mission to test the PALOMINOelectrospray thruster subsystem developed by Revolution Space.[11]
NG-23 was advanced in the launch schedule by four months after the indefinite delay ofCygnus NG-22, whose pressurized cargo module was damaged during transportation to the launch site in early 2025. Following inspections, NASA and Northrop Grumman replaced NG-22 with the next available vehicle, NG-23, which launched in September 2025.[12][13][14]
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