Northrop Grumman's Cygnus XL cargo ship, which is transporting over 11,000 pounds of essential equipment and supplies to the International Space Station (ISS), experienced two premature engine shutdowns on Tuesday. This unexpected malfunction led flight controllers to pause a meticulously planned rendezvous, causing a delay in the ship's arrival at the ISS. Currently, the exact cause of the engine issues remains unclear, and it is uncertain when the spacecraft will successfully complete its rendezvous, pending the resolution of the problem and the development of an alternative burn plan.
Early Tuesday morning, the main engine of the Cygnus XL shut down prematurely during two critical burns intended to raise the spacecraft's orbit for rendezvous with the ISS, as reported by NASA in a blog post. Notably, all other systems aboard the Cygnus XL are functioning normally. However, further details regarding the cause of the shutdown have not been disclosed at this time.
The Cygnus XL was launched on Sunday from Cape Canaveral atop a SpaceX Falcon 9 rocket. The cargo ship was successfully released from the booster's upper stage as planned, initiating a precisely orchestrated sequence of rocket firings aimed at catching up with the space station. Unlike SpaceX’s cargo Dragon and Russian Progress freighters, which autonomously dock with the ISS, the Cygnus is designed to be captured by the station's robotic arm and subsequently pulled in for berthing.
The planned capture of the Cygnus XL was scheduled for Wednesday morning; however, this operation is now on hold while engineers investigate the engine issue and devise an alternate rendezvous strategy. Consequently, the arrival of the Cygnus XL at the ISS, originally set for Wednesday, September 17, is under review, with NASA indicating that a new arrival date and time will be determined as the situation develops.
The launch of the Cygnus XL marks a significant milestone for Northrop Grumman, especially after a previous model of the Cygnus was damaged during transit from a European subcontractor to Cape Canaveral. That particular vehicle remains grounded as it awaits analysis and repairs. Sunday’s launch was the third of at least four SpaceX flights contracted by Northrop Grumman, as the company works to recover from the transit setback and advance its development of a new booster.
This launch also signifies the maiden flight of the Cygnus XL, an upgraded cargo ship that has been lengthened to enhance its cargo capacity for missions to the ISS. According to Dina Contella, deputy manager of the space station program for NASA, this new version is approximately 1.6 meters (5 feet) longer and capable of carrying around 2,600 additional pounds of cargo. For its inaugural flight, the Cygnus XL is loaded with over five-and-a-half tons of vital spare parts, research materials, and crew supplies, including festive treats for the station's crew.
Contella emphasized the significance of this mission by stating, “The Cygnus is packed with consumables, such as nitrogen, oxygen, food, and toilet parts, along with a substantial number of spare parts necessary for critical systems.” She added that the ISS has faced shortages over the past year, highlighting the need to stockpile these essential items for future operations. NASA funds cargo delivery flights using both Cygnus and Dragon spacecraft. To date, SpaceX has successfully completed 32 Dragon resupply missions, while Northrop Grumman has achieved 20 successful flights, excluding the current mission. Both companies have experienced one in-flight failure each due to launch mishaps early in the commercial resupply program.
