NASA and Northrop Grumman have postponed the arrival of the new Cygnus XL cargo spacecraft at the International Space Station (ISS). The delay was announced after the vehicle's main engine experienced a problem during two scheduled orbit-raising burns, causing them to shut down prematurely.
The spacecraft, named the S.S. William ‘Willie’ C. McCool, was originally scheduled to be captured by the station's robotic arm on Wednesday morning. Mission managers are now reviewing the data to determine the cause of the engine anomaly and to plan the next steps for completing the rendezvous with the orbiting laboratory.
Key Takeaways
- Northrop Grumman's new Cygnus XL spacecraft has postponed its docking with the ISS.
- The delay is due to a main engine issue where two planned burns stopped earlier than expected.
- The spacecraft is carrying over 11,000 pounds of essential supplies and science experiments.
- This mission, NG-23, is the debut flight for the larger, higher-capacity Cygnus XL vehicle.
Propulsion System Anomaly Detected
The issue occurred during a critical phase of the spacecraft's journey to the ISS. In a statement released Tuesday evening, NASA confirmed that two engine burns designed to raise the Cygnus XL's orbit did not complete as planned. The burns "stopped earlier than planned," according to the agency.
Officials did not specify how long the burns were supposed to last or how much of the maneuver was completed before the shutdown. The root cause of the engine's underperformance is currently under investigation by engineers from both NASA and Northrop Grumman.
Despite the propulsion problem, NASA has assured that the situation is stable. "All other Cygnus XL systems are performing normally," the agency stated, indicating that the power, communications, and navigation systems remain fully functional. This stability gives the mission team time to analyze the problem and formulate a new plan to safely approach the station.
Rescheduled Rendezvous and Capture
The original plan involved NASA astronaut Jonny Kim using the station's Canadarm2 robotic arm to capture the Cygnus XL on Wednesday at 6:35 a.m. EDT. Fellow astronaut Zena Cardman was slated to assist with the operation. The capture maneuver requires the spacecraft to hold a stable position approximately 10 meters (about 33 feet) from the ISS.
With the delay, a new timeline for arrival has not yet been established. Mission control will wait for a full analysis of the engine issue before scheduling the remaining rendezvous maneuvers. The primary goal is to ensure the spacecraft can perform the necessary burns reliably and precisely to guarantee a safe approach.
The NG-23 Mission Launch
The NG-23 mission began on Sunday, September 14, with a successful launch aboard a SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station. The Cygnus XL separated from the rocket's second stage just over 14 minutes after liftoff. About 90 minutes into the flight, the vehicle successfully deployed its two large, circular solar arrays, a critical step for generating power for the journey.
Importance of the Cygnus XL Debut
A Larger Cargo Carrier
This mission marks the first flight of the Cygnus XL, an upgraded and larger version of Northrop Grumman's workhorse cargo vehicle. The new model is approximately 1.6 meters (5.2 feet) longer than its predecessor, a design change that significantly increases its payload capacity.
The Cygnus XL can transport about 2,600 pounds more cargo than the standard version, representing a 33 percent increase in volume. This enhancement is crucial for improving the efficiency of resupply missions to the space station.
"It’s really critical because we can deliver significantly more science as well as we’re able to deliver a lot more cargo per launch, really trying to drive down the cost per kilogram to NASA," said Ryan Tinter, vice president of Civil Space Systems for Northrop Grumman, before the launch.
Vital Supplies for the ISS
Onboard the NG-23 mission is a substantial cargo load of more than 11,000 pounds (4,990 kilograms). This includes crew supplies, scientific experiments, and critical hardware needed to maintain station operations.
Dina Contella, the deputy manager of NASA’s ISS Program, highlighted the importance of this specific delivery. "The NG-23 vehicle is packed with consumables, like nitrogen, oxygen, food and toilet parts," she noted. "We’re stocking up on these items since we were short over the past year and we’d like to have a good reserved for the future."
Cargo Manifest Highlights
- Crew Consumables: Food, water, and personal care items.
- Station Hardware: Spare parts for the urine processor and other life support systems.
- Gases: Tanks of nitrogen and oxygen to replenish the station's atmosphere.
- Science Investigations: A variety of experiments for the orbiting laboratory.
Navigating Supply Chain Challenges
The successful arrival of NG-23 is particularly important due to recent adjustments in NASA's cargo schedule. Earlier this year, the Cygnus spacecraft intended for the NG-22 mission was damaged during transport, forcing its launch to be postponed from its original June 2025 date.
To mitigate the supply gap, NASA reconfigured subsequent missions. The SpaceX CRS-32 cargo flight was loaded with extra food and water to bolster the station's reserves. Additionally, both the SpaceX CRS-33 and NG-23 missions were moved forward in the schedule.
Dana Weigel, manager of NASA's ISS Program, explained the strategy. "We like to have four months of supplies onboard. And the goal is really, if you have a problem with the next mission... you can make it to the mission after that." The successful launch and docking of SpaceX CRS-33 in late August helped stabilize the supply levels, but the arrival of NG-23 is needed to fully restore the desired four-month reserve.
As mission controllers work to resolve the Cygnus XL's engine issue, the crew aboard the ISS continues with their scientific research and daily operations, awaiting the arrival of their much-needed supplies.