Falcon 9 cargo spacecraft launched Northrop Grumman Swan It was sent to the International Space Station on August 4, but the spacecraft experienced problems that delayed the maneuvers needed to reach the station.

Falcon 9 It lifted off from Space Launch Complex 40 in Cape Canaveral, Florida, at 11:02 a.m. EST. The launch appeared to be going according to plan, with the Cygnus spacecraft separating from the Falcon superstructure in low Earth orbit about 15 minutes after liftoff. The liftoff, which was delayed a day due to poor weather, avoided the effects of Tropical Storm Debbie to the west and at one point had only a 10% chance of acceptable launch weather.

There were no updates from NASA or Northrop Grumman after the spacecraft left for several hours, but communications between ISS astronauts and mission control indicated that the spacecraft had not performed its initial burn to raise its orbit to allow it to arrive at the station in the early hours of August 6.

In a NASA statement released about six hours after liftoff, the agency said the spacecraft failed to perform a maneuver called the target altitude burn, or TB1, 42 minutes after liftoff “due to a late entry into the burn sequence.” The burn was delayed by 50 minutes, but it also failed due to a “slightly low starting pressure condition” in the engine.

“Cygnus is at a safe altitude and Northrop Grumman engineers are working on a new burn and orbit plan,” NASA said, adding that the plan should still allow Cygnus to arrive for capture by the station’s robotic arm at 3:10 a.m. on Aug. 6. NASA added that the solar panel installation was completed about three hours after launch.

Cygnus is carrying 3,857 kilograms of cargo, including 1,560 kilograms of automotive equipment, 1,220 kilograms of scientific research and 1,021 kilograms of crew belongings. The hardware includes “critical spare parts and new hardware,” ranging from a replacement pump assembly for the urine treatment system to a modification kit for the installation, NASA’s ISS Operations Integration Manager Bill Spetch said in a briefing on Aug. 2. The ISS’s final solar array is set to be operational on the station in 2025.

The scientific workload includes experiments to investigate how spaceflight affects the DNA of microscopic organisms and research into stem cells, which could be used to treat blood disorders. Also on board is what Megan Everett, NASA’s deputy principal scientist for the ISS, called a “STEMonstration,” or a teaching experiment to demonstrate centripetal force using balloon objects, in a briefing.

The crew supplies include some supplies for astronauts Butch Wilmore and Suna Williams, who spent nearly two months on the station during the CST-100 Starliner Crew Flight Test mission. “We want to keep our options open,” Spetch said, referring to the mission’s uncertain return date. That includes clothing removed from the Starliner just before launch to make room for spare parts to assemble the station’s urine processor. “We have clothes, we have special food supplies for them, thank you.”

However, there are no Crew Dragon suits on Cygnus for Williams and Wilmore, amid speculation that NASA is considering returning the two astronauts home on Crew Dragon instead of Starliner. “We’ll have to figure that out later,” he said.

The launch was the second of three Falcon 9 missions Northrop Grumman has conducted to launch Cygnus while working with Firefly Aerospace on a new version of the Antares Antares 330 rocket. This version replaces the Ukrainian first stage and Russian engines with a Firefly-designed platform powered by Miranda’s engines.

Ryan Tintner, Northrop Grumman’s vice president of civil space systems, declined to comment when asked whether the new Antares would be ready for Cygnus missions after the Falcon 9 launch of the NG-22 mission, currently scheduled for spring 2025. “I don’t think I can give a specific timeline,” he said of Antares’ readiness. “It’s progressing as planned and we’re on the right track.”

“Cygnus is launch vehicle agnostic,” he added. “We will continue to work with NASA and then determine the right launch vehicle.”