Cygnus arrives at space station despite solar panel problem

Updated 6:15 p.m. Eastern with Northrop Grumman statement.

WASHINGTON — A Northrop Grumman Cygnus cargo spacecraft arrived at the International Space Station on Nov. 9, despite only having one of its two solar panels set up.

The Cygnus spacecraft, which flew the NG-18 cargo resupply mission for NASA, arrived at the station and was grabbed by the station’s robotic arm at 5:20 a.m. East. The arm docked the spacecraft on the station’s Unity module two and a half hours later.

An Antares rocket launched Cygnus on November 7, just hours later NASA reported that one of the two solar panels had failed after reaching orbit. Northrop said the spacecraft had enough power from one solar panel to run the vehicle, but NASA said engineers were studying any problems the undeployed array might have in gripping and docking the spacecraft.

NASA said in a Nov. 8 statement it would continue to approach the station by Cygnus. “Northrop Grumman and NASA have decided not to deploy the second solar panel after initial attempts to deploy it were unsuccessful,” the agency said.

Video from the ISS showed that while one of the circular arrays, designed to unfold like a fan, deployed as expected, the other appeared to have expanded only slightly. “The Cygnus team is gathering information about why the second array didn’t deploy as planned,” NASA said.

In a statement late Nov. 9, Northrop Grumman blamed the array’s failed deployment on the debris from the launch. “During a rocket stage separation, debris from an Antares acoustic blanket became trapped in one of the Cygnus solar panels, preventing it from opening,” said Cyrus Dhalla, vice president and general manager of tactical space systems at Northrop Grumman. The company did not explain how the debris got into the mechanism, something the company has not reported on previous Cygnus launches.

Cygnus delivered nearly 3,750 kilograms of cargo to the station, including crew supplies, scientific payloads and hardware. That hardware includes a bracket for solar panels that astronauts Josh Cassada and Frank Rubio will install outside the station during a Nov. 15 spacewalk as part of efforts to upgrade the station’s solar energy systems.

Cygnus is planned to remain attached to the station until the end of January, when it will leave the station, laden with waste, for a destructive return.