Northrop spacecraft's ISS cargo delivery set for Thursday after software hiccup

WASHINGTON, Sept 17 (Reuters) - NASA on Wednesday night resumed plans to moor an uncrewed cargo craft to the International Space Station after resolving an early engine-shutdown issue it said was caused by a "conservative safeguard" in the vehicle's software settings.

The arrival of the Northrop Grumman-built Cygnus XL spacecraft, carrying 11,000 pounds (4,990 kg) of cargo and science supplies, is set for around 7:18 a.m. EDT (1118 GMT) Thursday, the U.S. space agency said.

The spacecraft is a larger variant of Northrop's Cygnus cargo vessel and was launched for the first time on Sunday from Florida aboard a SpaceX rocket, setting off on a routine mission to autonomously deliver the supplies to the ISS and its international crew of seven astronauts.

On Tuesday, the spacecraft's main engine shut down earlier than planned as it was raising its orbit to rendezvous with the ISS, leading NASA to call off a planned arrival on Wednesday morning.

"Cygnus XL’s trajectory placed the spacecraft a safe distance behind the space station while engineers assessed the spacecraft and developed its alternate burn plan," NASA said in a Wednesday night statement.

The agency said "an early warning system initiated a shutdown command and ended the main engine burn because of a conservative safeguard in the software settings."

Once Cygnus approaches the ISS early Thursday morning, NASA astronaut Jonny Kim will use the station's 57-foot-long exterior robotic arm, the Canadian Space Agency’s Canadarm2, to capture the spacecraft and park it at an entry port. It will remain there until March 2026.

Northrop's Cygnus and the Dragon capsule from Elon Musk's SpaceX are the two spacecraft relied on by NASA to ferry supplies and research experiments to and from the ISS, a football field-sized laboratory that has orbited Earth for more than 25 years.