The unexpected sighting of an aircraft in the area near Wallops Island, Virginia forced Orbital ATK to cancel its planned launch Saturday of an unmanned cargo ship to the International Space Station.

Just moments before the Antares rocket was to blast off, carrying the Cygnus cargo ship at 7:37 am (1237 GMT), mission control called, "Abort, abort, abort!"

The next opportunity for launch is Sunday morning at 7:14.

The mission will be the eighth for Orbital ATK, which has a $1.9 billion-dollar contract with NASA to resupply the space station over several years.

The barrel-shaped Cygnus is packed with 7,400 pounds (3,356 kilograms) of food, supplies, equipment and science experiments.

Among them is a satellite that will test how bacteria grows in microgravity, and determine the minimum amount of antibiotic needed to stop its growth.

"Bacterial antibiotic resistance may pose a danger to astronauts in microgravity, where the immune response is weakened," NASA said.

"Scientists believe that the results of this experiment could help design effective countermeasures to protect astronauts' health during long-duration human space missions."

The US space agency hopes to send people to deep space in the coming decades, with a human mission to Mars sometime in the 2030s.

The current crew of six astronauts on duty at the space station include three Americans, one Italian and two Russians.

Source: AFP