An unmanned Cygnus cargo ship operated by Orbital ATK is poised to blast off toward the International Space Station on a frigid Saturday, carrying supplies to the six astronauts living in orbit.
The launch from Wallops Island, Virginia is scheduled for 7:37 am (1237 GMT), with temperatures forecast to be below freezing at around 25 Fahrenheit (-4 Celsius).
But the unseasonably cold temperatures are still within the acceptable range for an Antares rocket launch, which would be halted only if the weather dipped below 20 F (-6.6 C), launch managers said.
As of Friday afternoon, the forecast for Saturday's sunrise launch was "95 percent favorable," NASA said in a statement.
The mission is 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.
If the launch goes ahead as scheduled, the cargo ship should arrive at the orbiting outpost on Monday.
Astronauts will unload its contents, then repack it with trash so it can be shipped off in December and burn up upon re-entry into Earth's atmosphere.
The current crew of six astronauts on duty at the space station include three Americans, one Italian and two Russians.
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