NASA is monitoring the weather in Central Otago as it looks to launch another super-pressure scientific balloon.
Saturday is the first day of the window for the launch from Wanaka Airport where a dedicated launch platform has been constructed.
The balloon is about the size of the Forsyth-Barr Stadium in Dunedin, when fully inflated and is made from polyethylene film, similar to sandwich bags, but stronger and more durable.
NASA's scientific balloons offer low-cost, near-space access for scientific payloads.
The first balloon launched from Wanaka Airport in 2015 achieved 32 days of flight, with 46 days was notched up in 2016.
It's hoped the flight this year will be longer. The current record for a NASA super-pressure balloon flight is 54 days.
NASA is not expecting the first day to be the one for the launch. Forecast winds are variable and not in the necessary direction.
Winds need to be light and flowing in a reliably easterly direction.
"As with previous campaigns, our team will assess weather daily to determine if the conditions are right to support a launch attempt," says Gabe Garde, mission manager for this year's flight campaign.
The acting US Ambassador to New Zealand, Charge d'Affaires Candy Green, paid a visit to Wanaka Airport on Thursday to see the balloon operation.
After launch, the balloon will ascend to an altitude of 33.5 km where the stratospheric winds will propel it at speeds up to and exceeding 100 knots through the heating and cooling of the day-night cycle around the southern hemisphere.
While the ongoing testing and development of the balloon is the primary focus of this year's mission, the team is flying the University of Chicago's Extreme Universe Space Observatory (EUSO) as payload.
The high-energy cosmic ray particle astrophysics payload will test a fluorescence detector and its supporting technologies. This is a precursor for a mission being planned to launch the EUSO telescope to and install it on the International Space Station.