US space agency NASA has postponed its fifth attempt to launch a huge stadium-sized balloon from Wanaka to collect scientific data from space.

The agency said the wind was again unsuitable to launch the balloon, described as the size of Dunedin's Forsyth Barr Stadium, at the latest scheduled launch time of 7.50am today.

"The wind direction today shifted toward the west, which ultimately led to today's cancellation after hours of waiting for the winds to align," it said.

Mission director Gabe Garde said sophisticated scientific instruments were connected to the parachute.

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"We were as close as we've ever been in this campaign for launching, but the wind direction simply wouldn't support taking the next steps of bringing the balloon out and beginning inflation operations," he said.

NASA will continue to assess the weather daily to determine if conditions will support a launch attempt.

If successful, the balloon could journey for 100 days, collecting scientific data from what the agency describes as "near space".