UPDATED 9.39AM A change in the weather has led NASA to cancel its super pressure balloon launch in Wanaka this morning.

Scientists have been "flight ready" since the start of the month, but they've yet to get the windless conditions that will allow them to launch the balloon on its 100-day journey to investigate black holes and gamma rays.

Campaign Manager Dwayne Orr said earlier this morning they were still confident they could fly the balloon.

"The problem was right when I was looking and making a decision to go and lay out the balloon the surface wind kicked up above six knots to seven."

Mr Orr said this meant they were no longer getting the stability they needed, so it wasn't worth risking the very expensive balloon.

He said so far tomorrow doesn't look good either, so Thursday could be show day, but it's marginal.

LISTEN ABOVE: NASA's balloon programme chief Debbie Fairbrother speaks to Andrew Dickens

Ealier, balloon programme chief Debbie Fairbrother said whether the balloon was launched today or not, they would stay positive.

"The team's used to this, so while we don't like waiting around, waiting on weather, we know we've got to have the right conditions for this balloon."

Ms Fairbrother told Andrew Dickens when the launch all goes to plan, they're hoping to have it in the air for as long as possible, and aren't sure where it will then land.

"We've got approval for Argentina, Australia and New Zealand to terminate, and really it depends on mother nature so wherever the winds will take us will determine where we'll terminate."