Leak causes early end to Nasa's Wanaka balloon mission
Nasa's Wanaka science balloon has sprung a leak over the Pacific Ocean. Plans are under way to bring it down early in South America.
Nasa communications spokesman Jeremy Eggers said the Nasa balloon team did not know what caused the leak.
"That's unknown. Nasa will form an investigation team to look at that very question. The data we collect as the mission continues will help us in that investigation."
Happily, scientists from the University of Chicago and the Colorado School of Mines are continuing to get data from their cosmic ray detector payload while the balloon is still afloat.
"On science—the science team continues to collect and download data from their instrument, which has been a bright spot indeed," Eggers aid.
The balloon was launched on its eighth attempt from Wanaka Airport on April 25, Anzac Day.
Eggers said about two hours after launch, the balloon pressurised normally at a predicted altitude of about 33.2 km (109,000 feet).
It maintained a stable float altitude for two days of flight, but on the third day it dropped in altitude during the night.
It later re-pressurised and returned to 33.2 km of altitude during the daytime.
Eggers said the balloon had flown through a cold storm and during past missions, these storms led to night time altitude variation.
On this flight, the balloon continued to lose altitude at night, then repressurise and rise back up in the day, which was not what it was designed to do.
"The balloon is designed to float at a stable altitude despite the heating and cooling of the day-night cycle," Nas balloon programme chief Debbie Fairbrother said.
"While cold storms do impact altitude, it's clear the balloon is no longer behaving as designed, and the data strongly suggests the balloon has developed a leak. This is an unfortunate development in our test flight, but we're gaining some important data from this mission that will apply to future flights."
Flight controllers at the Columbia Scientific Balloon Facility in Palestine, Texas, are monitoring the balloon over the Pacific Ocean.
There is ballast on board the gondola that can be dropped to slow the balloon's descent at night.
Once it crosses the ocean, Nasa will seek a safe area to terminate flight and recover the balloon and payload.
In the meantime, balloon flight data is still being collected and will be evaluated.
The data will be used to make design improvements to support future super pressure balloon missions.