announced this week that it successfully launched a on Dec. 28 from an NSF hub in Antarctica. Made of a lightweight polyethylene film about the thickness of plastic food wrap, the 7-million-cubic-ft. super-pressure balloon climbed to what NASA called a float altitude of 110,000 feet, which is three to four times higher than the altitude that commercial jets hit.

The balloon is still up there, holding its altitude of nearly 21 miles above the Earth. According to NASA, scientists hope future will carry a 1-ton scientific instrument aloft and keep it up there for 100 days or more.

"This flight test is a very important step forward in building a new capability for scientific ballooning based on sound engineering and operational development," said W. Vernon Jones, senior scientist for suborbital research at NASA, in a statement. "The team has further work to do to enable the super-pressure balloon to lift a 1-ton instrument to a float altitude of 110,000 feet, but the team has demonstrated they are on the right path."

NASA reports that the prototype is the largest single-cell, super-pressure, fully sealed balloon ever flown. And the space agency said in an online alert that scientists there expect to create a 22 million-cubic-ft. balloon -- a balloon about three times the size of the prototype.

Scientists are focusing on building the giant balloons because of their ability to handle extended missions aloft and because the scientific instruments that they carry can be launched, retrieved and then even launched again.