Giant balloon project deflated

Nasa is hoping the scientific payload has not been damaged

A giant balloon which scientists hope will usher in a new age of near space research has been forced back to Earth just hours after taking off from Australia.

The balloon sprang a leak and had to be landed by remote control about 250 kilometres (150 miles) from the launch site at Alice Springs.

The mishap is the latest problem for the Nasa project to circumnavigate the world and study near space after weeks of delays caused by bad weather. Nasa officials said they did not know the cause of the leak or the extent of any damage to the balloon, which was carrying a payload of scientific instruments.

"It developed a leak," said Nasa's Garry Woods. "That's about all we know at this stage. It could be something trivial, it could be something important."

A Nasa team has been sent to Alice Springs to recover the balloon and investigate the cause of the leak. But officials said they would try again, possibly in a week, with a replacement balloon.

Two-week mission

This first flight was intended to circumnavigate the globe over two weeks, passing over southern Africa and South America before returning to Australia, collecting data for a cosmic radiation experiment.

Pumpkin-shaped balloon

Nasa hopes the balloons could be a cheap alternative to satellites for research, with flights lasting up to 100 days.

The pumpkin-shaped Ultra-Long-Duration Balloon is designed to inflate gradually to the size of a football field as it approaches the edge of Earth's atmosphere.

The balloon is the largest single-cell, fully sealed balloon ever flown, with a fully inflated diameter of 58.5 metres (193 feet) and height of 35 metres (115 feet).

It is intended to travel at an altitude of 35 kilometres (20 miles), three to four times higher than passenger aircraft fly. The balloon would almost scrape the edge of space, riding above all but 1% of the Earth's atmosphere.