Although ballooning itself may be centuries old, Mr Fossett's balloon was fitted with state-of-the-art technology. His craft was guided by the satellite-controlled global positioning system (GPS).

Air traffic controllers have guided the balloon on its course

The tiny cabin - or gondola - of Spirit of Freedom was constructed from a compound of lightweight materials including Kevlar and carbon fibres.

The balloon was also fitted with a range of high-tech radio and satellite communication equipment to maintain contact with the support team.

Onboard computers controlled the fuel burners which heated the helium in the balloon's envelope, maintaining height and allowing Mr Fossett to get some sleep.

Confined space

Despite the modern equipment, Mr Fossett had to cope with arduous living conditions. The cabin - barely 200 cubic feet (5.5 cubic metres) inside - was smaller than a prison cell.

Mr Fossett often had to wear a bulky oxygen mask, sleeping a maximum of four hours a day in "catnaps" of no more than 45 minutes.

He recently told ground control: "I keep my mask on even when eating, just taking it off to put in the next spoonful."

Ballooning breakthroughs

1785: First manned flight across the English Channel 1932: First manned flight into the stratosphere 1978: First transatlantic crossing 1981: First Pacific crossing 1998: First crossing of the South Atlantic and Indian Oceans 1999: First circumnavigation

His food supply consisted of dried, reheatable military-style rations and water. Toilet facilities were at best functional, consisting of a bottle and a bucket.

One of the riskiest parts of the flight was changing the fuel cylinders attached to the exterior of the cabin.

Mr Fossett had to climb outside the capsule in temperatures well below freezing to switch over the fuel tanks by hand.

In case of emergencies, the balloon was fitted with an Emergency Position Indicating Rescue Beacon (EPIRB) which could be activated by the pilot.

A risky moment came when Mr Fossett had to use all three burners to maintain height after running into fierce downdrafts about 1,550 miles (2,500 kilometres) east of New Zealand.

Mr Fossett also had to act quickly when a burner failed to switch off, causing the balloon to overheat and fly too high.

Essential training

To prepare for his challenge, Mr Fossett spent several weeks training at high altitudes in Colorado to acclimatise his body.

This included running three to five miles (5 km to 8 km) per day at altitudes of more than 12,000 feet (3,650 metres).

Such preparation helps the brain to adapt to performing complicated tasks in an environment where oxygen levels are lower than normal.

Previous Fossett attempts have ended in failure

Although Mr Fossett had to face the hardships at 28,000 feet (8,530 metres) alone, his flight would not have been possible without his ground support team.

As a balloonist can only control his craft's altitude, charting a course around the world - and its weather systems - is extremely difficult.

He has relied on a group of specialist meteorologists to predict altitudes with favourable winds and weather conditions.

Other key members of the support staff, based largely at Washington University in St Louis in the US, include balloon engineers and air-traffic control coordinators.