The Greenpeace balloon
The Greenpeace balloon can carry three people - a pilot and two passengers, such as a campaigner and photographer or parachutist. Three more people are needed to form the ground crew.
The balloon can only be launched in low winds (up to 10 knots). In many parts of the world, this means it can only be flown two hours after sunrise and two hours before sunset.
This is because during the day the sun heats up the atmosphere and creates thermals that make balloon flying dangerous. In winter months, when the sun's heat is less powerful, there is a better chance of making daytime flights.
The balloon can stay airborne for a maximum of two hours in normal conditions (a cool temperature under 2000 metres above sea level).
There are two types of balloon flight - free or tethered.
During free flights, once launched the balloon is carried in the general direction of the wind.
The pilot can steer the balloon to an extent by taking advantage of different wind directions at higher and lower altitudes.
For tethered flights the wind speed must be less than for free flights (about 8 knots maximum), because the balloon is in effect resisting the wind and the hot air could be blown out of it, causing it to sink rapidly.
Historic Greenpeace balloon flights include flights over the Berlin wall in 1983, over the US Nevada nuclear test site in 1987 and over the Taj Mahal during the nuclear testing protest in India in 1998.
Greenpeace uses balloons for a variety of campaign purposes, such as for hanging banners, taking pictures of environmental crimes and measurements of airborne pollution from and as a platform for parachute jumps.
1 Envelope CAMERON including scoop, type Sphere 105
1 Nacelle CAMERON Aristocrat (Basket)
1 CAMERON burner MK 4 Super (including 4 karabiners)
2 Standard Worthington Cylinders
3 Master Worthington Cylinders
1Remorque WESTFALIA - (Trailer)
Campaign director of Greenpeace Canada, Jo Dufay describes her balloon flight over Quebec City, Canada on 20 April 2001:
As the balloon rose past the citadel in Quebec City, the wind caught the top, stretching the balloon.
This meant it was under-inflated, and we started to plummet. I looked down through the basket of seemingly flimsy wicker.
I wouldn't trust this to hold my laundry, I thought, realising it was the only thing between me and the St Lawrence River below.
Suddenly we were rising again, as Franz, the pilot, turned the flame to a roar. The balloon swelled, the map of the world luminous on the balloon as we looked up through the inside.
With the flame reduced again, we sailed peacefully over the site of the Summit of the Americas, the balloon carrying a message for world leaders -"Stop Climate Change".
In the sudden quiet we heard the Summit security helicopter - they were on to us.