HALO at the French National Archives in Paris for the annual ‘Nuit Blanche’ arts festival, October 2009.
The structure measures 22m x 3m, has a surface area of 560m2 and required 422 cubic meters of helium to fill. It has an internal air-pressurized, expandable balloon sleeve (darker band in image below) controlled by electric fans and pressure release valves. This internal balloon regulates the overall pressure which keeps the greater surface taught as the helium expands and contracts in changing weather conditions. 24 Pink fluorescent lights are suspended inside the HALO. The entire structure is operated by a remote control winch, rigged to a system of pulleys attached to four primary ballast points; a forklift, a truck, a car and 2 tons of sand. The lift and drag ratios are exceedingly large, the HALO could carry three or four people into the sky without any wind. In addition to the four main ballast points, 12 control cables each attached to 100kg concrete weights were manually adjusted as the HALO was raised. It can fly at 100m and requires a team of twenty people to install. It cost €30,000 to produce.