Inflating the balloon
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The year 2000 experience

The year 2000 experience ended in failure: caught in a gust of wind the envelope was torn off the hands of the operators during the inflating, it flew away under the disappointed eyes of the audience.
In the fall of the same year a much safer method had been designed and put into practise.
Still improved it was used on the 8th of June 2000.

The inflating pad

It is close to the launching pad, far from high buildings, sheltered from the wind as far as possible.
The envelope is utterly fragile: a nail, a pebble or a sharp angle can start a tear. Operators wear medical latex gloves.


It is a rare, non flamable gas. It is far lighter than air, fossile and expensive. The bottle (see picture) is equipped with a relief valve, two manometers which permit to lower the 200 bar pressure to the atmospheric pressure. The bottle provided the 7.4 metres cubes needed for the operation.

Inflating procedure

The operation is long: about 40 mn. The pipe connected with the relief-valve is connected with the inflating mantle and held by hand. Meanwhile the envelope which slowly inflates is held by two female operators. Helium piles up in the upper part of the envelope. Notice the surgical gloves.

Allowing for the tare

The gondola weighs 2180 gr. To get a 5m/s climbing speed and a bursting at 33000 m, the envelope must be inflated so as to lift a weight of 3990 gr exactly. This tare (about 4kg) consists of a small cubitainer containing water.
The balance is obtained by adding or releasing helium.

The launching

The supporting string is strongly tied to the latex cuff down the envelope.
Thus the envelope is shut and helium can't leak.
The envelope is launched little by little, taking the parachute. The gondola is taken near the middle of the launching pad to move the balloon away from the screen.
See the flight