Photo
album: "Preparation for launching"
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We
are going to see the operations before the launch of the balloon that will carry
the CITADEL experiment measuring the electric field. Four specialists have come
for this experiment, we will call them the CITADEL team: the team leader,
Jean-Jacques Berthelier, researcher at GRI (Groupe de Recherches Ionosphériques);
Gérard Gogly his assistant, engineer at GRI; Jean-Pierre Legrand, engineer at
GRI; Roger Raymond specialist from the ballons-sondes service at CNES (Centre
National d'Études Spatiales). They are helped during the launch operations by
the members of the IONO team of the 23rd mission. A dozen of launches are
expected during this campaign. The main difficulty is the wind, its speed at
ground level must remain less than 10 km/h during the whole operation, i.e.
three hours at least. These conditions will be met about fifteen times during
the January-February 1973 period. The mean wind velocity during the campaign
will be 40 km/h and the maximum speed recorded on January 31st will be 220 km/h.
The absolute maximum wind speed recorded, at Dumont d'Urville, at the time (early
1973) was 310 km/h.
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The meteorologists have announced a
calm wind period, therefore favourable to launch a balloon. We are walking
towards the "pré" where is situated the launch pad. |
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A flat surface has been set in
front of the old rocket mounting hall which has been converted into a
mounting hall for the balloon payloads. A small captive balloon allows us
to ascertain the wind speed stays low. |
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The helium containers has been
carried near the hall to permit to inflate the balloons. The containers
are fitted by three in a frame. Each frame weighs 3,300 kg and contains 60
kg of helium, only, under very high pressure. |
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The launch pad is flat but very
coarse. Canvases are stretched on the ground before spreading the balloon
which has a very fragile envelope: a few hundredths of millimetre thick,
only. |
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We begin to inflate a balloon of
small dimensions, called auxiliary balloon. |
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The auxiliary balloon is now
inflated with 40 cubic metres of helium. It will carry the payload until
the launch of the main balloon which will be inflated afterwards. |
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The payload of the balloon is
composed of two parts. We see here the upper part called the technical
module. It permits the discharge of the ballast and the destruction, at
the end of the measurements, in cutting the cable which ties payload to
the balloon. |
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Jean-Pierre Legrand is beginning to
deploy the main balloon which was protected by a plastic envelope, a
member of the IONO team for the next winter over is helping him. |
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We can perceive, on the ground at
right, the small diameter tube for inflating the balloon, coupled to one
of the helium containers. |
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Jean-Pierre Legrand is finishing the spreading of the main balloon, which
has to be done very carefully. People who manipulate it have to wear silk
gloves in order not to injure the balloon skin.
|
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Gérard Gogly is doing the final
pre-flight checks of the ballast discharge and of destruction remote
controls. The ballast is made of lead pellets contained in eight cylinders
situated at the base of the service module. The reversed cone, under the
cylinders, modifies the trajectory of the pellets in order to send them
away from the measurement gondola situated below. We see, on the right,
the radar reflector which permit to follow the balloon during its ascent. |
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The main balloon is now entirely
spread on the protective canvases. We see, on foreground at left, the
fourth member of the CITADEL team: Roger Raymond. |
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Jean-Jacques Berthelier, crouched
on the left, and Gérard Gogly are doing the last checks of the second
part of the payload: the module which measures the electric field and
transmits the data to the ground station. |
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Everything is now ready to begin
the inflation of the main balloon. |
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The tube connected to the helium
container is terminated by an coupling piece which permits to connect it
to the inflating hose of the main balloon. Christian Sinet, member of the
IONO team of the 23rd mission holds this coupling piece during the
inflating operation. |
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The hose is inflated but the
balloon is still entirely on the round. |
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The main balloon is beginning to
rise. Jean-Pierre Legrand, helped by another operator, holds it and guides
it from the ground. |
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