Hélios 1B

Hélios 1B was launched on 3 December 1999 by another Ariane 4, also co-manifested with another military satellite: Clementine.

Derived from SPOT 4, they retained the platform but were equipped with an attitude and orbit control system (SCAO).

This system allowed fine pointing of the shooting lens for several seconds, thus increasing the quality of the images.

The flywheels are then controlled by the SCAO which tries to follow a selection of the brightest stars in order to ensure the desired kinematics.

The satellite has been the victim of a loss of charge of an accumulator since May of the same year which in turn leads to the premature wear of the others.