European Probe's Sun Shield Deployed For The First Time

ESA's Gaia star-mapper has passed a critical test ahead of its launch in 2013: the spacecraft's sunshield has been deployed for the first time. Gaia's sunshield is an essential component of the mission. It keeps Gaia in shadow, maintaining the scientific instruments at a constant temperature of around -110 degrees centigrade.

ESA Photo

The sunshield is about 10 m across, which is too large for the launch vehicle fairing, so it has been built with a dozen folding panels that will be deployed after launch. Since the sunshield is designed for the weightlessness of space, it cannot support its own weight on Earth. So, during this test at Astrium in Toulouse, France, support cables and counterweights simulated weightless conditions and provided a realistic trial.

During its expected lifetime of five years, Gaia will take a census of a billion stars - roughly 1% of all of the stars in our Galaxy. It will observe each star about 70 times, each time recording its brightness, colour and, most importantly, its position. By comparing Gaia's series of exquisite observations, astronomers will precisely measure the apparent movement of each star across the heavens, enabling them to determine its distance and true motion through space. The unprecedented results will allow astronomers to trace the history of the Milky Way.

Before the 2013 launch, some of the solar array panels needed to generate power will be fixed to the sunshield. The rest will be placed on the bottom of the spacecraft.

FMI: www.esa.int