Gaia QM deployable sunshield set-up in the LSS
On 11 July the qualification model (QM) of Gaia's deployable sunshield was installed inside the Large Space Simulator (LSS) at ESTEC. Over the next days the set-up was finalized for the upcoming thermal vacuum/thermal balance (TV/TB) test, which is performed inside the LSS under simulated space conditions.
This view of the test set-up in the LSS main vacuum chamber, taken though the chamber door, shows the QM sunshield in fully deployed configuration during the preparations for the TV/TB test.
Around the sunshield is a large reflective foil, hanging in front of the opening where the beam of the Sun simulator enters the chamber, forming a mask. A window in the middle of the mask matches exactly the shape of the deployed sunshield. The mask allows light from the Sun simulator to impinge directly only onto the Sun side of the sunshield and blocks light that would otherwise pass the sunshield and reflect inside the vacuum chamber back onto the shadow side of the sunshield. (The shadow side of the sunshield is facing the camera in this photo.)
Also visible are the three masts of the zero-g kit (used to simulate weightlessness) that stand in front of the assembly, with the three rectangular panels of the QM sunshield each attached to a pulley and counterweight system on the masts.
The LSS chamber was closed on 20 July for the start of the TV/TB test.