ESA Science & Technology - Herschel moves to the Large Space Simulator

On Monday 27 October the Herschel spacecraft flight model was transferred from the HYDRA facility - where it has been subjected to functional testing and cryostat filling operations - into the clean room next to the LSS.

Figure 1. The Herschel spacecraft in a clean room at ESTEC prior to being lifted into the LSS using the three-prong lifting 'claw' (see above). In the photograph on the right the spacecraft is positioned beneath the claw. A protective foil covers the sensitive surface of the telescope. Credit: ESA

The next day the 3.5 tonne spacecraft was raised into position above the LSS using the custom-built three-prong lifting frame. Herschel's large size made manoeuvring the spacecraft a challenging operation with clearances of only a few centimetres in some cases.

Figure 2. The spacecraft is raised (above left) and guided towards the roof of the LSS (right, top and bottom). Credit: ESA

Once in position the spacecraft was carefully lowered into place in front of the custom-build radiator which simulates the thermal radiation of the Sun onto the large solar array and the sunshield, similar to the conditions at L2 – the operational orbit for Herschel.

Figure 3: This custom-built radiator in the LSS simulates the thermal radiation of the Sun at L2. Credit: ESA	Figure 4: Herschel is lowered into the LSS. Credit: ESA

Final preparations are now underway for the thermal balance and thermal vacuum tests which are due to begin on 11 November.

During these tests the second system operations verification test (SOVT-2) will take place. This will include 5 days of operations of the spacecraft from the mission control center in ESOC mostly filled with operational tests of all the Herschel instruments.

The thermal balance and thermal vacuum tests are expected to continue until 10 December.