Herschel mated with Ariane 5 ECA Launcher

11 May 2009

Move to the final assembly building

On Wednesday 29 April the Herschel spacecraft was transported from the S5B building to the final assembly building (Bâtiment d'Assemblage Final, or BAF) at the Ariane launch site of the European spaceport in Kourou. For this transport, over about 10 kilometres, the Herschel spacecraft was placed inside the payload transport container (Conteneur Charge Utile 3, or CCU3) at the S5B building.

The CCU3 transport container was used to maintain a cleanroom environment during the transport to the BAF. Upon arrival at the BAF, the CCU3 container was placed inside the BAF airlock. This 47-m-high part of the BAF building at its top has an opening into the adjacent 90-m-high hall where the Ariane 5 ECA launcher stands.

Herschel mating with launcher

After ensuring cleanroom conditions inside the BAF airlock, on the next morning the spacecraft was rolled out of the CCU3 container. The launcher ring adapter, which was already installed at the base of the spacecraft's service module, was disconnected from the raising cylinder on the CCU3 pallet.

With the spacecraft secured by the three arms of the vertical lifting device, Herschel was lifted from the CCU3 pallet and hoisted up inside the BAF airlock and into to the high bay of the BAF.

Inside the high bay stood the Ariane 5 ECA launcher with the Planck spacecraft and the SYLDA 5 support structure, which were mated already on top of the launcher on 23 and 27 April, respectively.

The SYLDA 5 (Système de Lancement Double Ariane 5) is a support structure that can be used during joint launches on an Ariane 5 launcher to carry the upper part of the launcher's payload, which in this case is the Herschel spacecraft. It consists of a load-bearing carbon structure that at its base is fixed to the launcher. With its high cylindrical shell and truncated conical shell at the top the SYLDA 5 encapsulates the lower part of the launcher's payload; in this case the Planck spacecraft.

The top of the SYLDA 5 is open through which the top 25 centimetres of the Planck spacecraft protrude. This part of the Planck spacecraft will be enclosed in the space just under the Herschel spacecraft, inside the about 0.33-m-high launcher adapter ring (ACU).



In the morning on 30 April an overhead crane manoeuvred the Herschel spacecraft over the SYLDA 5 support structure. The Herschel spacecraft was lowered into place after which the launcher adapter ring and the SYLDA 5 structure were bolted together and the flight torques were applied. The electrical connections between the ACU and SYLDA 5 were installed and verified, followed by a functional check of the Herschel spacecraft after its mating with the SYLDA 5 on the Ariane 5 ECA launcher.

The launcher carrying the two spacecraft (which is over 35 metres tall) is hidden from view by the two movable access platforms that surround the top of the launcher at the level just below the base of the SYLDA 5 and at the top of the SYLDA 5 or as convenient.