Herschel Telescope Flight Model at ESTEC
01 February 2008 10:34
The Herschel telescope's primary mirror is the largest mirror ever built for space. It is made out of 12 silicon carbide (SiC) petals brazed together and coated with a thin aluminium reflective layer. The SiC provides a rigid but lightweight structure with the telescope mass totalling at about 320 kg.
In the morning on Friday 18 January, the flight model of the 3.5-metre diameter telescope arrived at ESTEC in Noordwijk on its transporter truck. Upon arrival the outside of the telescope container was first cleaned before the transport was turned to cleanroom loading bay-airlock #3 for unloading of the container holding the large telescope.
On 24 January, the unpacking of the telescope was performed in the cleanroom, starting with the lifting of the transport container cover. The images below show the telescope – still with a white protective cover – being hoisted from its transport stand onto its ground handling system.
Tuesday, 29 January, the telescope was successfully cleaned after removal of its protective white cover, with ETS and ISS cleaning services providing material support.
Next, the detailed inspection of the telescope's condition after transport was started - the incoming inspection - with ESA and the product assurance team from Astrium France: ASEF PA. The inspection of the secondary mirror M2 and its support structure (barrel and hexapod legs) was completed the same day without problems.
Cleaning and inspection of the large telescope, 29 January
Inspection continued 30 January for the primary mirror M1 with participation of the product assurance team from Astrium Germany (ASED PA). The telescope was secured overnight with its optical axis horizontal in the locked cleanroom.
The next major milestones for the telescope will be a fit-check of the telescope's interface with the spacecraft on a reference plate (simulating the actual spacecraft interface) and the M1/M2 distance measurement of the telescope's primary and secondary mirror. Eventually the telescope will be integrated on top of the Herschel cryostat vacuum vessel that is currently set up for its cooldown and filling of the cooling system with liquid helium.
Last Update: 08 February 2008