The European Extremely Large Telescope (E-ELT), is a revolutionary new ground-based telescope concept with a 42 metres primary mirror.

The adaptive optics is mainly based on two corrective surfaces, a tilting mirror (M5) and a high-order adaptive mirror (M4).

In late 2007 ESO has granted two competitive Preliminary Design Studies of the M4 adaptive unit, one of the most critical and complex parts of the telescope. One contract has been assigned to Microgate (acting as Prime Contractor) in team with ADS, SAFRAN/SAGEM and INAF.

The adaptive unit is a 2.5 x 2.6m elliptic mirror controlled by 6306 contactless actuators.

Our design exploits the concept adopted in all previous units, but several implementation details were changed to deal with the challenges imposed by the size of the M4 unit.

In particular we adopted a modular concept that allows easy interfacing and system maintainability.

The baseline concept adopt a segmented thin shell made of six identical petals.

Microgate tasks:

• Prime contractor, control system design, electronic design, electronic manufacturing and test of Demonstration Prototype

Partner tasks:

• ADS – subcontractor Mechanical design, manufacturing of Demonstration Prototype
• SAGEM-Reosc – subcontractor Optical design and manufacturing (Demonstration Prototype Shell + Thin shell prototype)
• INAF-OAB – subcontractor Optical testing
• Politecnico di Milano, Dipartimento di Ingegneria Aerospaziale - Simulation

Rendering by ADS International