1. LBT Q3 2007 Engineering Review Primary Mirror Cells

2. 26-Oct-2007LBT Q3 2007 Engineering Review Highlights (Q3/2007) Cells still behaving very well Cells still behaving very well HP duals eliminated HP duals eliminated Speed y-axis of the SX mirror cell has decreased (recognized by unexpected oscillation) Speed y-axis of the SX mirror cell has decreased (recognized by unexpected oscillation) Actuators reliable, 1 failure in first year Actuators reliable, 1 failure in first year Punch list completed, mirrors and cells belong to LBT Punch list completed, mirrors and cells belong to LBT Acid leak in DX cell Acid leak in DX cell

3. 26-Oct-2007LBT Q3 2007 Engineering Review Open Issues Technical Technical Cell Documentation deficient and/or nonexistent Cell Documentation deficient and/or nonexistent Hardpoints have lower stiffness that desired, meet 80N/ m (min required) Hardpoints have lower stiffness that desired, meet 80N/ m (min required) Air boxes hot, require insulation/ventilation Air boxes hot, require insulation/ventilation Actuator test stand undocumented/not maintainable Actuator test stand undocumented/not maintainable Dew-point of cell compressed air not being monitored Dew-point of cell compressed air not being monitored Presence of high concentrations of chlorine through mirror cells point to mirror cleaning solutions as the probable source/cause of corrosion products removed from the cells and air ejector. Presence of high concentrations of chlorine through mirror cells point to mirror cleaning solutions as the probable source/cause of corrosion products removed from the cells and air ejector. Schedule Schedule None None Financial Financial Cell documentation proposal approved Cell documentation proposal approved ETS Test Stand proposal will be cost-plus, >$140k ETS Test Stand proposal will be cost-plus, >$140k Resource Resource Mountain staff limitations pace work at Observatory Mountain staff limitations pace work at Observatory ETS staff limitations pace cell documentation effort ETS staff limitations pace cell documentation effort

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15. 26-Oct-2007LBT Q3 2007 Engineering Review Progress (Q3/2007) Cell punch completed Cell punch completed MirrorLab contract closed MirrorLab contract closed HP duals eliminated HP duals eliminated DX raised following aluminizing DX raised following aluminizing

16. 26-Oct-2007LBT Q3 2007 Engineering Review Planning (Q4/2007) Dew-point monitors will be ordered/installed. Dew-point monitors will be ordered/installed. ETS to modify hardpoint monitor board (TBD) ETS to modify hardpoint monitor board (TBD) ETS will rework Actuator Calibration Stand (TBD) ETS will rework Actuator Calibration Stand (TBD) Engineering will complete DX characterization measurements 4 th qtr Engineering will complete DX characterization measurements 4 th qtr