We went in the EY chamber and saw that the return beam was off on the secondary mirror at 1:30 position, the radial distance from the forward going beam was maybe 5 or 6mm. The return beam was not even hitting the bottom periscope mirror under the TMS optics table.

We steered TMS suspension as much as we could using the bias slider and it was clear that we need at least twice the range for YAW, more for PIT. We need positive PIT and YAW, both at around a milliradian. That's huge misalignment.

This cannot be ring ERM as the original ERM was wedge-less.

The wedge of the new ETM is somewhat different (old one was 0.076 deg, new one 0.07, the difference is 0.006 deg or 100 urad), and this is not large enough to cause milliradian difference.

We checked apparent interference but we couldn't do a thorough job.

We installed kapton washers to the picos, but we haven't installed collars as it will change the TMS balance (we will NOT fix the lack of collars as there's no need for gross motion of picos at this point).