and used the sophisticated apparatus shown in the attachment to test marionette suspension in standalone.
Obviously, we had to rearrange the mass distribution, as the bending point, without the reaction mass and the mirror loads goes a bit above the marionette CoM. Hence balancing is not straightforward as the system was "softer" (f_pitch and roll ~ 89 mHz, consistent with standard bending point simplified formula). Indeed, the overall balance that matters is that done inside the tower with the correct load on the wire.
Anyhow, the test was useful for two reasons:
1) we confirmed that as long as the nominal motor counterweights are adopted, also using the original motors (instead of the "dummy motors used during preliminary test in lab, entry 49841) the marionette is unbalanced on the same side.
We reduced the mass of the counterweights by 50% and balanced. Tomorrow the counterweights actually installed into the old marionette will be checked. Anyway the difference in counterweight load, if really needed, will be compensated by adding ballast on the marionette.
2) Also, we checked that the new short maraging wire clamped at the marionette CoM behaves correctly.
Concerning point 1) of the entry, yesterday we checked the actual counterweights of the motors hosted in the old marionette and they turned out roughly 1/3 lighter than those designed for the new marionette upon nominal drawings.
Then the new IMC crew (Basti et al.) installed these lighter counterweights and balanced at the best the marionette in lab 1500 West before suspending the marionette to SA of IMC. The installation is being performedd in two steps, as done in the past in this particular case. Today the bottom part of the payload.