Motivated by the rubbing saga of ETMX (15985), I have compiled a list of how much each stage of each suspension sags with temperature. This log is just like LLO 15636, except that instead of just top masses, all the stages are included here. The derivation of the temperature sensitivity is in LLO 12581.
Table 1: Vertical sag with temperature (microns / C)
| Stage | QUAD | BS | HLTS | HSTS | OMC | TMS |
| 1 (top mass) | -106 | -38 | -37 | -62 | -50 | -88 |
| 2 | -182 | -57 | -60 | -96 | -64 | -129 |
| 3 | -223 | -58 | -60 | -96 | -- | -- |
| 4 (test) | -224 | -- | -- | -- | -- | -- |
These numbers were calculated using the derivation in LLO log 12581. The formula from that log is
dz/dt = -254*m*g/K [microns / C]
where m is the total suspend mass of a given SUS stage [kg], K is the total vertical stiffness supporting that mass [N/m], and g is gravity [m/s^2]. The negative sign indicates a drop in height with increasing temperature. The thermal sensitivity of the young's modulus of maraging steel is given by "The maraging-steel blades of the Virgo super attenuator." Braccini et al, Meas Sci Tecnol 11 (2000).
Table 2: Relevant SUS parameters
| Spring properties | QUAD | BS | HLTS | HSTS | OMC | TMS |
| Stage 1 mass (kg) | 123.32 | 40.42 | 36.46 | 8.99 | 10.02 | 123.94 |
| Stage 1 stiffness (N/m) | 2889 | 2684 | 2437 | 360 | 500 | 3519 |
| Stage 2 mass (kg) | 101.32 | 27.79 | 24.37 | 5.87 | 7.12 | 79.86 |
| Stage 2 stiffness (N/m) | 3333 | 3540 | 2689 | 439 | 1229 | 4847 |
| Stage 3 mass (kg) | 79.32 | 14.21 | 12.14 | 2.89 | -- | -- |
| Stage 3 stiffness (N/m) | 4875 | 83213 | 189190 | 43139 | -- | -- |
| Stage 4 mass (kg) | 39.64 | -- | -- | -- | -- | -- |
| Stage 4 stiffness (N/m) | 72139 | -- | -- | -- | -- | -- |
| Parameter file | quadopt_fiber | bsfmopt_glass | hltsopt_metal | hstsopt_metal | omcsopt_metal | tmtsopt_production |