Measurement of the momentum transferred between contacting bodies during the LISA Test Mass release phase - uncertainty estimation

The requirements for the Laser Interferometer Space Antenna (LISA) test-mass (TM) release phase are analysed in view of the building up of a testing facility aimed at on-Earth qualification of the release mechanism. Accordingly, the release of the TM to free-fall must provide a linear momentum transferred to the TM not exceeding 10-5 kg m s-1. In order to test this requirement, a double pendulum system has been developed. The mock-ups of the TM and the release-dedicated plunger are brought into contact and then the latter is quickly retracted. During and after release, the TM motion is measured by a laser interferometer. The transferred momentum is estimated from the free oscillations following the plunger retraction by means of a Wiener-Kolmogorov optimal filter. This work is aimed at modelling the measurement chain, taking into account procedure, instruments, mechanisms and data elaboration in order to estimate the uncertainty associated with the transferred momentum measurement by means of Monte Carlo simulation. © 2009 IOP Publishing Ltd.