Following the acoustic tests which took place at ESTEC in September, the LISA Pathfinder modules were returned to a clean room in anticipation of the shock tests which were scheduled for late October. These tests are devised to measure the shock level the equipment will receive as a result of the firing of the pyrotechnic devices and subsequent opening of coupling clamps. Measurements are made to determine if the shock levels that propagate through the spacecraft remain below the levels that have been specified, at the beginning of the programme, for the various spacecraft constituents. Two separate shock tests were performed. The first test, which took place on October 23rd, measured the shock levels arising as a result of the separation of the science and propulsion module. When launched, the science and propulsion modules are held together with a clamp band until they reach the operational orbit. At L1 the clamp is opened by firing two pyrotechnic devices and the modules separate so the LISA Pathfinder science module can continue with drag-free operations. As LISA Pathfinder houses a very delicate payload (the LISA Technology Package), the clamp that is used to couple the modules is a model which imparts a particularly low shock.
The second test, on October 31st, measured the shock imparted when the launch vehicle adapter separates from the spacecraft. For this test, an exact replica of the adapter for the Rockot launcher, the backup launch vehicle for LISA Pathfinder, was used. These tests were performed with the support of personnel from EUROCKOT, KHRUNICHEV and CASA. A similar test will be repeated at a later date for the Vega launcher — the baseline launch vehicle for LISA Pathfinder.
