ESA Science & Technology - Electrode housing and proof masses

At the core of the LISA Pathfinder spacecraft resides the LISA Technology Package (LTP) which is designed to demonstrate the technology needed for the LISA mission. The LTP is composed of two vacuum containers connected by an optical bench. Each vacuum container contains a proof mass enclosed in an electrodes housing box.

The electrode housing is pictured above with a set of four proof masses. The two on the left-hand side are the LISA Pathfinder flight proof masses, before being accurately machined and polished, while the other two are non-flight models used for testing.