LISA proof mass, split & hollowed

A full-scale model, split in two and hollowed to accommodate insertion of denser material, of the proof mass used in LISA Pathfinder, a European Space Agency spacecraft launched on Dec. 3, 2015. Printing the model in this way reduces the price significantly over printing the full cube on Shapeways. The interior space allows insertion of a 1.5 x 1.1-inch weight (such as an extruded brass square cut to fit) to give the object a more realistic heft when handled. An appropriately sized brass piece weighs about 12.4 ounces, or less than one-fifth the weight of the real object. The halves can be joined using superglue or epoxy resin.

LISA Pathfinder will demontrate technology for observing ripples in the fabric of space-time called gravitational waves. The proof mass is allowed to follow a pure free-fall trajectory, which the spacecraft tracks. 

A model of the spacecraft for the proposed LISA mission is available here.