Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry

We describe the results of three separate sets of impact tests conducted during the development of the DS-2 Mars Microprobe mission. As well as indicating the promise of penetration to ∼0.5 m depth on Mars, these tests show the utility of accelerometer data in determining the penetration depth, the hardness of the surface material and the existence of layers, and the presence of coarse-grained material. Various lessons learned in instrumentation and operation, airgun testing and target characterization, and penetrator design for reliable separation, are discussed.