244 Lessons   When using large intentional operational dynamic environments in a sampling system, anticipate the  need for isolation to protect sensitive instruments located near the dynamic sources. Address the need  early on in the subsystem configuration studies by either using di screte isolator assemblies (as in  SA/SPaH) or by physically separat ing these instruments from the dynamic sources in the overall  configuration.   The wire rope isolator proved to be an effective so lution for our space-constrained Turret but at the  expense of lots of development test time.

Testing   For many elements of the SA/SPaH design, testing began with development  testing on specific functions  of sampling to determine and appropriately size the basic elements of the subsystem and the devices  within the subsystem. These tests informed our har dware design choices and were used extensively in  the areas where new designs were developed such as the Drill, CHIMRA, DRT, In strument Isolators, and  Bit Box. Development testing was the start of our process of risk reduction and subsystem  characterization.  All SA/SPaH hardware elements have both an Engineeri ng Model (EM) and a Flight Model (FM). EM  units are flight-like but generally see a reduced te st program (no random vibe and limited or no thermal  testing) prior to delivery to a system testbed. EM  tests for the Drill, CHIMRA, and Arm are targeted at  understanding the mechanism performance. In the testbed, this hardware is eventually assembled into a Rover-based SA/SPaH subsystem and operated with flight -like electronics and flight software in an Earth  ambient environment, including operations on rocks and r egolith. In a few instances (DRT, Instrument  Inlet Covers, and Instrument Contact Sensors), EM uni ts see a full test program and serve as Life Test  Units prior to testbed delivery. FM units see a full test program designed to prove acceptance for flight.   In addition to the EM and FM units, the Drill, CHIMRA, and Instrument Isolators al so have a Qualification  Model (QM). QM units are used for mechanism life test s, structural verification, sampling verification and  validation (operating on Mars analog rocks and regolith in a low-pressure Mars environment over the temperature range), validation of the contamination control processes, and thermal characterization.   The Drill and CHIMRA in the integrated Turret configurat ion form a critical portion of the MSL sample  chain from acquisition of material until deposition into the analytical instruments. In addition to the typical  flight hardware qualification test program, two additional types of testing form an essential part of the test  program. The first is the dynamic characterization of the Turret hardware to its self-induced operational  dynamic environments of CHIMRA vibr ation and Drill percussion. The second is the testing of the sample  acquisition and processing hardware functions using Mars analog materials in a low-pressure Mars  environment over the required temperature range.  The flight-like EM Turret, consisting of the EM Drill, CHIMRA, Instrument Isol ators, mounting brackets,  and mass models in place of the DRT, APXS, and MAHLI, was assembled on the EM Arm (Figure 10). The Turret and Arm were heavily instrumented with a ccelerometers to measure the response to CHIMRA  vibration and Drill percussion in various Arm poses re levant to the SA/SPaH functions. Locations include  the soft side of the MAHLI and APXS Isolators, near eac h CHIMRA sieve, the Sample Transfer Tube, the  Drill aft housing, and some of the Arm joints (a total of 10 3-axis accelerometers).   The purpose of Turret dynamic characterization testi ng is to determine the response to CHIMRA vibration  and Drill percussion at critical locations on the Turret, to find the frequency of the CHIMRA mode,  therefore determining the operating speed of CHIMRA vibe, to select the value of the eccentric mass that  produces 4-10 G on the primary sieve, and to confirm that the Isolator requirements are met in the  presence of the Drill and CHIMRA operational dynamic environments. Figure 11 shows two of the many poses characterized in the testing. The primary siev e pose is a particularly important one since it sizes  NASA/CP-2010-216272