Europa clipper instrument accommodation in the proposal phase

The proposed Europa Clipper mission would send a suite of instruments to Jupiter´s Europa moon. The scope of these instruments objectives would range from gravity science, high resolution imaging of the icy surface, thermal and topographical imaging/mapping; to plasma science, neutral mass spectrometry and infrared spectroscopy, and perhaps most importantly ice penetrating radar capability used for examining the potential liquid water ocean beneath the icy outer shell. Perhaps the largest test is solving these challenges in the proposal phase of the mission. In the pre-project timeframe, and nearly a year from instrument selection, broad assumptions must be made and used to drive the system design and implementation. Considerations include: optical fields of view of instruments (both direct and stray light), instrument thermal radiative fields of view (to other structures and to space), co-bore-sight requirements between instruments, and instrument stability over the life of the mission. Many of these items are addressed with the implementation of a dedicated instrument mounting platform, kinematically mounted to the avionics module of the spacecraft. This approach helps deal with the above considerations by placing the instruments outside the spacecraft avionics module in the Nadir direction. This allows for greater control of field of view obstructions (both optical and thermal) by moving instruments away from other structures. It also gives greater stability to instruments with coupled optical alignment requirements (i.e. the Short Wave Infrared Spectrometer and the High Resolution Reconnaissance Camera). Kinematic mounting also ensures that moments are not introduced into the mounting plate structure due to thermal gradients.