This letter describes an implementation of micromachined seismometer based on molecular electronic transducer (MET) technology. As opposed to a solid inertial mass, MET seismometer senses the movement of liquid electrolyte relative to fixed electrodes. The employment of micro-electro-mechanical systems techniques reduces the internal size of the sensing cell to 1 lm and improves the reproducibility of the device. For operating bias of 600 mV, a sensitivity of 809 V=ðm=s 2 Þ was measured under acceleration of 400 lgðg 9:81 m=s 2 Þ at 0.32 Hz. A À115 dB (relative to ðm=s 2 Þ= ffiffiffiffiffi ffi Hz p) noise level at 1 Hz was achieved. This work develops an alternative paradigm of seismic sensing device with small size, high sensitivity, low noise floor, high shock tolerance, and independence of installation angle, which is promising for next generation seismometers for planetary exploration. V

Molecular Electronic Transducer (MET) is a recent technology applied in seismic instrumentation that proves highly beneficial to planetary seismology. MET is an electrochemical cell that senses the movement of liquid electrolyte between electrodes by converting it to the output current. Seismometers based on MET technology are attractive for planetary applications due to their high sensitivity, low noise floor, small size, lack of fragile moving parts and independence on the direction of sensitivity axis. This paper reports an approach to build a micro MET seismometer using Micro-Electro-Mechanical Systems (MEMS) techniques. We have reduced the MET cell size, resulting in internal dimensions close to 1 micrometer (µm). The employment of MEMS improves the sensitivity up to and reproducibility of the device, and has reached 1 micro Gee ( √ ) noise level at 1 Hz.

The 2013 Planetary Science Decadal Survey identified a detailed investigation of the Trojan asteroids occupying Jupiter's L4 and L5 Lagrange points as a priority for future NASA missions. Observing these asteroids and measuring their physical characteristics and composition would aid in identification of their source and provide answers about their likely impact history and evolution, thus yielding information about the makeup and dynamics of the early Solar System. We present a conceptual design for a mission to the Jovian Trojan asteroids: the Trojan ASteroid Tour, Exploration, and Rendezvous (TASTER) mission, that is consistent with the NASA New Frontiers candidate mission recommended by the Decadal Survey and the final result of the 2011 NASA-JPL Planetary Science Summer School. Our proposed mission includes visits to two Trojans in the L4 population: a 500 km altitude fly-by of 1999 XS143, followed by a rendezvous with and detailed observations of 911 Agamemnon at orbital altitudes of 1000 -100 km over a 12 month nominal science data capture period. Our proposed instrument payloadwide-and narrow-angle cameras, a visual and infrared mapping spectrometer, and a neutron/gamma ray spectrometer -would provide unprecedented high-resolution, regional-toglobal datasets for the target bodies, yielding fundamental information about the early history and evolution of the Solar System. Although our mission design was completed as part of an academic exercise, this study serves as a useful starting point for future Trojan mission design studies. In particular, we identify and discuss key issues that can make large differences in the complex trade-offs required when designing a mission to the Trojan asteroids.