We propose here the application of Micro-Electro-Mechanical Systems (MEMS) as part of a science surface properties package aboard a future Lake Lander. MEMS devices offer a low cost and reduced size of instrumentation in order to accomplish the 3-D sounding of the liquid deposit and detect the presence of any biomarkers in a broader area.This deployment will provide a broad network of surface and submarine IR and RF sources, while the signal receiver sensor will be aboard the Lake Lander. The MEMS micro-probes will follow the swarm pattern in which each apparatus single operation is a component of a large group of similar devices.
Each MEMS device will include a combination of scientific instruments in micro scale. In particular, one pair of infrared (IR) and radio frequency (RF) emitters and two sensors for measuring the temperature and the pressure will be enclosed in each micro-shell. Additionally, MEMS technology can be part of the IR spectrometer's equipment aboard the LakeLander.
Apart from traditional IR sources, micro-machined infrared emitters have been constructed, comprised of a photonic crystal modified micro-hotplate that emits thermally stimulated infrared radiation in a narrow band. As far as the performance of the device is concerned, it exhibits efficiencies in excess of 10 % greater than competitive technologies. These applications are like the deposited filament emitter, with the advantage of minimization of the filament which reduces the thermal mass of the system and enhances the modulated performance.
MEMS technology can be implemented at the IR spectrometer's architecture of a classical Michelson interferometer, being a transducer of the IR sensor. MEMS translational mirrors, covering an area of 1.1x1.5 mm2 have been already tested giving reliable measurements at high scanning speed -in milliseconds- which enhances signal-to-noise ratio, suspended on a two long bending springs pattern. A recent approach is the pantograph, which even though it exhibits less stability, it covers a surface mirror of 7 mm2 providing a spectral resolution of 20 cm-1. The IR source can be based on silicon structure, a pattern which is already in long-term use for detecting gas in oil platforms without a failure recording. In Titan's case, the target gases are mainly hydrocarbons, nitriles and carbon dioxide.
The cold environment of Titan can cause serious damage at the mirrors such as deformation and flaking. To achieve robust function in this harsh temperature conditions these micro-mirrors can be based on a silicon-on-insulator wafer, while their back surface can be made of polycrystalline silicon.
If the liquid material behaves as a partial conductor (when consisting of i.e. ionic contaminants), it will prevent RF propagation in long distances. Such liquid conductors set the independent operation of these RF emitters inside the liquid under discussion, since their high permitivity and permeability cause strong attenuation of the signal power. For this reason the capsules which will be designed to dive in the lake can be connected by a wire with the mother ship as it shown. This pattern can also support the micro probes with energy originated by the carrier.