MRV Communications (United States)

The feasibility of extended exploration and human presence on the Moon and Mars depends critically on dealing with various environmental factors, and especially on the effects of dust. One of the most restricting facets of lunar surface exploration, as experienced by the prior Apollo landed missions, is the fine lunar dust, its high adherence, and its restrictive friction-like action. Moreover, the lunar dust particle size distribution extends generally into the submicron range, where it could potentially have toxic effects on exposed astronauts through their respiratory system. MoonDust is a project being performed in collaboration with the Canadian Space Agency to study the effects of lunar dust on optics and mechanical elements, and to develop innovative nano-filtration solutions to extend their operational lifetime within a lunar and/or Mars environment. To assist this work, a small lunar environment simulation vacuum chamber is being developed at MPBC, to enable the study of lunar dust effects on optics elements and rotary mechanisms, at pressures brought down below 10 -5 Torr. The developed simulator includes an injection system for lunar dust simulants, an excimer UV laser-light source for vacuum UV (VUV), and various diagnostic ports for relevant optical and electrical measurements. The MoonDust innovative dust mitigation solution exploits key characteristics of the lunar dust while incorporating nano-filtration technologies based on carbon nanotubes (CNT) materials. The aim is to minimize the required consumables while providing high capacity and high efficiencies for the more dangerous submicron particles. This paper reports on the development of the lunar environmental chamber and the associated lunar dust simulator. Some of the preliminary trial experimental results for filters based on CNTs for optical devices and rotary mechanical joint protection are also presented.

<div class="htmlview paragraph">Infrared (IR) spectroscopy probes the characteristic vibrational and rotational modes of chemical bonds in molecules to provide direct information about both the chemical composition and the bonding configuration of a sample. The significant advantage of the IR spectral technique is that it can be used with minimal consumables to simultaneously detect a large variety of different chemical and biochemical species with high chemical specificity. Currently, various VIS/NIR grating spectrometers are employed to cover the spectral range between 0.3 and about 2.2 (μm. Bulk-optic Fourier Transform (FT)-IR spectrometers employing variations of the Michelson interferometer are generally used to provide spectral measurements above 2.5 (μm. The FT-IR systems tend to be mechanically complex, bulky (>15 kg), and require considerable processing, maintenance and recalibration.</div> <div class="htmlview paragraph">For space-based systems, the important drivers are reliability, power consumption, mass and simplicity of operation. MPBT has advanced its patent-pending IOSPEC<sup>™</sup> technology for miniature integrated IR spectrometers to provide high performance comparable to large laboratory spectrometers but in a very compact and ruggedized footprint weighing under 2.0 kg. It also bridges the gap between current VIS/NIR and FT-IR spectrometers by providing continuous coverage in the important 1 to 5 (μm spectral range at a relatively high nominal resolution of about 4 to 8 nm. The throughput limitation of single-slit diffractive spectrometers are overcome by replacing the traditional input slit with a programmable array of 16 slits to multiplex the input optical signal.</div> <div class="htmlview paragraph">This paper discusses recent advances in the binary-coded IOSPEC technology towards providing an integrated chemical analysis system for manned space systems and planetary rovers. An active shutter array is being developed based on a thin-film structure that enables broad-band optical switching and multiplexing at ms speeds with no moving parts for reliable long-term operation. Voltage-controlled optical switching has been obtained at 30 to 40 V. The efficiency of optical coupling to linear detector arrays is also being substantially improved using an integrated-optic condenser at the output of the guided-wave spectrometer to minimize the required height of the detector pixels relative to the height of the system input aperture. A novel, low-power MIR light source is also being developed to facilitate the spectral analysis of solid and liquid samples.</div> <div class="htmlview paragraph">A monolithically-integrated suite of miniature instruments is currently being developed for the Canadian Space Agency based on the IOSPEC<sup>™</sup> technologies to enable laboratory-quality remote chemical and biochemical analysis for future planetary explorers, as well as the analysis of liquids and solids for potential biohazards.</div>

Free-Space Optics (FSO) is a proven, reliable technology for last mile telecommunications applications, used worldwide for both enterprise network building-to-building connections and for wireless access to more traditional land line communications networks. In most mid-latitude coastal cities, link availability at distances above a few hundred meters is primarily affected by fog and low clouds. At longer distances, heavy rain and snow can also affect the link. The most mature technology used in FSO equipment relies on low cost semiconductor lasers or LED’s operating in the near infrared at wavelengths of 785 nm or 850 nm. In the past few years, systems operating at 1550 nm have also been developed. At first the vendors of these systems claimed that the 1550 nm wavelength had better propagation characteristics in severe weather than the 785 nm wavelength. With further analysis and research, those claims were withdrawn. Now there are claims that even longer wavelengths near 10 microns will solve the FSO link availability issues associated with severe weather. Hype about such magic wavelengths for FSO is both a disservice to the investors who will lose the money they are investing based on exaggerated claims, and to the rest of the FSO industry which should be creating realistic expectations for the capability of its equipment. In the weather conditions which normally cause the highest attenuation for FSO systems, namely coastal fog and low clouds, 10 microns offers no propagation advantage over shorter wavelengths.