In this paper, we report on the on-going development of a compact analytical instrument for future missions to the Moon, using the LIBS technique. The instrument, christened VOILA (Volatiles Identification by Laser Ablation), is part of the “LUVMI-X” scenario funded by the European Union’s Horizon 2020 programme which envisions the concept of a rover carrying a suite of instruments for detecting and characterizing volatiles as a component of lunar soil (“regolith”) at high latitudes on the Moon. Behaviour of the plasma created by LIBS target ablation depends on the prevalent atmospheric pressure. Mars atmospheric pressure is close to ideal for the LIBS technique. On bodies without atmosphere such as the Moon, the lack of confining pressure leads to the plasma dissipating quickly causing weaker signals. India has developed the first, modest LIBS instrument for operation on the Moon with however a number of limitations in its optical design. Moreover, the lander of the corresponding mission Chandrayaan-2 crashed during landing in 2019. Our VOILA is designed to be between the quite capable but large and massive Mars LIBS instruments of NASA (ChemCam on the CURIOSITY ANCE rover), and the very modest Indian LIBS for Chandrayaan- 2. The VOILA working range will vary between 0.3 and 0.5 m, with a laser pulse energy of ~15 mJ.
Modern telecommunication satellites can benefit from the features of fiber optic sensing wrt to mass savings, improved performance and lower costs. Within the course of a technology study, launched by the European Space Agency, a fiber optic sensing system has been designed and is to be tested on representative mockups of satellite sectors and environment.
Scientific experiments on mineral and biological samples with Raman excitation below 300nm show a wealth of scientific information. The fluorescence, which typically decreases signal quality in the visual or near infrared wavelength regime can be avoided with deep ultraviolet excitation. This wavelength regime is therefore regarded as highly attractive for a compact high performance Raman spectrometer for in-situ planetary research. Main objective of the MIRAS II breadboard activity presented here (MIRAS: Mineral Investigation with Raman Spectroscopy) is to evaluate, design and build a compact fiber coupled deep-UV Raman system breadboard. Additionally, the Raman system is combined with an innovative scanning microscope system to allow effective auto-focusing and autonomous orientation on the sample surface for high precise positioning or high resolution Raman mapping.
Modern telecommunication satellites can benefit from the features of fiber optic sensing wrt to mass savings, improved performance and lower costs. Within the course of a technology study, launched by the European Space Agency, a fiber optic sensing system has been designed and is to be tested on representative mockups of satellite sectors and environment.
The optical part of the Raman Laser Spectrometer (RLS) instrument for ExoMars consists of an excitation laser, an optical harness, an optical head and a spectrometre. The optical harness delivers the green radiation generated by the laser to the optical head which, in turn, focuses the laser radiation on the sample of interest and collects the Raman emission from the sample. The optical head then separates excitation light and Raman emission by a filter setup and sends the isolated Raman signal to a reception fiber, which delivers it to the spectrometer of the instrument. This paper concentrates on the innovative technologies applied for the excitation path of the instrument, the laser, the optical harness with its new compact fiber optic connectors and the Raman optical head; and describes their design, the design driving requirements and the status these units have reached by now. The spectrometer of the system with its transmission grating design will be presented separately.
The Environmental Mapping and Analysis Program (EnMAP) is a German hyperspectral mission with pushbroom type imaging spectrometers covering the wavelength ranges from 420 nm to 2450 nm. The ground sampling distance is 30 m with a total swath of 30 km, while the spectral sampling distance is roughly 5 nm to 12 nm.
The Environmental Mapping and Analysis Program (EnMAP) is a German hyperspectral satellite mission that aims at monitoring and characterizing the Earth’s environment.
Many different environmental factors can have an effect on optical coating durability for space applications. This includes in-orbit effects such as vacuum exposure, UV radiation, particle radiation, atomic oxygen, thermal cycling, contamination and orbital debris, as well as ground based effects such as cleaning, contamination and humidity [1].
The optical system of the hyperspectral imager of the Environmental Mapping and Analysis Program (EnMAP) consists of a three-mirror anastigmat (TMA) and two independent spectrometers working in the VNIR and SWIR spectral range, respectively. The VNIR spectrometer includes a spherical NiP coated Al6061 mirror that has been ultra-precisely diamond turned and finally coated with protected silver as well as four curved fused silica (FS) and flint glass (SF6) prisms, respectively, each with broadband antireflection (AR) coating, while the backs of the two outer prisms are coated with a high-reflective coating. For AR coating, plasma ion assisted deposition (PIAD) has been used; the high-reflective enhanced Ag-coating on the backside has been deposited by magnetron sputtering. The SWIR spectrometer contains four plane and spherical gold-coated mirrors, respectively, and two curved FS prisms with a broadband antireflection coating. Details about the ultra-precise manufacturing of metal mirrors and prisms as well as their coating are presented in this work.
Optical instruments for remote sensing applications frequently require measures for reducing the amount of external,
unwanted stray light in the optical instrument path. The reflective planet baffle design and manufacturing process for the
thermal infrared imaging spectrometer MERTIS onboard of ESA's cornerstone mission BepiColombo to Mercury is
presented. The baffle has to reflect the unwanted solar flux and scattered IR radiation, and minimize the heat load on the
instrument.
Based on optical stray light simulations and analyses of different baffle concepts the Stavroudis principle showed the
best performance and the smallest number of internal reflections. The setup makes use of the optical properties of
specific conic sections of revolution. These are the oblate spheroid, generated by rotating an ellipse about its minor axis,
and the hyperboloid of one sheet, obtained by the rotation of a hyperbola around its conjugate axis.
Due to the demanding requirements regarding surface quality, low mass and high mechanical stability, electroforming
fabrication was selected for the baffle. During manufacturing, a layer of high strength nickel alloy is electrodeposited
onto a diamond turned aluminum mandrel. The mandrel is subsequently chemically dissolved. Not only the baffle, but
also the baffle support structure and other mating components are electroformed. Finally, the baffle and support structure
are assembled and joined by an inert gas soldering process. After the optimum baffle geometry and surface roughness
has been realized, the remaining total heat flux on the baffle is only dependent on the selection of the appropriate, high
reflective coating.
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