a compact micro-libs instrument for chandrayaan-2 mission: development and performance aspects of qualification model
- Paper number
IAC-18,A3,2B,3,x43128
- Author
Mr. A.S. Laxmiprasad, India, Laboratory for Electro-Optics Systems (LEOS)-ISRO
- Coauthor
Dr. M.V.H. RAO, India, Laboratory for Electro-Optics Systems (LEOS)-ISRO
- Coauthor
Mr. V.L.N. Sridhar Raja, India, Laboratory for Electro-Optics Systems (LEOS)-ISRO
- Coauthor
Mr. Adwaita Goswami, India, Laboratory for Electro-Optics Systems (LEOS)-ISRO
- Coauthor
Mr. K.A. Lohar, India, Laboratory for Electro-Optics Systems (LEOS)-ISRO
- Coauthor
Mrs. Monika Mahajan, India, Laboratory for Electro-Optics Systems (LEOS)-ISRO
- Year
2018
- Abstract
India's second moon mission, viz., Chandrayaan-2 to be launched in the year 2018 will place a lander along with a 6-wheeled rover at the lunar south pole region (in addition to an orbiter in ~100km orbit). The rover shall move around the landing area to enable science observations of the surface at a close distance. To meet the defined science objective of identification and abundance estimation of major, minor, trace and volatile (H, C, N, O, P, S, K and OH-) elemental content of lunar surface, a Laser Induced Breakdown Spectroscope (LIBS) instrument is being developed by LEOS. It shall be located below the rover’s deck to sample the surface from a distance of ~200 mm. The design and development aspects of Engineering Model (EM) version of the instrument were presented elsewhere. Further development and realization of LIBS-Qualification Model (LIBS-QM) has gone through a series of design corrections to overcome challenges faced during testing phase of EM in vacuum environment. The reconfigured LIBS-QM is a light-weighted ($<$ 1.2 Kg), low power consuming ($<$ 5 Watt) compact module that occupies a volume of just 180mm x 150mm x 80mm. LIBS-QM is equipped with a strong Mg-alloy structure that houses optical elements in titanium mounts. The optical modules of LIBS-QM can produce a power density of ~12 GW/c$m^2$ at the investigation site by focusing a 1.54 $\mu$m pulsed laser to a spot size of ~50 $\mu$m and are of capable to register the resulting plasma emission spectrum in the spectral range of 220nm-800nm with a resolution of $<$1nm. The light throughput of emission collection optics is improved considerably over EM by redesigning and with specialized coatings. Spectrograph module of LIBS-QM is realized through a combination of a single aberration- corrected concave holographic reflective grating element, a rectangular slit and a linear array CCD detector. LIBS-QM, which is designed for an operational temperature range of -2$0^0$C to +5$5^0$C, has successfully undergone space environmental qualification tests such as thermo-vacuum cycling test(temperature range of -4$0^0$ C to +7$0^0$ C) at vacuum levels of better than 5x1$0^-^6$ mbar and withstood vibration levels of up to 20g(RMS). Using this model, a LIBS spectral database using geo-chemical standard/certified reference samples and minerals is being generated to address qualitative and quantitative analysis prospects. Through this paper, authors shall discuss challenges faced during EM testing, LIBS-QM design improvisations, calibration aspects, space qualification test details, observations and results.
- Abstract document
- Manuscript document
(absent)