THE LIBS INSTRUMENT FOR CHANDRAYAAN-2 ROVER: ENGINEERING MODEL DEVELOPMENT ASPECTS
- Paper number
IAC-16,A3,2B,8,x34004
- Coauthor
Mr. A.S. Laxmiprasad, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Coauthor
Mr. Adwaita Goswami, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Coauthor
Mr. V.L.N. Sridhar Raja, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Coauthor
Mr. K.A. Lohar, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Coauthor
Dr. M.V.H. RAO, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Coauthor
Mrs. Monika Mahajan, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Coauthor
Mr. BIJOY RAHA, Laboratory for Electro-Optics Systems (LEOS)-ISRO, India
- Year
2016
- Abstract
Rapid and reliable analyzing capability for simultaneous multi-element determination of matter in any of its diverse forms, namely, solid, liquid or gas using an intense nanosecond pulse duration of laser beam makes laser induced breakdown spectroscopy (LIBS) a potential tool for planetary surface exploration via both in-situ and stand-off measurements. India's second moon mission i.e., Chadrayaan-2 in addition to the orbiter spacecraft will carry a lander that is housed with a 6 wheel rover in order to investigate the lunar surface at a close proximity in the vicinity of roving area. One of the two selected rover scientific instruments, named, LIBS (Laser Induced Breakdown Spectroscope) is currently under development at LEOS for multi-element composition analysis of lunar regolith from an in-situ distance of 200mm from the surface. The conceptualization, design and development aspects of proto-LIBS were presented elsewhere. Nevertheless, design and development aspects of Engineering Model LIBS ( EM-LIBS ) instrument are gone through a series of iterations to overcome issues those had faced during the development phases of proto-LIBS. The tailored EM-LIBS comprises a Yb:Er:Phosphate glass laser operating at 1534nm wavelength with pulse energy of 2-3mJ. A multi-lens element Focusing-Optics-Unit (FOU) to generate the laser plasma on the target surface at the targeted in-situ distance with the ability to overcome the surface undulations ( within +/-20\% of the 200mm ) is being developed. The plasma emission emanating from the target surface is collected by a chromatic aberration corrected Collection-Optics-Unit (COU) and spectra are acquired using an aberration corrected concave holographic grating and linear-CCD based spectrograph. The spectrograph supports variable time delay in range of 1$\mu$s to 5$\mu$s and integration time of 8$\mu$s to 1ms. Suiting the mission constrains such as weight, size, power and available target distance beneath the rover; the instrument is realized with the weight of 1.2kg, power consumption of $<$5W and a footprint of 180mm x 150mm x 80mm. Algorithm towards the accomplishment of reliable qualitative is realized; while the algorithm of precise quantitative analysis is based on Calibrated-Free LIBS (CF-LIBS) methodology. Elemental abundance estimations are currently in progress on the acquired spectra resulted from various standard/reference samples including lunar regolith simulant (JSC-1A). Through this paper, authors shall discuss challenges faced in proto-LIBS realization, EM-LIBS design improvisations, modes of operations and calibration aspects of in-house developed spectrograph along with preliminary performance test results.
- Abstract document
- Manuscript document
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