Evidence offeasible hardness test on Mars using ratio of ionic - neutral emission intensities measured with laser-induced breakdown spectroscopy in lowpressure CO2 ambient gas

An experimentalstudyisconductedonthepossibilityandviabilityofperforminghardness measurement ofthevariousstoneandchertsamplesinlowpressure(600Pa)CO2 ambient gas,a condition thatisencounteredintheMarsatmosphere.Forthisstudy,ananosecondNd-YAGlaser is employedtogenerateplasmaemissionfromthesampleswithdifferentdegreesofhardness.This technique isdevelopedinlightoftheroleoftheshockwaveinthegenerationofalaser-induced plasma. Itwaspreviouslyshownthatthespeedoftheshockfrontdependsonthehardnessofthe sample, andapositiverelationshipwasfoundbetweenthespeedoftheshockfrontandtheioniza- tion rateoftheablatedatoms.Hence,theratiooftheintensitybetweentheMgII279.5nmandMg I 285.2nmemissionlinesdetectedfromthelaser-inducedplasmacanbeusedtoestimatethehard- ness ofamaterial.Infact,itisshownthattheratiochangeslinearlywithrespecttochangesofsam- ple hardness.TheresulthasthusdemonstratedthefeasibilityandviabilityofusingLIBSfornon contact hardnessmeasurementonMars.