Possible Detection of Nitrates on Mars by the Sample Analysis at Mars (SAM) Instrument

摘要: Introduction: Planetary models suggest that nitrogen was abundant in the early Martian atmosphere as dinitrogen (N 2). However, it has been lost by sputtering and photochemical loss to space [1, 2], impact erosion [3], chemical oxidation nitrates [4]. Nitrates , produced Mars' history, are later decomposed back into N 2 current flux [5], making possible a cycle on Mars. It is estimated layer of about 3 m pure NaNO should be distributed globally Mars [5]. fundamental source for terrestrial microorganisms. Therefore, detection soil important assess habitability environment. The only previous mission designed search Phoenix but unable detect evolved N-containing species TEGA MECA WCL [6]. have tentatively identified Nakhla meteorite [7]. purpose this work determine if were detected first solid sample (Rocknest) Gale Crater examined SAM instrument. Materials Methods: Samples collected from Rocknest, located Crater, which consists an inactive, sandy wind drift mantled with dust, analyzed Prior analysis, blank run using empty quartz cup characterize background sealed inside pyrolysis oven heated ~840°C at rate 35°C/min under He carrier gas flow 1.5 cm /min pressure ~30 mbar. A small fraction released measured directly electron quadrupole mass spectrometry (QMS range 2-535 Da, resolution 0.1 Da). Then four samples Rocknest bedform materials < 150 μm diameter size (~20 mg) SAM. thermal analyzer (Netzsch STA 449 F1 Jupiter Simultaneous TG/DSC) coupled spectrometer QMS 403 C Aeolos) used laboratory heat upto 1200°C 20°C/min