Liu Wang, Wu Zhongchen, Chen Wenxi, Jin Guobin, Zhang Wei, Lv Xinfang, Yu Pei, Zhao Hong
School of Space Science and Physics, Institute of Space Sciences, Shandong University, Weihai, Shandong, 264209, China.
Research Center for Biological Adaptability in Space Environment, Institute of Space Sciences, Shandong University, Weihai, Shandong, 264209, China.
Heliyon. 2023 Feb 9;9(2):e13560. doi: 10.1016/j.heliyon.2023.e13560. eCollection 2023 Feb.
Life information searching is a hot point for Mars exploration. Ancient Mars was very likely to reach a habitable environment, and there was a real possibility of arising life on Mars. However, the current Mars has a harsh environment. Under such conditions, life materials on Mars are supposed to have taken the form of relatively primitive microbial or organic residues, which might be preserved in some mineral matrices. Detection of these remnants is of great significance for understanding the origin and evolution of life on Mars. The best detection method is in-situ detection or sample return. Herein, diffuse reflectance infrared spectroscopy (DRIFTS) was used to detect characteristic spectra and the limit of detection (LOD) of potential representative organic compounds with associated minerals. In view of high oxidation due to the electrostatic discharge (ESD) during dust actives on Martian surface. The degradation of organic matter by ESD process was studied under simulated Mars conditions. Our results show that the spectral characteristics of organic matter are significantly different from that of associated minerals. The different organic samples have different mass loss and color change after ESD reaction. And the signal intensity of infrared diffuse reflection spectrum can also reflect the changes of organic molecules after ESD reaction. Our results indicated that the degradation products of organics rather than organic itself are most likely to be founded on current Martian surface.
生命信息搜寻是火星探测的一个热点。古代火星很可能达到了宜居环境,并且火星上确实有可能出现生命。然而,当前的火星环境恶劣。在这种条件下,火星上的生命物质应该是以相对原始的微生物或有机残留物的形式存在,它们可能保存在某些矿物基质中。探测这些残留物对于理解火星生命的起源和演化具有重要意义。最佳的探测方法是原位探测或样本返回。在此,利用漫反射红外光谱(DRIFTS)来检测潜在代表性有机化合物与相关矿物的特征光谱和检测限(LOD)。鉴于火星表面沙尘活动期间因静电放电(ESD)导致的高氧化作用,在模拟火星条件下研究了ESD过程对有机物的降解。我们的结果表明,有机物的光谱特征与相关矿物的光谱特征有显著差异。不同的有机样品在ESD反应后有不同的质量损失和颜色变化。并且红外漫反射光谱的信号强度也能反映ESD反应后有机分子的变化。我们的结果表明,在当前火星表面最有可能发现的是有机物的降解产物而非有机物本身。