Detection Methods for the Origin of Methane on Extraterrestrial Bodies

The search for signs of extraterrestrial life is regarded as a core objective of current deep space exploration. As the simplest organic compound, methane ( \mathrmC\mathrmH_4 ) serves not only as a precursor for the synthesis of complex organic matter on planets but also as a pivotal biomarker for tracing biological activities and geological evolution; consequently, the detection and analysis of its origin are of great significance. Unique isotopic signatures are imparted to methane by distinct formation mechanisms, making isotopic composition the key to discriminating its sources. In this review, the sources and analytical criteria of terrestrial methane are first introduced. Subsequently, in-situ spectroscopic and mass spectrometric detection technologies suitable for deep space missions are compared with high-precision laboratory analysis methods based on sample return, and the principles and typical applications of these technologies are discussed. It is indicated that while the verification of existence and concentration measurement of methane on extraterrestrial surfaces can be achieved with existing technologies, significant uncertainty remains in the detection of life signs. Finally, the limitations of current detection techniques and trends for future development are summarized.