- 1Goddard Agnostic Biosignatures Collective, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- 2Center for Space Sciences and Technology, University of Maryland, Baltimore County, Baltimore, MD, USA
- 3Center for Research and Exploration in Space Science and Technology II, NASA GSFC, Greenbelt, MD, USA
Life detection in space exploration is strongly influenced by our understanding of life on Earth. However, focusing solely on "life as we know it" risks overlooking traces of unknown life. Instead of searching for specific molecules associated with terrestrial life, we propose prioritizing the detection of universal functional traits of life.
Assembly Theory (AT)1 is an agnostic biosignature framework proposing that life produces complex objects in abundance. AT determines the complexity of an object by calculating the smallest number of unique steps required to construct it, based on graph theory. Additionally, the copy number of an object—specific to the investigated environment—is factored in, reflecting how living systems select to produce objects that enhance information storage, stability, or survival. While the theoretical foundation of AT for life detection is well established, particularly for organic molecules, further work is required to use AT for sample interpretation in space exploration. Previous studies have demonstrated AT calculations using data from spectroscopy techniques (IR and NMR)2 and mass spectrometry (direct infusion ESI-MS and LC-MS)1,3. However, LC-MS is currently unsuitable for space missions due to challenges such as solvent weight and the difficulty of mixing solvent gradients in microgravity.
Gas chromatography-mass spectrometry (GC-MS) offers a well-established instrument alternative for space exploration3, addressing the limitations of LC-MS while still providing analyte separation. GC-MS was deployed in the Viking mission in 1976, is currently used by Curiosity's SAM instrument, and will be featured in future missions like MOMA on the Rosalind Franklin Rover and DraMS on Dragonfly. Given its heritage and future applications, an experimentally validated GC-MS agnostic biosignature method is urgently needed.
Adapting AT estimations for GC-MS requires careful consideration of several parameters, including column selection, derivatization methods and consideration towards sample matrices. We will present preliminary test results of AT estimations using GC-MS and discuss how operational choices may impact the performance of this biosignature detection method. Developing a robust agnostic biosignature method compatible with instruments already deployed provides new opportunities for advancing life detection and interpreting space mission data.
1. Marshall, S.M., Mathis, C., Carrick, E. et al.Identifying molecules as biosignatures with assembly theory and mass spectrometry. Nat Commun 12, 3033 (2021). DOI: 10.1038/s41467-021-23258-x
2. Jirasek, M., Sharma, A., Bame, J. R. et al.Investigating and Quantifying Molecular Complexity Using Assembly Theory and Spectroscopy. ACS Central Science (2024). DOI: 10.1021/acscentsci.4c00120
3. Weiss, G.M., Asche, S., Graham, H.V. et al. Operational considerations for approximating molecular assembly by Fourier transform mass spectrometry. Astron. Space Sci., 11 (2024). DOI: 10.3389/fspas.2024.1485483
4. Luoth, C., Mahaffy, P., Trainer, M. al. Planetary Mass Spectrometry for Agnostic Life Detection in the Solar System. Front. Astron. Space Sci., 8 (2021). DOI: 10.3389/fspas.2021.755100
How to cite: Asche, S., Weiss, G. M., and Graham, H. V.: Experimental assembly theory estimations with gas chromatography-mass spectrometry, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13309, https://doi.org/10.5194/egusphere-egu25-13309, 2025.
