Book Argues NASA Overlooked Viking's Mars Life Evidence
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- Steven Benner argues in his new book "Meet the Neighbors" that NASA's 1976 Viking landers did detect life on Mars, but the scientific community dismissed the results in favor of a non-biological explanation.
- Gil Levin's "labelled release" experiment on Viking 1 and 2 fed radiocarbon-tagged nutrients to Martian soil, which released radioactive CO2—an "indication of respiring microbial life"—alongside two other tests that produced life-positive results.
- The Viking landers' gas chromatography-mass spectrometer (GC-MS) found no organic content in Martian soil at Chryse Planitia and Utopia Planitia (6,460 km apart), leading the community to attribute the positive readings to an oxidizing surface chemical.
- NASA's Curiosity rover, which landed in 2012, has since found the Martian surface is full of organics—notably perchlorates—undermining the GC-MS-based dismissal of Viking's life-positive results, per Benner.
- Benner urges space agencies to use reusable rocketry to mount searches for existing life on Mars, focusing on microbes with RNA-based building blocks, citing ribose found in samples from asteroid Bennu.
- The book sharpens a biosecurity debate as China plans to deliver Mars samples to Earth in 2031, an issue the late Levin and Patricia Straat had pressed through a pressure group advocating off-Earth sample analysis.
Why it matters: Benner argues the Viking dismissal propagated into decades of conservative Mars exploration policy, steering agencies toward searches for ancient habitability rather than extant life. The debate becomes operational as China plans a 2031 Mars sample return, which Levin and Straat's pressure group argued should be analyzed off-Earth to protect planetary biosecurity.
