I was an original member of NASA’S Planetary Quarantine Advisory Panel (PQAP). Before and ever since then,
I have had a deep interest in avoiding interplanetary cross-contamination with living organisms.
My concern was three-fold:
- Ethical - not to interfere with another planet’s natural development.
- Public health - not to endanger us or Earth’s Biosphere with alien pathogens, and
- (I admit of greater personal concern to me) - to prevent any invalidation of the life
detection experiment (“Gulliver,” later named “The Labeled Release Experiment - LR”) I was
developing for NASA to probe Mars. I feared a positive life test by my experiment might be
dismissed by attributing it to viable contaminants brought from Earth.
Indeed, in 1956, NASA established PQAP out of the concerns expressed in 1 and 2 above. In 1958, the
international Committee on Space Research (COSPAR) called for the sterilization of any spacecraft destined for Mars.
NASA accommodated this request by subjecting it’s two Viking spacecraft to chemical and thermal treatments to reduce
the probability of either spacecraft carrying a viable microorganism to one million-to-one. The cost was approximately
$250 million, some one-third the cost of the entire mission.
However, after Viking, 1976, no other spacecraft has been terminally disinfected. Thus, the Viking data from Mars are the
only pristine data we will ever see from the red planet. AND the LR results were positive for living microorganisms at
both landing sites some 4000 miles apart. However, absent the claim of terrestrial contamination, skeptics raised many
other issues to explain away the LR discovery of life. Hesitant to make such a claim because of its immense import, I and
my Co-Experimenter, Dr. Patricia A. Straat, studied new data from Mars and Earth (the latter mainly the finding of
extremophiles living under Mars-like conditions), and, in 1997, concluded that the LR had made that historic discovery.
In the 44 years since the LR results came down, dozens of abiotic explanations of the LR Mars data have been proposed.
Under NASA support, Dr. Straat and I spent three years seeking a plausible non-biological explanation, in vain. And none
of the aforementioned explanations has withstood scientific scrutiny. Even so, NASA continues to deny the Viking LR results
as evidence for life. This, despite the fact that the LR results have been heavily re-enforced by continuing data from
succeeding missions, especially Curiosity. All elements essential for life have been found in the Martian soil, in which
liquid water and complex bio-type organic compounds have also been detected. Absence of the latter two named findings were
the principal reasons long-cited against acceptance of the LR data.
Over the years since Viking, the Space Studies Board (SSB) of the National Academy of Sciences, Engineering and Medicine has
produced reports on planetary protection. NASA requested the SSB to review the development of the evolving policy. This effort
culminated in a report (NASA Planetary Protection Independent Review Board, NASA, 2019). NASA also requested the SSB review that
report and an earlier one on planetary protection for consistency, resulting in its current policy.
All of the above is presented to serve as background for NASA’s current “Mars Sample Return Mission (MSR)” and its Artemis
program, and to show that NASA is fully aware and appreciative of the contamination problem. This is particularly true in the time
of the COVID-19 pandemic that many view as a harbinger of a possibly infected sample from Mars. In fact, this vision might result
in the Mars samples being sent to the moon or to the ISS for safer analysis, as I have advocated.
However, the space agency’s actions have so far completely ignore its deeply-expressed concerns of back contamination, as do its
plans for its near-term launches to Mars. The Perseverance spacecraft, scheduled to lift-off for Mars in July of 2020, will not have
been disinfected, in common, as stated above, with all launches since Viking. COSPAR currently recommends Viking-type treatment of
spacecraft exploring possible habitats, even if not bearing life detection instruments. (Category IVc: “... any region of Mars where
liquid water occurs or can occasionally occur”). NASA’s procedures constitute a startling violation of NASA’s well-developed and
Dr. Gilbert V. Levin presenting his evidence for life on Mars at the 2016 40th Anniversary of the NASA Viking mission to Mars. Photo by Barry E. DiGregorio.
A graphic depicting how Levin’s Viking LR experiment results from Mars compares to a California soil he tested. Photo by Barry E. DiGregorio.