NASA rules that govern the potential spread of earthly microbes to other planets—and the potential return of alien life back to Earth—are often anachronistic and require broad rethinking, according to a report released today by an independent agency advisory panel.
Planetary protection, as such efforts are known, remains a worthy goal, the report emphasizes. But many of the ways it is implemented, which date back to rules conceived at the beginning of the space age, have driven costly and sometimes questionable efforts, and do not make sense given current scientific knowledge, says Alan Stern, a planetary scientist from the Southwest Research Institute in Boulder, Colorado, who led the 12-member panel reviewing NASA’s efforts. “We want to move from this 1960s–70s point of view that all of Mars was treated one way.” Planetary surfaces are more nuanced than that, he says.
Concerns over planetary protection have often seen NASA make great efforts to prevent microbes from going to space. Its martian robots are assembled in cleanrooms, with many components baked in ovens or doused in chemicals. Famously, its Viking landers for Mars in the 1970s were baked in purpose-built ovens. But these protections have often been costly and, in the view of some scientists, overly burdensome.
The new report seems to echo this view. For example, NASA should move beyond a rigid use of spore counts, which can only tally microbes that can be grown in a laboratory (many can’t), to determine the life inhabiting its spacecraft, the report says. Modern techniques that use genomic sequencing to monitor cleanrooms are now available, and these can be combined with probabilistic risk analyses of whether harmful contamination of another world would be likely.
NASA should also rethink how it classifies the surfaces of the Moon and Mars, the report says. All of the Moon is now classified as potentially of interest to research on the origins of life, meaning NASA doesn’t want to contaminate it with imports from Earth. But few scientists now view the Moon as an important site for studying such questions—except for its poles, where ice that might have helped sustain life exists. Reclassifying much of the Moon’s surface as nonessential for biological studies would simplify exploration for NASA and other space agencies—along with commercial actors. Similarly, the report says, much of Mars has been treated as if microbes that landed on its surface could survive and be transported to regions thought to host water and allow the replication of life. But many scientists think that outcome is unlikely and worth rethinking.
Because it’s possible that humans could return to the Moon, and arrive on Mars, in the next few decades, NASA should also think about establishing two management zones on the bodies, the report adds. The first would create protected astrobiology zones considered essential for the exploration of possible extinct or existing life. The second would be human exploration zones that invariably would be exposed to the zoo of microbes that accompany humans anywhere they go.
NASA also needs to redo its planetary protection guidelines for returning samples to Earth that will be collected by its Mars 2020 rover. Earth has long been bombarded by meteorites that originated from Mars with no known biological harm, it notes. Although it will remain important to prevent earthly microbes from contaminating samples collected by the rover, the agency should re-evaluate the risks that such samples could present to life on Earth.
NASA is not a regulatory agency, but given the increasing commercial interest in space, the report notes it needs to work with the Federal Aviation Administration and other federal agencies to find a way for commercial actors to incorporate planetary protection into their development. This concern was sparked, especially, by the Tesla Roadster that SpaceX launched into space on the first flight of the Falcon Heavy last year; the car received no planetary protection evaluation before being released into space.
The new report comes as NASA has already been in a period of change in its planetary protection policies. In 2017, the agency moved its planetary protection office from its longtime home in the science directorate to the Office of Safety and Mission Assurance, a place more accustomed to translating protocols into engineering practice.
The report overall matches the agency’s thinking on the topic, says Thomas Zurbuchen, NASA’s associate administrator for science. “We have a lot of momentum going forward as we modernize our approach,” he says. In the future, NASA will seek to more regularly update its guidelines, he says, while it also discusses with other nations how to update planetary protection rules set internationally by the Outer Space Treaty.
Overall, the report is a welcome development, says Alberto Fairén, a planetary scientist at Cornell University who has been agitating for a re-evaluation of planetary protection guidelines. However, it remains silent on one important point: If humans are going to invariably contaminate Mars, he says, then shouldn’t the water-rich regions most capable of supporting life be explored as soon as possible? “This is the main problem in space exploration for our generation,” he says, “because our children will see red footprints on Mars.”