NASA's current planetary-protection policies reflect a bygone era of space exploration and need to be updated, a new report argues.
Planetary protection refers to the effort to keep the solar system as pristine as possible. The main goals are to minimize the odds that our spacecraft infect other worlds, such as Mars, with Earth microbes (a process known as forward contamination) and to reduce the risk of alien bugs getting loose on our planet after sample-return missions (back contamination).
NASA's planetary-protection guidelines follow those established by an international scientific organization called the Committee on Space Research (COSPAR), which began such work way back in 1958. The U.S. space agency's policies have changed some over the decades, but NASA recognized that additional revisions are likely needed now to deal with the fast-changing exploration landscape.
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Those changes are occurring on multiple fronts. For example, NASA has taken real steps toward sample-return missions. The agency's next Mars rover, which launches next summer, will collect samples for eventual transport to Earth (though when this latter step will occur is unclear at the moment).
In addition, tiny cubesats are now capable of flying interplanetary missions, as NASA's MarCO Mars probes showed last year, potentially allowing a wide range of organizations to launch probes to various cosmic destinations.
Astronauts will set foot on multiple worlds in the not-too-distant future as well, if all goes according to plan. NASA aims to land people on the moon by 2024 and on Mars in the 2030s. And SpaceX is building a giant spaceship called Starship that may get people to the Red Planet even sooner than NASA does.
So, in April, NASA established a Planetary Protection Independent Review Board (PPIRB) to take a look at the agency's policies in this realm. The PPIRB was instructed to start this work in late June and have it all done three months later. The board met this ambitious timeline. PPIRB submitted a report of its findings to NASA last week, and the agency published the report today (Oct. 18).
The PPIRB, which was chaired by planetary scientist Alan Stern of the Southwest Research Institute in Colorado, came up with nearly 80 findings and recommendations. One of the first findings the team made was a recognition that the exploration landscape will continue to change rapidly in the near future, as scientific knowledge about cosmic bodies improves and more players get into the spaceflight game.
Therefore, "we've recommended that NASA conduct a process like this IRB at least twice per decade going forward, to take into account new findings, new entrants and new technologies, both on the scientific side and on the spaceflight side," Stern, the principal investigator of NASA's New Horizons mission, said during a teleconference with reporters today.
The PPIRB team also recommended that NASA reconsider how it categorizes missions from a planetary-protection perspective. At the moment, that system appears to be overly broad and antiquated, Stern said.
For example, all missions to the surface of Mars are "Category IV" projects, which are subject to stringent spacecraft-cleaning requirements. But data gathered by multiple Red Planet craft over the years suggest that significant portions of Mars are hostile enough to Earth life that we shouldn't worry too much about contaminating those areas. Such regions could be downgraded to "Category II" destinations, reducing the cleaning burden, and thus the prices, of missions targeting the spots, Stern said.
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A similar reassessment should be done of the moon, which is now entirely a "Category II" world. Some parts — the ones away from the water-ice-rich poles, for example — could be reclassified as "Category I," Stern and the 11 other PPIRB board members wrote.
"The IRB wants to see more exploration to do more science. We want to open up the ways that Mars, the moon and all of these other spectacularly interesting objects across the solar system can be explored," Stern said.
"And so we want to move from this sort of '60s-'70s point of view that all of Mars should be treated precisely one way, and all of each world should be treated one way, to this more nuanced view, where we differentiate between different sites on the surface in order to enable more science to be done," he added.
The review board didn't tell NASA how to reclassify such worlds, which parts of Mars should be "Category IV" and which should be "Category II," for example. Stern and his colleagues just recommended that the space agency should undertake this work, and soon.
The board also recommended that NASA accelerate the development of the facility here on Earth that will receive and house the samples collected by the 2020 Mars rover, to make sure our planet is ready for this epic and unprecedented delivery.
And Stern and his colleagues advised the space agency to start educating the public about the planetary-protection aspects of the first crewed Mars missions soon — now, if possible — so people are ready for those as well.
"We recognize as an independent review board that there [is] a wide spectrum of opinions in the public, and a wide spectrum of knowledge and viewpoints about issues related to planetary protection," Stern said. "NASA needs to get ahead of that ball and start communicating proactively about both forward- and back-contamination issues."
The space agency can take some guidance in this matter, he added, from its proactive communication efforts surrounding the use of nuclear power aboard spacecraft, another issue about which many nonexperts have expressed strong opinions.
There are many more findings and recommendations, far too many to discuss in this story. You can read the entire 48-page PPIRB report here.
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Mike Wall's book about the search for alien life, "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), is out now. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.
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