A group assessing planetary protection measures said that spacecraft on Mars does not need to undergo deep cleaning processes as they did previously before leaving Earth.

NASA has mandated various levels of stringency for minimizing a spacecraft's bioburden since 1982, including "clean room" assembly or partial sterilization of components. The new study aims to avoid dangerous terrestrial pollution from spreading to Mars and interfering with the hunt for indigenous life on the planet.

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(Photo : NASA/JPL-Caltech on Wikimedia Commons)
This illustration depicts NASA's Perseverance rover operating on the surface of Mars that landed at the Red Planet's Jezero Crater on Feb. 18, 2021.

Not Every Mars Spacecraft Need Deep Cleaning

Space.com said robotic missions to some parts of Mars might be carried out with less stringent "bioburden" criteria. The guideline usually aims to prevent the accidental carrier of Earth-based microorganisms to Mars.

The research claims that harsh circumstances on Mars' surface, such as high levels of ultraviolet (UV) radiation, a scarcity of permanent liquid water, and severe humidity and temperature swings, render the survival, development, and proliferation of terrestrial species improbable. Furthermore, parts of the Martian subsurface with no ice, down to a depth of about 1 meter, are not habitats where terrestrial species might thrive.

On the other hand, Earth-based microorganisms may potentially survive in subterranean areas on Mars, such as cave systems. Relaxed bioburden criteria might be suitable for robotic missions that do not reach such regions or "buffer zones" around subsurface access points and do not descend below 1 meter into the planet's subsurface, according to the research. Wind conditions and estimations of microbial survival time in the landing environment would be used to define buffer zones.

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How NASA Spacecrafts Undergo Deep Cleaning

Continued pre-launch cleaning precautions and decontamination of equipment after landing and careful mission planning to use naturally sterilizing UV and cosmic radiation might assist reduce danger. National Academies of Sciences, Engineering, and Medicine recommends that the effectiveness of such in situ methods for reducing terrestrial contamination be validated before they are used. Better estimates of habitat connectivity, subsurface brine and ice, and improved knowledge of subsurface access points, be used to assess the risks of harmful contamination.

NASA should explore implementing proven risk management techniques for any missions that have lower bioburden criteria, which might deliver additional advantages in an increasingly complicated planetary protection environment.

NASA Continues To Discuss Planetary Defense

For some years, NASA has been debating how to handle the planetary defense. In 2019, the agency formed an independent review board to account for planetary protection. The study looked at the entire field rather than the narrow lens used in the latest report.

In a statement at the time, associate administrator for NASA's Science Mission Directorate Thomas Zurbuchen said that they want to be ready for this new environment with thoughtful and practical policies that enable scientific discoveries while also preserving the integrity of our planet and the places they visit.

Newer approaches may better reflect real danger, according to the experts on the committee, and actions after arrival can also assist in cleaning the spacecraft, further complicating the image of planetary protection rules.

The study also mentions two areas with no planetary conservation guidelines — human trips to Mars and commercial missions to Mars that do not include NASA.

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