Planetary Protection: Why study it? What can it teach us about finding life beyond Earth?

Universe Today has recently investigated a plethora of scientific disciplines, including impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, meteorites, radio astronomy, extremophiles, organic chemistry, black holes, and cryovolcanism, while conveying their importance of how each of them continues to teach researchers and the public about our place in the vast universe.

Here, we investigate the field of planetary protection, which involves preventing Earth-born organisms from contaminating other worlds or interfering with scientific analyses on those worlds, along with preventing contamination to Earth from returned samples. To investigate this, we present a 2023 paper in Acta Astronautica with additional insights from the study’s lead author, Dr. Athena Coustenis, who serves as the Chair of the Committee on Space Research (COSPAR) Panel on Planetary Protection (PPP), regarding what planetary protection can teach us about finding life beyond Earth, exciting aspects about planetary protection, and advice for upcoming students who wish to study planetary protection.

The paper discusses the importance of planetary protection regarding space exploration, stating, “Planetary protection enables scientific return from solar system bodies investigations and at the same time protects life on Earth. As we continue to explore our solar system by landing machines and humans on other planets, we need to ascertain that we do not bring potentially dangerous material home to Earth or carry anything from Earth that may contaminate another planetary body and prevent scientific investigations.”

The paper discusses in greater detail the COSPAR PPP and its primary goals, including offering advice or guidance to government or private space-faring organizations and ensuring extraterrestrial samples returned from outer space do not contaminate the Earth, and specifically its biosphere. Additionally, the paper discusses recent policy actions taken by the PPP for the continued exploration of the Moon, Mars, and icy moons such as Europa, Enceladus, and Titan.

For the Moon, PPP recommended steps that need to be taken to prevent potential contamination of the permanently shadowed regions of the Moon, which are hypothesized to contain large quantities of water ice and are of significant interest for the upcoming Artemis missions. For Mars, the PPP focused on safeguarding more advanced scientific endeavors, including drilling, older areas of Mars that have yet to be explored, and sample return missions, to prevent contamination of potential scientific results and Earth’s biosphere, as well.

For icy moons, which the paper notes as being “possible habitable environments”, the PPP has already expressed concerns about exploring these worlds with the Planetary Protection of the Outer Solar System (PPOOS), which was led by the European Science Foundation and funded by the European Commission and is in the process of seeking additional insights in the future. Therefore, with these intriguing worlds being considered for exploration, what can planetary protection teach us about finding life beyond Earth?

Dr. Coustenis tells Universe Today, “Finding ways to preserve scientific research in our solar system helps the quest for finding life elsewhere and protecting our own biosphere during space exploration is essential for life on Earth. Working to that end with a large group of scientists, agency representatives and other expert stakeholders is one of the most rewarding activities in my career. The valuable outcome which represents thorough, long-term studies and reviews of knowledge is achieved through consensus and distributed to the large community. We are very excited to be able to offer such a service to the community via the COSPAR Panel on Planetary Protection.”

Along with serving as Chair of the COSPAR PPP, Dr. Coustenis has extensive research experience regarding planetary surfaces and atmospheres, specifically outer solar system objects like Europa, Ganymede, Titan, and Enceladus, as these worlds are targets for future astrobiology research. Additionally, Dr. Coustenis’ research extends far beyond the solar system as she has helped distinguish and characterize exoplanetary atmospheres, as well. Regarding planetary protection, some notable publications include being a co-author on a March 2024 paper discussing planetary protection for a future crewed Mars mission and a 2023 paper discussing COSPAR requirements for exploring Venus. Given her knowledge and experience regarding planetary protection, what are some of the most exciting aspects about planetary protection that Dr. Coustenis has encountered during her career?

Dr. Coustenis tells Universe Today, “We have recently worked on the Moon exploration requirements to preserve the poles and the regions where liquid water could be found at some periods of time and are currently working on the missions that will explore icy worlds, like the moons of our giant planets that harbor liquid water oceans underneath their surfaces, as well as organic chemistry and energy sources. These could be habitable environments that we need to explore with care.”

As noted in the Acta Astronautica paper, the field of planetary protection requires international collaboration not only from a multitude of scientists, but also engineers, as they are the individuals responsible for building the spacecraft that are sent to far-off worlds for scientific exploration. Other disciplines that contribute to planetary protection include geology, physics, geophysics, biotechnology, astrobiology, biomedical, planetary science. It is through this constant collaboration of scientists, engineers, and medical professionals that planetary protection has successfully prevented contamination of planetary bodies outside the Earth, but also preventing contamination of the Earth from returned samples. Therefore, what advice can Dr. Coustenis offer to upcoming students who wish to pursue a career in planetary protection?

Dr. Coustenis tells Universe Today, “Planetary protection offers the possibility to contribute coming from many different fields, scientific, engineering, economic or legal. We need all these varied points of view in order to accomplish adequate characterizations of space missions and related requirements and also to establish the real value of planetary protection, the enabling capacity of this tool and to spread the word about what we do and how others can contribute, in particular the younger generations. So, we encourage students and early-career space aficionados to join COSPAR and learn more about our work and that of other commissions and panels within its structure so as to be able also to position themselves and engage with the space community.”

How will planetary protection teach us about our place in the cosmos in the coming years and decades? Only time will tell, and this is why we science!

As always, keep doing science & keep looking up!