Perseverance and Environmental Site Characterization : What can we learn from NASA’s latest Martian Adventure?

We have been living during a period where the need to persevere has never been stronger. And this week’s incredible, exciting, and uplifting landing of the US National Aeronautic and Space Administration’s, or NASAs, Perseverance vehicle on the Martian surface after a decade of development, the work of thousands, a nearly 7 month interplanetary journey and the coined “seven minutes of hell” landing, may have provided one of the most unifying and demonstrable examples of what can be accomplished – in any field – if a community, in this case, the scientific community with government backing and public financial support, perseveres together to accomplish something truly great[1]. Defined by most references, such as Merriam-Webster, as the “continued effort to achieve and succeed despite difficulties” or simply, steadfastness, the achievement of placing this robotic extension of the human imagination on our planetary neighbor is truly astounding.

What is perchlorate? Is it alien?

In 2009 I wrote a short opinion piece titled Perchlorate on Mars and the Future of Subsurface Characterization and Remediation[2] in the National Ground Water Association journal Ground Water. My objective was to highlight the amazing news that NASA’s Phoenix Mars Lander had scooped up some Martian soil and analyzed it, right there, 150 million miles from the nearest analytical laboratory on Earth, and detected the presence of perchlorate (ClO4-) a key environmental constituent. Since that 2008 detection, subsequent sampling events and rovers, including NASA’s Curiosity[3] have shown perchlorate and other oxy-chlorine compounds to be widespread in the Martian environment.

If you’ve followed the saga of perchlorate, you know that it has been identified as a contaminant since the mid-1990s, recognizing also that the water quality standard for this compound has been adjusted up and down and in and out by both Federal and State regulators depending on jurisdiction here in the USA. Perchlorate is produced naturally in Earth’s atmosphere through reactions of chlorine with ozone (and from a combination of complex atmospheric and surface based reactions on Mars according to the Archer study[4]), but it is importantly a strong oxidizer and commercially has been a key component of rocket fuel, road flares, and fireworks. As perchlorate salts are readily soluble, they have found their way into terrestrial surface and groundwater where environmental risk has been a focus of attention.

Mars' soil - what's in it for us (earth)?

This blog is not about perchlorate, however. Then, as today, my interest is in the recognition that by using scientific know how, not just to get to Mars, but to analyze the chemical composition of the red planet’s soil, we were achieving new ways to more completely understand our environment and were doing so without having to collect data using direct human presence. This achievement led me to consider the pursuit of scientific development in our environmental restoration practice and specifically related to the needs of site characterization. Specifically, I noted the developing use of remote sensing and innovative methods to collect and analyze environmental samples and expressed that our practice was on the cusp of game-changing techniques that would greatly enhance our ability to understand complex environmental and contaminant sites, and with less bias, effort, and expense. So, how well have we achieved this vision over the past 13 years?

In short word, we have done quite well. Writing a summary about projects showcased in the 2019 compilation book Engineering with Nature: An Atlas[5] developed by the U.S. Army Corp of Engineers, Engineering News-Record editor Tom Sawyer wrote: “…one technology finding a sweet spot…is drones, which have the ability to scope project areas, survey sites and monitor project execution and performance over large areas of difficult terrain swiftly, safely and repeatedly, with a light touch on the environment.”[6] I believe that most of us would agree that the use of unmanned aerial vehicles (UAVs) has exploded in use over the past decade to collect information from atmospheric, terrestrial, hydrologic, and ecologic systems that we would never think possible just a couple of decades ago. But it is not just from “flying” (and including the more advanced use of satellite imagery and sensing for earth system analysis) that we’ve succeeded. The use of innovative land-based equipment that can rapidly sense changes in molecular and geochemical conditions on environmental sites are giving us new insights and fidelity into the incredibly complex environment of chemical fate and transport. Consider the use of newly developed in-ground sensors for monitoring reduction-oxidation conditions in the subsurface environment in real time as developed by researchers at Colorado State University.[7] Because redox conditions so critically govern how organic chemical transform, and the valence transition of inorganic constituents, being able to see real time changes during precipitation recharge or even atmospheric infusion into the subsurface will give us great insight in not just environmental risk from released contaminants but also provide better clues as to how to mitigate the occurrence and migration of subsurface contaminants.

Another advance for a critically important topic concerns the widespread presence of microplastics in nearly all earth systems. With respect to this area, researchers with the University of Newcastle, Global Centre for Environmental Remediation, New South Wales, Australia and the Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) are figuring out better ways to use non-destructive processes including Raman spectroscopy to better identify and then map numerous types of plastics in an environmental sample.[8] Knowing the type and composition of the plastic material (and its size, distribution, and condition) in a given environment will greatly improve our ability to develop mitigation methods and preventative care.

Perseverance landing and the future

We have numerous, maybe hundreds or thousands of advances in characterization, in analytical techniques, in interpretive analysis (we haven’t even discussed the new Artificial Intelligence methods and machine learning algorithms that are allowing us to better predict, visualize and solve key environmental problems), and in the ability to collect, store, and organize massive amounts of information. We have new concerns from “emerging” contaminants such as the perfluoroalkyl substance (PFAS) family of compounds. We have the critical problem of climate-change induced influence on both terrestrial, hydrologic, and aquatic systems. We have the need for rapid prediction and detection of natural hazards (flooding, wind events, chemical releases) to better protect human and ecological receptors. And we need faster, more reliable, and yes, less expensive methods to achieve these objectives.

We are environmental consultants, academicians, politicians, regulators, industry, public taxpayers and government officials who control funding and who each have an interest in the development of innovative and advanced technologies to help us understand our environment and protect ourselves and our society from harmful conditions that we too are responsible for. As a geologist and environmental consultant with the BBJ Group, as an academic, as a practitioner with over three decades in this practice, I can say I am duly impressed with what we have achieved. But I also feel we have not accomplished nearly enough and we must request that scientific pursuit be allowed to flourish and expand to help solve our many pressing issues. We can develop the most accurate and reliable site conceptual models of terrestrial, and outer planetary systems. And we will be amazed at the advances that the new NASA rover and its cousin, the soon to fly Martian helicopter Ingenuity, will show us. We can, and we will, solve the problems that we are tasked with – and we will with science, with vision, and with the perseverance that brought us to this practice and career in the first place.

Scott Warner is also a Doctoral Researcher – Global Centre for Environmental Remediation, University of Newcastle, NSW Australia

References

[1] Mars Perseverance Rover | NASA

[2] Warner, S.D., 2009. Perchlorate on Mars and the Future of Subsurface Characterization and Remediation. Groundwater Monitoring & Remediation 29, 51–53.

[3] Archer, P.D., et al., 2019. Perchlorate on Mars – Overview and Implications. https://www.hou.usra.edu/meetings/ninthmars2019/pdf/6233.pdf

[4] Ibid

[5]https://erdc-library.erdc.dren.mil/jspui/handle/11681/27929

[6]https://www.enr.com/articles/46373-drones-find-sweet-spot-in-environmental-engineering

[7] Sale, et al., 2020. https://doi.org/10.1016/j.jhazmat.2020.124403

[8]https://www.crccare.com/news/new-method-for-detecting-microplastics-beneath-our-feet