Dr. Delia Santiago-Materese wants things to get complex

From terrestrial animals to experiments in microgravity and Martian clouds, this NASA program scientist’s career path links diverse challenges. Today, she supports a mission to Saturn’s moon Titan, a world teeming with organic molecules that could hold valuable clues about the origin of life.

When novelty is your hobby, you already have a large part of the recipe for a career full of challenges. That is why Dr. Delia Santiago-Materese describes her path within NASA as “meandering.” Her diverse roles have taken her to low Earth orbit, to the clouds of Mars, and to the surroundings of Jupiter. Now, they are also bringing her closer to the surface of Titan, an intriguing moon of Saturn. Woven together by her exploring spirit and a perennial curiosity, all these experiences have one point in common: life.

Today, Santiago-Materese is part of the Planetary Science Division at NASA Headquarters in Washington. The main decoration in her office is a model of Jupiter, larger than a basketball, resting next to a scale model of the spacecraft exploring it, Juno. Small black and red pins with the inscription “Dragonfly” rest in the center of a round table. Several framed diplomas cover a wall. From here, Santiago-Materese does “a little bit of everything” on any given workday as a program scientist for the Juno and Dragonfly missions, and for the Discovery program, which features a portfolio of several missions in our cosmic neighborhood.

This medley of roles is no coincidence. Santiago-Materese describes herself as someone who does not pursue a single goal, but rather diverse interests that she discovers along the way. “I am always looking for something new to add to my experiences,” she says, “because I think I also get bored easily.”

The daughter of a military family, Santiago-Materese was born in Spain by coincidence. Her roots are actually on another continent: her mother is Mexican-American and her father is Puerto Rican. From her time in Spain, she only keeps some baby photos; she lived part of her life in Texas and then in California, which she considers her home—despite having spent her childhood summers in San Sebastián, Puerto Rico. It was in the Golden State where she first imagined herself as a veterinarian and decided to study Biological Sciences. And it was during her studies at Stanford University, “just around the corner” from NASA’s Ames Research Center in California’s Silicon Valley, that Santiago-Materese discovered astrobiology.

This elective course brought her closer to a discipline that, to some extent, was in its infancy. Today, NASA’s Astrobiology Program investigates life in the universe on many levels: how it began, how it evolved here on Earth, and where it might exist elsewhere. And that was how Santiago-Materese realized that biology and space were not two isolated things, she recounts.

Rodents, Insects, and Martian Clouds

After finishing her studies, Santiago-Materese completed a one-year internship at the San Francisco Zoo. But the unknown that astrobiology presents continued to intrigue her, so she went back to one of her professors to inquire more about it. She asked around and found someone at Lockheed Martin, a company that often contracts with NASA on space projects. They were looking for people for a new project studying the nutrition of the food bars for rodents traveling to space aboard the space shuttle.

Santiago-Materese has applied that formula ever since: identifying what truly interests her and finding the right person to ask questions. If people “don’t know what you’re interested in, they can’t help you,” she explains. After experience with the Space Shuttle Program, including managing databases for science payloads aboard the space shuttle, she went on to work with the International Space Station, which was then beginning its legacy of over 25 years in Earth orbit. She supported the development of biological experiments in microgravity, this time with fruit flies. But Santiago-Materese wanted to keep moving farther from Earth and investigate future space destinations.

This curiosity led her to the Martian sky. As part of her graduate studies at the University of California, Santa Cruz, Santiago-Materese investigated the Martian atmosphere, focusing on ice in the clouds and the development of climate models for the Red Planet. She earned her master’s degree and would later return to complete her doctorate under the NASA Pathways program, which is one of the agency’s primary early-career hiring pathways. She would defend her thesis six months after giving birth to her first daughter (one of the achievements she is most proud of, she says). That is why, although she loves the “weird” planets of the outer solar system, she is “more of a Mars person,” by training.

At NASA Ames, Santiago-Materese held various roles, ranging from social media and open science to lunar sciences. She then became a program officer for the Solar System Workings program in the Planetary Science Division at NASA Headquarters as part of a detail, or temporary assignment. And then, she took off for Maryland along with her family.

Enabling Science

Santiago-Materese sums up her current role as a program scientist as the “science liaison” between NASA Headquarters and a mission. “When you do program scientist work, you might not be specialized or an expert in the exact science, but you need to be able to understand it and talk about it, to understand its importance,” she explains. “In general, we are supporting other people so they can do science.” In this endeavor, being someone who “gets more energy from working with people” is useful… and necessary: “You are having conversations all day long” with colleagues from different disciplines— from science and engineering to finance.

The Juno mission, in orbit around Jupiter since 2016, and Dragonfly, which is scheduled to launch no earlier than July 2028, are part of NASA’s New Frontiers program. Santiago-Materese also oversees the array of missions in the Discovery program, which includes ongoing science missions like Psyche and Lucy—heading to different asteroids—and future missions to Venus.

For Santiago-Materese, sharing her unconventional path can be valuable for students and youth in general, especially those who are unsure of what they want to do. “Your dream job,” she says, “you might not know it exists, or maybe it doesn’t exist today.” Beyond that, this zigzagging path has led her to accumulate experiences and relationships with different people, which she treasures even as she sets off for her next destination.

An Alien World

About two years out from Dragonfly’s launch, it is no surprise that this robotic mission takes up much of Santiago-Materese’s time. “Dragonfly feels like a combination of all my different experiences over time,” she reflects. And it signifies, to some extent, a return to her roots: it is an astrobiology mission. Although not designed to detect life, Dragonfly will investigate prebiotic chemistry: the chemical processes that could have led to the emergence of life on Earth.

Dragonfly will embark on a journey of about six years to the surface of Titan. The spacecraft will carry an array of science instruments and will be the first NASA science mission to explore another world by flying from location to location. This car-sized rotorcraft will touch down at various geological sites of interest to analyze the moon’s composition and its habitability potential.

When it arrives at Titan, it will encounter a landscape that is strange and familiar at the same time: it could be a window into Earth’s remote past. This frozen world has a thick atmosphere and clouds drifting across the sky; dunes, lakes, rivers, canyons and mountains. Titan even has a process equivalent to our water cycle. However, on Titan, it is not water that flows but hydrocarbons, primarily methane and ethane. “It’s a more methane-based chemistry, so it is very alien, and that is what I really love about Titan,” says Santiago-Materese. And on this moon, organic molecules abound.

These molecules contain carbon and are used by all known forms of life. They are fundamental to understanding the origin of life, as they can be produced by both biological and non-biological processes. On Titan, these organic molecules fall to the surface and form dense deposits over its bedrock of water ice. Scientists believe that the complex chemistry precursor to life could be triggered there if provided with a little liquid water, such as that generated by an asteroid impact.

Santiago-Materese is especially excited about what the Dragonfly Mass Spectrometer (DraMS) instrument will help discover. DraMS, designed and built at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will analyze samples from Titan’s surface. “The more complex things get, the more interesting things happen,” she says. “So I’m curious: just how complex do the molecules get? Will we find any interesting patterns?”

But in science, every time you ask a question, a new one arises. Dragonfly will try to answer several of them. “When you have a planet with complex chemistry but not life, what happens? What is there before life?” the program scientist wonders.

Titan, a valuable natural laboratory, “is going to completely change our understanding of what another world can be like,” she anticipates. In addition to what the scientific community expects to discover thanks to Dragonfly, Santiago-Materese is interested in the potential unexpected findings. “There are very defined science goals, but a lot of it is exploratory work,” she explains. “It is kind of nice to know that there is a big range [of possibilities], that we could be very surprised.”

By Noelia González, NASA’s Goddard Space Flight Center, Greenbelt, Maryland

Lee esta historia en español aquí.

The post Dr. Delia Santiago-Materese appeared first on NASA Science.

A cubic meter of lunar soil might be one of our best bets for finding physical proof that another advanced civilization once existed somewhere in the Milky Way, according to a new paper to be published in the International Journal of Astrobiology.

The post Could Scoop of Moon Dust Reveal Alien Technology? appeared first on Sci.News: Breaking Science News.

A provocative new paper suggests consciousness may not be unique to Earth and could arise in alien life forms far stranger than we can imagine. A new philosophical paper argues that consciousness may not be exclusive to life as we know it. According to Eric Schwitzgebel, a distinguished professor of philosophy at the University of [...]

Researchers want to explore the idea that microscopic particles shed by alien civilizations have accumulated on the lunar surface, making it an archive of extraterrestrial technology.

One of the biggest challenges in the search for alien life is that Earth remains the only example of life we know. As a result, nearly every attempt to identify biology elsewhere starts, at least partly, by looking for chemistry that resembles life here.

Researchers at the University of Glasgow are exploring a different strategy. Rather than asking whether an alien molecule looks biological by Earth standards, they propose asking a more fundamental question: How difficult was that molecule to make?

In a new study published in the Proceedings of the National Academy of Sciences, researchers demonstrate a method that combines mass spectrometry with machine learning to estimate what researchers call “molecular assembly,” or MA.

The concept comes from Assembly Theory, which attempts to quantify molecular complexity by identifying the minimum number of construction steps needed to build a molecule. Researchers argue that when highly complex molecules appear repeatedly and in abundance, their existence may point to a process that is consistently steering chemistry down particular pathways.

That could make molecular assembly useful as an “agnostic” biosignature—one that does not depend on alien life sharing Earth’s chemistry.

“There is a growing interest in ‘agnostic’ life detection strategies: methods that can identify molecular signs of life without needing an exact understanding of what that life might look like, or how it might interact with a complex, poorly characterized environment,” the researchers write. “The measured assembly index, defined as the number of steps along the shortest construction pathway, is fixed for each molecule and does not depend on external conditions, such as the environment in which the molecule might be detected or the specific ‘alien’ biochemistry from which it might arise.”

The researchers’ proposed “agnostic” approach could become increasingly important as scientists encounter tantalizing, but often ambiguous, chemical signals in the search for alien life.

Methane on Mars, phosphine reported in Venus’s atmosphere, and dimethyl sulfide proposed as a possible biosignature within exoplanet atmospheres have all attracted attention because living organisms can produce those compounds.

However, biology is not the only way to make them. Methane, for example, can emerge from geologic processes. Dimethyl sulfide is strongly associated with life on Earth, yet it has also been detected in cometary material and produced in laboratory experiments simulating primordial chemistry.

The presence of a particular molecule, in other words, does not necessarily tell scientists what produced it. Molecular assembly approaches the problem from a different angle. Under Assembly Theory, researchers calculate the shortest possible pathway for constructing a molecule from simpler building blocks. A molecule with an MA of 40, for example, has a shortest construction pathway twice as long as one with an MA of 20.

The reasoning is rooted in probability. Undirected chemistry has an enormous range of possible molecular structures. As molecules become more complex, the odds of repeatedly producing the same highly elaborate structure shrink unless something constrains the process.

Biological systems store and use information to direct chemical reactions toward particular outcomes, permitting organisms to manufacture the same complicated molecules again and again instead of wandering randomly through the immense space of possible chemistry.

Previous experiments cited in the study found an approximate dividing line between abiotic and biological samples at an assembly index of around 15.

Perhaps more importantly, in the search for alien life, scientists would not necessarily need to know what a molecule is before recognizing that it is unusually complex.

That could be especially useful on worlds such as Mars, Europa, Enceladus, or Titan, where spacecraft may encounter compounds unlike anything commonly found on Earth.

Several proposed planetary missions use, or could use, mass spectrometers. These instruments analyze molecules by measuring ions’ mass-to-charge ratios.

More sophisticated multistage mass spectrometers can repeatedly break molecules apart, giving indications of their structure and assembly history. But spacecraft operate under severe limits on power, mass, computing capacity, and instrument complexity. Many planetary missions, therefore, rely on simpler, single-stage mass spectrometry.

To close that gap, the researchers trained an XGBoost model on standardized mass spectra from the National Institute of Standards and Technology Chemistry WebBook. The model learned to estimate molecular assembly directly from single-stage spectra.

According to the study, it reduced relative mean squared error threefold compared with the best-performing baseline model, cutting the figure from 0.12 to 0.04.

The model also tended to underestimate molecules with especially high MA values. For a life-detection system, that bias could be preferable. It means the model was more likely to be conservative than to classify a molecule as an unusually strong biosignature mistakenly.

Researchers envision future spacecraft using this kind of analysis autonomously. A rover or lander that detects molecules with unusually high assembly scores might flag the surrounding area for closer inspection, prioritize certain samples, or identify material worth returning to Earth.

The study explicitly evaluated conditions designed to resemble instruments proposed for missions to Titan and Europa.

The same framework also raised another, more speculative possibility: when the researchers compared very large molecular databases, they identified several medical compounds with unusually high MA values. Their complexity was not the product of biology alone, but of deliberate human synthesis.

That led the team to suggest that particularly complex artificial molecules might serve as “molecular technosignatures”—chemical evidence oftechnology, rather than life itself.

For now, however, the method remains far from being a ready-to-fly alien-life detector. Instrument settings strongly affected performance. In simulated experiments, changing impact energies could nearly double prediction error, while one comparison increased it by more than 2.3 times. Molecules that break apart unusually easily can also cause the model to overestimate assembly, while molecules that resist fragmentation may be underestimated.

The researchers therefore describe the study as a proof of concept. Turning the approach into an effective tool for planetary investigation would require standardized databases, careful instrument calibration, and chromatographic separation to isolate individual molecules before analysis.

Future versions could also combine mass spectrometry with other techniques, including nuclear magnetic resonance or infrared spectroscopy. Infrared measurements, the researchers suggest, extend aspects of the approach to the remote study of exoplanet atmospheres.

Yet the wider goal is significant. Instead of deciding beforehand what alien biology should produce, scientists could search for evidence that a process has persistently directed chemistry toward highly specific, complex outcomes.

“In this work, we presented a proof-of-concept demonstrating the potential use of ML to predict the MA molecular complexity as a biosignature from in situ mass spectrometers during future space missions,” the researchers write. “Although the application of ML in life detection remains a nascent endeavor, it holds significant promise.”

The recent study, “Molecular Assembly as a Universal Biosignature Measurable by Mass Spectrometry,” appeared in Proceedings of the National Academy of Sciences.

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com