Serina Diniega 
Planetary Scientist  

Serina Diniega, HiRISE Team Member What’s your current position and what does your research focus on?
My science interests are in understanding how landforms like dunes, gullies, and lava flows come to look the way they do. I develop mathematical and physical models of the physical processes that act on a planet’s surface, moving material around. I then use these models to connect what we can see and measure on a planet’s surface with the physical conditions that existed as the landform was created and evolved into its present state. For example, I have a model that moves sand around, blown by the wind, and see how dunes and dune fields look under different wind speeds and directions and different sand amounts. Much of my work involves looking at and trying to understand remote images of planetary surfaces, usually of the Earth or of Mars.

In addition to my science work, I work for NASA’s Mars Program Office, helping to organize meetings and documents that assist and enable the work done by the different missions and by our science community. I have also worked in space mission operations, which involved putting together the sequence of observation commands used by the Mars Reconnaissance Orbiter.

What got you interested in planetary science?
Planetary science is my chosen “application” of the theoretical models I enjoy working with. My Ph.D is in applied mathematics as I find great value in expressing ideas as equations: if you can describe a physical process (like wind-blown sand) as an equation, then you have a very large set of mathematical tools to help you predict how things are connected and which parts are important.

While an undergraduate at Caltech, I took a lot of geology classes as they were fun, and it was in one of those classes that I was introduced to the study of planetary surfaces. In these studies, a scientist may only have one image taken at one moment in time – and from that, she tries to understand that surface’s entire history! It’s very different from studies of Earth surfaces where one can usually go and dig around to get more information, or even look at historical records or legends to see what happened in the past. By developing a model of what we think happened to that surface, we can try to test our ideas and figure out which make the most sense, and then take our one small bit of information in the picture and extend it to understand what the planet’s surface was like in times past, or what it may become in the future.

Why is your subject of study/research important to you?
By learning more about how landforms look and evolve on other planets, we learn a lot about processes that also occur on the Earth. For example, the field of dune studies was greatly advanced when we had a model that worked on both Earth and Mars, despite the differences in gravity and atmospheres. We could finally really test ideas about how gravity or air density play a role in how sand is blown around, and this helps us better understand and model dune fields on the Earth!

And sometimes we find a landform that is completely different from anything we see on the Earth – which gives us a glimpse into how just varied and wild nature can be! For example, on Mars there are long troughs that extend down some dune slopes – some of these troughs are more than a mile long, and approximately 6 to 8 feet wide! We think these are formed by giant slabs of frozen carbon dioxide (dry ice) that form in the winter and break off in chunks as the spring begins to warm them. These blocks slide easily down the dune slopes, hovercrafting on a cloud of carbon dioxide gas that sublimates from the bottom of the warmed block and carving out a shallow trough. When the blocks get to the bottom of the slope, they continue to sublimate as the season warms and eventually disappear, leaving a large pit.

On Mars, this activity happens every winter, as the Mars atmosphere is mostly made of carbon dioxide and during the cold winters this carbon dioxide gas will freeze and accumulate onto the surface in thick layers. On the Earth, we never find dry ice lying around naturally – it has to be created (and purchased in the supermarket).

What would you suggest to a young person to study if he/she is interested in planetary science?
Planetary science is a very wide and interdisciplinary field – tools and perspectives and experiences from chemistry, physics, geology, mathematics, and biology are all needed to better understand the landforms and atmospheres that we see on the Earth and other planets; hardware and software engineering is needed to design the instruments we use for the observations and understanding the limitations and strengths of the measurements we make; and communications are vitally important for sharing information between people in different fields and for sharing our advances with the public. It’s a really fun area to work in as you can specialize in the specific topics you enjoy, and then discuss ideas and collaborate with other people who focus on the other areas. Thus, study the area(s) that you enjoy, and also learn about planetary science questions (including perhaps Earth science questions) and the answers we have so far. Then think about how your main area(s) of interest could contribute towards further answering those questions and talk to people (students, professors, scientists, engineers) about those possibilities.

About HiRISE
The HiRISE camera onboard the Mars Reconnaissance Orbiter is the most powerful one of its kind ever sent to another planet. Its high resolution allows us to see Mars like never before, and helps other missions choose a safe spot to land for future exploration.

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. Lockheed Martin Space Systems is the prime contractor for the project and built the spacecraft. The HiRISE camera was built by Ball Aerospace & Technologies Corp. and is operated by the University of Arizona.