When people think of NASA, the first thing that comes to mind is probably an image of astronauts floating around the International Space Station, or perhaps the great discoveries that have come from the agency’s space programme. However, while space exploration and rocket science are among NASA’s better-known achievements, it also does cutting-edge Earth science, forging new ways to monitor the planet we call home.
I work as a contractor at NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Maryland, and my research is on Earth observation. Specifically, I use the techniques of remote sensing to process and analyse images that have been collected by Earth-orbiting satellites. The term “remote sensing” describes the acquisition of information about an object or phenomenon without actually being in contact with it, so in some ways, we are all doing remote sensing every time we use a camera. However, when used scientifically, remote sensing also involves harnessing parts of the electromagnetic spectrum that are not otherwise visible to the human eye. For example, when using infrared light, the vitality of vegetation becomes more apparent and its level of moisture is more visible.
Clarity through elimination
When I started my undergraduate studies at Northland College, Wisconsin, I followed my passion for the outdoors and the natural environment by pursuing a degree in environmental science. I was living in a small town, surrounded by all the nature I wanted, and everything was bliss. I envisioned a career with the Environmental Protection Agency, studying streams or perhaps working on some other project that would let me care for the health of the environment.
Not everything, however, was so easy. During my first year, I was in a car accident that left me paraplegic and confined to a wheelchair. My dreams of working in the field doing studies in the outdoors virtually vanished at that instant. But although I could no longer easily access the remote wilderness areas that interested me, as I once did so effortlessly, none of this worried or deterred me from having a clear idea of what I wanted in life. I just had to make an adjustment. My mind was as strong as ever and my determination to reach my goals was even greater.
After rehabilitation, I returned to my studies. As I settled into the groove of university education, I found that I enjoyed higher-level mathematics and physics, too, so I decided to take the required courses for a degree in physics as well as environmental science. As my skills and interests became clearer, I realized that I faced a dilemma: how could I combine my passion for the environment and my interest in physics into a career? The light bulb in my head lit up as soon as I took a physics course on environmental modelling. This course introduced me to the concept of remote sensing, and I was immediately hooked.
The thing that eventually paved the way to my career in remote sensing was a series of summer internships. I did internships every summer during my undergraduate years, and this not only gave me a chance to travel around the US – something I love doing – but also allowed me to apply my skills in different career environments. During the summer of 2000 I did an internship at the GSFC’s Landsat Project Science Office, where I learned the specifics of satellite imagery and its many applications to society. It was a great project to work on; not only does Landsat have the longest continuous record of satellite land-surface observation but, at the time of my internship, the programme had just launched its most recent and advanced satellite to date (Landsat 7). I was amazed by the work done there and the amount of information that can be derived from those beautiful images of Earth’s surface. For example, what some people might consider a pretty picture of the coral reefs in the Florida Keys, scientists consider critical data for mapping coral-reef degradation caused by pollution. A picture really can be worth a thousand words.
A few years after my first encounter with NASA’s remote-sensing studies, I earned a Master’s degree in geography from the University of Maryland, and this led me to my current job. For eight years I have been working at NASA as a contractor, of which the past three years have been as an employee of a firm called Stinger Ghaffarian Technologies (SGT). At the GSFC, roughly 50% of the workforce are contractors and there are many great relationships between the civil servants and the contract employees. SGT is one of those contracting companies and it has really provided me with the support and freedom to grow.
When I was an intern at the GSFC, I was making pictures and posters of satellite imagery purely for aesthetics, but now I make them to portray my research and its results. During my career, I have worked on numerous Earth-science projects, from studying vegetation regrowth following large-scale fires in Yellowstone National Park, to creating global datasets, and I am currently helping my NASA colleagues test a prototype method of estimating global carbon stocks at hectare-scale (10,000 m2) resolution. By integrating many sources of information, such as land-cover data from the Landsat satellite, tree-canopy information from lidar sources (pulses of light directed towards the ground and returned to map surface heights), and radar- and ground-collected field data, we are developing the most accurate way to date of predicting global carbon stocks and fluxes of forests. Since understanding the global carbon cycle is essential for predicting climate change, having this information about biomass flux is crucial.
On a daily basis, I am applying principles of physics and mathematics to analyse information from satellite imagery. One thing you quickly learn in this field is that while remotely sensed Earth imagery is visually impressive, behind every pretty picture there is information in the form of pixel values, and these have to be interpreted. For example, the data are often a stream of values from zero to 255 (calibrated to the reflected and emitted energy received at the satellite, in the case of Landsat), so I have to be able to interpret how the changes in those values relate to changes in Earth’s land cover. I also use an advanced algorithm to help me find the best satellite images to use in analysing the way that land cover has changed. In a position such as mine, there are two things that you need: the curiosity to ask questions; and the willingness and skills to find the answer to those questions. Without my background in physics, that would not be possible.
I often get asked how a person gets a job at NASA. The first thing I usually tell them is that it is not easy. NASA is continually ranked as one the best federal institutions to work at thanks to its culture and benefits, so there is not a high turnover of staff – people tend to stay here for a long time, whether they are contractors or civil servants. So, on top of being highly qualified in whatever field you are in, I recommend that would-be applicants try to get a “foot in the door” in one way or another. For me, this was an internship, but many people get hired because they made a good impression at a conference or have been recommended by another employee. As my experience shows, physics can lead to a fascinating career, and may even change your perspective of the Earth.
Shannon Franks is a remote-sensing scientist who works as an SGT contractor at NASA’s Goddard Space Flight Center in Maryland.
Source: Shannon Franks, written for Physics World
+ “Enjoy a new perspective of the Earth”, Physics World [external link]
The world has lost 561 square miles (1,453 square kilometers) of salt marshes over the past 20 years.