Growing up in India, Susan Thomas saw many thunderstorms. Like most children, she was fascinated by lightning. At school, she experimented with light, marveling at the way it split into different colors when passed through a prism. Her curiosity about optics – the scientific study of light – only grew as she studied science in high school.

Optics and physics were the focus of Thomas’ studies while she completed B.S. and M.S. in Kerala, India. She then moved to the United States and decided to begin a master’s program in Computer Science, as she had not done much work with computers during her studies in India and wanted to learn more.

Shortly after graduating, Thomas was offered a job at NASA Langley Research Center to work on a project called the Earth Radiation Budget Experiment (ERBE). ERBE was the predecessor to CERES, and it had three instruments on-orbit at the time. “I had remarkable mentors at the early part of my career,” Thomas recalls. “They took the time and effort to make me learn and understand the project, which helped me on future work.”
As the lead instrument scientist on the CERES experiment, Thomas now uses light – both visible light and radiation – to learn more about how the Earth reflects sunlight and emits its own radiation. The CERES, short for Clouds and the Earth’s Radiant Energy System, experiment includes six different instruments flown on four NASA satellites. Scientists are using the data CERES instruments collect to better understand the role clouds and the energy cycle have in climate change.

Thomas’ work on CERES began as part of the instrument development team where she participated in the testing of instruments before they were launched on a satellite. Once in-orbit, Thomas and her teammates monitor the health of the instrument in different orbital conditions and perform tests to make sure the data collected from the instrument is of the best quality. They send commands to the instruments to collect certain types of data. Thomas also develops software programs and does studies to evaluate possible trends in the measurements.

“My team has the responsibility of ensuring that the CERES instruments are calibrated correctly so that we provide the most accurate data to the scientists, who then use the data to understand the on-going changes in Earth’s atmosphere,” Thomas explains. “I take that responsibility very seriously since the work of others is impacted by it.”

There are many different people from diverse background involved in Earth science, from instrument creation and data collection to interpretation and communication of findings. Thomas emphasizes that both scientists and engineers play important roles in technological advancements. Every day they strive to answer questions and solve problems that lead to knowledge and inventions that change lives. “Every scientific finding—whether it be a new technology or a solution or evaluation of an ongoing problem—has the potential of greatly impacting the world around us,” Thomas reminds us.

That impact is one of the reasons that Thomas considers herself very fortunate to work at NASA. “Growing up in a relatively small town in the south-western part of India, I never dreamed of working at NASA,” Thomas says. “But I had several individuals who encouraged me and taught me to choose a career of my interest – Physics. There were only few girls who ventured into Physics when I was in school. So when the opportunity came my way, I was prepared to take that challenge.” She is particularly thankful for the great teachers who guided her in the world of science, and encourages students to seek out mentors and to learn science with an open and inquisitive mind.