Todd J. Barber, Cassini lead propulsion engineer
Dr. Lopes is a well-known volcanologist, studying everything from fiery eruptions from every corner of Earth to the volcanic smorgasbord that is Jupiter’s moon Io; now she is investigating potential icy volcanoes (cryovolcanism) on Saturn’s largest moon Titan. Her career has taken her to ever-longer wavelengths in the electromagnetic spectrum, from visible-light data provided by Viking for her PhD thesis to the infrared on Galileo, and now to microwave wavelengths on the Cassini radar team (watch out, TV and radio wavelengths—you may be next!). Even though she described Io as her “first love” and a “volcanologist’s paradise,” she was quick to point out that Titan is extremely interesting because of the diversity of surface processes, including potential cryovolcanism. In fact, her latest paper entitled “Distribution and Interplay of Geologic Processes on Titan from Cassini Radar Data” was just released, a wonderful summary of the current understanding of Titan’s perplexing surface processes. Essentially, the goal of this work was to determine the sequence of events over billions of years of Titan’s history, using geological mapping data from the radar instrument. A familiar method for doing this throughout the solar system is impact cratering assessment, but unfortunately there are scant few craters on Titan’s surface, given its thick nitrogen and methane atmosphere. Despite this, using the principle of superposition (cleverly summarized as “younger things lie on top of older things” by one of Dr. Lopes’ students), she and her colleagues have pieced together a dynamic and fascinating timeline of Titan’s history. Though the details remain to be specified, this work suggests that Titan’s mountains formed first, followed by the plains, craters, and then perhaps cryovolcanic features. The most recent surface features appear to be dunes, channels, and finally lakes—in fact, the last three or four features mentioned may still be active today! What a rich tapestry we’ve found in Earth’s frozen cousin, nearly a billion miles from home!
We closed off our interview discussing Dr. Lopes’ unparalleled work in NASA outreach, where she continues to do as “much outreach as possible” given a busy schedule. I was there in 2005 when she garnered the coveted Carl Sagan Medal from the American Astronomical Society, essentially the top honor for outreach work. Over the years, I’ve attended many of her lectures and I’ve found myself enraptured by her clear explanations of difficult subjects, her passion for her work, and her great sense of humor (not to mention her really cool volcano pictures). Perhaps above all, she is to be commended for her tireless work inspiring the next generation of female scientists and engineers, including a prominent JPL engineer’s daughter who is now pursuing a degree in geophysics. She also mentors countless young students from her native Brazil, showing them the unique appeal of planetary science and that they too can join her on this journey, given hard work in math and science. Thank you, Dr. Lopes, for your work continues to inspire us all.