2023 G. K. Gilbert Award

Presented to Candice Joy Hansen-Koharcheck

Candice Joy Hansen-Koharcheck

Candice Joy Hansen-Koharcheck
Planetary Science Institute


Citation by Emily Martin

One of the pillars of planetary geology is robotic exploration. To accomplish great feats of science through robotic spacecraft, one must be an astronomer, physicist, engineer, modeler, observationalist, explorer, politician, accountant, and a geologist. To honor Dr. Candy Hansen as the 2023 G. K. Gilbert Awardee for the Planetary Geology Division (PGD), I will attempt to summarize Dr. Hansen’s accomplishments to date with all the credit they are due.

Dr. Candy Hansen’s distinguished career in robotic exploration began when she joined the Voyager science team straight out of college. It was here, as a graduate student, that she began making substantial contributions to our understanding of the role of volatiles in active geologic processes. Her work on Voyager includes a pivotal paper describing the discovery of plumes on Neptune’s moon Triton. Candy was a member of the Cassini UVIS team at Saturn where she contributed to a long list of papers characterizing the composition, structure, and dynamics of Enceladus’s plume. She has led the science development and operations of the JunoCam. Initially designed to be a camera for public engagement, JunoCam quickly became a valuable scientific instrument, returning unprecedented images of Jupiter, and the Galilean moons.

As the Deputy-PI for the High-Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter, Candy focused her research on smaller-scale seasonal changes which has significantly contributed to the shifting perspective of Mars being a quiescent to a currently active planet. In addition to HiRISE, Candy contributed to the planning and building instruments for the Mars Polar Lander, the ExoMars Trace Gas Orbiter, the Europa Clipper, as well as leading myriad proposals to continue exploring the outer solar system.

Candy has served the planetary community by being a constant advocate for the exploration of the outer solar system. Candy served as the chair of the NASA’s Outer Planets Assessment Group (OPAG), and Chair of the American Astronomical Society’s Division of Planetary Sciences, among many other efforts to advocate for ongoing exploration in the outer reaches of our solar system.

To all of this, Candy is an excellent mentor, scientist, and human. Community consensus has lauded Candy as a “straight-talker”, puts “exceptional effort into encouragement and development of the next generation of scientists”, is a “terrific leader in public outreach.” For all of her scientific achievements, leadership in exploration, advocacy, friendship and mentorship, Candy has been selected as this years G. K. Gilbert awardee.


Response by Candice Joy Hansen-Koharcheck

I am incredibly honored to receive the 2023 G. K. Gilbert award. When someone asks what I do for work, it is thrilling to say "I explore our solar system", a passion, never simply a job. I am thankful to Emily Martin for nominating me for this award and to my colleagues for letters of support.

When I started working with the Voyager imaging team just before launch, the space program was young enough that the old experienced people were in their 30's, and the 20-somethings had important responsibilities. This has led me to appreciate and promote the careers and ideas of the younger generation in our field.

Starting graduate school at UCLA, I was working as an engineer at JPL. I am thankful to my Ph.D. advisor, Dave Paige, for moving me beyond that mindset and teaching me how to be a scientist. His most important advice, when I received my Ph.D., was that this was my license to do science, permission to branch out from my dissertation.

In this field you have to be prepared to be adaptable and ready to learn new things. When Cassini was on its way to Saturn I was working with the Cassini Ultraviolet Imaging Spectrograph (UVIS). Knowing nothing about uv spectroscopy I vowed to learn all that I could from the UVIS team, which paid off immensely when we discovered the water vapor plume spewing from the polar fissures of Enceladus.

This is a field with no guarantees of success, such as our loss of Mars Polar Lander (MPL), but the journey of spacecraft, mission and science design was worth every year and even knowing the outcome I would repeat that experience, doing something I love with people I respect. The search for a good landing site for MPL based on Mars Global Surveyor images led to my fascination with seasonal processes on Mars and the other-worldly terrain created by the sublimation of CO2 ice every spring.

Seasonal processes on Mars are my current focus - what do the fans tell us about the jets emerging every year? Is the behavior different in years with dust storms? In the north polar region seasonal activity is on the dunes of the north polar erg (I had to learn about dunes!). I am thankful to Alfred McEwen for inviting me to join the HiRISE proposal team, and being a part of the team for over 20 years as we continue to get great data from HiRISE.

The thread running through the diverse work I've done, scattered across the solar system, is plumes. In the beginning, when Voyager flew by Io, we saw eruptions on another body for the first time. At Triton, shocking on a body with a surface temperature of ~38K, we found what we believed at the time were solar-driven jets. Now, working on seasonal processes on Mars and studying the solar-driven annual jets there, we ask is it still the right model for Triton? And what might we find at Europa?