50 Years of Robotic Planetary Exploration: Julie Castillo-Rogez, Planetary Geophysicist at the Jet Propulsion Laboratory (JPL)
8 Feb 2013
What do you think are the most significant events that have occurred in the past fifty years of robotic planetary exploration? Why?
The arrival of Voyager 2 at Saturn and then Uranus and Neptune had the most important impact on me. I was a teenager at the time, and while I had become interested in astronomy at an early age, the Voyager observations certainly determined my interest in pursuing a career in planetary science.
I reminisce particularly about the Neptune flyby.
Voyager revealed such an amazing planet: Neptune was so blue and had large clouds. I remember making paintings of some of these pictures.
The wealth of images that we obtained from the satellites of the outer planets continue to amaze me.
It is interesting to look at the Voyager pictures, especially now that Galileo and Cassini-Huygens have also explored -- in more detail -- the Jovian and Saturnian systems. We have learned so much over the past fifteen years about the icy satellites in these two systems.
Also, the images returned by Voyager 2 of Uranus and Neptune are the only detailed observations available for these planets and their systems. They are thus unique -- literally! However, I am hopeful that we will see a mission to the Uranian and Neptunian systems if not in this decade, then the next one.
In your field of work, what are some examples of the great achievements and discoveries in planetary science and robotic exploration throughout the past 50 years?
Cassini's extensive tour of the Saturnian system is a paramount example of achievement.
Through almost a decade of continuous observations, Cassini has provided us with a greater understanding of how giant planet systems work, i.e., how the planet and its fields interact with and shape the satellites, the genetic relationship between satellites and rings, the exchange of material across the system, etc.
This holistic view of the Saturnian system has revolutionized the way we think about planetary origin, with implications that go beyond our own solar system. We can leverage our knowledge of the Saturnian system to understand how exoplanetary systems get organized and evolve as a consequence of mutual interactions.
The Cassini-Huygens mission was a particularly well-thought-out mission with a combination of all types of instruments. The Cassini orbiter has been operating in the Saturnian system without any major failures since 2004.
The successful landing of the Huygens probe on Titan was also spectacular.
Cassini also discovered two astrobiological targets in Enceladus and Titan.
Incidentally, the Cassini-Huygens mission was also a great success on the political front, with 18 countries working together towards achieving the same goal.
Another great achievement is the progress in the development of ion propulsion.
We are going through a big change in the way missions are designed thanks to the increasing performance of this technology. The Dawn mission is a fantastic example of ion propulsion and how it facilitates having multiple destinations. Ion propulsion also enables extensive coverage of planetary bodies through "rendezvous."
Dawn's visit to Vesta was impressive, but it is the prospect of its rendezvous with asteroid Ceres, Vesta's water-rich counterpart, that will greatly increase the overall science return of this mission by enabling the scientists to compare these two protoplanets.