An Alchemist’s Collection of Chemical Goodies

Todd J. Barber, Cassini lead propulsion engineer

The Cassini spacecraft began a busy month of May celebrating Cinco de Mayo up close and personal with a familiar target, Titan. From radio wavelengths to the ultraviolet, our tireless explorer and its instruments investigated Saturn’s largest moon across the electromagnetic spectrum. This Titan-54 flyby was relatively high, at 3,244 kilometers (2,016 miles) in altitude, allowing more remote sensing observations. Even before closest approach, our infrared spectrometer peered into the Titan atmosphere, studying profiles of temperature and suspended, tiny solid or liquid particles called aerosols. Our other infrared instrument examined clouds on Titan, and our visible light camera (not to be outdone) obtained fine-resolution imagery towards Titan’s south pole. In addition, an ultraviolet spectrograph studied an alchemist’s collection of chemical goodies in Titan’s atmosphere, including nitrogen, monatomic hydrogen, hydrocarbons, and aerosols as well. Lest remote sensing instruments have all the fun, our Radio and Plasma Wave Science (RPWS) instrument also got down to business, looking for Titan lightning, studying Saturn’s magnetosphere as it reacts with Titan, and examining Titan’s ionosphere with its thermal plasmas.

On the engineering front, May had a terrific start, with the cancellation of OTM-192 and OTM-194, along with the decision to perform Reaction Wheel Assembly (RWA) friction tests less frequently, thus saving precious hydrazine propellant for a further mission extension. In fact, we were able to cut the frequency of these check-out maneuvers in half! Also, for you fans of Greek mythology (and a preponderance of vowels), the IAU (International Astronomical Union) approved the name “Aegaeon” for a Cassini-discovered satellite of Saturn. Despite its small size of roughly 0.3 miles (0.5 km), it resides within Saturn’s intriguing G-ring and, in fact, might be the source of the ring material itself. Mid-May featured Saturn observations of oxygen and hydrogen by our infrared and ultraviolet spectrometers, with OTM195 and OTM196 as bookends. If this period seems busier than usual, your instincts are good! There’s nothing like the frenetic pace of sixteen-day orbits to keep us hopping!

Despite a full plate for Cassini and its flight team, many members of the project volunteered for the annual JPL Open House the first weekend of May. Over 30,000 visitors reveled in the best the lab had to offer, and it was again an honor and privilege meeting so many excited and intelligent members of the public. Your support makes these journeys of discovery possible, and I thank you for joining us in this historic voyage to Saturn and its moons.