Two important meetings of scientists took center stage for the Cassini team this month. COSPAR, the Committee on Space Research, came to Pasadena on July 15. This week-long scientific assembly convenes once every two years, with the stated mission “to promote at an international level scientific research in space, with emphasis on the exchange of results, information and opinions, and to provide a forum, open to all scientists, for the discussion of problems that may affect scientific space research.”
The following week was dedicated to PSG #75, the Cassini Project Science Group meeting at JPL. This was the Project's final PSG. Scientists will of course continue to meet to analyze and discuss the results of Cassini's scientific observations for decades to come, but they will not be PSGs per se.
Wednesday June 27
A conceptual model was published today, by the European Space Agency, which postulates a mechanism for producing the plume of Saturn's moon Enceladus that is rich in organic molecules: https://saturn.jpl.nasa.gov/news/3148/complex-organics-bubble-up-from-ocean-world-enceladus.
Sunday July 1
Today (Universal Time) marks 14 years since Cassini's Saturn Orbit Insertion.
A classic Cassini image of Saturn's small, active moon (and ocean world) Enceladus was NASA's selection for the Astronomy Picture of the Day today: https://apod.nasa.gov/apod/ap180701.html.
Monday July 9
Cassini’s close-up Grand Finale orbits revealed a surprisingly powerful and dynamic interaction of plasma waves moving from Saturn to its rings and its moon Enceladus. Rendered into audio, one typical observation by the Radio and Plasma Wave Science instrument (RPWS) is presented here: https://saturn.jpl.nasa.gov/news/3150/listen-sound-of-electromagnetic-energy-moving-between-saturn-enceladus.
Saturn is not to be ignored in this remarkable photo that was selected as NASA's Astronomy Picture of the Day. Our favorite ring-world is the brightest object off towards the two o'clock position from Mars: https://apod.nasa.gov/apod/ap180709.html.
Thursday July 12
The Academy of Television Arts & Sciences nominated JPL for "Outstanding Original Interactive Program 2018" based on its coverage of the Cassini mission's Grand Finale at Saturn, including news, web, education, television and social media efforts. Further information is here: https://saturn.jpl.nasa.gov/news/3151/nasas-cassini-coverage-lands-an-emmy-nomination.
Saturday July 14
The full week of COSPAR meetings began today. Cassini scientists discussed their findings in successive sessions on multiple days. It was obvious during the meetings that the momentous discovery of subsurface global oceans on Saturn's moons Titan and Enceladus has brought these two places into the company of known "ocean worlds" in our solar system. The topic of ocean worlds was prominent during this COSPAR assembly, in sessions describing newly acquired science, and also in proposing many ways to investigate these, and other, potential habitats for extant or previous independent life in our solar system.
Sunday July 15
These evenings are especially good for looking at planets. Saturn is very well placed in the evening sky for viewing. Its largest moon Titan shares the view in nearly any sort of telescope, and Saturn's rings are tilted wide-open towards Earth, making for an unforgettable sight. Look for the ringed planet in the sky about mid-way between bright Mars and Jupiter; Venus is the unmistakably bright object farther to the west.
Monday July 16
The image of Saturn featured today is remarkable in many ways. Taken in 2010 when the sunlight was cutting nearly edge-on to the rings, they cast a thin shadow onto the planet's cloud tops. The F ring in particular, seen as the bright narrow strand outside the main rings, all but disappears where part of its arc passes in front of the planet. This attests to that ring's fine, "freshly ground" granularity. The same can be seen with the fine material in the Cassini Division between the A ring and the B ring. Finally, the view of the terminator between Saturn's dayside and nightside is uniquely visible in spacecraft images, since Saturn's dayside is prominent in the view from Earth. The image is worth clicking on to enlarge: https://saturn.jpl.nasa.gov/resources/7845/planet-six.
Wednesday July 18
COSPAR offered a public presentation on "Searching for life in the Solar System and Beyond" tonight at the Pasadena Civic Auditorium. It featured a moderated panel of scientists from Caltech and MIT. Some of Cassini's discoveries at Saturn naturally made it into the discussions.
A set of images presented on the Cassini website today reveals views from the Visible and Infrared Mapping Spectrometer (VIMS) of the evenly-sunlit surface of Saturn's giant moon Titan. The long infrared wavelengths that VIMS was sensitive to can easily penetrate Titan's hazy, cloudy, thick atmosphere, which completely blocks any visible-light view of this world: https://saturn.jpl.nasa.gov/resources/7846/seeing-titan-with-infrared-eyes.
Monday July 23
Cassini's week-long PSG meeting #75 began today at JPL.
The Realtime Operations manager gave a talk about Cassini's innovative mission to 700 employees of the Walt Disney Company today.
Friday July 27
Cassini's PSG #75, the Project's final one, was a tremendous success. New science results from the Grand Finale orbits, and other new results, were discussed. These included the large, complex organic molecules inferred in particles originating inside Saturn's small, active moon Enceladus. Project closeout activities were also discussed.
A special preview of the movie, "In Saturn’s Rings" was provided by filmmaker Stephen Van Vuuren, for viewing by the PSG attendees. The movie used numerous images that had been taken by Cassini during its 13-year tour of Saturn.
While this was the final PSG per se, other Cassini-related science meetings will continue; the next one will be The Final Cassini Science Symposium, to be hosted by the University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP).
Monday July 30
Today's featured image captured five of Saturn's moons from an equatorial point of view seven years ago: https://saturn.jpl.nasa.gov/resources/7848/group-portrait
Tuesday July 31
Behind the scenes on the Cassini-Huygens Mission, today was the last full day for the Cassini ground system operations net, aka the opsnet.
Since 1996, all during Cassini's assembly, test, launch, cruise, and Saturn-tour phases, the ground-system operations local-area network has been providing continuous, secure, and reliably uninterrupted digital communications among all the interconnected scientists' and engineers' computers at JPL.
Thanks to its exchanges with the Deep Space Network (DSN), the opsnet conveyed all the telemetry bits from the spacecraft -- unique science data from Cassini's instruments, plus repetitive engineering measurement like temperatures, voltages, and all. It carried all the commands from the scientists and engineers as they iterated and negotiated and built them, and it conducted them as they were about to be transmitted to the spacecraft. The opsnet conveyed monitor data telling every detail of the DSN's own operations, and it carried "QQC," the quality, quantity and continuity data that constantly reported on how the whole Cassini ground system was operating. All the important data that the opsnet served during its lifetime has now been archived and stored for public scientific use into the future.
This internal network shutdown does not in any way affect the Cassini public web presence, currently at: http://saturn.jpl.nasa.gov