Gust:  Dr. Linda Spilker;  Topics:  The Cassini Grand Finale, all things Saturn and more.  Please direct all comments and questions regarding specific Space Show programs & guest(s) to the Space Show blog which is part of archived program on our website, www.thespaceshow.com.   Comments and questions should be relevant to the specific Space Show program. Written Transcripts of Space Show programs are a violation of our copyright and are not permitted without prior written consent, even if for your own use. We do not permit the commercial use of Space Show programs or any part thereof, nor do we permit editing, YouTube clips, or clips placed on other private channels & websites. Space Show programs can be quoted, but the quote must be cited or referenced using the proper citation format. Contact The Space Show for further information. In addition, please remember that your Amazon purchases can help support The Space Show/OGLF. See www.onegiantleapfoundation.org/amazon.htm.

We welcomed Dr. Linda Spilker back to the program to discuss the final days of the Cassini mission and what we now know about Saturn as a result of Cassini.  During our one segment 96 minute discussion with Dr. Spilker, we started out talking about the Grand Finale mission of the final 22 orbits, how the orbits were planned well ahead of time, the photo sequence along with the final transmission of data back to Earth, how Cassini went in-between the gaps in the rings to eventually burn up in the atmosphere of Saturn.  Dr. Spilker spent some time describing the Grand Finale tour, how it was planned, and then how it was carried out.  She talked about the JPL control room and the similar are at Cal Tech.  We also talked about the mood of those that had worked with Cassini and were there for the Grand Finale tour.  Don’t miss this historic discussion.

Dr. Spilker was asked about Cassini discoveries.  She address two fundamental discoveries and discussed them in detail.  One was Enceladus with water plumes and liquid water oceans under the ice.  She talked about the E ring and the wobble.  The second fundamental discovery she mentioned concerned Titan and the discoveries of the ESA Huygens lander.  The discovery of methane oceans acting as water acts on earth was a huge discovery.  Dr. Spilker talked about Titan and what we learned about it at multiple times during today’s program.

Listener Jack asked how deep the oceans were on Enceladus.  Our guest said they were estimated at tens of kilometers in depth.  She then mentioned drilling through the ice crust and flying through the plumes to learn more.  I asked her if the proposed Europa Clipper mission was similar and she said it was.  We did a brief comparison of possible missions so don’t miss what our guest had to say on this subject as well as Neptune as a target of interest, specifically with its moon Triton. 

Beth in Seattle asked if  planetary missions such as Cassini would benefit from advanced propulsion capable of getting to the destination faster with larger payloads.  Linda thought advanced propulsion would be helpful, mentioned SLS, but was uncertain of the economics.  We then fielded several questions about the rings of Saturn, gaps, contents, thickness and more.  This was a somewhat lengthy discussion with excellent listener questions and great answers from our guest. 

Other topics focused on lessons learned from Cassini and the use of nuclear power with the RTG’s on board (three of them).  At one point a listener asked Linda if the RTG’s could have been used for station keeping so that Cassini would not have run out of fuel.  The short answer was no but listen to the full explanation.  Adrian then sent in a question asking about the gravity boost obtained from Titan and if something similar would exist with Ganymede for a possible gravity boost to benefit the Europa Clipper Mission.  The short answer was yes but listen up for the details. 

As the program was ending, a caller asked about the rate and quantity of data being sent back to Earth.  Dr. Spilker talked about the hi gain antenna and the size of it as being very important.  We also talked DSN limitations for bandwidth.  Related to this in our earlier discussion, our guest told us how they relayed the signals back to Earth re the Grand Finale going through California and then the Australian listening posts. 

In the final minutes of the show, we talked about the value of Cassini which cost about $4 billion.  Our guest mentioned three important areas of value so don’t miss what she said.  Then we took a question about finding exciting discoveries from future Mercury and Venus missions.  In the end, we talked about what we have learned about the rights, a new book that is forthcoming on the rings of Saturn and incredible images NASA has made available at https://saturn.jpl.nasa.gov/  Also at this site you will find details on the Cassini tools Linda mentioned earlier, the Grand Finale images and much more. 

Please post your comments/questions for this show on TSS blog.  You can reach Dr. Spilker through The Space Show or her JPL website page,  https://science.jpl.nasa.gov/people/Spilker.