Cassini is set to take its final plunge into Saturn’s atmosphere on September 15th, returning as much data as possible before it’s vaporized by the heat and pressure. Scientists attached to the project are confident that they will get enough data back during Cassini’s last moments to provide years’ worth of discoveries.
During Cassini’s entry into Saturn’s atmosphere, the final transmission is expected to occur at 3:32:00 AM PDT. Right up until then, it is expected to transmit real-time data that includes:
- Magnetic field measurements to better understand Saturn’s rotation rate
- Direct analysis of Saturn’s atmospheric composition
- Direct analysis of any dust particles in Saturn’s atmosphere
- Direct analysis of Saturn’s ionosphere
Because scientists have never peered into Saturn’s atmosphere on this scale, several instruments could pick up something completely unexpected before giving out altogether. “We hope there will be a lot of Ph.D. theses coming out of this,” Cassini project scientist Linda Spilker joked during a news conference that was aired live on NASA TV.
The final plunge into Saturn’s atmosphere marks the end of over 13 years of discoveries while Cassini was in orbit around Saturn. This included two mission extensions and numerous groundbreaking observations of Saturn’s major moons (Enceladus, Tethys, Dione, Helene, Rhea, Titan, Iapetus, and Phoebe). Interesting discoveries included a better “close-up” understanding of Titan’s surface, which includes lakes of ethane and methane, as well as molecules that could be used for cellular membranes. Encaledus has been found to have free hydrogen, which indicates the presence of boiling water interacting with a possible rocky seabed and increases the odds of finding life on this moon.
One common question on the minds of Cassini’s team members and followers include: What comes next? One proposal for joint exploration by NASA and ESA called the Titan and Encaledus Mission (TandEM/TSSM) has already been scrapped in favor of a mission that will explore Jupiter and its moon, Europa. This mission would have included a Titan orbiter, Titan in-situ aerial platforms, and a Titan probe/lander and could have launched as early as 2020.
Of course, this doesn’t mean that there isn’t interest in following up on fascinating discoveries such as the geysers on Enceladus, which often spew chemicals that could support life. When a panel of scientists attached to Cassini were asked if they would have changed anything if they could, one of them said, “I wouldn’t have changed a … thing.” Another said that if they had known about the geysers on Enceladus, they could have included more sensitive spectrometers so that they could perform better chemical analyses of the material being spewed by those geysers, which was one of the more interesting discoveries made using data returned by Cassini. So it becomes a matter of how fast a follow-up to the highly successful Cassini-Huygens mission can be approved by NASA’s bureaucracy, receive funding, and then be built and launched.
Project scientist Linda Spilker summed up the entirety of Cassini this way: “We had a rare opportunity and we seized it.”
Now NASA has an opportunity to follow through on Cassini’s success with future missions while the going is good. With the upswing of public interest generated by the Cassini-Huygens mission and its impressive discoveries, however, it will probably just be a matter of time before a follow-up mission is approved. Such a mission could focus on studying the moons of Saturn that are gaining a reputation for possibly being friendly toward life and could even probe under the frozen surface of Enceladus to explore a hypothetical ecosystem that could thrive so far from the sun.