RocketSTEM Issue #7 - May 2014 | Page 28

Titan’s surface, remember that with thick hazy atmosphere, you cannot actually see the surface from above. Recently Cassini measured the depth of Titan’s second largest sea, Ligeia Mare, to be about 560 feet in depth. Since Titan’s water bodies are mostly Methane plane,” said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “You cannot see the polar regions very well from an equatorial orbit. Observing the planet from different vantage points reveals more about the cloud layers that cover the entirety of the planet.” Cassini changes its orbital inclination for such an observing campaign only once every few years. Because the spacecraft change the angle of its orbit, the inclined trajectories require attentive oversight from navigators. The path requires careful planning years in advance and sticking very precisely to the planned itinerary to ensure enough propellant is available for the spacecraft to reach future planned orbits and encounters. In comparison to hurricanes on Earth, the one on Saturn is gigantic with the eye of the storm being roughly 50 times larger than the eye of a hurricane on Earth at approximately 1,250 miles across. Wind speeds at the outer edge of the storm are around 340 MPH. Unlike hurricanes on Earth, this storm does not migrate; it is stuck in what is essentially a stationary - through the smoggy atmosphere of Titan, the bottom. Cassini also discovered a huge hurricane swirling around Saturn’s north pole just last year. Even though Cassini has been in orbit since 2004, the polar region was dark due to the northern hemisphere being in winter. The composite infrared spectrometer and the visual and infrared mapping spectrometer detected a massive vortex quite some time ago. However it could not be seen until recently with winter ending in the northern hemisphere. “Such a stunning and mesmerizing view of the hurricanelike storm at the north pole is only possible because Cassini is on a sportier course, with orbits tilted to loop the spacecraft above and below Saturn’s equatorial 26 26 tend to drift northward because of the forces acting on the fast swirls of wind as the planet rotates. The one on Saturn is already as far north as it can be. The end result is a strong swirling storm, with no place to go. “The polar hurricane has nowhere else to go, and that’s likely why it’s stuck at the pole,” said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Virginia. Unrelated to the hurricane in the polar region, a massive thunder and Lightning storm was detected Credit: NASA/JPL/Space Science Institute in Saturn’s northern hemisphere. After forming, the turbulent head of the storm moved west and spawned a clockwise rotating vortex that followed the same path but more slowly. In a matter of just a few months the storm encircled the entire planet, stretching some 190,000 miles, with thunder and www.RocketSTEM .org