Last week, the NASA Cassini spacecraft performed a flyby around Enceladus, one of Saturn's most interesting moons. The mission was not an active one in the strictest sense of the word, but rather aimed at measuring the space rock's gravitational pull. This was done by not activating the probe's instruments. The only thing mission managers did during the 26-hour flyby was to look at how the orbit Cassini took shifted slightly on account of the moon's gravitational pull. The changes became visible by looking at telemetry data accurately pinpointing the location of the spacecraft within the solar system.
The datasets collected on this occasion have already been relayed to mission controllers at the NASA Jet Propulsion Laboratory
(JPL), in Pasadena, California, who manage the Cassini mission. In addition to new data about Enceladus' gravity, researchers will also be able to use the newly-acquired information to decipher several riddles related to the moon's interior composition, as well as its structure. The thing that puzzles astronomers most about this space object is that fact that landscape features at its south pole at times emit plumes of water and ice particles.
Experts have hypothesized that these emissions are caused by active melting processes going on underneath the surface, in which blobs of cooler ice descend towards the core, while heated ice lifts towards the surface. However, until now, insufficient data were available to test this theory. With the new information, assessing the accuracy of these predictions may become possible, investigators hope. The flight took Cassini just 100 kilometers (60 miles) above the south polar regions. The point of closest approach was reached in the late afternoon of April 27 (PST) or just after midnight April 28 UTC.
“Detecting any wiggle will help scientists understand what is under the famous "tiger stripe" fractures that spew water vapor and organic particles from the south polar region. Is it an ocean, a pond or a great salt lake? The experiment will also help scientists find out if the sub-surface south polar region resembles a lava lamp. Scientists have hypothesized that a bubble of warmer ice periodically moves up to the crust and repaves it, explaining the quirky heat behavior and intriguing surface features,” the JPL team said in a statement before the flyby.