NASA’s Cassini’s spacecraft is entering its final month of functionality. Since July 1, 2004, 02:48 UTC, the satellite has provided thousands of photos of the second-largest planet, Saturn. When the spacecraft runs out of fuel, Cassini will enter Saturn’s rings and become space trash.
The nuclear-powered spacecraft has been valuable for studying the planet. It has taken close-up pictures of 13 years of the massive gaseous planet, its remarkable rings, and its enigmatic moons. Because of Cassini, scientists have learned a lot about Titan, a moon with an atmosphere, and icy Enceladus, with a subsurface ocean that could conceivably harbor microbial life.
Scientists don’t want to contaminate the planet, nor any moon, because of the consequences it would have on those hidden oceans. NASA will direct Cassini onto a crash course with Saturn.
Grand finale: Cassini’s final mission phase
According to NASA, the spacecraft will orbit five last times around Saturn’s upper atmosphere. The first pass over Saturn was on Monday, Aug 14, at 12:22 a.m.
The cameras at that point reached a distance of just 16 miles (25 km). But as far as it could get, it would be able to take better pictures, and better measurements of the atmosphere, using Cassini’s Ion and Neutral Mass Spectrometer (INMS). The closest point Cassini will approach into its course will be between 1,010 and 1,060 miles (1,630 and 1,710 kilometers) above Saturn’s cloud tops.
Saturn’s auroras, temperature, and the vortexes at the planet’s poles will also be observed and detailed with high-resolution Cassini’s instruments.
According to NASA’s scientists, Cassini will require its small rocket thrusters to maintain its stability when entering to Saturn’s clouds, the same it used as it orbited Titan atmosphere.
“Cassini’s Titan flybys prepared us for these rapid passes through Saturn’s upper atmosphere,” said Earl Maize, Cassini project manager at NASA’s Jet Propulsion Laboratory (JPL) in California. “Thanks to our past experience, the team is confident that we understand how the spacecraft will behave at the atmospheric densities our models predict.”
The spacecraft will be able to raise the altitude of the closest approach on next passes due to its referred “pop-up maneuver,” likely by about 120 miles (200 kilometers). But if the atmosphere is less dense than it’s thought, scientists won’t need it during the first three passes. They will use the “pop-down” option to lower the closest approach altitude in the last two orbits, also likely by about 120 miles (200 kilometers).
“As it makes these five dips into Saturn, followed by its final plunge, Cassini will become the first Saturn atmospheric probe,” said Linda Spilker, Cassini project scientist at JPL. “It’s long been a goal in planetary exploration to send a dedicated probe into the atmosphere of Saturn, and we’re laying the groundwork for future exploration with this first foray.”
After Jupiter, Saturn is considered the second-largest planet in the Solar System. The radius of this gas giant is about nine times compared to the Earth’s, and its volume is over 95 times greater.