Cassini probe prepares for final five trips around Saturn

Aug. 10 (UPI) -- NASA's Cassini probe is set to make its final five orbits around Saturn. The final stage of the probe's "Grand Finale" will see Cassini execute five intimate dives through the gas giant's upper atmosphere.

The first of the five final orbits will commence on Monday, Aug. 14, at 12:22 a.m. EDT. Cassini's final flyby will feature a kamikaze dive into Saturn's atmosphere -- a career-ending plunge.

During its closest approach, Cassini will pass within 1,010 and 1,060 miles of Saturn. Cassini will likely experience resistance from Saturn's dense upper atmosphere, requiring the use of the probe's rocket thrusters to maintain orbital stability. Cassini experienced similar atmospheric resistance during its close approaches to Saturn's moon Titan.

"Cassini's Titan flybys prepared us for these rapid passes through Saturn's upper atmosphere," Earl Maize, Cassini project manager at NASA's Jet Propulsion Laboratory in California, said in a news release Wednesday. "Thanks to our past experience, the team is confident that we understand how the spacecraft will behave at the atmospheric densities our models predict."

NASA engineers will consider Cassini's first upper atmosphere flyby a success if the probe's thrusters engage at 10 to 60 percent of their capacity. If the atmosphere proves thick enough to require the thrusters to work harder, scientists will likely raise the altitude of final four orbits.

If the upper atmosphere is thinner than expected, scientists could also choose to lower the altitude of Cassini's final orbits.

A total of seven instruments, including its ion and neutral mass spectrometer, will be activated during the trip across the tops of Saturn's clouds.

The probe will measure the upper atmosphere's composition and density. Cassini will also observe Saturn's auroras, temperature gradient and polar vortexes. Earlier this year, Cassini collected extensive data as it flew through Saturn's rings.

"As it makes these five dips into Saturn, followed by its final plunge, Cassini will become the first Saturn atmospheric probe," said JPL scientist Linda Spilker. "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."