As destruction nears, Cassini takes a dip in Saturn's atmosphere

After spending 13 years studying Saturn and almost 20 years on its mission, NASA's Cassini orbiter is about to meet its end. Cassini's mission is scheduled to wrap up on September 15, but before it does, NASA is performing a series of final orbits it has dubbed Cassini's "Grand Finale." Those orbits began way back in April, but the orbit Cassini just entered might be the most fascinating one yet.

As of last night, Cassini has started Grand Finale orbit #20, which the third of five orbits where the orbiter will actually dip into the planet's atmosphere. Not only will it enter the atmosphere at one point during the orbit, but this is the deepest Cassini will dip before the end. While this orbit is taking place, Cassini will use its Composite Infrared Spectrometer to map the planet's northern hemisphere and measure temperatures in its upper troposphere.

It'll also use RADAR to study the atmosphere, more specifically using its Ion and Netural Mass Spectrometer to measure the ionic density of the upper atmosphere that surrounds it. It sounds like there's a chance of the atmosphere causing Cassini to rotate, which means that it wouldn't be able to get a precise connection with Earth, but the orbiter's reaction control thrusters will be ready to go to correct any rotation that occurs

This is Cassini's 290th orbit overall, with just three left to go (including this one) before Cassini's mission concludes. Orbit 291 begins on August 30, while orbit 292 will start on September 5, and orbit 293 – otherwise known as "The Final Plunge" – will begin on September 12, wrapping up on September 15 and ending Cassini's 20 year mission.

On September 15, Cassini will begin its final plunge into Saturn itself, communicating with Earth in "nearly real time" as observations are made. During its descent, those thrusters we just mentioned will keep the orbiter stable as long as possible, allowing it to point its antenna at Earth to transmit the data it collects. Eventually, though, Saturn's atmosphere will overpower Cassini's thrusters, causing it to tumble into Saturn and ending the mission once signal is lost.

It's certainly been a exciting ride for Cassini, and with its extended missions now lasting longer than its 4-year prime mission, it'll definitely be one NASA's Jet Propulsion Laboratory will be sad to see end. You can read more about Cassini's final orbits and the end of its mission over at NASA's Grand Finale Orbit guide. It'll be fascinating to see what Cassini collects during its final plunge, so stay tuned.