The highly ambitious Cassini mission was launched on the October 15th of 1997. After seven years, the spacecraft entered Saturn’s orbit where it has made some incredible discoveries. The spacecraft discovered liquid hydrocarbon lakes on Titan, Saturn’s largest moon. It also found spying plumes of water ice and particles jetting from a subsurface ocean within another moon, Enceladus.
A panel of Cassini scientists revealed that the spacecraft is almost ending its journey. Cassini moved closer to Saturn in November in preparation to end its mission. On the 22nd of April, engineers are expected to use Titan’s gravity to tweak Cassini’s orbit for the last time. The move is a fuel-saving maneuver that has been used throughout the mission to change the craft’s velocity by slingshotting it through the moon’s gravitational field.
The move will send Cassini rising between the rings and the planet, a route never taken by a spacecraft before. It will circle the planet in this manner nearly two dozen times before it spirals into its gassy atmosphere in a dramatic final descent in September.
Cassini’s path has already been modeled by researchers. It is expected to barrel at more than 110,000 kilometers per hour into a relatively narrow 1,200-mile gap. Earl Maize, Cassini’s project manager at JP, revealed that the maneuver is very risky, adding that a piece of sand at that velocity can take out the instruments.
Cassini will capture images and measure the rings’ mass to offer insight into their possible origin, age and particle composition. Cassini Project Scientist Linda Spilker at JPL revealed that Saturn’s rings are 99 percent water ice but the team is not certain about the other 1 percent.
The capsule will also capture the best-ever views of both giant hurricanes that swirl at the planet's poles. Especially the curiously shaped hexagonal jet stream at the north pole. It will also measure the abundances of hydrogen, helium and other atmospheric gases as well as study the polar auroras.
Researchers will also get a first-time sight of the gas-giant planet’s hidden interior by revealing the size of the gas-shrouded rocky core, Cassini will also measure Saturn’s gravitational and magnetic fields.
Jonathan Lunine who is a co-investigator on the Juno mission expressed his enthusiasm in comparing the interior structures of Jupiter and Saturn. Juno mission will be getting the first gravity data for Jupiter, which Lunine will use to compare the interior structures of Jupiter and Saturn.
On September 15th, 2017, the capsule will be in its final drive between Saturn’s rings. The path will send it tumbling into Saturn’s atmosphere. The spacecraft will struggle for up to three minutes to keep its antenna pointed toward earth. Cassini will transmit final data before it disintegrates into Saturn.
The self-destructing maneuver serves to eliminate the risk of Cassini accidentally encountering and contaminating any of the countless Saturnian moons with biological material from Earth.
SOURCE: https://www.scientificamerican.com/article/cassini-bids-farewell-before-blazing-into-saturn-video/
