In 2004 the Cassini spacecraft began its mission orbiting Saturn. The spacecraft has amassed a number of discoveries including finding jets of water erupting from the surface of Enceladus and several previously undiscovered moons of Saturn. Now, running low on fuel, the Cassini prepares to complete its final set of orders that will see it plunge into the planet to destroy itself. The thinking behind the spacecraft’s suicidal demise is that it will avoid the Cassini crashing into what may later turn out to be a habitable moon.
Development and Launch
The Cassini was named after Giovannu Cassini, a 17th-century astronomer and the first recorded person to observe moons around saturn. The spacecraft was the first to be built specifically to observe Saturn. Construction of Cassini started in 1994 and cost a staggering $3.3 billion or what would roughly amount to $5 billion today.
Following its launch in 1997, the spacecraft took what one may consider a little bit of a detour. To get the 5,700 kilogram craft up to speed, it’s flight plan included two flybys of Venus, 1 of Earth and a fourth flyby around Jupiter. The flybys were designed to take advantage of each planet’s gravity to give Cassini a boost. Almost 7 years later on July 1, 2004, the spacecraft settled into an orbit around its target, Saturn.
Over its 13 year mission, Cassini observed a number of amazing events. In 2015, it found evidence of liquid water on Enceladus after observing the icy moon shooting jets of water into the air. Cassini was then directed to complete a number of flybys that scientists used to collect more information regarding the gas and dust in the water plumes. Although the cause of the jets was initially thought to be Saturn’s gravity warping the moon, scientists have now postulated that internal heat within the moon may also contribute to the eruptions.
One of the more exciting discoveries was that of a number of additional moons that had, since then gone unobserved. Two new moons (Methone and Pallene) were discovered almost immediately after Cassini arrived. Before that same year had come to a close, it had discovered a third new moon, Polydeuces bringing Saturn’s total number of moons to 62.
Other discoveries included the discovery and study of a giant methane lake on Saturn’s largest moon, Titan, a 50-mile landslide on Iapetus, and a giant outer ring 8 million miles away from Saturn. In all, the information gathered by the Cassini will fuel scientific discussion and discovery for decades to come.
Cassini’s Final Days
The Cassini mission was only planned to last four years and would have come to its conclusion in 2008. However, the mission was extended multiple times and has more than tripled its projected lifespan. The final mission extension (Cassini Solstice Mission) began in 2016 and included maneuvers that would provide close-up observations of Saturn’s rings. The maneuvers included weekly orbits of Saturn’s Poles between November 30, 2016 and April 22, 2017 to study the particle, gases and structures that made up the planet’s rings, and a final flyby of Titan on April 22, 2017.
The final maneuver of the Cassini Solstice Mission will see the spacecraft make a “suicidal” plunge into the ringed planet on September 15, 2017. During its descent, Cassini will take measurements of the makeup of Saturn’s atmosphere and potentially its inner core. It will continue to send these measurements back to earth for as long as it can before being destroyed.