Liftoff of Cassini!
Cassini’s mission may be over, but scientists are still pouring over the data gathered during this mission.
The Cassini spacecraft launched on October 15, 1997. Pictured here is the Titan IV B rocket that started Cassini on its journey to Saturn.
Author’s note- Headline and minor updates were done on the 23rd anniversary of Cassini’s launch.
The Cassini mission holds the distinction of being the only scientific payload to launch on a Titan IV rocket, all other launches with that rocket had been for the military or intelligence agencies.
The Titan IV used hypergolic propellant, which was an excellent fuel for ICBM’s, since the propellants can be stored as liquids at room temperature, removing the need for the time-consuming loading of cryogenic fuel and oxidizer.
The Titan family of rockets had an impressive lineage, from the Gemini program Titan II’s to the final launches of the Titan IV in 2005. The Titan IV had a distinct look and is one of my favorite rockets, which is why I wanted to give a brief history of the rocket that launched one of NASA’s coolest missions.
Back to the launch-
At the start of the mission, the Cassini orbiter and Huygens probe weighed a combined 13,298 pounds, with nearly 8,000 pounds of that being fuel. The spacecraft was 22 feet high by 13.1 feet wide and had power generated by radioisotope thermoelectric generators. These RTGs powered the communications for the orbiter, as well as the science instruments onboard.
After launching from Earth, the spacecraft performed numerous gravity assist maneuvers, twice at Venus, once at Earth, and finally once at Jupiter.
Cassini passed just 727 miles above Earth, and according to a JPL blog post from 1999, “the spacecraft may be visible from small islands in that area, such as Pitcairn Island or Easter Island. Two successful flybys of Venus, next week’s flyby of Earth, and a flyby of Jupiter in December 2000 all give Cassini the additional speed it needs to reach Saturn in 2004.”
The spacecraft arrived at Saturn after a six-year, 261-day cruise and started investigating the planet and its moons. Cassini’s prime mission began in 2004 and went until 2008. The first mission extension was from 2008 to 2010, the Equinox mission. The final extension, the Solstice mission, lasted from 2010 until September of 2017.
What’s in store now that Cassini’s mission has ended?
Studying Saturn and its moons have yielded an incredible amount of data, some of which are still being analyzed. This NASA article details some of the exciting findings showing complex organics held in the rain in Saturn’s clouds. These observations were made possible by the unique orbits of the grand finale phase of the mission. Bringing the spacecraft in for a closer look also sheds new light on Saturn’s rings and magnetic field. Read the entire article here.
The Cassini mission also helped us explore exotic worlds like Titan. Check out one of my latest podcast episodes where we dive into ocean worlds with Melissa Ugelow, a scientist studying Titan.
Cassini sent back over 500 gigabytes of scientific data to scientists and civilians during its 13-year mission at the Saturnian system. This striking annotated image below is a perfect example of what Cassini brought back to us. Everyone you have ever known is in a dot that’s about the size of one pixel in this image. Cassini brought back information about other planets while showing us our place in the universe, that’s one incredible legacy.