On June 30, 2004, the Cassini-Huygens mission performed its SOI or Saturn Orbit Insertion burn to enter orbit around this enigmatic gas giant. This day marked the beginning of over 13 years of continuous operations in the Saturnian system. Online you may see that Cassini arrived on either June 30th or July 1st, depending on the source, that’s due to its arrival late in the evening and time zones. (The Jet Propulsion Laboratory is located in California, so when Cassini arrived at Saturn at 9:12 p.m. Pacific time, it was June 30th.)
On October 15, 1997, Cassini launched on a Titan IV B rocket with a Centaur upper stage. The Cassini orbiter and Huygens probe weighed a combined 13,298 pounds at launch, with nearly 8,000 pounds of fuel. The orbiter was 22 feet high by 13.1 feet wide and operated from power generated by radioisotope thermoelectric generators. These RTGs powered the communications for the orbiter and the dozen or so science instruments onboard.
Cassini arrived at Saturn after a 6 year, 261-day cruise that included gravity assists at Venus (twice), Earth, and Jupiter. That’s one long road trip!
One of the coolest parts of this mission was when the Huygens lander touched down on Titan, the second-largest moon in our solar system. Here’s a fun fact, Titan is larger than the planet Mercury.
The Huygens lander explored Titan due to the moon’s unique properties. According to NASA, “Titan is the only moon in our solar system that has clouds and a dense atmosphere, mostly nitrogen and methane. It is also the only other place in the solar system to have an earth-like cycle of liquids flowing across its surface.” Much of what we now know about Titan is thanks to Cassini and Huygens.
The Huygens lander was developed by the European Space Agency and was part of the overall Cassini Huygens mission between NASA and ESA. While the scientific knowledge we gained from the lander is incredible, I think the international collaboration and cooperation needed to pull off an interplanetary landing is just as important.
“There is no strife, no prejudice, no national conflict in outer space as yet. Its hazards are hostile to us all. Its conquest deserves the best of all mankind, and its opportunity for peaceful cooperation many never come again.” John F. Kennedy, Rice University Speech.
Cassini-Huygens represents some of the best of what we can achieve in space. Peaceful cooperation between sovereign nations working towards a common goal of expanding scientific knowledge. As much as science will be part of Cassini’s legacy, the partnership between nations for this mission will be just as important fifty or one hundred years from now. The policy of cooperation on massive scientific undertakings like Cassini bodes well for future missions to other worlds.
Cassini’s prime mission started in 2004 and went until 2008. There were multiple mission extensions; the first went from 2008 to 2010 and was called the Equinox mission. A final extension, the Solstice mission, lasted from 2010 until September 2017.
On September 15, 2017, Cassini’s mission came to a close as the spacecraft plunged into Saturn’s atmosphere. I remember watching the NASA TV coverage and countdown that morning. As a kid, I saw news coverage of the launch, as a high schooler I saw the first images of the Huygens probe landing on Titan, and as an adult, I saw the end of a mission I had grown up with.
Photographs- NASA/JPL/Caltech and Kevin Gill