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Today, we are celebrating a really important milestone in space exploration and planetary science: the anniversary of the launch of Cassini/Huygens in 1997. Wikipedia tells us that Cassini/Huygens is “a joint NASA/ESA/ASI robotic spacecraft mission currently studying the planet Saturn and its many natural satellites.”
We are fortunate to have published a book by a scientist with insider knowledge of this mission, so I turned to PUP author Ralph Lorenz to answer a few questions. Dr. Lorenz has authored two books on the Saturn moon Titan drawing on information and findings from the Cassini/Huygens mission. The first, Lifting Titan’s Veil: Exploring the Giant Moon of Saturn, began the story by describing what we knew of Titan prior to the startling findings of the Cassini/Huygens mission. The second, Titan Unveiled: Saturn’s Mysterious Moon Explored, made full use of the data available to Lorenz and his co-author Jacqueline Mitton, to provide a behind the scenes tale of the mission itself and the startling new discoveries about Titan.
Dr. Lorenz kindly agreed to a brief interview about the Cassini/Huygens mission and what we might expect in the coming years. |
1.) Cassini/Huygens launched with the Huygens Probe on October 15, 1997. Were you involved with the launch? Do you remember what that day was like?
My experience at the launch site is described in my earlier book Lifting Titan’s Veil. Like almost all of the scientists involved in Cassini’s development, I was just an interested spectator at the launch. It was a spectacular event – the launch was very early in the morning, and the rocket lit up a cloud from inside as it ascended, like a Chinese lantern. Everyone was tired, too tense to sleep before (and the launch had been attempted – and aborted – two nights before) but the adrenaline kept us going. Seeing the rocket launch safely was a great relief – there is always a few percent chance of a launch failing.
2.) What were the initial hopes for the Cassini mission –What was it sent to Saturn to do? Did it accomplish its mission? What is the Huygens probe?
Anticipating what scientific discoveries will be made is always a challenge, but Cassini and the Huygens probe (which parachuted down to Titan’s surface in 2005) were designed to answer some specific questions – like what is the composition of Titan’s atmosphere, and what is the nature of the surface. And Cassini/Huygens has basically answered these. But of course, Cassini’s findings have prompted a whole series of new and deeper questions.
3.) How have the Cassini mission and the Huygens Probe helped us understand Saturn and its moons better? What have been some of the more surprising findings?
Titan has been much more diverse than we expected – all our pre-Cassini ideas were very one-dimensional. Finding an Earth-like landscape with lakes and seas at the poles that contrasts with the huge fields of sand dunes at the equator was a total surprise. We also knew Enceladus might be interesting – there was some circumstantial evidence that it might be somehow geologically active, but nobody expected to see giant plumes of ice crystals hosing out into space.
4.) You have written two books about the moon Titan. What are some of the exciting findings about this moon?
The diversity of Titan’s landscape, which is both exotic and familiar, is one of the most interesting things for me. The close-up view from the Huygens probe, showing an area where methane rainfall had formed river channels and tumbled rocks around on the surface has profoundly set our picture of this world.
Another major finding has been the surprising richness of the organic chemistry in the upper atmosphere as Cassini flies through it. Instead of just a handful of molecules (as you’d find at Earth or Mars) there are dozens or hundreds of carbon-bearing compounds being formed up there. What’s really impressive to see now is the breadth of science being engaged at Titan – people who study sand dunes on Earth are interested, rivers, clouds; planetary rotation, organic chemistry, atmospheric electricity. Titan is like a huge scientific playground.
5.) The Cassini mission has been extended twice since its original mission. What do you think is next for Cassini?
The second mission extension has just begun, and is very bold – to continue operations until the Saturn/Titan northern summer solstice in 2017. So not only are there seven more years of observations to look forward to, but we expect to see some dramatic seasonal change in weather patterns on both Saturn and Titan. Cassini will not be the end of the Titan story. There are already very serious proposals for follow-on missions – to splash down and float in the polar seas, or to fly above the surface in a balloon or airplane.
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