The Computer Vet Weblog

The Cassini space probe is almost finished with its seven-year-long journey to Saturn. It’s already inside the orbits of a few of the outer moons, and it even did a close pass by one of them. On July 1st it will come this close to the planet itself, and go through a braking maneuver that will slow it down enough to get caught in Saturn’s gravity. After that, it will spend at least four years in a lazy orbit, visiting many of the moons and expanding what we know about Saturn by a factor of a thousand.

Personally, I have a special place for Cassini. It’s the only satellite I’ve actually seen—up close, at least. It was during the whirlwind days of the summer of 1997. Pathfinder had just landed on Mars, and Galileo was sending back some of its best pictures from Jupiter. There was definitely a giddy atmosphere around the Jet Propulsion Laboratory, and a friend of a friend was doing a summer intership there in Pasadena. So we dropped by and got the grand tour. Mostly all we saw was building after building of offices, chock full of scientists and officials. But then we came around the corner to one large warehouse, with separate public and private entrances. This was Building 179, the Spacecraft Assembly Facility. Through the public entrance was a sealed viewing area where we could look out over the assembly bay. And in the bay that summer was Cassini, undergoing final preparations for launch. I had been following Galileo’s mission to Jupiter that year, and knowing this machine I was looking at would soon be doing the same thing around Saturn was thrilling. Too bad I would have to wait seven years.

Three months later Cassini launched amid much protest over the radioactive fuel it carried. Protesters were worried that the spacecraft would break apart either on launch, or during its gravity-assist flyby two years later, and shower Earth’s atmosphere with plutonium. NASA insisted the likelihood of that was very small, and indeed Cassini survived the launch and the flyby, as well as two flybys of Venus and one of Jupiter. It was well on its way to its target.

JPL is handling the mission and the spacecraft, but the Ciclops Imaging team are the ones in charge of Cassini’s cameras. They’ve been assembling some remarkable photos during Cassini’s voyage so far, including closeups of Earth’s moon as well as one of the best portraits of Jupiter ever taken. These pictures were taken as much to test Cassini’s systems as they were for their scientific and aesthetic value. It all was done to pass the time, and to prepare for the real target, Saturn.

The ringed planet was first spotted in late 2002, and ever since the cameras have just been snapping ever-bigger photos of the approach. November, February, March. There was some excitement last week when Cassini flew by the outer moon Phoebe. The mission is about to begin. In two weeks the spacecraft will swing through the rings, hit the brakes, and get to work. In January it will launch a probe that will drop into the atmosphere of, and hopefully land on the surface of, the moon Titan. And for the next four years, after seven of waiting, we’ll be seeing pictures of Saturn and its moons that we could never dream of.

It’s about time!