On Feb. 14, 1779, Capt. James Cook, the British explorer, was captured and, uh, cooked by Hawaiian natives. Perhaps not since then has there been such a fiery demise as this morning’s flaming end to the historic space explorer Cassini.
The death of Cassini (Giovanni Domenico Cassini was an Italian mathematician and astronomer, 1625-1711) was actually a radioed suicide command. Twenty years after a fiery launch and 13 years after arriving to peer around the magical planet of Saturn and its many moons, Cassini was running low on maneuvering fuel.
Rather than crashing into a pristine moon, possibly contaminating who-knows-what with who-knows-what, Jet Propulsion Laboratory engineers working with NASA back in April sent the fatal command to the intrepid robot to maneuver into its last 22 descending orbits on a new voyage of discovery — to explore for the first time the mysterious area inside the rings of Saturn.
Those final orbits and that journey ended early this morning as it began, in a fiery trip, this time plunging into Saturn’s enveloping atmosphere.
One of the gas-giant planets, Saturn has long fascinated earthbound viewers because of its stunningly precise rings of debris and ice encircling the immense place. In case you think Earth is a major player in this solar system, here’s how big Saturn is: Its diameter is 18 times larger than Earth’s.
It’s been an epic 13-year journey of exploration and unbelievable long-distance engineering. Cassini, which weighed 12,600 pounds on Earth, took thousands of photos over the years, including the one above. Look closely at the tiny white dot in the lower right by the arrow. That’s us, a kind of Earth selfie.
Traveling thousands of miles an hour, Cassini diligently sent each image home on radio signals that traveled at the speed of light — and still took eight minutes and 21 seconds to reach antenna nearly the size of football fields waiting at places like Madrid, Canberra and NASA’s Goldstone range in California.
In 2005, Cassini successfully dropped off the European Space Agency’s Huygens lander to explore Titan, a giant Saturn moon harboring a sea of liquid methane. Cassini found new rings on Saturn. It discovered that the icy crust of another moon, Enceladus, actually covers a vast underground ocean of water, a key ingredient for life as we know it.
Not only that, but for some reason huge plumes of moisture invisible from Earth spew from cracks in that ice some 50 miles out into space. Mysteriously, those high-pressure jets of water carry grains of sand. You can bet future spacecraft will be tasked to visit those fissures.
Engineers who’ve spent much of their professional life guiding, maintaining and talking with Cassini gathered in JPL’s campus-like Pasadena headquarters during the night for a kind of space wake. From 7 a.m. to 8:30 Eastern time NASA-TV’s cable channel carried a live video feed of Mission Control. And a post-mission news conference was scheduled for broadcast from there at 9:30 a.m. Eastern.
The obedient little machine sent home data to the very end, revealing possible secrets of Saturn’s atmosphere. With their last waning bursts, Cassini’s navigational thrusters struggled ever harder against the craft’s buffeting to keep the radio dish pointed toward home.
Then about 7:55, in an instant the metal and electronics disintegrated in a fiery flash across Saturn’s sky, like a plunging meteor that no one saw. And Cassini became a part of the place it had studied for so long.
Exactly 499 seconds later, Cassini’s last signal finally reached the waiting radio dish in California before the transmission disintegrated too, becoming both static and history.