Cassini is a NASA spacecraft that has orbited Saturn
On April 22, the probe took its last close-up photos of
Titan, Saturn’s largest moon.
Flying past the moon nudged Cassini onto a path that
will eventually destroy the spacecraft.
NASA’s long-lived Saturn probe, Cassini, has paid its final visit
to the planet’s largest moon, Titan.
The moon is larger than Earth’s and bigger than the planet
Mercury. It’s covered in thick haze and smog, contains seas of
liquid hydrocarbons, has a crust made of ice — and just might be
habitable to alien life.
Cassini flew by the giant moon and photographed it on April 22,
less than two weeks after the probe captured
an awe-inspiring image of Earth through the rings of Saturn.
The latest batch of images started arriving at Earth-based radio
dishes on April 23, after traveling 878 million miles through
deep space. Scientists are now taking the raw black-and-white
data and processing it into color photographs.
This shot, for example, merges red and near-infrared light (which
can pierce Titan’s thick atmosphere) from Cassini’s camera
sensor, revealing the partly-lit surface of Titan:
The blue-colored regions are dark material that researchers
believe are dry seabeds.
A closer view of Titan, likely taken within about 600 miles of
the moon, more clearly shows some of those dark areas:
With these and dozens of other new images, NASA locked in its final look at the
Scientists are especially curious about a “magic
island” that seems to consistently appear, disappear, and
reappear in one of Titan’s shallow seas over time.
“We don’t know what it is. It might be some hydrocarbon gas, and
these bubbles periodically come to the surface,” Linda Spilker,
a Cassini project scientist and a planetary scientist at NASA
JPL, told Business Insider, adding the gas might be methane or
ethane. “This happens in lakes on Earth.”
NASA would prefer to continue exploring Titan and other bodies
near Saturn with Cassini, but has said its plucky probe is
running out of fuel — and out of time.
Cassini’s coming doom
NASA launched Cassini in October 1997, and the
nuclear-powered probe reached the Saturn system following
seven years of flight. After it dropped off a probe called
Huygens in 2004, it began circling the planet and spying on
its vast collections of moons and rings.
However, the mission will soon
come to a fiery end.
The spacecraft is dangerously low on a propellant that’s required
to correct or change its orbit. Because Cassini has earthly
microbes stuck to its body, scientists don’t want the probe to
crash into and contaminate Titan or other moons like Enceladus,
an ice-encrusted world that’s hiding a warm saltwater
So, NASA is going to burn up the $3.26 billion probe in the thick
clouds of Saturn.
“Cassini’s own discoveries were its demise,” Earl Maize, an
engineer at NASA’s Jet Propulsion Laboratory (JPL) who manages
the Cassini mission, said during an April 4 press briefing.
“Cassini has got to be put safely away. And since we wanted to
stay at Saturn, the only choice was to destroy it in some
Cassini’s April 22 flyby of Titan marks the official start to
what NASA calls the spacecraft’s “Grand Finale“: a new, risky set of orbits
that will dive the probe through the relatively narrow gap
between Saturn and its rings.
The first ring-gap dive is slated to occur on April 26, and
Cassini will complete 20 similar dives in the coming months. But
in early September, Cassini will swing close enough to Titan for
the moon’s gravity to send the robot to its death.
“That final orbit gives us Titan’s goodbye kiss,” Spilker told
Business Insider. (If we get any images of Titan from that last
trip, they won’t be as close-up as this recent batch.)
The probe will enter Saturn’s atmosphere on September 15, 2017,
taking as many readings as it can before it breaks apart and
burns up. “I don’t think of this as killing Cassini. I see it as
a glorious end to an incredible mission,” Spilker said. “It’s
Cassini’s blaze of glory.”
Once Cassini vanishes, it may be the last probe that NASA sends
to Saturn for decades. There are currently no other missions to
Saturn or its moons on the books, and although the US government
is slowly making
plutonium-238 — a nuclear fuel that’s required to power
NASA’s most ambitious robots — the space agency’s current
stockpile has run too low to launch another Cassini.
New close-up photos of Saturn’s largest moon may be the last for decades – Business Insider