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This eclipse sequence
This eclipse sequence
begins at upper left
begins at upper left
and ends at lower right.
and ends at lower right.
During this event,
During this event,
the Moon moves from
the Moon moves from
west to east, across the
west to east, across the
Sun’s face.
2004-2017 2004-2017 DUAL TECHNIQUE DUAL TECHNIQUE MAGNETOMETER MAGNETOMETER �MAG� �MAG� Essentially a sensitive Essentially a sensitive and precise compass, and precise compass, MAG recorded the MAG recorded the strength and direction strength and direction of the magnetic �elds of the magnetic �elds around the spacecraft. around the spacecraft. It helped scientists It helped scientists learn about Saturn’s learn about Saturn’s magnetosphere as well magnetosphere as well as the interiors of the as the interiors of the planet and its moons. planet and its moons.
RADIO AND PLASMA RADIO AND PLASMA WAVE SCIENCE WAVE SCIENCE INSTRUMENT �RPWS� INSTRUMENT �RPWS�
As the name suggests, As the name suggests, this suite of antennas this suite of antennas and sensors detected and sensors detected radio and plasma waves. radio and plasma waves. The instrument “heard” The instrument “heard” radio emissions from radio emissions from lightning in Saturn’s lightning in Saturn’s atmosphere and from atmosphere and from the planet’s aurorae. the planet’s aurorae.
COMPOSITE INFRARED SPECTROMETER �CIRS� COMPOSITE INFRARED SPECTROMETER �CIRS�
This spectrometer captured infrared radiation and split it into its This spectrometer captured infrared radiation and split it into its component colors. Scientists used this information to deduce the component colors. Scientists used this information to deduce the temperature and composition of objects in the Saturn system. temperature and composition of objects in the Saturn system.
IMAGING SCIENCE IMAGING SCIENCE SUBSYSTEM �ISS� SUBSYSTEM �ISS� This instrument This instrument
contained a pair of digital contained a pair of digital cameras — a wide- cameras — a wide- angle one for context angle one for context and a narrow-angle and a narrow-angle one for high resolution. one for high resolution. ISS photographed the ISS photographed the Saturn system at visible, Saturn system at visible, ultraviolet, and infrared ultraviolet, and infrared wavelengths. wavelengths. ULTRAVIOLET IMAGING ULTRAVIOLET IMAGING SPECTROGRAPH �UVIS� SPECTROGRAPH �UVIS�
The four telescopes of UVIS The four telescopes of UVIS took ultraviolet images of took ultraviolet images of Saturn’s atmosphere, moons, Saturn’s atmosphere, moons, and rings, and also split the and rings, and also split the incoming light into its constitu- incoming light into its constitu- ent wavelengths to reveal the ent wavelengths to reveal the objects’ compositions. objects’ compositions.
VISIBLE AND INFRARED MAPPING SPECTROMETER �VIMS� VISIBLE AND INFRARED MAPPING SPECTROMETER �VIMS�
VIMS comprised two cameras: One operated at visible wavelengths, VIMS comprised two cameras: One operated at visible wavelengths, the other at slightly longer infrared wavelengths. The cameras the other at slightly longer infrared wavelengths. The cameras separated that light into its component colors, allowing scientists to separated that light into its component colors, allowing scientists to ascertain the temperature and composition of Saturn’s atmosphere ascertain the temperature and composition of Saturn’s atmosphere and rings as well as of the moons’ surfaces and atmospheres. and rings as well as of the moons’ surfaces and atmospheres.
OO
n October 15, 1997, the main engines of a Titan/Centaur rocketn October 15, 1997, the main engines of a Titan/Centaur rocket ignited, and the Cassini spacecraft and attached Huygens probe ignited, and the Cassini spacecraft and attached Huygens probe rose into the sky above Cape Canaveral, Florida. The rockets rose into the sky above Cape Canaveral, Florida. The rockets didn’t have enough power to get the pair out to Saturn, how- didn’t have enough power to get the pair out to Saturn, how- ever. So, Cassini and Huygens embarked on a circuitous trip through ever. So, Cassini and Huygens embarked on a circuitous trip through the inner solar system, stealing a bit of orbital energy from Venus the inner solar system, stealing a bit of orbital energy from Venus (in April 1998 and June 1999) and Earth (in August 1999). The probes (in April 1998 and June 1999) and Earth (in August 1999). The probes received an even bigger boost from massive Jupiter in December received an even bigger boost from massive Jupiter in December 2000, setting them on course to reach Saturn in June 2004. 2000, setting them on course to reach Saturn in June 2004.For 13-plus years, Cassini orbited the giant planet. Engineers For 13-plus years, Cassini orbited the giant planet. Engineers used the gravity of Saturn’s biggest moon, Titan, to t
used the gravity of Saturn’s biggest moon, Titan, to t weak itsweak its
course and get close-up views of the planet’s atmosphere, rings, course and get close-up views of the planet’s atmosphere, rings, magnetic field, and dozens of smaller but no-less-intriguing magnetic field, and dozens of smaller but no-less-intriguing moons. Early on, Huygens dropped
moons. Early on, Huygens dropped from Cassini, parachutingfrom Cassini, parachuting through Titan’s thick, hazy atmosphere and landing on
through Titan’s thick, hazy atmosphere and landing on the surfacethe surface in January 2005.
in January 2005. Together
Together, the , the two spacecraft carried two spacecraft carried 18 scientific instruments:18 scientific instruments: Cassini held 12 and Huygens six. These
Cassini held 12 and Huygens six. These powerful tools unveiled thepowerful tools unveiled the ringed world and its surroundings in
ringed world and its surroundings in unprecedented detail. Andunprecedented detail. And amazingly, only one of the
amazingly, only one of the orbiter’s instruments, the Cassini Plasmaorbiter’s instruments, the Cassini Plasma Spectrometer, failed before the spacecraft burned up
Spectrometer, failed before the spacecraft burned up in Saturn’sin Saturn’s atmosphere September 15, 2017, nearly 20 years after launch. atmosphere September 15, 2017, nearly 20 years after launch.
RADAR RADAR
This instrument sent radio signals through This instrument sent radio signals through Titan’s hazy atmosphere and recorded how Titan’s hazy atmosphere and recorded how long they took to return, allowing scientists long they took to return, allowing scientists to build high-resolution pictures of the to build high-resolution pictures of the moon’s surface.
moon’s surface.
RADIO SCIENCE SUBSYSTEM �RSS� RADIO SCIENCE SUBSYSTEM �RSS�
The RSS used Cassini’s high-gain antenna to The RSS used Cassini’s high-gain antenna to send radio signals to Earth through the rings send radio signals to Earth through the rings or the atmospheres of Saturn and its moons. or the atmospheres of Saturn and its moons. Scientists then studied how the intervening Scientists then studied how the intervening material altered the signal to learn more material altered the signal to learn more about its structure.
about its structure.
ION AND NEUTRAL MASS ION AND NEUTRAL MASS SPECTROMETER �INMS� SPECTROMETER �INMS�
This instrument determined the chemical This instrument determined the chemical composition of neutral particles and low- composition of neutral particles and low- energy ions, particularly in Titan’s upper energy ions, particularly in Titan’s upper atmosphere and in Saturn’s rings and atmosphere and in Saturn’s rings and magnetosphere.
magnetosphere.
CASSINI PLASMA SPECTROMETER CASSINI PLASMA SPECTROMETER �CAPS�
�CAPS�
CAPS measured the energy, electrical charge, CAPS measured the energy, electrical charge, and direction of motion of
and direction of motion of charged particlescharged particles.. One of its
One of its sensors also determined the masssensors also determined the mass of each particle. A short
of each particle. A short circuit in CAPS endedcircuit in CAPS ended its life in June 2012.
its life in June 2012.
MAGNETOSPHERIC IMAGING MAGNETOSPHERIC IMAGING INSTRUMENT �MIMI�
INSTRUMENT �MIMI�
MIMI’s three sensors worked in concert MIMI’s three sensors worked in concert to detect energetic charged particles in to detect energetic charged particles in Saturn’s vast magnetosphere, to under- Saturn’s vast magnetosphere, to under- stand how it interacts with the
stand how it interacts with the solar wind.solar wind.
ON THE BACK SIDE
ON THE BACK SIDE
COSMIC DUST ANALYZER �CDA� COSMIC DUST ANALYZER �CDA�
This detector established the size, speed, This detector established the size, speed, direction of motion, and chemical compo- direction of motion, and chemical compo- sition of tiny dust particles near Saturn. sition of tiny dust particles near Saturn.
DOPPLER WIND DOPPLER WIND EXPERIMENT �DWE� EXPERIMENT �DWE�
DWE recorded wind DWE recorded wind speeds of up to 270 mph speeds of up to 270 mph (430 km/h) in Titan’s (430 km/h) in Titan’s atmosphere. Although atmosphere. Although Cassini never received Cassini never received the data, Earth-based the data, Earth-based radio telescopes recov- radio telescopes recov- ered some of it. ered some of it.
GAS CHROMATOGRAPH GAS CHROMATOGRAPH MASS SPECTROMETER MASS SPECTROMETER �GC/MS� �GC/MS�
This instrument pair This instrument pair analyzed gases in Titan’s analyzed gases in Titan’s atmosphere at high atmosphere at high altitudes and near the altitudes and near the surface. The two deter- surface. The two deter- mined how the abun- mined how the abun- dances of nitrogen and dances of nitrogen and methane changed with methane changed with altitude and discovered altitude and discovered argon in the air. argon in the air.
HUYGENS HUYGENS ATMOSPHERIC ATMOSPHERIC STRUCTURE STRUCTURE INSTRUMENT �HASI� INSTRUMENT �HASI�
Multiple sensors measured Multiple sensors measured the density, pressure, the density, pressure, temperature, and electrical temperature, and electrical properties of Titan’s atmo- properties of Titan’s atmo- sphere during the probe’s sphere during the probe’s descent. A microphone descent. A microphone also recorded sounds. also recorded sounds.
DESCENT IMAGER/SPECTRAL DESCENT IMAGER/SPECTRAL RADIOMETER �DISR�
RADIOMETER �DISR�
This instrument’s imagers built This instrument’s imagers built up mosaics of the moon’s surface up mosaics of the moon’s surface in the landing site’s vicinity. Solar in the landing site’s vicinity. Solar sensors measured the Sun’s sensors measured the Sun’s intensity and allowed scientists intensity and allowed scientists to study the size and density of to study the size and density of airborne particles. Still another airborne particles. Still another sensor measured the atmo- sensor measured the atmo- sphere’s heat �ow.
sphere’s heat �ow.
AEROSOL COLLECTOR AND PYROLYSER �ACP� AEROSOL COLLECTOR AND PYROLYSER �ACP�
The ACP pulled in aerosol particles and heated them to vapor- The ACP pulled in aerosol particles and heated them to vapor- ize volatile substances and decompose organic compounds. ize volatile substances and decompose organic compounds. It then passed these products to the GC/MS for analysis. It then passed these products to the GC/MS for analysis.
SURFACE SURFACE SCIENCE SCIENCE PACKAGE �SSP� PACKAGE �SSP� Multiple sensors Multiple sensors helped determine helped determine the physical proper- the physical proper- ties of the surface ties of the surface at Huygens’ landing at Huygens’ landing site, including site, including its hardness and its hardness and structure. Several of structure. Several of SSP’s sensors were SSP’s sensors were designed to work in designed to work in a liquid environ- a liquid environ- ment in case the ment in case the probe landed in a probe landed in a sea or ocean. sea or ocean.