On its last orbits in 2017, the long-running Cassini spacecraft dove between Saturn’s rings and its upper atmosphere and bathed in a downpour of dust that astronomers call “ring rain.”
In research published today in Science, LASP research associate Hsiang-Wen (Sean) Hsu and his colleagues report that they successfully collected microscopic material streaming from the planet’s rings.
The findings, which were made with Cassini’s Cosmic Dust Analyzer and Radio and Plasma Wave Science instruments, come a little more than a year after the spacecraft burned up in Saturn’s atmosphere. They stem from the mission’s “grand finale,” in which Cassini completed a series of risky maneuvers to zip under the planet’s rings at speeds of 75,000 miles per hour.
LASP planetary scientist Larry Esposito has been eying the fabulous rings of Saturn for much of his career, beginning as a team scientist on NASA’s Pioneer 11 mission when he discovered the planet’s faint F ring in 1979.
He followed that up with observations of Jupiter’s and Saturn’s rings from the Voyager and Galileo spacecraft, which carried instruments designed and built at LASP. Now, as the principal investigator for the Ultraviolet Imaging Spectrograph (UVIS) on the Cassini-Huygens mission to Saturn, Esposito and his Cassini colleagues are feeling a bit somber as the mission nears its end. The spacecraft has run out of fuel and will disintegrate in Saturn’s dense atmosphere early on the morning of Sept. 15.
Toting an ultraviolet instrument designed and built by LASP, NASA’s Cassini spacecraft made the first of 22 dives between the rings of Saturn and the gaseous planet today, the beginning of the end for one of NASA’s most successful missions ever.
Launched in 1997 and pulling up at Saturn in 2004 for the first of hundreds of orbits through the Jovian system, the Cassini-Huygens mission has fostered scores of dazzling discoveries. These include in-depth studies that date and even weigh the astonishing rings; the discovery of methane lakes on the icy moon Titan; hot water plumes found squirting from the moon Enceladus; and closeup views of the bright auroras at the planet’s poles.
Planetary scientists are a step closer to understanding changes in the puzzling jets of gas and dust grains observed shooting into space from cracks on the icy surface of Enceladus, a moon of Saturn.
First observed in 2005 by NASA’s Cassini spacecraft as it orbited the ringed planet, the plume is coming from a subterranean, salty ocean beneath the moon’s surface. The latest observations with NASA’s Cassini spacecraft now at Saturn by a team including Larry Esposito, LASP planetary scientist and University of Colorado Boulder professor, indicate at least some of the narrow jets there blast with increased fury when the moon is farther from Saturn.
Scientists with NASA’s Cassini mission, led by LASP and University of Colorado postdoctoral researcher, Sean Hsu, have found that microscopic grains of rock detected near Saturn imply hydrothermal activity is taking place within the moon Enceladus.
This is the first clear indication of an icy moon having hydrothermal activity—in which seawater infiltrates and reacts with a rocky crust, emerging as a heated, mineral-laden solution. The finding adds to the tantalizing possibility that Enceladus, which displays remarkable geologic activity including geysers, could contain environments suitable for living organisms.
The results were published today in the journal Nature.
The Smithsonian National Air and Space Museum presented the 2012 Trophy for Current Achievement, its highest group award, to the NASA Cassini-Huygens Mission to Saturn on March 21 in Washington, D.C. The Cassini spacecraft carries the LASP-built Ultraviolet Imaging Spectrograph Subsystem (UVIS), which measures ultraviolet light in Saturn’s system to better understand the planet’s atmospheres,… Read more »
Using data from the NASA New Horizons mission to Pluto, LASP scientists have made new measurements of interplanetary dust density. The data, collected from the CU-Boulder student-built Student Dust Counter (SDC) and the meteoroid detector on the Pioneer 10 spacecraft, represent measurements of the micro-sized dust grains from the Earth out to the present position of the SDC, at approximately 20 Astronomical Units (AU). One AU is equal to the average distance from the Sun to the Earth, or approximately 93 million miles (149.5 million km).
In 1977, Jimmy Carter was sworn in as president, Elvis died, Virginia park ranger Roy Sullivan was hit by lightning a record seventh time and two NASA space probes destined to turn planetary science on its head launched from Cape Canaveral, Fla. The identical spacecraft, Voyager 1 and Voyager 2, were launched in the summer and programmed to pass by Jupiter and Saturn on different paths. Voyager 2 went on to visit Uranus and Neptune, completing the “Grand Tour of the Solar System,” perhaps the most exciting interplanetary mission ever flown. University of Colorado Boulder scientists, who designed and built identical instruments for Voyager 1 and Voyager 2, were as stunned as anyone when the spacecraft began sending back data to Earth.
Using data from the NASA Cassini mission, a team of scientists led by LASP researcher Sean Hsu, has successfully modeled dust streams being expelled from Saturn at speeds of more than 62 miles (100 km) per second. The data, taken from the Cosmic Dust Analyzer (CDA) and the magnetometer on board Cassini, provide new information about the sources of the dust, as well as interactions within the mix of subatomic particles in which the charged dust is immersed, called dusty plasma.
A study published in the journal Nature and co-authored by LASP scientist Sascha Kempf indicates that samples of water vapor and ice particles coming from Saturn’s icy moon Enceladus demonstrate evidence for a large, subterranean salt-water reservoir. The Cosmic Dust Analyzer (CDA) on board the NASA Cassini spacecraft measured the composition of plumes—emanating from fractures called tiger stripes—and found that ice grains close to the moon are salt rich, unlike those that make up the planet’s E Ring.
LASP scientist Glen Stewart recently co-authored a study published in The Astrophysical Journal concerning the formation of large moons around Jupiter and Saturn. The study shows that the differences between the satellites of Jupiter and Saturn—Jupiter has four large moons while Saturn has only one large moon and many small icy moons—informs how the moons were formed.
Press Release for 2007 DPS Meeting Saturn’s rings may be more massive than previously thought. Both Cassini observations and theoretical simulations of Saturn’s rings point towards extensive particle clumping in Saturn’s rings. Our simulations of the rings show that the surface density of particles can be substantially larger than one would infer from a uniform… Read more »