Tag: Cassini
The dunes of Titan
Engineers have gone to a back up radio system on Cassini after a primary unit did not respond as expected in late December.
Engineers have gone to a back up radio system on Cassini after a primary unit did not respond as expected in late December.
The cause is still under investigation, but age may be a factor. The spacecraft launched in 1997 and has orbited Saturn since 2004. Cassini completed its prime mission in 2008 and has had two additional mission extensions. This is the first time its ultra-stable oscillator has had an issue.
Engineers have gone to a back up radio system on Cassini after a primary unit did not respond as expected in late December.
The cause is still under investigation, but age may be a factor. The spacecraft launched in 1997 and has orbited Saturn since 2004. Cassini completed its prime mission in 2008 and has had two additional mission extensions. This is the first time its ultra-stable oscillator has had an issue.
Cassini’s top ten images for 2011
The year long mega storms of Saturn
The giant storm on Saturn
A global map of Titan, in color
Sponge in space
On August 25 Cassini did a close fly-by of the small Saturn moon Hyperion, getting as close as 15,500 miles. The mission has just released images from that fly-by.
Looks like a sponge, doesn’t it? This moon is small, only 168 miles across, which makes it about half the size of the asteroid Vesta that Dawn is presently orbiting. Why it is so peppered with craters is of course the big science question. I would guess this has something to do with the environment around Saturn, with its rings and the innumerable particles that come from it. Yet, other moons of Saturn are not as crater-filled, so there is obviously more to this than meets the eye.
This fly-by was the second closest of Hyperion that Cassini has done, the first passing over the the moon’s surface by only 310 miles. Because the irregularly-shaped moon’s rotation is more like a chaotic tumble, scientists could not predict what part of the surface they would see. To their luck the new images captured new territory.
Another fly-by is scheduled in only three weeks, on September 16, 2011. This time, however, the spacecraft won’t get as close, passing at a distance of about 36,000 miles.
What caused a giant arrow-shaped cloud on Saturn’s moon Titan?
What caused a giant arrow-shaped cloud on Saturn’s moon Titan?
What caused a giant arrow-shaped cloud on Saturn’s moon Titan?
Cassini captures a truly huge storm on Saturn.
Cassini has captured an image of a truly huge storm on Saturn. Click on the image below to see the full image.
Cassini has captured an image of a truly huge storm on Saturn. Click on the image below to see the full image.
Cassini directly samples the plumes from Enceladus and finds an ocean-like Spray
Cassini has directly sampled the plumes from Enceladus and discovered a salty ocean-like spray.
The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. The icy particles hit the detector target at speeds between 15,000 and 39,000 mph (23,000 and 63,000 kilometers per hour), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.
The data suggest a layer of water between the moon’s rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.
Cassini has directly sampled the plumes from Enceladus and discovered a salty ocean-like spray.
The new paper analyzes three Enceladus flybys in 2008 and 2009 with the same instrument, focusing on the composition of freshly ejected plume grains. The icy particles hit the detector target at speeds between 15,000 and 39,000 mph (23,000 and 63,000 kilometers per hour), vaporizing instantly. Electrical fields inside the cosmic dust analyzer separated the various constituents of the impact cloud.
The data suggest a layer of water between the moon’s rocky core and its icy mantle, possibly as deep as about 50 miles (80 kilometers) beneath the surface. As this water washes against the rocks, it dissolves salt compounds and rises through fractures in the overlying ice to form reserves nearer the surface. If the outermost layer cracks open, the decrease in pressure from these reserves to space causes a plume to shoot out. Roughly 400 pounds (200 kilograms) of water vapor is lost every second in the plumes, with smaller amounts being lost as ice grains. The team calculates the water reserves must have large evaporating surfaces, or they would freeze easily and stop the plumes.
A storm ten times bigger than Earth
Saturn and Enceladus linked by electricity
Saturn and Enceladus linked by electricity.
Saturn and Enceladus linked by electricity.
The spring rains (of methane) have arrived on Titan
The spring rains (of methane) have arrived on Titan.
The spring rains (of methane) have arrived on Titan.
Cassini goes into safe mode
Cassini went into safe mode on Tuesday, November 2nd. At the moment engineers expect it to take at least another week to get the spacecraft back to normal.
Cassini went into safe mode on Tuesday, November 2nd. At the moment engineers expect it to take at least another week to get the spacecraft back to normal.
Liquid on Titan
The Cassini image below, released today at the 42nd meeting of the AAS Division for Planetary Sciences, shows light reflecting off a lake on Titan’s northern hemisphere. According to the scientists who took the image, this is the first definitive confirmation of the presence of liquid in those lakes.
Saturn from above
This breath-taking image of Saturn and its rings was taken by Cassini on July 19, 2009 and posted on the Cassini image gallery on August 27, 2010.
Scientists measure the rise and fall of lakes on Titan
It appears we are entering the dry season on Titan. Scientists have observed a 1 meter drop in the levels of Titan’s methane lakes over the last four years as the seasons on the moon go from summer to fall. Fun quote: “[The scientists] report that the shoreline of Ontario Lacus receded by about 10 kilometers (6 miles) from June 2005 to July 2009.”
It appears we are entering the dry season on Titan. Scientists have observed a 1 meter drop in the levels of Titan’s methane lakes over the last four years as the seasons on the moon go from summer to fall. Fun quote: “[The scientists] report that the shoreline of Ontario Lacus receded by about 10 kilometers (6 miles) from June 2005 to July 2009.”