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Carolyn Porco
Cassini Imaging Team Leader
As you can imagine, we Cassini imaging scientists have been bee-busy trying to understand what our recent images from this week's Enceladus flyby are telling us about the nature of the moon's south polar surface and sub-surface environments.
I can now report that, so far, we have successfully located the surface sources of the jets for which Enceladus has become renowned.
There is still much more to do to see if we can glean any information at all about the eruptive process itself from the geological characteristics we see on the surface. But this, you have to admit, is a very good start!
Click here for our latest release.
Image left: Surface sources of some jets on Enceladus. Full image and caption
And click here for a similar image.
John Spencer
Cassini Scientist on the Composite Infrared Spectrometer (bio)
Click here to browse Cassini raw images site for Enceladus images
circumstances, and by the bizarre landscape that they revealed. Utterly stunning. Hats off to the imaging team, particularly (as Bonnie and Carolyn also mentioned) to Paul Helfenstein, who sweated for months on the details of planning that sequence.
Bonnie J. Buratti (bio)
Cassini Scientist on the Visual and Infrared Mapping Spectrometer
What a way to start Cassini’s extended mission! On Tuesday afternoon (Aug. 12, 2008) about 50 scientists sat in the Spaceflight Operations Facility at JPL to view the images as they came down.
I was as dumbfounded as anyone, but rapt in awe to be among a privileged group of humans to see another part of nature for the first time. How fantastic that the public can share in this excitement through the raw image gallery . Those few sublime moments were worth the many months of drudgery that went into planning these observations. Some of the views were of old familiar terrains, roads that we traveled many times. But many of the features revealed were new, and seeing them evoked the same level of astonishment I experienced at my first sight of the Grand Canyon or
Image left: That's me to the lower left of the image screen. My colleagues and I gathered to look at these raw images from Enceladus.
Inspiring as that first peek at new data was, I am now confronted with Thomas Edison’s cogent remark about the nature of discovery: it’s one percent inspiration and 90 percent perspiration. Much of the most important discoveries to come from this flyby will be squeezed out of the data over the coming days and weeks: teams of scientists poring over the measurements, analyzing, massaging, modeling, thinking, going up blind alleys – that is just the nature of research. It is also very much a team approach, with each member contributing from an area in which they are expert.
Jerry Jones, who heads the Cassini Navigation Team, told the assembled scientists yesterday that we came within one kilometer of our planned trajectory. Instead of a close approach of 50 km (30 miles), we came within 49 km of the surface of Enceladus. That Navigation Team is awesome! Imaging scientist Paul Helfenstein built a clever sequence at closest approach that was designed to place observations right on the hot tiger stripes, and which he nicknamed the "skeet shoot" (explained in Amanda's first post). The skeet shoot that was successfully executed on August 11 was equivalent to the clay pigeon being thrown into the air in
How fortunate we are to have the spacecraft alive and well, with all systems and scientific instruments operating. What we saw at Enceladus represents just a small part of what we will learn over the coming years. There are six more targeted flybys of Enceladus coming up over the two years of the extended mission. There is still so much to learn about the ringed planet and its family of moons.
Amanda Hendrix (bio)
Cassini scientist on the Ultraviolet Imaging Spectrograph
Well as luck would have it, much of my day yesterday was spent on an airplane flying to
Image left: Here's an example of a raw image from Enceladus. Click here for the full image
Went back to my seat, experiencing the first waves of absolute thrill that I always get during these flybys, and happiness because I am so lucky to do this for a living! What fun. I switched to something more upbeat than Sigur Ros ... I'm thinking old school Oingo Boingo or maybe some MGMT. I'm excited to see these data!
And now it’s Wednesday morning and we’ve all seen the fabulous images. All the excitement was well-founded. Golly, indeed! I’m having fun digging through the UVIS data and we’ll see what they reveal about the south polar region. What an interesting, fascinating little world. What a surprising bit of insight into solar system processes! Thanks to Paul Helfenstein and the Imaging Team for their hard work on the closest-approach “skeet shoot” and mosaic, and to the entire Cassini spacecraft team for their diligence in making this flyby work so incredibly well!
Cheers from
Amanda
Carolyn Porco
Cassini Imaging Team Leader
Click this link to go to raw images from Cassini.
Well, folks, the images are down ... at last!! ... and I can't print here what I first said upon seeing them. What a dazzling success! There doesn't even appear to be any smear. Paul Helfenstein (imaging team associate who planned the images), you genius ... here's one big hug from me, man! We here at CICLOPS are all giddy, even moved to tears.
Clearly the skeet shoot maneuver worked (skeet shoot maneuver explained here: http://blogs.nasa.gov/cm/blog/cassini-aug08.blog/posts/post_1218130703424.html). From our first examination, it appears we so far have the first, third, fourth, and seventh skeet shoot footprints down, and they are upside down from the footprints displayed in our graphic at http://ciclops.org/view/5156/Enceladus_Rev_80_Flyby , so beware of that.
The first two images have captured terrain near (1st skeet shoot) and on (3rd skeet shoot) Cairo Sulcus, and are clearly littered, completely, with blocks of ice ... not surprising given that we saw such things in our first very high res 4-meter/pixel resolution images taken back in 2005, and not surprising for a very fractured environment. The next image, our 4th skeet-shoot image (the image on the left here), is also littered with blocks and apparently has caught two unnamed fractures between
It seems our pointing has been fabulous, especially for the later images. Helfenstein
... here's another big hug from me. You're one cool dude!!
Now we have to figure out if we indeed have captured the sites where the jets are
emerging, so there’s a lot more to do.
But I ask you: Is there ANYTHING more exciting, more thrilling, more stimulating to the mind, more gratifying to the soul than exploring news worlds?!!!
Carolyn Porco
Cassini Imaging Team Leader
I woke up unusually early this morning, on pins and needles, and looked
out my bedroom window from my house on a narrow ridge in northern
town below, and wondered how the day would unfold. I paused to let my
gaze fly, in my mind, beyond the horizon and around and over the Earth,
pulling back in `powers of ten' fashion, imagining our planet suspended
in space. And I thought about how remarkable the inhabitants of that
small blue world truly are, and how extraordinary their achievements
over these past 4 years have been.
Those years of intensive examination of an alien planetary system have
brought us humans to this juncture, right now, awaiting news from clear
across the solar system of the outcome of our latest bold experiment in
interplanetary maneuvering, focused on one of the most fascinating
places in our solar system... a place we never even knew existed before
we set out on this adventure.
In this painstaking work, we proceed, step by step, to lay bare those
things which hold the greatest promise of comprehension, the greatest
significance for piecing together the story of the origins of the
bodies in our solar system, our Earth, and indeed ourselves.
The images we await now are just a few of those steps. I wonder: What
will they show?
Todd Barber
Cassini Lead Propulsion Engineer (bio)
Hello from the "flip" side of Enceladus! I'm happy to report via this blog that the Deep Space Network in
We've executed yet another successful flyby of Saturn's ice-geyser moon! Playback data has just begun streaming to our breathless scientists and engineers at JPL, and it will continue throughout the evening and into tomorrow morning. With the rest of you, I'm pumped up for the raw (unprocessed) images that will be posted Tuesday morning, Pacific Time. For the latest raw images, check here:
http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list1.html
Cassini engineering may pay my bills, but Cassini science sparks my passions.
A few engineers are still here, working away this evening, making sure the spacecraft came through its scientific marathon unscathed. I can't speak for all these engineers, but I can tell you the propulsion subsystem is healthy and is ready for yet another Reaction Wheel Assembly (RWA) bias after midnight PDT. Thankfully, this activity is fairly commonplace, so long before then I plan to be celebrating another engineering success with some Olympics viewing, perhaps an appropriate beverage, and an indefatigable smile. It's been a long day but oh so tremendous! Now let the flood of Enceladus science data commence!
Todd
Carolina Martinez
JPL News Team
This is a video clip of the Cassini mission control area and Grant Eller, on console, confirming with the Deep Space Station in
Here is a high-resolution, broadcast quality clip of the same event: High-resolution clip
And here's an interview clip with Todd Barber, Cassini lead propulsion engineer: Play clip
You can get a high-resolution, broadcast quality clip of Todd here: High-resolution clip
Tomorrow we will have more postings from our scientists and engineers and their comments on the images.
Raw images may begin to appear in the pre-dawn hours (PDT) with some of the best raw views arriving in the late afternoon. For the latest raw images see: http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-list1.html
Best wishes from Pasadena, California on this fine day! As I write
the highly anticipated Enceladus flyby is underway.
I was in the office this weekend trying to get caught up a bit (a
weekend tradition), allowing me to hit the ground running on another
busy work week. This week holds exciting promise and scientific
anticipation, though, in addition to my typical engineering duties.
Over the weekend, we did two Reaction Wheel Assembly (RWA) biases to
optimize the rotational speeds of these objects. Through angular
momentum changes, these wheels can turn and point the spacecraft,
allowing incredible precision. One of my tasks is to calculate how
much propellant these biases use, so that's one thing I'm working on
today.
Speaking of propellant usage, there have been some questions about how
much propellant we will use in the maneuvers around Enceladus and for
the flyby itself. As I mentioned in my prior blog entry, we were
actually able to cancel our approach maneuver, OTM-163. In addition,
the next propulsive maneuver (OTM-164) is nearly two weeks off,
setting up Cassini for solar conjunction and yet another Enceladus
encounter (E5) in October. OTM-164 will be rather large, however,
using roughly 10 kg of bipropellant, about 6 kg of nitrogen tetroxide
(oxidizer) and 4 kg of monomethylhydrazine (fuel). For the E4
encounter itself, I don't have a propellant-usage prediction handy,
but I can tell you it will be at most a few tens of grams of hydrazine
(the monopropellant fuel), for yet another RWA bias.
The bottom line is that we have plenty of propellant for our two-year
extended mission and beyond. Thanks for that great question, and
we'll see all of you on the other side of Enceladus!
Todd
John Spencer
Cassini Scientist on the Composite Infrared Spectrometer (bio)
Our next Enceladus encounter is very soon, at 21:06 Universal Time or 14:06pm Pacific time. This promises to be a spectacular encounter, giving our first high-resolution sunlit view of the south polar region since the discovery of activity there three years ago (the most recent encounter, in March 2008, observed the south pole only in the darkness of Saturn's shadow). Our instrument, the Composite Infrared Spectrometer (CIRS), will be mapping the heat radiation from the warm tiger stripes as we did in last March's flyby, but on that flyby our best views were from a range of 14,000 km (8,500 miles), allowing us to see details of the heat radiation on scales as small as 4 km (2.5 miles). This time we'll start our observations from a range as close as 900 km (560 miles), showing us Enceladus in fabulous close-up, with CIRS mapping details as small as 270 meters (0.17 miles). As we scan the south pole we're screaming away from Enceladus at nearly 18 kilometers/second (40,000 mph) so we have to work fast to make the most of this high-resolution opportunity.
Image left: Heat radiation from tiger stripes. Full caption
I'm most excited about the observation we'll be attempting at about 21:11 UT, when we will try to put the CIRS short-wavelength detector right along one of the most active tiger stripes, called Damascus Sulcus, from a distance of only 4,500 km (2,800 miles). On our last flyby we saw temperatures as high as at least 180 Kelvin (-135 Fahrenheit) on this part of Damascus, from 15,000 km (9,000 mile) range, and from three times closer we might see even higher temperatures because the warm material, which we think occupies a strip just tens or hundreds of meters wide along the fractures, will fill more of our detector and give us a more accurate reading. However, this is a challenging observation because our detector consists of a linear array of ten pixels, which will be aligned parallel to the fracture. Pointing may not be perfect this close to the moon, so we may get all ten detectors, or none of them, on Damascus. You might ask why we didn't align the detector across the fracture rather than parallel to it, to be sure that at least some of our pixels would fall on the warm material. But we needed to align the spacecraft in the direction that allows it to rotate as fast as possible to keep up with Enceladus as we zoom past, and we didn't have the luxury of also optimizing the orientation of the detector.
The animation to the right depicts Cassini flying close to Enceladus.
So tomorrow morning, when we hope the data will be processed and ready for us to look at, we'll be both nervous and excited to see if this particular gamble paid off. But even if we are unlucky in this case, we'll get lots of other spectacular data. Here's a blow-by-blow account of the planned CIRS observations of the south pole, with times given in Universal Time (UT):
1 - 10 of 14 posts. | Total pages: 2 Goto |