Never before has a space probe come so close to the pint-sized moon embedded in Saturn’s rings — and when NASA’s Cassini buzzed Pan, the spacecraft revealed what a strange moon it really is.
This is Pan, a 22 mile-wide moon that scoots through Saturn’s rings, orbiting the gas giant once every 13.8 hours. And it’s weird.
Resembling a giant ravioli or some kind of “flying saucer” from a classic alien invasion sci-fi comic, Pan is known as a “shepherd moon” occupying the so-called Encke Gap inside Saturn’s A Ring. This gap is largely free of particles and it has become Pan’s job to hoover up any stray material — the moon’s slight gravity pulls particles onto its surface and scatters others back out into the ring system. This gravitational disturbance creates waves that ripple through the ring material, propagating for hundreds of miles.
On March 7, NASA’s Cassini mission came within 15,268 miles of Pan, revealing incredible detail in the moon’s strange surface. It’s thought that its characteristic equatorial ridge (a trait it shares with another Saturn moon Atlas) is caused by the gradual accumulation of ring material throughout the moon’s formation and with these new observations, scientists will be able to better understand how Pan came to be.
As Cassini rapidly approaches the end of its mission, eventually orbiting through Saturn’s ring plane as a part of its “Grand Finale,” we can expect more of these striking views from orbit before the veteran probe is steered into Saturn’s atmosphere in September, bringing its historic mission to an end.
Evidence is mounting around the cryovolcanic history of the solar system’s innermost dwarf planet — and its most recent eruptions may have happened within the last four million years.
Since NASA’s Dawn mission arrived at dwarf planet Ceres in 2015, we’ve been treated to some wonderfully detailed images of the small world’s pockmarked terrain. Understanding the underlying processes of what is believed to be an ice-filled celestial body, however, is taking some time to decipher. But with more observations comes more understanding and planetary scientists are getting close to realizing what lies beneath those craters and, possibly, unlocking the secrets behind a very icy and very alien phenomenon we have no experience of in our terrestrial lives.
That phenomenon is cryovolcanoes. And Ceres seems to have them.
The most startling feature on Ceres is Occator Crater. This 57 mile-wide feature is the result of a massive impact tens of millions of years ago. Large craters on small worlds isn’t necessarily a strange thing in our battered solar system, but what is strange about Occator is the very bright feature (and small bright patches surrounding it) in the crater’s center. Even before Dawn arrived in orbit and only fuzzy images of Ceres were available, hopes were high that this bright anomaly in the otherwise gray Cererian landscape could be indicative of ices or some mineral compound that was formed by the presence of water.
Cryovolcanoes — or, simply, ice volcanoes — are hypothetical features that are believed to be common throughout the outer solar system. These ice volcanoes are thought to erupt in a similar fashion to the volcanoes we have on Earth, but instead of molten rock, these volcanoes erupt ice-cold volatiles — like water, methane or ammonia. Dwarf planet Pluto, for example, has features that look like cryovolcanoes, as does Saturn’s moon Titan and Jupiter’s moon Ganymede. These locations are extremely cold and known to contain large quantities of methane and water, so internal heating (caused by radioactive decay or tidal processes) melt the ices and force them to the surface. When they vent through the crust, gases are released and the liquids quickly freeze and sublimate.
Around these vents, cryovolcanoes will grow, and if Ceres really does have its own ice volcanoes, this will be the closest planetary body to the sun (and Earth) known to have them.
Now, in research headed by the Max Planck Institute for Solar System Research (MPS) in Göttingen, Germany, scientists using Dawn data have, for the first time, taken a stab at dating the age of the bright material in the center of Occator Crater and realized that the location has likely been the site of many cryovolcanic eruptions in the recent past.
In the center of Occator, a pit measuring around 7 miles wide can be found, likely formed during the massive impact approximately 30 million years ago. But around the edges of that pit are mountains, some 750 meters high, and in the center is a cracked dome measuring 400 meters high and nearly 2 miles wide. This bright dome is called Cerealia Facula and surrounding it appears to be material that was spewed from a cryovolcanic vent. Analysis has shown that this material contains salts that were formed in the presence of water from Ceres’ interior and then deposited onto the surface. The minerals around Cerealia Facula has been dated to only four million years, meaning that there has been cryovolcanic eruptions long after the Occator impact punctured Ceres’ crust.
“The age and appearance of the material surrounding the bright dome indicate that Cerealia Facula was formed by a recurring, eruptive process, which also hurled material into more outward regions of the central pit,” said Andreas Nathues, lead investigator of Dawn’s Framing Camera. “A single eruptive event is rather unlikely.” As noted in an MPS news release, Jupiter moons Callisto and Ganymede have similar features that are also believed to be related to cryovolcanic eruptions.
“The large impact that tore the giant Occator crater into the surface of the dwarf planet must have originally started everything and triggered the later cryovolcanic activity,” added Nathues.
Previous imagery of haze inside Occator Crater has led to the suspicion that ices remain on the surface today; the haze could be vapor from sublimating water ice exposed on the surface having been forced to the surface from Ceres’ interior. Evidence for this haze has been supported by other studies and appears to vary throughout the day as one would expect — increased sunlight would accelerate sublimation (ice turning from a solid to a vapor without passing through the liquid phase).
If volatiles are still being extruded through this vent today, this would seem to indicate that, in addition to the cryovolcanic eruptions in the last four million years, some form of activity continues to this day. Add this to the recent discovery of organic material on Ceres’ surface, this small world has become a very big asset for planetary science.
For more on Ceres’ icy eruptions, check out one of my last DNews videos:
Last week’s Juno flyby of Earth was an exciting event. NASA’s Jupiter-bound mission buzzed our planet on Wednesday (Oct. 9) only 350 miles from the surface, providing amateur astronomers with an opportunity to snapshot Juno as she flew past, stealing a little momentum from Earth and sling-shotting toward the largest planet in the Solar System. Alas, the flyby event wasn’t without incident.
The spacecraft dropped into “safe mode” shortly after its terrestrial encounter. Safe mode is a fail safe on spacecraft that protects onboard instruments from an unexpected condition. This can come in the form of a power spike or some other instrumental error. It is not known at this time what triggered this particular event, but the upshot is that Juno is back in its nominal state.
“Onboard Juno, the safe mode turned off instruments and a few non-critical spacecraft components, and pointed the spacecraft toward the Sun to ensure the solar arrays received power. The spacecraft acted as expected during the transition into and while in safe mode.”
Juno’s planned trajectory was not impacted during the flyby and it is expected to make orbital insertion around Jupiter in July 2016.
The mission was launched from Cape Canaveral, Fla., in 2011 and, through a wonderful bit of orbital mechanics, was commanded to do one 2-year orbit around the Sun. Then, last week, it ended up where it started to use our planet as a speed booster, flinging it further out into the Solar System toward Jupiter’s orbit. This acceleration “freebie” was needed as the launch vehicle, an Atlas V rocket, didn’t have the oomph to propel the spacecraft deeper into space.
Once Juno arrives at Jupiter, it will give the gas giant a thorough full-body examination, investigating what lies beneath its clouds, how it generates its powerful magnetic field and how it evolved. The repercussions of Juno’s one-year primary mission will hopefully expose not only how Jupiter is formed, but how Earth evolved into its current state.
As Juno sped past on Wednesday, I allowed myself an early celebration of some fine flying by NASA scientists with a Gin & Tonic (or a Juno & Tonic) in my special JPL-bought Juno glasses.
Good luck Juno, will look forward to seeing you at Jupiter in a little under three years time!
As NASA has been shuttered by the insane U.S. government shutdown, there’s been little in the way of news releases from NASA (site offline) or NASA’s Jet Propulsion Laboratory (site still online, but no recent updates posted). In this Mars Science Laboratory science lull, I’ve found myself obsessively trawling the mission’s raw image archive so I can get my fix of high-resolution imagery from Curiosity’s ongoing mission inside Gale Crater.
While getting lost in the Martian landscape once more, I started tinkering with Curiosity’s raw photos; zooming in, adjusting the contrast, brightness and color. One thing led to another and I found myself stitching together various photos from the rover’s Mastcam camera. Being awash with photographs with little professional insight from mission scientists (as, you know, a noisy minority at Capitol Hill has gagged them by starving the agency of funds), I started to tinker in Photoshop, blindly trying to stitch a selection of Mastcam photos together to see an updated Martian panorama once more. This is the result.
Of particular interest, I found myself staring at the precariously-shaped boulder to the far right of the panorama. I can only guess what geological processes shaped it that way — Wind action? Ancient water flow? — or whether it had simply landed that way after getting blasted from an impact crater, but I was curious as to what JPL mission scientists are making of it. Alas, we’ll have to wait a little longer for the awesome Mars science to begin flowing again.
Here’s that rock:
It felt nice to be absorbed in the Mars landscape again. The photo stitching is rough in places (by far the hardest task was getting the brightness and contrast correct in each photo) and I lack any calibration tools to ensure the color is correct or that the orientation is sound, but it satisfied my curiosity as to what Curiosity was up to on the Red Planet. It has, after all, been over a year since the historic landing of the NASA mission and the regular news updates from NASA and JPL have become something of an intellectual opiate.
Going cold turkey, apparently, makes a space blogger itchy.
It’s been a looooong time since I last updated Astroengine.com, so first off, apologies for that. But today seems as good a time as any to crank up the ‘engine’s servers as the White House has rubber-stamped a manned NASA mission to an asteroid! However, this isn’t what the President originally had in mind in 2009 when he mandated the US space agency with the task of getting astronauts to an asteroid by the mid-2020’s.
In a twist, it turns out that NASA will be basing their manned asteroid jaunt on a 2011 Keck Institute study. To cut a long story short (you can read the long story in my Discovery News article on the topic: “NASA to Hunt Down and Capture an Asteroid“), NASA will launch an unmanned spacecraft to hunt down a small space rock specimen, “lasso” it (although “bagging” it would be more accurate) and drag the wild asteroid to park it at the Earth-moon Lagrangian point, L2. Then we can treat it like a fast food store; we can fly to and from, chipping off pieces of space rock, return samples to Earth and do, well, SCIENCE!
Overall, this robotic capture/manned exoplration of an asteroid saves cash and “optimizes” the science that can be done. It also lowers the risk associated with a long-duration mission into deep space. By snaring an asteroid in its natural habitat and dragging it back to the Earth-moon system, we avoid astronauts having to spend months in deep space. The EML2 point is only days away.
But when watching the exciting NASA video after the news broke today, I kept thinking…
But that wasn’t the only thing I was thinking. I was also thinking: what’s the point? It’s flashy and patriotic, but where’s the meat?
The human component of this asteroid mission has now been demoted to second fiddle. Sure, it will utilize NASA’s brand new Orion spacecraft and be one of the first launches of the Space Launch System (SLS), but what will it achieve? Astronauts will fly beyond Moon orbit, dock with the stationary space rock and retrieve samples as they please, but why bother with astronauts at all?
It is hoped that the robotic asteroid bagging spacecraft could launch by 2017 and, assuming a few years to steer the asteroid to EML2, a human mission would almost certainly be ready by the mid-2020s. But by that time, sufficiently advanced robotics would be available for unmanned sample retrieval. Heck, as telepresence technology matures, the EML2 point will be well within the scope for a live feed — light-time between Earth and the EML2 point will only be a few seconds, perhaps a little more if communications need to be relayed around the Moon. Robotics could be controlled live by a “virtual astronaut” on Earth — we probably have this capability right now.
The most exciting thing for me is the robotic component of asteroid capture. The advances in asteroid rendezvous and trajectory modification techniques will be cool, although scaling the asteroid bagging technique up (for large asteroids that could actually cause damage should they hit Earth) would be a challenge (to put it mildly). At a push, it may even be of use to a theoretical future asteroid mining industry. The rationale is that if we can understand the composition of a small asteroid, we can hope to learn more about its larger cousins.
The human element seems to be an afterthought and purely a political objective. There will undoubtedly be advancements in life support and docking technologies, but it will only be a mild taster for the far grander (original) NASA plan to send a team of astronauts into deep space to study an asteroid far away from the Earth-Moon system. The argument will be “an asteroid is a stepping stone to Mars” — sadly, by watering down the human element in an already questionable asteroid mission, it’s hard to see the next step for a long-duration spaceflight to Mars.
From this logic, we may as well just keep sending robots. But that wasn’t the point, was it?
UPDATE 1:That whole thing I said in my Al Jazeera English op-ed about being blinkered on the organics explanation for the “big” news on Monday? Well, case in point, as tweeted by @MarsToday on Sunday night, perhaps Curiosity has discovered further evidence for perchlorates on Mars. I have no clue where this information is sourced, and I’m not going to speculate any more, but if perchlorates have been discovered in Gale Crater, it would support the findings of NASA’s 2008 Mars Phoenix lander findings of perchlorate and possible liquid water brine in the arctic regions of the Red Planet. Place your bets…
Over the last bizarre few days, a key NASA scientist (almost) spilled the beans on a “historic” discovery by the Mars Science Laboratory (MSL) rover Curiosity. Then, speculation ran wild. Had NASA’s newest Mars surface mission discovered organics? Feeling the need to stamp out the glowing embers of organic excitement ahead of the Dec. 3 AGU press conference, NASA said that there would be no big announcement on Monday. But then the agency went even further, issuing a terse statement to point out that the speculation is wrong. “At this point in the mission, the instruments on the rover have not detected any definitive evidence of Martian organics,” said NASA.
So now we’re left, understandably, wondering what lead MSL scientist John Grotzinger was referring to. I think it’s safe to assume that he wasn’t misquoted by the NPR journalist who happened to be sitting in his office when the MSL team was receiving data from the mission’s Sample Analysis at Mars (SAM) instrument. And if we take NASA’s damage-controlling statements at face value, Grotzinger was just getting excited for all the data being received from the rover — after all, the entire mission is historic.
As a science media guy with a background in science, I totally ‘get’ what the MSL team are going through. Scientists are only human and whether or not Grotzinger was getting excited for a specific “historic” find or just getting generally excited for all the “historic” data streaming from the rover, is irrelevant. Perhaps he should have been more careful as to the language he used when having an NPR reporter sitting in the same room as him, but that’s academic, I’m pretty sure that if I was leading the most awesome Mars mission in the history of Mars missions I’d be brimming over with excitement too. The scientific process is long and can often seem labored and secretive to the media and public — rumors or a few slipped words from scientists is often all that’s needed to spawn the hype. But for the scientific process to see its course, data needs to be analyzed, re-analyzed and theories need to be formulated. In an announcement as important as “organics on Mars,” the science needs to be watertight.
However, I can’t help but feel that, in NASA’s enthusiasm to “keep the lid” on speculation, that they are setting themselves up for a backlash on Monday.
If the AGU press conference is just “an update about first use of the rover’s full array of analytical instruments to investigate a drift of sandy soil,” as the NASA statement says, won’t there be any mention of organics? Will this be a similar announcement to the sampling of Mars air in the search for methane? The upshot of that Nov. 2 press conference was that the Mars air had been tested by SAM and no methane (within experimental limits) had been discovered… yet. But this was a sideline to the announcement of some incredible science as to the evolution of the Martian atmosphere.
This time, although there may not be “definitive,” absolute, watertight proof of organics, might mission scientists announce the detection of something that appears to be organics… “but more work is needed”? It’s a Catch 22: It’s not the “historic” news as the experiment is ongoing pending a rock-solid conclusion; yet it IS “historic” as the mere hint of a detection would bolster the organics experiments of the Viking landers in the 1970s and could hint at the discovery of another piece of the “Mars life puzzle.” And besides, everything Curiosity does is “historic.”
In NASA’s haste to damper speculation, have they cornered themselves into not making any big announcements on Monday? Or have they only added to the speculation, bolstering the media’s attention? Besides, I get the feeling that the media will see any announcement as a “big” announcement regardless of NASA scientists’ intent. Either way, it’s a shame that the hype may distract from the incredible science the MSL team are carrying out every single day.
Meanwhile, in deep space, a little probe launched 35 years ago is edging into the interstellar medium and NASA’s Voyager Program team are also holding an AGU press conference on Monday. Although there have been no NPR journalists getting the scoop from mission scientists, it’s worth keeping in mind that Voyager 1 really is about to make history. In October, I reported that the particle detectors aboard the aging spacecraft detected something weird in the outermost reaches of the Solar System. As Voyager 1 ventures deep into the heliosheith — the outermost component of the heliosphere (the Sun’s sphere of influence) — it detected inexplicable high-energy particles. The theory is that these particles are being accelerated by the magnetic mess that is the outermost reaches of the Solar System. But there is growing evidence in particle detections and magnetometer readings that the probe may have just left the Solar System, completely escaping the heliosphere.
A big hint is in the following graphs of data streaming from Voyager 1. The first plot shows the increase in high-energy cosmic ray particle counts. These high-energy particles typically originate from beyond the heliosphere. The bottom plot shows lower-energy particles that originate from the solar wind. Note how the lower-energy particle counts fell off a cliff this summer, and how the high-energy particles have seen a marked increase at around the same period:
So, in light of the media-centric Curiosity debate over what is “historic” and what’s not “historic” enough to be announced at conferences, I’m getting increasingly excited for what the Voyager team have got to say tomorrow. It’s inevitable that Voyager 1 will leave the Solar System, but will NASA call it at the AGU? Who knows, but that would be historic, just without the hype.
As the sols march on, NASA’s brand new nuclear-powered rover Curiosity has detected a dramatic change in its surrounding atmosphere. A once-clear vista of the distant rim of Gale Crater now looks smoggy — almost like the gray-brown-yellow stuff that hangs above Los Angeles on a hot summer’s day. So what’s causing this change in opacity?
As can be seen in the above global view of Mars, NASA’s Mars Reconnaissance Orbiter took a near-continuous observation of the planet on Nov. 18 with its Mars Color Imager. The mosaic has picked out an assortment of geographical features, but there’s one rather ominous atmospheric feature (white arrows) that grabbed the attention of Malin Space Science Systems’ Bruce Cantor.
A regional dust storm is brewing and Cantor first observed the storm on Nov. 10. He reported the detection to NASA’s Mars Exploration Rover team who manage Opportunity. Although the storm is over 800 miles from the tenacious rover, dust storms are of a concern for any solar powered surface mission, especially for a rover that has outlived its expected mission lifetime by several years. Opportunity’s solar panels are already covered in dust, so should there be an additional dip in sunlight due to a dusty atmosphere there could be an impact on its mission. Additional dust layers on the panels wouldn’t help either.
Opportunity does not have a weather station, but its cameras have detected a slight drop in atmospheric clarity. Curiosity, on the other hand, does have a weather station — called the Rover Environmental Monitoring Station (REMS) — and has been closely monitoring the atmospheric variability over the last few days, detecting a decreased air pressure and a slight rise in overnight low temperature. This is in addition to the dramatic loss in visibility. In short, it sounds like Curiosity can sense a storm in the air.
“This is now a regional dust storm. It has covered a fairly extensive region with its dust haze, and it is in a part of the planet where some regional storms in the past have grown into global dust hazes,” said Rich Zurek, chief Mars scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “For the first time since the Viking missions of the 1970s, we are studying a regional dust storm both from orbit and with a weather station on the surface.”
Now this is the cool bit. We currently have an armada of Mars orbiters, plus two generations of Mars rovers doing groundbreaking work on opposite sides of the red planet. We are in an unprecedented age of planetary exploration where a network of robots all work in concert to aid our understanding of how the planet works. In this case, local weather changes are being observed around two surface missions while corroborating data is being gathered hundreds of miles overhead.
Starting on Nov. 16, the Mars Climate Sounder instrument on the Mars Reconnaissance Orbiter detected a warming of the atmosphere at about 16 miles (25 kilometers) above the storm. Since then, the atmosphere in the region has warmed by about 45 degrees Fahrenheit (25 degrees Celsius). This is due to the dust absorbing sunlight at that height, so it indicates the dust is being lofted well above the surface and the winds are starting to create a dust haze over a broad region.
Warmer temperatures are seen not only in the dustier atmosphere in the south, but also in a hot spot near northern polar latitudes due to changes in the atmospheric circulation. Similar changes affect the pressure measured by Curiosity even though the dust haze is still far away.
We’re monitoring weather on another planet people! If that’s not mind-blowing, I don’t know what is.
Note: Apologies for the Astroengine.com hiatus, I’ve been somewhat distracted with writing duties at Discovery News and Al Jazeera English. If you’re ever wondering where I’ve disappeared to, check in on my Twitter feed, I tweet a lot!
Late on Sunday night, NASA’s Mars Science Laboratory (MSL) website had a surprise in store: Curiosity’s recently un-capped robotic arm-mounted Mars Hand Lens Imager (MAHLI) snapped some incredible photographs of the rover’s undercarriage and its calibration target. Shown above is my favorite pic, detailing dust on two of the rover’s wheels. Shown below is an image of Curiosity’s set of front Hazcams (left and right pairs).
Although the dust cap has been in place up until now, the camera was used to grab Curiosity’s first fuzzy color landscape pic and, only last night, it was used to snap a fuzzy “self portrait” of Curiosity’s “head” — but that was achieved by looking through the semi-transparent dust cap still attached to the lens. Today, the very first crystal-clear “open” MAHLI image has been acquired after mission controllers sent the command for the re-closable dust cap to swing open. The picture shows a patch of Mars dirt next to the rover measuring about 86 centimeters across. The large pebble at the bottom of the frame is about 8 cm wide.
This may be a very preliminary image, but the MSL team are already using it to do science. “Notice that the ground immediately around that pebble has less dust visible (more gravel exposed) than in other parts of the image,” says the image description on the MSL mission site. “The presence of the pebble may have affected the wind in a way that preferentially removes dust from the surface around it.”
During the Sept. 6 press conference from NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., Mars Science Laboratory (MSL) mission scientists discussed updates from Curiosity’s progress in Gale Crater. It’s hard to keep up with the incredible deluge of images and scientific data as the six-wheeled rover roves toward its first target — a geologically interesting location called “Glenelg.” Mission managers hope to use Curiosity’s drill for the first time when the rover arrives. Expect mission updates and some pretty cool photos to appear on Discovery News throughout the day.
There was one photograph, however, imaged by the rover’s Mastcam that was showcased in today’s briefing that fascinated me. Shown above, the Mars Hand Lens Imager (MAHLI) can be seen on the rover’s robotic arm (with dust cap still in place). All the instrumentation and wiring has a very cool Steampunk-esque quality to it.
When I “met” Curiosity at the JPL clean room last year, I was also fascinated by its ugly functionality. By “ugly,” I don’t mean repulsive, I actually fell in love with the robot that day. But with any space mission, function succeeds form and Curiosity is no different. Instruments jut out from a central box; cables snake over all surfaces; gold and silver components are scattered across the deck like opulent jewels; and the whole thing is supported by some seriously heavy duty wheels that wouldn’t look out of place attached to a Bentley cruising through Los Angeles.
Back then, I stared at the Mars exploration machine, whose one purpose is to do science in an alien land, and thought how alien the thing looked. But in all the ugliness of an apparently random assortment of instrumentation, Curiosity has an undeniably beautiful character. Also, it has a WALL-E-like “head” in the form of the blocky ChemCam atop its mast. And now I know what its character is after seeing this latest robotic arm photo; it’s a creation that wouldn’t look out of place in a Steampunk museum or imagined in a H. G. Wells novel. However, this isn’t sci-fi, this is real. We have a nuclear-powered rover on Mars. Sometimes it’s too hard to put such awesomeness into words.