Dawn's framing camera took these images of Ceres on April 10, 2015 which were combined into a short animation. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Brand new images taken on April 10 by NASA’s Dawn probe show the dwarf planet from high above its north pole. Photographed at a distance of just 21,000 miles (33,000 km) — less than 1/10 the Earth-moon distance — they’re our sharpest views to date. The crispness combined with the low-angled sunlight gives Ceres a stark, lunar-like appearance.
Artist’s concept of Dawn above Ceres around the time it was captured into orbit by the dwarf planet in early March. Since its arrival, the spacecraft turned around to point the blue glow of its ion engine in the opposite direction. Because it’s been facing the Sun while lowering its orbit, the new images of Ceres show it as a crescent. Credit: NASA/JPL
Images will only get better. Dawn arrived at Ceres on March 6 and immediately got to work using its ion thrusters in conjunction with the dwarf planet’s gravity to gradually lower itself into a circular orbit. Once the spacecraft settles into its first science orbit on April 23 at a distance of 8,400 miles from the surface, it will begin taking a hard look at this cratered mini-planet. A little more than two weeks later, the probe will spiral down for an even closer view on May 9.
The map is an enhanced color view that offers an expanded range of the colors visible to human eyes. Pictures were taken using blue, green and infrared filters and combined. Scientists use this technique to highlight subtle color differences across Ceres, which can provide insights into the physical properties and composition of the surface. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/ID
Dawn’s gravity spiral continues throughout the summer and fall until the probe tiptoes down to just 233 miles (375 km) altitude in late November. From there it will deploy its Gamma Ray and Neutron Detector (GRaND) to map the elements composing Ceres’ surface rocks. We’re in for a great ride!
Simulated Ceres rotation by Tom Ruen using the new color map
Meanwhile, scientists have assembled images taken by Dawn through blue, green and infrared filters to create a new color-enhanced map of the dwarf planet. The variety of landforms in conjunction with the color variations hint that Ceres was once an active body or one with the means to resurface itself from within. Mechanisms might involve internal heating and / or movement of water or ice.
Pictures from Dawn’s VIR instrument highlight two regions on Ceres containing bright spots. The top images show a region scientists labeled “1” and the bottom images show the region labeled “5,” which show the Ceres’ brightest pair of spots. Region 1 is cooler than the rest of Ceres’ surface, but region 5 appears to be located in a region that is similar in temperature to its surroundings. Credit: NASA/JPL-Caltech/UCLA/ASI/INAF
There are still no new close-ups of the pair of enigmatic white spots taunting us from inside that 57-mile-wide crater. But there is a bit of news. Dawn’s visible and infrared mapping spectrometer or VIR has already examined Ceres in visible and infrared or thermal light. Data from VIR indicate that light and darker regions on the dwarf planet have different properties.
A topographic map of Ceres with provisional names given to each quadrangle. Ceres’ craters are named for agricultural gods; other features after world agricultural festivals. Let’s hope the names are made permanent. I mean, you can’t beat Yumyum. Credit: NASA / JPL / UCLA / MPS / DLR / IDA / JohnVV / Emily Lakdawalla
The bright spots are located in a region with a temperature similar to its surroundings. However, a different bright feature appears in a region that’s cooler than the neighboring surface. Exactly what those variations are telling us will hopefully become clear once Dawn returns more detailed images:
“The bright spots continue to fascinate the science team, but we will have to wait until we get closer and are able to resolve them before we can determine their source,” said Chris Russell, principal investigator for the Dawn mission.
We’ve seen way too many science fiction episodes that show asteroid belts as dense fields of tumbling boulders. How dense is the asteroid belt, and how to spacecraft survive getting through them?
For the purposes of revenue, lazy storytelling, and whatever it is Zak Snyder tells himself to get out of bed in the morning, when it comes to asteroids, Science fiction and video games creators have done something of disservice to your perception of reality.
Take a fond trip down sci-fi memory lane, and think about the time someone, possibly you, has had to dogfight or navigate through yet another frakkin’ asteroid belt. Huge space rocks tumbling dangerously in space! Action! Adventure! Only the skilled pilot, with her trusty astromecha-doplis ship can maneuver through the dense cluster of space boulders, dodging this way and that, avoiding certain collision.
And then she shoots her pew pew laser breaking up larger asteroids up into smaller ones, possibly obliterating them entirely depending on the cg budget. Inevitably, there’s bobbing and weaving. Pursuit craft will clip their wings on asteroids, spinning off into nearby tango. Some will fly straight into a space boulder.
Finally you’ll thread the needle on a pair of asteroids and the last ship of the whatever they’re called clicky clacky mantis Zorak bug people will try and catch you, but he/it won’t be quite so lucky. Poetically getting squashed like… a… bug. Sackhoff for the win, pilot victorious.
Okay, you probably knew the laser part is totally fake. I mean, everybody knows you can’t hear sounds in space. Outside of Starbuck being awesome, is that at all realistic? And if so, how does NASA maneuver unmanned spacecraft through that boulder-strewn grand canyon death trap to reach the outer planets?
The asteroid belt is a vast region between the orbits of Mars and Jupiter. Our collection of space rocks starts around 300 million kilometers from the Sun and ends around 500 million kilometers. The first asteroid, the dwarf planet Ceres which measures 950 km across, was discovered in 1801, with a “That’s funny.”. Soon after astronomers turned up many more small objects orbiting in this region at the “Oooh neat!” stage.
Artist’s concept of Dawn in its survey orbit at dwarf planet Ceres. Credit: NASA/JPL-Caltech
They realized it was a vast belt of material orbiting the Sun, with I suspect a “We’re all gonna die.”. To date, almost half a million asteroids have been discovered, most of which are in the main belt.
As mentioned in a another video, gathering up all the material in the asteroid belt and gluing it together makes a mass around 4% of the Moon. So, in case one of your friends gets excited and suggests it was a failed planet, you can bust out that stat and publicly shame them for being so 1996, Goodwill Hunting style. You like asteroids? How about them asteroids?
There’s a few hundred larger than 100 km across, and tens of millions of rocks a hundred meters across. Any one of these could ruin a good day, or bring a bad day to a welcome firey close for either a depressed wayfaring spacecraft or a little bluegreen speck of a planet. Which sounds dangerous all the way around.
Fortunately, our asteroid belt is a vast region of space. Let’s wind up the perspective-o-meter. If you divide the total number of objects in the field by the volume of space that asteroid belt takes up, each space rock is separated by hundreds of thousands of kilometers. Think of it as gravity’s remarkably spacious zen rock garden.
Ceres compared to asteroids visited to date, including Vesta, Dawn’s mapping target in 2011. Image by NASA/ESA. Compiled by Paul Schenck.
As a result, when NASA engineers plot a spacecraft’s route through the asteroid belt, they don’t expect to make a close encounter with any asteroids – in fact, they’ll change its flight path to intercept asteroids en route. Because hey look, asteroid!
Even though Ceres was discovered in 1801, it’s never been observed up close, until now. NASA’s Dawn spacecraft already visited Asteroid Vesta, and by the time you’re watching this video, it will have captured close-up images of the surface of Ceres.
Once again, science fiction creatives sold us out to drama over hard science. If you’re passing through an asteroid belt, you won’t need to dodge and weave to avoid the space rocks. In fact, you probably wouldn’t even know you were passing through a belt at all. You’d have to go way the heck over there to even get a nearby look at one of the bloody things. So we’re safe, our speck is safe, and all the little spacecraft are safe…. for now.
Which dramatic version of “asteroids” are you most fond of? Tell us in the comments below.
The slim crescent of Ceres smiles back as the dwarf planet awaits the arrival of an emissary from Earth. This image was taken by NASA’s Dawn spacecraft on March 1, 2015, just a few days before the mission achieved orbit around the dwarf planet. Because of its angle of approach (see video above) Dawn saw Ceres from its backside, which from its perspective, was mostly in darkness. Credit: NASA/JPL
Dawn’s approach and trajectory as it begins its orbital “dance” with Ceres. As you watch, note the timeline at upper right.
Dawn made it! After a 14-month tour of the asteroid Vesta and 2 1/2 years en route to Ceres, the spacecraft felt the gentle tug of Ceres gravity and slipped into orbit around the dwarf planet at 6:39 a.m. (CST) Friday morning.
“We feel exhilarated,” said lead researcher Chris Russell at the University of California, Los Angeles, after Dawn radioed back the good news.
Not only is this humankind’s first probe to orbit a dwarf planet, Dawn is the only spacecraft to fly missions to two different planetary bodies. Dawn’s initial orbit places it 38,000 miles (61,000 km) from Ceres with a view of the opposite side of Ceres from the Sun. That’s why we’ll be seeing photos of the dwarf planet as a crescent for the time being. If you watch the video, you’ll notice that Dawn won’t see Ceres’ fully sunlit hemisphere until early-mid April.
Dawn’s spiral descent from survey orbit to the high altitude mapping orbit. The trajectory progresses from blue to red over the course of the six weeks. The red dashed segments are where the spacecraft is not thrusting with its ion propulsion system. Credit: NASA/JPL
The spacecraft will spend the next month gradually spiraling down to Ceres to reach its “survey orbit” of 2,730 miles in April. From there it will train its science camera and visible and infrared mapping spectrometer to gather pictures and data. The leisurely pace of the orbit will allow Dawn to spend more than 37 hours examining Ceres’ dayside per revolution. NASA will continue to lower the spacecraft throughout the year until it reaches its minimum altitude of 235 miles.
As Dawn maneuvers into orbit, its trajectory takes it to the opposite side of Ceres from the sun, providing these crescent views. These additional pictures were taken on March 1 at a distance of 30,000 miles (49,000 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“Since its discovery in 1801, Ceres was known as a planet, then an asteroid and later a dwarf planet,” said Marc Rayman, Dawn chief engineer and mission director at JPL. “Now, after a journey of 3.1 billion miles (4.9 billion kilometers) and 7.5 years, Dawn calls Ceres, home.”
More about Dawn’s incredible accomplishment can be found in the excellent Dawn Journal, written by Dawn chief engineer and mission director Marc Rayman.
Artist’s concept of Dawn in its survey orbit at dwarf planet Ceres. Credit: NASA/JPL-Caltech
On March 6, the Dawn spacecraft will ease into orbit around the dwarf planet Ceres. This is the visit to a dwarf planet (New Horizons will flyby Pluto later this year) and scientists are eager to see its surface in detail. But did you know that Ceres got its name from the ancient Roman goddess of agriculture and grain crops? Think about that when you enjoy your breakfast!
As we mentioned in our previous article about the intriguing white spots that Dawn has seen on Ceres as it makes its approach, Dawn will then continue to spiral its way down to an altitude of about 920 miles (1,480 kilometers), and in August 2015 will begin a two-month phase known as the high-altitude mapping orbit. Then, it will spiral down to an altitude of about 2,750 miles (4,430 kilometers), and obtain more science data in its survey science orbit. This phase will last for 22 days, and is designed to obtain a global view of Ceres with Dawn’s framing camera, and global maps with the visible and infrared mapping spectrometer (VIR).
Dawn will then continue to spiral its way down to an altitude of about 920 miles (1,480 kilometers), and in August 2015 will begin a two-month phase known as the high-altitude mapping orbit. During this phase, the spacecraft will continue to acquire near-global maps with the VIR and framing camera at higher resolution than in the survey phase. The spacecraft will also image in “stereo” to resolve the surface in 3-D.
Then, after spiraling down for two months, Dawn will begin its closest orbit around Ceres in late November, at a distance of about 233 miles (375 kilometers). The dance at low-altitude mapping orbit will be a long waltz — three months — and is specifically designed to acquire data with Dawn’s gamma ray and neutron detector (GRaND) and gravity investigation. GRaND will reveal the signatures of the elements on and near the surface. The gravity experiment will measure the tug of the dwarf planet, as monitored by changes in the high-precision radio link to NASA’s Deep Space Network on Earth.
Dawn’s nominal mission to Ceres is expected to last for 16 months.
Ceres rotates in this sped-up movie comprised of images taken by NASA's Dawn mission during its approach to the dwarf planet. The images were taken on Feb. 19, 2015, from a distance of nearly 29,000 miles (46,000 kilometers). Dawn observed Ceres for a full rotation of the dwarf planet, which lasts about nine hours. The images have a resolution of 2.5 miles (4 kilometers) per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
As the Dawn spacecraft prepares to enter orbit around Ceres on March 6, the science team provided the latest images and a mission preview during a briefing on March 2. The images released yesterday show more of those unusual bright spots and lots of craters, and feature two new global views of Ceres: one spinning globe, and a mosaic of a flat map-view of Ceres’ surface.
But the most-talked about feature is the 90-km-wide (57-mile) crater with two bright spots.
“These spots are extremely surprising and have been puzzling to the team and everyone that has seen them,” said Deputy Principal Investigator Carol Raymond. “The team is really, really excited about this feature because it is unique in the solar system.”
Raymond added that the team will be revealing the true nature of spots with the public in real time as the spacecraft gets closer and is able to make a determination.
So what is the leading theory on the bright spots?
The surface of Ceres is covered with craters of many shapes and sizes, as seen in this new mosaic of the dwarf planet comprised of images taken by NASA’s Dawn mission on Feb. 19, 2015 from a distance of nearly 29,000 miles (46,000 kilometers). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.
While cryovolcanoes have been bantered around as a possibility, during the briefing yesterday the science team downplayed that possibility, citing several pieces of evidence.
First, Raymond said the spots are consistent with highly reflective materials that may contain ice or salts. As an example of this, this morning, Cassini imaging lead Carolyn Porco tweeted an image of exposures of bright ice on Saturn’s moon Phoebe.
Raymond added that if the bright features end up to be liquid water, salt would be most likely element that would keep the water from freezing. The science team will also be looking for dust levitating from the surface, as sublimating gases could cause dust to rise.
Secondly, Raymond said if the bright spots were a cryovolcano, they would expect to see some type of surface evidence of a mound, peak or crack. “We don’t see that with the bright spots so a cryovolcano is unlikely,” she said.
NASA’s Dawn spacecraft took these images of dwarf planet Ceres from about 25,000 miles (40,000 kilometers) away on Feb. 25, 2015. Ceres appears half in shadow because of the current position of the spacecraft relative to the dwarf planet and the sun. The resolution is about 2.3 miles (3.7 kilometers) per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.
Third, — and this is also for anyone who may be thinking there is a beam or light-creating mechanism on the surface — team member Chris Russell said there is quite conclusive evidence that the spots are reflecting light, not creating light.
“We have followed the light curve into the terminator,” he said. “The spots do get darker and then go out when the terminator is reached.”
The terminator is the term for the boundary between day and night.
Lastly, even though in 2014 the Herschel spacecraft detected water vapor coming from two longitudal regions on Ceres (one of them is the region where crater with the bright spots is located), the current evidence points to the vaporization or sublimation of ice, not a spewing cryovolcano.
The Herschel team estimated that approximately 6 kg of water vapor is being produced per second, requiring only a tiny fraction of Ceres to be covered by water ice. This links nicely to the two localized surface features that the Herschel team observed and to the bright spots observed by Dawn.
Raymond said the Dawn science team should be able to verify the Herschel emissions, as they have modeled a similar emission coming from a distributed area and they are confident that observations with Dawn’s infrared spectrometer could detect such an emission, if present. “So if the activity is still ongoing, or if it is coming from a deposit left behind, we should be able to detect it,” she said.
This image was taken by NASA’s Dawn spacecraft of dwarf planet Ceres on Feb. 19 from a distance of nearly 29,000 miles (46,000 kilometers). It shows that the brightest spot on Ceres has a dimmer companion, which apparently lies in the same basin. Image Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
After Dawn enters orbit, it will make its first full characterization of Ceres later in April, at an altitude of about 8,400 miles (13,500 kilometers), and it will then spiral down to an altitude of about 2,750 miles (4,430 kilometers), and obtain more science data in its survey science orbit. This phase will last for 22 days, and is designed to obtain a global view of Ceres with Dawn’s framing camera, and global maps with the visible and infrared mapping spectrometer (VIR).
Dawn will then continue to spiral its way down to an altitude of about 920 miles (1,480 kilometers), and in August 2015 will begin a two-month phase known as the high-altitude mapping orbit. During this phase, the spacecraft will continue to acquire near-global maps with the VIR and framing camera at higher resolution than in the survey phase. The spacecraft will also image in “stereo” to resolve the surface in 3-D.
Then, after spiraling down for two months, Dawn will begin its closest orbit around Ceres in late November, at a distance of about 233 miles (375 kilometers), allowing Dawn’s gamma ray and neutron detector (GRaND) and gravity investigation to make their observations.
Dawn’s nominal mission to Ceres is expected to last for 16 months, until near the end of 2016. There is a possibility of an extended mission, but that will depend on the amount of fuel left in the Dawn’s tank. While Dawn’s ion engine is nearly limitless in its power, hydrazine is used for attitude control or pointing the spacecraft – pointing it to Ceres to take images and pointing it back to Earth to send data. Robert Mase, Dawn project manager said the hydrazine the most scarce resource in terms of an extended mission.
“There’s not a likely prospect of years and years ahead of us,” he said.
Jim Green, director of NASA’s Planetary Science Division said while Dawn has plenty of fuel for its nominal mission, it likely won’t last more than a few months in an extended mission.
“We will take stock of how much hydrazine is left and then go through a process of evaluation if we can give the go ahead for an extended mission,” he said. “I’m sure it will observe some really exciting things, but we have to see what the fuel reserves are before we make that decision.”
Still, Dawn will remain in a stable orbit around Ceres for hundreds of years.
